FTI treatment inhibits generation of IFN-γ protein. Th1 (pGL10) cells were preincubated with 10 μM of FTI CP 390392 or culture medium for 24 hours followed by stimulation with PMA/ionomycin at 37°C for the indicated time periods (0–25 hours). (A) After indicated intervals, cells were permeabilized and IFN-γ protein was detected by intracellular antibody staining. Fluorescence intensity was determined by fluorescence-activated cell sorter (FACS) analysis. (B) In parallel, stimulated cells were lysed, separated on SDS-PAGE, and analyzed by Western blotting using anti–IFN-γ Abs. Anti-ERK was used as a loading control.