Chlamydial infection of polarized HeLa cells induces PMN chemotaxis but the cytokine profile varies between disseminating and non-disseminating strains

While genital infections caused by Chlamydia trachomatis are generally asym ptomatic, the density and pattern of inflammation varies considerably. The purpose of this study was to try to dissect the signalling in chlamydiae-in fected epithelial cells that triggers innate responses and regulates polymo rphonuclear neutrophil (PMN) chemotaxis. Polarized endocervical epithelial HeLa cells, grown in commercial inserts, were inoculated either with the no n-disseminating (luminal) serovar E or the disseminating serovar L2. At 12- 48 h after infection, the chambers were used in a quantitative chemotaxis a ssay, and cytokine production by infected cells was examined using cDNA mic roarray technology and confirmed by enzyme-linked immunosorbent assay (ELIS A). Infection of HeLa cells with C. trachomatis E or L2 induced a strong an d similar PMN chemotactic response, but larger amounts of interleukin (IL)- 8 and IL-11 were released after infection with serovar L2. IL-6 was also pr oduced in modest amounts after infection with either strain, but no IL-1 al pha or tumour necrosis factor (TNF)-alpha was detected in any of the cultur e supernatants tested. IL-11 did not appear to influence the PMN response t o chlamydial infection, but secretion of large amounts of this anti-inflamm atory cytokine, mainly active on macrophages, in the very early stages of t he infection may allow C trachomatis to escape some innate defences to esta blish infection.