Complement Resistance Acquired During Acute to Persistent Rubulavirus Infection

对于许多rna病毒感染来说，最初的急性感染可以转变为长期或持久的 感染，受感染的细胞存活并继续产生后代病毒。补语(C‘)是一个 强大的天然免疫系统，可直接溶解受病毒感染的细胞或中和病毒(1-4)，但 C‘在控制持续呼吸道RNA病毒感染中的作用尚不清楚。考虑到 病毒有阻止C‘介导的细胞裂解的机制，持续感染可以建立长期的 炎症循环-激活的C‘继续提供破坏性炎症，但对病毒有抑制作用 机制阻止了病原体和受感染细胞的清除。 这个项目是从我们惊人的发现中产生的，在人类肺部最初的急性感染期间 与风疹病毒副流感病毒5(PIV5)感染的细胞对C‘介导的反应非常敏感 解体。然而，重要的是，在过渡到持续感染后，感染PIV5的细胞几乎 完全抵抗C‘lysis。我们的转录学数据显示，PIV5急性感染的细胞具有低水平的 C‘抑制因子的水平表达，但这转移到细胞C’抑制因子H的高水平表达， 持续感染细胞中的凝集素、凝集素和凝集素。 我们的中心假设是PIV5持续感染的细胞对C‘介导的 裂解是由于它们获得了表达高水平的C‘抑制因子H和玻璃连蛋白的能力。我们的 目标是确定：1)在PIV5从急性到持续性期间获得C‘抵抗的机制 转变(目标1)，以及2)这种转变对C‘耐药病毒生产的后果(目标2)。 目标1将确定呼吸道细胞对C‘介导的裂解的差异敏感性的机制 在从急性感染向持续性感染过渡期间。工程化呼吸道细胞系及原代培养 气管或支气管气液界面(ALI)细胞培养将被用来检验这一假设 持续感染细胞合成C‘抑制因子H和Vitronectin导致条件化 这些细胞对C‘介导的裂解具有抵抗力。目标2将确定与病毒颗粒相关的C‘因子 来自急性感染细胞和持续感染细胞，并确定了持续病毒对C‘- 中介中和。蛋白质组学和生化分析将检验病毒起源于 持续感染的细胞由于凝血因子H或玻璃凝集素的募集而具有C‘抗性。 我们在C‘与持续RNA病毒感染相互作用方面的工作结果将会有很强的 给治疗提供信息的可能性：1)长期病毒呼吸道感染的临床影响，2) C‘基因的多态可以与病毒感染的严重程度相关，以及3)临床试验 呼吸道感染正在通过调节C‘反应的药物进行。

For many RNA virus infections, an initial acute infection can transition to a prolonged or persistent infection, in which infected cells survive and continue to produce progeny virus. Complement (C’) is a powerful innate immune system which can directly lyse virus-infected cells or neutralize virus (1-4), but the role of C’ in controlling persistent respiratory RNA virus infections is not well understood. Given that viruses have mechanisms to block C’-mediated cell lysis, persistent infections can set up a prolonged inflammation cycle – where activated C’ continues to provide damaging inflammation, but viral inhibitory mechanisms block elimination of pathogen and infected cells. This project emerged from our striking findings that during an initial acute infection of human lung cells with the Rubulavirus Parainfluenza virus 5 (PIV5), infected cells are very sensitive to C’-mediated lysis. Importantly however, after transitioning to a persistent infection, PIV5-infected cells are nearly completely resistant to C’ lysis. Our transcriptomics data show that PIV5 acutely infected cells have low level expression of C’ inhibitors, but this shifts to high level expression of cellular C’ inhibitors Factor H, Factor I, Vitronectin and Clusterin in persistently infected cells. Our central hypothesis is that PIV5 persistently infected cells acquire resistance to C’-mediated lysis due to their acquired ability to express high levels of C’ inhibitors Factor H and Vitronectin. Our goals are to identify: 1) the mechanisms for acquiring C’ resistance during the PIV5 acute-to-persistent transition (Aim 1), and 2) consequences of this shift for production of C’-resistant virus (Aim 2). Aim 1 will define the mechanism for differential sensitivity of airway cells to C’-mediated lysis during transition from acute to persistent infection. Engineered respiratory tract cell lines and primary tracheal or bronchial air-liquid interface (ALI) cell cultures will be used to test the hypothesis that synthesis of C’ inhibitors Factor H and Vitronectin by persistently infected cells results in conditioning of the cells to be resistant to C’-mediated lysis. Aim 2 will identify C’ factors associated with virus particles derived from acute versus persistently infected cells and define the sensitivity of persistent virus to C’- mediated neutralization. Proteomics and biochemical assays will test the hypothesis that virus derived from persistently infected cells will be C’-resistant due to recruitment of Factor H or Vitronectin. Results from our work on C’ interactions with persistent RNA virus infections will have strong potential to inform therapeutics, given: 1) the clinical impact of prolonged viral respiratory infections, 2) polymorphisms in C’ genes can correlate with severity of viral infections, and 3) clinical trials for respiratory tract infections are underway with drugs that modulate C’ responses.