Inhibition of T-cell proliferation induced by a cell-free Salmonella typhimurium extract does not involve a nitric oxide-mediated mechanism.
In a previous study, we observed that a cell-free Salmonella typhimurium extract induced suppression of mitogen-induced T-cell proliferation and that this suppression involved nonresponsiveness of T-cells to interleukin-2 (IL-2) and augmentation of IL-2 receptor (IL-2R) expression. In this study, we found that inhibition of phytohemagglutinin (PHA)-stimulated murine spleen cell proliferation induced by a cell-free S. typhimurium extract was reversed by treatment with an anti-interferon-gamma monoclonal antibody (anti-IFN-gamma Ab), but not by interleukin-4 or NG-monomethyl-L-arginine, which is known to inhibit nitric oxide (NO)-secretion from spleen cells in culture. However, IL-2R expression was augmented by treatment with the extract, although this was independent of an NO-mediated mechanism. Only anti-IFN-gamma Ab treatment reduced the augmented IL-2R expression to a normal level. These results suggest that the suppression of T-cell proliferation induced by the Salmonella cell-free extract is associated with augmentation of IL-2R expression in an NO production-independent manner.
Matsui
K
K
Department of Microbiology, Meiji College of Pharmacy, Tokyo, Japan.
Arai
T
T
D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives* / Q000494:pharmacology; D002474:Cell-Free System; D002478:Cells, Cultured; D008213:Lymphocyte Activation; D051379:Mice; D008807:Mice, Inbred BALB C; D009569:Nitric Oxide / Q000378:metabolism*; D015375:Receptors, Interleukin-2; D012486:Salmonella typhimurium / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*; D019323:omega-N-Methylarginine
D015375:Receptors, Interleukin-2; D019323:omega-N-Methylarginine; D009569:Nitric Oxide; D001120:Arginine