title: Pulmonary expression of tumor necrosis factor alpha, interleukin-1 beta, and interleukin-8 in the acute phase of bovine pneumonic pasteurellosis.
abstract: Inflammatory cytokines are suspected to contribute to the pathogenesis of bovine pneumonic pasteurellosis (BPP) through neutrophil recruitment, leukocyte activation, and the induction of a broad array of soluble inflammatory mediators. An in vivo experimental model of BPP was used to characterize the pulmonary expression kinetics of tumor necrosis factor alpha (TNFalpha), interleukin-1 beta (IL-1beta), and interleukin-8 (IL-8) genes and proteins during the acute phase of disease development. Cytokine expression in bronchoalveolar lavage (BAL) fluid, BAL cells, and pneumonic lung parenchyma was quantitated by northern blot analysis, enzyme-linked immunosorbent assay (ELISA), and in situ hybridization at 2, 4, 8, 16, and 24 hours after endobronchial inoculation of Pasteurella (Mannheimia) haemolytica. Expression of TNFalpha, IL-1beta, and IL-8 was significantly increased in the airways and lung lesions of infected calves as compared with mock-infected controls. Although kinetic patterns varied, peak levels of cytokine mRNA occured within 8 hours postinfection (PI), and peak cytokine concentrations occurred within 16 hours PI. In all samples, IL-8 was expressed to the greatest extent and TNFalpha was least expressed. Expression of TNFalpha was restricted to alveolar macrophages. Alveolar and interstitial macrophages produced IL-1beta and IL-8 in the first 4 hours; bronchial and bronchiolar epithelial cells were also significant sources of IL-8 during this period. By 8 hours PI, neutrophils were the dominant source of both IL-1beta and IL-8. These findings demonstrate a spatial and temporal association between pulmonary expression of inflammatory cytokines and acute lung pathology, supporting the hypothesis that cytokines contribute to inflammatory lung injury in BPP.
authors.affiliation: Department of Clinical and Population Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, USA.
authors.forename: C
authors.initials: C
authors.lastname: Malazdrewich
authors.forename: T R
authors.initials: TR
authors.lastname: Ames
authors.forename: M S
authors.initials: MS
authors.lastname: Abrahamsen
authors.forename: S K
authors.initials: SK
authors.lastname: Maheswaran
mesh_terms: D000818:Animals; D015152:Blotting, Northern / Q000662:veterinary; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D002417:Cattle; D002418:Cattle Diseases / Q000378:metabolism* / Q000382:microbiology / Q000473:pathology; D016207:Cytokines / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D007091:Image Processing, Computer-Assisted; D017403:In Situ Hybridization / Q000662:veterinary; D007375:Interleukin-1 / Q000096:biosynthesis; D016209:Interleukin-8 / Q000096:biosynthesis; D008168:Lung / Q000378:metabolism* / Q000382:microbiology / Q000473:pathology; D008297:Male; D016978:Mannheimia haemolytica / Q000737:chemistry / Q000235:genetics / Q000254:growth & development*; D012766:Pasteurellosis, Pneumonic / Q000378:metabolism* / Q000382:microbiology / Q000473:pathology; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D018709:Statistics, Nonparametric; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis
chemical_list: D016207:Cytokines; D007375:Interleukin-1; D016209:Interleukin-8; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha