Multidimensional antibody engineering to enhance the potency and breadth of a betacoronavirus medical countermeasure

正在进行的新冠肺炎大流行的规模和持续时间突显了有必要 拥有装备精良的-理想情况下是预先设置的-反病毒武器武器库，以安装 适当的公共卫生应对措施。一个重要的教训是，多种医学对策(MCM) 是在面对快速进化的病毒时保持效力和效力所必需的。几个 批准的SARS-CoV-2疫苗对控制疫情至关重要， 减少全球大部分人口的感染数量和疾病严重程度。 不幸的是，这些疫苗对免疫受损的人几乎没有保护作用。 他们无法产生有效的免疫反应。延长半衰期的单抗 (单抗)提供了一种有吸引力的替代方案，因为它们的半衰期长，效力高，瞬间就能产生 免疫和类似疫苗的保护，不需要产生强大的免疫 回应。在这门课程中，我们探索了10,000种单抗和多种单抗鸡尾酒。 以及几个先进的候选治疗药物，他们在很大程度上未能 面对SARS-CoV-2尖峰内普遍存在的抗原漂移，保持有效的活性 蛋白。此外，目前批准的疫苗和免疫疗法并不提供预防 一种相关的b-CoV，中东呼吸综合征(MERS)病毒。而小分子抑制剂 如帕昔洛韦等在体外表现出了广泛的抗SARS和MERS活性，这是一个重大问题 随着新冠肺炎的反弹，以下治疗表明它可能对 更致命的MERS病毒。最近发现的抗体1249A8(更名为AR-703)， 识别冠状病毒尖峰S2区的一个独特且高度保守的表位 蛋白质提供了一种潜在的解决方案，它对抗原漂移不起作用，并具有广泛的活性。 冠状病毒活动，包括SARS和MERS。该提案的目标是最大限度地提高临床 AR-703通过基于多维结构的方法提高中和度的应用 AR-703的效力和扩展广度。同时，双特异性抗体工程利用一种 将探索基于牛超长CDR3(UL-CDR3)的新型双特异性平台技术 引入协同中和，抵抗病毒逃逸。牛UL-CDR3的结构 有能力独立瞄准神秘的高度保守的表位，这对 保持对新病毒变种的疗效。将AR-703和PAN-b-CoV UL-CDR3组合成一个 单一的双特异性将使高度保守的中和表位的双重参与成为可能 一种有效的解决SARS2抗原漂移的方法，既能保护免疫受损的人 如果相关的致命b-Cov未来出现的话。

The magnitude and duration of the ongoing COVID-19 pandemic have underscored the need to have a well-equipped—and ideally prepositioned—arsenal of antiviral weapons to mount an adequate public health response. A key lesson is that multiple medical countermeasures (MCMs) are needed to maintain potency and efficacy in the face of a rapidly evolving virus. Several approved SARS-CoV-2 vaccines have been paramount to gaining control over the pandemic, reducing both the number of infections and severity of disease for much of the global population. Unfortunately, these vaccines provide little to no protection to immunocompromised individuals who are unable to mount an effective immune response. Half-life extended monoclonal antibodies (mAbs) offer an attractive alternative, as their long half-life and high potency offer instantaneous immunity and vaccine-like protection without requiring the generation of a robust immune response. While >10,000 mAbs and multiple mAb cocktails have been explored over the course of the pandemic and several advanced as therapeutic candidates, they have largely failed to maintain potent activity in the face of prevalent antigenic drift within the SARS-CoV-2 spike protein. Moreover, currently approved vaccines and immunotherapeutics offer no protection from a related b-CoV, Middle East respiratory syndrome (MERS) virus. While small molecule inhibitors such as Paxlovid have shown broad in vitro activity against SARS and MERS, significant issues with COVID-19 rebound following treatment suggest it may not remain efficacious against the more lethal MERS virus. A recently identified antibody, 1249A8 (renamed AR-703), that recognizes a unique and highly conserved epitope in the S2 domain of the coronavirus spike protein offers a potential solution, being refractory to antigenic drift and having broad activity b- CoV activity, inclusive of SARS and MERS. The goal of the proposal is to maximize the clinical utility of AR-703 through multidimensional structure-based approach to increase neutralization potency and expand breadth of AR-703. In parallel, bispecific antibody engineering utilizing a novel bovine ultra-long CDR3 (UL-CDR3) based bispecific platform technology will be explored to introduce synergistic neutralization and resist viral escape. The structures of bovine UL-CDR3s have a demonstrated ability to independently target cryptic highly conserved epitopes, vital to maintaining efficacy to novel viral variants. Combining AR-703 and pan-b-CoV UL-CDR3 into a single bispecific would enable dual engagement of highly conserved neutralizing epitopes offering a potent solution to SARS2 antigenic drift for the immunocompromised while also guarding against related lethal b-CoVs should they emerge in the future.