Deoxyspergualin inhibits cytotoxic T lymphocytes but not NK or LAK cells

Deoxyspergualin (DOSP) is a new immunosuppressive agent which probably inhibits various functions of monocytes, B cells and T cells. We examined the effects of deoxyspergualin on cellular cytotoxicity, including cytotoxic T lymphocyte (CTL) mediated killer, natural killer (NK) cell and lymphokine activated killer (LAK) cell killing. Deoxyspergualin inhibited cellular cytotoxicity generated by 7 days allo‐antigenic challenge: it also inhibited cell killing if added on day 6 of this 7 day culture period. The drug did not significantly inhibit NK or LAK cell killing. The inhibitory effects of deoxyspergualin, however, were dependent on the serum used in the culture medium. Normal human serum (NHS) was associated with less inhibition than fetal calf serum (FCS). Finally, interleukin 2 (IL‐2) was able to prevent the inhibitory effects of deoxyspergualin on antigen‐specific cytotoxicity.