Immunosuppressive components of Ascaris suum down-regulate expression of costimulatory molecules and function of antigen-presenting cells via an IL-10-mediated mechanism
✍ Scribed by Sandriana R. Silva; Jacqueline F. Jacysyn; Mahasti S. Macedo; Eliana L. Faquim-Mauro
- Book ID
- 102163844
- Publisher
- John Wiley and Sons
- Year
- 2006
- Tongue
- English
- Weight
- 447 KB
- Volume
- 36
- Category
- Article
- ISSN
- 0014-2980
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✦ Synopsis
Abstract
High‐molecular‐weight components (PI) of Ascaris suum suppress both cell‐mediated and humoral responses against ovalbumin (OVA) via an IL‐4/IL‐10‐dependent mechanism. The aim of this work was to investigate the effect of PI on the ability of APC to activate T cells and the role of IL‐10 in this process. Flow cytometry analyses of MHC class II, CD80, CD86 and CD40 molecules on LN cells from mice immunized with OVA or OVA+PI showed that PI inhibits expression of these molecules on unfractionated cells and on purified CD11c^+^ cells. A low proliferative response was obtained when OVA‐specific TCR‐Tg T cells were incubated with CD11c^+^ cells from OVA+PI‐immunized mice pulsed with OVA, when compared to those incubated with cells from OVA‐immunized mice. Similar results were obtained using as APC CD11c^+^ cells from OVA‐immunized mice pulsed with OVA+PI, which also expressed less of the four markers. The inhibitory effect of PI on both the expression of costimulatory molecules and the induction of T cell proliferation was abolished in IL‐10‐deficient mice. Our data indicate that the potent immunosuppressive effect of A. suum extract components on the host immune system is primarily related to their property of down‐regulating the Ag‐presenting ability of DC via an IL‐10‐mediated mechanism.