DIRECT INVOLVEMENT OF EXTRACELLULAR HIV-1 VIRIONS IN THE APOPTOSIS OF CD8+ LYMPHOCYTES - A 2-STEP MODEL

Lymphocytes of the CD8 phenotype play an important role in controlling viral burden in HIV-1 infection. Cytotoxic CD8+ T lymphocytes (CIL) can kill HIV-infected cells and in addition, are able to secrete a soluble factor that inhibits HIV replication. In most cases, HIV-infected individuals experience an unexplained CD8+ lymphopenia during the advanced stage of the disease that particularly affect HIV-1-specific CTL. It has been reported that CD8+ lymphocytes in HIV-infected individuals undergo programmed cell death or apoptosis. We now present a two-step model to explain CD8+ apoptosis, based on anchorage of HIV-1-associated MHC class 1 antigen into the envelope of extracellular viral particles.