Simian immunodeficiency virus infection induces expansion of alpha4beta7+ and cytotoxic CD56+ NK cells.

Herein we demonstrate that chronic simian immunodeficiency virus (SIV) infection induces significant upregulation of the gut-homing marker alpha4beta7 on macaque NK cells, coupled with downregulation of the lymph node-trafficking marker, CCR7. Interestingly, in naïve animals, alpha4beta7 expression was associated with increased NK cell activation and, on CD16(+) NK cells, delineated a unique dual-function cytotoxic-CD107a(+)/gamma interferon (IFN-gamma)-secreting population. However, while SIV infection increased CD107a expression on stimulated CD56(+) NK cells, alpha4beta7(+) and alpha4beta7(-) NK cells were affected similarly. These findings suggest that SIV infection redirects NK cells away from the lymph nodes to the gut mucosae but alters NK cell function independent of trafficking repertoires.