Role of IG CDR-H3 in Responses to HIV Vaccines

IG CDR-H3 在 HIV 疫苗反应中的作用

• 批准号: 8294974
• 负责人: Harry William Schroeder
• 金额: $ 36.52万
• 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 2014-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8294974
• 关键词: Acquired Immunodeficiency Syndrome; Address; Amino Acids; Animal Model; Animals; Antibodies; Antibody Formation; Antibody Repertoire; Antigens; Autoimmunity; B-Cell Development; B-Lymphocyte Subsets; B-Lymphocytes; Binding; Binding Sites; Biological Assay; Breeding; C57BL/6 Mouse; CCR5 gene; CD19 gene; CXCR4 gene; Cell Survival; Cells; Charge; Collaborations; Complementarity Determining Region III; Complex; Development; Disease Progression; Epitopes; Fostering; Frequencies; Gene Targeting; Generations; Genetic; Genetic Predisposition to Disease; Glycoproteins; Goals; Graafian Follicles; HIV; HIV Envelope Protein gp120; HIV vaccine; HIV-1; Human; Hybridomas; Hydrophobicity; Immune; Immune response; Immune system; Immunization; Immunoglobulin Somatic Hypermutation; Immunoglobulins; Immunologist; Inbred BALB C Mice; Individual; Infection; Jaw; Laboratories; Liposomes; Medical; Membrane; Membrane Lipids; Memory; Mus; Mutation; Outcome; Patients; Pattern; Peptides; Population; Process; Production; Proteins; Reporting; Role; SLEB1 gene; SLEB2 gene; SLEB3 gene; Signal Transduction; Source; Specificity; Structure; Surface; Testing; Touch sensation; Treatment Cost; Tyrosine; Vaccines; Vertebrates; Virion; Work; antigen binding; antiretroviral therapy; base; cell type; complementarity-determining region 3; congenic; cross reactivity; design; env Gene Products; experience; large scale production; neutralizing antibody; novel vaccines; pandemic disease; polyclonal antibody; prevent; programs; receptor; receptor binding; response; sugar; vaccination strategy; virus envelope

DESCRIPTION (provided by applicant): Among neutralizing antibodies (Nabs) directed against the HIV-1 envelope gp120/gp41 glycoprotein, 2F5 and 4E10 stand out for their potency and broadly neutralizing activity. Both antibodies are directed against the membrane proximal external region (MPER) of the gp41 stalk. Unfortunately, 2F5 and 4E10-like anti-MPER Nabs are rarely major components of the anti-HIV response. 2F5 and 4E10 differ from the norm in that each of their antigen binding sites contain a long, H chain complementarity determining region 3 (CDR-H3) that lacks tyrosine and includes patches of hydrophobic and charged amino acids. In previous studies we have shown that B cells bearing immunoglobulins with charged or hydrophobic CDR-H3s are normally culled from the follicular and mature, recirculating B cell subsets, i.e. the subsets from which T-dependent antibody responses are most likely to be drawn. We propose to test whether 2F5- and 4E10-like Nabs are difficult to elicit in healthy individuals because the frequency of B cells expressing Igs with this type of antigen binding site is deliberately kept low by both genetic and somatic mechanisms. We will do this by using gene targeting to replace the DH locus with a DH encoding the CDR-H3 sequence of either 2F5 or 4E10. This will force expression of a spectrum of antibodies expressing 2F5 and 4E10-like CDR-H3s. We will then test whether forced enrichment for the use of 2F5- and 4E10-derived CDR-H3 intervals will promote the production of Nabs directed against the HIV-1 MPER. To test the complementary hypothesis that the use of 2F5- and 4E10-derived CDR-H3 intervals in anti-MPER Nabs may require release from normal mechanisms of repertoire control, we will breed into these mice mutations that alter patterns of B cell signaling, repertoire selection, or cell fate outcomes. The application is responsive to the RFA in that it is specifically designed to determine "why broadly neutralizing antibodies that arise from infection are rare and how immunogens can elicit them" and to develop "more relevant animal models in which protection or enhancement of infection can be explored." Our studies also touch on "Modulating and/or specifically suppressing component aspects of the immune response to alter disease progression" in the context of determining how to manipulate the immune response in order to optimally generate protective antibodies against HIV. These studies will also serve to foster collaboration between three established basic B cell immunologists at UAB, Drs. Schroeder, Justement and Kearney; and three experts in HIV, Drs. Haynes at Duke, Grovit-Ferbas at UCLA, and Shaw at UAB. The creation of vaccines capable of eliciting neutralizing antibodies to HIV has proven more difficult than first expected because many of the antibodies that are broadly neutralizing are not only extremely uncommon; they also tend to be self-reactive. We propose to use gene targeting in mice to force B cells, including the follicular subset, to preferentially express antibody repertoires enriched for antibodies of this type, and then test whether altering BCR signaling, repertoire selection or the type of immunogen (e.g. antigen encased in liposomes or antigen displayed by pseudovirions) will facilitate the generation of antibodies that can bind the key MPER region of the HIV envelope protein in a way that will enable them to broadly neutralize HIV.

