IFNG and Zika virus infectious disease: As expected, IFN-γ+ Tfh cells expressed higher levels of T-bet, Eomes and CXCR3 than IFN-γ− conventional Tfh cells, but lower than Th1 cells (Fig. 2d); and T-bet was slightly downregulated in IFN-γ+ Tfh cells on day 14 compared with that on day 7 after ZIKV infection (Supplementary Fig. 5d).