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

描述（由申请人提供）：金黄色葡萄球菌是一种人类病原体，可引起广泛的疾病，从皮肤和软组织感染（SSTI）到危及生命的败血症和肺炎。过去二十年来，医院和社区的金黄色葡萄球菌感染呈上升趋势，对甲氧西林（MRSA）和最后的抗生素万古霉素（VISA和VRSA）耐药的金黄色葡萄球菌菌株迅速传播，对全球公共卫生构成重大威胁。目前还没有疫苗或免疫疗法可用于预防或治疗金黄色葡萄球菌感染。金黄色葡萄球菌的致病性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，这些毒素引起组织损伤，促进细菌在远处器官的传播和转移生长，并使病原体逃避宿主的先天免疫反应。针对个别毒力因子的几种疫苗或候选治疗方法已经进行了测试，但收效甚微，这突出表明需要采取多方面的方法。这是一项基于Integrated BioTherapeutics （IBT）开发的金黄色葡萄球菌抗体和Zyngenia公司开发的多特异性抗体（Zybodies(tm)）生成新技术的合作提案。Zybody包括一种传统的单克隆抗体（mAb），其肽（分子识别域，MRDs）基因融合到抗体重链和轻链的N和/或c端。由此产生的Zybody二价结合亲本单抗的靶标，并通过合并的mrd结合多达4个额外的靶标。该I期SBIR的目标是利用Zybody技术同时靶向表面多糖和分泌毒素，从而在感染部位隔离毒素，防止细菌传播和毒血症，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Aim 1中，将构建三特异性合体，每个合体将针对一种细胞相关毒力因子（8型胶囊多糖或壁壁壁磷壁酸）以及两种可溶性毒素（α溶血素和潘通-瓦伦丁杀白细胞素）。三特异性合体将在体外产生并进行功能表征，因为它们具有结合和中和毒素并增强金黄色葡萄球菌调理吞噬的能力。在Aim 2中，三特异性合体将在几种动物模型中进行测试，包括菌血症、肺炎和皮肤感染模型。候选药物的疗效将以生存、细菌负荷和毒血症为终点来确定。该I期SBIR为未来开发用于人类的有效多特异性临床前候选药物提供了概念证明。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提交新药研究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. PUBLIC HEALTH RELEVANCE: Staphylococcus aureus is a bacteria that causes a wide range of infections ranging from skin and soft tissue infections to life threatening diseases like sepsis and pneumonia. S. aureus is becoming increasingly resistant to antibiotics. In this proposal we seek to develop a novel therapeutic that combines strategies for attacking multiple virulence factors of S. aureus into a single molecule. If successful this project can lead to an effective therapy for community and hospital acquired staphylococcal infections.