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.

项目概要 流感病毒仍然是全球对人类健康的主要威胁，由于缺乏有效的治疗方法，这一威胁更加严重。 体液免疫并不均匀地针对病毒的所有部分，这种现象称为 季节性疫苗接种后，人类优先产生针对其的抗体反应。 血凝素 (HA) 头域的进化表位，而不是针对广泛的保护性表位 保守的茎结构域缺乏预先存在的针对 HA 头的免疫力，如 2009 年所发生的那样。 在流行性 H1N1 病毒中，人类可以优先回忆针对茎结构域的记忆 B 细胞。 针对 HA 头新表位的 B 细胞被诱导，填充记忆 B 细胞库，并被 因此，在接触抗原相似的病毒后优先回忆。 头域和针对新表位优先招募初始 B 细胞仍然是 产生具有广泛保护性的流感疫苗。 为了获得免疫力，需要设计一种疫苗来诱导针对茎的强大而持久的抗体反应 域，但会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哪些 B 细胞可以获得抗原并有效地将抗原呈递给 CD4 T 细胞亲和力，抗体的两个结合位点与其表位和交叉结合的同时结合。 B 细胞上多个 B 细胞受体的连接在选择 B 细胞特异性方面发挥着关键作用。 针对头部结构域的细胞具有亲和力优势，因为这些表位比那些更容易接近 我们追求减少 B 细胞对头部表位的亲和力将减少对茎结构域的竞争。 抗原，限制抗头 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，我们将生成并选择稳定的 HA 文库 不同的头部表位但具有相同的茎结构域，我们将其称为乱序 HA（目标 1）。 扰乱 HA 的多样性，我们将确定增加头表位多样性对 B 和 T 的影响 我们将在首次免疫和 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（目标 2）。此外，我们还将对人类进行免疫。 从不同免疫系统的个体中产生的离体淋巴结类器官，以确定我们是否 方法召回针对茎结构域的记忆 B 细胞（目标 3），这项研究将共同​​产生一种疫苗。 将免疫优势转向茎域，这将使用预先存在的多种模型进行证明 尽管该提案的重点是改变抗流感体液免疫的免疫优势，但 所采取的方法提供了一个概念验证，可以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。