Development of a novel adjuvant strategy enabled by modulation of the physical properties of fungal mannans

项目总结 疫苗是保护个人免受传染病侵袭的一种非常有效的公共卫生措施。许多 疫苗的工作原理是诱导抗原特异性抗体，中和病原体或其产物，促进 他们的许可。基于蛋白质抗原的疫苗通常需要添加佐剂来增强 抗原特异性适应性免疫反应的效力、广度和持续时间。佐剂促进疫苗 通过激活称为模式识别受体的先天免疫系统受体来实现抗原免疫原性 (PRRS)和/或调节抗原药代动力学。铝盐是FDA最常见的佐剂- 批准的疫苗。最近，包括针对特定PRR的佐剂的疫苗，特别是类似Toll的疫苗 受体(TLR)4和TLR9也已获得FDA的批准，为开发 分子定义的佐剂。研究额外的PRR作为佐剂靶点的潜力至关重要 重要的是要扩展我们的疫苗工具箱，并探索不同的天然免疫细胞激活方式 影响适应性免疫反应。在这里，我们建议使用严重急性呼吸综合征 以冠状病毒2型(SARS-CoV-2)刺突蛋白为模型抗原，测试一种新的佐剂制剂，该制剂含有 靶向PRR Dectin-2的真菌配体。我们的初步结果表明，甘露聚糖(真菌细胞壁 从白色念珠菌中分离出的多糖)单独或与氢氧化铝配伍可增强 融合前的免疫原性稳定，Spike三聚体在小鼠模型中免疫。尤其是曼南 与仅使用氢氧化铝相比，配方会导致早期的抗尖峰抗体水平上升， 增强SARS-CoV-2中和抗体的诱导，拓宽靶向的尖峰表位 并且有利于向免疫球蛋白亚类的转变，这些亚类与更高的效应器功能和更少的免疫球蛋白相关 疫苗相关增强型呼吸道疾病(VAERD)的风险。在这里我们假设甘露糖 氢氧化铝制剂诱导对SARS-CoV-2刺突的有效和持久的适应性免疫反应 通过诱导特定的先天免疫途径和激活程序。通过将详细的 免疫原性和机制分析，我们的建议将定义一种新的佐剂配方 SARS-CoV-2 Spike和潜在的其他病毒糖蛋白，以及对SARS-CoV-2毒株生物学的新认识 Dectin-2。

PROJECT SUMMARY Vaccines represent a highly effective public health measure to protect individuals from infectious diseases. Many vaccines work by inducing antigen-specific antibodies that neutralize the pathogen or its products and promote their clearance. Vaccines based on protein antigens usually require the addition of adjuvants to enhance potency, breadth and duration of the antigen-specific adaptive immune response. Adjuvants promote vaccine antigen immunogenicity by activating receptors of the innate immune system called pattern-recognition receptors (PRRs) and/or modulating antigen pharmacokinetics. Aluminum salts are the most common adjuvants in FDA- approved vaccines. Recently, vaccines including adjuvants that target specific PRRs, in particular toll-like receptor (TLR)4 and TLR9, have also been approved by the FDA, paving the way for the development of molecularly defined adjuvants. Investigating the potential of additional PRRs as adjuvant targets is of paramount important to expand our vaccine toolbox and probe how different modalities of innate immune cell activation impact the adaptive immune response. Here, we propose to use the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Spike protein as a model antigen to test a new adjuvant formulation that contains fungal ligands that target the PRR Dectin-2. Our preliminary results show that mannans (fungal cell wall polysaccharides isolated from Candia albicans) alone or formulated with aluminum hydroxide enhance the immunogenicity of pre-fusion stabilized, Spike trimers in mouse models of immunization. In particular, mannan formulations, compared to aluminum hydroxide only, induce an early increase in anti-Spike antibody levels, potentiate the induction of SARS-CoV-2 neutralizing antibodies, broaden the Spike epitopes that are targeted and favor the switch towards immunoglobulin subclasses associated with higher effector functions and reduced risk of vaccine-associated enhanced respiratory disease (VAERD). Here we hypothesize that mannans formulated with alumOH induce a potent and durable adaptive immune response to SARS-CoV-2 Spike by inducing specific innate immune pathways and activation programs. By combining detailed immunogenicity and mechanistic analyses, our proposal will define a novel adjuvant formulation for SARS-CoV-2 Spike and potentially other viral glycoproteins as well as shed new light on the biology of Dectin-2.