IFN coordinately enhances macrophage APOBEC3 expression and decreases susceptibility to HIV-1. (A-B) Macrophages (n = 3 donors) were cultured in the presence or absence of 10 ng/mL IFNα or IFNγ for 4 hours or 100 ng/mL LPS for 1 hour and the RNA was processed for microarray analysis. The bar graph shows the fold change for hA3G (A) and hA3A (B) across treatments. (Insets) IFNα dose-response (0, 0.1, 1, 10 ng/mL; 4 hours) induction of hA3G (A) and hA3A (B) by RT-PCR. (C) Macrophages were infected or not with HIV-1_BaL for 90 minutes, washed, and IFNα or IFNγ added once after infection at the indicated concentrations (0.1–10 ng/mL). HIV-1 infection was monitored by p24 levels in the supernatants (day 14 shown; *P < .005) (mean ± SEM).