Comparison of multiple assays for detecting human antibodies directed against surface antigens on normal and malignant human tissue culture cells.

Four separate assays of human antibody reactivity to four separate normal and malignant human tissue culture cell lines from two patients have been evaluated using a single highly-reactive allogeneic serum. The visual and end-point cytolysis assay and the 51Chromium release assay were equally sensitive in measuring complement mediated antibody cytoxicity and both were far more sensitive than a trypan blue dye exclusion assay. The assay of antibody reactivity by hemadsorption technique was about 10 times more sensitive than any of the cytotoxicity assays. This latter assay measures only IgG antibody however. These assays showed that cell lines from different patients may differ greatly in 'reactivity' to an allogeneic serum and emphasized the importance of utilizing tumor and normal cells from the same patient when using tissue culture cells to search for tumor specific reactivity. These observations emphasize the importance of utilizing multiple assays against paired normal and malignant cells from the same patient to be certain of the specificity and magnitude of the measured antibody.