Diffusion of viruses across human airway mucus and trapping by antibodies

病毒通过人体呼吸道粘液扩散并被抗体捕获

• 批准号: 8190616
• 负责人: Samuel Lai
• 金额: $ 18.35万
• 依托单位: UNIV OF NORTH CAROLINA CHAPEL HILL
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-08-01 至 2013-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8190616
• 关键词: Adenoviruses; Adhesions; Adhesives; Aerosols; Affinity; Animals; Antibodies; Aspirate substance; Binding; Biochemical; Blocking Antibodies; Blood; Cells; Clinical; Cystic Fibrosis; Diffuse; Diffusion; Dose; Epithelium; Exhibits; Gel; General Anesthesia; HIV; Herpesviridae; Hour; Human; Human Adenoviruses; Human Papillomavirus; IgG1; Immune system; Immunoglobulin A; Immunoglobulin G; Immunoglobulin M; Infection; Influenza; Intubation; Label; Length; Lung; Lymph; Measures; Mucociliary Clearance; Mucous body substance; Norwalk virus; Obstruction; Operative Surgical Procedures; Patients; Property; Publishing; Resolution; Rhinovirus; Sampling; Simplexvirus; Solid; Speed; Sputum; Surface; Testing; Topical application; Tube; Vaccines; Viral; Virion; Virus; Virus-like particle; Work; antibody engineering; crosslink; endotracheal; experience; healthy volunteer; nanoprobe; nanoscale; neutralizing antibody; novel vaccines; particle; pathogen; prevent; respiratory; respiratory virus; transmission process; viscoelasticity

DESCRIPTION (provided by applicant): To infect lung airways, viruses must penetrate mucus. However, little is known about how or the efficiency with which respiratory viruses can diffuse across airway mucus (AM). In this proposal, using human AM collected from healthy volunteers, we first seek to characterize the mobility of four common respiratory viruses in fresh AM ex vivo, and identify which virus readily penetrates AM and which virus is hindered or trapped. We have developed different sized muco-inert synthetic nanoprobes that reveal the mesh spacing (pore size) and nanoscale viscoelasticity of fresh human mucus secretions. Thus, for viruses that are slowed in AM, we can determine whether the limited mobility is caused by steric occlusion and/or by adhesion to mucus constituents. Recently, we discovered that the mesh spacing in human cervicovaginal mucus is much larger than mammalian viruses, consistent with our earlier observations that HIV, HPV and Norwalk virus all readily diffuse through the same mucus secretions. Hypothesis #1: the mesh spacings in AM are larger than most respiratory viruses, and viruses will readily penetrate AM if they are not slowed by adhesive interactions. Thus, one approach to block pulmonary infections is to adhesively trap viruses in mucus. Numerous studies demonstrate that antibodies (Ab) applied topically to mucosal surfaces, including the lung airways, can provide robust protection against infections, some even at sub-neutralizing concentrations. The immune system secretes more Ab into mucus than blood or lymph, but the mechanisms by which Ab in mucus protect against infections remain poorly studied. Hypothesis #2: Array of virus-bound Ab can form multiple lowaffinity adhesive crosslinks between the virus and the mucus gel. A sufficient number of these low-affinity crosslinks, possibly at sub-neutralizing concentrations, permanently trap viruses in the mucus gel. Trapping reduces flux of virions that can reach target cells, enables rapid elimination via mucociliary clearance, and facilitates viral degradation and inactivation by other protective mechanisms. Our pilot observations indicate that remarkably low concentrations of specific IgG1 can trap HSV and virus-like particles that otherwise rapidly penetrate mucus gels. Aim 1: Measure the transport rates of common respiratory viruses, including adenovirus, influenza, and rhinoviruses, in human AM ex vivo obtained from healthy subjects. We will also characterize the microstructure of AM to determine whether trapped viruses that are immobilized by steric or adhesive interactions. Aim 2: Determine whether virus- specific Ab (IgG, IgA, sIgA, IgM) secreted into native AM may facilitate adhesive trapping of viruses in AM, and investigate whether addition of exogenous virusspecific IgG trap viruses that otherwise rapidly penetrate AM. Together, Aim 1 and 2 will provide a quantitative description of how respiratory viruses may penetrate AM, and how Ab may protect the airways by trapping viruses in AM. The results will likely aid in developing new vaccines or engineering Ab that block infections in the lung airways by trapping virions in AM. PUBLIC HEALTH RELEVANCE: Viruses must penetrate protective mucus coatings to infect mucosal epithelia, but how common respiratory viruses may overcome and penetrate human airway mucus (AM) barrier is unknown. Antibodies (Ab) applied topically to mucosal surfaces often provide robust protection against infections, but the mechanisms by which they do so remain poorly understood. The results in this project will aid in determining the extent to which AM acts as a barrier that reduces infection, whether the barrier properties of AM rely on secreted Ab, and if the AM barrier can be enhanced by induced secretion of (i.e. vaccine) or topically-applied Ab.

