human liver tissue was taken from patients undergoing liver surgery for liver diseases , who had hbv viremia of 10 7 - 10 9 parciles / ml with positive hbv dna in the liver tissue . the liver tissue was implanted under the kidney capsule of the chimeric animals . although hbsag was easily detected in pre - infected hbv dna positive / hbeag positive transplanted tissue ( fig1 ), 1 - 3 months after liver fragment implantation hbv sequences were undetectable by pcr ( applyin primers spanning the viral core gene as well as the envelope region , at the a determinant of the hbsag ) in any of these experiments . furthermore , intravenous or intraperitoneal ( i . p .) injection of 200 μl of high - titer hbv particles (& gt ; 10 8 / ml ) following the transplantation of a normal human liver fragment , failed to generate hbv dna sequences during the next 30 days ( data not shown ). lymphocytes , positive for hbv dna by dot blot hybridization , were separated by lymphopheresis ( baxter fenwell cs - 3000 pulse blood cell separators , deerfield , ill ., u . s . a .) from a patient with hbv - related chronic liver disease whose sera were positive for hbv dna and hbeag . forty million hbv dna - positive lymphocytes were injected i . p . to each mouse , subsequent to transplantation of normal human liver at the subcapsular site of the kidney . hbv sequences were not detected in the sera of these animals during the following 21 days . although the primary infection site for hbv is hepatocytes , lymphocytes and endothelial cells have both been shown to harbor hbv transcripts and viral - related proteins [ j . romet - lemonne , et al ., science , vol . 221 , pp . 667 - 669 ( 1983 ); h . blum , et al ., proc . natl . acad . sci . u . s . a ., vol . 80 , pp . 6685 - 6688 ( 1983 ); e . galun , et al ., american journal of pathology , vol . 145 , pp . 1001 - 1007 ( 1994 )], suggesting a common specific cell membrane receptor mechanism supporting viral penetration . this mechanism would prevent infection of receptor negative cells , despite their being permissive for hbv replication by transfection [ e . galun , et al ., journal of general virology , vol . 73 , pp . 173 - 178 ( 1992 )]. all three primary cell types hosting hbv naturally , i . e ., hepatocytes , lymphocytes and endothelial cells , respond to hil6 through the human il6 receptor ( hil6r ) which is expressed on their cell membranes [ a . mackiewicz , et al ., the journal of immunology , vol . 149 , pp . 2021 - 2027 ( 1992 ); j . bauer , et al ., febs letter , vol . 249 , pp . 27 - 30 ( 1989 ); t . kishimoto , et al ., science , vol . 258 , p . 593 ( 1992 )]. furthermore , as previously shown , hil6 binds to hbv through ps1 . a fragment of normal human liver from a patient with no indication of any hbv - related markers or disease , was incubated ex - vivo with a high titer hbv dna - positive serum prior to transplantation under the kidney capsule of the chimeric animals . hbv dna sequences were undetectable by pcr from two different genomic regions in any of these animals during the month following transplantation . results are shown in fig2 a . these results were reproduced in additional experiments in over 50 mice , using four different hbv dna - positive sera . however , when liver tissue originating from the same patients was incubated ex - vivo with the above - mentioned hbv dna - positive sera togethcr with hil6 , hbv dna sequences were detected from day 16 to day 31 , in sera of about 50 % of the transplanted animals . these results are shown in fig2 b . similar results were obtained in experiments conducted under the above - stated conditions , using additional hbv dna sera and liver tissue from different sources . in these experiments , hbv dna sequences could be detected up to day 60 following transplantation ( results not shown ). pre - exposure of liver tissue to hil6 prior to incubation with hbv ex - vivo , increased infection to about 90 % of the animals . animals positive for hbv sequences in serum at day 31 were also positive for hbsag in the implanted hepatocytes , as shown in fig2 d . liver fragments incubated ex - vivo with hbv under the above conditions and fixed for immunohistochemical analysis prior to transplantation were negative for hbsag ( results not shown ). to further assess the role of hil6 in supporting hbv infection , a human hepatoblastoma cell line hepg2 ( atcc hb 8065 ), an hepg2 - derived , stably transfected hil6r cell line , a null hil6r ( a cell line which does not express hil6r ) named hepg2 - pdi and an hil6 producing line named hepg2 - hil6 [ s . rose - john , et al ., the journal of biological chemistry , vol . 268 , pp . 