Furthermore, to determine if the addition of CD8+ T cells from the vaccinated mice increases host protection, we performed adoptive transfer into AB6 mice of both pooled sera and purified CD8+ T cells collected at day 28 DPV from EILV/CHIKV-vaccinated WT and TCRδ−/− mice followed by infection with a lethal dose of WT CHIKV (Figure 4A). Here, CD8A is linked to infection.