the erbb3 antibodies disclosed herein are based on the antigen binding sites of certain monoclonal antibodies selected for their ability to neutralize the biological activity of human erbb3 polypeptides . the antibodies contain immunoglobulin variable region cdr sequences that define a binding site for erbb3 . in some embodiments , the antibodies prevent erbb3 from binding to a ligand , e . g ., nrg / hrg , thereby neutralizing the biological activity of erbb3 . in other embodiments , the anti - erbb3 antibodies inhibit erbb3 dimerization , thereby neutralizing the biological activity of erbb3 . in still other embodiments , the anti - erbb3 antibodies inhibit phosphorylation of erbb3 and downstream signaling . because of the neutralizing activity of these antibodies , they are useful for inhibiting the growth and / or proliferation of certain cancer cells and tumors . the antibodies can be engineered to minimize or eliminate an immune response when administered to a human patient . in some embodiments , the antibodies are fused or conjugated to other moieties , such as detectable labels or effector molecules such as small molecule toxins . in some embodiments , the antibody comprises : ( a ) an immunoglobulin heavy chain variable region comprising the structure cdr h1 - cdr h2 - cdr h3 and ( b ) immunoglobulin light chain variable region , wherein the heavy chain variable region and the light chain variable region together define a single binding site for binding human erbb3 . a cdr h1 comprises an amino acid sequence selected from the group consisting of seq id no : 5 ( 04d01 ), seq id no : 15 ( 09d03 ), seq id no : 25 ( 11g01 ), seq id no : 34 ( 12a07 ), seq id no : 41 ( 18h02 ), seq id no : 51 ( 22a02 ), seq id no : 57 ( 24c05 ), and seq id no : 75 ( 24c05 ); a cdr h2 comprises an amino acid sequence selected from the group consisting of seq id no : 6 ( 04d01 ), seq id no : 16 ( 09d03 ), seq id no : 26 ( 11g01 ), seq id no : 35 ( 12a07 ), seq id no : 42 ( 18h02 ), seq id no : 52 ( 22a02 ), seq id no : 58 ( 24c05 ), and seq id no : 148 ( sh24c05 hv3 - 11 n62s ); and a cdr h3 comprises an amino acid sequence selected from the group consisting of seq id no : 7 ( 04d01 ), seq id no : 17 ( 09d03 ), seq id no : 27 ( 11g01 ), seq id no : 36 ( 12a07 , 22a02 ), seq id no : 43 ( 18h02 ), and seq id no : 59 ( 24c05 ). throughout the specification a particular seq id no . is followed in parentheses by the antibody that was the origin of that sequence . for example , “ seq id no : 5 ( 04d01 )” means that seq id no : 5 comes from antibody 04d01 . in some embodiments , the antibody comprises an immunoglobulin heavy chain variable region comprising a cdr h1 comprising the amino acid sequence of seq id no : 5 ( 04d01 ), a cdr h2 comprising the amino acid sequence of seq id no : 6 ( 04d01 ), and a cdr h3 comprising the amino acid sequence of seq id no : 7 ( 04d01 ). in some embodiments , the antibody comprises an immunoglobulin heavy chain variable region comprising a cdr h1 comprising the amino acid sequence of seq id no : 15 ( 09d03 ), a cdr h2 comprising the amino acid sequence of seq id no : 16 ( 09d03 ), and a cdr h3 comprising the amino acid sequence of seq id no : 17 ( 09d03 ). in some embodiments , the antibody comprises an immunoglobulin heavy chain variable region comprising a cdr h1 comprising the amino acid sequence of seq id no : 25 ( 11g01 ), a cdr h2 comprising the amino acid sequence of seq id no : 26 ( 11g01 ), and a cdr h3 comprising the amino acid sequence of seq id no : 27 ( 11g01 ). in some embodiments , the antibody comprises an immunoglobulin heavy chain variable region comprising a cdr h1 comprising the amino acid sequence of seq id no : 34 ( 12a07 ), a cdr h2 comprising the amino acid sequence of seq id no : 35 ( 12a07 ), and a cdr h3 comprising the amino acid sequence of seq id no : 36 ( 12a07 , 22a02 ). in some embodiments , the antibody comprises an immunoglobulin heavy chain variable region comprising a cdr h1 comprising the amino acid sequence of seq id no : 41 ( 18h02 ), a cdr h2 comprising the amino acid sequence of seq id no : 42 ( 18h02 ), and a cdr h3 comprising the amino acid sequence of seq id no : 43 ( 18h02 ). in some embodiments , the antibody comprises an immunoglobulin heavy chain variable region comprising a cdr h1 comprising the amino acid sequence of seq id no : 51 ( 22a02 ), a cdr h2 comprising the amino acid sequence of seq id no : 52 ( 22a02 ), and a cdr h3 comprising the amino acid sequence of seq id no : 36 ( 12a07 , 22a02 ). in some embodiments , the antibody comprises an immunoglobulin heavy chain variable region comprising a cdr h1 comprising the amino acid sequence of seq id no : 57 ( 24c05 ) or seq id no : 75 ( 24c05 ), a cdr h2 comprising the amino acid sequence of seq id no : 58 ( 24c05 ), and a cdr h3 comprising the amino acid sequence of seq id no : 59 ( 24c05 ). in certain embodiments , the antibody comprises an immunoglobulin heavy chain variable region comprising a cdr h1 comprising the amino acid sequence of seq id no : 57 ( 24c05 ), a cdr h2 comprising the amino acid sequence of seq id no : 58 ( 24c05 ), and a cdr h3 comprising the amino acid sequence of seq id no : 59 ( 24c05 ). in other embodiments , the antibody comprises an immunoglobulin heavy chain variable region comprising a cdr h1 comprising the amino acid sequence of seq id no : 75 ( 24c05 ), a cdr h2 comprising the amino acid sequence of seq id no : 58 ( 24c05 ), and a cdr h3 comprising the amino acid sequence of seq id no : 59 ( 24c05 ). in certain embodiments , the antibody comprises an immunoglobulin heavy chain variable region a cdr h1 comprising the amino acid sequence of seq id no : 57 ( 24c05 ) or seq id no : 75 ( 24c05 ), a cdr h2 comprising the amino acid sequence of seq id no : 148 ( sh24c05 hv3 - 11 n62s ), and a cdr h3 comprising the amino acid sequence of seq id no : 59 ( 24c05 ). preferably , the cdr h1 , cdr h2 , and cdr h3 sequences are interposed between human or humanized immunoglobulin frs . the antibody can be an intact antibody or an antigen - binding antibody fragment . in some embodiments , the antibody comprises ( a ) an immunoglobulin light chain variable region comprising the structure cdr l1 - cdr l2 - cdr l3 , and ( b ) an immunoglobulin heavy chain variable region , wherein the igg light chain variable region and the igg heavy chain variable region together define a single binding site for binding human erbb3 . a cdr l1 comprises an amino acid sequence selected from the group consisting of seq id no : 8 ( 04d01 , 12a07 , 22a02 ), seq id no : 18 ( 09d03 ), seq id no : 28 ( 11g01 ), seq id no : 44 ( 18h02 ), and seq id no : 60 ( 24c05 ); a cdr l2 comprises an amino acid sequence selected from the group consisting of seq id no : 9 ( 04d01 , 11g01 , 12a07 , 22a02 ), seq id no : 19 ( 09d03 ), seq id no : 45 ( 18h02 ), and seq id no : 61 ( 24c05 ); and a cdr l3 comprises an amino acid sequence selected from the group consisting of seq id no : 10 ( 04d01 , 12a07 , 22a02 ), seq id no : 20 ( 09d03 ), seq id no : 29 ( 11g01 ), seq id no : 46 ( 18h02 ), and seq id no : 62 ( 24c05 ). in some embodiments , the antibody comprises an immunoglobulin light chain variable region comprising : a cdr l1 comprising the amino acid sequence of seq id no : 8 ( 04d01 , 12a07 , 22a02 ); a cdr l2 comprising the amino acid sequence of seq id no : 9 ( 04d01 , 11g01 , 12a07 , 22a02 ); and a cdr l3 comprising the amino acid sequence of seq id no : 10 ( 04d01 , 12a07 , 22a02 ). in some embodiments , the antibody comprises an immunoglobulin light chain variable region comprising : a cdr l1 comprising the amino acid sequence of seq id no : 18 ( 09d03 ); a cdr l2 comprising the amino acid sequence of seq id no : 19 ( 09d03 ); and a cdr l3 comprising the amino acid sequence of seq id no : 20 ( 09d03 ). in some embodiments , the antibody comprises an immunoglobulin light chain variable region comprising : a cdr l1 comprising the amino acid sequence of seq id no : 28 ( 11g01 ); a cdr l2 comprising the amino acid sequence of seq id no : 9 ( 04d01 , 11g01 , 12a07 , 22a02 ); and a cdr l3 comprising the amino acid sequence of seq id no : 29 ( 11g01 ). in some embodiments , the antibody comprises an immunoglobulin light chain variable region comprising : a cdr l1 comprising the amino acid sequence of seq id no : 44 ( 18h02 ); a cdr l2 comprising the amino acid sequence of seq id no : 45 ( 18h02 ); and a cdr l3 comprising the amino acid sequence of seq id no : 46 ( 18h02 ). in one embodiment , the antibody comprises an immunoglobulin light chain variable region comprising : a cdr l1 comprising the amino acid sequence of seq id no : 60 ( 24c05 ); a cdr l2 comprising the amino acid sequence of seq id no : 61 ( 24c05 ); and a cdr l3 comprising the amino acid sequence of seq id no : 62 ( 24c05 ). preferably , the cdr l1 , cdr l2 , and cdr l3 sequences are interposed between human or humanized immunoglobulin frs . the antibody can be an intact antibody or an antigen - binding antibody fragment . in some embodiments , the antibody comprises : ( a ) an igg heavy chain variable region comprising the structure cdr h1 - cdr h2 - cdr h3 and ( b ) an igg light chain variable region comprising the structure cdr l1 - cdr l2 - cdr l3 , wherein the heavy chain variable region and the light chain variable region together define a single binding site for binding human erbb3 . the cdr h1 is an amino acid sequence selected from the group consisting of seq id no : 5 ( 04d01 ), seq id no : 15 ( 09d03 ), seq id no : 25 ( 11g01 ), seq id no : 34 ( 12a07 ), seq id no : 41 ( 18h02 ), seq id no : 51 ( 22a02 ), seq id no : 57 ( 24c05 ), and seq id no : 75 ( 24c05 ); the cdr h2 is an amino acid sequence selected from the group consisting of seq id no : 6 ( 04d01 ), seq id no : 16 ( 09d03 ), seq id no : 26 ( 11g01 ), seq id no : 35 ( 12a07 ), seq id no : 42 ( 18h02 ), seq id no : 52 ( 22a02 ), seq id no : 58 ( 24c05 ), and seq id no : 148 ( sh24c05 hv3 - 11 n62s ); and the cdr h3 is an amino acid sequence selected from the group consisting of seq id no : 7 ( 04d01 ), seq id no : 17 ( 09d03 ), seq id no : 27 ( 11g01 ), seq id no : 36 ( 12a07 , 22a02 ), seq id no : 43 ( 18h02 ), and seq id no : 59 ( 24c05 ). the cdr l1 is an amino acid sequence selected from the group consisting of seq id no : 8 ( 04d01 , 12a07 , 22a02 ), seq id no : 18 ( 09d03 ), seq id no : 28 ( 11g01 ), seq id no : 44 ( 18h02 ), and seq id no : 60 ( 24c05 ); the cdr l2 is an amino acid sequence selected from the group consisting of seq id no : 9 ( 04d01 , 11g01 , 12a07 , 22a02 ), seq id no : 19 ( 09d03 ), seq id no : 45 ( 18h02 ), and seq id no : 61 ( 24c05 ); and the cdr l3 is an amino acid sequence selected from the group consisting of seq id no : 10 ( 04d01 , 12a07 , 22a02 ), seq id no : 20 ( 09d03 ), seq id no : 29 ( 11g01 ), seq id no : 46 ( 18h02 ), and seq id no : 62 ( 24c05 ). in another embodiment , the antibody comprises an immunoglobulin heavy chain variable region selected from the group consisting of seq id no : 2 ( 04d01 ), seq id no : 12 ( 09d03 ), seq id no : 22 ( 11g01 ), seq id no : 31 ( 12a07 ), seq id no : 38 ( 18h02 ), seq id no : 48 ( 22a02 ), seq id no : 54 ( 24c05 ), and seq id no : 154 ( sh24c05 hv3 - 11 n62s ), and an immunoglobulin light chain variable region selected from the group consisting of seq id no : 4 ( 04d01 ), seq id no : 14 ( 09d03 ), seq id no : 24 ( 11g01 ), seq