A 3D human tissue-engineered lung model to study immune responses to Respiratory Syncytial Virus

呼吸道合胞病毒（RSV）是全球病毒性细支气管炎和肺炎的主要原因，感染 超过70%的孩子在第一年。RSV导致婴儿更频繁和严重的感染 与成年人相比。疫苗的开发一直很复杂，因为宿主的免疫系统 对RSV的应答在疾病发病机制中起重要作用。RSV发病机制的关键可能在于 定义与免疫不成熟时免疫应答缺陷相关的机制。 人类婴儿中肺驻留骨髓细胞对RSV的反应的研究由于RSV感染而受到限制。 缺乏可用的模型。虽然有可能测量气管中存在的细胞因子和趋化因子， 在RSV细支气管炎患者中吸入的RSV，难以获得足够数量的细胞来进行机械治疗， 这些研究可能阐明幼儿先天免疫途径的缺陷。因此，新 需要便于控制感染时间和细胞操作的模型来比较抗RSV 新生儿和成人骨髓细胞的反应。对这些机制的理解可以帮助设计 新的疫苗和疗法。 我们的长期研究目标是使用3D人类组织工程肺模型（3D-HTLM）， 对感染因子的正常免疫反应，以阐明一些病毒和宿主决定因素。 该项目的目标是创建一个3D-HTLM，用于确定 免疫不成熟导致更大的RSV发病机制。肺模型的优点是能够 通过比较幼儿和儿童与成人的反应来测试免疫不成熟的影响 免疫细胞抵抗RSV感染。为了实现这一目标，3D-HTLM将包含与以下相关的细胞类型： 感染和炎症反应，包括血管内皮、呼吸上皮、支持 基质细胞和髓样细胞，既有常驻细胞也有炎症细胞。3D-HTLM包括3D支架， 细胞外基质材料，以允许正确的细胞生理功能和细胞与细胞的相互作用。 我们将追求两个具体目标。目的1：确定3D-HTLM内的肺部微环境是否指示 肺内骨髓细胞的分化。目的2：比较骨髓细胞的天然免疫应答 从新生儿脐带血、幼儿和成人中分离的RSV在3D-HTLM中的感染。 该项目将产生有关免疫反应的新信息，为预防性治疗提供新的靶点。 和RSV感染的治疗性干预，并且组织工程化肺模型也可用于 测试RSV治疗策略。此外，扩大我们关于细胞如何与每个细胞相互作用的知识， 其他人和他们的环境将垂直推进组织工程领域和未来 开发用于肺移植的工程肺，以治疗各种肺部疾病。

Respiratory syncytial virus (RSV) is the leading cause of viral bronchiolitis and pneumonia worldwide, infecting more than 70% of children in the first year. RSV causes more frequent and severe infections in infants compared to adults. The development of vaccines has been complicated by the fact that host immune responses to RSV play a significant role in disease pathogenesis. A key to RSV pathogenesis may lie in defining the mechanisms associated with a deficient immune response at a time of immunological immaturity. The study of the responses of lung-resident myeloid cells to RSV in human infants has been limited due to the lack of available models. While it is possible to measure cytokines and chemokines present in tracheal aspirates in RSV bronchiolitis patients, it is difficult to obtain sufficient numbers of cells to perform mechanistic studies that might elucidate innate immune pathways that are defective in young children. Therefore, new models facilitating control of the timing of infection and cell manipulation are needed to compare the anti-RSV responses of neonatal and adult myeloid cells. An understanding of these mechanisms can aid in the design of new vaccines and therapies. Our long-term research goal is to use a 3D Human Tissue-Engineered Lung Model (3D-HTLM) that exhibits a normal immunological response against infectious agents to elucidate some of the viral and host determinants. The objective of this project is to create a 3D-HTLM that will be used to determine the mechanisms by which immunological immaturity leads to greater RSV pathogenesis. An advantage of the lung model is the ability to test the effect of immunological immaturity by comparing the response of young infants and children vs. adult immune cells to RSV infection. To achieve this goal, the 3D-HTLM will contain the cell types relevant to infection and an inflammatory response, including vascular endothelium, a respiratory epithelium, supporting stromal cells, and myeloid cells, both resident and inflammatory. The 3D-HTLM includes a 3D scaffold and extracellular matrix materials to allow for the correct cell physiological function and cell-to-cell interactions. We will pursue two specific aims. Aim 1: Determine if the lung microenvironment within the 3D-HTLM instructs the differentiation of lung resident myeloid cells. Aim 2: Compare the innate immune response of myeloid cells isolated from neonatal cord blood, young children and adults to RSV infection in the 3D-HTLM. The project will yield new information about the immune response that will provide new targets for preventative and therapeutic interventions of RSV infection, and the tissue-engineered lung model also may be used for testing RSV treatment strategies. In addition, expanding our knowledge about how cells interact with each other and with their environment will vertically advance the field of tissue engineering and the future development of an engineered lung for lung transplantation to treat a variety of lung diseases.