Stimulation of normal lymphocytes with autologous lymphoid cell lines: properties of derived killer cells.

Lymphocytes from normal adults, with or without serological signs of previous Epstein-Barr virus (EBV) infection, could be stimulated to proliferate and produce killer cells by incubation with autologous EBV-genome-positive lymphoid cell lines (LCLs). The stimulated cells were most probably of T-cell origin, although at the peak of stimulation many of them lacked the sheep erythrocyte marker. Direct effector-target cell contact was necessary for lysis to occur. The cytotoxicity of autologously stimulated (AS) lymphocytes was not restricted to EBV-genome-positive LCLs, nor to cell lines of hematopoietic origin. It was equally broad if cells carrying complement receptor had been removed before stimulation. Fresh lymphocytes, blasts induced by phytohemagglutinin or concanavalin A, and Burkitt's lymphoma biopsy cells were resistant or considerably less sensitive. Mouse cells--even cell lines--were resistant. The sensitivity of target cells to lysis correlated positively with their capacity to block AS lymphocyte lysis of autologous LCLs in competition experiments. The cytotoxicity of AS lymphocytes was blocked by EBV-genome-positive and -negative cell lines, whereas the EBV-related cytotoxicity of T cells from acute cases of infectious mononucleosis was blocked by EBV-genome-positive LCL only.