Collectin-Mediated Defense Against Influenza

甲型流感病毒（IAV）是一种主要的威胁，因为它通过遗传变异逃避适应性免疫。 包括表面活性蛋白D（SP-D）在内的先天性防御在IAV感染的早期阶段至关重要。我们的核心 有一种假说认为SP-D直接抑制IAV的感染性，并减少IAV感染过程中的炎症反应 通过影响呼吸道上皮和多形核中性粒细胞（PMN）感染。我们的目标是 确定这些影响是如何关联的，哪些是最重要的。目标1将研究SP-D如何调节 体外和体内呼吸道上皮感染。我们将利用抗SP-D和敏感的IAV 株和条件性SP-D基因缺失（SP-D -/-）小鼠，以阐明SP-D如何抑制IAV复制， 这与SP-D减少炎症反应的关系。IAV感染的体外研究 呼吸道上皮细胞将详细确定SP-D如何调节病毒生命周期和细胞信号传导。 目的2将利用一组重组修饰形式的SP-D来确定哪种分子 SP-D的特性对于抗病毒和抗炎活性是至关重要的。这些重组SP-D变体 将在体外（在人呼吸道细胞培养物中）和体内使用滴注和遗传拯救进行测试 以纠正条件性SP-D -/-小鼠抗病毒应答的异常。我们的假设是 SP-D的多聚化和糖结合性质在决定其抗病毒和抗肿瘤活性方面都是重要的。 抗炎作用，并且该结构将有助于分离这些效应。目标3将决定 在IAV感染期间SP-D如何下调PMN流入以及PMN对肺损伤的贡献， 控制体内病毒复制。对人中性粒细胞的体外研究将确定SP-D如何调节 IAV被PMN摄取以及SP-D如何调节IAV感染的PMN的呼吸爆发反应。SP-D 可以增加或减少体外IAV处理的PMN的呼吸爆发反应，这取决于 将SP-D和IAV加入细胞的顺序。中性粒细胞对IAV和SP-D的特异性受体在白血病中的作用 将对这些影响进行评估。目的4将评估另外两种具有抗病毒作用的先天免疫蛋白质， 它们自身具有活性，而且还结合并改变SP-D的功能。这些富含清道夫受体 糖蛋白340（gp 340）和人嗜中性粒细胞防御素（HNP）。这些研究应该阐明 重要方面的防御抗IAV和相关的治疗和预防策略。

Influenza A virus (IAV) is a major threat due to evasion of adaptive immunity through genetic variation. Innate defenses, including surfactant protein D (SP-D) are critical in the early phase IAV infection. Our core hypothesis is that SP-D inhibits IAV infectivity directly and also reduces inflammatory responses during IAV infection through effects on respiratory epithelium and polymorphonuclear neutrophils (PMNs). We aim to determine how these effects relate and which is most important. Aim 1 will examine how SP-D modulates infection of respiratory epithelium in vitro and in vivo. We will make use of SP-D-resistant and -senstive IAV strains and conditionally SP-D gene-deleted (SP-D -/-) mice to clarify how SP-D inhibits IAV replication and how this relates to reduction of inflammatory responses by SP-D. In vitro studies of IAV infection in respiratory epithelial cells will determine in detail how SP-D modulates the viral life cycle and cell signaling. Aim 2 will make use of a panel of recombinantly modified forms of SP-D to determine which molecular features of SP-D are critical for antiviral and anti-inflammatory activities. These recombinant SP-D variants will be tested both in vitro (in human respiratory cell culture) and in vivo using instillation and genetic rescue to correct abnormalities in the antiviral response of conditional SP-D -/- mice. Our hypothesis is that multimerzation and saccharide binding properties of SP-D are both important in determing its antiviral and anti-inflammatory effects, and that the constructs will help separate out these efects. Aim 3 will determine how SP-D downregulates PMN influx during IAV infection and the contribution of PMNs to lung injury or control of viral replication in vivo. In vitro studies with human PMNs will determine how SP-D modulates the uptake of IAV by PMNs and how SP-D modulates respiratory burst responses of lAV-infected PMNs. SP-D can eitehr increase or reduce respiratory burst responses of lAV-treated PMNs in vitro depending on sequence of addition of SP-D and IAV to the cells. The role of specific PMN receptors for IAV and SP-D in these effects will be evaluated. Aim 4 will evaluate two other innate immune proteins that have antiviral activity in their own right but also bind to, and modify function of SP-D. These are scavenger receptor rich glycoprotein 340 (gp340) and human neutronphil defensins (HNPs). These studies should elucidate important aspectsof defense against IAV and be relevant to treatment and prevention strategies.