FIG. 1.

SINV neurovirulent strain AR86 efficiently inhibits STAT1/2 activation in response to type I and type II IFNs. Vero cells, which respond to but do not secrete type I IFNs, were infected at an MOI of 10 PFU/cell with SINV strains AR86 (S300), TR339, and Girdwood (G100). At 6, 8, or 10 hpi, the cells were treated with IFN-β or IFN-γ (1,000 U/ml) for 20 min, after which whole-cell lysates were prepared. Equivalent protein from the samples was then subjected to immunoblotting using the indicated antibodies. Four independent experiments yielded results consistent with the data shown. *, the phospho-specific STAT2 antibody used (Upstate) is directed against mouse STAT2 phosphorylated at tyrosine 689 but cross-reacts with the corresponding position of human (primate) STAT2 (pY-690).