Development of a bioconjugate vaccine against Group B Streptococcus

项目摘要 无乳链球菌，通常称为B族链球菌（GBS），是新生儿腹泻的主要原因。 脑膜炎和败血症，以及孕妇和非孕妇的侵袭性疾病的病原体 成年人了GBS新生儿疾病表现为早发性，定义为出生后前六天内的疾病，或 迟发性，定义为出生后第一周后发生的疾病;这两种疾病都危及生命。在一些 在某些情况下，早期发病的疾病是可以预防的分娩期抗生素预防;然而，这种治疗， 这一战略对低收入和中等收入国家不切实际，也不能预防晚发性疾病或~3.5 每年有1000万早产和60，000例死产归因于GBS。在分子上，GBS产生十种不同的 荚膜多糖，其中五种（血清型Ia，Ib，II，III和V）与97%的所有侵袭性 新生儿GBS疾病事件。此外，以前的研究表明，胎盘转移的 母体抗体能够保护新生儿免受侵袭性GBS感染。因此，针对这些的疫苗 五种血清型具有很高的社会和商业价值。为了研制针对GBS的有效疫苗， 胶囊，多糖必须共价连接到一个免疫原性载体蛋白产生什么 称为结合疫苗。结合疫苗被认为是迄今为止最有效的疫苗， 它们具有高度保护性，并在所有年龄组中产生免疫记忆。然而，它们的合成 是复杂的、昂贵的，并且不利于所有多糖，这阻碍了新的多糖的开发。 针对危及生命的细菌如GBS的结合疫苗。作为一种替代制造平台， VaxNewMo正在使用创新的体内结合技术开发结合疫苗， 消除了对目前用于合成这些化合物的复杂化学缀合方法的依赖性， 疫苗。使用VaxNewMo专有的生物结合酶技术，我们将因此产生最多的 广泛覆盖针对五种最流行的GBS血清型的GBS疫苗， 侵袭性疾病事件。在第一阶段的申请中，拟议的研究将集中在（目标1）开发五个 糖工程菌株E.在大肠杆菌中进行GBS荚膜多糖的可扩展的重组表达， 与VaxNewMo的结合酶技术相结合，产生了第一个针对 GBS。随后（目的2），我们将证明单价GBS生物缀合物疫苗是 免疫原性不劣于传统制备的化学GBS缀合物疫苗。我们还将 通过提供初步的免疫原性数据证明VaxNewMo生物缀合平台的多功能性 五价GBS生物结合物上最后，我们将通过确定细菌负荷来测试免疫力的相关性 和/或从接种疫苗的小鼠出生的感染GBS的新生幼崽的存活率。第二阶段融资的下一步 将开发和优化大规模GBS生物结合疫苗的纯化方案 并提供足够的安全性、耐受性和免疫原性数据，以获得FDA快速通道批准。

PROJECT SUMMARY Streptococcus agalactiae, commonly referred to as Group B Streptococcus (GBS), is a leading cause of neonatal meningitis and sepsis worldwide as well as an agent of invasive disease in both pregnant and non-pregnant adults. GBS neonatal disease manifests as early onset, defined as disease within the first six days after birth, or late onset, defined as disease occurring after the first week of life; both of which are life threatening. In some instances, early onset disease is preventable with intrapartum antibiotic prophylaxis; however, this treatment strategy is not practical for low- and middle-income countries nor does it prevent late onset disease or the ~3.5 million preterm and 60,000 stillbirths attributed to GBS each year. Molecularly, GBS produces one of ten different capsular polysaccharides, five of which (serotype Ia, Ib, II, III, and V) are associated with 97% of all invasive neonatal GBS disease events. In addition, previous studies have demonstrated that placental transfer of maternal antibodies are able protect neonates from invasive GBS infection. Therefore, a vaccine targeting these five serotypes is of high societal and commercial value. In order to make an efficacious vaccine targeting GBS capsules, the polysaccharide must be covalently linked to an immunogenic carrier protein generating what’s termed a conjugate vaccine. Conjugate vaccines are considered some of the most effective vaccines to date, as they are highly protective and generate immunological memory across all age groups. However, their synthesis is complex, costly, and not conducive for all polysaccharides, which has hindered development of novel conjugate vaccines against life threatening bacteria like GBS. As an alternative manufacturing platform, VaxNewMo is developing conjugate vaccines using an innovative in vivo conjugation technology, which eliminates the dependency on intricate chemical conjugation methods currently employed to synthesize these vaccines. Using VaxNewMo’s proprietary bioconjugating enzyme technology, we will therefore generate the most broadly covering GBS vaccine against five of the most prevalent GBS serotypes causing 97% of all neonatal invasive disease events. The proposed research in this phase I application will focus on (Aim 1) developing five glycoengineered strains of E. coli for the scalable, recombinant expression of GBS capsular polysaccharides in conjunction with VaxNewMo’s conjugating enzyme technology, generating the first bioconjugate vaccine against GBS. Subsequently (Aim 2) we will demonstrate that a monovalent GBS bioconjugate vaccine is immunogenically non-inferior to a traditionally prepared chemical GBS conjugate vaccine. We will also demonstrate the versatility of VaxNewMo’s bioconjugating platform by providing preliminary immunogenicity data on a pentavalent GBS bioconjugate. Last, we will test for correlates of immunity by determining bacterial burden and/or survival of newborn pups infected with GBS born from vaccinated mice. Our next step for Phase II funding will be to develop and optimize a purification protocol for large scale quantities of GBS bioconjugate vaccines and provide sufficient safety, tolerability and immunogenicity data for Fast Track FDA approval.