Antigen 5 Allergens of Hymenoptera Venoms and Their Role in Diagnosis and Therapy of Venom Allergy.

PURPOSE OF REVIEW: Stings of Hymenoptera of the superfamily Vespoidea such as yellow jackets, paper wasps or stinging ants are common triggers for severe and even fatal allergic reactions. Antigen 5 allergens are potent allergens in the majority of these venoms with major importance for diagnosis and therapy. Reviewed here are the characteristics of antigen 5 allergens, their role in component-resolved diagnostics as well as current limitations of the available diagnostics for proper therapeutic decisions. RECENT FINDINGS: Antigens 5 are proteins of unknown function in Hymenoptera venoms with high allergenic potency. They represent key elements in component-resolved diagnosis to discriminate between honeybee and vespid venom allergy. However, due to their pronounced cross-reactivity, there are remaining diagnostic and therapeutic challenges that have to be addressed. Antigens 5 are highly relevant venom allergens of the Vespoidea superfamily. Although their use in component-resolved diagnosis facilitates dissection of cross-reactivity and primary allergy in double sensitization to honeybee and vespid venom, new diagnostic concepts are needed to discriminate between allergies to different vespid species.

Análise proteômica das principais proteínas antigênicas do veneno da vespa agelaia pallipes / Proteomic analysis of mayor antigenic proteins from agelaia pallipes venom

Objetivo: alguns pacientes alérgicos ao veneno de vespas apresentam pesquisa negativa de IgE específica com os extratos disponíveis. Para investigar esta falta de reação cruzada, este estudo pretende caracterizar os antígenos principais do veneno de uma das espécies encontradas no Brasil, a Agelaia pallipes, utilizando a análise proteômica. Método: realizamos eletroforese bidimensional com veneno de Agelaia pallipes. Na primeira dimensão utilizamos tiras de gel de 7 cm com gradiente de pH de 3.0 -10.0, e na segunda SDS-PAGE 15%. Com géis feitos em duplicata, o primeiro foi transferido para nitrocelulose e incubado com o soro de paciente sensibilizado (diluição 1:5). A imunodetecção foi realizada com anti-IgE humana biotinilada e ECL (Enhanced Chemiluminescence). No segundo gel, corado Coomassie, os spots correspondentes às proteínas reconhecidas pela IgE através do immuniblotting foram processados e analisados no espectrometro de massa do tipo MALDI-ToF. A identificação foi obtida por PMF - Peptide Mass Fingerprinting. Resultados: a eletroforese bidimensional com o veneno da Agelaia pallipes evidenciou várias proteínas com peso molecular (PM) abaixo de 20kDa. Com immunoblotting foram detectadas proteínas reconhecidas pela IgE com PM entre 20 e 38 kDa. Pela análise proteômica, estas proteínas foram identificadas principalmente como antígeno 5 e serino-proteases. Conclusão: este é o primeiro trabalho a identificar alérgenos de vespas neotropicais com análise proteômica. Além do antígeno 5, identificamos serino-proteases que apenas recentemente foram citadas neste tipo de amostra biológica, mostrando semelhança parcial entre estas proteínas de venenos de vertebrados (serpentes). Nosso projeto futuro será o sequenciamento das amostras.

Mononuclear blood cell sulfidoleukotriene generation in the presence of interleukin-3 and whole blood histamine release in honey bee and yellow jacket venom allergy.

Cross-linking IgE on basophils is known to cause both sulfidoleukotriene (sLT) generation and histamine release. We recently developed an ELISA to determine sulfidoleukotriene generation by blood mononuclear cells which employs pretreatment with IL-3 to enhance leukotriene generation (cellular antigen stimulation test, CAST). Here, we compared the CAST and whole blood histamine release in response to honey bee/yellow jacket venom (BV/YJV) in 23 patients clinically suspected of type-I allergy to these venoms. Of these, 17 were diagnosed as "definitive venom allergics," defined by a positive skin test at 100 ng/ml of venom or less. The six in whom such skin reactivity was absent were labelled "suspected venom allergics." Both venoms stimulated sulfidoleukotriene generation and histamine release also from control individuals (n = 10). In patients, insect venoms generally stimulated histamine release and sulfidoleukotriene generation in excess of the mean + 3 SD of values obtained with control individuals. However, about half of the patients reacted predominantly with either histamine release or sulfidoleukotriene generation. No overall correlation was found between threshold doses necessary to stimulate sulfidoleukotriene generation (ThsLT) and histamine release (ThHist). (Linear correlation coefficients between ThsLT and ThHist were -0.02 for honey bee venom and 0.13 for yellow jacket, n = 23). Both findings are in contrast to the concept that these responses occur in parallel. From results with "definitive venom allergics," CAST sensitivity was calculated as 100% for honey bee venom and 83% for yellow jacket, and that of the histamine release assay as 62.5% for honey bee venom and 50% for yellow jacket. Specificity of the CAST was calculated as 77% for honey bee venom and 100% for yellow jacket, and that of the histamine release assay as 44% for honey bee venom and 60% for yellow jacket. Thus, CAST results are closer to skin test results than to those of the whole blood histamine release assay.