title: Permissiveness of bovine epithelial cells from lung, intestine, placenta and udder for infection with Coxiella burnetii.
abstract: Ruminants are the main source of human infections with the obligate intracellular bacterium Coxiella (C.) burnetii. Infected animals shed high numbers of C. burnetii by milk, feces, and birth products. In goats, shedding by the latter route coincides with C. burnetii replication in epithelial (trophoblast) cells of the placenta, which led us to hypothesize that epithelial cells are generally implicated in replication and shedding of C. burnetii. We therefore aimed at analyzing the interactions of C. burnetii with epithelial cells of the bovine host (1) at the entry site (lung epithelium) which govern host immune responses and (2) in epithelial cells of gut, udder and placenta decisive for the quantity of pathogen excretion. Epithelial cell lines [PS (udder), FKD-R 971 (small intestine), BCEC (maternal placenta), F3 (fetal placenta), BEL-26 (lung)] were inoculated with C. burnetii strains Nine Mile I (NMI) and NMII at different cultivation conditions. The cell lines exhibited different permissiveness for C. burnetii. While maintaining cell viability, udder cells allowed the highest replication rates with formation of large cell-filling Coxiella containing vacuoles. Intestinal cells showed an enhanced susceptibility to invasion but supported C. burnetii replication only at intermediate levels. Lung and placental cells also internalized the bacteria but in strikingly smaller numbers. In any of the epithelial cells, both Coxiella strains failed to trigger a substantial IL-1β, IL-6 and TNF-α response. Epithelial cells, with mammary epithelial cells in particular, may therefore serve as a niche for C. burnetii replication in vivo without alerting the host's immune response.
authors.affiliation: Institute of Molecular Pathogenesis, Friedrich-Loeffler-Institut (FLI), Naumburger Strasse 96a, 07743, Jena, Germany.
authors.forename: Katharina
authors.initials: K
authors.lastname: Sobotta
authors.affiliation: Institute of Molecular Pathogenesis, Friedrich-Loeffler-Institut (FLI), Naumburger Strasse 96a, 07743, Jena, Germany.
authors.forename: Katharina
authors.initials: K
authors.lastname: Bonkowski
authors.affiliation: Institute of Molecular Pathogenesis, Friedrich-Loeffler-Institut (FLI), Naumburger Strasse 96a, 07743, Jena, Germany.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Liebler-Tenorio
authors.affiliation: ISP, INRA, Université Tours, UMR 1282, 37380, Nouzilly, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Germon
authors.affiliation: ISP, INRA, Université Tours, UMR 1282, 37380, Nouzilly, France.
authors.forename: Pascal
authors.initials: P
authors.lastname: Rainard
authors.affiliation: Department of Anatomy, University of Veterinary Medicine Hannover, Bischofsholer Damm 15, 30173, Hannover, Germany.
authors.forename: Nina
authors.initials: N
authors.lastname: Hambruch
authors.affiliation: Department of Anatomy, University of Veterinary Medicine Hannover, Bischofsholer Damm 15, 30173, Hannover, Germany.
authors.forename: Christiane
authors.initials: C
authors.lastname: Pfarrer
authors.affiliation: Research Group Microbial Immunology, Leibniz Institute for Natural Product Research and Infection Biology/Hans Knoell Institute, Beutenbergstrasse 11a, 07745, Jena, Germany.
authors.forename: Ilse D
authors.initials: ID
authors.lastname: Jacobsen
authors.affiliation: Institute of Molecular Pathogenesis, Friedrich-Loeffler-Institut (FLI), Naumburger Strasse 96a, 07743, Jena, Germany. christian.menge@fli.de.
authors.forename: Christian
authors.initials: C
authors.lastname: Menge
mesh_terms: D000818:Animals; D057138:Bacterial Shedding; D002417:Cattle / Q000382:microbiology; D002418:Cattle Diseases / Q000382:microbiology*; D002460:Cell Line; D016997:Coxiella burnetii / Q000502:physiology*; D016207:Cytokines / Q000502:physiology; D004847:Epithelial Cells / Q000382:microbiology*; D005260:Female; D005434:Flow Cytometry / Q000662:veterinary; D054884:Host-Pathogen Interactions / Q000502:physiology; D007413:Intestinal Mucosa / Q000382:microbiology*; D008168:Lung / Q000382:microbiology*; D008321:Mammary Glands, Animal / Q000382:microbiology*; D008856:Microscopy, Fluorescence / Q000662:veterinary; D010920:Placenta / Q000382:microbiology*; D011247:Pregnancy; D011778:Q Fever / Q000382:microbiology / Q000662:veterinary*; D060888:Real-Time Polymerase Chain Reaction / Q000662:veterinary
chemical_list: D016207:Cytokines