PA-22-176, SBIR, Phase I, Novel Bispecific Nanotherapeutics as Broad-Spectrum Influenza Antivirals Refractory to Viral Escape

项目摘要 自20世纪初以来，甲型流感病毒（IAV）已经引起了四次大流行。1918-1919年 “西班牙流感”是最严重的，据估计已造成全球5000多万人死亡。一 面对下一次大流行的快速反应取决于是否有预先部署的医疗 对抗措施，包括疫苗和治疗。这些医疗干预措施处于不断的军备竞赛中 快速进化的IAV毒株使用多种策略来逃避它们。流感的分段基因组 当两种IAV毒株感染同一细胞时，病毒可以重新分类，从而在一个过程中产生新的毒株 称为抗原性转变。这些新的菌株，最常见的是在鸟类水库，一直归咎于每一个 人类可能没有预先存在的免疫力。此外，病毒性的易出错 聚合酶驱动抗原漂移，允许响应选择压力的突变快速积累， 有效地逃避宿主的免疫反应或抗病毒药物。抗原漂移推动了 对FDA批准的六种抗病毒药物中的每一种都有耐药性的多种菌株，并强调了 新一代的治疗方法免疫治疗是有效的抗病毒对策，可以仔细 设计时考虑到了流感规避策略。首先，在许多不同的表位中高度保守的表位， 在多个宿主中传播的IAV毒株不太可能耐受耐药突变，使其成为一种流行病。 抗病毒分子的合适靶点。第二，结合两个不同表位的双特异性分子可以是 用于降低完全逃逸的可能性，并且在某些情况下可以协同作用。与 考虑到下一代IAV免疫系统的这些理想特性，我们建议开发一种新的 在另一个实施方案中，本发明涉及靶向高度保守的血凝素（HA）茎和基质2胞外域（M2 e）的双特异性分子。 我们的方法利用了一类新的免疫疗法-ODIN（正交双向相互作用） Nanostim）平台-将两种天然免疫序列库组合成单域 双特异性分子。ODIN分子将骆驼VHH与超长CDR 3（UL-CDR 3）无缝融合 在牛免疫球蛋白重链的亚组中发现，以产生“小而长”的双特异性。的 小的尺寸允许ODIN分子接近IAV屏蔽免疫的表位，如HA茎和M2 e， 通过糖基化和病毒膜附近的空间定位进行监视。ODIN也可以定制， 提供不同的作用机制。为了产生IAV ODIN分子，我们将用 不同IAV毒株和重组蛋白的组合以引发广谱UL-CDR 3。领先的UL- CDR 3将与互补的VHH组合，产生将被评估的ODIN候选物的子集。 对于IAV中和的广度和效力以及抵抗病毒逃逸的产生的能力。率先 从这些研究中出现的候选人将被追求作为下一代IAV免疫和预- 为下一次流感大流行做好部署准备。

Project Summary Influenza A viruses (IAVs) have caused four pandemics since the turn of the 20th century. The 1918-1919 “Spanish Flu” was the most severe and is estimated to have caused more than 50 million deaths worldwide. A rapid response in the face of the next pandemic depends on the availability of pre-positioned medical countermeasures, including vaccines and therapeutics. These medical interventions are in a constant arms race with rapidly evolving IAV strains that use multiple strategies to escape them. The segmented genome of influenza viruses can reassort when two IAV strains infect the same cell, allowing generation of novel strains in a process called antigenic shift. These new strains, most often arising in an avian reservoir, have been to blame for each of the previous pandemics as humans may have no preexisting immunity. Additionally, the viral error-prone polymerase drives antigenic drift, allowing rapid accumulation of mutations in response to selective pressure to effectively escape the host immune response or antiviral medications. Antigenic drift has driven the emergence of multiple strains that are resistant to each of the six FDA-approved antivirals and underscores the need for next-generation therapeutics. Immunotherapeutics are effective antiviral countermeasures and can be carefully designed with flu evasion strategies in mind. First, epitopes that are highly conserved among the many different IAV strains circulating in multiple hosts are less likely to tolerate resistance mutations, making them an appropriate target for antiviral molecules. Second, bispecific molecules that bind to two distinct epitopes can be employed to decrease the likelihood of complete escape, and in some cases can function synergistically. With these ideal properties of a next-generation IAV immunotherapeutic in mind, we propose to develop a novel bispecific molecule targeting the highly conserved hemagglutinin (HA) stalk and the matrix 2 ectodomain (M2e). Our approach leverages a new class of immunotherapeutics—the ODIN (Orthogonal Dual-Interacting Nanotherapeutic) platform—that combines two natural immune sequence repertoires into single-domain bispecific molecule. ODIN molecules seamlessly merge camelid VHHs with the ultra-long CDR3s (UL-CDR3s) found in a subset of bovine immunoglobulin heavy chains to create a “small with a long reach” bispecific. The small size allows ODIN molecules to access epitopes like the HA stalk and M2e that IAV shields from immune surveillance with glycosylation and spatial localization near the viral membrane. ODINs can also be tailored to provide different mechanisms of action. To generate IAV ODIN molecules, we will immunize cattle with a combination of divergent IAV strains and recombinant proteins to elicit broad-spectrum UL-CDR3s. The lead UL- CDR3s will be combined with complimentary VHHs, yielding a subset of ODIN candidates that will be evaluated for IAV neutralization breadth and potency and the ability to resist the generation of viral escapes. The lead candidate emerging from these studies will be pursued as a next-generation IAV immunotherapeutic and pre- positioned for deployment in the next influenza pandemic.