Optimizing HIV Env immuogens for T and B cell vaccine responses

优化 HIV 包膜免疫原以实现 T 和 B 细胞疫苗反应

• 批准号: 8505364
• 负责人: James A Hoxie
• 金额: $ 51.77万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-07-01 至 2015-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8505364
• 关键词: Address; Affinity; Animal Model; Antibodies; Antibody Binding Sites; Antibody Formation; Antigens; B-Lymphocytes; Binding; Binding Sites; Biological Models; Biology; CCR5 gene; CD4 Positive T Lymphocytes; CD8B1 gene; Carbohydrates; Cell fusion; Cell physiology; Cell surface; Cells; Clinical Trials; Cytoplasmic Tail; Data; Data Analyses; Development; Epitopes; Excision; Exhibits; Failure; Frequencies; Goals; Grant; HIV; HIV Envelope Protein gp120; HIV vaccine; HIV-1; Human; Immune; Immune response; Immunization; Immunosuppression; Immunosuppressive Agents; In Vitro; Infection; Lead; Mediating; Membrane; Mus; Mutagenesis; Mutate; Nucleic Acids; Plasmids; Play; Property; Protein Subunits; Proteins; Role; SIV; Signal Transduction; Site; Structure; Surface; System; T cell response; T-Cell Proliferation; T-Lymphocyte; Testing; Transgenic Mice; Vaccines; Viral; Viral Vector; Virus; base; design; env Glycoproteins; immunogenicity; improved; in vitro Model; in vivo; innovation; insight; neutralizing antibody; neutralizing monoclonal antibodies; novel; prevent; response; screening; vaccine development; vector

DESCRIPTION (provided by applicant): A push to perform more basic studies has emerged in the HIV vaccine field given the often poor results in vaccine trails. As HIV is an immunosuppressive virus and many of its proteins alter cellular function, an important basic question that needs to be answered is what effect does using HIV proteins in a vaccine have on induced immune responses. We demonstrated that HIV Env, when delivered as a vaccine that presents cell-associated trimers, suppresses antigen-specific CD4+ T cell responses. We demonstrated that functional trimeric Env aberrantly signaled CD4+ T cells and blocked their expansion, which could lead to a deficiency in help for neutralizing antibody and CD8+ T cell responses. We propose to develop an Env immunogen that when presented as a functional cell surface trimer does not signal through CD4 thereby preserving CD4 help and retains epitopes capable of inducing broadly cross-reactive neutralizing antibodies. This Env should induce stronger CD8+ T cell responses and neutralizing antibodies because of better or altered exposure of neutralizing epitopes, which will be selected for, and increased CD4 help. We will also study whether Env immunogens that retain the ability to mediate entry and cell-cell fusion will present functional domains that are most relevant to neutralization and will provide additional advantages as immunogens. We will use a novel small animal model that will allow us to screen immunogens for both Env mediated immunosuppressive activities and T and B cell immune responses. In three specific aims, we will develop and test Env immunogens. Specific Aim 1: immunogen development. An Env that does not bind or signal CD4 and retains broad neutralization epitopes (CD4bs, CD4i, MPER, carbohydrate (2G12), V2-V3) will be developed. Specific Aim 2: analysis of immunogens for CD4+ T cell suppression and cross-reactive neutralizing antibody epitope expression. Immunogens will be sequentially screened for CD4 binding, CD4 signaling, and ability to suppress CD4+ T cell proliferation. They will then be analyzed for binding by, and, if possible, inhibition by broadly cross- reactive neutralizing monoclonal antibodies. Data from these analyses will be used in the further development of immunogens in Aim 1. The 20 best immunogens from Aim 2 will be studied in Aim 3. Specific Aim 3: immunization of human CD4 and CD4/CCR5 transgenic mice for analysis of effective CD4+ T cell help, development of cross-reactive neutralizing antibody, and CD8+ T cell responses. We will test the hypothesis that Env immunogens that do not suppress CD4 help will have broader neutralizing antibody responses and better CD8 responses with regard to both frequency of antigen-specific cells and multifunctionality of cells. This study will analyze the effect of removal of the immunosuppressive activity of HIV Env on vaccine responses with the goal of developing a better immunogen. The need for an HIV vaccine to control spread is recognized as extremely important. Given the failure of recent clinical trials, studies that focus on the basic biology of vaccine development are warranted. This grant will study and develop new HIV envelope immunogens for vaccine development.

描述（由申请人提供）： 鉴于疫苗试验的结果往往不佳，艾滋病毒疫苗领域出现了开展更多基础研究的推动力。由于 HIV 是一种免疫抑制病毒，其许多蛋白质会改变细胞功能，因此需要回答的一个重要的基本问题是在疫苗中使用 HIV 蛋白质对诱导的免疫反应有何影响。我们证明，当 HIV Env 作为呈现细胞相关三聚体的疫苗提供时，可以抑制抗原特异性 CD4+ T 细胞反应。我们证明，功能性三聚体 Env 异常地向 CD4+ T 细胞发出信号并阻止其扩增，这可能导致中和抗体和 CD8+ T 细胞反应的帮助不足。我们建议开发一种 Env 免疫原，当其作为功能性细胞表面三聚体呈现时，不会通过 CD4 发出信号，从而保留 CD4 帮助并保留能够诱导广泛交叉反应中和抗体的表位。由于中和表位的更好或改变的暴露（将被选择）以及增加的CD4帮助，该Env应该诱导更强的CD8+T细胞反应和中和抗体。我们还将研究保留介导进入和细胞-细胞融合能力的Env免疫原是否会呈现与中和最相关的功能域，并提供作为免疫原的额外优势。我们将使用一种新型小动物模型，该模型使我们能够筛选 Env 介导的免疫抑制活性以及 T 和 B 细胞免疫反应的免疫原。为了三个具体目标，我们将开发和测试 Env 免疫原。具体目标 1：免疫原开发。 将开发一种不结合 CD4 或向 CD4 发出信号并保留广泛中和表位（CD4bs、CD4i、MPER、碳水化合物 (2G12)、V2-V3）的 Env。具体目标 2：分析 CD4+ T 细胞抑制和交叉反应中和抗体表位表达的免疫原。将依次筛选免疫原的 CD4 结合、CD4 信号传导以及抑制 CD4+ T 细胞增殖的能力。然后将分析它们的结合情况，如果可能的话，分析广泛交叉反应性中和单克隆抗体的抑制情况。这些分析的数据将用于目标 1 中免疫原的进一步开发。目标 2 中的 20 种最佳免疫原将在目标 3 中进行研究。具体目标 3：对人类 CD4 和 CD4/CCR5 转基因小鼠进行免疫，以分析有效的 CD4+ T 细胞帮助、开发交叉反应性中和抗体和 CD8+ T 细胞反应。我们将测试以下假设：不抑制 CD4 帮助的 Env 免疫原将在抗原特异性细胞的频率和细胞的多功能性方面具有更广泛的中和抗体反应和更好的 CD8 反应。本研究将分析消除 HIV Env 的免疫抑制活性对疫苗反应的影响，目的是开发更好的免疫原。人们认为需要一种艾滋病毒疫苗来控制传播极其重要。鉴于最近临床试验的失败，有必要对疫苗开发的基础生物学进行研究。这笔赠款将研究和开发用于疫苗开发的新的艾滋病毒包膜免疫原。