Evasion of Antiviral Innate Immunity by Theiler's Virus L* Protein through Direct Inhibition of RNase L
Figure 2
Theiler's virus L* protein inhibits the 2–5A/RNase L pathway in infected peritoneal macrophages.
A. Peritoneal macrophages prepared from RNase L −/− (central panel) or RNase L+/+ (left) C57BL/6 mice and, as an additional control, from RNase L+/+ 129/Sv mice (right), were mock-infected or infected at a MOI of 20 with VV18 (L* WT), TM770 (L* 1–92) or FS58 (L* 1–12). Nine hours post infection, total cell RNA was extracted and analyzed on RNA chips. For control purposes, peritoneal macrophages were also transfected with 2.5 µg/ml poly(I:C) for 7 h before total cell RNA extraction. Prominent rRNA cleavage products are indicated. B. Replication levels of wild-type or L*-mutant viruses in peritoneal macrophages. Peritoneal macrophages isolated from indicated mouse strains were plated for four days and infected as in (A). Viral RNA was quantified by quantitative RT-PCR. Histograms show the mean and SD of viral cDNA copies detected in samples from a representative triplicate infection experiment. Values for mock samples were lower than the detection limit (10 cDNA copies). The experiment was repeated twice, using two independent productions of viruses and macrophages.