Differentiation of antigen-specific T cells with limited functional capacity during Mycobacterium tuberculosis infection

Infect Immun. 2014 Jan;82(1):132-9. doi: 10.1128/IAI.00480-13. Epub 2013 Oct 14.

Abstract

Despite the generation of Mycobacterium tuberculosis-specific T cell immune responses during the course of infection, only 5 to 10% of exposed individuals develop active disease, while others develop a latent infection. This phenomenon suggests defective M. tuberculosis-specific immunity, which necessitates more careful characterization of M. tuberculosis-specific T cell responses. Here, we longitudinally analyzed the phenotypes and functions of M. tuberculosis-specific T cells. In contrast to the functional exhaustion of T cells observed after chronic infection, M. tuberculosis-specific CD8(+) T cells differentiated into either effector (CD127(lo) CD62L(lo)) or effector memory (CD127(hi) CD62L(lo)) cells, but not central memory cells (CD127(hi) CD62L(hi)), with low programmed death 1 (PD-1) expression, even in the presence of high levels of bacteria. Additionally, M. tuberculosis-specific CD8(+) and CD4(+) T cells produced substantial levels of tumor necrosis factor alpha (TNF-α) and gamma interferon (IFN-γ), but not interleukin 2 (IL-2), upon in vitro restimulation. Among M. tuberculosis-specific CD8(+) T cells, CD127(hi) effector memory cells displayed slower ongoing turnover but greater survival potential. In addition, these cells produced more IFN-γ and TNF-α and displayed lytic activity upon antigen stimulation. However, the effector function of M. tuberculosis-specific CD8(+) CD127(hi) effector memory T cells was inferior to that of canonical CD8(+) CD127(hi) memory T cells generated after acute lymphocytic choriomeningitis virus infection. Collectively, our data demonstrate that M. tuberculosis-specific T cells can differentiate into memory T cells during the course of M. tuberculosis infection independent of the bacterial burden but with limited functionality. These results provide a framework for further understanding the mechanisms of M. tuberculosis infection that can be used to develop more effective vaccines.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antigens, Bacterial / immunology
  • Antigens, Differentiation / immunology
  • Bacterial Load
  • CD4-Positive T-Lymphocytes / immunology*
  • CD8-Positive T-Lymphocytes / immunology*
  • Cell Differentiation / immunology
  • Chronic Disease
  • Disease Models, Animal
  • Female
  • Immunity, Cellular / immunology
  • Immunologic Memory / physiology
  • Interferon-gamma / metabolism
  • Longitudinal Studies
  • Mice
  • Mice, Inbred C57BL
  • Mycobacterium tuberculosis / immunology*
  • Phenotype
  • T-Lymphocytes, Helper-Inducer / immunology
  • Tuberculosis / immunology*
  • Tumor Necrosis Factor-alpha / metabolism

Substances

  • Antigens, Bacterial
  • Antigens, Differentiation
  • Tumor Necrosis Factor-alpha
  • Interferon-gamma