id no : 33 ( 12a07 ), seq id no : 40 ( 18h02 ), seq id no : 50 ( 22a02 ), seq id no : 56 ( 24c05 ), seq id no : 166 ( sh24c05 kv1 - 16 ), and seq id no : 168 ( sh24c05 kv1 - 17 ). in another embodiment , the antibody comprises an immunoglobulin heavy chain variable region comprising the amino acid sequence of seq id no : 2 ( 04d01 ), and an immunoglobulin light chain variable region comprising the amino acid sequence of seq id no : 4 ( 04d01 ). in another embodiment , the antibody comprises an immunoglobulin heavy chain variable region comprising the amino acid sequence of seq id no : 12 ( 09d03 ), and an immunoglobulin light chain variable region comprising the amino acid sequence of seq id no : 14 ( 09d03 ). in another embodiment , the antibody comprises an immunoglobulin heavy chain variable region comprising the amino acid sequence of seq id no : 22 ( 11g01 ), and an immunoglobulin light chain variable region comprising the amino acid sequence of seq id no : 24 ( 11g01 ). in another embodiment , the antibody comprises an immunoglobulin heavy chain variable region comprising the amino acid sequence of seq id no : 31 ( 12a07 ), and an immunoglobulin light chain variable region comprising the amino acid sequence of seq id no : 33 ( 12a07 ). in another embodiment , the antibody comprises an immunoglobulin heavy chain variable region comprising the amino acid sequence of seq id no : 38 ( 18h02 ), and an immunoglobulin light chain variable region comprising the amino acid sequence of seq id no : 40 ( 18h02 ). in another embodiment , the antibody comprises an immunoglobulin heavy chain variable region comprising the amino acid sequence of seq id no : 48 ( 22a02 ), and an immunoglobulin light chain variable region comprising the amino acid sequence of seq id no : 50 ( 22a02 ). in another embodiment , the antibody comprises an immunoglobulin heavy chain variable region comprising the amino acid sequence of seq id no : 54 ( 24c05 ), and an immunoglobulin light chain variable region comprising the amino acid sequence of seq id no : 56 ( 24c05 ). in another embodiment , the antibody comprises an immunoglobulin heavy chain variable region comprising the amino acid sequence of seq id no : 154 ( sh24c05 hv3 - 11 n62s ), and an immunoglobulin light chain variable region comprising the amino acid sequence of seq id no : 166 ( sh24c05 kv1 - 16 ). in another embodiment , the antibody comprises an immunoglobulin heavy chain variable region comprising the amino acid sequence of seq id no : 154 ( sh24c05 hv3 - 11 n62s ), and an immunoglobulin light chain variable region comprising the amino acid sequence of seq id no : 168 ( sh24c05 kv1 - 17 ). in other embodiments , the antibody comprises ( i ) an immunoglobulin heavy chain selected from the group consisting of seq id no : 109 ( 04d01 ), seq id no : 113 ( 09d03 ), seq id no : 117 ( 11g01 ), seq id no : 121 ( 12a07 ), seq id no : 125 ( 18h02 ), seq id no : 129 ( 22a07 ), seq id no : 133 ( 24c05 ), seq id no : 190 ( sh24c05 hv3 - 11 n62s igg1 ), and seq id no : 192 ( sh24c05 hv3 - 11 n62s igg2 ), and ( ii ) an immunoglobulin light chain selected from the group consisting of seq id no : 111 ( 04d01 ), seq id no : 115 ( 09d03 ), seq id no : 119 ( 11g01 ), seq id no : 123 ( 12a07 ), seq id no : 127 ( 18h02 ), seq id no : 131 ( 22a07 ), seq id no : 135 ( 24c05 ), seq id no : 204 ( sh24c05 kv1 - 16 kappa ), and seq id no : 206 ( sh24c05 kv1 - 17 kappa ). in another embodiment , the antibody comprises an immunoglobulin heavy chain comprising the amino acid sequence of seq id no : 109 ( 04d01 ), and an immunoglobulin light chain comprising the amino acid sequence of seq id no : 111 ( 04d01 ). in another embodiment , the antibody comprises an immunoglobulin heavy chain comprising the amino acid sequence of seq id no : 113 ( 09d03 ), and an immunoglobulin light chain comprising the amino acid sequence of seq id no : 115 ( 09d03 ). in another embodiment , the antibody comprises an immunoglobulin heavy chain comprising the amino acid sequence of seq id no : 117 ( 11g01 ), and an immunoglobulin light chain comprising the amino acid sequence of seq id no : 119 ( 11g01 ). in another embodiment , the antibody comprises an immunoglobulin heavy chain comprising the amino acid sequence of seq id no : 121 ( 12a07 ), and an immunoglobulin light chain comprising the amino acid sequence of seq id no : 123 ( 12a07 ). in another embodiment , the antibody comprises an immunoglobulin heavy chain comprising the amino acid sequence of seq id no : 125 ( 18h02 ), and an immunoglobulin light chain comprising the amino acid sequence of seq id no : 127 ( 18h02 ). in another embodiment , the antibody comprises an immunoglobulin heavy chain comprising the amino acid sequence of seq id no : 129 ( 22a02 ), and an immunoglobulin light chain comprising the amino acid sequence of seq id no : 131 ( 22a02 ). in another embodiment , the antibody comprises an immunoglobulin heavy chain comprising the amino acid sequence of seq id no : 133 ( 24c05 ), and an immunoglobulin light chain comprising the amino acid sequence of seq id no : 135 ( 24c05 ). in another embodiment , the antibody comprises an immunoglobulin heavy chain comprising the amino acid sequence of seq id no : 190 ( sh24c05 hv3 - 11 n62s igg1 ), and an immunoglobulin light chain comprising the amino acid sequence of seq id no : 204 ( sh24c05 kv1 - 16 kappa ). in another embodiment , the antibody comprises an immunoglobulin heavy chain comprising the amino acid sequence of seq id no : 192 ( sh24c05 hv3 - 11 n62s igg2 ), and an immunoglobulin light chain comprising the amino acid sequence of seq id no : 204 ( sh24c05 kv1 - 16 kappa ). in another embodiment , the antibody comprises an immunoglobulin heavy chain comprising the amino acid sequence of seq id no : 190 ( sh24c05 hv3 - 11 n62s igg1 ), and an immunoglobulin light chain comprising the amino acid sequence of seq id no : 206 ( sh24c05 kv1 - 17 kappa ). in another embodiment , the antibody comprises an immunoglobulin heavy chain comprising the amino acid sequence of seq id no : 192 ( sh24c05 hv3 - 11 n62s igg2 ), and an immunoglobulin light chain comprising the amino acid sequence of seq id no : 206 ( sh24c05 kv1 - 17 kappa ). as used herein , unless otherwise indicated , the term “ antibody ” means an intact antibody ( e . g ., an intact monoclonal antibody ) or antigen - binding fragment of a antibody ( e . g ., an antigen - binding fragment of a monoclonal antibody ), including an intact antibody or antigen - binding fragment that has been modified , engineered , or chemically conjugated . examples of antibodies that have been modified or engineered include chimeric antibodies , humanized antibodies , and multispecific antibodies ( e . g ., bispecific antibodies ). examples of antigen - binding fragments include fab , fab ′, ( fab ′) 2 , fv , single chain antibodies ( e . g ., scfv ), minibodies , and diabodies . an example of a chemically conjugated antibody is an antibody conjugated to a toxin moiety . fig1 shows a schematic representation of an intact monoclonal antibody that contains four polypeptide chains . two of the polypeptide chains are called immunoglobulin heavy chains ( h chains ), and two of the polypeptide chains are called immunoglobulin light chains ( l chains ). the immunoglobulin heavy and light chains are connected by an interchain disulfide bond . the immunoglobulin heavy chains are connected by interchain disulfide bonds . a light chain consists of one variable region ( v l in fig1 ) and one constant region ( c l in fig1 ). the heavy chain consists of one variable region ( v h in fig1 ) and at least three constant regions ( ch 1 , ch 2 and ch 3 in fig1 ). the variable regions determine the specificity of the antibody . each variable region contains three hypervariable regions known as complementarity determining regions ( cdrs ) flanked by four relatively conserved regions known as framework regions ( frs ). the three cdrs , referred to as cdr 1 , cdr 2 , and cdr 3 , contribute to the antibody binding specificity . in certain embodiments , an isolated antibody that binds human erbb3 comprises an immunoglobulin heavy chain variable region comprising an amino acid sequence that is at least 70 %, 75 %, 80 %, 85 %, 90 %, 95 %, 98 %, or 99 % identical to the entire variable region or the framework region sequence of seq id no : 2 ( 04d01 ), seq id no : 12 ( 09d03 ), seq id no : 22 ( 11g01 ), seq id no : 31 ( 12a07 ), seq id no : 38 ( 18h02 ), seq id no : 48 ( 22a02 ), seq id no : 54 ( 24c05 ), and seq id no : 154 ( sh24c05 hv3 - 11 n62s ). in certain embodiments , an isolated antibody that binds human erbb3 comprises an immunoglobulin light chain variable region comprising an amino acid sequence that is at least 70 %, 75 %, 80 %, 85 %, 90 %, 95 %, 98 %, or 99 % identical to the entire variable region or the framework region sequence of seq id no : 4 ( 04d01 ), seq id no : 14 ( 09d03 ), seq id no : 24 ( 11g01 ), seq id no : 33 ( 12a07 ), seq id no : 40 ( 18h02 ), seq id no : 50 ( 22a02 ), seq id no : 56 ( 24c05 ), seq id no : 166 ( sh24c05 kv1 - 16 ), and seq id no : 168 ( sh24c05 kv1 - 17 ). in each of the foregoing embodiments , it is contemplated herein that immunoglobulin heavy chain variable region sequences and / or light chain variable region sequences that together bind human erbb3 may contain amino acid alterations ( e . g ., at least 1 , 2 , 3 , 4 , 5 , or 10 amino acid substitutions , deletions , or additions ) in the framework regions of the heavy and / or light chain variable regions . in some embodiments , an isolated antibody binds herbb3 with a k d of 350 pm , 300 pm , 250 pm , 200 pm , 150 pm , 100 pm , 75 pm , 50 pm , 20 pm , 10 pm or lower . unless otherwise specified , k d values are determined by surface plasmon resonance methods . the surface plasmon resonance methods can be performed using the conditions described , for example , in examples 3 and 12 , where the measurements were performed at 25 ° c . and 37 ° c ., respectively . in some embodiments , the antibodies inhibit herbb3 binding to nrg1 - β1 . for example , the antibodies can have an ic 50 ( concentration at 50 % of maximum inhibition ) of about 5 nm , 2 nm or lower , when assayed using the protocols described in examples 4 and 13 . methods for producing antibodies disclosed herein are known in the art . for example , dna molecules encoding light chain variable regions and heavy chain variable regions can be chemically synthesized using the sequence information provided herein . synthetic dna molecules can be ligated to other appropriate nucleotide sequences , including , e . g ., constant region coding sequences , and expression control sequences , to produce conventional gene expression constructs encoding the desired antibodies . production of defined gene constructs is within routine skill in the art . alternatively , the sequences provided herein can be cloned out of hybridomas by conventional hybridization techniques or polymerase chain reaction ( pcr ) techniques , using synthetic nucleic acid probes whose sequences are based on sequence information provided herein , or prior art sequence information regarding genes encoding the heavy and light chains of murine antibodies in hybridoma cells . nucleic acids encoding the antibodies disclosed herein can be incorporated ( ligated ) into expression vectors , which can be introduced