Cross–Reactivity between Dermatophagoides siboney and Other Domestic Mites

Abstract

Background: Dermatophagoides siboney (Ds) cross–reacted with other mite allergens in mite–allergic patients. The aim of this study was to investigate the cross–reactivity between individual allergens responsible for this cross–reactivity. Methods: The inhibition of IgE binding to Ds allergens was investigated by non–reducing SDS–PAGE and Western blotting. Nitrocellulose membranes were incubated with a pool of sera from mite–sensitive asthmatics, after the addition of serial dilutions of D. farinae (Df), D. pteronyssinus (Dp), D. microceras (Dm), Lepidoglyphus destructor (Ld), Tyrophagus putrescentiae (Tp), Acarus siro (As) and Blomia tropicalis (Bt). N–terminal amino acid sequences and amino acid analysis of the purified major allergens, Der s 1, 2 and 3, were performed after transfer to polyvinylidene difluoride membranes. Results: The inhibition was higher with Df (86%), Dp (54%) and Dm (49%) extracts than with Ld (20%), Tp (11%), As (18%) and Bt (6%). The dose–response inhibition showed a diverse pattern for the individual allergens. Despite the high cross–reactivity between the pyroglyphid mites, some proteins of Ds were less inhibited, e.g. by the Df and Dp 80–kD protein, and by the Dm and Dp 52–, 37–, 30– and 14–kD allergens. The 65–, 62–, 37– and 30–kD proteins were always inhibited more than 50% by all the mite extracts at the maximum concentration used. The 80–, 52–, 43–, 27– and 14–kD proteins cross–reacted to a lesser extent. Individual allergens of Ds were much less inhibited by non–pyroglyphid mites. However, at the highest concentration, Ld also inhibited most of the Ds allergens. All the ten selected allergens were inhibited to some extent by the heterologous mite extracts. The N–terminal sequences of Der s 1, 2 and 3 allergens showed higher homology to Df and Dm than to Dp. The homology of the group 2 allergens was higher than that of the group 1 allergens. Conclusion: The individual allergens of Ds were more similar to Df and Dm than to Dp. There was a limited and variable cross–reactivity with non–pyroglyphid mites. No single allergen was unique for Ds.