Elucidation of mechanisms that contribute to antigenic drift of influenza viruses

阐明导致流感病毒抗原漂移的机制

• 批准号: 8099226
• 负责人: Scott Eric Hensley
• 金额: $ 16.2万
• 依托单位: WISTAR INSTITUTE
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-05-01 至 2013-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8099226
• 关键词: Antibodies; Antibody Binding Sites; Antibody Formation; Antibody Repertoire; Antigenic Diversity; Area; Avidity; Binding; Biological Assay; Cell Line; Cells; Cessation of life; Engineering; Escape Mutant; Evolution; Failure; Family suidae; Ferrets; Generations; Goals; Hemagglutinin; Human; Humoral Immunities; In Vitro; Individual; Infection; Influenza A Virus, H1N1 Subtype; Influenza A Virus, H3N2 Subtype; Influenza A virus; K22 Award; Laboratories; Link; Lung; Membrane Proteins; Modeling; Molecular Conformation; Monoclonal Antibodies; Mus; Mutate; Mutation; Neuraminidase; Point Mutation; Population; Process; Property; Public Health; Puerto Rico; Seasons; Sialic Acids; Site; Specificity; Testing; United States; Vaccination; Vaccine Design; Vaccines; Variant; Viral; Viral Proteins; Viral Vaccines; Virus; Virus Receptors; Work; anti-influenza; base; career; fitness; in vitro Assay; in vivo; in vivo Model; influenzavirus; mouse model; mutant; neutralizing antibody; pathogen; prevent; receptor; receptor binding; research study; response; seasonal influenza; sialic acid receptor; skills; transmission process

DESCRIPTION (provided by applicant): It is difficult to make vaccines against influenza A viruses (IAVs) due to the accumulation of mutations in antibody binding sites on the external proteins of these viruses. The mechanisms that promote this process, termed antigenic drift, are poorly understood. There are fairly effective vaccines for IAVs, but vaccine failure is common due to antigenic drift, and seasonal IAVs contribute to over 30,000 deaths in the US annually. The work outlined in this proposal will elucidate mechanisms involved during antigenic drift of IAVs. The current paradigm of how IAVs undergo antigenic drift is largely based on in vitro and in ovo studies showing that the virus can accumulate sequential mutations when grown in the presence of single monoclonal antibodies. Using a mouse model, we have found that antigenic drift of a classical H1N1 IAV occurs in vivo as the virus adjusts receptor binding avidity when confronted with different levels of sub-neutralizing antibodies. From these studies we propose that antigenic drift primarily occurs as a byproduct of receptor binding modulation rather than directly from mutations that abolish antibody binding per se. In this proposal we will first determine if additional subtypes of IAVs utilize this receptor-modulating mechanism during antigenic drift and we will examine if viral fitness is compromised during this process. To do this, we will use mice to model in vivo antigenic drift of 2 IAVs that circulate in humans (H3N2 and swine-origin H1N1 IAVs). Next, we will continue to use the mouse model to determine if the quality and specificity of anti-IAV antibody responses influence mutation selection in vivo. In these experiments, we will precisely define anti-IAV antibody repertoires that are induced in individual mice following different pre-exposure regiments and we will complete passive transfer studies to determine how quantitatively and qualitatively different antibody responses alter mutant selection. Finally, we will test the hypothesis that receptor diversity promotes antigenic diversity of IAVs. For these studies, we will select variants in vitro in cell lines that have different receptor compositions and we will complete in vivo studies in mice that lack specific IAV receptors. Collectively these studies will increase our understanding of antigenic drift of IAV viruses and will ultimately aid in the rational design of vaccines. The overall career goal of the candidate is to establish an independent academic laboratory that focuses on basic mechanisms of pathogen-host interactions. The K22 award will help the candidate achieve this goal and will further develop the candidate's scientific and professional skills. Project Narrative: Most viral vaccines work by inducing antibodies, which are molecules that prevent pathogens from entering and replicating in cells. Vaccines can be ineffective when viruses acquire mutations that prevent the binding of antibodies. The purpose of this work is to understand how influenza A viruses accumulate these types of mutations.

描述（由申请方提供）：由于甲型流感病毒（IAV）外部蛋白上抗体结合位点的突变累积，因此难以制备针对这些病毒的疫苗。促进这一过程的机制，称为抗原漂移，知之甚少。有相当有效的IAV疫苗，但由于抗原漂移，疫苗失败是常见的，季节性IAV每年在美国造成超过30，000人死亡。在这项建议中概述的工作将阐明IAV抗原漂移过程中涉及的机制。IAV如何经历抗原漂移的当前范例主要基于体外和卵内研究，这些研究表明，当在单克隆抗体存在下生长时，病毒可以积累连续突变。使用小鼠模型，我们已经发现经典H1N1 IAV的抗原漂移在体内发生，因为当面对不同水平的亚中和抗体时，病毒调节受体结合亲合力。从这些研究中，我们提出抗原漂移主要是作为受体结合调节的副产物而发生的，而不是直接来自消除抗体结合本身的突变。在这项提案中，我们将首先确定是否有其他亚型的IAV在抗原漂移过程中利用这种受体调节机制，我们将检查病毒适应性是否在这一过程中受到损害。为了做到这一点，我们将使用小鼠来模拟在人类中循环的2种IAV（H3 N2和猪源H1N1 IAV）的体内抗原漂移。接下来，我们将继续使用小鼠模型来确定抗IAV抗体应答的质量和特异性是否影响体内突变选择。在这些实验中，我们将精确定义不同预暴露方案后个体小鼠中诱导的抗IAV抗体库，我们将完成被动转移研究，以确定不同抗体反应如何定量和定性地改变突变体选择。最后，我们将测试的假设，受体多样性促进抗原多样性的IAV。对于这些研究，我们将在体外细胞系中选择具有不同受体组成的变体，并且我们将在缺乏特异性IAV受体的小鼠中完成体内研究。总的来说，这些研究将增加我们对IAV病毒抗原漂移的理解，并最终有助于疫苗的合理设计。候选人的总体职业目标是建立一个独立的学术实验室，专注于病原体-宿主相互作用的基本机制。K22奖将帮助候选人实现这一目标，并将进一步发展候选人的科学和专业技能。 大多数病毒疫苗通过诱导抗体起作用，抗体是防止病原体进入细胞并在细胞中复制的分子。当病毒获得阻止抗体结合的突变时，疫苗可能无效。这项工作的目的是了解甲型流感病毒如何积累这些类型的突变。