into host cells through conventional transfection or transformation techniques . exemplary host cells are e . coli cells , chinese hamster ovary ( cho ) cells , hela cells , baby hamster kidney ( bhk ) cells , monkey kidney cells ( cos ), human hepatocellular carcinoma cells ( e . g ., hep g2 ), and myeloma cells that do not otherwise produce igg protein . transformed host cells can be grown under conditions that permit the host cells to express the genes that encode the immunoglobulin light and / or heavy chain variable regions . specific expression and purification conditions will vary depending upon the expression system employed . for example , if a gene is to be expressed in e . coli , it is first cloned into an expression vector by positioning the engineered gene downstream from a suitable bacterial promoter , e . g ., tip or tac , and a prokaryotic signal sequence . the expressed secreted protein accumulates in refractile or inclusion bodies , and can be harvested after disruption of the cells by french press or sonication . the refractile bodies then are solubilized , and the proteins refolded and cleaved by methods known in the art . if a dna construct encoding an antibody disclosed herein is to be expressed in eukayotic host cells , e . g ., cho cells , it is first inserted into an expression vector containing a suitable eukaryotic promoter , a secretion signal , igg enhancers , and various introns . this expression vector optionally contains sequences encoding all or part of a constant region , enabling an entire , or a part of , a heavy and / or light chain to be expressed . in some embodiments , a single expression vector contains both heavy and light chain variable regions to be expressed . the gene construct can be introduced into eukaryotic host cells using conventional techniques . the host cells express v l or v h fragments , v l - v h heterodimers , v h - v l or v l - v h single chain polypeptides , complete heavy or light immunoglobulin chains , or portions thereof , each of which may be attached to a moiety having another function ( e . g ., cytotoxicity ). in some embodiments , a host cell is transfected with a single vector expressing a polypeptide expressing an entire , or part of , a heavy chain ( e . g ., a heavy chain variable region ) or a light chain ( e . g ., a light chain variable region ). in other embodiments , a host cell is transfected with a single vector encoding ( a ) a polypeptide comprising a heavy chain variable region and a polypeptide comprising a light chain variable region , or ( b ) an entire immunoglobulin heavy chain and an entire immunoglobulin light chain . in still other embodiments , a host cell is co - transfected with more than one expression vector ( e . g ., one expression vector expressing a polypeptide comprising an entire , or part of , a heavy chain or heavy chain variable region , and another expression vector expressing a polypeptide comprising an entire , or part of , a light chain or light chain variable region ). a method of producing a polypeptide comprising an immunoglobulin heavy chain variable region or a polypeptide comprising an immunoglobulin light chain variable region may comprise growing a host cell transfected with an expression vector under conditions that permits expression of the polypeptide comprising the immunoglobulin heavy chain variable region or the polypeptide comprising the immunoglobulin light chain variable region . the polypeptide comprising a heavy chain variable region or the polypeptide comprising the light chain variable region then may be purified using techniques well known in the art , e . g ., affinity tags such as glutathione - s - transferase ( gst ) and histidine tags . a method of producing a monoclonal antibody that binds human erbb3 , or an antigen - binding fragment of the antibody , may comprise growing a host cell transfected with : ( a ) an expression vector that encodes a complete or partial immunoglobulin heavy chain , and a separate expression vector that encodes a complete or partial immunoglobulin light chain ; or ( b ) a single expression vector that encodes both chains ( e . g ., complete or partial chains ), under conditions that permit expression of both chains . the intact antibody ( or antigen - binding fragment ) can be harvested and purified using techniques well known in the art , e . g ., protein a , protein g , affinity tags such as glutathione - s - transferase ( gst ) and histidine tags . it is within ordinary skill in the art to express the heavy chain and the light chain from a single expression vector or from two separate expression vectors . methods for reducing or eliminating the antigenicity of antibodies and antibody fragments are known in the art . when the antibodies are to be administered to a human , the antibodies preferably are “ humanized ” to reduce or eliminate antigenicity in humans . preferably , a humanized antibody has the same or substantially the same affinity for the antigen as the non - humanized mouse antibody from which it was derived . in one humanization approach , chimeric proteins are created in which mouse immunoglobulin constant regions are replaced with human immunoglobulin constant regions . see , e . g ., morrison et al ., 1984 , p roc . n at . a cad . s ci . 81 : 6851 - 6855 , neuberger et al ., 1984 , n ature 312 : 604 - 608 ; u . s . pat . nos . 6 , 893 , 625 ( robinson ); 5 , 500 , 362 ( robinson ); and 4 , 816 , 567 ( cabilly ). in an approach known as cdr grafting , the cdrs of the light and heavy chain variable regions are grafted into frameworks from another species . for example , murine cdrs can be grafted into human frs . in some embodiments , the cdrs of the light and heavy chain variable regions of an anti - erbb3 antibody are grafted onto human frs or consensus human frs . to create consensus human frs , frs from several human heavy chain or light chain amino acid sequences are aligned to identify a consensus amino acid sequence . cdr grafting is described in u . s . pat . nos . 7 , 022 , 500 ( queen ); 6 , 982 , 321 ( winter ); 6 , 180 , 370 ( queen ); 6 , 054 , 297 ( carter ); 5 , 693 , 762 ( queen ); 5 , 859 , 205 ( adair ); 5 , 693 , 761 ( queen ); 5 , 565 , 332 ( hoogenboom ); 5 , 585 , 089 ( queen ); 5 , 530 , 101 ( queen ); jones et al . ( 1986 ) n ature 321 : 522 - 525 ; riechmann et al . ( 1988 ) n ature 332 : 323 - 327 ; verhoeyen et al . ( 1988 ) s cience 239 : 1534 - 1536 ; and winter ( 1998 ) febs l ett 430 : 92 - 94 . in an approach called “ superhumanization ™,” human cdr sequences are chosen from human germline genes , based on the structural similarity of the human cdrs to those of the mouse antibody to be humanized . see , e . g ., u . s . pat . no . 6 , 881 , 557 ( foote ); and tan et al ., 2002 , j . i mmunol 169 : 1119 - 1125 . other methods to reduce immunogenicity include “ reshaping ,” “ hyperchimerization ,” and “ veneering / resurfacing .” see , e . g ., vaswami et al ., 1998 , a nnals of a llergy , a sthma , & amp ; i mmunol . 81 : 105 ; roguska et al ., 1996 , p rot . e ngineer 9 : 895 - 904 ; and u . s . pat . no . 6 , 072 , 035 ( hardman ). in the veneering / resurfacing approach , the surface accessible amino acid residues in the murine antibody are replaced by amino acid residues more frequently found at the same positions in a human antibody . this type of antibody resurfacing is described , e . g ., in u . s . pat . no . 5 , 639 , 641 ( pedersen ). another approach for converting a mouse antibody into a form suitable for medical use in humans is known as activmab ™ technology ( vaccinex , inc ., rochester , n . y . ), which involves a vaccinia virus - based vector to express antibodies in mammalian cells . high levels of combinatorial diversity of igg heavy and light chains are said to be produced . see , e . g ., u . s . pat . nos . 6 , 706 , 477 ( zauderer ); 6 , 800 , 442 ( zauderer ); and 6 , 872 , 518 ( zauderer ). another approach for converting a mouse antibody into a form suitable for use in humans is technology practiced commercially by kalobios pharmaceuticals , inc . ( palo alto , calif .). this technology involves the use of a proprietary human “ acceptor ” library to produce an “ epitope focused ” library for antibody selection . another approach for modifying a mouse antibody into a form suitable for medical use in humans is human engineering ™ technology , which is practiced commercially by xoma ( us ) llc . see , e . g ., pct publication no . wo 93 / 11794 and u . s . pat . nos . 5 , 766 , 886 ; 5 , 770 , 196 ; 5 , 821 , 123 ; and 5 , 869 , 619 . any suitable approach , including any of the above approaches , can be used to reduce or eliminate human immunogenicity of an antibody disclosed herein . methods of making multispecific antibodies are known in the art . multi - specific antibodies include bispecific antibodies . bispecific antibodies are antibodies that have binding specificities for at least two different epitopes . exemplary bispecific antibodies bind to two different epitopes of the antigen of interest . bispecific antibodies can be prepared as full length antibodies or antibody fragments ( e . g ., f ( ab ′) 2 bispecific antibodies and diabodies ) as described , for example , in milstein et al ., n ature 305 : 537 - 539 ( 1983 ), wo 93 / 08829 , traunecker et al ., embo j ., 10 : 3655 - 3659 ( 1991 ), wo 94 / 04690 , suresh et al ., m ethods in e nzymology , 121 : 210 ( 1986 ), wo96 / 27011 , brennan et al ., s cience , 229 : 81 ( 1985 ), shalaby et al ., j . e xp . m ed ., 175 : 217 - 225 ( 1992 ), kostelny et al ., j . i mmunol ., 148 ( 5 ): 1547 - 1553 ( 1992 ), hollinger et al ., pnas , 90 : 6444 - 6448 , gruber et al ., j . i mmunol ., 152 : 5368 ( 1994 ), wu et al ., n at . b iotechnol ., 25 ( 11 ): 1290 - 1297 , u . s . patent publication no . 2007 / 0071675 , and bostrom et al ., s cience 323 : 1640 - 1644 ( 2009 ). in some embodiments , the antibody is conjugated to an effector agent such as a small molecule toxin or a radionuclide using standard in vitro conjugation chemistries . if the effector agent is a polypeptide , the antibody can be chemically conjugated to the effector or joined to the effector as a fusion protein . construction of fusion proteins is within ordinary skill in the art . the antibodies disclosed herein can be used to treat various forms of cancer , e . g ., breast , ovarian , prostate , cervical , colorectal , lung ( e . g ., non - small cell lung cancer ), pancreatic , gastric , skin , kidney , head and neck , and schwannoma cancers . the cancer cells are exposed to a therapeutically effective amount of the antibody so as to inhibit or reduce proliferation of the cancer cell . in some embodiments , the antibodies inhibit cancer cell proliferation by at least 40 %, 50 %, 60 %, 70 %, 80 %, 90 %, 95 %, 98 %, 99 %, or 100 %. in some embodiments , the antibody inhibits or reduces proliferation of a tumor cell by inhibiting binding of human erbb3 to an erbb3 ligand , e . g ., neuregulin / heregulin especially nrgβ1 / nrg1 - β1 / nrgβ1 / hrgβ1 and nrgα1 / nrg1 - α1 / nrgα1 / hrgα1 . the antibody can be used in a method to inhibit tumor growth in a human patient . the method comprises administering to the patient a therapeutically effective amount of the antibody . cancers associated with erbb3 overexpression and / or activation include breast cancer , ovarian cancer , prostate cancer , cervical cancer , lung cancer ( e . g ., non - small cell lung cancer ), some forms of brain cancer ( e . g ., schwannoma ), melanomas , skin , kidney , and gastrointestinal cancers ( e . g ., colorectal , pancreatic , gastric , head and neck ). as used herein , “ treat , “ treating ” and “ treatment ” mean the treatment of a disease in a mammal , e . g ., in a human . this includes : ( a ) inhibiting the disease , i . e ., arresting its development ; and ( b ) relieving the disease , i . e ., causing regression of the disease state ; and ( c ) curing the disease . generally , a therapeutically effective amount of active component is in the range of 0 . 