Production, assay and partial characterization of guinea pig interleukin 2

Optimum conditions for the production and assay of guinea pig interleukin-2 (IL-2) have been established. The mitogenic activities of serial dilutions of guinea pig IL-2 preparations were compared in cultures of guinea pig peripheral blood lymphocytes prestimulated for 7 days with phytohemagglutinin (PHA) used at 1 microgram/ml. Parallel log dose-log response curves were used for quantitative comparisons. Optimum IL-2 yields were obtained from cultures of lymph node lymphocytes stimulated for 20 h with Concanavalin A (ConA) at 5 micrograms/ml. Guinea pig T cell lines reactive to mycobacterial antigens were propagated for several months using our IL-2 preparations. The molecular weight of guinea pig IL-2 was estimated to be 30,000 using S-200 gel filtration. The species specificities of guinea pig, human, mouse and rat IL-2s were examined. It was shown that guinea pig T lymphocyte blasts were stimulated only weakly with human IL-2 and not at all with mouse and rat IL-2.