Antiretroviral therapy partly reverses the systemic and mucosal distribution of NK cell subsets that is altered by SIVmac251 infection of macaques

- NK subsets in acute and chronic SIV infection.
- NK and Antiretroviral Therapy in SIV infection.
- NKp44+ subset and NKG2A+ NK cells in blood and the gut.

We characterized three subsets of NK cells in blood, and two subsets in mucosal tissues. SIVmac251 infection increased total and CD16+ NK cells in the blood. In the rectum, we observed a significant increase in total and NKG2A+ NK cells during SIV infection. In contrast, the NKp44+ subset significantly depleted in acute infection and continued to decline in frequency during chronic phase. During SIV infection, blood CD16 and mucosal NKG2A+ subsets had increased cytotoxic potential. Intriguingly, the NKp44+ NK cell subtype that likely mediates mucosal homeostasis via the production of cytokines, acquired cytotoxicity. Antiretroviral therapy significantly increased the frequency of mucosal NKG2A+ NK cells and peripheral CD16+ NK cells. However, it failed to restore the normal frequency of NKp44+ NK cells in the rectum. Thus, SIVmac251 infection causes changes in the distribution and function of NK cells and antiretroviral therapy during chronic infection only partially restores NK homeostasis and function.