Toll-like receptor 2 in host defense against Mycobacterium tuberculosis: to be or not to be-that is the question

Curr Opin Immunol. 2016 Oct;42:76-82. doi: 10.1016/j.coi.2016.06.003. Epub 2016 Jun 18.


Toll-like receptor (TLR) 2 is expressed on immune cells and respiratory epithelial cells lining the lung. TLR2 is not critical for protection during acute Mycobacterium tuberculosis (Mtb) infection but it has a significant multi-faceted role in containing chronic infection. This review highlights the contribution of TLR2 to host protection, immune evasion by Mtb and immune regulation during chronic Mtb infection. The TLR2-triggered pro-inflammatory cytokines initiate protective mechanisms and limit Mtb replication while the immune evasion pathways counterattack anti-bacterial effector mechanisms. The immune regulation pathways that are activated dampen TLR2 signaling. The combinatorial effect of these functional responses is persistence of Mtb with minimal immunopathology.

Publication types

  • Review
  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Humans
  • Immune Evasion
  • Immunity, Innate*
  • Inflammation
  • Macrophages / immunology*
  • Macrophages / microbiology
  • Mycobacterium tuberculosis / immunology*
  • Signal Transduction
  • Toll-Like Receptor 2 / immunology
  • Toll-Like Receptor 2 / metabolism*
  • Tuberculosis / immunology*


  • Toll-Like Receptor 2