Molecular basis and protective efficacy of cross-neutralizing antibodies against four major respiratory viruses

项目概要/摘要 全世界每年有成千上万的其他致命的癌症被造血干细胞治愈 在肝细胞移植（HCT）中，但不幸的是，超过十分之一的患者将发展为病毒性下呼吸道疾病。 感染，几乎一半的患者死于感染。如果没有完整的免疫系统， 移植后的头几个月，这些危及生命的感染抵消了潜在生命的好处， 拯救移植超过一半的感染是由四种病毒引起的：RSV、HMPV、HPIV 3和HPIV 1， 目前没有任何药物干预用于HCT后的治疗或预防。虽然 成年人在儿童时期普遍感染这些病毒，HCT接受者失去了他们的免疫力， 容易出现严重并发症用单克隆抗体（mAb）进行被动免疫代表了一种免疫应答。 降低这些感染风险的战略。虽然几种抗RSV mAb候选物已经通过 在临床试验中，它们的使用仅限于RSV导致几乎所有肺部感染病例的婴儿。 然而，这些mAb的临床功效预期在HCT患者中显著较低，因为其他的免疫抑制剂可能会抑制HCT患者的免疫应答。 重要的病毒如HMPV、HPIV 3和HPIV 1对疾病有重要作用。为了填补这一临床空白， 在HCT患者中，我们发现了两种交叉中和mAb：一种靶向RSV和HMPV， 另一种靶向HPIV 3和HPIV 1。总之，这些单克隆抗体可以组合在一起，同时保护 针对HCT后导致大多数肺部感染的四种病毒。为了测试疗效，我们将使用这些 mAb对免疫活性和免疫功能低下的动物具有免疫活性和治疗性。我们还将 测试这些单抗的药代动力学，这些单抗具有设计用于增加半衰期和肺功能的修饰， 这意味着单次给药可以提高生物利用度，从而可以跨越移植后的整个脆弱期。另一 在将新的抗体疗法引入临床时，常常被忽视的陷阱是潜在的耐药性。最近 失败的抗RSV单克隆抗体的临床试验表明，逃逸变体的出现可以削弱临床 发展如何在候选人进入临床前阶段之前预测成功或失败 临床试验是一个重要的问题，答案可以节省大量的资源，努力， 时间为了填补这一知识空白，我们开发了一种创新的方法，称为深度突变扫描 这提供了病毒突变景观的全面画面，允许前所未有的临床前研究。 抗性评价。由于本提案中描述的两种交叉中和mAb结合保守的 表位，这些和类似的mAb可能具有高的抗性屏障。为抵抗做好准备 通过未来的病毒变体，我们将利用我们完整的突变图谱的预测来确定下一个- 一代单克隆抗体，使我们能够领先病毒进化几步。这些新型交叉中和mAb 我们开发的创新和严格的审查方法可以提供一个新的标准， 为HCT患者提供护理，并为成功机会最大的其他候选人的设计和测试提供信息。

PROJECT SUMMARY/ABSTRACT Tens of thousands of otherwise deadly cancers are cured worldwide each year by hematopoietic stem cell transplantation (HCT), but unfortunately over one in ten patients will develop a viral lower respiratory tract infection, with almost half of these patients succumbing to the infection. Without an intact immune system in the first few months after transplant, these life-threatening infections offset the benefit derived from potentially life- saving transplant. Over half of these infections are caused by four viruses: RSV, HMPV, HPIV3, and HPIV1, none of which currently have any pharmacologic interventions for treatment or prevention after HCT. Although adults are universally infected with these viruses in childhood, HCT recipients lose their immunity, making them vulnerable to severe complications. Passive immunization with monoclonal antibodies (mAbs) represents a strategy to reduce the risk of these infections. While several anti-RSV mAb candidates have progressed through clinical trials, their use is limited to infants in whom RSV is responsible for virtually all cases of lung infection. However, the clinical efficacy of these mAbs is expected to be substantially lower in HCT patients because other important viruses like HMPV, HPIV3, and HPIV1 contribute significantly to disease. To fill this clinical gap for HCT patients, we have discovered two cross-neutralizing mAbs: one that targets both RSV and HMPV and another that targets both HPIV3 and HPIV1. Together, these mAbs could be combined to simultaneously protect against the four viruses that cause most lung infections after HCT. To test efficacy, we will administer these mAbs prophylactically and therapeutically to immunocompetent and immunocompromised animals. We will also test the pharmacokinetics of these mAbs with modifications designed for increased half-life and lung bioavailability, such that a single dose could bridge the entire period of vulnerability after transplant. Another often neglected pitfall in bringing novel antibody therapies to the bedside is the potential for resistance. Recent failed clinical trials of anti-RSV mAbs have shown that the emergence of escape variants can cripple clinical development. How to predict success or failure during the preclinical phase before candidates progress into clinical trials is an important question, and the answers could save massive amounts of resources, effort, and time. To fill this knowledge gap, we have developed an innovative approach called deep mutational scanning that provides a comprehensive picture of the viral mutational landscape, allowing an unprecedented preclinical evaluation of resistance. Since the two cross-neutralizing mAbs described in this proposal bind to conserved epitopes, these and similar mAbs may have a high barrier of resistance. To prepare for and counter resistance by future viral variants, we will leverage predictions from our complete mutational maps to identify next- generation mAbs, allowing us to stay a few steps ahead of viral evolution. These novel cross-neutralizing mAbs and the innovative and rigorous approaches we have developed to vet them could provide a new standard of care for HCT patients and inform the design and testing of other candidates with the greatest chance for success.