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Published on: December 8, 2011
Polyanionic microbicides modify Toll-like receptor-mediated cervicovaginal immune responses.
R T Trifonova1, G F Doncel, R N Fichorova
1Department of Obstetrics, Brigham and Women's Hospital, Laboratory of Genital Tract Biology, Boston, MA 02115, USA. rfichorova@rics.bwh.harvard.edu
Antimicrobial Agents and Chemotherapy
|January 14, 2009
Summary
Polyanionic microbicides may hinder the vaginal epithelium's ability to fight infections by interfering with Toll-like receptor (TLR) signaling. This interference impacts cytokine production, potentially affecting HIV-1 transmission risk.
Area of Science:
- Immunology
- Infectious Diseases
- Vaginal Epithelial Biology
Background:
- Topical microbicides aim to prevent HIV-1 transmission by avoiding inflammation and preserving innate immune responses.
- Vaginal epithelial cells utilize Toll-like receptor (TLR)-mediated pathways for pathogen defense.
- Efficacy of microbicides depends on their compatibility with the vaginal immune system.
Purpose of the Study:
- To investigate the impact of polyanionic microbicide compounds on human cervical and vaginal epithelial cell responses to TLR ligands.
- To assess whether microbicides modulate innate immune signaling pathways crucial for host defense.
Main Methods:
- Human cervical and vaginal epithelial cells were exposed to polyanionic compounds (dextran sulfate, polystyrene sulfonate) and synthetic TLR ligands (Pam(3)CSK(4), MALP-2, poly(I:C)).
- Cell activation was measured via NF-kappaB reporter gene transactivation and cytokine production (mRNA and protein levels).
- Effects of sulfate/sulfonate moieties were evaluated using an unsulfated dextran control.
Main Results:
- Polyanionic compounds enhanced TLR-triggered NF-kappaB activation but significantly inhibited TLR-mediated cytokine production.
- Decreased levels of proinflammatory (IL-8, IL-1beta) and antiviral (beta interferon) cytokines were observed.
- These inhibitory effects were attributed to the sulfate/sulfonate groups, as the unsulfated control had no impact.
Conclusions:
- The studied microbicide compounds can selectively interfere with TLR-mediated epithelial immune responses.
- This interference occurs at multiple points within the TLR signaling pathways.
- Further research is crucial to understand the implications of this immune modulation on HIV-1 transmission risk.
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