IRF1 and infection: While only RH(I) infection induced the tyrosine phosphorylation of STAT1 in the absence of IFNγ (Fig. 3A), RH(I) and RHΔrop16 parasites both completely inhibited IFNγ induced IRF1 expression (Fig. 3A), indicating that ROP16 induced phospho-STAT1Tyr is not transcriptionally active and that ROP16 is not required for the ability of Toxoplasma infection to block IFNγ induced STAT1 mediated gene expression.