The immune response to CMV infection and vaccination in mice, monkeys and humans: recent developments.

The immune response to CMV is characterized by extremely large T cell and antibody responses that persist for a lifetime, but do not prevent superinfection with other CMV strains. This makes generation of a vaccine against CMV very difficult, but has facilitated development of CMV-vectored vaccines, which have shown promise in mouse tumor models and in monkey models of infectious disease. The serendipitous use of a mutant rhesus CMV vector for the SIV vaccine elicited extraordinary, CD8 T cell responses restricted by MHCII and non-classical MHCI molecules which apparently provide protection against SIV. CMV-specific CD8 T cell responses in the mouse model are driven by antigen and live out their lives primarily within the intravascular compartment.