1 mg / kg to 100 mg / kg , e . g ., 1 mg / kg to 100 mg / kg , 1 mg / kg to 10 mg / kg . the amount administered will depend on variables such as the type and extent of disease or indication to be treated , the overall health of the patient , the in vivo potency of the antibody , the pharmaceutical formulation , and the route of administration . the initial dosage can be increased beyond the upper level in order to rapidly achieve the desired blood - level or tissue level . alternatively , the initial dosage can be smaller than the optimum , and the daily dosage may be progressively increased during the course of treatment . human dosage can be optimized , e . g ., in a conventional phase i dose escalation study designed to run from 0 . 5 mg / kg to 20 mg / kg . dosing frequency can vary , depending on factors such as route of administration , dosage amount and the disease being treated . exemplary dosing frequencies are once per day , once per week and once every two weeks . a preferred route of administration is parenteral , e . g ., intravenous infusion . formulation of monoclonal antibody - based drugs is within ordinary skill in the art . in some embodiments , the monoclonal antibody is lyophilized and reconstituted in buffered saline at the time of administration . for therapeutic use , an antibody preferably is combined with a pharmaceutically acceptable carrier . as used herein , “ pharmaceutically acceptable carrier ” means buffers , carriers , and excipients suitable for use in contact with the tissues of human beings and animals without excessive toxicity , irritation , allergic response , or other problem or complication , commensurate with a reasonable benefit / risk ratio . the carrier ( s ) should be “ acceptable ” in the sense of being compatible with the other ingredients of the formulations and not deleterious to the recipient . pharmaceutically acceptable carriers include buffers , solvents , dispersion media , coatings , isotonic and absorption delaying agents , and the like , that are compatible with pharmaceutical administration . the use of such media and agents for pharmaceutically active substances is known in the art . pharmaceutical compositions containing antibodies disclosed herein can be presented in a dosage unit form and can be prepared by any suitable method . a pharmaceutical composition should be formulated to be compatible with its intended route of administration . examples of routes of administration are intravenous ( iv ), intradermal , inhalation , transdermal , topical , transmucosal , and rectal administration . a preferred route of administration for monoclonal antibodies is iv infusion . useful formulations can be prepared by methods well known in the pharmaceutical art . for example , see remington &# 39 ; s pharmaceutical sciences , 18th ed . ( mack publishing company , 1990 ). formulation components suitable for parenteral administration include a sterile diluent such as water for injection , saline solution , fixed oils , polyethylene glycols , glycerine , propylene glycol or other synthetic solvents ; antibacterial agents such as benzyl alcohol or methyl parabens ; antioxidants such as ascorbic acid or sodium bisulfite ; chelating agents such as edta ; buffers such as acetates , citrates or phosphates ; and agents for the adjustment of tonicity such as sodium chloride or dextrose . for intravenous administration , suitable carriers include physiological saline , bacteriostatic water , cremophor eltm ( basf , parsippany , n . j .) or phosphate buffered saline ( pbs ). the carrier should be stable under the conditions of manufacture and storage , and should be preserved against microorganisms . the carrier can be a solvent or dispersion medium containing , for example , water , ethanol , polyol ( for example , glycerol , propylene glycol , and liquid polyetheylene glycol ), and suitable mixtures thereof . pharmaceutical formulations preferably are sterile . sterilization can be accomplished , for example , by filtration through sterile filtration membranes . where the composition is lyophilized , filter sterilization can be conducted prior to or following lyophilization and reconstitution . the following examples are merely illustrative and are not intended to limit the scope or content of the invention in any way . immunizations , fusions , and primary screens were conducted at maine biotechnology services inc . following the repetitive immunization multiple sites ( rimms ) protocol . three aj mice and three balb / c mice were immunized with recombinant human erbb3 / fc ( r & amp ; d systems , cat . no . 348 - rb ). two sets of immunization were performed with either cleaved rherbb3 ( immunization a ) or with cleaved rherbb3 cross - linked to its ligand , recombinant human nrg1 - β1 / hrg1 - β1 - egf domain ( r & amp ; d systems , cat . no . 396 - hb ) ( immunization b ). two aj mice per immunization with sera displaying high anti - erbb3 activity by enzyme linked immunosorbent assay ( elisa ) were chosen for subsequent fusion . spleens and lymph nodes from the appropriate mice were harvested . b - cells then were harvested and fused with a myeloma line . fusion products were serially diluted onto forty 96 - well plates to near clonality . a total of 5280 supernatants from the resulting fusions were screened for binding to recombinant rherbb3 / fc , using elisa . the same supernatants were also screened for their binding to human erbb3 overexpressed in cho cells ( by mesoscale electrochemiluminescence assay ). three hundred supernatants identified as containing antibodies against erbb3 were further characterized by in vitro biochemical and cell - based assays as discussed below . a panel of hybridomas was selected , and the hybridomas were subcloned and expanded . hybridoma cell lines were transferred to bioxcell ( formerly bio - express ) for antibody expression and purification by affinity chromatography on protein g resin under standard conditions . anti - herbb3 monoclonal antibody 04d01 was generated from immunization a described above . anti - herbb3 monoclonal antibodies 09d03 , 11g01 , 12a07 , 18h02 , 22a02 and 24c05 were generated from immunization b described above . the light - chain isotype and heavy chain isotype of each monoclonal antibody in example 1 was determined using the isostrip ™ mouse monoclonal antibody isotyping kit according the manufacturer &# 39 ; s instructions ( roche applied science ). all antibodies were determined to be kappa light chain and igg1 or igg2b igg heavy chain . the heavy and light chain variable regions of the mouse monoclonal antibodies were sequenced using 5 ′ race ( rapid amplification of cdna ends ). total rna was extracted from each monoclonal hybridoma cell line using the rneasy ® miniprep kit according to the vendor &# 39 ; s instructions ( qiagen ). full - length first strand cdna containing 5 ′ ends was generated using either the generacer ™ kit ( invitrogen ) or smarter ™ race cdna amplification kit ( clontech ) according to the manufacturer &# 39 ; s instructions using random primers for 5 ′ race . the variable regions of the kappa and heavy ( igg1 or igg2b ) igg chains were amplified by pcr , using kod hot start polymerase ( novagen ) or advantage 2 polymerase mix ( clontech ) according to the manufacturer &# 39 ; s instructions . for amplification of 5 ′ cdna ends in conjunction with the generacer ™ kit , the generacer ™ 5 ′ primer , 5 ′ cgactggagcacgaggacactga 3 ′ ( seq id no : 136 ) ( invitrogen ) was used as a 5 ′ primer . for amplification of 5 ′ cdna ends in conjunction with the smarter ™ race cdna amplification kit , the universal primer mix a primer ( clontech ), a mix of 5 ′ ctaatacgactcactatagggcaagcagtggtatcaacgcagagt 3 ′ ( seq id no : 137 ) and 5 ′ ctaatacgactcactatagggc 3 ′ ( seq id no : 138 ), was used as a 5 ′ primer . heavy chain variable regions were amplified using the above 5 ′ primers and a 3 ′ igg1 constant region specific primer , either 5 ′ tatgcaaggcttacaaccaca 3 ′ ( seq id no : 139 ) or 5 ′ gccagtggatagacagatgggggtgtcg 3 ′ ( seq id no : 140 ). igg2b sequences were amplified with either 5 ′ aggacaggggttgattgttga 3 ′ ( seq id no : 141 ), 5 ′ ggccagtggatagactgatgggggtgttgt 3 ′ ( seq id no : 142 ), or 5 ′ ggaggaaccagttgtatctccacaccca 3 ′ ( seq id no : 143 ). kappa chain variable regions were amplified with the above 5 ′ primers and a 3 ′ kappa constant region specific primer , either 5 ′ ctcattcctgttgaagctcttgacaat 3 ′ ( seq id no : 144 ) or 5 ′ cgactgaggcacctccagatgtt 3 ′ ( seq id no : 145 ). individual pcr products were isolated by agarose gel electrophoresis and purified using the qiaquick ® gel purification kit according to the manufacturer &# 39 ; s instructions ( qiagen ). the pcr products were subsequently cloned into the pcr ® 4blunt plasmid using the zero blunt ® topo ® pcr cloning kit according to the manufacturer &# 39 ; s instructions ( invitrogen ) and transformed into dh5 - α bacteria ( invitrogen ) through standard molecular biology techniques . plasmid dna isolated from transformed bacterial clones was sequenced using m13 forward ( 5 ′ gtaaaacgacggccagt 3 ′) ( seq id no : 146 ) and m13 reverse primers ( 5 ′ caggaaacagctatgacc 3 ′) ( seq id no : 147 ) by beckman genomics , using standard dideoxy dna sequencing methods to identify the sequence of the variable region sequences . the sequences were analyzed using vector nti software ( invitrogen ) and the imgt / v - quest software to identify and confirm variable region sequences . the nucleic acid sequences encoding and the protein sequences defining variable regions of the murine monoclonal antibodies are summarized below ( amino terminal signal peptide sequences are not shown ). cdr sequences ( kabat definition ) are shown in bold / underlined in the amino acid sequences . the amino acid sequences defining the immunoglobulin heavy chain variable regions for the antibodies produced in example 1 are aligned in fig2 . amino terminal signal peptide sequences ( for proper expression / secretion ) are not shown . cdr 1 , cdr 2 , and cdr 3 ( kabat definition ) are identified by boxes . fig3 shows an alignment of the separate cdr 1 , cdr 2 , and cdr 3 sequences for each antibody . the amino acid sequences defining the immunoglobulin light chain variable regions for the antibodies in example 1 are aligned in fig4 . amino terminal signal peptide sequences ( for proper expression / secretion ) are not shown . cdr 1 , cdr 2 and cdr 3 are identified by boxes . fig5 shows an alignment of the separate cdr 1 , cdr 2 , and cdr 3 sequences for each antibody . table 1 is a concordance chart showing the seq id no . of each sequence discussed in this example . to create the complete heavy or kappa chain