Toxoplasma gondii clonal strains all inhibit STAT1 transcriptional activity but polymorphic effectors differentially modulate IFNγ induced gene expression and STAT1 phosphorylation.

ABSTRACT: Host defense against the parasite Toxoplasma gondii requires the cytokine interferon-gamma (IFNγ). However, Toxoplasma inhibits the host cell transcriptional response to IFNγ, which is thought to allow the parasite to establish a chronic infection. It is not known whether all strains of Toxoplasma block IFNγ-responsive transcription equally and whether this inhibition occurs solely through the modulation of STAT1 activity or whether other transcription factors are involved. We find that strains from three North American/European clonal lineages of Toxoplasma, types I, II, and III, can differentially modulate specific aspects of IFNγ signaling through the polymorphic effector proteins ROP16 and GRA15. STAT1 tyrosine phosphorylation is activated in the absence of IFNγ by the Toxoplasma kinas

SUBMITTER: Rosowski EE 

PROVIDER: S-EPMC3519884 | biostudies-literature | 2012

REPOSITORIES: biostudies-literature