BPIFA1: from anti-viral peptide to immunomodulator

季节性流感是呼吸道感染的一个主要原因，在全世界造成大量发病率、死亡率和经济负担。大流行性流感零星出现，是一个重大的全球卫生问题。有疫苗和抗病毒药物可以对抗流感。然而，由于病毒的快速进化，疫苗需要每年重新配制和重新施用，并带来相关的经济成本。例如，英国为准备和应对2009年的大流行花费了12.4亿英镑。因此，了解宿主机制如何调节流感病毒感染以及如何利用这些机制开发新的治疗干预措施是很重要的。这对老年人尤其重要，因为老年人对流感疫苗的应答减少，意味着每年接种流感疫苗的效果较差。气道上皮在防御病原体方面起着重要作用，并分泌在先天免疫和适应性免疫中起作用的蛋白质/肽。BPIFA1是一种分泌到气道中的蛋白质。监督小组（病毒学家、呼吸生物学家和免疫学家）合作表明，BPIFA1是一种抗病毒肽，限制甲型流感病毒感染细胞（Mucosal Immunology，提前出版在线）。DOI: 10.1038 / mi.2017.45)。此外，BPIFA1促进对流感感染的抗体反应，从而防止再次感染。预防流感疫苗依赖于产生高滴度抗体。结合体外和体内方法，我们将确定BPIFA1是否可以增强抗体对流感疫苗的反应（作为佐剂），从而提高对传播和严重临床疾病的保护。有3个具体目标：1。BPIFA1能增加对甲型流感病毒的抗体反应吗？重组BPIFA1将与小鼠流感疫苗一起使用，以测量抗流感抗体和T细胞反应的增加以及对感染/传播的增强保护。与我们的工业合作伙伴一起，BPIFA1和/或疫苗将与ProSilic给药技术结合，看看控释是否能提高疗效。多种流感病毒株将用于评估对异源病毒株的保护作用。我们还将进行病理分析，看看给药BPIFA1是否对小鼠在攻击前后的不良病理有任何影响。2. BPIFA1的作用是否随年龄或疾病易感性而改变？为了解决这个问题，我们将使用人类鼻咽吸入样本，按年龄分层，以确定BPIFA1水平是否随着年龄的增长而下降，以及它是否与疾病易感性相关。这将在年轻和年老的老鼠身上得到重复。我们还将确定BPIFA1是否能像上述目的1那样，积极地增强老年小鼠对甲型流感的疫苗反应。3. BPIFA1是否会改变抗原提呈细胞的摄取？为了了解其机制，我们将使用体外三维气液界面培养方法模拟人类气道。我们将在这些细胞中加入树突细胞，用流感病毒感染，观察在BPIFA1基因敲除前后以及使用或不使用ProSilic时病毒的摄取情况。我们还将研究吸收病毒的树突状细胞的表型，以及BPIFA1是否可以增强流感蛋白向CD4和CD8 T细胞的呈递。这些结果将显著增强我们对病毒防御的理解，IAV感染期间的炎症反应，并为新疫苗的产生提供信息。

Seasonal influenza is a major cause of respiratory infection resulting in substantial morbidity, mortality and economic burden worldwide. Pandemic influenza emerges sporadically and are a substantial global health concern. There are vaccines and antiviral drugs to combat influenza. However, due to rapid virus evolution, vaccines need to be re-formulated and re-administered annually with associated economic cost. For instance, the UK spent £1.24 billion preparing for and responding to the 2009 pandemic. It is therefore important to understand how host mechanisms modulate influenza virus infection and how these may be used to develop novel therapeutic interventions. This is particularly important in the elderly, where a decreased response means annual influenza vaccination is less effective in this age-group The airway epithelium has a fundamental role in the defense against pathogens and secretes proteins/peptides that function in innate and adaptive immunity. BPIFA1 is a protein that is secreted into the airways. The supervisory team (virologist, respiratory biologist and immunologist) in collaboration has shown that BPIFA1 is an anti-viral peptide, restricting influenza A virus infection of cells (Mucosal Immunology, Published online in advance of print. DOI:10.1038/mi.2017.45). Also, BPIFA1 promotes the antibody response to influenza infection and therefore protection from re-infection. Vaccination against influenza relies upon the generation of high titre antibodies. Combining in vitro and in vivo approaches we will determine whether BPIFA1 can enhance (act as an adjuvant to) the antibody response to influenza vaccination and so improve protection to transmission and severe clinical disease. There are 3 specific aims: 1. Can BPIFA1 increase the antibody response to influenza A virus? Recombinant BPIFA1 will be used with influenza vaccines in mice to measure increases in anti-influenza antibody and T cell responses and increased protection against infection/transmission. With our industrial partner, BPIFA1 and/or vaccine will be combined with ProSilic drug delivery technology to see if controlled release enhances the efficacy. Multiple strains of influenza virus will be used to assess protection against heterologous virus strains. We will also perform pathological analyses to see whether administration of BPIFA1 has any consequences in terms of adverse pathology on the mice before and after challenge. 2. Does the effect of BPIFA1 alter with ageing or predispose to disease. To address this, we will use human nasopharyngeal aspirate samples, stratified by age to determine if the level of BPIFA1 decreases with age and whether it correlates with susceptibility to disease. This will be replicated in young and aged mice. We will also determine if BPIFA1 can positively enhance vaccine responses to influenza A in aged mice as in aim 1 above. 3. Does BPIFA1 alter the uptake by antigen-presenting cells To understand mechanism, we will model the human airway using in vitro 3D air-liquid interface cultures. We will add dendritic cells to these, infect with influenza and look at the uptake of virus before and after the knockdown of BPIFA1 and with or without the use of ProSilic. We will also examine the phenotype of dendritic cells that take up virus, and whether BPIFA1 can enhance presentation of influenza proteins to CD4 and CD8 T cells The results will significantly enhance our understanding of anti-viral defence, the inflammatory response during IAV infection and inform the generation of novel vaccines.