antibody sequences , each variable sequence above is combined with its respective constant region . for example , a complete heavy chain comprises a heavy variable sequence followed by the murine igg1 or igg2b heavy chain constant sequence and a complete kappa chain comprises a kappa variable sequence followed by the murine kappa light chain constant sequence . the following sequences represent the actual or contemplated full length heavy and light chain sequences ( i . e ., containing both the variable and constant regions sequences ) for each antibody described in this example . signal sequences for proper secretion of the antibodies are also included at the 5 ′ end of the dna sequences or the amino terminal end of the protein sequences . the variable region sequences can be ligated to other constant region sequences , to produce active full length igg heavy and light chains . for convenience , table 4 provides a concordance chart showing the correspondence between the full length sequences of the antibodies discussed in this example with those presented in the sequence listing . the binding affinities and kinetics of the binding of monoclonal antibodies 04d01 , 09d03 , 11g01 , 12a07 , 18h02 , 22a02 and 24c05 to recombinant human erbb3 / fc fusion protein ( rherbb3 - fc ) were measured by surface plasmon resonance using a biacore ® t100 ( biacore ) instrument . rabbit anti - mouse iggs ( biacore , cat . no . br - 1008 - 38 ) were immobilized on carboxymethylated dextran cm4 sensor chips ( biacore , cat . no . br - 1005 - 34 ) by amine coupling ( biacore , cat . no . br - 1000 - 50 ) using a standard coupling protocol according to vendor &# 39 ; s instructions . the analyses were performed at 25 ° c ., using pbs ( invitrogen , cat . no . 14040 - 133 ) containing 0 . 05 % surfactant p20 ( biacore , cat . no . br - 1000 - 54 ) as running buffer . the antibodies were captured in individual flow cells at a flow rate of 10 μl / minute . injection time was varied for each antibody to yield an r max between 30 and 60 ru . buffer or rherbb3 - fc diluted in running buffer was injected sequentially over a reference surface ( no antibody captured ) and the active surface ( antibody to be tested ) for 300 seconds at 60 μl / minute . the dissociation phase was monitored for up to 3600 seconds . the surface was then regenerated with two 60 - seconds injection of 10 mm glycine - hcl , ph 1 . 7 ( made from glycine ph 1 . 5 ( biacore , cat . no . br - 1003 - 54 ) and ph 2 . 0 ( biacore , cat . no . br - 1003 - 55 )) at a flow rate of 60 μl / minute . the rherbb3 - fc concentration range tested was 0 . 125 nm to 20 nm . kinetic parameters were determined using the kinetic function of the biaevaluation software ( biacore ) with double reference subtraction . kinetic parameters for each antibody , k a ( association rate constant ), k d ( dissociation rate constant ) and k d ( equilibrium dissociation constant ) were determined . kinetic values of the monoclonal antibodies on rherbb3 - fc at 25 ° c . are summarized in table 5 . the data in table 5 demonstrate that the antibodies bind rherbb3 with a k d of about 350 pm or less , 250 pm or less , 200 pm or less , 150 pm or less , 100 pm or less , 50 pm or less , or 10 pm or less . in this example , the antibodies produced in example 1 were tested for ability to inhibit rherbb3 binding to nrg1 - β1 and nrg1 - al . the antibodies were tested by electrochemiluminescence ( ecl ) assay for inhibition of herbb3 binding to nrg1 - β1 . ma2400 96 - well standard binding plates ( meso scale discovery , cat . no . l15xa - 6 ) were coated with 50 μl of 0 . 5 μg / ml rherbb3 / fc ( r & amp ; d systems , cat . no . 348 - rb ) in pbs ( invitrogen , cat . no . 14040 - 133 ) for overnight at 4 ° c . with no agitation . the plates then were washed 3 times with pbs + 0 . 1 % tween20 ( sigma p5927 ) and blocked with 200 μl of pbs containing 5 % bsa ( sera care life sciences , cat . no . ap - 4510 - 80 ) for 1 . 5 hour at room temperature . after washing the plates 3 times with pbs , 25 μa of the antibody dilutions were added to the plates for another hour at room temperature with agitation . ligand nrg1 - β1 ( r & amp ; d systems , cat . no . 377 - hb , 26 kda ) was added to the wells at the final concentration of 0 . 25 μg / ml . the plates were washed three times with pbs and incubated with 25 μl of 1 μg / ml biotinylated antibody against human nrg1 - β1 ( r & amp ; d systems , cat . no baf377 ) preincubated for one hour with sulto - tag streptavidin ( meso scale discovery , cat . no r32ad - 5 ) for one hour at room temperature with agitation . the plates then were washed 3 times with pbs , and 150 μl of 1 × read buffer ( meso scale discovery , cat . no . r92tc - 1 ) was added to each well before the plates were analyzed on a sector ® imager 2400 ( meso scale discovery ) instrument . the interaction of nrg1 - β1 with erbb3 was inhibited by antibodies 04d01 , 12a07 , 18h02 , 22a02 and 24c05 ( fig6 a ). the interaction of nrg1 - β1 with rherbb3 was enhanced by antibody 09d03 , but not as well as by antibody 11g01 ( fig6 b ). the murine anti - human erbb3 antibody ic 50 values for neutralization of nrg1 - β1 binding to rherbb3 for the antibodies ( i . e ., 04d01 , 12a07 , 18h02 , 22a02 and 24c05 ) were calculated and are summarized in table 6 . the antibodies were tested by ecl assay for inhibition of herbb3 binding to the second erbb3 ligand , nrg1 - α1 . to assay inhibition of binding of nrg1 - al to rherbb3 , the same method used for nrg1 - β1 was used , except for the following changes : concentrations of plated rherbb3 / fc ( r & amp ; d 4518 - rb ) and of ligand nrg1 - α1 ( thermo scientific , rp - 317 - p1ax ) were 1 μg / ml and 1 . 5 μg / ml , respectively . the interaction of nrg1 - al with rherbb3 was inhibited by 11g01 , 12a07 , 18h02 , 22a02 , and 24c05 igg1 , and was enhanced by antibody 09d03 ( fig7 ). in this example , the antibodies produced in example 1 were tested for binding to the dimerization domain ( domain 2 ) of herbb3 - ecd . domain 2 of herbb3 ( 118 amino acids , position 210 - 327 ) was cloned in place of domain 2 of her2 ( 119 amino acids , position aa220 - 338 ) into the full - length her2 receptor . the hybrid construct her2 / 3d2 was cloned into plenti6 . 3 and packaged by transient transfection of 293t cells into a lentivirus using the virapower ™ lentiviral support kit ( invitrogen , cat . no . k497000 ). cho cells were infected with the lentivirus expressing the her2 / 3d2 hybrid protein . the binding of the anti - erbb3 hybridoma supernatants to her2 / 3d2 were tested on these engineered cho cells by ecl with sulfo - tagged anti - mouse antibodies . data on the binding of the hybridoma supernatants to the chimeric protein her2 / 3d2 expressed on the cell surface of cho cells are summarized in fig8 . these results show that antibodies 09d03 and 11g01 bound to the erbb3 domain 11 , aa210 - 327 . this example describes a characterization of the antibodies produced in example 1 for their ability to inhibit nrg1 - β1 dependent proliferation of cells . antibodies were tested in the baf / 3 cell system engineered to express both human her2 and erbb3 and in the human mcf7 breast cancer cells which naturally express both her2 and erbb3 and grow in response to nrg1 - β1 stimulation . baf / 3 cells were infected by two lentiviruses engineered to express human her2 or human erbb3 . infected cells were selected with blasticidin ( 15 μg / ml ; invitrogen , cat . no . r21001 ) and individual colonies were isolated and tested for expression of both receptors . her2 / erbb3 expressing clones were maintained in culture under blasticidin selection with [ 80 % rpmi medium 1640 ( gibco , cat . no . 11875 - 093 ), 10 % fetal bovine serum ( gibco , cat . no . 10438 - 026 ) and 10 % wehi cell conditioned media { 90 % iscove &# 39 ; s modified dulbecco &# 39 ; s medium ( gibco , cat . no . 12440053 ), 10 % fetal bovine serum ( gibco , cat . no . 10438 - 026 )+ 2 mm l - glutamine ( gibco , cat . no . 25030 - 081 )+ 0 . 0025 mm mercaptoethanol ( invitrogen , cat . no . 21985 - 023 )}]. to screen for antagonistic erbb3 antibodies , cells were rinsed with pbs , and grown in the absence of blasticidin and wehi conditioned media . assays were conducted in a 96 - well plate ( 5 , 000 cells / well ) in the presence of nrg1 - β1 ( 100 ng / ml ) and various concentrations of antibodies ( 0 . 018 - 5000 ng / ml in 100 μl final volume ). mtt ( 3 -( 4 , 5 - dimethylthiazol - 2 - yl )- 2 , 5 - diphenyltetrazolium bromide ) assays were conducted 3 - 4 days post nrg1 - β1 stimulation . an example of the dose - dependent inhibition of nrg1 - β1 dependent cell proliferation of her2 / erbb3 - baf / 3 by murine anti - human erbb3 antibodies is shown in fig9 . inhibition data of nrg1 - β1 dependent her2 / erbb3 - baf / 3 cell line proliferation with monoclonal antibodies ( i . e ., 04d01 , 09d03 , 11g01 , 12a07 , 18h02 , 22a02 and 24c05 ) are summarized in table 7 . mcf7 cells ( atcc , cat . no . htb - 22 ) were maintained as recommended by atcc . cells were plated at 5 , 000 cells / well in a 96 - well plate . cells were starved overnight in the absence of serum . the following day , nrg1 - β1 ( 40 ng / ml ) and various concentrations of antibodies ( 12 . 8 pg / ml - 20 μg / ml in 100 μl final volume ) were added to the cells . mtt ( 3 -( 4 , 5 - dimethylthiazol - 2 - yl )- 2 , 5 - diphenyltetrazolium bromide ) assays were conducted three days post nrg1 - β1 stimulation . an example of the dose - dependent inhibition of nrg1 - β1 dependent proliferation of mcf7 cells by murine anti - human erbb3 antibodies is shown in fig1 . inhibition data of nrg1 - β1 dependent mcf7 cell proliferation with antibodies 04d01 , 09d03 , 11g01 , 12a07 , 18h02 , 22a02 and 24c05 are summarized in table 8 . the antibodies produced in example 1 were also tested for their ability to inhibit proliferation of erbb3 expressing human cancer cells . breast cancer cells skbr - 3 overexpress her2 and are sensitive to her2 - specific inhibitory antibodies . skbr - 3 cells ( atcc , cat . no . htb - 30 ) were maintained as recommended by atcc . cells were plated at 5 , 000 cells / well in a 96 - well plate in the presence of 5 μg / ml of antibodies but without exogenous nrg1 - β1 . mtt ( 3 -( 4 , 5 - dimethylthiazol - 2 - yl )- 2 , 5 - diphenyltetrazolium bromide ) assays were conducted after three days in culture . an example of inhibition of cell proliferation of skbr - 3 cells by murine anti - human erbb3 antibodies is shown in fig1 . the results in fig1 show that antibodies 04d01 , 09d03 , 11g01 , 12a07 , 18h02 , 22a02 and 24c05 inhibited proliferation of skbr - 3 cells . this example describes a characterization of the antibodies produced in example 1 for their ability to inhibit nrg1 - β1 dependent phosphorylation of erbb3 and the downstream kinase akt , as the readout for pi3k activation . these antibodies were also tested for their ability to inhibit steady state phosphorylation of erbb3 and akt in exponentially growing cells . breast cancer cells skbr - 3 and mcf7 and prostate cancer cells du145 were maintained as recommended by atcc . cells were starved overnight in 0 % fbs , treated for one hour with 5 μg / ml of antibody followed by nrg1 - β1 stimulation . lysates were either analyzed by elisa with the phospho - erbb3 kit from r & amp ; d systems ( cat . no dyc1769 ) or with the phospho - akt elisa kit from cell signaling ( cat . no 7143 ). an example of the inhibition of the nrg1 - β1 induced phosphorylation of erbb3 in skbr - 3 cells by murine anti - human erbb3 antibodies is shown in fig1 . the results in fig1 demonstrated that antibodies 04d01 , 09d03 , 11g01 , 12a07 , 18h02 , 22a02 and 24c05 inhibited at least 50 % of the phosphorylation of erbb3 induced by nrg1 - β1 in skbr - 3 cells . an example of the inhibition of the nrg1 - β1 induced phosphorylation of akt in mcf7 and du145 cells by murine anti - human erbb3 antibodies is shown in fig1 a and fig1 b , respectively . the results in fig1 a and 13b demonstrated that antibodies 04d01 , 09d03 , 11g01 , 12a07 , 18h02 , 22a02 and 24c05 inhibited at least 80 % of the phosphorylation of akt in response to the nrg1 - β1 in both mcf7 and du145 cells . the capacity of the anti - erbb3 antibodies to inhibit the steady state phosphorylation status of erbb3 and akt in a breast cancer cell line skbr - 3 and a pancreatic cancer cell line bxpc3 were tested by treating these exponentially growing cells for one hour in presence of antibodies at 5 μg / ml . western blot analysis of these experiments demonstrated that antibodies 04d01 , 09d03 , 11g01 , 12a07 , 18h02 , 22a02 and 24c05 inhibited the steady state level of phosphorylation of akt and erbb3 in both skbr - 3 and bxpc3 cells . in this example , the antibodies produced in example 1 were tested for their ability to inhibit nrg1 - β1 dependent phosphorylation of egfr in the ovarian cancer cell line nci / adr - res . nci / adr - res cells ( dtp / dctd nci tumor repository ) were starved overnight in 0 % fbs , pre - treated with antibody ( 5 μg / ml ) for one hour followed by nrg1 - β1 ( 20 ng / ml ) stimulation for 15 minutes . the phosphorylation of egfr on tyrosine 1068 was analyzed by western blot . the results of this experiment demonstrated that antibodies 04d01 , 09d03 , 11g01 , 12a07 , 18h02 , 22a02 and 24c05 inhibited the phosphorylation of egfr in response to the nrg1 - β1 in nci / adr - res cells . in this example , the antibodies produced in example 1 were tested for their ability to inhibit egf dependent phosphorylation of erbb3 in the egfr overexpressing , epidermoid cancer cell line a431 . a431 cells ( atcc , cat . no crl - 1555 ) were starved overnight in 0 % fbs , pre - treated with antibody ( 5 μg / ml ) for one hour followed by egf ( r & amp ; d systems , cat . no . 236 - eg ) ( 50 ng / ml ) stimulation for 15 minutes . the phosphorylation of erbb3 was analyzed by western blot . the results of this experiment demonstrated that antibodies 04d01 , 09d03 , 12a07 , 18h02 , 22a02 and 24c05 inhibited to various extents the phosphorylation of erbb3 in response to the egf in a431 cells . this example describes a characterization of the antibodies produced in example 1 for their ability to inhibit the formation of the her2 / erbb3 dimer in response to nrg1 - β1 in skbr - 3 cells . breast cancer cells skbr - 3 were starved overnight in 0 % fbs , treated for one hour with 5 μg / ml of antibody followed by nrg1 - β1 stimulation ( 30 ng / ml , 30 min ). lysates were immunoprecipitated with anti - her2 antibody ( r & amp ; d systems , cat . no . baf1129 ) and analyzed by western blot with polyclonal anti - erbb3 antibody ( santa cruz , cat . no . sc285 ). the results of this experiment demonstrated that antibodies 04d01 , 09d03 , 11g01 , 12a07 , 18h02 , 22a02 and 24c05 inhibited nrg1 - β1 - induced her2 / erbb3 dimer formation in skbr - 3 cells . the ability of murine monoclonal antibodies produced in example 1 to inhibit tumor growth was tested in a pancreatic bxpc3 xenograft model . human pancreatic bxpc3 cells were grown in culture in 37 ° c . in an atmosphere containing 5 % c02 , using rmpi medium containing 10 % fetal bovine serum . bxpc3 cells were inoculated subcutaneously into the flank of 8 - week old female cb . 17 scid mice ( taconic labs ) with 10 × 10 6 cells per mouse in 50 % matrigel ( bd biosciences , cat no . 356237 ). tumor measurements were taken twice weekly using vernier calipers . tumor volume was calculated using the formula : width × width × length / 2 . when tumors reached approximately 200 mm 3 , the mice were randomized into 9 groups of 10 mice each . one group received pbs and another received human igg control ( huigg ). each of the other eight groups received one of the antibody , 04d01 , 09d03 , 18h02 , 11g01 , 24c05 , 22a02 , or 12a07 . all antibodies were dosed at 20 mg / kg body weight , twice per week , by intra - peritoneal injection for 6 weeks . tumor volumes and mouse body weights were recorded twice per week . tumor growth inhibition was analyzed using anova and is expressed as percent inhibition compared to the pbs control . the results in fig1 show that antibody 24c05 inhibited tumor growth by 76 % in this model ( p & lt ; 0 . 001 ). antibodies 04d01 , 18h02 and 11g01 also inhibited tumor growth in this model at 64 %, 71 %, and 72 %, respectively ( p & lt ; 0 . 001 ). antibodies 12a07 and 22a02 demonstrated the least activity , i . e ., near 40 % tumor growth inhibition , while antibody 09d03 gave 60 % tumor growth inhibition in this model . this example describes the humanization of the murine antibody designated 24c05 , and the characterization of the resulting humanized antibodies . the humanized anti - erbb3 antibodies were designed using the superhumanization ™ method ( arana therapeutics ltd . and hwang , w . y . et al . ( 2005 ) methods 36 : 35 - 42 ) or the cdr grafting method with back mutations ( some human framework residues were changed to murine residues ) ( see e . g ., u . s . pat . nos . 5 , 530 , 101 ; 5 , 693 , 761 ; 5 , 693 , 762 ; 5 , 585 , 089 ; 6 , 180 , 370 ; 7 , 022 , 500 ). with the exception of heavy chain cdr1 , the kabat cdr definitions were used for cdr grafting onto human frameworks . a combination of kabat and chothia definitions were used for grafting heavy cdr1 . the designed amino acid sequences were converted to codon - optimized dna sequences and synthesized by dna2 . 0 , inc . to include ( in the following order ): 5 ′ hindiii restriction site , kozak consensus sequence , amino terminal signal sequence , humanized variable region , human igg1 or kappa constant region , stop codon , and a 3 ′ ecori restriction site . additionally , one humanized heavy chain , sh24c05 hv3 - 11 heavy igg1 , was mutated using overlap extension pcr to enhance humanization , resulting in the sh24c05 hv3 - 11 n62s heavy chain igg1 . a human igg2 version of the sh24c05 hv3 - 11 n62s heavy chain was also constructed . the anti - erbb3 antibody chains humanized according to the superhumanization ™ method , as described herein , are designated with the prefix “ sh ” before the antibody chain name . the anti - erbb3 antibody chains humanized by the cdr grafting method with back mutations , as described herein , are designated with the prefix “ hu ” before the antibody chain name . chimeric ( murine variable region and human constant region ) 24c05 heavy ( human igg1 ) and light ( human kappa ) chains were also constructed . the murine variable regions were fused to the human constant region using overlap extension pcr , including ( in the following order ): 5 ′ hindiii restriction site , kozak consensus sequence , amino terminal signal sequence , mouse variable region , human igg1 or kappa constant region , stop codon , and 3 ′ ecori restriction site . the humanized and chimeric heavy chains were subcloned into pee6 . 4 ( lonza biologics ) via hindiii and ecori sites using in - fusion ™ pcr cloning ( clontech ). the humanized and chimeric kappa light chains were subcloned into pee14 . 4 ( lonza biologics ) via hindiii and ecori sites using in - fusion ™ pcr cloning . humanized antibody chains or chimeric antibody chains were transiently transfected into 293t cells to produce antibody . antibody was either purified or used in cell culture media supernatant for subsequent in vitro analysis . binding of the chimeric and humanized antibodies to human erbb3 was measured as described below . the results are summarized in table 15 . additionally , some humanized antibody heavy and light chain combinations were stably expressed in chok1sv cells using the gs system ™ ( lonza biologics ) in order to produce large quantities of purified humanized antibody . a single expression vector was constructed by combining pee6 . 4 and pee14 . 4 based vectors . first , pee6 . 4 containing full length humanized heavy chain cdna was digested with noti and sali to isolate the hcmv - mie promoter + full length humanized heavy chain cdna + sv40 polya fragment . this fragment was inserted into the pee14 . 4 vector already containing full length humanized light chain cdna via noti / sali sites , thus creating an expression vector that simultaneously expresses heavy and light chains . the combined heavy and light chain vector was linearized and transfected into chok1sv cells . stable clones were selected in the presence of methionine sulfoximine . each of the possible combinations of the humanized immunoglobulin heavy chain and immunoglobulin light chain variable regions are set forth below in table 9 . the nucleic acid sequences encoding and the protein sequences defining variable regions of the humanized 24c05 antibodies are summarized below ( amino terminal signal peptide sequences are not shown ). cdr sequences ( kabat definition ) are shown in bold and are underlined in the amino acid sequences . the amino acid sequences defining the immunoglobulin heavy chain variable regions for the antibodies produced in example 12 are aligned in fig1 . amino terminal signal peptide sequences ( for proper expression / secretion ) are not shown . cdr 1 , cdr 2 , and cdr 3 ( kabat definition ) are identified by boxes . the amino acid sequences defining the immunoglobulin light chain variable regions for the antibodies in example 12 are aligned in fig1 . amino terminal signal peptide sequences ( for proper expression / secretion ) are not shown . cdr 1 , cdr 2 and cdr 3 are identified by boxes . table 10 is a concordance chart showing the seq id no . of each sequence discussed in this example . to create the complete chimeric and humanized heavy or kappa chain antibody sequences , each variable sequence above is combined with its respective human constant region . for example , a complete heavy chain comprises a heavy variable sequence followed by a human igg1 heavy chain constant sequence or a human igg2 heavy chain constant sequence . a complete kappa chain comprises a kappa variable sequence followed by the human kappa light chain constant sequence . the following sequences represent the actual or contemplated full length heavy and light chain sequences ( i . e ., containing both the variable and constant regions sequences ) for each antibody described in this example . signal sequences for proper secretion of the antibodies are also included at the 5 ′ end of the dna sequences or the amino terminal end of the protein sequences . it is also contemplated herein that the variable region sequences can be ligated to other constant region sequences to produce active full length igg heavy and light chains . for convenience , table 13 provides a concordance chart showing the seq id no . of each sequence discussed in this example . table 14 below shows antibodies containing chimeric immunoglobulin