The fraction of CD161+ subset is correlated with IL-23 responsiveness in CD8+CD45RO+ memory T cells and with age.

<p>(A) The fraction of the CD161+ subset in CD8+CD45RO+ memory T cells is positively correlated (n = 35, r = 0.80; p<0.001) with IL-23 responsiveness, measured by whole blood phospho-flow for IL-23-mediated pSTAT3 induction (log2). (B) Upper panel: FACS-sorted CD3+CD8+CD45RO+ CD161+ or CD161− T cells were stimulated with or without 100 ng/ml IL-23 for 15 minutes and pSTAT3 induction was assessed by phospho-flow. Representative flow cytometry plots are shown from one of the three individuals assessed. IL-23 responsive CD8+CD45RO+ T cells are confined to the CD161+ fraction. Lower panel: the percent IL-23R-expressing cells in CD8+CD161− or CD8+CD161+ cells are shown. Representative flow cytometry plots are shown from one of the two individuals assessed. (C) The fraction of the CD161+ subset in CD8+CD45RO+ memory T cells gradually declines with age (n = 35, r = −0.34, p = 0.05).