title: Detection of PR-39, a porcine host defence peptide, in different cell sub-linages in pigs infected with Actinobacillus pleuropneumoniae.
abstract: Innate immunity is critically important for the outcome of infection in many diseases. It was previously shown that cathelicidin PR-39, an important porcine multifunctional host defence peptide, is elevated in bronchoalveolar lavage fluid and respiratory tract tissue after experimental infection with Actinobacillus pleuropneumoniae (A.pp.). To date, neutrophil polymorphonuclear leukocytes (PMNs) are thought to be the only source of PR-39. The aim of this study was to further characterize PR-39⁺ cells and selected immune cell populations in lung tissue during the peracute (7-10 hours), acute (2 days), reconvalescent (7 days) and chronic (21 days) stages of experimental infection with A.pp. serotype 2. In total, six mock-infected control pigs and 12 infected pigs were examined. Using immunofluorescence double-labeling, antibodies against PR-39 were combined with antibodies against CD3 (T-cells), CD79 (B-cells), Iba1 (activated macrophages), TTF-1 (lung epithelial cells expressing surfactant proteins), macrophage/L1 protein and myeloperoxidase (MPO, cells of the myeloid linage). In the peracute and acute phases of infection, total PR-39⁺ cells and myeloid linage cells increased, whereas CD3⁺ cells and TTF-1⁺ cells decreased. Double labeling revealed that most Macrophage/L1 protein+ cells and to a lesser extent MPO⁺ cells co-expressed PR-39. In addition, few bronchial epithelial cells and type 2 alveolar epithelial cells (both identified with TTF-1) produced PR-39. Occasionally, CD3⁺ T cells expressing PR-39 were seen in infected animals. Taken together, this study identifies cell types, other than PMNs, in lungs of A.pp.-infected pigs that are capable of producing PR-39. In addition, these findings provide further insights into the dynamics of different immune cell populations during A.pp.-infection.
authors.affiliation: Institute of Anatomy, Histology and Embryology, Department of Pathobiology, University of Veterinary Medicine Vienna, Vienna, Austria.
authors.forename: S
authors.initials: S
authors.lastname: Gabner
authors.affiliation: Institute of Anatomy, Histology and Embryology, Department of Pathobiology, University of Veterinary Medicine Vienna, Vienna, Austria.
authors.forename: M
authors.initials: M
authors.lastname: Egerbacher
authors.affiliation: Institute of Anatomy, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany.
authors.forename: H
authors.initials: H
authors.lastname: Gasse
authors.affiliation: Institute for Pathology, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Hewicker-Trautwein
authors.affiliation: Clinic for Swine and Small Ruminants, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Höltig
authors.affiliation: Clinic for Swine and Small Ruminants, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany.
authors.forename: K-H
authors.initials: KH
authors.lastname: Waldmann
authors.affiliation: Department of Anatomy and Physiology, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas, USA.
authors.forename: F
authors.initials: F
authors.lastname: Blecha
authors.affiliation: Institute of Immunology, Department of Pathobiology, University of Veterinary Medicine Vienna, Austria.
authors.forename: A
authors.initials: A
authors.lastname: Saalmüller
authors.affiliation: University Clinic for Swine, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine Vienna, Vienna, Austria. isabel.hennig-pauka@vetmeduni.ac.at.
authors.forename: I
authors.initials: I
authors.lastname: Hennig-Pauka
mesh_terms: D000189:Actinobacillus Infections / Q000378:metabolism* / Q000382:microbiology / Q000662:veterinary*; D016977:Actinobacillus pleuropneumoniae / Q000378:metabolism*; D000818:Animals; D000942:Antigens, Bacterial / Q000032:analysis / Q000276:immunology; D023181:Antimicrobial Cationic Peptides / Q000032:analysis / Q000378:metabolism*; D017252:CD3 Complex / Q000378:metabolism; D051925:CD79 Antigens / Q000378:metabolism; D019070:Cell Lineage; D023461:Myeloid Progenitor Cells / Q000378:metabolism; D009504:Neutrophils / Q000378:metabolism; D009195:Peroxidase / Q000378:metabolism; D034421:Sus scrofa; D013552:Swine; D013553:Swine Diseases / Q000378:metabolism* / Q000382:microbiology*; D013601:T-Lymphocytes / Q000378:metabolism
chemical_list: D000942:Antigens, Bacterial; D023181:Antimicrobial Cationic Peptides; D017252:CD3 Complex; D051925:CD79 Antigens; C072212:PR 39; D009195:Peroxidase