Natural killer cells in HIV-1 infection: role of NK cell-mediated non-cytolytic mechanisms in pathogenesis of HIV-1 infection.

Natural killer (NK) cells exhibit both cytolytic and non-cytolytic effector functions against HIV-infected targets. Their precise role in immunopathogenesis of HIV-1 infection is yet to be fully understood. This review addresses the non-cytolytic functions exhibited by NK cells, their potential role in pathogenesis of HIV-1 infection and the effect of HIV-1 viremia on NK cell functions. Activated NK cells are capable of secreting CC-chemokines and suppressing HIV-1 replication in a non-cytolytic fashion. However, HIV-1 viremia suppresses the ability of NK cells to secrete CC-chemokines. Suppression of HIV-1 viremia by highly active antiretroviral therapy (HAART) restores the ability of NK cells to secrete CC-chemokines and suppress endogenous HIV-1 replication by non-cytolytic mechanisms. Better understanding of the mechanisms involved in HIV-1-NK cell interactions would be helpful in delineating novel therapeutic strategics against HIV-1.