Targeting EndoS to auto-antibodies

自身抗体，其识别自身抗原（即，自身抗原），作为标志和诊断 自身免疫性疾病的标志物。虽然自身免疫性疾病的机制是复杂的，并涉及各种 体液和细胞免疫应答中，有些完全依赖于自身抗体的存在。 自身反应性抗体与其同源自身抗原结合后，诱导免疫效应机制 通过补体激活和/或Fc受体结合。产生的自身抗体介导的效应物 这些机制导致慢性炎症和自身免疫性疾病的最终组织损伤症状。 由IgG抗体介导的效应子功能，无论它们识别自身抗原还是外来抗原，都完全是由抗体介导的。 依赖于IgG Fc区的Asn 297上N-连接的复合型聚糖的存在，这使得 抗体结合Fc γ受体（FcγRs）并激活补体，赋予抗体免疫原性， 信号能力。内切糖苷酶（即，从糖蛋白中除去聚糖的酶）可以除去 聚糖分子与Asn 297连接，并使IgG抗体免疫惰性。已知所有 内切糖苷酶，内切糖苷酶S（EndoS）是独特的，因为它仅从酶中去除Asn 297连接的聚糖。 IgG抗体。由于其IgG特异性性质，病理性自身抗体和/或 在自身免疫的动物模型中注射纯化的EndoS已经显示出保护或减轻免疫缺陷。 许多自身免疫性疾病的症状。虽然EndoS对IgG抗体具有特异性，但它没有 区分不同抗原特异性抗体的能力。相反，EndoS去糖基化 所有IgG抗体，包括那些控制癌症的抗体，以及那些对外来抗原特异的抗体 提供抵抗感染的能力。工程化EndoS，使其仅识别和去糖基化 与所有IgG抗体相反，自身抗体对于制备真正特异性的自身免疫药物至关重要。我们 假设我们可以将EndoS从一种具有巨大潜力的自身免疫性疾病治疗剂转化为 通过构建与自身抗原连接的EndoS融合蛋白（EndoS-autoAg）， 驱动病理性自身抗体的靶向去糖基化和失活，同时留下剩余的 免疫系统功能完好我们将通过以下方式为这一概念提供原理证明：（1）优化 EndoS-autoAg融合蛋白的体外特异性和活性特性;（2）研究EndoS-autoAg 融合蛋白在获得性自身免疫性大疱性表皮病小鼠模型中的体内功效和特异性 （EBA）。

Autoantibodies, which recognize autoantigens (i.e., self-antigens), serve as both hallmarks and diagnostic markers of autoimmune diseases. Although autoimmune disease mechanisms are complex and involve various humoral and cellular immune responses, some are exclusively dependent on the presence of autoantibodies. Upon binding to their cognate autoantigens, self-reactive antibodies induce effector mechanisms of immunity through complement activation and/or Fc receptor binding. The resulting autoantibody-mediated effector mechanisms lead to chronic inflammation and the eventual tissue damage symptomatic of autoimmune disease. The effector functions mediated by IgG antibodies, whether they recognize self or foreign antigens, are entirely dependent on the presence of an N-linked complex type glycan on Asn297 of the IgG Fc region, which enables the antibody to bind Fc γ receptors (FcγRs) and activate complement, endowing the antibody with immune signaling capabilities. Endoglycosidases (i.e., enzymes that remove glycans from glycoproteins) can remove the glycan molecule linked to Asn297 and render IgG antibodies immunologically inert. Of all the known endoglycosidases, Endoglycosidase S (EndoS) is unique in that it removes only the Asn297-linked glycan from IgG antibodies. Due to its IgG-specific properties, EndoS pretreatment of pathological autoantibodies and/or injection of purified EndoS in animal models of autoimmunity has been shown to protect against or alleviate the symptoms of many autoimmune diseases. Although EndoS is exquisitely specific to IgG antibodies, it has no capacity to discriminate between antibodies with different antigen specificities. Instead, EndoS deglycosylates all IgG antibodies, including those that keep cancer in check, as well as those that are specific to foreign antigens that provide defense from infections. Engineering EndoS such that it recognizes and deglycosylates only autoantibodies, as opposed to all IgG antibodies, is essential for making a truly specific autoimmunity drug. We hypothesize that we can translate EndoS from an autoimmune disease therapeutic of great potential to one of actual clinical utility by constructing fusion proteins of EndoS linked to autoantigens (EndoS-autoAg) that will drive the targeted deglycosylation and inactivation of pathological autoantibodies, while leaving the remainder of the immune system functionally intact. We will provide proof-of-principle for this concept by: (1) optimizing EndoS-autoAg fusion protein properties for specificity and activity in vitro; and (2) investigating EndoS-autoAg fusion protein efficacy and specificity in vivo using a mouse model of autoimmune epidermolysis bullosa acquisita (EBA).