Distinct functions of antigen-specific CD4 T cells during murine Mycobacterium tuberculosis infection

William W. Reiley, Shahin Shafiani, Susan T. Wittmer, Glady's Tucker-Heard, James J. Moon, Marc K. Jenkins, Kevin B. Urdahl, Gary M. Winslow, David L. Woodland

Research output: Contribution to journalArticlepeer-review

122 Scopus citations

Abstract

The immune response elicited after Mycobacterium tuberculosis (Mtb) infection is critically dependent on CD4 T cells during both acute and chronic infection. How CD4 T-cell responses are maintained throughout infection is not well understood, and evidence from other infection models has suggested that, under conditions of chronic antigen stimulation, T cells can undergo replicative exhaustion. These findings led us to determine whether subpopulations of CD4 T cells existed that displayed markers of terminal differentiation or exhaustion during murine Mtb infection. Analysis of antigen- specific effector CD4 T cells revealed that programmed death- 1 (PD-1) and the killer cell lectin-like receptor G1 (KLRG1) delineated subpopulations of T cells. PD-1-expressing CD4 T cells were highly proliferative, whereas KLRG1 cells exhibited a short lifespan and secreted the cytokines IFNYγ and TNFα. Adoptive transfer studies demonstrated that proliferating PD-1-positive CD4 T cells differentiated into cytokine-secreting KLRG1-positive T cells, but not vice versa. Thus, proliferating PD-1-positive cells are not exhausted, but appear to be central to maintaining antigen-specific effector T cells during chronic Mtb infection. Our findings suggest that antigen- specific T-cell responses are maintained during chronic mycobacterial infection through the continual production of terminal effector cells from a proliferating precursor population.

Original languageEnglish (US)
Pages (from-to)19408-19413
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume107
Issue number45
DOIs
StatePublished - Nov 9 2010

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