In vivo conjugated multivalent toxoid-polysaccharide vaccine for S. aureus

描述（由申请方提供）：金黄色葡萄球菌是一种革兰氏阳性人类病原体，可引起从皮肤和软组织感染（SSTI）到危及生命的脓毒症和肺炎的各种感染。S.金黄色葡萄球菌依赖于许多毒力因子，包括细胞表面蛋白和多糖，以及分泌的毒素。这些毒素中的一个重要的组包括孔形成毒素，例如溶血素和杀白细胞素，以及小肽毒素，其对红细胞和白细胞具有溶解活性，特别是对代表抗链球菌的主要防线的嗜中性粒细胞具有溶解活性。金黄色。这些毒素导致组织损伤，促进细菌在远处器官中的传播和生长，并使病原体能够逃避宿主的先天免疫反应。此外，已知荚膜多糖（CP）保护细菌免受多形核白细胞的吞噬活性，并且已被验证为重要的疫苗靶标。综合生物治疗学公司正在研制以毒素为基础的疫苗，并与CP联合使用，以对抗沙门氏菌.金黄色葡萄球菌感染造孔？溶血素（Hla），也称为？毒素（AT）几乎由所有菌株产生，并与几种S.金黄色葡萄球菌侵袭性疾病最近的微生物学和血清学研究，在人类与S。金黄色葡萄球菌菌血症也显示了毒素和酚可溶性调节蛋白（PSM）对金黄色葡萄球菌的重要性。金黄色葡萄球菌致病性。根据我们最近的研究，预先存在的抗体对Hla，毒素和PSM？3显著降低成年S.金黄色葡萄球菌菌血症该I期SBIR的目的是评估基于葡萄球菌毒素的新型糖缀合物疫苗的可行性。候选疫苗的设计代表了一个关键的结构域在N末端的Hla（AT 62）融合到毒素和PSM？3.我们以前已经证明，AT 62疫苗提供了对菌血症和肺炎的保护。该提案利用Glycovaxyn Inc.开发的独特且新颖的体内生物缀合技术。将该杂合类毒素与5型荚膜多糖（CP 5）缀合，作为生物缀合物功效的概念证明。生物接合技术涉及E.大肠杆菌细胞工程化以表达弯曲杆菌酶PglB以及S.金黄色葡萄球菌CP 8生物合成。PglB将N-连接的CP 8链转移到引入这些细胞的疫苗构建体中。这种新技术是糖缀合物疫苗领域的一个重大发展，与传统的化学缀合物相比具有多个优点。在特异性目标1中，将产生三种毒素的融合物，并鉴定减毒突变并将其掺入融合构建体中。将检测候选疫苗的免疫原性，然后在目标2中生成生物缀合物。在目标3中，将在代表菌血症/脓毒症和皮肤和软组织感染的两种主要疾病模型中评价候选疫苗的保护效力。在成功完成这项拟议的研究后，我们设想了一个II期SBIR，其中将为其他主要的S。金黄色葡萄球菌荚膜多糖CP 8和多价疫苗（包括我们组目前正在开发的其他类毒素疫苗的组合）的功效进行了广泛的测试。最终目标是与大型制药公司建立战略合作伙伴关系，将候选疫苗转入临床开发。

DESCRIPTION (provided by applicant): Staphylococcus aureus is a Gram-positive human pathogen that causes a wide range of infections from skin and soft tissue infections (SSTI) to life threatening sepsis and pneumonia. The pathogenicity of S. aureus is dependent on numerous virulence factors, including cell surface proteins and polysaccharides, as well as secreted toxins. An important group of these toxins includes pore forming toxins such as hemolysins and leukocidins, as well as small peptidic toxins, with lytic activity towards erythrocytes and leukocytes particularly the neutrophils that represent the major line of defense against S. aureus. These toxins cause tissue damage, promote bacterial dissemination and growth in distant organs, and enable the pathogen to evade the host innate immune response. Furthermore, capsular polysaccharide (CP) are known to protect bacteria from phagocytic activity of polymorphonuclear leukocytes and have been validated as important vaccine targets. Integrated BioTherapeutics (IBT) is pursuing development of toxin- based vaccines in combination with CPs against S. aureus infections. The pore-forming ?-hemolysin (Hla), also known as ?-toxin (AT), is produced by nearly all strains and is implicated in several S. aureus invasive diseases. Recent microbiological and serological studies in humans with S. aureus bacteremia also show the importance of ¿-toxin and phenol-soluble modulins (PSM) for S. aureus pathogenicity. Based on our recent study, pre-existing antibodies against Hla, ¿-toxin and PSM?3 significantly reduce the risk of sepsis in adults with S. aureus bacteremia. The goal of this Phase I SBIR is to evaluate the feasibility of a novel glycoconjugate staphylococcal toxin based vaccine. Vaccine candidates have been designed that represent a critical structural domain at the N terminus of Hla (AT62) fused to ¿-toxin and PSM?3. We have shown previously that AT62 vaccine provides protection against bacteremia and pneumonia. This proposal utilizes a unique and novel in vivo bioconjugation technology developed by Glycovaxyn Inc. to conjugate this hybrid toxoid with capsular polysaccharide Type 5 (CP5) as proof of concept of the efficacy of the bioconjugate. The bioconjugation technology involves E. coli cells engineered to express the Campylobacter enzyme PglB as well as the genes required for S. aureus CP8 biosynthesis. PglB transfers N-linked CP8 chains to the vaccine construct introduced into these cells. This novel technology is a major development in glycoconjugate vaccine field with multiple advantages over the conventional chemical conjugation. In the Specific Aim 1 fusions of the three toxins will be generated and attenuating mutations identified and incorporated into the fusion construct. The candidate vaccine will be tested for immunogenicity and then bioconjugates generated in Aim 2. In Aim 3 the protective efficacy of the vaccine candidate will be evaluated in two major disease models representing bacteremia/sepsis and skin and soft tissue infections. Upon successful completion of this proposed research we envision a Phase II SBIR in which similar bioconjugate will be produced for the other major S. aureus capsular polysaccharide CP8 and the efficacy of the multivalent vaccine (including combination other toxoid vaccines currently under development in our group) extensively tested. The ultimate goal is to build a strategic partnership with large pharma to transition the vaccine candidate into clinical development.