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3100-12-31
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IMPAIRED PRODUCTION OF PRO-INFLAMMATORY CYTOKINES AND HOST RESISTANCE TO ACUTE INFECTION WITH TRYPANOSOMA CRUZI IN MICE LACKING FUNCTIONAL MYD88.
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Universidade Federal de Minas Gerais Instituto de Ciências Biológicas. Departamento de Bioquímica e Imunologia. Belo Horizonte, MG, Brasil. / Fundação Oswaldo Cruz. Centro de Pesquisas René Rachou. Belo Horizonte, MG, Brasil
Fundação Oswaldo Cruz. Centro de Pesquisas René Rachou. Belo Horizonte, MG, Brasil.
Universidade Federal de Minas Gerais Instituto de Ciências Biológicas. Departamento de Bioquímica e Imunologia. Belo Horizonte, MG, Brasil.
Universidade Federal de Minas Gerais. Escola de Farmácia. Belo Horizonte, MG, Brasil.
Department of Host Defense. Research Institute for Microbial Diseases. Osaka University, Osaka, Japan.
Universidade Federal de Minas Gerais Instituto de Ciências Biológicas. Departamento de Bioquímica e Imunologia. Belo Horizonte, MG, Brasil.
Fundação Oswaldo Cruz. Centro de Pesquisas René Rachou. Belo Horizonte, MG, Brasil.
Fundação Oswaldo Cruz. Centro de Pesquisas René Rachou. Belo Horizonte, MG, Brasil.
Fundação Oswaldo Cruz. Centro de Pesquisas René Rachou. Belo Horizonte, MG, Brasil.
Universidade Federal de Minas Gerais Instituto de Ciências Biológicas. Departamento de Bioquímica e Imunologia. Belo Horizonte, MG, Brasil.
Universidade Federal de Minas Gerais. Escola de Farmácia. Belo Horizonte, MG, Brasil.
Department of Host Defense. Research Institute for Microbial Diseases. Osaka University, Osaka, Japan.
Universidade Federal de Minas Gerais Instituto de Ciências Biológicas. Departamento de Bioquímica e Imunologia. Belo Horizonte, MG, Brasil.
Fundação Oswaldo Cruz. Centro de Pesquisas René Rachou. Belo Horizonte, MG, Brasil.
Fundação Oswaldo Cruz. Centro de Pesquisas René Rachou. Belo Horizonte, MG, Brasil.
Abstract
Studies performed in vitro suggest that activation of Toll-like receptors (TLRs) by parasite-derived molecules may initiate inflammatory responses and host innate defense mechanisms against Trypanosoma cruzi. Here, we evaluated the impact of TLR2 and myeloid differentiation factor 88 (MyD88) deficiencies in host resistance to infection with T. cruzi. Our results show that macrophages derived from TLR2 _/_ and MyD88_/_ mice are less responsive to GPI-mucin derived from T. cruzi trypomastigotes and parasites. In contrast, the same cells from TLR2_/_ still produce TNF-_, IL-12, and reactive nitrogen intermediates (RNI) upon exposure to live T. cruzi trypomastigotes. Consistently, we show that TLR2_/_ mice mount a robust proinflammatory cytokine response as well as RNI production during the acute phase of infection with T. cruzi parasites. Further, deletion of the functional TLR2 gene had no major impact on parasitemia nor on mortality. In contrast, the MyD88_/_ mice had a diminished cytokine response and RNI production upon acute infection with T. cruzi. More importantly, we show that MyD88_/_ mice are more susceptible to infection with T. cruzi as indicated by the higher parasitemia and accelerated mortality, as compared with the wild-type mice. Together, our results indicate that T. cruzi parasites elicit an alternative inflammatory pathway independent of TLR2. This pathway is partially dependent on MyD88 and necessary for mounting optimal inflammatory and RNI responses that control T. cruzi replication during the early stages of infection.
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