Modulatory effect of Tim-3/Galectin-9 axis on T-cell-mediated immunity in pulmonary tuberculosis

J Biosci. 2020:45:60.

Abstract

Patients affected by pulmonary tuberculosis (PTB) manifest deficiencies in innate cellular immunity. The Tim3/Galectin-9 axis is an important regulator of Th1 cell immunity, leading to Th1 cell apoptosis. Herein, this study aims to clarify the underlying roles of the Tim-3/Galectin-9 axis in T-cell immunity in PTB. Peripheral blood mononuclear cells (PBMCs) were extracted from subjects with and without PTB to examine the expression of CD4, CD8, CD25, and Tim-3 under the stimulation of Mycobacterium tuberculosis (MTB) and purified protein derivative (PPD). In addition, the expression of Tim-3 and Galectin-9 in PBMCs was determined. The Tim-3/Galectin-9 axis in the PBMCs was activated or blocked to detect the secreted levels of IFN-γ, TNF-α, IL-2, and IL-22. MTB stimulation increased the expression of CD4, CD8, CD25, Tim-3, and Galectin-9 in PBMCs. The blockade of Tim-3/Galectin-9 axis resulted in reduced secretion of IFN-γ, TNF-α, IL-2, and IL-22 from T-cells. Moreover, Tim-3+CD4+T, Tim-3+CD8+, and Tim-3+CD25+T cells exhibited a greater ability to inhibit the replication of MTB in macrophages. Taken conjointly, the blockade of Tim-3/ Galectin-9 axis inhibits the secretion of inflammatory cytokines in T-cells to regulate the T-cell immunity in PTB.

MeSH terms

  • Adult
  • Cytokines / metabolism
  • Female
  • Galectins / metabolism*
  • Gene Expression Regulation / immunology
  • Hepatitis A Virus Cellular Receptor 2 / metabolism*
  • Humans
  • Immunity, Cellular
  • Leukocytes, Mononuclear / immunology
  • Lymphocyte Activation / immunology
  • Macrophages / immunology
  • Macrophages / metabolism
  • Male
  • Middle Aged
  • Mycobacterium tuberculosis / physiology
  • T-Lymphocytes, Regulatory / immunology
  • Th1 Cells / immunology*
  • Th1 Cells / metabolism
  • Tuberculosis, Pulmonary / genetics
  • Tuberculosis, Pulmonary / immunology*

Substances

  • Cytokines
  • Galectins
  • HAVCR2 protein, human
  • Hepatitis A Virus Cellular Receptor 2
  • LGALS9 protein, human