Antibody-based therapeutics and vaccines against AIDS

基于抗体的艾滋病疗法和疫苗

• 批准号: 8937983
• 负责人: Dimiter S Dimitrov
• 金额: $ 25.72万
• 依托单位: DIVISION OF BASIC SCIENCES - NCI
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/8937983
• 关键词: Acquired Immunodeficiency Syndrome; Adopted; Affinity; Animals; Anti-Retroviral Agents; Antibodies; Binding; Binding Sites; CD4 Positive T Lymphocytes; Chimeric Proteins; Complex; Computer Analysis; Data; Development; Disease; Drug resistance; Engineering; Epitopes; Exhibits; FDA approved; Generations; Glycoproteins; Goals; HIV; HIV Envelope Protein gp120; HIV Infections; HIV-1; Highly Active Antiretroviral Therapy; Human; Hydrophobicity; Immune System Diseases; Immune system; Immunity; Immunotherapy; Indium; Individual; Infection; Knowledge; Libraries; Lipids; Macaca; Macaca mulatta; Membrane; Modeling; Molecular Conformation; Monoclonal Antibodies; Monoclonal Antibody Therapy; Mus; Mutation; Peptides; Pharmaceutical Preparations; Plasma; Positioning Attribute; Prevention therapy; Primate Lentiviruses; Property; Proteins; Reporting; Resistance; Resources; Societies; Solubility; Specificity; Stretching; Structure; Technology; Testing; Therapeutic; Time; Toxic effect; Treatment Efficacy; Vaccines; Variant; Viral; Viral load measurement; Viremia; Virus; Virus Replication; antibody inhibitor; base; complementarity-determining region 3; experience; falls; immunogenic; improved; inhibitor/antagonist; meetings; molecular size; neutralizing antibody; novel; novel strategies; novel therapeutics; receptor; response; simian human immunodeficiency virus; therapeutic vaccine

The major accomplishments for this year are summarized below: 1) Neutralizing antibodies that target the membrane-proximal external region (MPER) of the HIV-1 gp41 glycoprotein fall into two classes, depending on whether they target the N-terminus of the MPER or its C-terminus. The antibody m66 and its more potent variant m66.6, as well as antibody 2F5, represent the only neutralizing antibodies known to target the N-terminus of the gp41 MPER. Our collaborators solved the crystal structure of m66 in complex with its gp41 epitope, as well as the free structures of m66 and m66.6. When bound by m66, the N-terminus of the gp41 MPER adopts a conformation composed of a helix followed by a strand. Comparison of m66 recognition of gp41 with that of 2F5 reveals similarities in the conformations of shared critical epitope residues, 664DKW666, as well as in the angles by which they approach these residues. A stretch of aromatic residues at the tip of the m66 heavy chain third complementarity determining region (CDRH3) loop is positioned along the same plane formed by functional hydrophobic residues at the tip of the 2F5 CDRH3. Mutation of these aromatic residues in the m66.6 context, to either increase or decrease hydrophobicity, dramatically altered m66.6 neutralization of HIV-1 and its recognition of the MPER in a lipid context, but had little effect on its recognition of a soluble MPER peptide. The similarities observed between antibodies m66 and 2F5 thus suggest that both antibodies have converged on common structural and mechanistic elements in recognition and neutralization of HIV-1. 2) By combining a protein cavity-filling strategy and the power of library technology, we further improved mD1.2 identifying an engineered cavity-altered single-domain sCD4 (mD1.22) with a unique combination of excellent properties including broad and potent neutralizing activity, high specificity, stability, solubility, and affinity for the HIV-1 envelope glycoprotein gp120, and small molecular size. To further improve its neutralizing potency and breadth, we generated bispecific multivalent fusion proteins of mD1.22 with another potent HIV-1 inhibitor - an antibody domain (m36.4) targeting the coreceptor-binding site on gp120. The fusion proteins neutralized all HIV-1 isolates tested with potency about 10-, 50-, and 200-fold higher than that of the broadly neutralizing antibody VRC01, the US FDA-approved peptide inhibitor T20, and the clinically tested sCD4-Fc fusion protein CD4-Ig, respectively. In addition, they exhibited higher stability and specificity, and lower aggregation propensity than CD4-Ig. Therefore, mD1.22 and related fusion proteins could be potentially useful for HIV-1 prevention and therapy including eradication of the virus. 3) We also analyzed the potency of potent bnAbs in a macaque model of HIV-1 infection. Neutralizing antibodies can confer immunity to primate lentiviruses by blocking infection in macaque models of AIDS. However, earlier studies of anti-human immunodeficiency virus type 1 (HIV-1) neutralizing antibodies administered to infected individuals or humanized mice reported poor control of virus replication and the rapid emergence of resistant variants. A new generation of anti-HIV-1 monoclonal antibodies, possessing extraordinary potency and breadth of neutralizing activity, has recently been isolated from infected individuals. Our collaborators have examined two of the new antibodies, directed to the CD4-binding site and the V3 region (3BNC117 and 10-1074, respectively), for their ability to block infection and suppress viraemia in macaques infected with the R5 tropic simian-human immunodeficiency virus (SHIV)-AD8, which emulates many of the pathogenic and immunogenic properties of HIV-1 during infections of rhesus macaques. Either antibody alone can potently block virus acquisition. When administered individually to recently infected macaques, the 10-1074 antibody caused a rapid decline in virus load to undetectable levels for 4-7 days, followed by virus rebound during which neutralization-resistant variants became detectable. When administered together, a single treatment rapidly suppressed plasma viraemia for 3-5 weeks in some long-term chronically SHIV-infected animals with low CD4(+) T-cell levels. A second cycle of anti-HIV-1 monoclonal antibody therapy, administered to two previously treated animals, successfully controlled virus rebound. I did computational analysis of the slopes of viral decline as a predictor of the therapy efficacy and found the important result that it is the same as for humans treated with HAART which we showed previously is a strong predictor of efficacy (67). These results indicate that immunotherapy or a combination of immunotherapy plus conventional antiretroviral drugs might be useful as a therapy for chronically HIV-1-infected individuals experiencing immune dysfunction.

