Our in vitro results suggest a possibility of virus-specific CD4+ T-cell activation by NAbs, and neutralizing activity may contribute to protection of these virus-specific CD4+ T cells from SIV trans-infection via DCs [37]–[38], possibly counteracting the abrogation of the optimal concert of adaptive immunity between CD4+ T and CD8+ T cells usually observed in the natural course of pathogenic immunodeficiency virus infection [23], [25], [39]. Here, CD4 is linked to infection.