Presence ofLpsdMutation Influences Cytokine Regulation In Vivo by theMycoplasma arthritidisMitogen Superantigen and Lethal Toxicity in Mice Infected withM. arthritidis

Open Access
Publisher Website
Google Scholar
Abstract
TheMycoplasma arthritidismitogen (MAM) superantigen (SAg) is a potent activator of human and murine cells and is produced by an organism that is a cause of acute and chronic arthritis of rodents. It is phylogenetically unrelated to other bacterial SAgs and exhibits a number of unique features. We recently demonstrated that MAM differentially regulates the cytokine responses of different mouse strains following in vivo administration. Here we show that the presence in inbred C3H/HeJ mice of the mutantLpsdgene, which is associated with a defect in Toll-like receptor 4 (TLR4), influences MAM regulation of cytokine profiles in vivo.Whereas the levels of type 1 cytokines (interleukin-2 [IL-2], gamma interferon, IL-12, and tumor necrosis factor alpha) were depressed in cells from MAM-injected wild-type C3H/HeSnJ mice, they were elevated in cells from C3H/HeJ mice. Furthermore, the levels of type 2 cytokines (IL-4, IL-6, and IL-10) were elevated inLpsnC3H/HeSnJ mice but depressed inLpsdC3H/HeJ mice. The transcript for IL-12 p40 was highly expressed in C3H/HeJ but not C3H/HeSnJ mice. F1mice exhibited the same cytokine profile as C3H/HeJ mice, indicating that the mutant gene exhibited dominant-negative inheritance. In addition, C3H/HeJ mice were highly susceptible to toxic death in comparison with C3H/HeSnJ mice after injection with liveM. arthritidisorganisms. Our results suggest that MAM interacts with the lipopolysaccharide signaling pathway, possibly involving TLR4 or a combinatorial Toll complex.