Regulation of Human Interleukin‐2 and Interferon‐Gamma Gene Expression by Suppressor T Lymphocytes

Concomitant with induction of inlerleukin‐2 (IL‐2) and interferon‐gamma (IFN‐γ) gene expression in human tonsil cells, milogenic stimulation induces a transient activation of cells able to effectively suppress expression of these genes. Induction of IL‐2 and IFN‐y genes largely precedes appearance of suppressor cell activity, allowing expression of both genes to occur before strong down‐regulation is exerted by activated suppressor cells. Suppressive activity induced in one cell population can inhibit IL‐2 and IFN‐γ gene expression in another population from the same donor. The distinct nature of suppressor cells is supported by the absence of down‐regulation of IL‐2 gene expression in a helper cell line. M LA‐144: yet, in these cells, negative control can be expressed when active suppressor cells are introduced. Our findings support the concept that actual levels of IL‐2 and IFN‐γ gene activity are regulated to a large extent by the differential kinetics of activation of suppressor cells on one hand and of cells expressing the IL‐2 and IFN‐γ genes on the other.