This project is designed to determine the mechanism(s) by which mycoplasmas and mycoplasma viruses induce interferon in cultured lymphocytes in vitro. Specifically we shall determine the nature of the mycoplasma and virus association with the lymphocyte, the cellular component responsible and the responding lymphocyte subpopulation. The relationship between interferon induction and mycoplasma-mediated induction of lymphocyte transformation and of lymphocyte cytotoxicity for fibroblast target cells will also be determined. The significance of interferon induction on the expression of mycoplasma-induced disease will also be evaluated.