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Updated: Jan 28, 2026

Detection of Neu1 Sialidase Activity in Regulating TOLL-like Receptor Activation
Published on: September 7, 2010
Toll-like receptors blocking restores in vitro microbicidal activity in latent tuberculosis-infected subjects
F D Coelho da Silva1, L P Covre1, L L Stringari1
1Cellular and Molecular Immunology Laboratory, Núcleo de Doenças Infecciosas (NDI), Universidade Federal do Espírito Santo (UFES), Vitória.
Background:
Latent tuberculous infection (LTBI) can function as a 'reservoir' for Mycobacterium tuberculosis. Given that T-regulatory cell (Treg) numbers are augmented in LTBI, it is likely that Toll-like receptors (TLRs) may have a role in Treg function. Elucidation of the immune mechanisms associated with tuberculosis (TB) development may help to control M. tuberculosis spread.OBJECTIVE: To investigate the role of TLR2, TLR4 and TLR9 in hindered in vitro microbicidal activity and increase Treg number during LTBI.
Design:
Whole blood cell cultures from individuals with LTBI and healthy controls (HCs) infected with live M. tuberculosis H37Rv strain were used to investigate the effect of TLR2, TLR4 and TLR9 on Treg number, microbicidal activity, and interferon-gamma and interleukin (IL)10 production.
Results:
LTBI subjects were characterised by increased Treg number and impaired microbicidal activity when compared with HCs. Specific blockade of TLR4 and TLR9 led to a significant reduction in Treg number, a decrease in IL-10 production and substantial upregulation of microbicidal activity.
Conclusion:
M. tuberculosis infection may activate TLR4 and TLR9 pathways to suppress M. tuberculosis-specific immune responses. Here, we show that activation of TLR4 and TLR9 hinder microbicidal activity during LTBI.
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