22084 - 22091 ( 1993 )] were incubated with hbv dna - positive sera , with or without hil6 . following incubation , the various mixtures were injected intrasplenically to the chimeric mice to generate hcc foci in the liver , as shown in fig3 . the results of these experiments are summarized below in table 1 . all cell lines grew in t25 flasks supplemented with dmem medium , enriched with 10 % fetal bovine serum . for infection experiments , cells were trypsinized and washed twice with pbs , followed by incubation with hbv - positive human sera ( 10 8 virions / ml ) in the presence or absence of hll6 ( 500 ng / ml ) in 1 - 2 ml of dmem . after 2 - 4 h incubation at 37 ° c ., 4 × 10 6 cells / ml , 0 . 5 ml / mouse were injected intrasplenically to 8 - 10 scid & gt ; bnx mice in each group . animals were splenectomized following the injection . mice were bled at two weekly intervals for 3 months , and dna was extracted from 100 μl sera . the dna was subjected to pcr amplification . the dna extraction and the pcr method applied are described in the legend of fig2 . table 1 summarizes three experiments . in mice implanted with hepg2 - hil6r cells ( which have about one log higher expression of the receptor than hepg2 cells ) subsequent to incubation with hbv in the presence of hil6 , hbv - dna sequences could be detected in serum 13 days after transplantation , whereas hbv sequences were not detected in the sera of mice who underwent the same procedure without the presence of hil6 . similar results were obtained in experiments using hepg2 - pdi cells . these cells do not express the gp 80 binding protein subunit of the hil6r on the cell membrane [ s . rose - john , et al ., ibid . ; m . ehlers , et al ., the journal of immunology , vol . 153 , p . 1744 ( 1994 )], however , they do express the signal transduction gp 130 subunit of the receptor , which is essential for efficient intemaliztion of hil6 [ e . dittrich , et al ., the journal of biological chemistry , vol . 269 , pp . 10914 - 19020 ( 1994 )]. in experiments of the same design , using hepg2 cells in the presence and also in the absence of hil6 , hbv sequences could be detected in a number of murine sera . these results are similar to those previously reported by petit , et al . [ r . bchini , et al ., ibid . ], showing a low reproducibility in which only three sera supported hbv infection of hepg2 cells in - vitro , out of a total of 55 different serum samples taken from hbv dna - positive patients . the hepg2 - hil6 cell line , which produces hil6 , generated hbv sequences in mice sera following incubation with the virus , with or without external supplementation of hil6 . when the liver fragment was incubated ex - vivo with hbv - dna positive sera in the presence of commercially available human polyclonal anti - hbs viral neutralizing antibodies ( hbig , hepatect ®, biotest pharma gmbh , dreicich . germany ), hbv - dna was observed at day 11 following transplantation only in 48 % ( 10 / 21 ) of mice , as compared to 78 % ( 14 / 18 ) of the untreated mice group ( table 2 ). for antibody treatment , hbv - dna positive serum ( 0 . 5 ml ) was incubated with 100 iu of hbig for 2 hours at 25 ° c . human liver fragments were then added to the untreated or hbig treated hbv - dna positive serum according to the same protocol as described above , followed by implantation under the kidney capsule of the chimeric animal . mice sera were analyzed for the presence of hbv - dna sequences 11 days after transplantation . referring again to the figures , fig1 shows pre - infected liver fragment from a hbv dna - positive patient , one month after sub - capsular implantation in a scid & gt ; bnx chimeric mouse , stained for hbsag . from fig2 it can be seen that hil6 mediates hbv viremia in scid & gt ; bnx chimeric mice transplanted with human tissue . pcr amplification products of hbv pre - core / core region following dna extraction from sera of mice , 16 and 31 days after sub - capsular kidney transplantation of normal human liver fragments . the human liver fragments were incubated ex - vivo prior to transplantation with human hbv positive serum ( fig2 a ); hbv serum and hil6 simultaneously ( fig2 b ), or preincubated with hil6 and later with hbv sera fig2 c ). in each of fig2 a to 2 c , the upper panel is an etbr staining and the lower panel is an 32 p hbv linear insert hybridization result of the same gel . the molecular marker size ( m ) is indicated by an arrow ; numbers at the head of each panel indicate mice identification numbers ; + for positive serum control and − for negative serum control . fig2 d shows hbsag staining of an ex - vivo hbv incubation of a normal liver fragment with hil6 . one month following implantation under the