Potent Phage T4 Derived V2 Immunogens as HIV Vaccines

有效的噬菌体 T4 衍生 V2 免疫原作为 HIV 疫苗

• 批准号: 8410257
• 负责人: Venigalla B. Rao
• 金额: $ 41.38万
• 依托单位: CATHOLIC UNIVERSITY OF AMERICA
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-07-01 至 2016-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8410257
• 关键词: Acute; Adjuvant; Affinity; Antibodies; Antigens; Bacteriophage T4; Bacteriophages; Binding; Biological Assay; Biological Process; Blocking Antibodies; CCR5 gene; Capsid; Capsid Proteins; Cells; Chinese Hamster Ovary Cell; Clinical Trials; Dendritic Cells; Development; Engineering; Enterotoxins; Epitopes; Exposure to; Genome; Goals; HIV; HIV vaccine; HIV-1; Heating; Immune response; In Vitro; Incubated; Integrins; Intramuscular; Length; Libraries; Ligands; Membrane; Modeling; Molecular Conformation; Molecular Genetics; Monoclonal Antibodies; Mus; Mutation; Oryctolagus cuniculus; Pattern; Phase; Play; Protein Binding; Proteins; Reporting; Route; Sexual Transmission; Site; Skin; Specificity; Surface; System; T-Lymphocyte; Testing; Time; Transplantation; Vaccination; Vaccines; Variant; Virus; base; fitness; glycosylation; high throughput screening; immunogenicity; nanoparticle; neutralizing antibody; nonhuman primate; novel; particle; prevent; prophylactic; scaffold; secretory protein; transmission process; vaccine candidate; vaccine delivery; vaccine development; virus host interaction

DESCRIPTION (provided by applicant): A major goal of this proposal is to develop a novel experimental paradigm to engineer preventative HIV-1 vaccines. The V1/V2 domain of HIV-1 envelope is an important target for vaccine development for several reasons. V2 interaction with the ¿4¿7 integrin of mucosal T cells may play a key role in the efficient capture of HIV-1 virus at the site of initial exposure during sexual transmission. The V1/V2 domain is also a key player in regulating neutralization sensitivity of HIV-1, and consists of epitopes recognized by some of the most potent broadly neutralizing antibodies reported to date. Here, we hypothesize that induction of antibodies by vaccination with V1/V2 immunogens that interferes, specifically with the V2 ¿4¿7 interactions, confers protection against HIV-1 acquisition. Since the conformation of V2 is highly variable, the V2 domain will be constrained by transplanting it into the compactly folded 9 kDa small outer capsid protein (Soc) from bacteriophage T4. To select for the functionally important V2 conformations, libraries of V2 domain variants consisting of founder/acute virus sequences, different glycosylation patterns, and random mutations will be constructed and expressed in CHO cells as secretory proteins. High throughput assays will be developed, one to select ¿4¿7 binding conformations and another to select V2 conformational antibody binding variants. The biologically active Soc-V2 conformational variants will be arrayed on phage T4 nanoparticles by incubating the purified Soc-V2 proteins with Soc-minus Hoc-minus phage, up to 870 copies per particle. A Hoc- fused targeting ligand such as Dec205 mAb will also be assembled on the same capsid, up to 155 copies per capsid, to target the T4-V2 nanoparticles to the antigen-presenting dendritic cells. The immunogenicity of T4-V2 nanoparticles will be evaluated in mice by intramuscular route as well as transcutaneous (skin) route using heat labile enterotoxin as an adjuvant. The immune responses will be quantified for V2- ¿4¿7 interfering antibodies, virus neutralizing antibodies and transmission-blocking antibodies. The best V2 variants down-selected from these assays will then be tested in the rabbit model. A novel HIV-1 transmission assay will be developed, which will precisely quantify the number of virus genomes that cross the host membrane after a few minutes of exposure to CD4+, ¿4¿7+ and CCR5+ T cells. Based on real-time PCR, this assay would be extremely sensitive, rapid, and high throughput. Using this assay, V2 variants that can induce antibodies which block virus entry by interfering with the initial virus-host interactions will be selected. These might potentially serve as preventative HIV-1 vaccine candidates for further studies in nonhuman primates and clinical trials. PUBLIC HEALTH RELEVANCE: The mechanism of HIV transmission at the site of exposure and how to develop vaccines that can prevent it remained as key goals in the development of preventative HIV vaccines. This proposal aims to analyze one of the HIV envelope components, the V1/V2 domain, which is involved in the initial interactions between the virus and the host. Using a combination of bacteriophage T4 display, molecular genetics, high throughput screening, and a new HIV transmission assay, V1/V2 nanoparticle immunogens that can induce transmission blocking antibodies will be selected as potential HIV preventative vaccines.

描述（由申请人提供）：本提案的一个主要目标是开发一种新的实验范式来设计预防性HIV-1疫苗。由于几个原因，HIV-1包膜的V1/V2结构域是疫苗开发的重要目标。V2与粘膜T细胞的¿4¿7整合素的相互作用可能在有效捕获HIV-1病毒中起关键作用