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Costimulation of Host T Lymphocytes by a Trypanosomal trans -Sialidase: Involvement of CD43 Signaling

2002; American Association of Immunologists; Volume: 168; Issue: 10 Linguagem: Inglês

10.4049/jimmunol.168.10.5192

1550-6606

Adriane R. Todeschini, Marise P. Nunes, Rachel S. Pires, Marcela F. Lopes, José O. Previato, Lúcia Mendonça‐Previato, George A. DosReis,

Research on Leishmaniasis Studies

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.