Innate immune mediator profiles and their regulation in a novel polarized immortalized epithelial cell model derived from human endocervix

Abstract

The endocervix in the female reproductive tract (FRT) is susceptible to sexually transmitted pathogens such as Chlamydia trachomatis and Neisseria gonorrhoeae. Endocervical epithelial cells in vivo make innate immune mediators that likely aid in the protection from these pathogens. In vitro studies to investigate the innate epithelial cell immune response to endocervical pathogens have been hindered by the paucity of human endocervix-derived epithelial cell lines that display the differentiation proteins and functional characteristics of their site of origin. We have established an immortalized epithelial cell line (A2EN) derived from an endocervical tissue explant that can be polarized to exhibit distinct apical and basolateral membrane domains. Polarized A2EN cells secrete mucus at their apical surface, and express MUC5B, a mucin specific to the endocervix. Polarized A2EN cells also express hormone receptors that respond appropriately to female steroid hormones. Polarized A2EN cells can be stimulated with the toll-like receptor 3 agonist, polyI:C, to express anti-microbial peptides (AMPs) as well as pro-inflammatory cytokines and chemokines. Cytokines and chemokines are also differentially secreted depending on the hormone milieu in which the cells are exposed. We conclude that polarized A2EN cells maintain distinctive phenotypic and functional characteristics of the epithelial cells found in the endocervix and, hence, could provide a useful, new in vitro model system for investigations on the role of endogenous and exogenous factors that regulate endocervical epithelial cell immunity including studies on sexually transmitted infections and topical microbicides.