Molecular cloning and the allergenic characterization of tropomyosin from Tyrophagus putrescentiae.
ABSTRACT Storage mites have been recognized as a cause of asthma and rhinitis. Studies from several countries have shown that the IgE-mediated allergy to storage mites is of considerable importance, especially in rural populations. This study aimed to identify and characterize new allergens from Tyrophagus putrescentiae. A partial cDNA sequence encoding tropomyosin was isolated from the cDNA library by immunoscreening using anti-mouse IgG1 sera raised against T. putrescentiae whole body extract. The deduced amino acid sequence shares 64-94% identity with previously known allergenic tropomyosins. Its recombinant protein was produced by using a pET 28b expression system and purified by affinity chromatography using Ni-NTA agarose. The IgE reactivities of tropomyosins from T. putrescentiae and Dermatophagoides farinae were compared by enzyme linked immunosorbent assay (ELISA). Recombinant Tyr p 10 showed 12.5% (5/40) IgE-binding reactivity, whereas recombinant Der f 10 showed 25% (10/40) IgE-binding reactivity against the same sera from storage mite-sensitized and house dust mite-sensitized subjects. Both recombinant Tyr p 10 and Der f 10 showed little inhibition of IgE binding to T. putrescentiae crude extract by ELISA. Tropomyosin seems to contribute only a small portion of the cross-reactivity with house dust mites.
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ABSTRACT: Although specific IgE to the storage mite Acarus siro is often detected, there are no detailed studies on IgE reactivity to A. siro in Korea. This study was undertaken to investigate the cross-reactivity to the mite species Dermatophagoides pteronyssinus, Dermatophagoides farinae, Tyrophagus putrescentiae, and A. siro in Korean mite allergic patients. Specific IgE values were determined for the four mite species and a competitive inhibition test was performed for mite extracts using the ImmunoCAP system. The IgE value to D. farinae was the highest among the four mite species tested. There was a strong correlation in the IgE value between house dust mites (D. pteronyssinus and D. farinae) and between storage mites (A. siro and T. putrescentiae). IgE reactivity to A. siro was inhibited by D. farinae and T. putrescentiae extract. Dermatophagoides farinae extract was the strongest inhibitor of IgE binding to A. siro extract, indicating that IgE reactivity to A. siro extract is a cross-reaction caused by sensitization to D. farinae. Strong IgE reactive components were observed in D. farinae and T. putrescentiae extract by SDS-PAGE and IgE immunoblotting. However, no strong IgE-binding component was observed for A. siro. Dermatophagoides farinae is the main source of mite allergens that cause sensitization in Korea. Serum IgE from some of the house dust mite-sensitized patients showed positive responses to storage mite allergens by cross-reaction. Therefore, it is necessary to pay special attention to the diagnosis of mite allergies.Experimental and Applied Acarology 11/2013; · 1.82 Impact Factor
Article: Mites and allergy.[Show abstract] [Hide abstract]
ABSTRACT: Allergic diseases triggered by mite allergens include allergic rhinoconjunctivitis, asthma, atopic dermatitis and other skin diseases. Since the early discovery of the allergenic role of mites of the genus Dermatophagoides in the mid 1960s, numerous species have been described as the source of allergens capable of sensitizing and inducing allergic symptoms in sensitized and genetically predisposed individuals. The main sources of allergens in house dust worldwide are the fecal pellets of the mite species D. pteronyssinus, D. farinae, Euroglyphus maynei and the storage mites Blomia tropicalis, Lepidoglyphus destructor and Tyropahgus putrescentiae. Group 1 and 2 allergens are major house dust mite allergens. The main allergens in storage mites include fatty acid-binding proteins, tropomyosin and paramyosin homologues, apolipophorin-like proteins, α-tubulins and others, such as group 2, 5 and 7 allergens. Cross-reactivity is an important and common immunological feature among mites. Currently, purified native or recombinant allergens, epitope mapping, proteomic approaches and T cell proliferation techniques are being used to assess cross-reactivity. Mites contain potent enzymes capable of degrading a wide range of substrates. Most mite allergens are enzymes. Advances in genomics and molecular biology will improve our ability to understand the genetics of specific IgE responses to mites. Mite allergen avoidance and immunotherapy are the only two allergen-specific ways to treat mite-induced respiratory and cutaneous diseases. © 2014 S. Karger AG, Basel.Chemical immunology and allergy 01/2014; 100:234-42.