STAT1 protein expression is impaired in the cells of P1. EBV-B cells from WT/WT, P1, K201N/WT, 1928insA/WT (WT/−), P696S/P696S, and 1928insA/1928insA (−/−) persons were stimulated with 105 IU/mL IFN-α or IFN-γ or left unstimulated for 30 minutes. (A) Western blotting was carried out with an antibody against Tyr701-phosphorylated STAT1 (P-STAT1), STAT1α (STAT1), Tyr690-phosphorylated STAT2 (P-STAT2), STAT2, and α-tubulin as a reference. (B) FACS analysis of intracellular STAT1 levels with an antibody against the N-terminus of STAT1. Solid area represents isotype control antibody. Solid line indicates STAT1 antibody. (C) FACS analysis of intracellular Tyr701-phosphorylated STAT1 levels in untreated cells (NS) or in cells treated with 105 IU/mL IFN-α or IFN-γ for 30 minutes. Solid area represents untreated cells. Thin line indicates 105 IU/mL IFN-γ stimulation; and thick line, 105 IU/mL IFN-α stimulation. Mean fluorescence intensity is indicated. The results are representative of 3 independent experiments.
