Of mice and men: cytotoxic T cells and AIDS pathogenesis.

CD8+ cytotoxic T lymphocytes (CTLs) represent a first line of defense against HIV infection, although their precise role in disease pathogenesis remains enigmatic. They play an important part in viral control but may also contribute to disease progression through destruction of CD4+ helper T cells. The role of CTLs in lymphocytic choriomeningitis virus (LCMV) infection in mice has been studied extensively, and the effects of CTL activity on host and virus are well defined. Although LCMV is not a retrovirus, it shares salient features with HIV, including a wide tropism, a capacity to persist, and genetic instability. The diseases caused by LCMV and HIV are linked by common immune effector mechanisms and, potentially, immunopathologies. Understanding the well-characterized immune responses in LCMV infection may therefore cast light on the role of CTLs in HIV disease.