Costimulation of host T lymphocytes by a trypanosomal trans-sialidase: involvement of CD43 signaling |
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Authors: | Todeschini Adriane R Nunes Marise P Pires Rachel S Lopes Marcela F Previato José O Mendonça-Previato Lúcia DosReis George A |
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Institution: | Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Fiocruz, Rio de Janeiro, RJ 21944-970, Brazil. |
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Abstract: | Trans-sialidase is a membrane-bound and shed sialidase from Trypanosoma cruzi, the protozoan parasite responsible for Chagas disease. We investigated the role of soluble trans-sialidase on host CD4+ T cell activation. Trans-sialidase activated naive CD4+ T cells in vivo. Both enzymatically active and inactive recombinant trans-sialidases costimulated CD4+ T cell activation in vitro. Costimulation resulted in increased mitogen-activated protein kinase activation, proliferation, and cytokine synthesis. Furthermore, active and inactive trans-sialidases blocked activation-induced cell death in CD4+ T cells from T. cruzi-infected mice. By flow cytometry, inactive trans-sialidase bound the highly sialylated surface Ag CD43 on host CD4+ T cells. Both costimulatory and antiapoptotic effects of trans-sialidases required CD43 signaling. These results suggest that trans-sialidase family proteins are involved in exacerbated host T lymphocyte responses observed in T. cruzi infection. |
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