CD4 T cells have traditionally been regarded as helpers and regulators of adaptive immune
responses; however, a novel role for CD4 T cells as direct mediators of protection against
viral infections has emerged. CD4 T cells with cytolytic potential have been described for
almost 40 years, but their role in host protection against infectious disease is only beginning
to be realized. In this review, we describe the current literature identifying these cells in
patients with various infections, mouse models of viral infection and our own work …