Evaluation of protein expression in bovine bronchoalveolar fluid following challenge with Mannheimia haemolytica

• Published in: Proteomics (Weinheim) 2011-09, Vol.11 (18), p.3685-3697
• Main Authors: Boehmer, Jamie L., DeGrasse, Jeffrey A., Lancaster, Vicki A., McFarland, Melinda A., Callahan, John H., Ward, Jeffrey L.
• Format: Article
• Language: English
• Subjects: Acute phase substances; Alveoli; Analytical, structural and metabolic biochemistry; Animal proteomics; Animals; Antimicrobial peptides; Antimicrobial protein; Biological and medical sciences; Bovine bronchoalveolar fluid; Bronchoalveolar Lavage Fluid - chemistry; Bronchoalveolar Lavage Fluid - immunology; Bronchoalveolar Lavage Fluid - microbiology; Bronchus; Cathelicidins - analysis; Cattle; Cattle - metabolism; Cattle - microbiology; Cattle Diseases - immunology; Cattle Diseases - microbiology; Chromatography, Liquid; Data processing; Enzyme-Linked Immunosorbent Assay; Fundamental and applied biological sciences. Psychology; Haptoglobin; Haptoglobins - analysis; Infection; Liquid chromatography; Male; Mannheimia haemolytica; Mannheimia haemolytica - immunology; Mannheimia haemolytica - pathogenicity; Mass spectroscopy; Miscellaneous; MS/MS; Mucosa; Nanoflow LC; Peptide Fragments - analysis; Pneumonia; Pneumonia of Calves, Enzootic - immunology; Pneumonia of Calves, Enzootic - microbiology; Protein expression; Proteinase inhibitors; Proteins; Proteome - analysis; Proteomics; Statistics; Tandem Mass Spectrometry
• ISSN: 1615-9853; 1615-9861
• DOI: 10.1002/pmic.201000710

Proteomics analysis of bovine bronchoalveolar fluid (BAF) following induction of pneumonia with Mannheimia haemolytica using nanoflow liquid chromatography coupled with tandem mass spectrometry (nanoLC‐MS/MS) resulted in the identification of 88 unique proteins. Proteins detected in BAF included antimicrobial peptides (AMPs), complement factors, acute‐phase proteins, protease inhibitors, and proteins involved in oxidation–reduction. Notwithstanding biological variation, differences in relative protein abundance, determined using normalized peptide counts, were detected for select proteins in BAF from genuinely infected versus sham‐infected animals. To demonstrate the applicability of using normalized peptide counts to assess protein expression trends, LC‐MS/MS data for the acute‐phase protein haptoglobin (HPT) were compared with ELISA data, and statistical evaluation of the relationship between the data revealed a strong measure of association. Differences were detected between sham‐ and genuinely infected animals for haptoglobin, as well as the AMPs cathelicidin‐1 and cathelicidin‐4, and inter‐α‐trypsin inhibitor heavy chain‐4, a fairly novel protein involved in the acute phase response. Though the small sample size limited the scope of the inferences, the results indicate the likely importance of AMPs and acute‐phase proteins during respiratory infection, and provide additional information regarding potential mechanisms involved in the bovine mucosal barrier defense.