今年的主要成就总结如下：1）针对HIV-1 GP41糖蛋白的膜外部区域（MPER）中和抗体的中和抗体分为两个类别它的C末端。抗体M66及其更有效的变体M66.6以及抗体2F5代表了唯一已知的中和抗体，它靶向GP41 MPer的N末端。我们的合作者解决了M66与其GP41表位的晶体结构，以及M66和M66.6的自由结构。当由M66绑定时，GP41 MPer的N末端会采用由螺旋组成的构象，其次是链。 M66对GP41识别与2F5的识别的比较揭示了共享临界表位残基的构象相似之处，即664DKW666，以及它们接近这些残基的角度。在M66重链尖端的一系列芳族残基确定区域（CDRH3）回路沿着由功能性疏水残基形成的同一平面位于2F5 CDRH3的尖端。这些芳香族残基在M66.6环境中的突变，以增加或降低疏水性，大大改变了HIV-1的M66.6中和HIV-1及其在脂质环境中对MPER的识别，但对其可溶性的识别几乎没有影响MPER肽。因此，观察到的抗体M66和2f5之间的相似性表明，两种抗体在识别和中和HIV-1中的常见结构和机械元件上都融合了。 2）通过将蛋白质腔填充策略和图书馆技术的力量相结合，我们进一步改善了MD1.2确定了工程化的腔体改变的单域SCD4（MD1.22），以及独特的优秀特性组合，包括广泛而有效的中和HIV-1包膜糖蛋白GP120和小分子大小的活性，高特​​异性，稳定性，溶解度和亲和力。为了进一步提高其中和效力和广度，我们与另一种有效的HIV-1抑制剂 - 一种抗体结构域（M36.4）产生了MD1.22的双特异性多价融合蛋白，该抗体结构域（M36.4）靶向GP120上的肌受感受器结合位点。融合蛋白中和所有用效力测试的所有HIV-1分离株比广泛中和抗体VRC01，美国FDA批准的肽抑制剂T20和临床测试的SCD4-FC融合量高约10、50和200倍。蛋白CD4-Ig分别。此外，它们表现出比CD4-Ig更高的稳定性和特异性，聚集倾向更低。因此，MD1.22和相关的融合蛋白可能对HIV-1预防和治疗可能有用，包括消除病毒。 3）我们还分析了HIV-1感染的猕猴模型中有效BNAB的效力。中和抗体可以通过阻断猕猴艾滋病模型中的感染来赋予灵长类动病毒免疫。然而，早期对抗人免疫缺陷病毒1型（HIV-1）中和对感染个体或人源性小鼠施用的抗体的研究表明，对病毒复制的控制不良和抗性变异的迅速出现。最近已经从感染的个体中分离出了新一代的抗HIV-1单克隆抗体，具有非凡的效力和中和活性的广度。我们的合作者检查了针对CD4结合站点和V3区域（分别为3 bnc117和10-1074）的两种新抗体，因为它们能够阻止感染和抑制R5热带Simian-Human-Human感染的猕猴感染和抑制病毒血症的能力免疫缺陷病毒（SHIV）-AD8，该病毒在恒河猕猴感染期间模仿HIV-1的许多致病性和免疫原性。单独的任何一种抗体都可以有效阻止病毒的获取。当分别对最近感染的猕猴分别施用时，10-1074抗体在4-7天内导致病毒载荷迅速下降至无法检测的水平，然后病毒反弹，在此期间可检测到中和抗性变体。当一起给药时，在一些长期慢性湿透的动物中，单一治疗迅速抑制血浆病毒血症3-5周，CD4（+）T细胞水平较低。第二个抗HIV-1单克隆抗体治疗的周期，该抗体治疗对两种先前治疗的动物进行了成功控制的病毒反弹。我对病毒下降的斜率进行了计算分析，作为治疗功效的预测指标，发现它与接受HAART治疗的人相同的重要结果，我们以前所展示的是功效的有力预测指标（67）。这些结果表明，免疫疗法或免疫疗法加常规抗逆转录病毒药物的结合可能是一种用于慢性HIV-1感染的患者患有免疫功能障碍的疗法。