描述（由申请人提供）：要感染肺气道，病毒必须穿透粘液。但是，关于呼吸道病毒在气道粘液（AM）中如何散布的效率或效率知之甚少。在此提案中，使用从健康志愿者那里收集的人类AM，我们首先试图表征新鲜AM的四种常见呼吸道病毒的迁移率，并确定哪些病毒易于穿透AM，并且哪些病毒受到阻碍或捕获。我们已经开发了不同尺寸的粘液插入合成纳米探针，这些纳米探针揭示了新鲜人类粘液分泌的网状间距（孔径）和纳米级粘弹性。因此，对于在AM中放慢的病毒，我们可以确定有限的迁移率是否是由空间阻塞和/或对粘液成分的粘附引起的。最近，我们发现人宫颈阴道粘液中的网格间距比哺乳动物病毒大得多，这与我们较早的观察结果一致，即HIV，HPV和Norwalk病毒都很容易通过相同的粘液分泌扩散。假设1：AM中的网格间距比大多数呼吸道病毒大，如果不被粘合剂相互作用减慢，病毒将很容易穿透AM。因此，阻断肺部感染的一种方法是在粘液中粘着诱捕病毒。大量研究表明，局部应用于包括肺气道在内的粘膜表面的抗体（AB）可以为感染提供强大的保护，有些甚至在亚中和浓度下也可以提供。免疫系统比血液或淋巴更多地分泌AB为粘液，但是粘液中AB防止感染的机制仍然很少研究。假设2：结合病毒的AB阵列可以在病毒和粘液凝胶之​​间形成多个低亲和力的交联。这些低亲和力的交联的足够数量可能是在亚中和浓度下，永久将病毒捕获在粘液凝胶中。捕获可减少可以到达靶细胞的病毒体的通量，从而通过粘膜缩减清除快速消除，并促进病毒降解和通过其他保护机制灭活。我们的试点观察结果表明，明显浓度的特定IgG1可能会捕获HSV和类似病毒的颗粒，这些颗粒否则会迅速穿透粘液凝胶。 AIM 1：测量从健康受试者获得的人体外，包括腺病毒，流感和鼻病毒在内的常见呼吸道病毒的转运率。我们还将表征AM的微观结构，以确定是否被空间或粘合剂相互作用固定的捕获的病毒。 AIM 2：确定分泌到天然AM中的病毒特异性AB（IgG，IgA，Siga，IgM）是否可能促进AM中病毒的粘合性捕获，并研究是否添加了外源性Viruss特异性IgG捕获诱捕病毒，而这些病毒是否会迅速穿透AM。 AIM 1和2一起将提供一个定量描述，以描述呼吸病毒如何穿透AM，以及AB如何通过将病毒捕获在AM中来保护气道。结果可能会有助于开发新的疫苗或工程AB，通过将病毒体捕获在AM中，以阻止肺气道中的感染。 公共卫生相关性：病毒必须穿透保护性粘液涂层以感染粘膜上皮，但是常见的呼吸病毒如何克服并穿透人类气道粘液（AM）屏障尚不清楚。局部应用于粘膜表面的抗体（AB）通常可以为感染提供强大的保护，但是它们这样做的机制仍然很熟悉。该项目的结果将有助于确定AM充当降低感染的障碍的程度，是否依赖于分泌的AB，以及是否可以通过诱导的分泌（即疫苗）或局部应用AB来增强AM屏障。