kidney capsule of scid & gt ; bnx mice . sera from hbv - positive patients , containing approximately 10 8 virions / ml , were used for infection . small fragments of normal human liver were incubated with 400 μl sera in 1 ml dmem supplemented with 2 μg / ml polybrene in the absence ( group a ) or presence ( group b ) of hil6 ( 500 ng / ml ) incubated for 2 - 4 h at 37 ° c . in group c , the liver fragments were treated with hil6 for 2 h at 37 ° c . before the addition of hbv - positive sera and polybrene . after incubation , 4 - 5 ml polybrene dmem were added and the liver fragments were transplanted under the kidney capsule to groups a , b and c of scid & gt ; bnx chimeric mice ( 10 , 19 and 11 mice , respectively ). at 2 weekly intervals for 4 months , blood was collected retrobulbarily from each mouse . 100 μl of serum samples were treated with 0 . 5 mg / ml proteinase k in 10 mm edta and 0 . 25 % sds for 2 h at 55 ° c . or overnight at 37 ° c ., extracted twice with phenol , once with phenol - chcl 3 , and once with chcl 3 . dna was precipitated with ethanol , using 0 . 5m nacl and a dna microcarrier . dna was dissolved in 30 μl tris - edta , ph 8 . 0 , and was subjected to pcr amplification . the 50 μl pcr reaction volume contained 10 ρmole of each oligonucleotide primer in reaction buffer ( 10 mm tris - hcl , ph 8 . 3 , 50 mm kcl , 2 . 0 mm mgcl 2 , 0 . 01 % ( w / v ) gelatin , 250 μm of datp , dgtp , dctp , dttp and 0 . 5 u of taq polymerase . the reaction mixtures were overlaid with 30 μl of mineral oil . pcr cycles included 94 ° c . for 1 min ., 55 ° c . for 1 min . and 72 ° c . for 3 min ., 35 repeated cycles . 10 μl of reaction mixture was analyzed on a 2 % agarose gel . oligonucleotides used for the pre - core / core amplification were : sequence originated from adw subtype ; nt numbering starts from ecori site . the expected size of the pcr dna product is 668 - bp . the pcr samples were electrophoresed on 2 % agarose gel and transferred to a nylon membrane ( biodynea ), hybridized with a nick - translated probe . the autoradiogram was exposed with intensifying screens at − 70 ° c . for 7 h . in order to confirm the pcr results , the mice serum samples were also subjected to pcr amplification with primers spanning the envelope gene region , showing the same results ( data not shown ). reproducible results were obtained from four similar experiments while there were 10 - 20 mice in each group . based on the present discovery that hil6 acts to mediate hbv infection , it is possible to prepare an antiviral / anti - hbv agent . a pharmaceutical composition for the prevention of hbv infection , comprising an active ingredient having an amino acid sequence similar to hil6 , is thus developed . the hil6 domain which interacts with hil6rα ( r for receptor ) and / or hil6rβ ( amino acid residues : 40 - 60 , 70 - 100 and 135 - 175 ) antagonizes hil6 interaction to prevent hbv infection . set forth at fig4 is the nucleotide sequence for human interleukin 6 mrna ( seq id no 1 ), as published by l . t . may , et al ., “ anti - beta interferon antibodies inhibit the increased expression of hla - b7 mrna in tunor necrosis factor - treated human fibroblasts : structural studies of the beta - 2 interferon involved ,” proc . nat &# 39 ; l acad . sci . u . s . a . 83 ( 23 ), 8957 - 8960 ( 1986 ). fig5 a and 5 b depict the nucleotide sequence for the human interleukin 6 receptor mrna ( seq id no 2 ), as published by k . yamasuki , et al ., “ cloning and expression of the human interleukin 6 ( bsf - 2 / isn beta 2 ) receptor ,” science 241 ( 4867 ), 825 - 828 ( 1988 ). fig6 depicts the nucleotide sequence for the interleukin - 6 receptor ( seq id no 3 ), as published by h . schooltink , et al ., “ structural and functional studies on the human nepatic interleukin - 6 receptor ,” biochem . j . 277 : 659 - 664 ( 1991 ). fig7 a and 7 b depict the nucleotide sequence for the gp 130 interleukin 6 receptor ( seq id no 4 ), as published by m . hibi , et al , “ molecular cloning and expression of an il - 6 signal transducer , gp 130 ,” cell 63 ( 6 ), 1149 - 1157 ( 1990 ). fig8 depicts the amino acid sequence for the human interleukin 6 receptor alpha ( il - 6r alpha ) ( seq id no 5 ), as published by k . yamasaki , et al ., “ cloning and expression of the human interleukin 6 ( bsf - 2 / isn beta 2 ) receptor ,” science 241 ( 4867 ), 825 - 828 ( 1988 ). fig9 depicts the amino acid sequence for human interleukin 6 ( seq id no . 