FIG. 3.

Induction of IL-6 by mutant viruses in wild-type cells and by wild-type HSV-1 in macrophages unable to activate PKR in response to double-stranded RNA. (A) RAW 264.7 cells were seeded and left overnight to settle. The cells were treated with 10 IU of IFN-γ per ml and 3 × 10⁶ PFU of wild-type or mutant HSV-1 per ml. After 4 h of treatment, total RNA was isolated and subjected to RT-PCR using oligo(dT)₁₅ RT-priming and PCR primers specific for murine β-actin and IL-6. (B) The RAW 264.7-derived cell lines pBK-CMV and PKR-M7 were seeded as above. Sixteen hours later the cells were treated with 10 IU of IFN-γ per ml and 3 × 10⁶ PFU of HSV-1 (KOS) per ml. After 4 h of treatment, total RNA was extracted and analyzed for IL-6 and β-actin by RT-PCR.