Structure-based expansion of neutralization ability of KD-247, an anti-V3 mAb

基于结构的抗 V3 单克隆抗体 KD-247 中和能力的扩展

• 批准号: 8137775
• 负责人: Stefan G Sarafianos
• 金额: $ 18.75万
• 依托单位: UNIVERSITY OF MISSOURI-COLUMBIA
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-10 至 2013-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8137775
• 关键词: Affinity; Amino Acids; Antibodies; Antigens; Binding; Biochemical; CCR5 gene; Clinical Treatment; Clinical Trials; Complex; Drug Delivery Systems; Drug resistance; Drug usage; Engineering; Epitopes; Evaluation; Fab Immunoglobulins; Generations; Goals; HIV; HIV Envelope Protein gp120; HIV Infections; HIV therapy; HIV-1; In Vitro; Infection; Integrase; Knowledge; Length; Membrane Glycoproteins; Molecular; Molecular Models; Monoclonal Antibodies; Mutate; Mutation; Patients; Peptide Hydrolases; Peptides; Pharmaceutical Preparations; Phase; Property; Proteins; RNA-Directed DNA Polymerase; Reporting; Resistance; Resolution; Site-Directed Mutagenesis; Specificity; Structure; Surface Plasmon Resonance; T-20; Testing; Therapeutic; V3 Loop; Vaccine Design; Variant; Viral; Viral Load result; Virus; Virus Replication; Work; antibody engineering; base; design; design and construction; engineering design; humanized antibody; humanized monoclonal antibodies; improved; in vivo; inhibitor/antagonist; innovation; instrument; molecular modeling; mutant; novel therapeutics; protocol development; public health relevance; resistant strain; tool

DESCRIPTION (provided by applicant): Anti-HIV treatments have been very successful in suppressing viral load in HIV-infected patients. However, new therapeutic strategies are needed to circumvent the inevitable selection of viruses that are resistant to all currently used drugs. Of the 32 drugs approved for the treatment of HIV infection, only two block viral entry, and there are no approved drugs that target the HIV surface glycoprotein gp120. KD-247 is a promising humanized monoclonal antibody (mAb) that has been developed by collaborator Dr. Shuzo Matsushita and colleagues. It binds the V3 loop of gp120 and neutralizes extremely potently a broad panel of diverse clade B HIV-1 isolates. Moreover, KD-247 suppresses replication of viral strains that are resistant to all currently approved drugs. Based on its promising properties, KD-247 has entered Phase Ib clinical trials for the treatment of HIV-1 infections. However, KD-247 like other anti-V3 antibodies lacks cross- clade neutralization ability. The structural basis for the clade specificity of KD-247 is unclear. This proposal will focus on the use of structure-based design to construct second generation single-chain variable fragments (scFvs) of KD-247 with broader clade specificity. In preliminary results, we have solved the crystal structure of the unliganded antigen-binding fragment (Fab) of KD-247 at the highest resolution (1.55 E) reported for any humanized antibody to date. We have also obtained a cloned scFv based on wild-type KD-247 to be used for the construction of mutants and performed molecular modeling studies that will initially guide the selection of scFv mutations. We propose to extend these studies to pursue the following specific aims: 1. To determine why KD-247 neutralizes efficiently a broad spectrum of clade B isolates 2. To design, construct, and evaluate scFv KD-247 that effectively bind clade B AND non-clade B isolates Achieving the aims of this proposal will provide structural, biochemical, and virological knowledge that will direct the design and engineering of second generation anti-V3 antibodies with improved potency and broader neutralization ability. In addition, our expected high-resolution structures will also provide essential information about molecular protein-protein contacts important for antibody recognition of specific antigens. Structure-based anti-HIV mAb engineering is an innovative approach that can serve as a paradigm for the design of additional therapeutics. PUBLIC HEALTH RELEVANCE: This project will determine crystal structures of KD-247, a monoclonal antibody currently in clinical trials, that will help us understand why it works well with many, but not all types of HIV. This knowledge will help us design second generation antibodies with broader neutralization ability.

描述(申请人提供)：抗艾滋病毒治疗在抑制艾滋病毒感染患者的病毒载量方面非常成功。然而，需要新的治疗策略来绕过对目前使用的所有药物都具有抗药性的不可避免的病毒选择。在批准用于治疗艾滋病毒感染的32种药物中，只有两种阻止病毒进入，而且没有针对艾滋病毒表面糖蛋白gp120的批准药物。KD-247是一种很有前途的人源化单抗(MAb)，它是由松下修三博士及其同事开发的。它结合了gp120的V3环，并非常有效地中和了一大批不同的B分支HIV-1分离株。此外，KD-247抑制了对目前批准的所有药物都有抗药性的病毒株的复制。基于其前景看好的特性，KD-247已进入治疗HIV-1感染的Ib期临床试验。然而，KD-247与其他抗V3抗体一样，缺乏跨分支中和能力。KD-247的支系特异性的结构基础尚不清楚。这项建议将集中于使用基于结构的设计来构建具有更广泛分支特异性的KD-247的第二代单链可变片段(ScFv)。在初步结果中，我们已经以迄今为止人源化抗体的最高分辨率(1.55E)解决了KD-247的未连接抗原结合片段(FAB)的晶体结构。我们还获得了基于野生型KD-247的克隆单链抗体，用于构建突变体，并进行了分子模拟研究，初步指导单链抗体突变的选择。我们建议将这些研究扩展到以下特定目标：1.确定KD-247为什么能有效中和广谱的B分支分离株2.设计、构建和评估能有效结合B分支和非B分支分离株的单链抗体KD-247，以实现这一建议的目标，将提供结构、生化和病毒学知识，指导第二代抗V3抗体的设计和工程，具有更高的效力和更广泛的中和能力。此外，我们预期的高分辨率结构还将提供有关分子蛋白质-蛋白质接触的基本信息，这些信息对于抗体识别特定抗原非常重要。基于结构的抗HIV单抗工程是一种创新的方法，可以作为设计额外疗法的范例。 公共卫生相关性：该项目将确定KD-247的晶体结构，这是一种目前处于临床试验中的单抗，这将帮助我们了解为什么它对许多类型的艾滋病毒，但不是所有类型的艾滋病毒都有效。这些知识将帮助我们设计具有更广泛中和能力的第二代抗体。