Antibody therapeutics against biodefense-related diseases

针对生物防御相关疾病的抗体疗法

• 批准号: 8937984
• 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/8937984
• 关键词: Address; Affinity; Animal Model; Animals; Antibodies; Antibody Therapy; Antigens; Avidity; Binding; Binding Sites; Cercopithecus pygerythrus; Clinical; Communicable Diseases; Complex; Coronavirus; Coronavirus Infections; Dengue Virus; Diagnosis; Dipeptidyl-Peptidase IV; Disease; Dissociation; Docking; Dose; Epitopes; Equilibrium; Exhibits; FDA approved; Family suidae; Glycoproteins; Goals; Hendra Virus; Henipavirus; Human; IgG1; Immune response; Incidence; Infection; Influenza; Influenza A Virus, H7N9 Subtype; Investigational Drugs; Libraries; Life; Measures; Methodology; Microbe; Middle East; Modeling; Monoclonal Antibodies; Nipah Virus; Palivizumab; Paramyxovirus; Prevention; Prophylactic treatment; Reagent; Research; Site-Directed Mutagenesis; Surface; Syndrome; Testing; Therapeutic; Therapeutic antibodies; Time; Toxin; Vaccines; Variant; Viral; Virus; Virus Diseases; base; biodefense; biothreat; coronavirus spike glycoprotein; human monoclonal antibodies; in vitro testing; in vivo; interest; killings; mortality; neutralizing antibody; nonhuman primate; novel; pandemic disease; receptor; receptor binding; research and development; research study; respiratory; response; therapeutic vaccine; tool development; viral RNA

The major accomplishments for this year are summarized below. 1) Nipah virus (NiV) is an emerging zoonotic paramyxovirus related to HeV that causes severe and often fatal disease in pigs and humans. There are currently no vaccines or treatments approved for human use. Studies in small-animal models of NiV infection suggest that antibody therapy may be a promising treatment. However, most studies have assessed treatment at times shortly after virus exposure before animals show signs of disease. The efficacy of the m102.4 was evaluated at several time points after virus exposure including at the onset of clinical illness in a uniformly lethal nonhuman primate model of NiV disease. Sixteen African green monkeys (AGMs) were challenged intratracheally with a lethal dose of NiV, and 12 animals were infused twice with m102.4 (15 mg/kg) beginning at either 1, 3, or 5 days after virus challenge and again about 2 days later. The presence of viral RNA, infectious virus, and/or NiV-specific immune responses demonstrated that all subjects were infected after challenge. All 12 AGMs that received m102.4 survived infection, whereas the untreated control subjects succumbed to disease between days 8 and 10 after infection. AGMs in the day 5 treatment group exhibited clinical signs of disease, but all animals recovered by day 16. These results represent the successful therapeutic in vivo efficacy by an investigational drug against NiV in a nonhuman primate. Overall these results and previous results from animal studies and 12 humans administered with this mAb confirm our proposition that m102.4 has potential as a therapeutic for treatment of diseases caused by henipaviruses, and could save human lives now. It could be also used for prophylaxis, diagnosis and as a research reagent. 2) The recently discovered Middle East Respiratory Syndrome Coronavirus (MERS-CoV) continues to infect humans with high mortality. Specific, highly effective therapeutics and vaccines against the MERS-CoV are urgently needed to safe human lives and address the pandemic concerns. We identified three human monoclonal antibodies (mAbs), m336, m337 and m338, targeting the receptor (CD26/DPP4) binding domain (RBD) of the MERS-CoV spike glycoprotein from a very large (size 1011) naive human antibody library. They bound with high affinity - equilibrium dissociation constants equal to 4.2, 9.3 and 15 nM, respectively, as measured by Biacore for Fabs binding to RBD. The avidity for IgG1 m336, m337 and m338 as measured by Biacore was even higher - 99, 820 and 560 pM, respectively. The antibodies bound to overlapping epitopes which overlap with the receptor binding site on the RBD as suggested by competition experiments, and further supported by site directed mutagenesis of the RBD and a docking model of the m336-RBD complex. The highest affinity mAb, m336, neutralized both pseudotyped and live MERS-CoV with exceptional potency: 50% neutralization at 0.005 and 0.07 ug/ml, respectively, likely by competing with DPP4 for binding to the S glycoprotein. The exceptionally high neutralizing activity of these antibodies and especially m336 suggest that they have great potential for prophylaxis and therapy of MERS-CoV infection in humans and a tool for development of vaccine immunogens. The rapid (several weeks) identification of three potent mAbs suggests a possibility to use the new large antibody library and related methodology for quick response to public threat resulting from emerging coronaviruses.

