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Characterization of Der p 21, a new important allergen derived from the gut of house dust mites *
Author(s) -
Weghofer M.,
Dall’Antonia Y.,
Grote M.,
Stöcklinger A.,
Kneidinger M.,
Balic N.,
Krauth M.T.,
FernándezCaldas E.,
Thomas W. R.,
Hage M. van,
Vieths S.,
Spitzauer S.,
Horak F.,
Svergun D. I.,
Konarev P. V.,
Valent P.,
Thalhamer J.,
Keller W.,
Valenta R.,
Vrtala S.
Publication year - 2008
Publication title -
allergy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.363
H-Index - 173
eISSN - 1398-9995
pISSN - 0105-4538
DOI - 10.1111/j.1398-9995.2008.01647.x
Subject(s) - allergen , house dust mite , immunoglobulin e , immunology , pyroglyphidae , mite , allergy , chemistry , antibody , biology , botany
Background: The house dust mite (HDM) Dermatophagoides pteronyssinus is a major allergen source eliciting allergic asthma. The aim of the study was to identify new important HDM allergens associated with allergic asthma. Methods: A cDNA coding for a new mite allergen, designated Der p 21, was isolated using immunoglobulin E (IgE) antibodies from patients with allergic asthma out of a D. pteronyssinus expression cDNA library and expressed in Escherichia coli . Results: Circular dichroism analysis of the purified allergen showed that rDer p 21 (14 726 Da) is one of the few mite allergens with an α‐helical secondary structure. The protein exhibited high thermal stability and refolding capacity, and, as determined by small angle X‐ray scattering, formed a dimer consisting of two flat triangles. rDer p 21 bound high levels of patients’ IgE antibodies and showed high allergenic activity in basophil activation experiments. Rabbit anti‐Der p 21 IgG antibodies inhibited mite‐allergic patients’ IgE binding and allowed the ultrastructural localization of the allergen in the midgut (epithelium, lumen and faeces) of D. pteronyssinus by immunogold electron microscopy. Der p 21 revealed sequence homology with group 5 mite allergens, but IgE and IgG reactivity data and cross‐inhibition studies identified it as a new mite allergen. Conclusions: Der p 21 is a new important mite allergen which is liberated into the environment via faecal particles and hence may be associated with allergic asthma.