Ifnar1−/−HLA-DRB1*0101 mice were infected intraperitoneally with 2 × 103 FFU of DENV2 strain S221 for 7 days. Splenocytes were stimulated in vitro for 6 h with the indicated ZIKV-derived peptides that were predicted to bind HLA-DRB1*0101, and the frequencies of cytokine-producing cells were detected using the ICS assay.
(A) Representative flow cytometry contour plots.
(B and C) Quantification of CD4+ T cells producing IFNγ, TNF, or IFNγ plus TNF (B) or IL-2 (C). Data represent the mean ± SEM of three independent experiments (n = 3–4 mice/experiment; total 10 mice). **p < 0.01, ***p < 0.001, ****p < 0.0001 by one-tailed Mann-Whitney test with a B-H adjusted p value (FDR) < 10%. Negative and positive refer to cells incubated in medium alone or with PMA and ionomycin, respectively.