Evasion of cytotoxic T lymphocytes by murine cytomegalovirus

Murine cytomegalovirus causes lifelong infections with little pathology in normal host animals. Control of viral replication and prevention of patholo gy depend on both innate and adaptive immune mechanisms, and cytolytic T ly mphocytes play a key role in this process. The virus encodes a number of ge nes which alter the normal assembly of class I major histocompatability com plex proteins, and thus interfere with the ability of infected cells to pre sent antigen to CD8(+) T cells. This review will examine what is known abou t these viral genes, and present some unanswered questions regarding the ro le of CTL evasion in the viral infectious cycle.