The Blomia tropicalis allergen Blo t 7 stimulates innate immune signalling pathways through TLR2.

Autor: Soongrung, T., Mongkorntanyatip, K., Peepim, T., Buaklin, A., Le Mignon, M., Malainual, N., Nony, E., Jacquet, A.
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Zdroj: Clinical & Experimental Allergy; Apr2018, Vol. 48 Issue 4, p464-474, 11p, 1 Diagram, 4 Graphs
Abstrakt: Summary: Background: Although the house dust mite species Blomia tropicalis is a leading cause of allergic diseases in tropical and subtropical regions, the identification and characterization of the allergenic proteins remain incomplete. Objective: We aimed to characterize a recombinant form of Blo t 7 (rBlo t 7) in terms of IgE reactivity, lipid‐binding activity and ability to stimulate innate immunity. Methods: The mature Blo t 7 cDNA was cloned by PCR methods for the expression of a secreted form of the allergen in P. pastoris. The IgE reactivity to purified rBlo t 7 as well as the potential cross‐reactivity with Der p 7 was determined by ELISA. The lipid‐binding capacity of rBlo t 7 was assayed using fluorescent lipid probes. The stimulation of TLR2 signalling pathway by rBlo t 7 was examined in cell activation and reporter assays. Results: The amplified mature Blo t 7 cDNA revealed the presence of a 60 base pair insertion compared with the reference sequence registered in the GenBank database. Multiple protein sequence alignments of group 7 mite allergens confirmed that this longer deduced amino acid sequence was the authentic Blo t 7 polypeptide chain. Analysis of IgE reactivity can classify rBlo t 7 as an intermediate B. tropicalis allergen which displayed weak cross‐reactivity with Der p 7. Purified rBlo t 7 was shown to bind selectively the naturally fluorescent lipid probe cis‐parinaric (cPNA) with a dissociation constant of 2 μmol/L. The group 7 Blomia allergen stimulated the TLR2‐, NF‐kB‐ and MAPK‐dependent production of IL‐8 and GM‐CSF in respiratory epithelial cells. Conclusions & Clinical Relevance: Through its propensity to transport fatty acids/lipids and to stimulate TLR2 signalling pathways in airway epithelial cells, Blo t 7 can represent a key allergen for the initiation of the B. tropicalis‐induced airway inflammation. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index
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