The expression and epigenetic regulation of IRF1 gene inex vivounstimulated PBMCs from HIV-S and HIV-R individuals. (A) Intracellular IRF1 protein expression in ex vivo PBMCs from HIV-S and HIV-R (n = 6, each) participants was measured using flow cytometric analyses. Intracellular staining was performed using IRF1 specific antibody and fluorescein isothiocyanate-labeled goat antirabbit antibody. Background signal from the secondary antibody alone was within the first log (10⁰-10¹). (B) Intracellular IRF1 mRNA expression in ex vivo PBMCs from HIV-S (▵, n = 10) and HIV-R (□, n = 11) participants was assessed using quantitative RT-PCR. Bars represent mean values. **P < .005. Not significant (P > .05).