Immune evasion strategies of the primate lentiviruses

Individuals infected with human immunodeficiency virus (HIV) and macaques infected with simian immunodeficiency virus (SIV) make vigorous virus-specific antibody and cellular immune responses. Despite these responses, virus replication continues at all stages of infection and ultimately leads to immunological collapse, onset of opportunistic infections and death of infected hosts. Thus, the strategies by which HIV and SIV evade antiviral immune surveillance are fundamental to understanding lentiviral pathogenesis and crucial for our ability to develop effective strategies. It has become increasingly clear that the primate lentiviruses have evolved multiple and complementary mechanisms to circumvent host immune responses. Here we review these mechanisms of immune evasion considering contributions from both human and non-human primate systems.