Toxoplasma gondii soluble tachyzoite antigen triggers protective mechanisms against fatal intestinal pathology in oral infection of C57BL/6 mice

PLoS One. 2013 Sep 24;8(9):e75138. doi: 10.1371/journal.pone.0075138. eCollection 2013.

Abstract

Toxoplasma gondii induces a potent IL-12 response early in infection that results in IFN-γ-dependent control of parasite growth. It was previously shown that T. gondii soluble tachyzoite antigen (STAg) injected 48 hr before intraperitoneal infection reduces lipoxin A4 and 5-lipoxygenase (5-LO)-dependent systemic IL-12 and IFN-γ production as well as hepatic immunopathology. This study investigated the ability of STAg-pretreatment to control the fatal intestinal pathology that develops in C57BL/6 mice orally infected with 100 T. gondii cysts. STAg-pretreatment prolonged the animals' survival by decreasing tissue parasitism and pathology, mainly in the ilea. Protection was associated with decreases in the systemic IFN-γ levels and IFN-γ and TNF message levels in the ilea and with increased TGF-β production in this tissue, but protection was independent of 5-LO and IL-4. STAg-pretreatment decreased CD4(+) T cell, NK cell, CD11b(+) monocyte and CD11b(+)CD11c(+) dendritic cell numbers in the lamina propria and increased CD8(+) T cells in the intestinal epithelial compartment. In parallel, decreases were observed in iNOS and IL-17 expression in this organ. These results demonstrate that pretreatment with STAg can induce the recruitment of protective CD8(+) T cells to the intraepithelial compartment and decrease proinflammatory immune mechanisms that promote intestinal pathology in T. gondii infection.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Analysis of Variance
  • Animals
  • Antigens, Protozoan / immunology
  • Antigens, Protozoan / pharmacology*
  • DNA Primers / genetics
  • Female
  • Flow Cytometry
  • Immunity, Cellular / immunology*
  • Immunohistochemistry
  • Interferon-gamma / immunology
  • Interleukin-17 / immunology
  • Intestines / immunology
  • Intestines / parasitology*
  • Mice
  • Mice, Inbred C57BL
  • Nitric Oxide Synthase Type II / immunology
  • Real-Time Polymerase Chain Reaction
  • Toxoplasmosis, Animal / immunology
  • Toxoplasmosis, Animal / prevention & control*
  • Tumor Necrosis Factor-alpha / immunology

Substances

  • Antigens, Protozoan
  • DNA Primers
  • Interleukin-17
  • Tumor Necrosis Factor-alpha
  • soluble tachyzoite antigen, Toxoplasma gondii
  • Interferon-gamma
  • Nitric Oxide Synthase Type II
  • Nos2 protein, mouse

Grants and funding

This work was supported by Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG) [grants 00355-11, 20/12; APQ-04312-10]; Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) [grant 481482/2010-5]; Instituto Nacional de Ciência e Tecnologia de Vacinas (INCTV); and Rede Mineira which received funding from FAPEMIG [grant 20/12]. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.