Expression of secretory leukocyte protease inhibitor and elafin in human fallopian tube and in an in-vitro model of Chlamydia trachomatis infection

Secretory leukocyte protease inhibitor (SLPI) and elafin are anti-protease and anti-microbial molecules with a role in innate immune defence. They have been demonstrated at multiple mucosal surfaces including those of the female reproductive tract. This study details their expression in human Fallopian tubes (ampullary region) throughout the menstrual cycle (n = 18) and from women with ectopic pregnancy (n = 6), and examined their regulation by infection with Chlamydia trachomatis in an in-vitro model. Quantitative real-time PCR analysis showed that SLPI and elafin were constitutively expressed in the Fallopian tube during the menstrual cycle but were increased in ectopic pregnancy (P < 0.05 versus early-mid luteal phase, P < 0.01 versus all phases, respectively). SLPI and elafin were immunolocalised to the Fallopian tube epithelium in biopsies from non-pregnant women and those with ectopic pregnancy. An in-vitro culture model of C. trachomatis infection of the OE-E6/E7 oviductal epithelial cell line showed that elafin mRNA expression was upregulated in response to chlamydial infection. These data suggest that SLPI and elafin have a role in the innate immune defence of the Fallopian tube in infection and ectopic pregnancy. Their role is likely to include regulation of protease activity, wound healing and tissue remodelling.