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Characterization of recombinant Mal d 4 and its application for component‐resolved diagnosis of apple allergy
Author(s) -
Ma Y.,
Zuidmeer L.,
Bohle B.,
Bolhaar S.T.H.,
Gadermaier G.,
GonzalezMancebo E.,
FernandezRivas M.,
Knulst A.C.,
Himly M.,
Asero R.,
Ebner C.,
Van Ree R.,
Ferreira F.,
Breiteneder H.,
HoffmannSommergruber K.
Publication year - 2006
Publication title -
clinical and experimental allergy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.462
H-Index - 154
eISSN - 1365-2222
pISSN - 0954-7894
DOI - 10.1111/j.1365-2222.2006.02541.x
Subject(s) - recombinant dna , immunoglobulin e , basophil activation , escherichia coli , allergen , profilin , allergy , circular dichroism , histamine , microbiology and biotechnology , biochemistry , chemistry , hypoallergenic , biology , immunology , basophil , gene , antibody , pharmacology , actin cytoskeleton , cytoskeleton , cell
Background Profilins are ubiquitous panallergens that have been extensively characterized; yet, their clinical relevance is still unclear. Objective The aim of the present study was to produce recombinant apple profilin (rMal d 4) and to evaluate its allergenic activity and its potency for component‐resolved allergy diagnosis. Methods Complementary DNA‐derived Mal d 4 was cloned, expressed in Escherichia coli and subsequently purified via poly ( l ‐proline) sepharose. A total of 28 sera from apple‐allergic patients were used for IgE‐ELISA, immunoblot, RAST and basophil histamine release (BHR) test. In addition, skin prick tests (SPTs) were performed in five patients. Results Four different complementary DNA coding for apple profilin, Mal d 4, each with an open reading frame of 393 nucleotides, were identified. One isoform Mal d 4.0101 was expressed in Escherichia coli and subsequently purified. Mass spectroscopy revealed the expected mass of 13.826 for rMal d 4.0101, and circular dichroism analysis data were typical for a folded protein and small‐angle X‐ray scattering measurement identified the protein as a monomer. All the serum samples displayed IgE binding to rMal d 4.0101 in IgE ELISA, immunoblot and RAST. In immunoblotting, IgE binding to natural Mal d 4 was partially/completely inhibited by preincubation with rMal d 4.0101, and RAST values to apple extract were significantly reduced upon serum pretreatment with rMal d 4.0101. SPTs and BHR assays using purified rMal d 4.0101 were positive. Purified rMal d 4.0101 was destroyed within seconds when subjected to pepsin digestion. Conclusions Apple profilin complementary DNAs were identified. The physicochemical and allergenic properties of purified recombinant Mal d 4.0101 were evaluated showing that the recombinant protein was equal to the natural protein as shown by inhibition assays. Thus, Mal d 4 represents another example suitable for component‐resolved diagnosis of food allergy.