An immunoproteomic approach revealed antigenic proteins enhancing serodiagnosis performance of bird fancier's lung

J Immunol Methods. 2017 Nov:450:58-65. doi: 10.1016/j.jim.2017.07.012. Epub 2017 Jul 29.

Abstract

Background: Bird fancier's lung (BFL) caused by repeated inhalation of avian proteins is the most common form of hypersensitivity pneumonitis. However, the exact identification of proteins involved is unknown, and serological test use for diagnosis need to be standardized. The objectives of this study were (i) to identify antigenic proteins from pigeon droppings (ii) to provide information about their location in avian matrices and (iii) to produce them in recombinant proteins to evaluate their diagnostic performances.

Method: Antigenic proteins of pigeon dropping extracts were investigated using 2-dimensional immunoblotting with sera from patients with BFL, asymptomatic exposed controls and healthy volunteers. We investigated the origin of these antigenic proteins by analyzing droppings, blooms and sera using a shotgun proteomic analysis. BFL-associated proteins were produced as recombinant antigens in E. coli and were assessed in ELISA with sera from patients (n=25) and subject exposed controls (n=30). These diagnostic performances were compared with those obtained by precipitin techniques (agar gel double diffusion, immunoelectrophoresis).

Results: We identified 14 antigenic proteins mainly located in droppings and blooms. These proteins were involved in either the digestive or immune systems of pigeons. Using the recombinant BFL-associated proteins: Immunoglobulin lambda-like polypeptide-1 (IGLL1: sensitivity: 76%; specificity: 100%; AUC: 0.93) and Proproteinase E (ProE: sensitivity: 84%; specificity: 80%; AUC: 0.85), the ELISA test showed better performance than precipitin assays with pigeon dropping extracts (sensitivity: 60%; specificity: 93.3%; AUC: 0.76).

Conclusion: IGLL1 and ProE were identified as the biomarkers of the disease. The use of these highly standardized antigens discriminates BFL cases from exposed subjects in serological assays. The results of this study offer new possibilities for the serological diagnosis of the disease.

Clinical trial registration: ClinicalTrials.gov: Identifier NCT03056404.

Keywords: 2D electrophoresis; Bird fancier's lung; ELISA; Hypersensitivity pneumonitis; Recombinant antigens; Serodiagnosis.

Publication types

  • Comparative Study

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Allergens / immunology*
  • Animals
  • Area Under Curve
  • Avian Proteins / immunology*
  • Bird Fancier's Lung / blood
  • Bird Fancier's Lung / diagnosis*
  • Bird Fancier's Lung / immunology
  • Birds / immunology*
  • Case-Control Studies
  • Chromatography, Liquid
  • Electrophoresis, Agar Gel
  • Electrophoresis, Gel, Two-Dimensional
  • Endopeptidases / immunology
  • Enzyme Precursors / immunology
  • Enzyme-Linked Immunosorbent Assay*
  • Feces*
  • Female
  • Humans
  • Immunoelectrophoresis
  • Immunoglobulin Light Chains, Surrogate / immunology
  • Inhalation Exposure
  • Male
  • Middle Aged
  • Predictive Value of Tests
  • Proteomics / methods*
  • ROC Curve
  • Reproducibility of Results
  • Serologic Tests*
  • Tandem Mass Spectrometry

Substances

  • Allergens
  • Avian Proteins
  • Enzyme Precursors
  • IGLL1 protein, human
  • Immunoglobulin Light Chains, Surrogate
  • Endopeptidases
  • pro-proteinase E

Associated data

  • ClinicalTrials.gov/NCT03056404