Foxp3+ regulatory T cells among tuberculosis patients: impact on prognosis and restoration of antigen specific IFN-γ producing T cells

PLoS One. 2012;7(9):e44728. doi: 10.1371/journal.pone.0044728. Epub 2012 Sep 19.

Abstract

CD4(+)CD25(+)Foxp3(+) regulatory T cells (Treg) and programmed death-1 (PD-1) molecules have emerged as pivotal players in immune suppression of chronic diseases. However, their impact on the disease severity, therapeutic response and restoration of immune response in human tuberculosis remains unclear. Here, we describe the possible role of Treg cells, their M. tuberculosis driven expansion and contribution of PD-1 pathway to the suppressive function of Treg cells among pulmonary tuberculosis (PTB) patients. Multicolor flow cytometry, cell culture, cells sorting and ELISA were employed to execute the study. Our results showed significant increase in frequency of antigen-reactive Treg cells, which gradually declined during successful therapy and paralleled with decline of M. tuberculosis-specific IL-10 along with elevation of IFN-γ production, and raising the IFN-γ/IL-4 ratio. Interestingly, persistence of Treg cells tightly correlated with MDR tuberculosis. Also, we show that blocking PD-1/PD-L1 pathway abrogates Treg-mediated suppression, suggesting that the PD-1/PD-L1 pathway is required for Treg-mediated suppression of the antigen-specific T cells. Treg cells possibly play a role in dampening the effector immune response and abrogating PD-1 pathway on Treg cells significantly rescued protective T cell response, suggesting its importance in immune restoration among tuberculosis patients.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • CD4-Positive T-Lymphocytes / immunology
  • CD4-Positive T-Lymphocytes / metabolism
  • Enzyme-Linked Immunosorbent Assay
  • Female
  • Flow Cytometry
  • Forkhead Transcription Factors / metabolism*
  • Humans
  • Interferon-gamma / metabolism*
  • Interleukin-4 / metabolism
  • Male
  • Middle Aged
  • Programmed Cell Death 1 Receptor / metabolism
  • T-Lymphocytes / immunology*
  • T-Lymphocytes / metabolism*
  • T-Lymphocytes, Regulatory / immunology*
  • T-Lymphocytes, Regulatory / metabolism*
  • Tuberculosis, Pulmonary / immunology*
  • Tuberculosis, Pulmonary / metabolism
  • Tuberculosis, Pulmonary / pathology*
  • Young Adult

Substances

  • FOXP3 protein, human
  • Forkhead Transcription Factors
  • PDCD1 protein, human
  • Programmed Cell Death 1 Receptor
  • Interleukin-4
  • Interferon-gamma

Grant support

The study was supported by the Department of Biotechnology and the Indian Council of Medical Research, Government of India, New Delhi, India. For this study the funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.