Isoprinosine potentiation of human peripheral blood mononuclear cell response to mitogens: kinetics and effect on expression of the IL-2 receptor and the activity of interleukin 2.

Isoprinosine, a synthetic purine derivative, enhanced the proliferative response of peripheral blood mononuclear cells to the lectin phytohaemagglutinin, and to the monoclonal antibody OKT3. The drug did not potentiate the activation of cells following oxidation by sodium periodate. Isoprinosine had no effect on the expression of receptors for interleukin-2. Increased interleukin-2 activity was detected in three out of nine supernatants from PHA activated mononuclear cells which were cultured in the presence of isoprinosine. Kinetic experiments involving addition or removal of the drug at various time intervals indicated that potentiation of the proliferative response required the presence of the drug at both early and late stages of cell activation. Inhibition of mononuclear cell activation by cyclosporine A was not affected by isoprinosine. These results suggest that enhancement of mononuclear cell proliferation by isoprinosine involves events in both early and late stages of the activation cycle.