Fig. 10

Circulating IFN-I signal-deficient CD11b⁺Ly-6C⁺ monocytes are highly permissive to JEV replication. Cells were prepared from the primary inoculation site (footpad), blood, and liver of IFN-I signal-competent and -incompetent mice 48 h after JEV infection (5 × 10⁶ ffu/mouse) via the footpad route, and used to purify CD11b⁺Ly-6C⁺ monocytes using a FACS Aria sorter. a Viral burden of circulating CD11b⁺Ly-6C⁺ monocytes in footpad, blood, and liver. Viral RNA load was determined by real-time qRT-PCR using total RNA extracted from sorted CD11b⁺Ly-6C⁺ monocytes. Viral RNA levels were expressed by JEV RNA copy number per microgram of total RNA. b Induction of RIG-I-like receptors (RLRs), IRFs, and IFN-stimulated genes (ISGs) in CD11b⁺Ly-6C⁺ monocytes derived from the footpad, blood, and liver. The mRNA levels of the indicated genes were determined by real-time qRT-PCR using total RNA extracted from sorted CD11b⁺Ly-6C⁺ monocytes. c Enhanced infection of CD11b⁺Ly-6C⁺ monocytes derived from blood of IFN-I signal-incompetent mice. CD11b⁺Ly-6C⁺ monocytes were purified from PBL collected from uninfected IFN-I signal-competent and -incompetent mice, and infected with JEV (1.0 MOI) in the presence of GM-CSF (10 ng/ml). Infectious JEV in culture media was determined by a focus-forming assay. d Enhanced JEV burden of IFN-I signal-incompetent CD11b⁺Ly-6C⁺ monocytes in BM chimeric hosts. CD11b⁺Ly-6C⁺ monocytes were purified from the footpad, blood, and liver of BM chimeric hosts 48 h pi, and used for determining JEV burden with real-time qRT-PCR. Data in bar graphs denote the mean ± SEM. Results are representative of one out of at least two individual experiments with four to five mice per group. Statistical significance *p < 0.05; **p < 0.01; ***p < 0.001 was assessed by an unpaired two-tailed Student’s t test