CD4 and infection: Nano2/4 signaled the protective immunity in pregnancy that was evidenced by (a) expansion of CD4+Tem and CD4+Tcm subsets after immunization, (b) functional activation of CD4+T-cell subsets upon in vitro stimulation, and (c) increased proliferation of CD4+Tem, CD4+Tcm and CD8+Tcm subsets producing IFNγ and cytolytic molecules (PRF1, GZB) after challenge infection.