FIG. 3.

Type I IFN-induced STAT-1 phosphorylation in PBMCs from HIV⁺/HCV⁺, HIV⁻/HCV⁺, HIV⁺/HCV⁻, and HIV⁻/HCV⁻ groups. PBMC samples were thawed, allowed to rest overnight in culture, and then left untreated or exposed to IFN-α (1,000 U/mL) for 30 min at 37°C. STAT-1 phosphorylation was measured using a cell-based ELISA as described in the “Materials and Methods” section. Results are expressed as % of basal, comparing phosphorylation in the presence of IFN-α2 with the baseline levels in untreated PBMCs. Bar graphs represent the averages and SD *P<0.05; **P<0.01.