All vaccines currently in use, as well as those in advanced development stages, are designed to induce protective antibody responses.1 And while humoral immunity is a highly efficient protective mechanism, it is reasoned that vaccines that are also capable of inducing CD8+ T cells will likely increase the protective efficacy of vaccine-induced antibody responses.5, 6 Indeed, CD8+ T cells will complement the humoral protective activity by exerting their anti-microbial effects against intracellular stages of infection, which are not commonly affected by circulating antibodies. This evidence concerns the gene CD8A and infection.