title: Host-pathogen interplay at primary infection sites in pigs challenged with Actinobacillus pleuropneumoniae.
abstract: BACKGROUND
  Actinobacillus (A.) pleuropneumoniae is the causative agent of porcine pleuropneumonia and causes significant losses in the pig industry worldwide. Early host immune response is crucial for further progression of the disease. A. pleuropneumoniae is either rapidly eliminated by the immune system or switches to a long-term persistent form. To gain insight into the host-pathogen interaction during the early stages of infection, pigs were inoculated intratracheally with A. pleuropneumoniae serotype 2 and humanely euthanized eight hours after infection. Gene expression studies of inflammatory cytokines and the acute phase proteins haptoglobin, serum amyloid A and C-reactive protein were carried out by RT-qPCR from the lung, liver, tonsils and salivary gland. In addition, the concentration of cytokines and acute phase proteins were measured by quantitative immunoassays in bronchoalveolar lavage fluid, serum and saliva. In parallel to the analyses of host response, the impact of the host on the bacterial pathogen was assessed on a metabolic level. For the latter, Fourier-Transform Infrared (FTIR-) spectroscopy was employed.
  
  
  RESULTS
  Significant cytokine and acute phase protein gene expression was detected in the lung and the salivary gland however this was not observed in the tonsils. In parallel to the analyses of host response, the impact of the host on the bacterial pathogen was assessed on a metabolic level. For the latter investigations, Fourier-Transform Infrared (FTIR-) spectroscopy was employed. The bacteria isolated from the upper and lower respiratory tract showed distinct IR spectral patterns reflecting the organ-specific acute phase response of the host.
  
  
  CONCLUSIONS
  In summary, this study implies a metabolic adaptation of A. pleuropneumoniae to the porcine upper respiratory tract already during early infection, which might indicate a first step towards the persistence of A. pleuropneumoniae. Not only in lung, but also in the salivary gland an increased inflammatory gene expression was detectable during the acute stage of infection.
authors.affiliation: University Clinic for Swine, Department of Farm Animals and Veterinary Public Health, University of Veterinary Medicine Vienna, Vienna, Austria.
authors.forename: Elena L
authors.initials: EL
authors.lastname: Sassu
authors.affiliation: Department of Pathobiology, Functional Microbiology, Institute of Microbiology, University of Veterinary Medicine Vienna, Vienna, Austria.
authors.forename: Janna
authors.initials: J
authors.lastname: Frömbling
authors.affiliation: Department of Biomedical Sciences, Institute for Medical Biochemistry, University of Veterinary Medicine Vienna, Vienna, Austria.
authors.forename: J Catharina
authors.initials: JC
authors.lastname: Duvigneau
authors.affiliation: Department of Biomedical Sciences, Institute for Medical Biochemistry, University of Veterinary Medicine Vienna, Vienna, Austria.
authors.forename: Ingrid
authors.initials: I
authors.lastname: Miller
authors.affiliation: Department of Biomedical Sciences, Institute for Medical Biochemistry, University of Veterinary Medicine Vienna, Vienna, Austria.
authors.forename: Andrea
authors.initials: A
authors.lastname: Müllebner
authors.affiliation: Department of Animal Medicine and Surgery, University of Murcia, Murcia, Spain.
authors.forename: Ana M
authors.initials: AM
authors.lastname: Gutiérrez
authors.affiliation: Department of Pathobiology, Functional Microbiology, Institute of Microbiology, University of Veterinary Medicine Vienna, Vienna, Austria.
authors.forename: Tom
authors.initials: T
authors.lastname: Grunert
authors.affiliation: Department of Pathobiology, Institute of Immunology, University of Veterinary Medicine Vienna, Vienna, Austria.
authors.forename: Martina
authors.initials: M
authors.lastname: Patzl
authors.affiliation: Department of Pathobiology, Institute of Immunology, University of Veterinary Medicine Vienna, Vienna, Austria.
authors.forename: Armin
authors.initials: A
authors.lastname: Saalmüller
authors.affiliation: Forensic Medicine and Ambulatory Services, Clinic for Swine and Small Ruminants, University of Veterinary Medicine Hannover, Hannover, Germany.
authors.forename: Alexandra
authors.initials: A
authors.lastname: von Altrock
authors.affiliation: Forensic Medicine and Ambulatory Services, Clinic for Swine and Small Ruminants, University of Veterinary Medicine Hannover, Hannover, Germany.
authors.forename: Anne
authors.initials: A
authors.lastname: Menzel
authors.affiliation: Forensic Medicine and Ambulatory Services, Clinic for Swine and Small Ruminants, University of Veterinary Medicine Hannover, Hannover, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Ganter
authors.affiliation: Department of Pathobiology, Functional Microbiology, Institute of Microbiology, University of Veterinary Medicine Vienna, Vienna, Austria.
authors.forename: Joachim
authors.initials: J
authors.lastname: Spergser
authors.affiliation: Department of Pathology, University of Veterinary Medicine Hannover, Hannover, Germany.
authors.forename: Marion
authors.initials: M
authors.lastname: Hewicker-Trautwein
authors.affiliation: Institute for Microbiology, University of Veterinary Medicine Hannover, Hannover, Germany.
authors.forename: Jutta
authors.initials: J
authors.lastname: Verspohl
authors.affiliation: Department of Pathobiology, Functional Microbiology, Institute of Microbiology, University of Veterinary Medicine Vienna, Vienna, Austria.
authors.forename: Monika
authors.initials: M
authors.lastname: Ehling-Schulz
authors.affiliation: University Clinic for Swine, Department of Farm Animals and Veterinary Public Health, University of Veterinary Medicine Vienna, Vienna, Austria. isabel.hennig-pauka@vetmeduni.ac.at.
authors.forename: Isabel
authors.initials: I
authors.lastname: Hennig-Pauka
mesh_terms: D000189:Actinobacillus Infections / Q000276:immunology / Q000378:metabolism / Q000382:microbiology / Q000662:veterinary*; D016977:Actinobacillus pleuropneumoniae / Q000276:immunology / Q000302:isolation & purification / Q000378:metabolism; D000818:Animals; D016207:Cytokines / Q000378:metabolism; D011001:Pleuropneumonia / Q000276:immunology / Q000378:metabolism / Q000382:microbiology / Q000662:veterinary*; D013552:Swine; D013553:Swine Diseases / Q000276:immunology / Q000378:metabolism / Q000382:microbiology*; D059467:Transcriptome
chemical_list: D016207:Cytokines
keywords: Acute phase proteins; Early immune response; FTIR; Gene expression; Salivary gland