At an early time point after ZIKV infection of pregnant dams, CD8+ T cell depletion abrogated DENV-immune-mediated protection in maternal tissues and the maternal–fetal interface (i.e., decidua/placenta) despite having no effect on maternal viremia, suggesting that DENV-elicited memory CD8+ T cells preferentially exert their effects in tissues rather than in circulation. The gene discussed is CD8A; the disease is Zika virus infectious disease.