PD-1 Expression and Cytokine Secretion Profiles of Mycobacterium tuberculosis-Specific CD4+ T-Cell Subsets; Potential Correlates of Containment in HIV-TB Co-Infection

PLoS One. 2016 Jan 12;11(1):e0146905. doi: 10.1371/journal.pone.0146905. eCollection 2016.

Abstract

HIV co-infection is an important risk factor for tuberculosis (TB) providing a powerful model in which to dissect out defective, protective and dysfunctional Mycobacterium tuberculosis (MTB)-specific immune responses. To identify the changes induced by HIV co-infection we compared MTB-specific CD4+ responses in subjects with active TB and latent TB infection (LTBI), with and without HIV co-infection. CD4+ T-cell subsets producing interferon-gamma (IFN-γ), interleukin-2 (IL-2) and tumour necrosis factor-alpha (TNF-α) and expressing CD279 (PD-1) were measured using polychromatic flow-cytometry. HIV-TB co-infection was consistently and independently associated with a reduced frequency of CD4+ IFN-γ and IL-2-dual secreting T-cells and the proportion correlated inversely with HIV viral load (VL). The impact of HIV co-infection on this key MTB-specific T-cell subset identifies them as a potential correlate of mycobacterial immune containment. The percentage of MTB-specific IFN-γ-secreting T-cell subsets that expressed PD-1 was increased in active TB with HIV co-infection and correlated with VL. This identifies a novel correlate of dysregulated immunity to MTB, which may in part explain the paucity of inflammatory response in the face of mycobacterial dissemination that characterizes active TB with HIV co-infection.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Antigens, Bacterial / metabolism
  • CD4-Positive T-Lymphocytes / cytology
  • CD4-Positive T-Lymphocytes / microbiology*
  • Coinfection / microbiology
  • Coinfection / virology
  • Female
  • Gene Expression Regulation
  • HIV Infections / blood*
  • HIV Infections / complications
  • Humans
  • Immunophenotyping
  • Interferon-gamma / metabolism
  • Interleukin-2 / metabolism
  • Latent Tuberculosis / blood
  • Latent Tuberculosis / complications
  • Lymphocyte Subsets / microbiology
  • Male
  • Middle Aged
  • Mycobacterium tuberculosis*
  • Programmed Cell Death 1 Receptor / metabolism*
  • Tuberculosis / blood*
  • Tuberculosis / complications
  • Tumor Necrosis Factor-alpha / metabolism
  • Young Adult

Substances

  • Antigens, Bacterial
  • Interleukin-2
  • PDCD1 protein, human
  • Programmed Cell Death 1 Receptor
  • Tumor Necrosis Factor-alpha
  • Interferon-gamma