PRODUCTION AND CHARACTERIZATION OF THE MURINE MONOCLONAL ANTIBODY-2G10 TO A HUMAN T4-TYROSINASE EPITOPE

Employing as immunogen a short-term passaged, highly pigmented human melanoma cell line, we have produced the murine MoAb 2G10 of the IgG1 isotype. The antibody immunoprecipitated from S-35-methionine and H-3-glucosamine metabolically labeled human melanoma cells with a single-chain glycoprotein of 75 kD molecular weight. No such molecule could be precipitated from murine melanomas. To further investigate the fine specificity of the MoAb, immuno-chemical and immunohistochemical studies were performed. These studies demonstrated that MoAb 2G10 binds a significant fraction of tyrosinase activity from cell lysates, completely immunodepletes soluble cell extract of T4-tyrosinase molecules, and produces immunostaining patterns superimposable on those obtained with anti-T4-tyrosinase antibodies. Thus, MoAb 2G10 appears to recognize a human-specific determinant carried by either T4-tyrosinase or a closely related molecule. The functional relevance of this epitope remains to be evaluated.