Fig. 7

IFN-β protein expression in A129 mice and neurovirulence analysis in neonate CD-1 mice. Five groups of three-week-old A129 mice (n = 6) were intraperitoneally infected with 1 × 10⁵ PFU of FSS13025 WT, FSS13025 A188V, PRVABC-59 WT, PRVABC-59 V188A virus, or phosphate-buffered saline (PBS). Mouse blood were collected at days 1, 2, and 3 p.i., sera were separated and applied for IFN-β measurement by ELISA (a), and viremia were determined by plaque assay on Vero cells (b). c Comparison of neurovirulence of FSS13025 WT, FSS13025 A188V, PRVABC-59 WT, and PRVABC-59 V188A virus in CD-1 newborn mice. Groups of one-day-old CD-1 mice (n = 8 per group) were infected with 1 × 10³ PFU through the intracranial route. Survival curves are presented. d Two groups of one-day-old CD-1 mice (n = 5) were infected with 1 × 10³ PFU of FSS13025 WT and its corresponding A188V viruses through the intracranial route. Mouse brains were harvested at days 3, 5, 7, and 9 post-infection. Viral loads in brain were determined by plaque assay on Vero cells. e, f Four groups of C57BL/6J mice (n = 4 per group) were intraperitoneally infected with 1 × 10⁵ PFU of FSS13025 WT, FSS13025 A188V, PRVABC-59 WT, or PRVABC-59 V188A virus. Mouse blood and spleen were collected at 24, 48, and 72 h post-infection. Viral RNA in sera and spleens were extracted and quantified by qRT-PCR. Data are shown as means ± SD, *P < 0.05, **P < 0.01, or no significance (n.s.) through Student’s two-sided t-test. L.O.D., limit of detection. g Summary of ZIKV non-structural proteins targeting different components of the RIG-I pathway. See text for details