Non-M3, MHC Ib-restricted CD8⁺ T cells preferentially expand in the lung and express elevated levels of KLRG1 during Mtb infection.

<p>WT and K^b-/-D^b-/-M3^-/- mice were sacrificed at indicated time-points, single cells from the lung and spleen were prepared for phenotypic analysis of CD8⁺ T cells by flow cytometry. (A) Kinetic changes of total number of CD8⁺ T cells in the lung and spleen from C57BL/6 (n = 4–9) and K^b-/-D^b-/-M3^-/- (n = 7–9) mice after infection. Numbers in bracket indicate fold changes of expansion at indicated time points after infection. (B) Kinetic changes of total number of CD44^hiCD62L^loCD8⁺ effector T cells (T_EFF) in lung and spleen from C57BL/6 (n = 4–6) and K^b-/-D^b-/-M3^-/- (n = 4–7) mice during infection. (C, D) Representative histograms show the expression of KLRG1 (C) and PD-1 (D) on CD8 T_EFF cells from the lung at day 0 and day 60 post-infection. Grey solid areas indicate isotype control. Data shown are representative of three independent experiments. (E) Representative dot plots depict CD127 expression on CD8⁺ effector and memory (CD44^hiCD62L^hi) cells in the lungs of indicated mice before infection or at day 60 post-infection. (F, G) Bar graphs depict the mean ± SEM of the percentage (F) and total number (G) of CD8⁺ Tcm. (CD127⁺CD44^hiCD62L^hi) cells in the lung of C57BL/6 (n = 4–6) and K^b-/-D^b-/-M3^-/- (n = 4–7) at indicated time points after infection. *<i>P</i> <0.05, **<i>P</i> <0.01, ***<i>P</i> <0.001.