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Molecular cloning and immunological characterization of the house dust mite allergen Der f 7
Author(s) -
SHEN H.D.,
CHUA K.Y.,
LIN W.L.,
HSIEH K.H.,
THOMAS W. R.
Publication year - 1995
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.1365-2222.1995.tb00403.x
Subject(s) - microbiology and biotechnology , complementary dna , house dust mite , allergen , immunoglobulin e , gel electrophoresis , chemistry , molecular cloning , peptide sequence , antibody , monoclonal antibody , biology , serology , biochemistry , allergy , immunology , gene
Summary Background The allergen Der p 7 from Dermatophagoides pteronyssinus has been defined by molecular cloning and shown to be an important specificity in 50% of miteallergic patients. Objective This study compares the cDNA sequence and serological reactivity of Der f 7 from D . farinae with Der p 7. Method cDNA encoding Der f 7 was amplified by polymerase chain reaction. sequenced and expressed as a fusion with glutathione‐S‐transferase for IgE and monoclonal antibody binding studies. Results Der f 7 cDNA encoded a 213 polypeptide containing a predicted 17 amino acid leader sequence, no cysteines and a single N‐glycosylation site similar to Der p 7. The predicted 196 residue mature polypeptide had 86% identity lo Der p 7 and a calculated molecular weight of 22 34SDa. No homologues were found in searches of the data banks. The Der f 7 fusion protein showed a single band of 46 k Da by sodium dodccyl snlfute‐polyaerylamide gel electrophoresis (SDS‐PAGF) and reacted with IgE antibodies in 19/41 (46%) of sera from asthmatic children. The degree of binding was usually 30% of that to Der p 7 consistent with the exposure of the patients to D. Pteronyssinus . Monoclonal antibodies (WH9 and WH22) against Der p 7 reacted with Der f 7 but inhibition studies showed a 10‐fold difference in reactivity. Conclusion Der f 7 has a predicted 213 residue polypeptide with 86% homology and serological cross reactivity to Der p 7.