Microbial compounds induce the expression of pro-inflammatory cytokines, chemokines and human β-defensin-2 in vaginal epithelial cells

Vaginal epithelium has a powerful innate immune system that protects the female reproductive organs from bacteria] and fungal infections. In the present study, we aimed to explore whether the Toll-like receptor (TLR) signaling pathway and the induction of pro-inflammatory cytokines and antimicrobial peptides could contribute to the protection against pathogenic microorganisms in vaginal epithelia, using an immortalized vaginal epithelial cell line PK E6/E7 as a model. We found that TLR2 and TLR4 receptors are expressed in vivo in the vaginal epithelia and in vitro in PK E6/E7 vaginal epithelial cell line. The Gram-negative cell wall compound lipopolysaccharide (LPS), the Gram-positive compound peptidoglycan (PGN), heat-killed Candida albicans and zymosan significantly (P < 0.05) induced the expression of pro-inflammatory cytokines and chemokines such as TNF-alpha and IL-8/CXCL8 in vaginal epithelial cells. Furthermore, the expression and production of human beta-defensin-2 (hBD2), an antimicrobial peptide with chemotactic functions, was also up-regulated in PK E6/E7 cells after treatment with LPS, PGN or e. albicans. Treatment of vaginal epithelial cells with microbial compounds induced the activation and nuclear translocation of NF-kappa B transcription factor, a key element of innate and adaptive immune responses. In our work, we provide evidence that microbial compounds induce the production of pro-inflammatory cytokines, chemokines and antimicrobial peptides in vaginal epithelia] cells. In vivo, vaginal epithelial cell-derived inflammatory mediators and antimicrobial peptides may play important roles in vaginal immune responses and in the elimination of pathogens from the female reproductive tract. (C) 2005 Elsevier SAS. All rights reserved.