Id2 Influences Differentiation of Killer Cell Lectin-like Receptor G1hi Short-Lived CD8+ Effector T Cells

Abstract

CD8+ T cells play a crucial role in the clearance of intracellular pathogens through the generation of cytotoxic effector cells that eliminate infected cells and long-lived memory cells that provide enhanced protection against reinfection. We have previously shown that the inhibitor of E protein transcription factors, Id2, is necessary for accumulation of effector and memory CD8+ T cells during infection. In this study, we show that CD8+ T cells lacking Id2 did not generate a robust terminally differentiated killer cell lectin-like receptor G1 (KLRG1)hi effector population, but displayed a cell-surface phenotype and cytokine profile consistent with memory precursors, raising the question as to whether loss of Id2 impairs the differentiation and/or survival of effector memory cells. We found that deletion of Bim rescued Id2-deficient CD8+ cell survival during infection. However, the dramatic reduction in KLRG1hi cells caused by loss of Id2 remained in the absence of Bim, such that Id2/Bim double-deficient cells form an exclusively KLRG1loCD127hi memory precursor population. Thus, we describe a role for Id2 in both the survival and differentiation of normal CD8+ effector and memory populations.