Serological response of melanoma patients receiving melanoma cell vaccines. I. Autologous cultured melanoma cells.

Our past studies have defined Class 1 (unique), Class 2 (shared) and Class 3 (widely distributed) melanoma cell surface antigens by serological typing with autologous antibody. These definitions provide the basis for determining the immunogenicity of a series of melanoma vaccines in patients with malignant melanoma. The first vaccine we tested in this way was prepared from autologous melanoma cell lines, and the results of our trial are the basis of this report. Thirteen patients with metastatic malignant melanoma were vaccinated with irradiated, cultured autologous melanoma cells mixed with BCG in an attempt to induce a serological response to Class 1 or 2 melanoma antigens. Antibodies were measured by protein A (PA), mixed hemadsorption (MHA), immune adherence (IA), C3-mixed hemadsorption (C3-MHA) and antibody-dependent cell-mediated cytotoxicity (ADCC) assays. The specificity of observed reactions was defined by absorption analysis. Eight patients showed an increase in the titer of antibodies to autologous melanoma cell surface antigens after vaccination. In two of these patients, the antibodies had specificity for shared melanoma antigens. In six patients, the antibodies were directed solely against antigens related to the fetal calf serum (FCS) used in growing cells for serological testing and vaccine preparation. We conclude that unmodified autologous cultured melanoma cells, administered as they were in this trial, induce a serological response to melanoma cell surface antigens only in exceptional cases.