Importance of tropomyosin in the allergy to household arthropods. Cross-reactivity with other invertebrate extracts.

The aim of the study was to investigate the involvement of the actin binding protein tropomyosin in the allergic sensitization of patients to household arthropods, as well as to study its panallergenic character in relation to other invertebrate extracts. Three arthropod extracts were prepared, namely fly (Musca domestica), moth (Ephestia spp.) and spider (Tegenaria spp.), and used to evaluate by cutaneous and RAST tests a population of 100 household arthropod allergic patients. Twenty-nine sera were selected for the subsequent SDS-PAGE Immunoblotting assays. IgE binding bands at 36, 34, 31, 27 and 17 kDa were detected in the fly extract by more than 50% of tested sera. In moth and spider extracts, the more relevant allergens were found at 34, 31, 24 and 110, 38, 35, 26, 19 kDa, respectively. A commercial polyclonal antiserum anti-chicken muscle tropomyosin was used for tropomyosin identification. Cross-reactivity studies performed by SDS-PAGE Immunoblotting, using a pool of household arthropod allergic patients and tropomyosin antiserum, preliminarily demonstrated the presence of such protein as a cross-reacting allergen in a large variety of extracts obtained from insects, mites, crustaceans, mollusks and parasites.