Gain-of-function complement activators as a new class of immunotherapeutic molecules

摘要 补体系统由30多种蛋白质组成，其中大部分是浆蛋白，构成了人类最古老的分支 免疫系统。当被病原体激活时，补体系统放大一个环路，导致 摧毁入侵的有机体。血浆和表面抑制物严格调节补体激活以 防止或限制自我损坏。不幸的是，补体激活因子的功能获得(GOF)突变 在一些罕见的患者中发现的B(FB)会引起永久性的补体激活，从而导致自体炎症。 GoF-FB在激活补体方面更有效，并且对天然补体抑制剂具有抵抗力。给定 这些突变体的活性增强，我们假设我们可以将GOF-FB重定向到特定的恶性肿瘤 用于治疗目的且副作用最小的细胞或组织。在本应用程序中，我们建议生成 以及在体外测试将GOF补体激活蛋白特异性地定向到癌细胞和固体的分子 肿瘤。在目标1中，我们将GOF-FB与单链可变型抗体片段(ScFv)融合，以指导补体 对特定细胞或抗原靶的激活。这种针对免疫治疗的工程化生物方法将 导致嵌合抗原受体T细胞(CAR-T)和BE的更便宜和现成的替代品 与恶性血液病直接相关。这些分子还可以克服一些电流 抗体治疗的问题，包括补体消耗和肿瘤细胞的抑制。在目标2中， 我们将GOF-FB与结合实体肿瘤成分或其微环境的蛋白质偶联。这 该方法将促进实体瘤内和周围区域的炎症，并增强局部免疫反应 最终可以消除肿瘤或解决组织损伤。由于GOF-FB的性质，这些分子 将抵抗肿瘤微环境免疫抑制的机制。在目标3中，我们将生成 小鼠GOF-FB将为将我们的发现转化为动物模型铺平道路，从而允许在体内证明 概念实验、临床前研究以及安全性和有效性评估。我们建议的工作具有很高的 具有创新性，但有确凿的文献证据支持。我们建议在体外证明GOF-FB可以 作为一种潜在的抗癌疗法。这些基于人类补体免疫的新工程分子 疾病可以精确定位一类新的免疫调节剂，其特异性、可及性和活性都高于 目前的治疗方法。它代表了与我们实验室之前进行的研究不同的方向，但 开展拟议工作所需的专业知识和合作者已经到位。此外， FDA批准的一些补体抑制剂用于治疗由GOF突变引起的疾病的有效性 在补体激活方面，确保我们的方法将具有最小的副作用，可以很容易地解决。 这里提出的利用GOF突变来确定新疗法的工作可能会改善对 无数的严重疾病，包括癌症、自身免疫，甚至传染病。

SUMMARY The complement system comprises over 30 proteins, mostly plasmatic, forming the oldest branch of the human immune system. When activated by a pathogen, the complement system amplifies a loop that leads to the destruction of the invading organism. Plasma and surface inhibitors tightly regulate complement activation to prevent or limit self-damage. Unfortunately, gain-of-function (GOF) mutations in the complement activator factor B (FB) found in some rare patients cause permanent complement activation that can lead to autoinflammation. GOF-FB is more efficient at activating complement and is resistant to natural complement inhibitors. Given the enhanced activity of these mutants, we hypothesize that we can redirect GOF-FB to target specific malignant cells or tissues for therapeutic purposes and with minimal side effects. In this application, we propose generating and testing in vitro molecules to direct GOF complement activating proteins specifically to cancer cells and solid tumors. In Aim 1, we will fuse GOF-FB to single-chain variable antibody fragments (scFV) to direct complement activation to specific cells or antigenic targets. This engineered biologic approach to target immunotherapy will lead to less expensive and off-the-shelf alternatives to chimeric antigen receptor T cells (CAR-T) and be immediately relevant for hematologic malignancies. These molecules could also overcome some of the current issues with antibody therapies, including complement consumption and inhibition by the tumor cells. In Aim 2, we will couple GOF-FB to proteins that bind components of the solid tumor or its microenvironment. This approach will promote inflammation in regions in and around solid tumors and enhance local immune responses that can ultimately eliminate tumors or resolve tissue damage. Due to the nature of GOF-FB, these molecules will be resistant to tumor microenvironmental immune suppression mechanisms. In aim 3, we will generate murine GOF-FB that will pave the way to translate our findings to animal models allowing for in vivo proof of concept experiments, preclinical studies, and assessments of safety and efficacy. Our proposed work is highly innovative and yet supported by solid literature evidence. We propose to prove in vitro that GOF-FB can have potential as an anti-cancer therapy. These newly engineered molecules based on human complement immune disorders could pinpoint a new class of immune modulators with greater specificity, reach, and activity than current treatments. It represents a different direction from previous research performed in our lab, but the expertise required to carry out the proposed work and the collaborators are already in place. Furthermore, the proven efficacy of some FDA-approved complement inhibitors used to treat diseases caused by GOF mutations in complement activation assures that our approach will have minimal side effects that can be readily addressed. The work proposed here to leverage GOF mutations to identify new therapies could improve the treatment of a myriad of severe diseases, including cancer, autoimmunity, and even infectious diseases.