Journal of Reproductive Immunology 80 (2009) 49–56 Ovine trophoblast is a primary source of TNF during Chlamydophila abortus infection Nick Wheelhouse a,∗ , Sean Wattegedera a , James Stanton b , Stephen Maley a , Donna Watson a , Catherine Jepson a , David Deane a , David Buxton a , David Longbottom a , Tim Baszler b,c , Gary Entrican a a Moredun Research Institute, Pentlands Science Park, Bush Loan, Midlothian, Edinburgh, EH26 0PZ, UK b Washington Animal Disease Diagnostic Laboratory, Washington State University, Pullman, WA 99164-7034, USA c The Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, WA 99164-7034, USA Received 2 October 2008; received in revised form 10 December 2008; accepted 11 December 2008 Abstract Chlamydophila abortus is a Gram-negative obligate intracellular bacterium that causes infectious abortion in sheep (ovine enzootic abortion, OEA) and humans. Infected placentas recovered from sheep that experience OEA have thickened membranes, contain dense inflammatory cellular infiltrates and show evidence of intravascular thrombosis. Despite widespread inflammation, chlamydial multiplication is restricted to the chorionic trophoblast cells. To investigate the potential role of trophoblast in the initiation and propagation of placental inflammation during OEA, the AH-1 ovine trophoblast cell line was experimentally infected with C. abortus and analysed for the release of pro-inflammatory mediators. C. abortus was found to induce the release of both tumour necrosis factor- (TNF) and CXCL8 (interleukin-8) from AH-1 cells in a dose- and time-dependent manner. Ultra-violet (UV)-killed organisms did not elicit this profile, indicating that intracellular multiplication of C. abortus was required for release of these pro-inflammatory mediators. Exposure of AH-1 cells to recombinant ovine TNF alone resulted in the release of CXCL8, suggestive of a self-propagating inflammatory cytokine and chemokine cascade. These data indicate a primary role for trophoblast in the initiation and propagation of placental inflammation during chlamydial abortion. © 2009 Elsevier Ireland Ltd. All rights reserved. Keywords: Trophoblast; Chlamydophila abortus; TNF; CXCL8; Infectious abortion 1. Introduction Chlamydophila abortus is an obligate intracellular bacterium that causes ovine enzootic abortion (OEA) in sheep and that also presents a serious health risk ∗ Corresponding author. Tel.: +44 131 445 5111; fax: +44 131 445 6235. E-mail address: nick.wheelhouse@moredun.ac.uk (N. Wheelhouse). to pregnant women (Entrican et al., 2001). There is often little warning of OEA in sheep flocks, with abortion typically occurring in the final 2–3 weeks of gestation (Longbottom and Coulter, 2003). Follow- ing abortion, placental membranes appear reddened and thickened with intense inflammatory cell infiltrates. This is accompanied by destruction of the trophoblast layer (chorionic epithelium) which is the site of C. abortus multiplication in the placenta (Buxton et al., 2002). 0165-0378/$ – see front matter © 2009 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.jri.2008.12.003