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T cells help to amplify inflammatory responses induced by Salmonella enterica serotype Typhimurium in the intestinal mucosa.

Godinez I, Haneda T, Raffatellu M, George MD, Paixão TA, Rolán HG, Santos RL, Dandekar S, Tsolis RM, Bäumler AJ

Department of Medical Microbiology and Immunology, School of Medicine, University of California at Davis, One Shields Ave., Davis, CA 95616-8645, USA.

Salmonella enterica serotype Typhimurium causes an acute inflammatory reaction in the ceca of streptomycin-pretreated mice. We determined global changes in gene expression elicited by serotype Typhimurium in the cecal mucosa. The gene expression profile was dominated by T-cell-derived cytokines and genes whose expression is known to be induced by these cytokines. Markedly increased mRNA levels of genes encoding gamma interferon (IFN-gamma), interleukin-22 (IL-22), and IL-17 were detected by quantitative real-time PCR. Furthermore, the mRNA levels of genes whose expression is induced by IFN-gamma, IL-22, or IL-17, including genes encoding macrophage inflammatory protein 2 (MIP-2), inducible nitric oxide synthase (Nos2), lipocalin-2 (Lcn2), MIP-1alpha, MIP-1beta, and keratinocyte-derived cytokine (KC), were also markedly increased. To assess the importance of T cells in orchestrating this proinflammatory gene expression profile, we depleted T cells by using a monoclonal antibody prior to investigating cecal inflammation caused by serotype Typhimurium in streptomycin-pretreated mice. Depletion of CD3+ T cells resulted in a dramatic reduction in gross pathology, a significantly reduced recruitment of neutrophils, and a marked reduction in mRNA levels of Ifn-gamma, Il-22, Il-17, Nos2, Lcn2, and Kc. Our results suggest that T cells play an important role in amplifying inflammatory responses induced by serotype Typhimurium in the cecal mucosa.

Published 21 April 2008 in Infect Immun, 76(5): 2008-17.
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