Antiviral gene induction by parental IFNα, hybrid, and mutants. After treatment of macrophages (6 × 10⁶) with IFNα21b, IFNα2c, their hybrids or mutants (0.1 ng/mL) for 4 hours, total mRNA was isolated and examined for (A) PKR and (B) TRIM22 gene transcription using real-time PCR. Representative donor; n = 3. For PKR 2-tailed t test for IFNα-treated compared with control cells (None), **P < .01 (SDM1, SDM2, IFNα21b, IFNα2c) and *P < .05 (CM3, HY4). For TRIM22, *P < .05 for IFN constructs compared with untreated macrophages. Induction of PKR and TRIM22 by SDM1, SDM2, or parental IFN is not significantly different from that of CM3. (C) APOBEC3G gene expression in macrophages incubated with IFN constructs at 0.1-10 ng/mL. *P < .03 untreated vs IFN-treated constructs, *P < .03 parental IFN vs SDM1, **P < .05 IFNα21b vs SDM1. (D) APOBEC3G gene expression correlates with antiretroviral activity. Macrophages (6 × 10⁶) were treated in parallel with IFNα mutants, hybrid (HY4), or parental IFNα (1 ng/mL) for 4 hours and mRNA analyzed for APOBEC3G by RT-PCR. IFNα21b, IFNα2c, SDM1, and SDM2 significantly enhance APOBEC3G gene expression. **P < .001. For HY4 and CM3, *P < .01. APOBEC3G induction by SDM1, SDM2, IFNα2c, and IFNα21b is statistically higher than CM3, *P < .01. Representative donor, n = 3. (E) Macrophages were examined for APOBEC3A transcription after IFNα treatment (1 ng/mL). IFNα parent, hybrid, and mutants induced APOBEC3A (*P < .01), with maximal levels induced by mutant SDM1, *P < .01. Parental IFN vs SDM1, P < .05 and SDM1 vs CM3, **P = .01. Inset: APOBEC3A gene expression in monocytes exposed to IFN constructs. Untreated compared with IFN-treated constructs, *P < .05. Representative donor in duplicate n = 3. Data represent mean + SEM.