title: Host-pathogen interactions in specific pathogen-free chickens following aerogenous infection with Chlamydia psittaci and Chlamydia abortus.
abstract: Although Chlamydia (C.) psittaci infections are recognized as an important factor causing economic losses and impairing animal welfare in poultry production, the specific mechanisms leading to severe clinical outcomes are poorly understood. In the present study, we comparatively investigated pathology and host immune response, as well as systemic dissemination and expression of essential chlamydial genes in the course of experimental aerogeneous infection with C. psittaci and the closely related C. abortus, respectively, in specific pathogen-free chicks. Clinical signs appeared sooner and were more severe in the C. psittaci-infected group. Compared to C. abortus infection, more intense systemic dissemination of C. psittaci correlated with higher and faster infiltration of immune cells, as well as more macroscopic lesions and epithelial pathology, such as hyperplasia and erosion. In thoracic air sac tissue, mRNA expression of immunologically relevant factors, such as IFN-γ, IL-1β, IL-6, IL-17, IL-22, LITAF and iNOS was significantly stronger up-regulated in C. psittaci- than in C. abortus-infected birds between 3 and 14 days post-infection. Likewise, transcription rates of the chlamydial genes groEL, cpaf and ftsW were consistently higher in C. psittaci during the acute phase. These findings illustrate that the stronger replication of C. psittaci in its natural host also evoked a more intense immune response than in the case of C. abortus infection.
authors: Department of Molecular Biotechnology and Immunology, Ghent University, Belgium.
authors: Isabelle
authors: I
authors: Kalmar
authors: Institute of Molecular Pathogenesis, Friedrich-Loeffler-Institut (Federal Research Institute for Animal Health), Jena, Germany.
authors: Angela
authors: A
authors: Berndt
authors: Department of Molecular Biotechnology and Immunology, Ghent University, Belgium.
authors: Lizi
authors: L
authors: Yin
authors: Department of Pathology, Bacteriology and Avian Diseases, Ghent University, Belgium.
authors: Koen
authors: K
authors: Chiers
authors: Institute of Molecular Pathogenesis, Friedrich-Loeffler-Institut (Federal Research Institute for Animal Health), Jena, Germany. Electronic address: konrad.sachse@fli.bund.de.
authors: Konrad
authors: K
authors: Sachse
authors: Department of Molecular Biotechnology and Immunology, Ghent University, Belgium.
authors: Daisy
authors: D
authors: Vanrompay
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D002645:Chickens / Q000276:immunology* / Q000382:microbiology*; D002689:Chlamydia / Q000235:genetics / Q000276:immunology / Q000472:pathogenicity; D002690:Chlamydia Infections / Q000276:immunology / Q000473:pathology / Q000662:veterinary*; D002691:Chlamydophila psittaci / Q000235:genetics / Q000276:immunology / Q000472:pathogenicity; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D054884:Host-Pathogen Interactions / Q000235:genetics / Q000276:immunology; D008213:Lymphocyte Activation; D011201:Poultry Diseases / Q000276:immunology* / Q000473:pathology; D009956:Psittacosis / Q000276:immunology / Q000473:pathology / Q000662:veterinary*; D012137:Respiratory System / Q000276:immunology / Q000382:microbiology / Q000473:pathology; D013047:Specific Pathogen-Free Organisms
keywords: Avian chlamydiosis; Chlamydia abortus; Chlamydia psittaci; Experimental infection; Host immune response; Pathogenesis