Generation in vitro of EBV-induced specific cytotoxic T cells in autologous serum avoids complications due to self-preferred foetal calf serum-specific T-cell cytotoxicity.

A previous report has established that in cultures of human mononuclear leukocytes, foetal calf serum (FCS) is capable of generating high levels of T cells preferentially cytotoxic for the autologous lymphoblastoid cell line (LCL). The present study compared the capacity of Epstein-Barr virus (EBV) to generate cytotoxic T cells in cultures of mononuclear cells grown in FCS in this system. Five EBV-seropositive and three seronegative donors were used and cultures were harvested at 14 days. With cultures from seropositive donors, whether grown in FCS or in autologous serum, EBV infection generated T cells cytotoxic for the autologous LCL; the response in uninfected control cultures was markedly lower. With seronegative donor cultures grown in FCS, there was virtually no difference in the capacity of T cells generated in infected or uninfected cultures to lyse the autologous LCL. Moreover, cells from seronegative donors cultured in human serum gave no detectable lysis of autologous LCL in either infected or uninfected cultures, clearly showing the absence of a response to EBV. This evidence shows that it is possible to distinguish the generation of specific cytotoxic T cells by FCS from generation by EBV, and with certain donors the apparently EBV-induced response may actually include a significant component induced by FCS in the medium. The cytotoxicity patterns of EBV-induced and FCS-induced T cells for autologous and allogeneic LCL targets showed a degree of parallelism, stressing the need for caution in interpretation of data obtained from cultures using FCS.