Fig 5.

Exhausted virus-specific CD8 T cells arise from the KLRG1^lo memory precursor population of effector cells. (A) KLRG1 expression on day 8 p.i. with Arm and clone 13. (B) Experimental design. Ly5.2⁺ CD44^hi D^bGP33⁺ CD8 T cells from either day 8 Arm- or day 8 clone 13-infected donor mice were sorted into KLRG1^hi and KLRG1^lo populations. Equal numbers of virus-specific KLRG1^hi- or KLRG1^lo-sorted populations were adoptively transferred into day 8 clone 13-infected recipient mice and analyzed at 1 to 2 months p.t. Approximately 2.9 × 10⁵ KLRG1^hi or KLRG1^lo D^bGP33⁺ CD8 T cells were transferred to each recipient in the Arm → clone 13 experiment, and 1.4 × 10⁵ cells were transferred in the clone 13 → clone 13 control experiment. (C to E) KLRG1^hi and KLRG1^lo CD8⁺ D^bGP33⁺ T cells from day 8 Arm-infected mice adoptively transferred into day 8 clone 13-infected recipients. (C) Representative plots of the endogenous (Ly5.2-negative [Ly5.2⁻]) and KLRG1-sorted (Ly5.2⁺) donor populations at 2 months p.t.; (D) absolute number of each transferred population on day 60 p.t.; (E) representative plots from KLRG1^lo recipient mice on day 60 p.t. The mean fluorescence of CD127 and PD-1 is shown in red or pink, with CD8⁺ CD44^lo naïve T cells shown in the gray histograms. (F and G) KLRG1^hi or KLRG1^lo CD8⁺ D^bGP33⁺ T cells from day 8 clone 13-infected mice adoptively transferred into day 8 clone 13-infected recipients. (F) Representative plots of the endogenous (Ly5.2⁻) and KLRG1-sorted (Ly5.2⁺) donor populations at 2 months p.t.; (G) absolute number of each transferred population on day 60 p.t. (H) Representative plots from KLRG1^lo recipient mice on day 60 p.t. The mean fluorescence of CD127 and PD-1 is shown in red or pink, with CD8⁺ CD44^lo naïve T cells shown in the gray histograms.