Targeting surface-bound IgE as a novel allergy therapeutic

描述（由申请人提供）：该SBIR申请的总体目标是开发和商业化下一代过敏生物疗法。这种新型治疗药物是一种抗IgE单克隆半抗体，靶向过敏效应细胞上的表面结合IgE，并在功能上阻断过敏反应。过敏性疾病已经增加到这样的程度，它们现在已经成为一个主要的全球公共卫生问题，特别是在发达国家，如美国。过敏症的新型有效治疗选择仍然是一个主要的未满足的需求;没有有效的治疗方法可用于严重的食物过敏，如花生过敏，自2003年基于Xolair（r）的抗IgE治疗以来，没有新的吸入性过敏平台获得许可。在此应用中，我们提出了一种新的方法，基因工程抗？mAb半分子[AEHM] E-3.56用于阻断过敏反应性。这种治疗的基本原理 方法是基于我们的初步发现，这种AEHM的Fc？RI结合过敏效应细胞上的IgE不能介导交联并触发细胞的免疫反应。 其单价性质，同时，其结合抑制随后的过敏原诱导的反应性。因此，本申请的主要目的是产生基因工程改造的原型AEHM E-3.56，并通过实验证明E-3.56与过敏效应细胞上的表面结合IgE的结合作为抗过敏反应性的新治疗剂发挥作用。在目的1，我们将工程师和表达的原型IgG 1抗IgE（IgE）半抗体分子E-3.56组成的小鼠VH和VL区连接到人？1重链和？轻链恒定区分别与两个关键的半胱氨酸在C？1铰链区突变以防止两个CH链的二聚化。通过瞬时转染或通过建立的稳定细胞系共表达嵌合H和L链将导致产生E-3.56，其对于人IgE结合是单价的。在目标2中，我们将测试E-3.56在体外和体内建立的过敏模型中抑制过敏反应的能力的安全性特征和治疗功效。我们将使用全身过敏性过敏反应模型，被动皮肤过敏反应模型和人嗜碱性粒细胞刺激来测试E-3.56的安全性和治疗效果。在目的3中，我们将确定E-3.56通过以下机制中的哪一种抑制过敏反应性：1）空间障碍，防止进入过敏原结合位点; 2）触发效应肥大细胞和嗜碱性粒细胞中的负信号传导; 3）促进细胞表面IgE- Fc的清除？RI络合物; 4）触发IgE的过敏原结合位点的构象变化，导致过敏原结合的丧失;和/或5）干扰过敏性信号传导所必需的IgE交联。本申请旨在开发与公众健康相关的新型过敏治疗剂。

DESCRIPTION (provided by applicant): The overall goal of this SBIR application is to develop and commercialize a next generation allergy biologic therapy. This novel therapeutic, an anti-IgE monoclonal half antibody, targets the surface-bound IgE on allergic effector cells and functionally blocks allergic reactivity. Allergic disorders have increased to the point where they have now become a major worldwide public health issue and particularly so in developed countries such as the US. Novel effective treatment options for allergies remain a major unmet need; no effective therapy is available for severe food allergies such as peanut allergy and no new platforms for inhalant allergy have been licensed since Xolair(r)-based anti-IgE therapy in 2003. In this application we propose a new approach where a genetically engineered anti-? mAb half molecule [AEHM] E-3.56 is used to block allergic reactivity. The rationale of this therapeutic approach is based on our preliminary finding that binding of this AEHM to the Fc?RI bound IgE on allergic effector cells is incapable of mediating the cross-linking and triggering the cells due to its monovalent nature while at the same time, its binding inhibits subsequent allergen-induced reactivity. Thus the primary objective of this application is to produce a genetically engineered prototype AEHM E-3.56 and experimentally show that E-3.56 binding to surface-bound IgE on the allergic effector cells functions as a novel therapeutic against allergic reactivity. In Aim 1,we will engineer and express a prototypic IgG1 anti-epsilon (IgE) half antibody molecule E-3.56 composed of the mouse VH and VL regions linked to the human ?1 heavy chain and ? light chain constant regions respectively, with the two key cysteines in the C?1 hinge region mutated to preventing dimerization of the two CH chains. Co-expression of the chimeric H and L chains either by transient transfection or via established stable cell lines will result in the productionof E-3.56 that is monovalent for human IgE binding. In Aim 2, we will test the safety profile and therapeutic efficacy of E-3.56 for its ability to inhibit allergic responses in in vitro and in viv established allergy models. We will use a systemic allergic anaphylaxis model, passive cutaneous anaphylaxis model and human basophil stimulation to test an E-3.56's safety and therapeutic efficacy. In Aim 3 we will define by which of the following mechanisms E-3.56 suppresses allergic reactivity: 1) Steric hindrance preventing access to the allergen binding sites; 2) Triggering negative signaling in effector mast cells and basophils; 3) Promoting clearance of cell surface IgE- Fc?RI complexes; 4) Triggering conformational change of IgE's allergen-binding sites leading to loss of allergen binding; and/or 5) Interfering with the IgE cros-linking necessary for allergic signaling. This application is directed at the development of a nove allergy therapeutic that is relevant to the public health.