heavy and light chains and each of the possible combinations of the full - length humanized immunoglobulin heavy and light chains . chimeric 24c05 = full length chimeric 24c05 heavy chain ( mouse variable region and human igg1 constant region ) ( seq id no : 182 ) plus full length chimeric 24c05 light chain ( mouse variable region and human kappa constant region ) ( seq id no : 184 ) four of the possible antibody constructs containing the full length immunoglobulin heavy and light chains containing humanized variable regions are designated below : sh24c05 - 25 n62s igg1 = humanized sh24c05 hv3 - 11 n62s heavy chain variable region and human igg1 constant region ( seq id no : 190 ) plus sh24c05 kv1 - 16 light chain variable region and human kappa constant region ( seq id no : 204 ) sh24c05 - 25 n62s igg2 = humanized sh24c05 hv3 - 11 n62s heavy chain variable region and human igg2 constant region ( seq id no : 192 ) plus sh24c05 kv1 - 16 light chain variable region and human kappa constant region ( seq id no : 204 ) sh24c05 - 31 n62s igg1 = humanized sh24c05 hv3 - 11 n62s heavy chain variable region and human igg1 constant region ( seq id no : 190 ) plus sh24c05 kv1 - 17 light chain variable region and human kappa constant region ( seq id no : 206 ) sh24c05 - 31 n62s igg2 = humanized sh24c05 hv3 - 11 n62s heavy chain variable region and human igg2 constant region ( seq id no : 192 ) plus sh24c05 kv1 - 17 light chain variable region and human kappa constant region ( seq id no : 206 ) the binding affinities and kinetics of interaction of monoclonal antibodies produced in example 12 against recombinant human erbb3 monomeric protein ( cleaved rherbb3 ) were measured by surface plasmon resonance using a biacore ® t100 ( biacore ) instrument . monomeric erbb3 was obtained by protease cleavage of rherbb3 - fc ( r & amp ; d systems , cat . no . 348 - rb ). goat anti - human igg fc ( jackson immunoresearch , catalog no . 109 - 005 - 098 ) was immobilized on carboxymethylated dextran cm4 sensor chips ( biacore , catalog no . br - 1005 - 34 ) by amine coupling ( biacore , catalog no . br - 1000 - 50 ) using a standard coupling protocol according to the vendor &# 39 ; s instructions . the analyses were performed at 37 ° c . using pbs ( invitrogen , catalog no . 14040 - 133 ) containing 0 . 05 % surfactant p20 ( biacore , catalog no . br - 1000 - 54 ) as running buffer . the antibodies were captured in individual flow cells at a flow rate of 60 μl / minute . injection time was varied for each antibody to yield an r max between 30 and 60 ru . buffer or cleaved rherbb3 diluted in running buffer was injected sequentially over a reference surface ( no antibody captured ) and the active surface ( antibody to be tested ) for 300 seconds at 60 μl / minute . the dissociation phase was monitored for up to 1200 seconds . the surface was then regenerated with two 60 second injections of glycine ph 2 . 25 ( made from glycine ph 2 . 0 ( biacore , catalog no . br - 1003 - 55 ) and ph 2 . 5 ( biacore , catalog no . br - 1003 - 56 )) at 60 μl / minute . for the initial screening , only one or two concentrations of cleaved rherbb3 were tested , typically 5 . 0 and 1 . 25 nm ( results are summarized in table 15 ). kinetic parameters were determined using the kinetic function of the biaevaluation software ( biacore ) with double reference subtraction . kinetic parameters for each antibody , k a ( association rate constant ), k d ( dissociation rate constant ) and k d ( equilibrium dissociation constant ) were determined . the initial monoclonal antibodies were screened using cell culture media supernatant containing secreted antibody , and kinetic values of the monoclonal antibodies on cleaved rherbb3 at 37 ° c . are summarized in table 15 . the results in table 15 demonstrate that the chimeric and each of the humanized 24c05 antibodies have fast association rates ( k a ), very slow disassociation rates ( k d ) and very high affinities ( k d ). in particular , the antibodies have affinities ranging from about 87 pm to about 1 nm . the binding affinities and kinetics of certain purified monoclonal antibodies were also determined . to further characterize certain antibodies , the surface plasmon resonance experiments described above were conducted using concentrations of cleaved rherbb3 between 0 . 3125 nm and 5 . 0 nm ( a 2 - fold serial dilution ). the kinetic values of certain purified monoclonal antibodies ( i . e ., sh24c05 - 1 , sh24c05 - 25 , sh24c05 - 25 n62s igg1 , sh24c05 - 25 n62s igg2 , sh24c05 - 31 , sh24c05 - 31 n62s igg1 , and sh24c05 - 31 n62s igg2 ) on cleaved rherbb3 at 37 ° c . are summarized in table 16 . three human antibodies that inhibit the function of human erbb3 were constructed and expressed using published information . one antibody , referred to as ab # 6 , was constructed as a human igg2 / lambda antibody based the disclosure of schoeberl et al ., us 2009 / 0291085 ( merrimack pharmaceuticals , inc .). two additional antibodies , referred to as u1 - 53 and u1 - 59 , were constructed as human igg1 / kappa antibodies based on the disclosure of rothe et al ., us 2008 / 0124345 ( u3 pharma ag and amgen , inc .). kinetic parameters for the ab # 6 , u1 - 53 , and u1 - 59 antibodies were determined by biacore at 37 ° c . using cleaved rherbb3 ( monomer ) as described above ( see section b . binding affinities of humanized and chimeric anti - erbb3 monoclonal antibodies ). both biacore sensorgrams ( fig1 ) and kinetic values ( table 17 ) are displayed for each antibody . the results in table 17 demonstrate that the overall equilibrium dissociation constant ( k d ) for the sh24c05 - 31 n62s igg1 ( 76 pm ) was smaller ( i . e ., higher affinity ) than the k d for the ab # 6 and u1 - 59 antibodies ( 230 pm ( p & lt ; 0 . 01 ) and 530 pm ( p & lt ; 0 . 0005 ), respectively ). the equilibrium dissociation constant ( k d ) for u1 - 53 could not determined because of poor curve fits ( see fig1 , which shows a fast k off rate of u1 - 53 ). the k d of ab # 6 , u1 - 53 , and u1 - 59 antibodies can also be compared with other humanized 24c05 variants by comparing tables 16 and 17 . therefore , the affinity for sh24c05 - 31 n62s igg1 is significantly higher than the affinity of ab # 6 and u1 - 59 as disclosed herein . in this example , the humanized antibodies produced in example 12 were tested for their ability to inhibit rherbb3 binding to nrg1 - β1 by ecl assay . multi - array 96 - well standard binding plates ( meso scale discovery , cat . no . l15xa - 3 ) were coated with 50 μl of 0 . 5 μg / ml rherbb3 / fc ( r & amp ; d systems , cat . no . 348 - rb ) in pbs ( invitrogen , cat . no . 14040 - 133 ) for one hour at room temperature with no agitation . the plates then were washed three times with pbs + 0 . 1 % tween20 ( sigma p5927 ) and blocked with 200 μl of 100 % horse serum , heat inactivated ( gibco , cat . no . 26050 - 088 ) for 1 . 5 hours at room temperature . after washing the plates three times with pbs + 0 . 1 % tween , 25 μa of the antibody dilutions were added to the plates for another hour at room temperature with agitation . ligand nrg1 - β1 ( r & amp ; d systems , cat . no . 377 - hb , 26 kda ) was added to the wells at a final concentration of 0 . 25 μg / ml . the plates were washed three times with pbs + 0 . 1 % tween and incubated with 25 μl of 1 μg / ml biotinylated antibody against human nrg1 - β1 ( r & amp ; d systems , cat . no baf377 ) preincubated for one hour with sulto - tag streptavidin ( meso scale discovery , cat . no r32ad - 5 ) for one hour at room temperature with agitation . the plates then were washed three times with pbs + 0 . 1 % tween , and 150 μl of 1 × read buffer ( meso scale discovery , cat . no . r92tc - 1 ) was added to each well before the plates were analyzed on a sector ® imager 2400 ( meso scale discovery ) instrument . the interaction of nrg1 - β1 with rherbb3 was inhibited by antibodies sh24c05 - 25 n62s - igg1 , sh24c05 - 25 n62s - igg2 , sh24c05 - 31 n62s - igg1 , and sh24c05 - 31 n62s - igg2 ( fig1 a ). the ab # 6 igg2 antibody as described in schoeberl et al . ( supra ) and the u1 - 53 and u1 - 59 antibodies as described in rothe et al . ( supra ) were also tested for their ability to inhibit erbb3 binding to nrg1 - β1 . as shown in fig1 b , each of the ab # 6 igg2 , u1 - 53 , and u1 - 59 antibodies inhibited erbb3 binding to nrg1 - β1 . the ic 50 values for neutralization of nrg1 - β1 binding to herbb3 for the humanized 24c05 antibodies ( i . e ., sh24c05 - 25 n62s - igg1 , sh24c05 - 25 n62s - igg2 , sh24c05 - 31 n62s - igg1 , and sh24c05 - 31 n62s - igg2 ) were calculated and are summarized in table 18 . the ic so values for the nrg1 - β1 neutralization activity of the anti - erbb3 human antibodies ab # 6 igg2 , u1 - 53 and u1 - 59 are also shown in table 18 . the results in table 18 demonstrate that antibodies sh24c05 - 25 n62s - igg1 , sh24c05 - 25 n62s - igg2 , sh24c05 - 31 n62s - igg1 , and sh24c05 - 31 n62s - igg2 efficiently neutralized nrg1 - β1 binding to rherbb3 . while the anti - erbb3 human antibodies ab # 6 igg2 , u1 - 53 and u1 - 59 also showed neutralization activity , the humanized sh24c05 antibodies ( i . e ., sh24c05 - 25 n62s - igg1 , sh24c05 - 25 n62s - igg2 , sh24c05 - 31 n62s - igg1 , and sh24c05 - 31 n62s - igg2 ) had superior neutralization capacity than u1 - 59 or ab # 6 igg2 . in this example , the humanized antibodies produced in example 12 were tested for their ability to inhibit nrg1 - β1 dependent proliferation of cells in the baf / 3 cell system engineered to express both human her2 and erbb3 . baf / 3 cells expressing her2 and erbb3 receptors as described in example 6 were treated with anti - erbb3 antibodies in the absence of wehi conditioned media but in the presence of nrg1 - β1 ( 100 ng / ml ). assays were conducted in a 96 - well plate ( 5 , 000 cells / well ) in the presence of nrg1 - β1 ( 100 ng / ml ) and various concentrations of antibodies ( 0 . 018 - 5000 ng / ml in 100 μl of final volume ). mtt ( 3 -( 4 , 5 - dimethylthiazol - 2 - yl )- 2 , 5 - diphenyltetrazolium bromide ) assays were conducted 3 - 4 days post nrg1 - β1 stimulation . the results demonstrate that sh24c05 - 25 n62s - igg1 , sh24c05 - 25 n62s - igg2 , sh24c05 - 31 n62s - igg1 , and sh24c05 - 31 n62s - igg2 inhibited nrg induced her2 / erbb3 - baf / 3 cell proliferation in a dose dependent manner ( fig1 a ). the ic 50 values for the inhibition of nrg1 - β1 dependent her2 / erbb3 - baf / 3 cell line proliferation with the humanized 24c05 antibodies ( i . e ., sh24c05 - 25 n62s - igg1 , sh24c05 - 25 n62s - igg2 , sh24c05 - 31 n62s - igg1 , sh24c05 - 31 n62s - igg2 ) were calculated and are summarized in table 19 . the inhibitory activity of anti - erbb3 ab # 6 igg2 , u1 - 53 and u1 - 59 antibodies were also tested in the nrg1 - β1 dependent her2 / erbb3 - baf / 3 cells proliferation assay . as shown in fig1 b , the results demonstrate that the ab # 6 igg2 , u1 - 53 and u1 - 59 antibodies inhibited nrg induced her2 / erbb3 - baf / 3 cell proliferation in a dose dependent manner . inhibition data of nrg1 - β1 dependent her2 / erbb3 - baf / 3 cell proliferation with antibodies ab # 6 igg2 , u1 - 53 and u1 - 59 are summarized in table 19 . the results in table 19 demonstrate that antibodies ab # 6 igg2 , u1 - 53 , and u1 - 59 inhibited nrg1 - β1 - induced proliferation of her2 / erbb3 - baf / 3 cells . a comparison of the inhibitory activity of the tested anti - erbb3 antibodies in the nrg1 - β1 dependent her2 / erbb3 - baf / 3 cells proliferation assay indicates that the inhibitory activity of the humanized sh24c05 antibodies is superior to the inhibitory activity of the ab # 6 igg2 , u1 - 53 and u1 - 59 antibodies ( e . g ., the ic 50 was 0 . 