Search for specificity in natural cell-mediated cytotoxicity.

Differences in antigenicity between the human osteosarcoma cell line TE 85/B and its feline sarcoma virus-infected subline NIH E1041 were detected by competitive inhibition of natural cell-mediated cytotoxicity (NCMC). Whether the differences could be attributed to the viral infection was investigated by absorption and elution studies of antibodies that determine the specificity of NCMC against the cell lines. Antibodies from the serum of healthy individuals were first absorbed onto target cells against which they were to be tested and then eluted to provide antibodies putatively specific for the target cells. Trypsin-treated effector cells were restored with the absorbed serum or eluted antibodies and tested against TE 85/B and its intentionally infected sublines. The differences observed previously between TE 85/B and NIH E1041 were extended to the detection of small differences in antigenicity among all sublines. Separately maintained sublines from the same culture became antigenically different with continuous passage. The causes for these specific changes were unknown, but a role for the control of these antigens by NCMC was suggested. Differences in antigenicity between virus-infected sublines cultured separately need not be related to the virus infection.