Toll-like receptor-mediated innate immune responses by recognition of the recombinant dormancy-associated Mycobacterium tuberculosis proteins Rv2659c and Rv1738

PLoS One. 2022 Sep 1;17(9):e0273517. doi: 10.1371/journal.pone.0273517. eCollection 2022.

Abstract

Tuberculosis (TB) caused by Mycobacterium tuberculosis (Mtb) poses a major threat to the global public health. Importantly, latent tuberculosis infection (LTBI) still impedes the elimination of TB incidence since it has a substantial risk to develop active disease. A multi-stage subunit vaccine comprising active and latency antigens of Mtb has been raised as the promising vaccine to trigger immune protection against all stages of TB. Therefore, the discovery of new antigens that could trigger broad immune response is essential. While current development of TB vaccine mainly focuses on protective immunity mediated by adaptive immune response, the knowledge on triggering the innate immune response by antigens is still limited. We showed that recombinant dormancy-associated Mtb proteins Rv2659c and Rv1738 were recognized by human innate immune recognition molecules, Toll-like receptors (TLRs) 2 and 4 by using HEK-Blue™ hTLR2/hTLR4 systems. We further demonstrated that these two proteins activated phosphorylated NF-κB p65 (Ser536) in the human CD14+ blood cells. We also investigated that these two proteins significantly induced level of pro- and anti-inflammatory cytokines (IL-1β, IL-6, IL-8, IL-10 and TNF-α) which were mediated through TLR2 and TLR4 pathways in human peripheral blood mononuclear cells (hPBMCs). These findings suggest that proteins Rv2659c and Rv1738 stimulated innate immune response targeting TLR2 and TLR4 to produce inflammatory cytokines, and their benefits would be valuable for the development of an effective prophylactic tuberculosis vaccine.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins* / genetics
  • Bacterial Proteins* / immunology
  • Cytokines / metabolism
  • Humans
  • Immunity, Innate* / genetics
  • Leukocytes, Mononuclear / metabolism
  • Mycobacterium tuberculosis* / immunology
  • Recombinant Proteins / genetics
  • Toll-Like Receptor 2 / metabolism
  • Toll-Like Receptor 4 / genetics
  • Toll-Like Receptors* / genetics
  • Tuberculosis Vaccines
  • Tuberculosis* / genetics

Substances

  • Bacterial Proteins
  • Cytokines
  • Recombinant Proteins
  • Rv1738 protein, Mycobacterium tuberculosis
  • Toll-Like Receptor 2
  • Toll-Like Receptor 4
  • Toll-Like Receptors
  • Tuberculosis Vaccines
  • Rv2659c protein, Mycobacterium tuberculosis

Grants and funding

This work was supported by Mahidol University (Basic research fund:Fiscal year 2022) and the Graduate Scholarship Program of the Faculty of Medical Technology, Mahidol University. The funders had no role in study design, manuscript preparation nor publication decisions.