Immune control and prevention of chronic Friend retrovirus infection.

T cells are critical to control acute infection of a host with retroviruses but they are usually unable to prevent the development of chronic infections. This review summarizes studies from the Friend virus mouse model that reveal some of the mechanisms by which T cells control chronic retroviral infection, and also reveal why these responses ultimately fail to fully eradicate infection. Also summarized are findings from vaccine studies demonstrating the immunological requirements for the prevention of chronic retroviral infection. The implications of these findings for chronic infections in humans are discussed.