1245 nm for sh24c05 - 31 n62s - igg1 compared to 0 . 8128 nm for u1 - 53 ). this example describes a characterization of the humanized antibodies produced in example 12 for their ability to degrade total erbb3 and inhibit phosphorylation of erbb3 in exponentially growing skbr - 3 cells . the breast cancer skbr - 3 cells were maintained as recommended by atcc . cells maintained in full serum condition were treated for 1 , 2 , 4 or 6 hours with 40 μg / ml of anti - erbb3 antibody ( i . e ., sh24c05 - 25 n62s - igg1 , sh24c05 - 25 n62s - igg2 , sh24c05 - 31 n62s - igg1 , and sh24c05 - 31 n62s - igg2 ). lysates were either analyzed by elisa with the total - erbb3 and the phospho - erbb3 kit from r & amp ; d systems ( cat . no dyc234 and cat . no dyc1769 , respectively ). the results demonstrate that anti - erbb3 antibodies sh24c05 - 25 n62s - igg1 , sh24c05 - 25 n62s - igg2 , sh24c05 - 31 n62s - igg1 , and sh24c05 - 31 n62s - igg2 inhibit at least 50 % of the phosphorylation of erbb3 in exponentially growing skbr - 3 cells ( fig2 ). the results also demonstrate that anti - erbb3 antibodies sh24c05 - 25 n62s - igg1 , sh24c05 - 25 n62s - igg2 , sh24c05 - 31 n62s - igg1 , and sh24c05 - 31 n62s - igg2 degraded at least 50 % of the total erbb3 receptor present in exponentially growing skbr - 3 cells ( fig2 ). the ability of the humanized monoclonal antibodies produced in example 12 to inhibit tumor growth were tested in a bxpc3 pancreatic xenograft model . human pancreatic bxpc3 cells were grown in culture in 37 ° c . in an atmosphere containing 5 % c02 , using rmpi medium containing 10 % fetal bovine serum . bxpc3 cells were inoculated subcutaneously into the flank of 8 - week old female cb . 17 scid mice ( taconic labs ) with 10 × 10 6 cells per mouse in 50 % matrigel ( bd biosciences , cat no . 356237 ). tumor measurements were taken twice weekly using vernier calipers . tumor volume was calculated using the formula : width × width × length / 2 . when tumors reached approximately 200 mm 3 , the mice were randomized into 8 groups of 10 mice each . one group received pbs , another received huigg control , and another received muigg control . each of the remaining five groups received one of the antibodies ( i . e ., murine 24c05 , sh24c05 - 25 n62s - igg1 , sh24c05 - 25 n62s - igg2 , sh24c05 - 31 n625 - igg1 or sh24c05 - 31 n62s - igg2 ). all of the antibodies were dosed at 2 mg / kg body weight , twice per week , by intra - peritoneal injection for 7 weeks . tumor volumes and mouse body weights were recorded twice per week . tumor growth inhibition was analyzed using anova and is expressed as percent inhibition compared to the pbs control . the tested humanized antibodies were active in vivo . all four humanized anti - erbb3 antibodies had similar efficacy in the bxpc3 model when dosed at 2 mg / kg , ranging from 75 - 80 % tumor growth inhibition ( p & lt ; 0 . 001 ) ( i . e ., sh24c05 - 25 n62s - igg1 , 75 %; sh24c05 - 25 n62s - igg2 , 76 %; sh24c05 - 31 n62s - igg1 , 79 %; and sh24c05 - 31 n62s - igg2 , 80 %) at day 28 of the study ( fig2 ). the murine antibody demonstrated 65 % tumor growth inhibition in this study ( p & lt ; 0 . 05 ). these results suggest similar potency and activity of the four humanized antibodies in this model . the ability of the humanized monoclonal antibodies u1 - 53 , u1 - 59 , and ab # 6 igg2 to inhibit tumor growth were also tested in a bxpc3 xenograft model . using the protocol described above , bxpc3 tumors were generated in cb . 17 scid mice . when tumors reached approximately 200 mm 3 , the mice were randomized into 11 groups of 10 mice each . one group received pbs and another received huigg control . each of the other nine groups received one of the humanized antibodies ( i . e ., sh24c05 - 31 n62s - igg1 , u1 - 53 , u1 - 59 , or ab # 6 igg2 ). the antibodies were dosed either at 0 . 5 mg / kg , 1 mg / kg , or 5 mg / kg body weight , twice per week , by intra - peritoneal injection for 7 weeks . tumor volumes and mouse body weights were recorded twice per week . tumor growth inhibition was analyzed using anova and is expressed as percent inhibition compared to the pbs control . tumor growth inhibition data determined at day 29 following treatment with one of the humanized antibodies ( i . e ., sh24c05 - 31 n62s - igg1 , u1 - 59 , or ab # 6 igg2 ) is shown in table 20 . the results demonstrate that sh24c05 - 31 n62s - igg1 showed the greatest tumor growth inhibition by day 29 ( 76 . 5 %, p & lt ; 0 . 001 ) at a dose of 5 mg / kg in the bxpc3 pancreatic xenograft model . the u1 - 59 and ab # 6 igg2 antibodies demonstrated approximately 60 % and 41 % tumor growth inhibition at a dose of 5 mg / kg in the bxpc3 model , respectively ( p & lt ; 0 . 001 ). the results also demonstrate that sh24c05 - 31 n62s - igg1 showed the greatest tumor growth inhibition by day 29 at a dose of 0 . 5 mg / kg ( 63 . 3 %, p & lt ; 0 . 001 ) and at a dose of 1 mg / kg ( 75 . 0 %, p & lt ; 0 . 001 ) in the bxpc3 pancreatic xenograft model . the u1 - 59 and ab # 6 igg2 antibodies demonstrate approximately 33 % ( p & lt ; 0 . 01 ) and 31 % ( p & lt ; 0 . 05 ) tumor growth inhibition at a dose of 0 . 5 mg / kg in the bxpc3 model , respectively . the u1 - 59 and ab # 6 igg2 antibodies demonstrated approximately 53 % ( p & lt ; 0 . 001 ) and 2 % ( not significant ) tumor growth inhibition at a dose of 1 . 0 mg / kg in the bxpc3 model , respectively . the ability of the humanized monoclonal antibodies produced in example 12 to inhibit tumor growth was tested in a calu - 3 non - small cell lung cancer xenograft model . the ability of the humanized monoclonal antibodies u1 - 59 and ab # 6 igg2 , as described in example 12 , to inhibit tumor growth were also tested in the same model . human non - small cell lung cancer calu - 3 cells were grown in culture in 37 ° c . in an atmosphere containing 5 % c02 , using emem medium containing 10 % fetal bovine serum . calu - 3 cells were inoculated subcutaneously into the flank of 8 - week old female ncr nude mice ( taconic labs ) with 10 × 10 6 cells per mouse in 50 % matrigel ( bd biosciences , cat no . 356237 ). tumor measurements were taken twice weekly using vernier calipers . tumor volume was calculated using the formula : width × width × length / 2 . when tumors reached approximately 200 mm 3 , the mice were randomized into 11 groups of 10 mice each . one group received pbs and another received muigg control . each of the other nine groups received one of the humanized antibodies ( i . e ., sh24c05 - 31 n62s - igg1 , u1 - 59 , or ab # 6 igg2 ) at a dose of either 5 mg / kg , 10 mg / kg or 20 mg / kg body weight , twice per week , by intra - peritoneal injection for 4 weeks . tumor volumes and mouse body weights were recorded twice per week . tumor growth inhibition was analyzed using anova and is expressed as percent inhibition compared to the pbs control . tumor growth inhibition data determined at day 26 following treatment with one of the humanized antibodies ( i . e ., sh24c05 - 31 n62s - igg1 , u1 - 59 , or ab # 6 igg2 ) is shown in table 21 . the results using the calu - 3 non - small cell lung cancer xenograft model demonstrate that sh24c05 - 31 n62s - igg1 showed the greatest tumor growth inhibition by day 26 at all doses tested ( i . e ., 5 mg / kg , 10 mg / kg , and 20 mg / kg of body weight ). for example , at the 10 mg / kg dose , sh24c05 - 31 n62s - igg1 showed the greatest tumor growth inhibition by day 26 ( 62 %, p & lt ; 0 . 001 ) when compared to ab # 6 igg2 ( 36 %, ns ) or u1 - 59 ( 57 %, p & lt ; 0 . 001 ). at the 20 mg / kg dose , sh24c05 - 31 n62s - igg1 also showed the greatest tumor growth inhibition by day 26 ( 69 %, p & lt ; 0 . 001 ) when compared to ab # 6 igg2 ( 48 %, p & lt ; 0 . 001 ) or u1 - 59 ( 58 %, p & lt ; 0 . 001 ). the ability of the humanized monoclonal antibodies produced in example 12 to inhibit tumor growth were tested in a mda - mb - 453 breast xenograft model ( which is a her2 positive breast model ). the ability of the humanized monoclonal antibodies u1 - 59 and ab # 6 igg2 , as described in example 12 , to inhibit tumor growth were also tested in the same model . human breast mda - mb - 453 cells were grown in culture in 37 ° c . in an atmosphere containing 0 % c02 , using leibovitz atcc medium ( cat no . 30 - 2008 ) containing 10 % fetal bovine serum . mda - mb - 453 cells were inoculated subcutaneously into the flank of 8 - week old female nod scid mice ( taconic labs ) with 20 × 10 6 cells per mouse in 50 % matrigel ( bd biosciences , cat no . 356237 ). tumor measurements were taken twice weekly using vernier calipers . tumor volume was calculated using the formula : width × width × length / 2 . when tumors reached approximately 200 mm 3 , the mice were randomized into 7 groups of 10 mice each . one group received pbs and another received huigg control . each of the other nine groups received one of the humanized antibodies ( i . e ., sh24c05 - 31 n62s - igg1 , u1 - 59 , or ab # 6 igg2 ). sh24c05 - 31 n625 - igg1 was dosed either at 5 mg / kg , 10 mg / kg , or 20 mg / kg body weight , twice per week , by intra - peritoneal injection for more than 10 weeks ; u1 - 59 , or ab # 6 were dosed at 10 mg / kg with the same frequency . tumor volumes and mouse body weights were recorded twice per week . tumor growth inhibition was analyzed using anova and is expressed as percent inhibition compared to the pbs control . tumor growth inhibition data determined at day 71 following treatment with one of the humanized antibodies ( i . e ., sh24c05 - 31 n62s - igg1 , u1 - 59 , or ab # 6 igg2 ) is shown in table 22 . the results using the mda - mb - 453 xenograft model demonstrate that sh24c05 - 31 n62s - igg1 showed potent tumor growth inhibition by day 71 at all doses tested ( i . e ., 5 mg / kg , 10 mg / kg , and 20 mg / kg of body weight ). the results also demonstrate that at the 10 mg / kg dose , sh24c05 - 31 n62s - igg1 showed greater tumor growth inhibition by day 71 ( 84 %, p & lt ; 0 . 001 ) when compared to ab # 6 igg2 ( 62 %, p & lt ; 0 . 001 ). sh24c05 - 31 n62s - igg1 showed equivalent tumor growth inhibition as u1 - 59 at the same dose . the entire disclosure of each of the patent documents and scientific articles referred to herein is incorporated by reference for all purposes . the invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof . the foregoing embodiments are therefore to be considered in all respects illustrative rather than limiting on the invention described herein . scope of the invention is thus indicated by the appended claims rather than by the foregoing description , and all changes that come within the meaning and the range of equivalency of the claims are intended to be embraced therein .
monoclonal antibodies that bind and inhibit activation of epidermal growth factor receptor related member erbb3 / her3 are disclosed . the antibodies can be used to treat cell proliferative diseases and disorders , including certain forms of cancer , associated with activation of erbb3 / her3 .