Sensitization to Blomia tropicalis in patients with asthma and identification of allergen Blo t 5.

Blomia tropicalis (Bt) and Dermatophagoides pteronyssinus (Dp) are the prevalent house dust mites in tropical countries and are associated with allergic diseases. Glycosylated antigens are highly immunogenic and involved in different pathologies. We evaluated the presence of IgE, IgG1, and IgG4 to concanavalin A-binding antigens (Bt-Con-A) isolated from Bt-total extract in sera of allergic and non-allergic subjects. Bt-total and Bt-Con-A extracts were evaluated by SDS-PAGE and ELISA for reacting with IgE, IgG1, and IgG4 in sera of 121 patients with allergic rhinitis and 36 non-allergic individuals. All subjects were skin prick tested with Bt-total extract and inhibition tests were performed for IgE, IgG1, and IgG4 using both extracts (Bttotal and Bt-Con-A). Skin prick test showed that 58% of the patients were sensitized to Bt (Bt+), with 52% reactive to both mites (Bt and Dp) and 6% to Bt only. A broad spectrum of proteins (14-152 kDa) was visualized in Bt-total and components >27 kDa for the Bt-Con-A extract. ELISA showed a similar profile of IgE, IgG1 and IgG4 levels in response to Bt-total and Bt-Con-A extracts in different groups, although Bt+ patients showed a lower IgG4 reactivity to Bt-Con-A extract. Specific IgG1 levels were higher in Bt+ patients than in control subjects, and IgG4 levels showed no significant difference among groups. ELISA inhibition showed a partial IgE and total IgG1 and IgG4 cross-reactivity with Dp extract for Bt-total and Bt-Con-A extracts. We conclude that Con-A-binding components isolated from Bt constitute major allergens and are involved in both allergen sensitization (IgE response) and homeostasis maintenance (IgG1 and IgG4 responses).

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“…Positive skin tests and/or serum IgE antibodies to HDM have been widely demonstrated in genetically predisposed individuals (4).…”

Section: Kc Almeida Et Almentioning

confidence: 99%

Responses of IgE, IgG1, and IgG4 to concanavalin A-binding Blomia tropicalis antigens in allergic patients

Almeida¹,

Silva²,

Gennari-Cardoso³

et al. 2006

Braz J Med Biol Res

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“…Experimental animal models using Dermatophagoides pteronyssinus to induce allergic responses through respiratory sensitization and challenge are now widely used and have led to a greater understanding of allergenicity (2)(3)(4)(5)(6). However, less attention has been paid to another major mite allergen, Blomia tropicalis, which is prevalent in tropical and subtropical regions of the world (7,8), where .2 billion people live. High frequencies of sensitivity to B. tropicalis have been described in asthma and rhinitis patients in those regions, and .20 allergens were identified through their IgE-binding activity (9)(10)(11)(12).…”

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confidence: 99%

GM-CSF–Licensed CD11b+ Lung Dendritic Cells Orchestrate Th2 Immunity to Blomia tropicalis

Zhou

Schlitzer

et al. 2014

The Journal of Immunology

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The Blomia tropicalis dust mite is prevalent in tropical and subtropical regions of the world. Although it is a leading cause of asthma, little is known how it induces allergy. Using a novel murine asthma model induced by intranasal exposure to B. tropicalis, we observed that a single intranasal sensitization to B. tropicalis extract induces strong Th2 priming in the lung draining lymph node. Resident CD11b+ dendritic cells (DCs) preferentially transport Ag from the lung to the draining lymph node and are crucial for the initiation of Th2 CD4+ T cell responses. As a consequence, mice selectively deficient in CD11b+ DCs exhibited attenuated Th2 responses and more importantly did not develop any allergic inflammation. Conversely, mice deficient in CD103+ DCs and CCR2-dependent monocyte-derived DCs exhibited similar allergic inflammation compared with their wild-type counterparts. We also show that CD11b+ DCs constitutively express higher levels of GM-CSF receptor compared with CD103+ DCs and are thus selectively licensed by lung epithelial-derived GM-CSF to induce Th2 immunity. Taken together, our study identifies GM-CSF–licensed CD11b+ lung DCs as a key component for induction of Th2 responses and represents a potential target for therapeutic intervention in allergy.

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“…In tropical climates, Blomia tropicalis is found in addition to Dermatophagoides spp. Indeed, asthmatic patients from Florida, Puerto Rico, and Brazil were found to be sensitized to both D. pteronyssinus and B. tropicalis (6). Patients from the United Kingdom who were sensitized only to D. pteronyssinus gave positive skin tests to B. tropicalis extract, but this apparent cross-reactivity was not due to the group 5 allergens (7).…”

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confidence: 99%

Der p 5 Crystal Structure Provides Insight into the Group 5 Dust Mite Allergens

Mueller

Gosavi

Krahn

et al. 2010

Journal of Biological Chemistry

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Group 5 allergens from house dust mites elicit strong IgE antibody binding in mite-allergic patients. The structure of Der p 5 was determined by x-ray crystallography to better understand the IgE epitopes, to investigate the biologic function in mites, and to compare with the conflicting published Blo t 5 structures, designated 2JMH and 2JRK in the Protein Data Bank. Der p 5 is a three-helical bundle similar to Blo t 5, but the interactions of the helices are more similar to 2JMH than 2JRK. The crystallographic asymmetric unit contains three dimers of Der p 5 that are not exactly alike. Solution scattering techniques were used to assess the multimeric state of Der p 5 in vitro and showed that the predominant state was monomeric, similar to Blo t 5, but larger multimeric species are also present. In the crystal, the formation of the Der p 5 dimer creates a large hydrophobic cavity of ϳ3000 Å 3 that could be a ligand-binding site. Many allergens are known to bind hydrophobic ligands, which are thought to stimulate the innate immune system and have adjuvant-like effects on IgE-mediated inflammatory responses.

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Sensitization to Blomia tropicalis in patients with asthma and identification of allergen Blo t 5.

Cited by 113 publications

References 22 publications

Responses of IgE, IgG1, and IgG4 to concanavalin A-binding Blomia tropicalis antigens in allergic patients

Responses of IgE, IgG1, and IgG4 to concanavalin A-binding Blomia tropicalis antigens in allergic patients

GM-CSF–Licensed CD11b+ Lung Dendritic Cells Orchestrate Th2 Immunity to Blomia tropicalis

Der p 5 Crystal Structure Provides Insight into the Group 5 Dust Mite Allergens

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