Secretion of cytokines and chemokines by polarized human epithelial cells from the female reproductive tract

BACKGROUND: Pro-inflammatory chemokines that attract and cytokines that activate immune cells contribute to normal physiological homeostasis in the female reproductive tract, and are needed to deal effectively with potential pathogenic microbes. Mucosal epithelial cells are capable of producing these factors that communicate with cells of the innate and adaptive immune systems. METHODS: Epithelial cells from Fallopian tube, endometrium and endocervix were isolated and grown to high transepithelial resistance in cell inserts from seven patients who had hysterectomies. Interleukin (IL)-8, IL-6, granulocyte colony-stimulating factor (G-CSF), monocyte chemoattractant protein-1 (MCP-1), granulocyte-macrophage colony-stimulating factor (GM-CSF), tumour necrosis factor-alpha (TNF-alpha) and macrophage inflammatory peptide-1 beta (MIP-1 beta) were assessed by Luminex bead analysis or enzyme-linked immunosorbent assay (ELISA) in epithelial cell conditioned media from the apical and basolateral compartments. RESULTS: With the exception of MCP-1, the seven chemokines/cytokines constitutively produced by the polarized epithelial cells were preferentially secreted apically. A concentration pattern was found in all cases, with IL-8 and IL-6 produced in the greatest quantity. CONCLUSIONS: The concentrations of IL-8, IL-6, G-CSF and MCP-1 are similar to the levels found in reproductive tract fluids of patients with infection. The constitutive secretion and compartmentalization of large quantities of bioactive chemokines and cytokines provide additional evidence for the role of epithelial cells as gatekeepers of innate immune protection in the female reproductive tract.