Interleukin-21 Induces Short-Lived Effector CD8 + T Cells but Does Not Inhibit Their Exhaustion after Mycobacterium bovis BCG Infection in Mice

Interleukin 21 (IL-21) is a pleiotropic common cytokine receptor γ chain cytokine that promotes the effector functions of NK cells and CD8+ T cells and inhibits CD8+ T cell exhaustion during chronic infection. We found that the absolute number of short-lived effector CD8+ T cells (SLECs) (KLRG1high CD127low ) decreased significantly in IL-21 receptor-deficient (IL-21R−/− ) mice duringMycobacterium bovis bacillus Calmette-Guérin (BCG) infection.