BACKGROUND: Synthetic contiguous overlapping peptides (COPs) may represent an alternative to allergen extracts or recombinant allergens for allergen specific immunotherapy. In combination, COPs encompass the entire allergen sequence, providing all potential T cell epitopes, while preventing IgE conformational epitopes of the native allergen.METHODS: Individual COPs were derived from the sequence of Bet v 1, the major allergen of birch pollen, and its known crystal structure, and designed to avoid IgE binding. Three sets of COPs were tested in vitro in competition ELISA and basophil degranulation assays. Their in vivo reactivity was determined by intraperitoneal challenge in rBet v 1 sensitized mice as well as by skin prick tests in volunteers with allergic rhinoconjunctivitis to birch pollen.RESULTS: The combination, named AllerT, of three COPs selected for undetectable IgE binding in competition assays and for the absence of basophil activation in vitro was unable to induce anaphylaxis in sensitized mice in contrast to rBet v 1. In addition no positive reactivity to AllerT was observed in skin prick tests in human volunteers allergic to birch pollen. In contrast, a second set of COPs, AllerT4-T5 displayed some residual IgE binding in competition ELISA and a weak subliminal reactivity to skin prick testing.CONCLUSIONS: The hypoallergenicity of contiguous overlapping peptides was confirmed by low, if any, IgE binding activity in vitro, by the absence of basophil activation and the absence of in vivo induction of allergic reactions in mouse and human.TRIAL REGISTRATION: ClinicalTrials.gov NCT01719133.
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机译：背景：合成的连续重叠肽（COPs）可能代表过敏原特异性免疫疗法的过敏原提取物或重组过敏原的替代品。结合起来，COP涵盖了整个变应原序列，提供了所有潜在的T细胞表位，同时阻止了天然变应原的IgE构象表位。方法：单个COP源自Bet v 1，桦木花粉的主要变应原及其序列。已知的晶体结构，旨在避免IgE结合。在竞争ELISA和嗜碱性粒细胞脱粒试验中体外测试了三组COP。它们的体内反应性是通过rBet v 1致敏小鼠的腹腔内攻击以及过敏性鼻结膜炎志愿者对桦木花粉的皮肤点刺试验确定的。并且与rBet v 1相比，由于缺乏嗜碱性粒细胞的活化，体外不能在致敏小鼠中引起过敏反应。此外，在对桦木花粉过敏的人类志愿者的皮肤点刺试验中，未观察到对AllerT的阳性反应。相比之下，第二组COPs AllerT4-T5在竞争ELISA中显示出一些残留的IgE结合，并且对皮肤点刺试验的阈下反应性较弱。在体外，由于没有嗜碱性粒细胞激活，也没有在体内诱导小鼠和人类的变态反应。试验注册：ClinicalTrials.gov NCT01719133。
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