Expression of gp91phox and p22phox in IFNγ-exposed classically activated mouse microglial BV-2 cells. BV-2 cells were exposed to vehicle (vehi), IFNγ, IL-4, or IL-10. The levels of microglial phenotype markers (NOx, TNFα, arginase activity, iNOS, and Ym1), gp91phox, and p22phox were evaluated in medium or cell homogenates 24 hours later. Production of (A) NOx and (B) TNFα were determined in the media. (C) Expression of iNOS, Ym1, gp91phox, and p22phox was determined by immunoblotting with reduced samples. ß-Actin levels were used as an internal control. IFNγ-exposed BV-2 cells had increased NOx, TNFα, and iNOS levels, all of which are classical activating markers of the microglial phenotype. In contrast, IL-4-exposed BV-2 cells had increased arginase activity and Ym1 levels, which are alternative markers of activation. Gp91phox and p22phox levels were increased only in IFNγ-exposed BV-2 cells, suggesting induction by classically activated microglial cells.