A solid-phase radioimmunoassay to detect antibodies produced by hybridomas to antigens derived from human melanoma cells.

A solid-phase radioimmunoassay to detect antibodies that react with antigens derived from human melanoma cells is described. A soluble preparation derived from Nonidet P-40 lysates of tissue-cultured melanoma cells was dried on the surfaces of wells of polyvinyl chloride microtiter plates and fixed with 0.02% glutaraldehyde. Antibody preparations were added and incubated for 18 h at 4 degrees C. The wells were washed and bound antibodies were detected using radioactive Staphyloccoccal protein A (125I-SpA). Optimal conditions are described for all the steps employed. Concentrations of antigen selected, the amount of 125I-SpA employed and the duration of incubation of antibodies with antigen were found to be critical. The assay was sensitive and reproducible, and lent itself to the simultaneous evaluation of many individual antibody samples in a short period of time. The assay was particularly valuable for rapid screening of hybridoma supernatants for antibodies to antigens derived from melanoma cells and from a panel of other tumor and normal cells.