Molecular cloning and immunological characterization of the house dust mite allergen Der f 7
Article first published online: 27 APR 2006
Clinical & Experimental Allergy
Volume 25, Issue 10, pages 1000–1006, October 1995
How to Cite
SHEN, H.-D., CHUA, K.-Y., LIN, W.-L., HSIEH, K.-H. and THOMAS, W. R. (1995), Molecular cloning and immunological characterization of the house dust mite allergen Der f 7. Clinical & Experimental Allergy, 25: 1000–1006. doi: 10.1111/j.1365-2222.1995.tb00403.x
- Issue published online: 27 APR 2006
- Article first published online: 27 APR 2006
- Submitted 11 October 1994; revised 20 January 1995; accepted 18 April 1995.
- house dust mite;
- Der f 7;
- cDNA cloning;
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.