TLR4-mediated IRF3 nuclear translocation and STAT1 phosphorylation is preserved in HIV⁺ macrophages. Lipid A–mediated nuclear translocation of IRF3 is intact comparing U937 human macrophages and HIV⁺ U1 cells. (A) U937 and (B) U1 macrophages were incubated with lipid A (10 μg/mL) over time, and then nuclear and cytoplasmic extract was isolated and probed with anti-IRF3 antibody by Western blot. Western blot is a representative of 4 independent experiments with similar results. (C) Preserved lipid A–mediated phosphorylation of STAT1 in HIV⁺ human macrophages. U937 and U1 macrophages were incubated with lipid A (10 μg/mL) over time, and detergent-soluble cell extracts were probed with anti–phosphorylated STAT1 antibody by Western blot. Membranes were stripped and probed with anti–β-actin for protein loading. Western blot is a representative experiment of 3 independent experiments with similar results. Quantitative densitometric analysis of IRF3 nuclear extract bands (A-B) and phosphorylated-STAT1 bands (C) are displayed directly beneath the blots. Error bars indicate SEM.