STAT1 is essential for antimicrobial effector function but dispensable for gamma interferon production during Toxoplasma gondii infection.

Journal Article (Journal Article)

The opportunistic protozoan Toxoplasma gondii is a prototypic Th1-inducing pathogen inducing strong gamma interferon (IFN-gamma) cytokine responses that are required to survive infection. Intracellular signaling intermediate STAT1 mediates many effects of IFN-gamma and is implicated in activation of T-bet, a master regulator of Th1 differentiation. Here, we show that T. gondii-infected STAT1-null mice fail to upregulate the IFN-gamma-dependent effector molecules inducible nitric oxide synthase (iNOS), IGTP, and LRG-47, which are required for mice to survive infection. Both T-bet and interleukin-12 receptor beta2 (IL-12Rbeta2) failed to undergo normal upregulation in response to T. gondii. Development of IFN-gamma-producing CD4(+) and CD8(+) T lymphocytes was severely curtailed in the absence of STAT1, but a substantial level of STAT1-independent non-T-cell-derived IFN-gamma was induced. Absence of STAT1 also resulted in increased IL-4, Arg1, Ym1, and Fizz1, markers of Th2 differentiation and alternative macrophage activation. Together, the results show that T. gondii induces STAT1-dependent T-lymphocyte and STAT1-independent non-T-cell IFN-gamma production, but that effector functions of this type 1 cytokine cannot operate in the absence of STAT1, resulting in extreme susceptibility to acute infection.

Full Text

Duke Authors

Cited Authors

  • Gavrilescu, LC; Butcher, BA; Del Rio, L; Taylor, GA; Denkers, EY

Published Date

  • March 2004

Published In

Volume / Issue

  • 72 / 3

Start / End Page

  • 1257 - 1264

PubMed ID

  • 14977926

Pubmed Central ID

  • PMC356043

International Standard Serial Number (ISSN)

  • 0019-9567

Digital Object Identifier (DOI)

  • 10.1128/IAI.72.3.1257-1264.2004


  • eng

Conference Location

  • United States