ABSTRACT

Background: Toll-like receptors (TLR) contribute to initial immune response to pathogens, however, their precise role in human alveolar macrophages response towards Mycobacterium tuberculosis (M. tuberculosis) remains poorly characterized. The aim of this study was to investigate this process in the alveolar and systemic compartments.
Methods: TLR2 and TLR9 expression was determined in monocytes and alveolar macrophages stimulated with mycobacterial lipoarabinomannan and DNA or infected with the virulent strain of M. tuberculosis by flowcytometry. Ligand-specific and infection-induced production of proinflammatory cytokines was assessed by ELISA.
Results: M. tuberculosis infection as well as stimulation with M. tuberculosis antigens modulated TLR2 but not TLR9 expression in monocytes and induced specific TNF-<6#945 and IL6 release. Alveolar macrophages did not modulated TLR2 nor TLR9 expression.
Conclusions: Expression and function of TLR2 and TLR9 after exposure to M. tuberculosis is different between alveolar and systemic phagocytes. TLRs role in pulmonary defense may be relevant in the generation of immediate response as well as in control of M. tuberculosis infection.

KEYWORDS

TLR, alveolar macrophages, Mycobacterium tuberculosis.

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