There is cross-reactivity between Ascaris and mites, determined by several allergens including tropomyosin and glutathione-S-transferase. In addition to its potential impact on asthma pathogenesis, Ascaris infection and mite allergy diagnosis relying on the determination of specific IgE could be affected by this cross-reactivity. ABA-1 has no cross-reactive counterpart in mite extracts, suggesting its usefulness as a more specific marker of Ascaris infection.

Plaque radio-immuno assay has been used to isolate an IgE-binding clone from a lambda gt11 library of Dermatophagoides pteronyssinus cDNA. The clone HD6 contained DNA encoding a 215 residue protein which contained a predicted 17 amino acid residue leader sequence, no cysteines and a single N-glycosylation site. The 198 residue mature protein would have a predicted MW of 22,177 D. No homologues were found in searches of the data banks. Sera from 14/38 allergic children reacted strongly with the polypeptide produced by the clone (37%). Skin tests showed reactivity in 16/30 (53%) allergic patients and 0/10 of controls. Affinity purification of rabbit antibodies with the clone showed that antibodies to the polypeptide had specificities to multiple products in mite extracts corresponding to components of Mr 29, 27 and 24 K by Western blotting. Absorption studies of IgE in allergic serum indicated further entities at 13 and 11.5 kD. It is proposed to name this allergen Der p VII.

The present study extended our understanding of the primary structure of isoforms of Cyn d 1.

No abstract