Trypanosoma cruzi immune evasion mediated by host cell-derived microvesicles

J Immunol. 2012 Feb 15;188(4):1942-52. doi: 10.4049/jimmunol.1102053. Epub 2012 Jan 18.

Abstract

The innate immune system is the first mechanism of vertebrate defense against pathogen infection. In this study, we present evidence for a novel immune evasion mechanism of Trypanosoma cruzi, mediated by host cell plasma membrane-derived vesicles. We found that T. cruzi metacyclic trypomastigotes induced microvesicle release from blood cells early in infection. Upon their release, microvesicles formed a complex on the T. cruzi surface with the complement C3 convertase, leading to its stabilization and inhibition, and ultimately resulting in increased parasite survival. Furthermore, we found that TGF-β-bearing microvesicles released from monocytes and lymphocytes promoted rapid cell invasion by T. cruzi, which also contributed to parasites escaping the complement attack. In addition, in vivo infection with T. cruzi showed a rapid increase of microvesicle levels in mouse plasma, and infection with exogenous microvesicles resulted in increased T. cruzi parasitemia. Altogether, these data support a role for microvesicles contributing to T. cruzi evasion of innate immunity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Membrane / metabolism*
  • Cells, Cultured
  • Chagas Disease / immunology*
  • Chagas Disease / parasitology
  • Chagas Disease / pathology
  • Complement C3-C5 Convertases / metabolism*
  • Cytoplasmic Vesicles / immunology*
  • Cytoplasmic Vesicles / metabolism*
  • Erythrocytes / ultrastructure
  • Host-Pathogen Interactions
  • Humans
  • Immune Evasion*
  • Immunity, Innate
  • Lymphocytes / immunology
  • Mice
  • Mice, Inbred BALB C
  • Monocytes / immunology
  • Transforming Growth Factor beta / metabolism
  • Trypanosoma cruzi / immunology*
  • Trypanosoma cruzi / metabolism
  • Trypanosoma cruzi / pathogenicity

Substances

  • Transforming Growth Factor beta
  • Complement C3-C5 Convertases