RESUMO
INTRODUCTION: Allergen-specific immunotherapy (AIT) represents a curative approach for treating allergies. In the tropical and subtropical regions of the world, Blomia tropicalis (Blo t 5 and Blo t 21) is the likely dominant source of indoor allergens. AIM: To generate a hypoallergenic Blo t 5/Blo t 21 hybrid molecule that can treat allergies caused by B tropicalis. METHODS: Using in silico design of B tropicalis hybrid proteins, we chose two hybrid proteins for heterologous expression. Wild-type Blo t 5/Blo t 21 hybrid molecule and a hypoallergenic version, termed BTH1 and BTH2, respectively, were purified by ion exchange and size exclusion chromatography and characterized by physicochemical, as well as in vitro and in vivo immunological, experiments. RESULTS: BTH1, BTH2 and the parental allergens were purified to homogeneity and characterized in detail. BTH2 displayed the lowest IgE reactivity that induced basophil degranulation using sera from allergic rhinitis and asthmatic patients. BTH2 essentially presented the same endolysosomal degradation pattern as the shortened rBlo t 5 and showed a higher resistance towards degradation than the full-length Blo t 5. In vivo immunization of mice with BTH2 led to the production of IgG antibodies that competed with human IgE for allergen binding. Stimulation of splenocytes from BTH2-immunized mice produced higher levels of IL-10 and decreased secretion of IL-4 and IL-5. In addition, BTH2 stimulated T-cell proliferation in PBMCs isolated from allergic patients, with secretion of higher levels of IL-10 and lower levels of IL-5 and IL-13, when compared to parental allergens. CONCLUSIONS AND CLINICAL RELEVANCE: BTH2 is a promising hybrid vaccine candidate for immunotherapy of Blomia allergy. However, further pre-clinical studies addressing its efficacy and safety are needed.
Assuntos
Alérgenos , Proteínas de Artrópodes , Hipersensibilidade , Ácaros , Vacinas , Alérgenos/genética , Alérgenos/imunologia , Alérgenos/farmacologia , Animais , Proteínas de Artrópodes/genética , Proteínas de Artrópodes/imunologia , Proteínas de Artrópodes/farmacologia , Citocinas , Feminino , Humanos , Hipersensibilidade/imunologia , Hipersensibilidade/terapia , Masculino , Camundongos Endogâmicos BALB C , Ácaros/genética , Ácaros/imunologia , Vacinas/genética , Vacinas/imunologia , Vacinas/farmacologiaRESUMO
Fag s 1 is a member of the Pathogen Related protein family 10 (PR-10) and can elicit cross-reaction with IgE antibodies produced against the birch pollen allergen Bet v 1. The Nuclear Magnetic Resonance (NMR) structure of Fag s 1 is presented along with its dynamic properties. It shares 66% identity with Bet v 1 and exhibits the expected three α-helices and seven ß-sheets arranged as a semi-beta barrel and exposing the residues mapped as the Bet v 1 IgE epitope. The structural dynamics of Fag s 1 were monitored on the fast and intermediate timescales, using relaxation rates. The complex dynamics of Fag s 1 are closely related to the internal cavity, and they modulate IgE and ligand binding.
Assuntos
Alérgenos/imunologia , Antígenos de Plantas/química , Reações Cruzadas , Fagus/imunologia , Proteínas de Plantas/química , Antígenos de Plantas/imunologia , Antígenos de Plantas/isolamento & purificação , Betula/imunologia , Epitopos/imunologia , Humanos , Simulação de Dinâmica Molecular , Ressonância Magnética Nuclear Biomolecular , Proteínas de Plantas/imunologia , Proteínas de Plantas/isolamento & purificação , Pólen/imunologia , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína , Proteínas Recombinantes/química , Proteínas Recombinantes/imunologia , Proteínas Recombinantes/isolamento & purificação , Relação Estrutura-AtividadeRESUMO
Allergic diseases are considered a major problem for healthcare systems in both developed and developing countries. House dust mites are well-known triggers of allergic manifestations. While the Dermatophagoides genus is widely distributed globally, Blomia tropicalis is the most prominent mite species in the tropical and subtropical regions of the world. Over the last decades, an increase in sensitization rates to B. tropicalis has been reported, leading to increased research efforts on Blomia allergens. In fact, 8 new allergens have been identified and characterized to different degrees. Here, we provide an overview of recent developments concerning the identification and production of recombinant Blomia allergens, as well as their structural and immunological characterization. Although considerable progress has been achieved, detailed molecule-based studies are still needed to better define the clinical relevance of Blomia allergens. Thus, the establishment of a well-standardized and fully characterized panel of allergens remains a challenge for the development of better diagnosis and therapy of allergic diseases induced by B. tropicalis.