Release of cytokines induced by Salmonella typhimurium porins

Abstract

Salmonella typhimurium SH5014 porins induce the release of tumor necrosis factor alpha (TNF-α), interleukin 1α (IL-1α), and IL-6 by human monocytes and of gamma interferon (IFN-γ) and IL-4 by human lymphocytes. Porins at 1 μg/ml induce the greatest release of TNF-α, IL-1α, and IL-6 by monocytes and of IL-4 by lymphocytes, while porins at 5 μg/ml induce the greatest release of IFN-γ by lymphocytes. The R form of lipopolysaccharide (LPS-R) induces the greatest release of TNF-α and IL-1α by monocytes when used at a low concentration (1 μg/ml). At higher concentrations (5 and 10 μg/ml, respectively), LPS-R induces the maximal release of IL-6 from monocytes and the maximal release of IL-4 from lymphocytes. The S form of LPS (LPS-S) induces the greatest release of TNF-α, IL-1α, and IL-6 by monocytes and that of IL-4 by lymphocytes when used at a concentration of 1 μg/ml. After stimulation with LPS-S, the largest quantity of TNF-α and IL-1α released was less than that obtained after stimulation with LPS-R at the same concentration, while the quantity of IL-6 released was found to be slightly higher than that obtained after stimulation with porins or LPS-R. LPS-S (1 μg/ml) induces IFN-γ release from lymphocytes in notably smaller quantities than that obtained with LPS-R and slightly larger quantities than that obtained with porins. The preparation of porins used was found to be contaminated with 10 pg of LPS per 10 μg of porins, a quantity which was found to have no biological effect; furthermore, porin preparations with the addition of polymyxin B gave the same results.