Shifting immunodominance of humoral immunity against influenza viruses

改变体液免疫对流感病毒的免疫优势

• 批准号: 10720359
• 负责人: Jenna Guthmiller
• 金额: $ 44.99万
• 依托单位: UNIVERSITY OF COLORADO DENVER
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-08-22 至 2028-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10720359
• 关键词: 2019-nCoV; Adult; Affinity; Antibodies; Antibody Binding Sites; Antibody Response; Antigen Presentation; Antigenic Variation; Antigens; Avidity; B-Cell Antigen Receptor; B-Lymphocytes; Binding; Binding Sites; CD4 Positive T Lymphocytes; Coronavirus; Ebola virus; Epitopes; Exposure to; Flavivirus; Frequencies; Generations; HIV; Hantavirus; Head; Health; Helper-Inducer T-Lymphocyte; Hemagglutinin; Human; Humoral Immunities; Immune; Immune system; Immunity; Immunize; Immunologics; Individual; Infant; Influenza A Virus, H1N1 Subtype; Knowledge; Laboratories; Libraries; Memory B-Lymphocyte; Modeling; Monoclonal Antibodies; Mus; Mutagenesis; Mutate; Mutation; Organoids; Parasites; Plasmodium; Play; Population; Postdoctoral Fellow; Pre-Clinical Model; Recording of previous events; Research; Role; Seasons; Serum; Shapes; Site; Specificity; T cell response; Testing; Titrations; Vaccination; Vaccine Antigen; Vaccine Design; Vaccines; Variant; Virus; Work; Yeasts; anti-influenza; combinatorial; crosslink; design; emerging pathogen; experimental study; improved; influenza virus vaccine; influenzavirus; lymph nodes; memory recall; monoclonal antibody production; neoantigens; novel; pandemic disease; pathogen; prevent; rational design; recruit; response; seasonal influenza; translational immunology; vaccine candidate; vaccine efficacy; vaccine evaluation

PROJECT SUMMARY Influenza viruses remain a major global threat to human health, which is exacerbated by the lack of an effective vaccine. Humoral immunity does not target all parts of the virus evenly, a phenomenon known as immunodominance. Following seasonal vaccination, humans preferentially generate antibody responses against evolving epitopes of the hemagglutinin (HA) head domain rather than against broadly protective epitopes of the conserved stalk domain. In the absence of preexisting immunity against the HA head, as occurred with the 2009 pandemic H1N1 virus, humans can preferentially recall memory B cells against the stalk domain. However, naïve B cells against novel epitopes of the HA head are induced, populate the memory B cell pool, and are preferentially recalled following exposure to an antigenically similar virus. Therefore, immunodominance of the head domain and the preferential recruitment of naïve B cells against new epitopes remains a major obstacle for the generation of a broadly protective influenza vaccine. In order to generate broadly protective humoral immunity, a vaccine needs to be designed that induces robust and durable antibody responses against the stalk domain but prevents the recruitment of naïve B cells against neoepitopes. Immunodominance is in part dictated by which B cells can acquire antigen and efficiently present antigen to CD4 T cells. B cell avidity, the simultaneous binding of both binding-sites of an antibody with its epitope and the cross- linking of multiple B cell receptors on a B cells, plays a critical role in which B cell specificities are selected. B cells against the head domain have an avidity advantage, as these epitopes are more accessible than those of the stalk domain. We hypothesize that reducing B cell avidity for head epitopes will reduce competition for antigen, limit the induction of anti-head B cells, and preferentially select for B cells against the stalk domain. Using combinatorial mutagenesis and yeast-display, we will generate and select for a library of stable HAs with diverse head epitopes but an identical stalk domain, which we refer to as scrambled HA (Aim 1). By titrating the diversity of scrambled HAs, we will determine the effect of increasing head epitope diversity on which B and T follicular helper cell specificities are induced. We will perform these experiments in naïve and H1N1 immune mice to mimic immune histories in infants and adults, respectively (Aim 2). Moreover, we will immunize human ex vivo lymph node organoids generated from individuals of diverse immune histories to determine if our approach recalls memory B cells against the stalk domain (Aim 3). Together, this study will generate a vaccine that shifts immunodominance towards the stalk domain, which will be proven using multiple models of preexisting immunity. Although this proposal focuses on shifting immunodominance of anti-influenza humoral immunity, the approach taken provides a proof-of-concept that can be applied to other rapidly evolving pathogens for which immunodominance is a key barrier for successful vaccine generation, including HIV and coronaviruses.

项目摘要 流感病毒仍然是对人类健康的主要全球威胁，由于缺乏有效的预防措施， 疫苗体液免疫并不是均匀地针对病毒的所有部分，这种现象被称为 免疫优势在季节性疫苗接种后，人类优先产生针对 血凝素（HA）头部结构域的进化表位，而不是针对血凝素（HA）头部结构域的广泛保护性表位。 保守茎域。由于医管局首长没有先前存在的豁免权，如2009年 大流行性H1N1病毒，人类可以优先回忆记忆B细胞对茎域。然而，天真 诱导针对HA头部的新表位的B细胞，使其填充记忆B细胞库，并 在暴露于抗原性相似的病毒后优先回忆。因此， 头部结构域和针对新表位的幼稚B细胞的优先募集仍然是 一种具有广泛保护性的流感疫苗的产生。为了产生广泛的保护性体液， 为了提高免疫力，需要设计一种疫苗， 结构域，但阻止针对新表位的幼稚B细胞的募集。 免疫优势部分取决于B细胞能够获得抗原并有效地将抗原呈递给CD4 T细胞。B细胞亲合力，抗体的两个结合位点与其表位的同时结合，以及抗体的交叉结合。 B细胞上多个B细胞受体的连接在选择B细胞特异性中起关键作用。B 针对头部结构域的细胞具有亲合力优势，因为这些表位比针对头部结构域的细胞更容易接近。 茎域我们假设，降低B细胞对头部表位的亲合力将减少对头部表位的竞争。 抗原，限制抗头部B细胞的诱导，并优先选择针对茎结构域的B细胞。 使用组合诱变和酵母展示，我们将产生并选择具有以下功能的稳定HA文库： 不同的头部表位，但相同的茎域，我们称之为乱序HA（Aim 1）。通过滴定 我们将确定增加头部表位多样性对B和T 诱导滤泡辅助细胞特异性。我们将在幼稚和H1N1免疫中进行这些实验 小鼠分别模拟婴儿和成人的免疫史（目的2）。此外，我们将免疫人类 从不同免疫史的个体产生的离体淋巴结类器官，以确定我们的 方法针对茎域召回记忆B细胞（Aim 3）。总之，这项研究将产生一种疫苗， 将免疫优势转移到茎域，这将使用多种先前存在的 免疫力尽管该建议的重点是改变抗流感体液免疫的免疫优势， 所采取的方法提供了一种概念验证，可应用于其他快速进化的病原体， 免疫优势是成功生产疫苗的关键障碍，包括艾滋病毒和冠状病毒。