SALMONELLA INFECTION-INDUCED NONRESPONSIVENESS OF MURINE SPLENIC T-LYMPHOCYTES TO INTERLEUKIN-2 (IL-2) INVOLVES INHIBITION OF IL-2 RECEPTOR-GAMMA CHAIN EXPRESSION

In a previous study we demonstrated that Salmonella typhimurium-induce d immunosuppression involved T-cell nonresponsiveness to interleukin-2 (IL-2). In this study we observed that Salmonella-induced T-cell non- responsiveness to IL-2 was nut reversed completely by treatment with N -G-monomethyl-L-arginine, which is known to inhibit nitric oxide (NO) secretion by macrophages in culture. Furthermore, when purified spleni c T-lymphocytes from Salmonella-infected mice were activated with an a nti-CD3 antibody, the responsiveness of these T-cells to IL-2 was supp ressed significantly. Results of flow cytometric analysis using an ant i-IL-2 receptor gamma chain (IL-2R gamma) antibody showed that IL-2R g amma expression in mitogen-activated T-cells was down-regulated by Sal monella infection. These results suggest that Salmonella infection-ind uced T-cell non-responsiveness to IL-2 involves a defective function o f T-cells themselves and appears to be regulated by inhibition of IL-2 R gamma expression in T-cells. (C) 1998 Federation of European Microbi ological Societies. Published by Elsevier Science B.V.