Role of immunoglobulin CDR-H3 in heterosubtypic immunity to influenza virus

免疫球蛋白CDR-H3在流感病毒异亚型免疫中的作用

• 批准号: 8103875
• 负责人: Harry William Schroeder
• 金额: $ 21.76万
• 依托单位: UNIVERSITY OF ALABAMA AT BIRMINGHAM
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-07-05 至 2013-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8103875
• 关键词: Affect; Age; Alleles; Americas; Antibodies; Antibody Repertoire; Antigen Presentation; B-Lymphocytes; Binding Sites; Bone Marrow; Bone Marrow Cells; Categories; Cells; Charge; Competence; Coupled; Development; Disease; Dominant-Negative Mutation; Gene Targeting; Human; Immune; Immune response; Immunity; Immunoglobulins; Immunologist; Inbred BALB C Mice; Individual; Infection; Influenza A Virus, H1N1 Subtype; Laboratories; Lead; Life; Methodology; Mononuclear; Morbidity - disease rate; Mouse Strains; Mus; Mutation; Predisposition; Prevalence; Preventive; Production; Receptors, Antigen, B-Cell; Research Personnel; Resistance; Risk; Role; Serum; Staging; T-Lymphocyte; Testing; Transgenic Mice; Transplantation; Tyrosine; Vaccines; Virus; Virus Diseases; Wild Type Mouse; Work; aged; anti-influenza; antigen binding; chemical property; experience; influenzavirus; interest; mortality; mutant; novel; pandemic disease; pressure; prevent; public health relevance; response; treatment strategy; vaccination strategy; young adult

DESCRIPTION (provided by applicant): We seek to gain a better understanding of the role of the antibody repertoire as a whole in providing heterosubtypic immunity to influenza virus. We have found that we can group of antigen binding sites into categories defined by specific physical-chemical properties. We have shown that some categories are preferred at key stages of life, whereas others appear to be actively selected against, especially in young adults who typically are more resistant to heterosubtypic infection than aged individuals. Preliminary studies indicate that immunoglobulins using 'disfavored' categories of antigen binding sites can be found in aged individuals. Because the general principles of antibody repertoire control appear common to human and mouse, in order to study the role of repertoire control in heterosubtypic immunity we created mice whose repertoire is limited to one of these highly disfavored categories. We previously used these mice to show that when antibodies bearing antigen binding sites belonging to normally preferred categories were completely replaced by antibodies using a disfavored category, protection against heterosubtypic challenge with an H1N1 strain was severely compromised. However, these studies did not answer the question of whether it was the absence of the normally preferred repertoire or the presence of sequences belonging to a disfavored category that had impaired heterosubtypic immunity. In the present proposal, we test the hypothesis that the presence of disfavored immunoglobulin can have a dominant negative effect on protection against heterosubtypic infection. This is a key issue because, as noted above, the composition of the repertoire can change with age or disease. Mice heterozygous for altered IgH alleles containing mutations in the DH locus produce a normal repertoire from the normal allele, and disfavored antibodies from the gene targeted allele. These mice will be used to test whether the presence of these disfavored antibodies is sufficient to increase morbidity and mortality after mice are immunized with either an H3N2 or an H1N1 strain, and then challenged with homologous or heterologous viruses. The increase in morbidity and mortality will confirm that control of the global composition of the antibody repertoire is essential for properly protective immune responses to influenza virus. Two potential mechanisms that could underlie this increases susceptibility to infection will then be tested. Mice will be injected with sera or infused with bone marrow mononuclear cells from naove or immunized mice, and then challenged with homologous or heterologous viruses. An increase in morbidity after administration with the sera will point to a direct effect of soluble disfavored antibody. An increase in morbidity only after transfer of cells will suggest a direct role of immunoglobulin as a B cell receptor, perhaps by altering antigen presentation to T cells. We will then titer the effect to determine the threshold beyond which heterosubtypic immunity is impaired. Coupled with new means to evaluate repertoire diversity, this information will then be used to inform susceptibility to influenza virus infections and to guide vaccination and treatment strategies. PUBLIC HEALTH RELEVANCE: We seek to understand how the composition of the totality of antibodies produced by the body may affect protection against influenza virus. We plan to use this information both to identify individuals at risk for greater morbidity and mortality, and to guide vaccination and treatment strategies.

描述（由申请人提供）：我们寻求更好地了解抗体库作为一个整体在提供针对流感病毒的异亚型免疫方面的作用。我们发现我们可以将抗原结合位点分为由特定物理化学性质定义的类别。我们已经证明，某些类别在生命的关键阶段是首选的，而其他类别似乎是被积极选择的，特别是在年轻人中，他们通常比老年人对异亚型感染具有更强的抵抗力。初步研究表明，在老年人中可以发现使用“不受欢迎”类别的抗原结合位点的免疫球蛋白。由于抗体库控制的一般原理对于人类和小鼠来说似乎是共同的，为了研究库控制在异亚型免疫中的作用，我们创建了小鼠，其库仅限于这些高度不受欢迎的类别之一。我们之前使用这些小鼠来证明，当带有属于通常优选类别的抗原结合位点的抗体被使用不受欢迎类别的抗体完全取代时，针对 H1N1 毒株的异亚型攻击的保护作用受到严重损害。然而，这些研究并没有回答这样的问题：是否存在通常优选的序列，或者是否存在属于不受欢迎类别的序列，从而损害了异亚型免疫。在本提案中，我们测试了以下假设：不利的免疫球蛋白的存在可能对异亚型感染的保护产生显着的负面影响。这是一个关键问题，因为如上所述，曲目的组成会随着年龄或疾病而变化。含有 DH 基因座突变的 IgH 等位基因杂合的小鼠会产生来自正常等位基因的正常抗体库，以及来自基因靶向等位基因的不利抗体。这些小鼠将用于测试在用 H3N2 或 H1N1 毒株免疫小鼠，然后用同源或异源病毒攻击后，这些不利抗体的存在是否足以增加发病率和死亡率。发病率和死亡率的增加将证实，控制抗体库的整体组成对于针对流感病毒的适当保护性免疫反应至关重要。然后将测试可能导致感染易感性增加的两种潜在机制。小鼠将被注射血清或输注来自幼稚或免疫小鼠的骨髓单核细胞，然后用同源或异源病毒攻击。施用血清后发病率的增加表明可溶性不利抗体的直接影响。仅在细胞转移后发病率的增加表明免疫球蛋白作为 B 细胞受体的直接作用，可能是通过改变 T 细胞的抗原呈递来实现的。然后我们将滴度效应以确定异亚型免疫受损的阈值。结合评估病毒库多样性的新方法，这些信息将用于了解流感病毒感染的易感性并指导疫苗接种和治疗策略。 公共卫生相关性：我们试图了解人体产生的抗体总量的组成如何影响对流感病毒的保护。我们计划利用这些信息来识别有更高发病率和死亡率风险的个体，并指导疫苗接种和治疗策略。