Specificities in natural cell-mediated cytotoxicity against lymphoblastoid cell lines. I. Selective inhibition by cross-competition.

The apparent nonselective effects of natural cell-mediated cytotoxicity tested directly on different lymphoblastoid cell targets were found to be quite specific in the cross-competition assay. The specificity was detected through inhibition of cytotoxicity by competitor cells sharing common specificities with the target cells. Cross-competition tests were performed employing eight lymphoblastoid lines including four T and four B cells. Selective inhibition observed between lymphoblastoid cell lines indicated that T and B cell lines were more antigenically similar within each group than between them. The target antigens that distinguish T cell from B cell lines have been tentatively called TA-T and TA-B.