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。一个 面对下一次大流行的快速反应取决于预先部署的医疗服务的可用性 对策，包括疫苗和疗法。这些医疗干预措施正在不断地进行军备竞赛。 快速进化的IAV毒株使用多种策略逃避它们。流感病毒的片段基因组 当两个IAV毒株感染同一细胞时，病毒可以重新组合，从而在一个过程中产生新的毒株 称为抗原性转移。这些新的菌株，最常出现在禽类宿主中，被归咎于每一种 以前的大流行作为人类可能没有预先存在的免疫力。此外，容易出错的病毒 聚合酶驱动抗原漂移，允许突变快速积累，以响应选择性压力 有效逃脱宿主的免疫反应或抗病毒药物。抗原漂移推动了这种病毒的出现 对FDA批准的六种抗病毒药物中的每一种都具有耐药性的多个菌株，并强调了 下一代治疗学。免疫疗法是有效的抗病毒对策，可以谨慎使用 在设计时考虑到了避免流感的策略。首先，在许多不同的物种中高度保守的表位 在多个宿主中循环的IAV毒株不太可能耐受耐药性突变，使它们成为 作为抗病毒分子的合适靶点。其次，与两个不同表位结合的双特异性分子可以是 用来降低完全逃脱的可能性，在某些情况下可以协同作用。使用 考虑到这些理想的下一代IAV免疫疗法的特性，我们建议开发一种新型的 针对高度保守的血凝素(HA)茎和基质2胞外结构域(M2e)的双特异性分子。 我们的方法利用了一种新的免疫疗法--Odin(正交双相互作用 纳米治疗)平台-将两个天然免疫序列谱系结合到单一结构域中 双特异性分子。ODIN分子将骆驼VHH与超长CDR3(UL-CDR3)无缝融合 发现在牛免疫球蛋白重链的一个子集中形成了一个“小而长达”的双特异性。这个 较小的体积允许ODIN分子访问IAV保护免疫的HA茎和M2e等表位 用糖基化和病毒膜附近的空间定位进行监测。ODINS还可以定制为 提供不同的行动机制。为了产生IAV odin分子，我们将用一种 不同的IAV毒株与重组蛋白结合可诱导广谱UL-CDR3。领先的UL- CDR3将与免费的VHH相结合，产生将被评估的ODIN候选子集 对于IAV的中和广度和效力以及抵抗病毒逃逸的产生的能力。领头羊 从这些研究中脱颖而出的候选人将被视为下一代IAV免疫治疗和前期 为下一次流感大流行部署做好准备。

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.