Effects of isoprinosine and NPT 15392 on interleukin-2 (IL-2) production.

Two purine immunoenhancing drugs, isoprinosine and NPT 15392, were evaluated as inducers of IL-2 or enhancers of IL-2 induction by phytohemagglutinin (PHA). Both drugs were found to have significant enhancing activity on PHA induction of IL-2 by human lymphocytes over a wide range of concentrations. Alone they were unable to consistently induce IL-2 activity. NPT 15392 was able to enhance PHA-induced IL-2 production at 10-100 times lower concentrations than isoprinosine. The actions of these compounds to enhance IL-2 production may explain their effects on PHA-induced lymphocyte proliferation.