KLRG1⁺ T cells lack proliferative capacity.

(A) The indicated 3 CD8 T-cell populations from PBLs of a healthy adult donor were isolated by cell sorting, according to their expression of KLRG1 and CD28. Afterward, cells were labeled with CFSE and were stimulated with PHA/IL-2 in the presence of unlabeled autologous feeder cells. Cell division was analyzed by flow cytometry after 4 days. Histograms display CFSE profiles of the populations indicated. The left peak in each histogram represents unlabeled autologous feeder cells. (B) The indicated 3 CD4 T-cell populations from PBLs were isolated by cell sorting according to their expression of KLRG1 and CD45RA. Afterward, CFSE-labeled cells were stimulated with PHA/IL-2 in the presence of unlabeled autologous feeder cells, and cell division was analyzed after 5 days. The left peak in each histogram represents unlabeled autologous feeder cells. (C) Total PBLs were labeled with CFSE and were stimulated with PHA and the indicated cytokines in vitro. Three and 5 days later, cultures were stained with mAbs to CD8 and KLRG1. Dot plots shown are gated on CD8 T cells.