Engineering Hetero-Bivalent Ligands to Inhibit IgE Clustering on Mast Cells

描述(由申请人提供)：工程异二价配体抑制肥大细胞上的IgE聚集项目摘要/摘要过敏是一种免疫系统的紊乱，由变应原介导的免疫球蛋白E(IgE)分子在肥大细胞和嗜碱性粒细胞表面的聚集引起。据估计，多达1200万美国人对食物过敏，1000万人患有过敏性哮喘，1000万人患有特应性湿疹，3600万人 有过敏性鼻炎，而且患病率正在上升。目前的大多数疗法都是用来 治疗过敏相关的不良免疫反应涉及对免疫系统的非特异性抑制。这导致了传染病风险的增加，凸显了有选择地开发有针对性的治疗替代方案的必要性。多价结合作用提供更高的亲和力(称为亲和力)，并导致更强的相互作用。早些时候的研究已经证实，与抗体的情况一样，双价结合可以比单价结合增强相互作用的亲和力六个数量级。在这个拟议的项目中，我们的总体目标是设计异二价配体，以竞争性和选择性地抑制变应原与肥大细胞上的IgE结合，从而抑制IgE聚集和过敏反应。这将通过设计同时针对位于IgE Fab结构域上的两个附近结合部位的异二价分子来实现：抗原结合部位；以及不那么知名的“核苷酸结合部位”。同时与这两个位点的二价结合将为异二价配体提供更强的亲和力和对目标IgE的选择性，并将使竞争抑制变应原与IgE的结合。这些异二价配体将被设计成具有两个部分-抗原分子本身(或模拟表位)和核苷酸结合位点靶向分子-由灵活的连接物分子共价连接。具体地说，我们将：i)确定将针对 这些研究包括：i)设计和合成“半抗原/核苷酸类似物”的异二价配体；iii)测定异二价配体与IgE相互作用的Kd，并评价其对过敏原与IgE结合的抑制作用；iv)确定异二价配体在透明质酸细胞检测中抑制过敏反应的效果。

DESCRIPTION (provided by applicant): Engineering Hetero-Bivalent Ligands to Inhibit IgE Clustering on Mast Cells Project Summary/Abstract Allergy is a disorder of the immune system, which is elicited by the allergen-mediated-clustering of the immunoglobulin E (IgE) molecules on the surface of mast cells and basophils. It is estimated that up to 12 million Americans have food allergies, 10 million suffer from allergic asthma, 10 million suffer atopic eczema, 36 million have allergic rhinitis, and the prevalence is rising. The majority of the current therapies used to treat allergy related adverse immunologic responses involve non-specific suppression of the immune system. This results in the increased risk of infectious diseases, highlighting the need to develop selectively targeting treatment alternatives. Multivalent binding interactions provide higher affinity (termed avidity), and result in stronger interactions. Earlier studies have established that bivalent binding, as in the case of antibodies, can strengthen the avidity of an interaction up by six orders of magnitude over monovalent binding. Our overall goal in this proposed project is to engineer hetero-bivalent ligands that will competitively and selectively inhibit allergen binding to IgEs on mast cells, thereby inhibit IgE clustering and allergic responses. This will be accomplished via designing hetero-bivalent molecules that simultaneously target two nearby binding sites located on the Fab domain of an IgE: the antigen binding site; and the not-so-well-known "nucleotide binding site". Simultaneous bivalent binding to both these sites will provide the hetero-bivalent ligand with enhanced avidity and selectivity for the target IgE, and will enable competitive inhibition of allergen binding to the IgEs. These hetero-bivalent ligands will be designed to have two moieties - the antigenic molecule itself (or the mimotope), and the nucleotide binding site-targeting molecule - covalently linked by a flexible linker molecule. Specifically we will: i) identify nucleotide analogs that will target the unconventional nucleotide binding site on the IgE; ii) design and synthesize hetero-bivalent ligands of 'hapten/nucleotide-analog' conjugates; iii) determination of the Kd for hetero-bivalent ligand - IgE interactions and evaluation of their inhibitory effect on the allergen binding to IgEs and iv) determine the efficacy of the hetero-bivalent ligands to inhibit allergic responses in vitr cellular assays.