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Allergy. 2016 Oct;71(10):1425-34. doi: 10.1111/all.12899. Epub 2016 Apr 29.

The minor house dust mite allergen Der p 13 is a fatty acid-binding protein and an activator of a TLR2-mediated innate immune response.

Author information

1
Division of Allergy and Clinical Immunology, Department of Medicine; and Chula Vaccine Research Center (Chula VRC), Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand.
2
Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK.
3
BIO-Bioinfo Department, Université Libre de Bruxelles, Brussels, Belgium.
4
Stallergenes Greer, Antony, France.
5
Division of Allergy and Immunology, Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand.
6
Center of Excellence in Immunology and Immune Mediated Diseases, Division of Immunology, Department of Microbiology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand.
7
Allergy, Immunology and Rheumatology Unit, Queen Sirikit National Institute of Child Health, Department of Medical Services, Ministry of Public Health, Bangkok, Thailand.
8
Division of Allergy, Immunology and Rheumatology, Department of Medicine, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.
9
Division of Allergy and Clinical Immunology, Department of Medicine, Phramongkutklao Hospital, Bangkok, Thailand.
10
Institute of Molecular Biosciences, Mahidol University, Nakhon Pathom, Thailand.
11
Division of Allergy and Clinical Immunology, Department of Medicine; and Chula Vaccine Research Center (Chula VRC), Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand. alain.j@chula.ac.th.

Abstract

BACKGROUND:

The house dust mite (HDM) allergen Der p 13 could be a lipid-binding protein able to activate key innate signaling pathways in the initiation of the allergic response. We investigated the IgE reactivity of recombinant Der p 13 (rDer p 13), its lipid-binding activities, and its capacity to stimulate airway epithelium cells.

METHODS:

Purified rDer p 13 was characterized by mass spectrometry, circular dichroism, fluorescence-based lipid-binding assays, and in silico structural prediction. IgE-binding activity and allergenic potential of Der p 13 were examined by ELISA, basophil degranulation assays, and in vitro airway epithelial cell activation assays.

RESULTS:

Protein modeling and biophysical analysis indicated that Der p 13 adopts a β-barrel structure with a predominately apolar pocket representing a potential binding site for hydrophobic ligands. Fluorescent lipid-binding assays confirmed that the protein is highly selective for ligands and that it binds a fatty acid with a dissociation constant typical of lipid transporter proteins. The low IgE-binding frequency (7%, n = 224) in Thai HDM-allergic patients as well as the limited propensity to activate basophil degranulation classifies Der p 13 as a minor HDM allergen. Nevertheless, the protein with its presumptively associated lipid(s) triggered the production of IL-8 and GM-CSF in respiratory epithelial cells through a TLR2-, MyD88-, NF-kB-, and MAPK-dependent signaling pathway.

CONCLUSIONS:

Although a minor allergen, Der p 13 may, through its lipid-binding capacity, play a role in the initiation of the HDM-allergic response through TLR2 activation.

KEYWORDS:

Der p 13; IgE reactivity; TLR2; allergen; house dust mite; innate immunity; lipid-binding protein

PMID:
27018864
DOI:
10.1111/all.12899
[Indexed for MEDLINE]

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