title: Waddlia chondrophila infects and multiplies in ovine trophoblast cells stimulating an inflammatory immune response.
abstract: BACKGROUND
  Waddlia chondrophila (W. chondrophila) is an emerging abortifacient organism which has been identified in the placentae of humans and cattle. The organism is a member of the order Chlamydiales, and shares many similarities at the genome level and in growth studies with other well-characterised zoonotic chlamydial abortifacients, such as Chlamydia abortus (C. abortus). This study investigates the growth of the organism and its effects upon pro-inflammatory cytokine expression in a ruminant placental cell line which we have previously utilised in a model of C. abortus pathogenicity.
  
  
  RESULTS
  Using qPCR, fluorescent immunocytochemistry and electron microscopy, we characterised the infection and growth of W. chondrophila within the ovine trophoblast AH-1 cell line. Inclusions were visible from 6 h post-infection (p.i.) and exponential growth of the organism could be observed over a 60 h time-course, with significant levels of host cell lysis being observed only after 36 h p.i. Expression of CXCL8, TNF-α, IL-1α and IL-1β were determined 24 h p.i. A statistically significant response in the expression of CXCL8, TNF-α and IL-1β could be observed following active infection with W. chondrophila. However a significant increase in IL-1β expression was also observed following the exposure of cells to UV-killed organisms, indicating the stimulation of multiple innate recognition pathways.
  
  
  CONCLUSIONS
  W. chondrophila infects and grows in the ruminant trophoblast AH-1 cell line exhibiting a complete chlamydial replicative cycle. Infection of the trophoblasts resulted in the expression of pro-inflammatory cytokines in a dose-dependent manner similar to that observed with C. abortus in previous studies, suggesting similarities in the pathogenesis of infection between the two organisms.
authors.affiliation: Moredun Research Institute, Edinburgh, Midlothian, United Kingdom.
authors.forename: Nick
authors.initials: N
authors.lastname: Wheelhouse
authors.affiliation: School of Life, Sport and Social Sciences, Edinburgh Napier University, Sighthill Campus, Edinburgh, United Kingdom.
authors.forename: Christopher
authors.initials: C
authors.lastname: Coyle
authors.affiliation: School of Life, Sport and Social Sciences, Edinburgh Napier University, Sighthill Campus, Edinburgh, United Kingdom.
authors.forename: Peter G
authors.initials: PG
authors.lastname: Barlow
authors.affiliation: Institute of Molecular Plant Sciences, University of Edinburgh, Edinburgh, United Kingdom.
authors.forename: Stephen
authors.initials: S
authors.lastname: Mitchell
authors.affiliation: Center for Research on Intracellular Bacteria (CRIB), Institute of Microbiology, University Hospital Center and University of Lausanne, Lausanne, Switzerland.
authors.forename: Gilbert
authors.initials: G
authors.lastname: Greub
authors.affiliation: Washington Animal Disease Diagnostic Laboratory, College of Veterinary Medicine, Washington State University, Pullman, Washington, United States of America.
authors.forename: Tim
authors.initials: T
authors.lastname: Baszler
authors.affiliation: School of Life, Sport and Social Sciences, Edinburgh Napier University, Sighthill Campus, Edinburgh, United Kingdom.
authors.forename: Mick T
authors.initials: MT
authors.lastname: Rae
authors.affiliation: Moredun Research Institute, Edinburgh, Midlothian, United Kingdom.
authors.forename: David
authors.initials: D
authors.lastname: Longbottom
mesh_terms: D000818:Animals; D002417:Cattle; D002689:Chlamydia / Q000235:genetics / Q000472:pathogenicity*; D005260:Female; D015870:Gene Expression; D053583:Interleukin-1beta / Q000096:biosynthesis; D016209:Interleukin-8 / Q000096:biosynthesis; D008854:Microscopy, Electron; D010920:Placenta / Q000382:microbiology* / Q000473:pathology; D011247:Pregnancy; D012756:Sheep / Q000382:microbiology; D034561:Sheep, Domestic / Q000382:microbiology; D014327:Trophoblasts / Q000378:metabolism / Q000382:microbiology*; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis
chemical_list: D053583:Interleukin-1beta; D016209:Interleukin-8; D014409:Tumor Necrosis Factor-alpha