Rapid Response Vaccines for Botulinum Neurotoxins

描述（由申请人提供）：肉毒杆菌神经毒素（BoNTs）是已知最有效的蛋白质毒素。鉴于其强大的毒性和在生物战场景中的潜在用途，bont被列入A类选定剂。目前可用的五价类毒素疫苗需要多次加强剂才能有效，并且对不同BoNT血清型的保护不平等。目前迫切需要BoNT疫苗，以便在暴露于BoNT威胁迫在眉睫的情况下产生快速保护，并对多价疫苗的每个组成部分提供有效的免疫反应。为了实现对Hc的快速和更强的免疫应答，我们寻求将Hc抗原与R4连接的策略，R4是我们开发的一种新型佐剂，可有效地将疫苗抗原加载到树突状细胞（dc）上。通过将Hc抗原特异性靶向dc，加速了免疫反应的关键早期步骤。我们已经将BoNT/A Hc作为R4的融合蛋白来表达以产生HcR4，并且已经证明HcR4对BoNT/A Hc抗原诱导的免疫反应比单独使用Hc抗原更快速和强大。基于这些结果，我们假设可以利用HcR4融合蛋白开发一种有效的针对bont的快速多价疫苗。这一项目的目标是推进新型BoNT疫苗的开发，这是对当前疫苗技术的重大改进。拟议的研究将通过开发用于BoNT血清型B和E的HcR4配体来实现这些目标，这些配体将与已经生产和表征的BoNT/A HcR4作为多价疫苗联合使用。我们将测试这种多价疫苗作为单剂量或多剂量肠外注射疫苗是否能对bont产生快速和保护性的免疫反应。此外，多价BoNT疫苗将作为粘膜疫苗进行测试，以产生对BoNT的全身和粘膜免疫反应。该项目将实现HcR4配体开发的下一个里程碑：1)我们将开发用于BoNT血清型B和E的HcR4免疫原，与已经开发和表征的BoNT/A HcR4联合使用。2)我们将确定多价HcR4疫苗作为快速保护疫苗、一针疫苗和多剂量疫苗的有效性；3)确定粘膜/鼻腔给药HcR4是否能快速诱导针对bont的全身和粘膜抗体反应。这些研究旨在提供足够的原理证明，以推进多价BoNT疫苗进入临床开发。在目前的研究中获得的专门知识将有助于未来开发针对其他毒素和传染原的新型和改进的疫苗。

DESCRIPTION (provided by applicant): Botulinum neurotoxins (BoNTs) are the most potent protein toxins known. Given their potent toxicity and their potential use in bio-warfare scenarios, BoNTs are included among the Category A select agents. The currently available pentavalent toxoid vaccine requires multiple boosters before being effective, and protects unequally against the different BoNT serotypes. There is a critical need for BoNT vaccines that will induce rapid protection in situations where the threat of BoNT exposure is imminent as well as to provide effective immune responses to each constituent of a multivalent vaccine. To achieve rapid and more robust immune responses to Hc we have pursued a strategy of linking Hc antigens to R4, a novel adjuvant developed by us that efficiently loads vaccine antigens onto dendritic cells (DCs). By specifically targeting the Hc antigen to DCs, the critical early steps in the immune response are hastened. We have expressed BoNT/A Hc as a fusion protein with R4 to produce HcR4 and have demonstrated that HcR4 induces more rapid and robust immune responses to BoNT/A Hc antigen than can be achieved using the Hc antigen alone. Based on these results we hypothesize that an effective rapid- acting multivalent vaccine against BoNTs can be developed using HcR4 fusion proteins. The goal of this project is to advance the development of a new class of BoNT vaccines that represent a significant improvement over current vaccine technologies. The proposed studies will achieve these goals through development of HcR4 ligands for BoNT serotypes B and E for use in combination with the already produced and characterized BoNT/A HcR4 as a multivalent vaccine. We will test whether this multivalent vaccine can generate rapid and protective immune responses to BoNTs when administered as a single or multidose parenteral vaccine. In addition, the multivalent BoNT vaccine will be tested as a mucosal vaccine for the generation of systemic and mucosal immune responses to BoNT. This project will achieve the next milestones in the development of the HcR4 ligands: 1) We will develop HcR4 immunogens for BoNT serotypes B and E for use in combination with the already developed and characterized BoNT/A HcR4. 2) We will establish the efficacy of a multivalent HcR4 vaccine as a rapid- protection, one-shot vaccine, and as a multi-dose vaccine, and; 3) Determine if mucosal/nasal administration of HcR4 can result in the rapid induction of systemic and mucosal antibody responses against BoNTs. These studies are intended to deliver sufficient proof-of-principle for advancing the polyvalent BoNT vaccine into clinical development. The know-how gained in the current studies will be useful in the future for development of novel and improved vaccines to other toxins and infectious agents.