Immunogenetics of antiviral immunity in ducks

我的NSERC研究项目专注于野鸭种群的免疫遗传学及其对它们作为流感宿主的作用的影响。我们知道，加拿大湖泊中随时有15%-30%的野鸭感染流感。我们想知道鸭子是如何清除病毒的，并能够将鸭子的基因与它们的疾病易感性/抵抗力联系起来。了解这一点对于养殖抗性鸭子以及旨在维持生态系统中健康的野鸭种群和狩猎的保护工作都是有用的。免疫反应的三个手臂参与清除病毒；抗体，涉及杀死受感染细胞的白细胞的获得性免疫，以及先天免疫。我们认为，适应性免疫受损是它们被开发为大多数流感病毒株宿主的原因，而天然免疫使它们能够在高致病性禽流感中存活。我们的长期目标是从免疫学的角度了解这些宿主-病原体的相互作用，并了解遗传多样性在宿主免疫反应中的作用。控制宿主免疫反应的基因位于主要组织相容性复合体的一条染色体上。这些基因在物种中的多样性决定了它们对抗病毒病原体的成功。我们正在探索控制三种白细胞、辅助和细胞毒性T细胞以及自然杀伤细胞的基因的多样性。我们采集了50只野生绿头鸭的血液样本，并用这些样本检测了MHC I类基因的多样性，这种基因允许将病毒多肽呈递给细胞毒性T细胞。我们的数据显示，鸭子在种群中具有很大的多样性，但个体只使用一个基因，而人类使用3个基因。由这一基因制造的蛋白质可以呈现数量少得多的病毒蛋白质来进行检测。这可能会限制鸭子看到受流感感染的细胞的能力，并有助于解释为什么鸭子是流感的宿主。我们试图理解的一个难题是，这些基因的表达对于适应性免疫来说还为时过早。我们知道这些蛋白质(在人类中)也参与NK细胞的识别，也许这就是它们这么早表达的原因。NK细胞是病毒感染的第一反应细胞。为了了解NK细胞在鸭子中的工作原理，我们将从50只鸭子中鉴定NK细胞受体。再一次，我们预计这些在不同的个体之间是不同的，其中一些可能在控制NK细胞杀伤方面更好。我们的研究将有助于理解流感病毒如何利用鸭子作为宿主和宿主。虽然我们主要关注野鸭，但这项工作可以为抗流感鸭子的培育和选择以及野生自然种群的保护提供信息。

My NSERC research program is focused on the immunogenetics of the wild duck population and its influence on their role as host of influenza. We know that 15-30% of wild ducks are infected with influenza in Canadian lakes at any time. We would like to know how ducks clear the virus, and be able to correlate the genetics of ducks with their disease susceptibility/resistance. This would be useful to know for farming resistant ducks, as well as conservation efforts aimed at maintaining a healthy population of wild ducks in the ecosystem, and for hunting. Three arms of the immune response are involved in clearing viruses; antibodies, adaptive immunity involving white blood cells that kill infected cells, and innate immunity. We believe that impaired adaptive immunity is responsible for their exploitation as the host of most strains of influenza, while innate immunity allows them to survive highly pathogenic avian influenza. Our long-term goal is to understand these host-pathogen interactions from an immunology perspective, and understand the role of genetic diversity in host immune responses. The genes that control the host immune response are located on one chromosome in the Major Histocompatibility Complex. The diversity of these genes in the species determines their success against viral pathogens. We are exploring the diversity of genes that control three kinds of white blood cells, the helper and cytotoxic T cells and the Natural Killer cells. We have blood samples from 50 wild mallard ducks and we have used these to examine diversity of the genes for MHC class I that allow presentation of viral peptides to cytotoxic T cells. Our data show that ducks have a lot of diversity in the population, but individuals use only one gene while humans use 3 genes. The proteins made by this one gene can present a much smaller number of viral proteins to enable detection. This is likely to limit the ability of ducks to see influenza infected cells, and contributes to why ducks are the host of influenza. One puzzle we are trying to understand is that the expression of these genes is too early for adaptive immunity. We know these proteins (in humans) are involved also in NK cell recognition and perhaps this is why they are expressed so early. NK cells are first responders to a viral infection. To know how NK cells in ducks work, we will identify NK cell receptors from our 50 ducks. Again we expect these to be different between individuals, and some may be better at controlling NK cell killing. Our research will contribute to understanding the ways in which influenza viruses exploit the duck as a host and reservoir. While we focus mainly on wild ducks, this work can inform breeding and selection of influenza-resistant ducks and conservation of natural populations in the wild.