Trichinella spiralis Infection Suppressed Gut Inflammation with CD4⁺CD25⁺Foxp3⁺T Cell Recruitment

Abstract

In order to know the effect of pre-existing Trichinella spiralis infection on experimentally induced intestinal inflammation and immune responses, we induced colitis in T. spiralis-infected mice and observed the severity of colitis and the levels of Th1, Th2, and regulatory cytokines and recruitment of CD4+CD25+Foxp3+ T (regulatory T; Treg) cells. Female C57BL/6 mice were infected with 250 muscle larvae; after 4 weeks, induction of experimental colitis was performed using 3% dextran sulfate sodium (DSS). During the induction period, we observed severity of colitis, including weight loss and status of stool, and evaluated the disease activity index (DAI). A significantly low DAI and degree of weight loss were observed in infected mice, compared with uninfected mice. In addition, colon length in infected mice was not contracted, compared with uninfected mice. We also observed a significant increase in production of pro-inflammatory cytokines, IL-6 and IFN-γ, in spleen lymphocytes treated with DSS; however, such an increase was not observed in infected mice treated with DSS. Of particular interest, production of regulatory cytokines, IL-10 and transforming growth factor (TGF)-β, in spleen lymphocytes showed a significant increase in mice infected with T. spiralis. A similar result was observed in mesenteric lymph nodes (MLN). Subsets of the population of Treg cells in MLN and spleen showed significant increases in mice infected with T. spiralis. In conclusion, T. spiralis infection can inhibit the DSS-induced colitis in mice by enhancing the regulatory cytokine and Treg cells recruitment.

Adoptive transfer of Trichinella spiralis-activated macrophages can ameliorate both Th1- and Th2-activated inflammation in murine models

“…Schistosome infections, egg or adult worm extract suppressed Th1/17 responses and pathology and induced the Th2 cytokines IL-10 and TGF- β 32–34 . Also, our previous study demonstrated that Trichinella spiralis infection derived T reg cells were the key cells mediating the amelioration of allergic airway inflammation and DSS-induced colitis in mice 35,36 . Infection with parasites such as Brugia malayi and Schistosoma mansoni triggers M2 macrophages 37–41 .…”

Infection with Toxocara canis Inhibits the Production of IgE Antibodies to α-Gal in Humans: Towards a Conceptual Framework of the Hygiene Hypothesis?

“…The occurrence of Treg cells was observed in both the spleen and peripheral lymph nodes, where CD4 + FoxP3 + , as well as CD8 + FoxP3 + cells, were increased [82]. The anti-inflammatory role of Tregs has been confirmed in experimental infections with Trichinella spiralis, where suppression of gut inflammation was related to the increased expression of IL-10 and TGF-β and expansion of Tregs [83]. Similarly, experimental infection with A. suum suppressed lipopolysaccharide (LPS)-induced inflammation in mice through mechanisms mediated by Tregs, regulatory IL-10 and TGF-β [84].…”

Ascaris suum infection modulates inflammation: Implication of CD4+ CD25high Foxp3+ T cells and IL‐10

“…The role of Tregs in anti‐inflammatory activity has been demonstrated in other experimental infection models such as Trichinella spiralis . It was shown that mice infected with T. spiralis suppressed gut inflammation, and this suppression was associated with an increase in IL‐10 and TGF‐β and expansion of Treg cells . More recently, another group demonstrated that treatment of infected mice with E/S products of this worm showed similar profile with upregulation of Treg response and regulatory cytokines and downregulation of pro‐inflammatory cytokines …”