Journal of Leukocyte Biology Myeloid cells, immune suppression, tumor immunology
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A more recent version of this article appeared on April 1, 2007

Published online before print January 29, 2007
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© by The Society for Leukocyte Biology
Journal of Leukocyte Biology, doi:10.1189/jlb.1006643

Received for publication October 19, 2006.
Revised December 7, 2006.
Accepted for publication December 22, 2006.

Article

The Fas death pathway controls coordinated expansions of Type 1 CD8 and Type 2 CD4 T cells in Trypanosoma cruzi infection

Landi V. Costilla Guillermo *, Elisabeth M. Silva *, Flávia L. Ribeiro-Gomes *, Juliana De Meis *, Wânia F. Pereira *, Hideo Yagita {dagger}, George A. DosReis *, and Marcela F. Lopes *@

*Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil; and {dagger}Juntendo University School of Medicine, Tokyo, Japan

@ To whom correspondence should be addressed. E-mail: marcelal{at}biof.ufrj.br.


  Abstract

We investigated the role of the Fas ligand (FasL)/Fas death pathway on apoptosis and cytokine production by T cells in Trypanosoma cruzi infection. Anti-FasL, but not anti-TNF-{alpha} or anti-TRAIL, blocked activation-induced cell death of CD8 T cells and increased secretion of IL-10 and IL-4 by CD4 T cells from T. cruzi-infected mice. CD4 and CD8 T cells up-regulated Fas/FasL expression during T. cruzi infection. However, Fas expression increased earlier in CD8 T cells, and a higher proportion of CD8 T cells was activated and expressed IFN-{gamma} compared with CD4 T cells. Injection of anti-FasL in infected mice reduced parasitemia and CD8 T cell apoptosis and increased the ratio of CD8:CD4 T cells recovered from spleen and peritoneum. FasL blockade increased the numbers of activated T cells, enhanced NO production, and reduced parasite loads in peritoneal macrophages. Injection of anti-FasL increased IFN-{gamma} secretion by splenocytes responding to T. cruzi antigens but also exacerbated production of Type 2 cytokines IL-10 and IL-4 at a late stage of acute infection. These results indicate that the FasL/Fas death pathway regulates apoptosis and coordinated cytokine responses by Type 1 CD8 and Type 2 CD4 T cells in T. cruzi infection.

Key Words: Chagas’ disease • Th2 cytokines • apoptosis • FasL






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Copyright © 2007 by the Society for Leukocyte Biology.