Cardif-mediated signaling controls the initial innate response to dengue virus in vivo - PubMed

FIG. 4.

Delayed type I IFN responses to DENV infection in Cardif^−/− mice. (A) Sera of WT and Cardif^−/− mice that were infected i.v. with 10¹¹ GE of S221 were collected and analyzed for IFN-α and IFN-β by enzyme-linked immunosorbent assay. Each time point represents three to eight mice per group, with means ± standard errors of the means. Differences in IFN levels between WT and Cardif^−/− mice at 12 h (IFN-α, P = 0.0002; IFN-β, P = 0.0005), 18 h (IFN-α, P < 0.0001; IFN-β, P = 0.0011), and 24 h (IFN-α, P = 0.0051) were statistically significant using the unpaired t test. Baseline values in naive WT and Cardif^−/− mice were 44.8 pg/ml and 41.9 pg/ml, respectively. (B) At the indicated times postinfection, WT and Cardif^−/− mice infected with 1 × 10¹¹ GE of S221 were sacrificed, and total RNA was extracted from spleens. Levels of IFN-α and IFN-β mRNA were determined by qRT-PCR using SYBR green (Applied Biosystems) and normalized to ribosomal gene L32 mRNA in parallel reactions. Differences in IFN mRNA between WT and Cardif^−/− mice at 3 h (IFN-α, P = 0.0013; IFN-β, P = 0.0009), 6 h (IFN-α, P < 0.0001; IFN-β, P < 0.0001), 12 h (IFN-α, P < 0.0001; IFN-β, P < 0.0001), 18 h (IFN-α, P = 0.0012), and 36 h (IFN-α, P = 0.0022; IFN-β, P = 0.0032) were statistically significant using the unpaired t test. Each time point represents three to six mice per group, with means ± standard errors of the means. (C) WT and Cardif^−/− mice infected with 1 × 10¹¹ GE of S221 were sacrificed, and total RNA was extracted from PLN, MLN, and bone marrow. IFN-α levels were determined by qRT-PCR and normalized to L32 mRNA, as previously described. Differences in IFN mRNA between WT and Cardif^−/− mice in the PLN (12 h, P = 0.0039), MLN (12 h, P = 0.0011; 18 h, P = 0.0013), and bone marrow (12 h, P = 0.0162; 18 h, P = 0.0196) were statistically significant using the unpaired t test. Each time point represents three to five mice per group, with means ± standard errors of the means, and the limit of detection for each (PLN, 0.68; MLN, 0.11; bone marrow, 1.18) is denoted by a dotted line.