描述（由申请人提供）： 在针对 HIV-1 包膜 gp120/gp41 糖蛋白的中和抗体 (Nab) 中，2F5 和 4E10 因其效力和广泛的中和活性而脱颖而出。两种抗体均针对 gp41 茎的近膜外部区域 (MPER)。不幸的是，2F5 和 4E10 样抗 MPER Nab 很少是抗 HIV 反应的主要组成部分。 2F5 和 4E10 与标准的不同之处在于，它们的每个抗原结合位点都包含一个长的 H 链互补决定区 3 (CDR-H3)，该区缺乏酪氨酸并包含疏水性和带电氨基酸的片段。在之前的研究中，我们已经表明，携带带有带电或疏水性 CDR-H3 的免疫球蛋白的 B 细胞通常是从滤泡和成熟的再循环 B 细胞亚群中挑选出来的，即最有可能从中产生 T 依赖性抗体反应的亚群。我们建议测试 2F5 和 4E10 样 Nab 是否难以在健康个体中引发，因为通过遗传和体细胞机制故意将表达具有此类抗原结合位点的 Igs 的 B 细胞保持在较低频率。我们将通过使用基因打靶将 DH 基因座替换为编码 2F5 或 4E10 的 CDR-H3 序列的 DH 来实现此目的。这将强制表达一系列表达 2F5 和 4E10 样 CDR-H3 的抗体。然后，我们将测试使用 2F5 和 4E10 衍生的 CDR-H3 间隔进行强制富集是否会促进针对 HIV-1 MPER 的 Nab 的产生。为了测试补充假设，即在抗 MPER Nab 中使用 2F5 和 4E10 衍生的 CDR-H3 间隔可能需要从正常的库控制机制中释放，我们将在这些小鼠中培育突变，从而改变 B 细胞信号传导模式、库选择或细胞命运结果。该应用程序是对 RFA 的响应，因为它专门设计用于确定“为什么感染产生的广泛中和抗体很少见以及免疫原如何引发它们”，并开发“可以探索保护或增强感染的更相关的动物模型”。我们的研究还涉及“调节和/或特异性抑制免疫反应的组成部分以改变疾病进展”，以确定如何操纵免疫反应，以最佳地产生针对 HIV 的保护性抗体。这些研究还将有助于促进 UAB 三位基础 B 细胞免疫学家、Drs. 之间的合作。施罗德、Justement 和科尔尼；和三位艾滋病毒专家，博士。海恩斯在杜克大学，格罗维特-费巴斯在加州大学洛杉矶分校，肖在阿拉巴马大学伯明翰分校。事实证明，研制能够引发艾滋病毒中和抗体的疫苗比最初预期的更加困难，因为许多广泛中和的抗体不仅极其罕见，而且还非常罕见。他们也往往会做出自我反应。我们建议在小鼠中使用基因靶向，迫使 B 细胞（包括滤泡亚群）优先表达富含此类抗体的抗体库，然后测试改变 BCR 信号传导、库选择或免疫原类型（例如脂质体中包裹的抗原或假病毒粒子展示的抗原）是否会促进产生能够结合该类型抗体的抗体。 HIV 包膜蛋白的关键 MPER 区域使它们能够广泛中和 HIV。