Qualitative differences in effects of recombinant alpha-, beta- and gamma-interferons on human peripheral blood leukocytes in vitro.

: The in vitro effects of bacteria-produced human interferons alpha 2, beta and gamma on several properties of peripheral blood leukocytes from different healthy donors were compared. Treatment with HuIFN-alpha 2 or HuIFN-beta resulted in inhibition of the proliferative response to phytohaemagglutinin and in closely parallel induction of 2'-5'-oligoadenylate synthetase activity. In contrast, HuIFN-gamma had no significant effect on these two activities. However, all three HuIFN were able to enhance natural killer cell cytotoxicity and the expression of HLA-DR surface antigens, with only quantitative variations from donor to donor. Similar results were observed with glycosylated recombinant hamster-cell-derived HuIFN-gamma and with natural HuIFN-gamma. These data demonstrate qualitative differences in the effects of HuIFN-gamma compared to those of HuIFN-alpha 2 or -beta on cells of the immune system.