We established two human melanoma cell lines from a patient with melanoma. One of the cell lines (SMMU-1) was established from the lymph node of the metastatic tumor. The other cell line was established from the primary tumor (SMMU-2). Interestingly, SMMU-1 is metastatic in SCID mice when injected subcutaneously, while SMMU-2 is not. A subtractive immunization protocol was used to generate monoclonal antibodies (Mabs) reactive with the metastatic melanoma SMMU-1 but not with the nonmetastatic melanoma SMMU-2. We obtained 12 monoclonal antibodies specific for the metastatic melanoma SMMU-1. We will examine the expression of the antigens recognized by our Mabs on other human melanoma cell lines, normal human melanocytes and human melanocytes transformed with SV40 T antigen. In addition we will determine whether these antigens are expressed on normal human tissues and/or human tumors other than melanomas. These results should reveal whether some of these Mabs are indeed specific for metastatic human melanoma. We propose to biochemically characterize the antigens recognized by these Mabs. Preliminary experiments revealed that one of the Mabs we have generated can whether any of the other Mabs can interfere with the growth and/or metastasis of SMMU-1 in vivo. We will investigate whether any of the other Mabs can interfere with growth and/or metastasis of our human melanomas in SCID mice. It is hoped that some of our Mabs may recognize tumor specific transplantation antigens present on human melanomas. These antigens may be the targets for immunotherapeutic approaches in patients with malignant melanoma.