Engineered “muco-trapping” antibodies for inhaled therapy of parainfluenza and human metapneumovirus infections

人类副流感病毒(PIV)和偏肺炎病毒(MPV)是引起下呼吸道疾病的常见原因 婴幼儿呼吸道感染，主要原因是呼吸道疾病免疫受损 成年人和老年人。不幸的是，这两种病毒都没有治疗方法或疫苗，只有支持性的 我们提供医疗服务。有趣的是，PIV和MPV有许多共同的病理和临床表现 呼吸道合胞病毒(RSV)。事实上，PIV和MPV都不会导致血液中的病毒血症。 感染的患者，表明这两种感染都严格局限于呼吸道内，类似于排出后代的RSV 病毒仅来自受感染细胞的顶端表面。这种独特的病理生理学意味着后代 病毒在传播到邻近细胞之前必须穿过呼吸道粘液(AM)。这反过来又激励我们 开发一种病原体特异性抗病毒药物，可以在物理上限制感染在呼吸道内的传播。 我们最近发现了一种新的抗体效应器功能，用于捕获粘液中的单个病原体 基于精心调整的Ig G-Fc和粘蛋白之间的亲和力-并开发了增强mAb的平台 在粘膜表面起作用。我们推测，送到呼吸道的“粘液捕捉型”单抗可以直接 通过截获和捕获AM中的脱落后代病毒来干预病毒的生命周期，迅速消除 通过自然的粘液纤毛清除从呼吸道捕获病毒，并在体内进行有效的治疗。在……里面 在这一策略的支持下，我们设计了能够有效捕获AM中RSV的单抗，并显示出雾化 有效地从感染后第3天开始向感染RSV的新生羔羊交付“粘液捕捉型”单抗 在3天内将肺组织中的传染性病毒载量降低到无法检测到的水平，并在 与赋形剂对照组相比，支气管组织减少了11倍。这些结果激发了我们探索 类似的方法在治疗PIV和MPV感染方面是否有效。为了支持这一应用程序， 我们已经设计出对这两种病毒不同毒株具有皮摩尔亲和力的抗体，并证明了 我们可以有效地捕获人类AM中的病毒，并限制体外感染在分化良好的人中的传播 在气液界面生长的呼吸道上皮(WD-HAE)。 在这项提案中，我们将继续使用哺乳动物和酵母展示进行亲和力成熟的工作 生产高亲和力单抗，广泛结合和中和不同的PIV和MPV毒株(目标1)。我们会 验证这些单抗是否能捕获新鲜未稀释的人AM中的PIV和MPV，以及它们是否能抑制 预先确定的PIV和MPV感染在WD-HAE培养物中的传播(目标2)。然后，我们将提前 在仓鼠鼻部感染模型中用于评估这两种病毒的先导mAb(目标3)。通过启用增强版 单抗在粘液分泌物中的功能，我们希望我们将有助于为改进分子靶向铺平道路 针对所有主要粘膜表面的广泛病原体的治疗和预防，提供 一个强有力的选择，解决了目前在呼吸道感染的药物干预方面的空白。

Human parainfluenza virus (PIV) and metapneumovirus (MPV) are common causes of lower respiratory tract infections in infants and young children, and major causes of respiratory illness in immune compromised adults and the elderly. Unfortunately, there are no therapy or vaccine for either viruses, and only supportive medical care is available. Interestingly, PIV and MPV share many pathological and clinical manifestations as Respiratory Syncytial Virus (RSV). Indeed, neither PIV nor MPV are known to cause viremia in the blood of infected patients, indicating both infections are strictly localized in the airways similar to RSV that shed progeny viruses exclusively from the apical surface of infected cells. Such unique pathophysiology implies progeny viruses must traverse airway mucus (AM) before spreading to neighboring cells. This in turn motivated us to develop a pathogen-specific antiviral that could physically limit the spread of the infections within the airways. We recently discovered a novel Ab effector function in mucus – trapping individual pathogens in mucus based on carefully-tuned affinity between IgG-Fc and mucins – and developed a platform for enhancing mAb function at mucosal surfaces. We hypothesize that “muco-trapping” mAb delivered to the airways can directly intervene with the viral life cycle by intercepting and trapping shed progeny viruses in AM, rapidly eliminate trapped viruses from the airways by natural mucociliary clearance, and enable effective therapy in vivo. In support of this strategy, we engineered mAbs that potently trap RSV in AM, and showed that nebulized delivery of “muco-trapping” mAb to RSV-infected neonatal lambs beginning on Day 3 post infection effectively reduced the infectious viral load in lung tissues to non-detectible levels within 3 days, with viral RNA in bronchial tissues reduced by 11-fold compared to vehicle control. These results motivated us to explore whether a similar approach may be effective in treating PIV and MPV infections. In support of this application, we have engineered antibodies with picomolar affinity to diverse strains of both viruses, and demonstrated that we could effectively trap viruses in human AM and limit spread of infection in vitro in well-differentiated human airway epithelium (WD-HAE) grown at the air-liquid interface. In this proposal, we will continue our work with affinity maturation using mammalian and yeast display to produce high affinity mAb that broadly bind and neutralize diverse strains of PIV and MPV (Aim 1). We will validate whether these mAbs can trap PIV and MPV in fresh undiluted human AM, and whether they can inhibit the spread of pre-established PIV and MPV infections in WD-HAE cultures (Aim 2). We will then advance the lead mAb for both viruses for evaluation in a hamster nasal infection model (Aim 3). By enabling enhanced mAb function in mucus secretions, we expect we will help pave the way for improved, molecularly-targeted therapies and prophylaxis against a broad spectrum of pathogens across all major mucosal surfaces, providing a powerful option addressing the current gap in pharmacological interventions for respiratory infections.