A muco-penetrating biomaterial-based subunit vaccine for programming protective immune responses to SARS-CoV-2

1.摘要/摘要 鉴于SARS-CoV-2的进入部位是呼吸道粘膜，有效的SARS-CoV-2疫苗应该是 启动体液和呼吸道粘膜免疫反应。尽管鼻腔亚单位疫苗将是一种 SARS-CoV-2的理想平台，跨鼻粘膜运输，缺乏安全有效的粘膜疫苗 佐剂阻碍了临床可行的鼻腔亚单位疫苗的开发。我们建议发展一种鼻腔内 由SARS-CoV-2蛋白与免疫刺激生物材料结合组成的疫苗 鼻黏膜的运输障碍，从而诱导保护性黏膜和系统免疫。我们的平台是 由SARS-CoV-2受体结合结构域部分(RBD)连接到水溶性聚合物组成，称为 MPGAP是由结合鼻粘液的单体合成的，它破坏了大腿内皮连接，并靶向和 激活抗原提呈细胞(APC)。因此，在鼻腔给药时，RBD-MPGAP结合物应该(1) 黏附鼻腔粘液，增加鼻腔上皮停留时间，(2)拆除紧密连接，最大限度地 (3)靶向结合RBD并激活 APC，激发APC衍生的信号，激活T细胞和B细胞。通过克服鼻腔的生物障碍 RBD-MPGAP对内皮细胞和免疫刺激因子靶向免疫细胞的保护作用 以及在没有脱靶效应的情况下的系统免疫力。RBD-MPGAP偶联物将被生产、表征和 它们结合鼻腔粘液、增强细胞旁运输以及靶向和激活抗原提呈细胞的能力将是 在老鼠身上进行了测试。RBD-MPGAP免疫小鼠血清和呼吸液中和抗体滴度 通过体外SARS-CoV-2中和试验进行评估。最后，防腐剂的保护效果和耐用性 将在SARS-CoV-2小鼠模型上研究RBD-MPGAP鼻腔注射诱导的黏膜和系统免疫。 该项目的完成将验证鼻腔注射SARS-CoV-2亚单位疫苗的临床前疗效，并提供 一个可以抗击从季节性流感到下一种呼吸道病毒等众多其他呼吸道感染的平台 大流行。

1. ABSTRACT/SUMMARY Given that the site of entry of SARS-CoV-2 is the respiratory mucosa, an effective vaccine for SARS-CoV-2 should initiate both humoral and respiratory mucosal immune responses. Although an intranasal subunit vaccine would be an ideal platform for SARS-CoV-2, transport across the nasal mucosa and a lack of safe and effective mucosal vaccine adjuvants thwart the development of a clinically-viable intranasal subunit vaccine. We propose to develop an intranasal vaccine composed of SARS-CoV-2 proteins conjugated to an immunostimulatory biomaterial that overcomes the transport barriers of the nasal mucosa and thus induces protective mucosal and systemic immunity. Our platform is composed of SARS-CoV-2 receptor-binding domain portion (RBD) conjugated to water-soluble polymers, termed MPGAP, that are synthesized from monomers that bind nasal mucus, disrupt endothelial thigh junctions, and target and activate antigen presenting cells (APCs). Thus, when administered intranasally, RBD- MPGAP conjugates should (1) adhere to nasal mucus, increasing residency time at the nasal epithelium, (2) dismantle tight junctions, maximizing paracellular transport to underlying APCs and nasal associated lymphoid tissue, (3) target conjugated RBD to and activate APCs, eliciting APC-derived signals that activate T and B cells. By overcoming the biological barriers of the nasal endothelium and targeting immunostimulatory factors to immune cells, RBD- MPGAP should induce protective mucosal and systemic immunity in the absence of off-target effects. RBD-MPGAP conjugates will be produced, characterized, and their ability to bind nasal mucus, enhance paracellular transport, and target and activate antigen presenting cells will be tested in mice. The neutralizing antibody titer of serum and respiratory fluids from RBD-MPGAP-immunized mice will be assessed via an in-vitro SARS-CoV-2 neutralization assay. Finally, the protective efficacy and durability of the mucosal and systemic immunity elicited by internasal RBD-MPGAP will be investigated in a SARS-CoV-2 mouse model. Completion of this project will validate the preclinical efficacy of an intranasal SARS-CoV-2 subunit vaccine and deliver a platform that could combat numerous other respiratory infections, from seasonal influenza to the next respiratory viral pandemic.