CD8.

HIV-1 infection in humans results in an early and progressive NK cell dysfunction and an accumulation of an 'anergic' CD56 CD16 NK subset, which is characterised by low natural cytotoxicity receptor expression and low cytokine producing capacity. In contrast to humans, chimpanzee NK cells do not display a distinguishable CD56 and CD56 subset but, as shown here, could be subdivided into functionally different CD8 and CD8 subsets. The CD8 NK cells expressed significantly higher levels of triggering receptors including NKp46 and, upon in vitro activation, produced more IFN-γ, TNF-α and CD107 than their CD8 counterparts. In addition, chimpanzee CD8 NK cells had relatively high levels of HLA-DR expression, suggestive of an activated state. Killing inhibitory receptors were expressed only at low levels; however, upon in vitro stimulation, they were up-regulated in CD8 but not in CD8 NK cells and were functionally capable of inhibiting NKp30-triggered killing. In contrast to HIV-1-infected humans, infected chimpanzees maintained their dominant CD8 NK cell population, with high expression of natural cytotoxicity receptors. [ABSTRACT FROM AUTHOR]