Multi-specific Antibody Therapy by targeting S. aureus toxins and polysaccharides

描述（由申请方提供）：金黄色葡萄球菌是一种人类病原体，可引起从皮肤和软组织感染（SSTI）到危及生命的败血症和肺炎等多种疾病。感染S。金黄色葡萄球菌在医院和社区的感染在过去的二十年中呈上升趋势，耐甲氧西林（MRSA）和最后手段抗生素万古霉素（VISA和VRSA）的金黄色葡萄球菌菌株对全球公共卫生构成重大威胁。目前没有疫苗或免疫治疗可用于预防或治疗S。金黄色葡萄球菌感染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，以及引起组织损伤、促进细菌传播和远处器官中的转移生长并使病原体能够逃避宿主先天免疫应答的分泌毒素。针对单个毒力因子的几种疫苗或治疗候选物已经过测试，但几乎没有成功，这突出了对多方面方法的需要。这是一个基于S.在Integrated BioTherapeutics（IBT）开发的金黄色葡萄球菌抗体和由Zyngenia，Inc.开发的用于产生多特异性抗体的新技术（Zybodies（TM））。Zybody包含常规单克隆抗体（mAb），肽（分子识别结构域，MRD）与抗体重链和轻链的N-和/或C-末端遗传融合。所得的Zybody双链抗体结合亲本mAb的靶标，并通过掺入的MRD装备以结合多达4个额外的靶标。该I期SBIR的目标是采用Zybody技术同时靶向表面多糖和分泌的毒素，从而能够在感染部位隔离毒素，预防细菌传播和毒血症，并通过中性粒细胞有效清除细菌和毒素。该提案有两个具体目标。在目标1中，将构建三特异性Zybody，其每一个将靶向一种细胞相关毒力因子（8型荚膜多糖或壁磷壁酸）以及两种可溶性毒素（α溶血素和Panton-Valentine杀白细胞素）沿着。将产生三特异性Zybody，并在体外功能上表征其结合和中和毒素并增强金黄色葡萄球菌调理吞噬作用的能力。在目的2中，将在几种动物模型中测试三特异性zybody，包括菌血症、肺炎和皮肤感染模型。将使用生存期、细菌负荷和毒血症作为终点来确定候选药物的疗效。这一I期SBIR可作为未来开发人用有效多特异性临床前候选药物的概念验证。在随后的II期，我们设想Zybodies的人源化，MRD序列的优化，分子靶点的扩展，以及向FDA提交研究性新药申请所需的标准临床前研究。

DESCRIPTION (provided by applicant): Staphylococcus aureus is a human pathogen that causes a wide range of diseases from skin and soft tissue infections (SSTI) to life threatening sepsis and pneumonia. Infections with S. aureus in the hospitals and community have been on the rise over the past two decades and the rapid spread of S. aureus strains resistant to methicilin (MRSA) and the last resort antibiotic vancomycin (VISA and VRSA) is posing a major threat to global public health. There are currently no vaccines or immunotherapeutics available for prophylaxis or treatment of S. aureus infections. The pathogenicity of S. aureus is dependent on many virulence factors, including cell surface proteins and polysaccharides, as well as secreted toxins that cause tissue damage, promote bacterial dissemination and metastatic growth in distant organs, and enable the pathogen to evade the host innate immune response. Several vaccine or therapeutic candidates that target individual virulence factors have been tested with little success, highlighting the need for a multi-faceted approach. This is a collaborative proposal relying on S. aureus antibodies developed at Integrated BioTherapeutics (IBT) and a novel technology for generation of multispecific antibodies (Zybodies(tm)) developed by Zyngenia, Inc. A Zybody comprises a conventional monoclonal antibody (mAb) to which peptides (Molecular Recognition Domains, MRDs) are genetically fused to the N- and/or C-termini of the antibody's heavy and light chains. The resulting Zybody bivalently binds the target of the parental mAb and is armed to bind up to 4 additional targets through the incorporated MRDs. The goal of this Phase I SBIR is to employ the Zybody technology for simultaneous targeting of surface polysaccharides and secreted toxins enabling the sequestration of toxins at site of infection, prevention of bacterial dissemination and toxemia, and efficient clearance of th bacteria and toxins by neutrophils. The proposal has two Specific Aims. In Aim 1, Tri-specific Zybodies will be constructed each of which will target one cell-associated virulence factor (capsule polysaccharide Type 8 or wall teichoic acid) along with two soluble toxins (alpha hemolysin and Panton-Valentine leukocidin). Tri-specific Zybodies will be produced and functionally characterized in vitro for their ability to bind and neutralize toxin(s) and enhance S aureus opsonophagocytosis. In Aim 2 the tri-specific zybodies will be tested in several animal models including bacteremia, pneumonia and skin infection models. Efficacy of the candidates will be determined using survival, bacterial burden, and toxemia as endpoints. This Phase I SBIR serves as proof of concept for future development of effective multispecific preclinical candidates for human use. In a subsequent Phase II we envision humanization of the Zybodies, optimization of the MRD sequences, expansion of molecular targets, as well as standard preclinical studies required for submission of an Investigational New Drug Application to FDA.