Immune activation and regulatory T cells in Mycobacterium tuberculosis infected lymph nodes

BMC Immunol. 2018 Nov 8;19(1):33. doi: 10.1186/s12865-018-0266-8.

Abstract

Background: Lymph node tuberculosis (LNTB) is the most frequent extrapulmonary form of tuberculosis (TB). Studies of human tuberculosis at sites of disease are limited. LNTB provides a unique opportunity to compare local in situ and peripheral blood immune response in active Mycobacterium tuberculosis (Mtb) disease. The present study analysed T regulatory cells (Treg) frequency and activation along with CD4+ T cell function in lymph nodes from LNTB patients.

Results: Lymph node mononuclear cells (LNMC) were compared to autologous peripheral blood mononuclear cells (PBMC). LNMC were enriched for CD4+ T cells with a late differentiated effector memory phenotype. No differences were noted in the frequency and mutifunctional profile of memory CD4+ T cells specific for Mtb. The proportion of activated CD4+ and Tregs in LNMC was increased compared to PBMC. The correlation between Tregs and activated CD4+ T cells was stronger in LNMC than PBMC. Tregs in LNMC showed a strong positive correlation with Th1 cytokine production (IL2, IFNγ and TNFα) as well as MIP-1α after Mtb antigen stimulation. A subset of Tregs in LNMC co-expressed HLA-DR and CD38, markers of activation.

Conclusion: Further research will determine the functional relationship between Treg and activated CD4+ T cells at lymph node sites of Mtb infection.

Keywords: Lymph node; Lymphadenitis; Treg cells; Tuberculosis; activation; conventional T cell.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adolescent
  • Adult
  • Female
  • Humans
  • Leukocytes, Mononuclear / cytology
  • Leukocytes, Mononuclear / immunology*
  • Lymph Nodes / microbiology*
  • Lymphocyte Activation / immunology
  • Male
  • Middle Aged
  • Mycobacterium tuberculosis / immunology*
  • T-Lymphocytes, Regulatory / cytology
  • T-Lymphocytes, Regulatory / immunology*
  • Tuberculosis, Lymph Node / immunology*