Figure 13.

CD4 T cells are essential for protection against Zika virus (ZIKV). MHC class II-deficient (Aβ^−/−) (A,B) or CXCR5-deficient (CXCR5^−/−) and CD40L-deficient (CD40L^−/−) (C,D) mice were inoculated with 1 × 10³ pfu ZIKV i.v. and 4 weeks later were challenged with 1 × 10³ pfu ZIKV i.c. Mice were weighed and monitored daily (A,C), and on day 7 post i.c. challenge, brains were removed and viral titers were measured by a plaque assay (B,D). For all deficient mice, a group of uninfected deficient mice was included for control. Additionally, wild-type (WT) C57BL/6 mice, inoculated with 1 × 10³ pfu ZIKV i.v., and naive uninfected mice were used as positive and negative controls, respectively. The detection limit for virus in the brain was 250 pfu/g organ. Each dot represents an individual animal. The results illustrate the group medians. The weight curves depict the group medians. n = 4–5 mice/group, *p < 0.05. For the weight curves, immunized and naïve mice of the same strain have been compared, and the color of the star marks the immunized group used in the statistical comparison.