Cloned human T-cell lines with allospecific or natural killer-like cytotoxicity

Cloned human T-cell lines were produced by limiting dilution of lymphocytes alloactivated in mixed leukocyte cultures, followed by expansion of clonal progeny with interleukin 2. Selected clones were analyzed for cell-mediated cytotoxicity (CTX) against a variety of targets susceptible or resistant to lytic attack by natural killer (NK) cells. Clones with classical alloantigen-restricted lytic capacity for normal lymphoid targets were found to be distinct from those mediating natural killer-like CTX against NK-susceptible cell line targets. This was established by direct CTX assays and by cold target cross-competition experiments. Moreover, clones with NK-like activity displayed heterogeneous patterns of lysis on different target cell lines in direct CTX, suggesting a clonal distribution of receptors for NK-like target antigens amongst these cultured human NK-active T-cell clones.