现将今年以来的主要工作成果总结如下。 1) 尼帕病毒 (NiV) 是一种与 HeV 相关的新兴人畜共患副粘病毒，可导致猪和人类严重且往往致命的疾病。目前还没有批准用于人类使用的疫苗或治疗方法。对 NiV 感染小动物模型的研究表明，抗体疗法可能是一种有前途的治疗方法。然而，大多数研究都是在动物暴露于病毒后不久、动物出现疾病迹象之前评估治疗。 m102.4 的功效在病毒暴露后的几个时间点进行了评估，包括在一致致死的非人灵长类 NiV 疾病模型中临床疾病发作时。 16 只非洲绿猴 (AGM) 接受致死剂量的 NiV 气管内攻击，12 只动物在病毒攻击后 1、3 或 5 天开始两次注射 m102.4 (15 mg/kg)，并在约 2 天再次注射。几天后。病毒RNA、传染性病毒和/或NiV特异性免疫反应的存在表明所有受试者在攻击后都被感染。所有接受 m102.4 的 12 名 AGM 均在感染后存活下来，而未经治疗的对照受试者则在感染后 8 至 10 天之间死于疾病。第 5 天治疗组中的 AGM 表现出疾病的临床症状，但所有动物在第 16 天都恢复了。这些结果代表了一种针对 NiV 的研究药物在非人类灵长类动物中取得了成功的体内治疗效果。总体而言，这些结果以及之前对动物研究和 12 名使用该 mAb 的人进行的研究结果证实了我们的观点，即 m102.4 有潜力作为治疗亨尼帕病毒引起的疾病的药物，并且现在可以挽救人类的生命。它还可用于预防、诊断和作为研究试剂。 2）最近发现的中东呼吸综合症冠状病毒（MERS-CoV）继续感染人类，死亡率很高。为了保护人类生命安全并解决大流行问题，迫切需要针对中东呼吸综合征冠状病毒的特异性、高效疗法和疫苗。我们从一个非常大（大小 1011）的天然人类抗体库中鉴定出三种人类单克隆抗体（mAb）：m336、m337 和 m338，它们针对 MERS-CoV 刺突糖蛋白的受体（CD26/DPP4）结合域（RBD）。它们以高亲和力结合，平衡解离常数分别等于 4.2、9.3 和 15 nM，通过 Biacore 测量 Fab 与 RBD 的结合。通过 Biacore 测量，IgG1 m336、m337 和 m338 的亲合力甚至更高，分别为 99、820 和 560 pM。正如竞争实验所表明的，抗体与重叠表位结合，这些表位与 RBD 上的受体结合位点重叠，并得到 RBD 定点诱变和 m336-RBD 复合物对接模型的进一步支持。亲和力最高的 mAb m336 以非凡的效力中和假型和活的 MERS-CoV：分别在 0.005 和 0.07 ug/ml 时中和 50%，可能是通过与 DPP4 竞争与 S 糖蛋白的结合来实现的。这些抗体（尤其是 m336）的极高中和活性表明它们在预防和治疗人类 MERS-CoV 感染方面具有巨大潜力，并且可以作为开发疫苗免疫原的工具。三种强效单克隆抗体的快速（几周）鉴定表明有可能使用新的大型抗体库和相关方法来快速应对新兴冠状病毒造成的公共威胁。