Loss of circulating CD8α+NK cells during humanMycobacterium tuberculosisinfection

Abstract

AbstractNatural Killer (NK) cells can recognize and killMtb-infected cells in vitro, however their role after natural human exposure has not been well-studied. To identifyMtb-responsive NK cell populations, we analyzed the peripheral blood of healthy household contacts of active Tuberculosis (TB) cases and source community donors in an endemic region of Port-au-Prince, Haiti by flow cytometry. We observed higher CD8α expression on NK cells in putative resistors (IGRA-contacts) with a progressive loss of these circulating cells during household-associated latent infection and disease. In vitro assays and CITE-seq analysis of CD8α+NK cells demonstrated enhanced maturity, cytotoxic gene expression, and response to cytokine stimulation relative to CD8α-NK cells. CD8α+NK cells also displayed dynamic surface expression dependent on MHC I in contrast to conventional CD8+T cells. Together, these results support a specialized role for CD8α+NK cell populations duringMtbinfection correlating with disease resistance.