Suppression of Staphylococcus aureus Superantigen-Independent Interferon Gamma Response by a Probiotic Polysaccharide. Journal Article

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Authors: Paik, W; Alonzo, F; Knight, KL
Article Title: Suppression of Staphylococcus aureus Superantigen-Independent Interferon Gamma Response by a Probiotic Polysaccharide.
Abstract: is a Gram-positive opportunistic pathogen that causes a variety of diseases. Bloodstream infection is the most severe, with mortality rates reaching 20 to 50%. Exopolysaccharide (EPS) from the probiotic reduces bacterial burden and inflammation during bloodstream infection in mice. Protection is due, in part, to hybrid macrophages that restrict growth through reactive oxygen species and to limiting superantigen-induced T cell activation and interferon gamma (IFN-?) production during infection. A decrease in IFN-? production was observed within 24?h after infection, and here, we investigated how EPS abrogates its production. We discovered that uses a rapid, superantigen-independent mechanism to induce host IFN-? and that this is mediated by interleukin-12 (IL-12) activation of NK cells. Furthermore, we found that EPS limits IFN-? production by modulating host immunity in a Toll-like receptor 4 (TLR4)-dependent manner, a signaling pathway that is required for EPS-mediated protection from infection We conclude that EPS protects hosts from acute bloodstream infection not only by inducing macrophages that restrict growth and inhibit superantigen-activated T cells but also by limiting NK cell production of IFN-? after infection in a TLR4-dependent manner.
Journal Title: Infection and immunity
ISSN: 1098-5522; 0019-9567
Publisher: American Society for Microbiology. All Rights Reserved  
Date Published: 2020