Allergenic characterization of the domestic mite Dermatophagoides siboney
Sammanfattning: Allergic reactions to Pyroglyphid mites of the genus Dennatophagoides play an important role in the pathogenesis of asthma and other atopic diseases. Dermatophagoides siboney was described in Cuba in 1982. D. pteronyssinus and D. siboney are the most frequent mites in house dust collected from the homes of Cuban asthmatics, i.e., 100 and 85%, respectively.The aims of the present studies were to investigate the prevalence of sensitization to D. siboney, Blomia tropicalis and other mite species in asthmatic patients from Cuba; to study the allergenic composition and to characterize the major allergens of D. siboney extracts; to investigate the crossreactivity between D. siboney and other mite allergens, and the relevance of patient selection for the determination of the biological activity of D. siboney and other domestic mites in the tropics.Dermatophagoides siboney was found to be an important sensitizing agent among asthmatics in Cuba. Sensitization to B. tropicalis, D. pteronyssinus, D. farinae and A. siro, was also common as studied by skin and specific IgE tests. A combination of SPT with D. siboney, D. pteronyssinus and B. tropicalis diagnosed sensitization to mites in almost all mite sensitive patients. Thirteen allergenic proteins were identified in D. siboney extracts. Three components, 25, 14 and 30 kD, which bound to specific IgE strongly and frequently, were purified by affinity chromatography using crossreacting monoclonal antibodies to group 1; 2 and 3 allergens and named Der s 1, Der s 2 and Der s 3, respectively. TheN-terminal sequences of these allergens showed higher homology with D. jarinae and D. microceras than with D. pteronyssinus. The homology between group 2 allergens was higher than that of group 1 and 3 allergens.A higher degree of crossreactivity was observed between allergens from D. siboney and D. farinae than betWeen D. siboney and D. pteronyssinus, B. tropicalis, A. siro, L. destructor or T. putrescentiae. Due to the crossreactivity, Cubans not exposed to D. farinae and Swedes not exposed to D. siboney and B. tropicalis, reacted to these mites. The individual allergens of D. siboney crossreacted more with those of D. farinae and D. microceras than with those of D. pteronyssinus. The 65, 62, 37 and 30 kD proteins, always inhibited by more than 50 % by the other mite species, were the main cause of the crossreactivity, The 80 kD protein was the less crossreactive allergen. Three MoAbs directed to Der s 1, one group crossreacting and two species specific, were produced. The crossreacting monoclonal antibody partly inhibited IgE binding to Der s 1 allergen. The results confmned the existence of crossreacting epitopes onDer s 1 but also indicate that this allergen has at least one species specific epitope.The degree of reactivity to different mites seemed to be more related to patient selection criteria and extract potency rather than to exposure to a specific species.Since D. siboney is common in dust from Cuban homes, it is probably present in other Caribbean countries and found to be an important sensitizer, it has been considered a potential candidate for the development of extracts for diagnosis and therapy of mite allergy. These studies contribute to the understanding of the characteristics of the allergens from this species and their relation to other mite allergens.
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