背景:阻断主要的猫过敏原,Feld1,单克隆抗体可有效预防急性猫过敏反应。
目的:这项研究试图扩展过敏原特异性抗体方法,并证明针对桦树花粉中免疫显性和最丰富的变应原蛋白Betv1的单克隆抗体组合,可以防止桦树的过敏反应。
方法:Betv1-specificmAb,使用VelocImmune平台分离REGN5713、REGN5714和REGN5715。表面等离子体共振,x射线晶体学,和低温电子显微镜确定结合动力学和结构数据。抑制IgE结合,嗜碱性粒细胞激活,通过阻断ELISA评估肥大细胞脱颗粒,流式细胞术,和被动皮肤过敏反应小鼠模型。
结果:REGN5713、REGN5714和REGN5715以高亲和力和非竞争性结合Betv1。三种抗体的混合物,REGN5713/14/15,阻断IgE与Betv1的结合,并抑制Betv1-和桦树花粉提取物诱导的嗜碱性粒细胞体外活化和体内肥大细胞脱颗粒。Betv1与REGN5713或REGN5715的免疫球蛋白抗原结合片段的复合物的晶体结构在Betv1上显示出不同的相互作用位点。低温电子显微镜显示由REGN5713/14/15与Betv1结合形成的平面且大致对称的复合物。
结论:这些数据证实了Betv1在桦树变态反应中的免疫优势,并证明了REGN5713/14/15对桦树变态反应的阻断。结构分析显示REGN5713、REGN5714和REGN5715与Betv1暴露的大量区域同时结合,这表明靶向特定表位足以阻断过敏反应。
Blocking the major cat allergen, Fel d 1, with mAbs was effective in preventing an acute cat allergic response.
This study sought to extend the allergen-specific antibody approach and demonstrate that a combination of mAbs targeting Bet v 1, the immunodominant and most abundant allergenic protein in birch pollen, can prevent the birch allergic response.
Bet v 1-specific mAbs, REGN5713, REGN5714, and REGN5715, were isolated using the VelocImmune platform. Surface plasmon resonance, x-ray crystallography, and cryo-electron microscopy determined binding kinetics and structural data. Inhibition of IgE-binding, basophil activation, and mast cell degranulation were assessed via blocking ELISA, flow cytometry, and the passive cutaneous anaphylaxis mouse model.
REGN5713, REGN5714, and REGN5715 bind with high affinity and noncompetitively to Bet v 1. A cocktail of all 3 antibodies, REGN5713/14/15, blocks IgE binding to Bet v 1 and inhibits Bet v 1- and birch pollen extract-induced basophil activation ex vivo and mast cell degranulation in vivo. Crystal structures of the complex of Bet v 1 with immunoglobulin antigen-binding fragments of REGN5713 or REGN5715 show distinct interaction sites on Bet v 1. Cryo-electron microscopy reveals a planar and roughly symmetrical complex formed by REGN5713/14/15 bound to Bet v 1.
These data confirm the immunodominance of Bet v 1 in birch allergy and demonstrate blockade of the birch allergic response with REGN5713/14/15. Structural analyses show simultaneous binding of REGN5713, REGN5714, and REGN5715 with substantial areas of Bet v 1 exposed, suggesting that targeting specific epitopes is sufficient to block the allergic response.