STAT1 and infection: The inconsistencies in these results may reflect experimental differences such as the use of transfected plasmids or stably-expressing cell lines versus infection, the use of cells from different hosts and in particular from non-host species, and the use of cells that are competent to express type 1 IFN, which can confound results since Stat1 expression is strongly up-regulated by type 1 IFN.