In vitro immunization of human B lymphocytes with cultured melanoma cells (SK-MEL 28).

Human peripheral blood lymphocytes (PBL) from 10 healthy donors were in vitro immunized using the human melanoma cell line SK-MEL 28 as an immunogen. The parameters necessary to obtain an optimal immune response against the tumor cells in vitro were determined. Different ratios of PBL and SK-MEL 28 were tested during the in vitro immunization period, and their effect on cell viability, specific antibody secretion, and yield of antigen-specific EBV clones was determined. A statistically significant positive dose-response relation was shown to exist between the immunogenic dose present during in vitro immunization and the number of antigen-specific EBV clones that was obtained. A ratio of PBL:SK-MEL 28 cells of 1:1 was found to be optimal and gave 2.6% positive clones from which human monoclonal antibodies specific for the melanoma cells were detected.