6 ), as published by c . nishimura , et al ., biochemistry 35 : 273 - 281 ( 1996 ). the molecular analysis of hil6 binding sites with gp130 and gp80 revealed a number of structural targets on hil6 which can serve as hil6 antagonists . the preferable target for an hil6 antagonist is to disrupt the hil6 / hil6rα complex with hil6rβ . based on previous publication , a number of domains essential for hil6 activity were reported : 1 . lys41 - ala56 ( site 2a , also named β2 ) is involved in the activation of signal - transduction . 2 . gly77 - glu95 ( site 2c ) is important for interaction with hil6rα , subunit gp80 . 3 gln153 - his165 ( site β1 ), substitution of trp158 to arg or gln160 to glu combined with thr163 to pro - antagonize the biological activity of hil6 . 4 . a combined β1 and β2 hil6 mutant ( mhil6β1 + β2 ) is inactive on xg - 1 hil6 responsive cells , with a weakly antagonizing activity . 5 . the addition of two substitutions to the mhil6 ( m for mutant ) β1 + β2 , phe171 to leu and ser177 to arg , resulted in an increase in the affinity to hil6rα , while inhibiting its activity on xg - 1 cells . based on techniques known per se to persons skilled in the art , the proteins and peptides for use in the pharmaceutical compositions of the present invention are readily prepared , e . g ., by the following techniques and steps : amplification of chosen segment of dna from plasmid containing hbv dna ( adw2 )- adw htd by pcr , using primers constructed so as to introduce bamh1 and ecor1 sites compatible to the pgex - 2t ( pharmacia , uppsala , sweden , catalogue no . 27 - 4801 - 01 ) insertion site . this gst fusion vector provides a system in which fusion proteins are easily purified from the bacterial lysates and can be detected directly as a fusion protein or after cleavage with site specific proteases . after introduction of dna into pgex - 2t , competent e . coli ( jm109 ) are transformed and cloned ( lb + 10 μg / ml ampicillin ). protein expression is induced by the addition of iptg ( 0 . 1 mm , isopropyl - 1 - thio - b - d - galactoside ) for 1 - 2 hours . fusion protein is removed from lysed ( sonicated ) cells by collection on glutathione - agarose beads ( pharmacia ) and eluted from beads using reduced glutathione ( 5 mm in 50 mm tris - cl , ph 8 . 0 ). identification and determination of protein can be done either by use of antibodies to gst or by specific recognition of inserted protein . the complete hbv ps1 protein ( aa 1 to aa 119 , applying pcr with the sense and anti - sense primers 5 ′- cgggatccatgggaggttggtcatc - 3 ′[ nt 8 + 2856 - 2873 , ecor1 as starting site for nt numbering ] ( sequence id no . 9 ) and 5 ′- ggaattccactgcatggc - 3 ′ [ nt 6 - 3210 ] respectively ) ( sequence id no . 10 ) and the ps1 attachment site aa21 to aa46 constructs were designed and produced in the pgex - 2t system ( compound b in fig1 ). truncated soluble forms of gp80 and gp130 are synthesized using the pgex - 2t system as described for the preparation of ps1 ( compound a2 and a1 , respectively ). hil6 derived peptides ( lys41 - ala56 , gly77 - glu95 and gln153 - his165 , designated c1 , c3 and c2 , respectively , in fig1 ) are synthesized by applying a variety of methods including merrifield solid - phase synthesis and derived methods or other acceptable genetic engineered methods . the compounds produced are linear or cyclic peptides , or parts of large proteins . compositions according to the present invention can be administered orally or parenterally , including intravenous , intraperitoneal , intranasal and subcutaneous administration . implants of the compounds are also useful . the proteins of the present invention are administered in combination with other drugs , or singly , consistent with good medical practice . the composition is administered and dosed in accordance with good medical practice , taking into account the clinical condition of the individual patient , the site and method of administration , scheduling of administration , and other factors known to medical practitioners . the ‘ effective amount ’ for purposes herein is thus determined by such considerations as are known in the art . when administering the compositions parenterally , the pharmaceutical formulations suitable for injection include sterile aqueous solutions or dispersions and sterile powders for reconstitution into sterile injectable solutions or dispersions . the carrier can be a solvent or dispersing medium containing , for example , water , ethanol , polyol ( for example , glycerol , propylene glycol , liquid polyethylene glycol , and the like ), suitable mixtures thereof , and vegetable oils . proper fluidity can be maintained , for example , by the use of a coating such as lecithin by the maintenance of the required particle size in the case of dispersion , and by the use of surfactants . non - aqueous vehicles such as cottonseed oil , sesame oil , olive oil , soybean oil , corn oil , sunflower oil , or peanut oil and esters such as isopropyl myristate , may also be used as solvent systems for compound compositions . additionally , various additives which enhance the stability , sterility , and isotonicity of the compositions , including antimicrobial preservatives , anti - oxidants , chelating agents , and buffers , can be added . prevention of the action of microorganisms can be ensured by various antibacterial and antifungal agents , for example , parabens , chlorobutanol , phenol , sorbic acid , and the like . in many cases , it will be desirable to include isotonic agents , for example sugars , sodium chloride , and the like . prolonged absorption of the injectable pharmaceutical form can be brought about by the use of agents delaying absorption , for example , aluminum monostearate and gelatin . according to the present invention , however , any vehicle , diluent or additive used would have to be compatible with the compounds . sterile injectable solutions can be prepared by incorporating the proteins utilized in practicing the present invention in the required amount of the appropriate solvent with various of the other ingredients , as desired . a pharmacological formulation described and claimed herein can be administered to the patient in an injectable formulation containing any compatible carrier , such as various vehicle , adjuvants , additives , and diluents ; or the compounds utilized in the present invention can be administered parenterally to the patient in the form of slow - release subcutaneous implants or targeted delivery systems , such as polymer matrices , liposomes , and microspheres . an implant suitable for use in the present invention can take the form of a pellet which slowly dissolves after being implanted , or a biocompatible delivery module well - known to those skilled in the art . such well - known dosage forms and modules are designed such that the active ingredients are slowly released over a period of several days to several weeks . examples of well - known implants and modules useful in the present invention include : u . s . pat . no . 4 , 487 , 603 , which discloses an implantable micro - infusion pump for dispensing medication at a controlled rate ; u . s . pat . no . 4 , 486 , 194 . which discloses a therapeutic device for administering medicants through the skin ; u . s . pat . no . 4 , 447 , 233 , which discloses a medication infusion pump for delivering medication at a precise infusion rate ; u . s . pat . no . 4 , 447 , 224 , which discloses a variable flow , implantable infusion apparatus for continuous drug delivery ; u . s . pat . no . 4 , 439 , 196 , which discloses an osmotic drug delivery system having multi - chamber compartments ; and u . s . pat . no . 4 , 475 , 196 , which discloses an osmotic drug delivery system . these patents are incorporated herein by reference . many other such implants , delivery systems and modules are well - known to those skilled in the art . a pharmacological formulation of the present invention can be administered orally to the patient . conventional methods such as administering the compounds in tablets , suspensions , solutions , emulsions , capsules , powders , syrups and the like , are usable . known techniques which deliver the new compositions orally or intravenously and retain the biological activity , are preferred . in one embodiment , the new compositions can be administered initially by intravenous injection . the quantity of the compositions to be administered will vary for the patient being treated , and will vary from about 100 ng / kg of body weight to 100 mg / kg of body weight per day , and preferably will be from 10 μg / kg to 10 mg / kg per day . it will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative examples and that the present invention may be embodied in other specific forms without departing from the essential attributes thereof , and it is therefore desired that the present embodiments and examples be considered in all respects as illustrative and not restrictive , reference being made to the appended claims , rather than to the foregoing description , and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein .
the invention provides a pharmaceutical composition for the treatment of hepatitis b virus infection , comprising an amount of a soluble active agent which interacts with at least one of the binding sites between hil6 and ps1 and between hil6 and hepatocytes and other hbv - permissive cells , the active agent being present in sufficient amount to competitively bind to at least one of the sites and thereby to prevent hil6 - mediated hbv infection of hepatocytes and other hbv - permissive cells .