A novel Structure Based Vaccine for staphylococcal alpha hemolysin

描述（由申请人提供）：金黄色葡萄球菌是一种革兰氏阳性人类病原体，可引起广泛的感染，从皮肤和软组织感染到危及生命的疾病，如败血症和肺炎。S.金黄色葡萄球菌因其获得和进化对抗微生物剂的抗性机制的能力而众所周知，同时存在对可用于临床实践的所有抗生素的抗性，这强调了对抗这些病原体的新方法的巨大需求。目前还没有疫苗或治疗剂可用于预防或治疗由S.金黄色。S.金黄色葡萄球菌是医院获得性感染的最普遍原因，近年来其在社区中的传播速度也上升到令人震惊的水平。肺炎是肺炎链球菌最严重和最突出的并发症之一。金黄色葡萄球菌感染导致仅在美国每年就有50，000例。S.金黄色葡萄球菌肺炎传统上与呼吸机相关，但近年来它也被认为是社区获得性肺炎的主要原因，主要发生在健康的儿童和年轻人中。S.金黄色葡萄球菌产生广泛的具有免疫逃避和免疫调节功能的分泌毒素。在这些毒素中，α-溶血素是已知的最有效的毒素之一，包括我们在内的多个研究小组的研究表明，α-溶血素（Hla）也称为α毒素（AT）似乎是S.当在反映人类疾病的动物模型中测试时，金黄色葡萄球菌肺炎和皮肤感染。由于其毒性作用，野生型Hla不能用作疫苗。该I期SBIR的主要目标是完成基于晶体结构设计的新型Hla疫苗的概念验证研究。已经设计了两种疫苗候选物，其代表参与寡聚化的Hla的N末端处的结构域：i）AT的N末端62个氨基酸（AT-62 aa）和ii）包括氨基酸1-62和223-236的延伸构建体，表示为AT-79 aa。该提案中提供的初步数据表明AT-62 aa在S.金黄色葡萄球菌感染，而先前描述的AT-50 aa（其破坏结构域结构）仅提供轻微的寿命延长，但当与铝胶佐剂一起使用时没有保护性（与使用IFA的先前报道相反）。该提议概述于三个具体目标中：在目标1中，我们将基于His标记的AT-62 aa蛋白的免疫原性研究，使用三种不同的佐剂（在许可产品（明矾）中或在人用临床试验中（CpG和IDC-1001））来鉴定最佳疫苗候选物，并鉴定最佳佐剂。在具体目标2中，我们将开发用于目标1中选择的疫苗构建体的无标签蛋白的生产和纯化的初步程序。我们还将通过生物物理方法表征蛋白质，并进行桥接研究以确认其体内免疫原性。在具体目标3中，我们将进行一整套概念验证研究，以显示最佳候选疫苗在四种不同感染小鼠模型中的保护效力：肺炎、代表SSTI的皮下脓肿模型、菌血症/脓毒症和手术伤口感染。这项建议是IBT和布里格姆妇女医院的Jean Lee博士实验室之间的合作努力。在第一阶段完成后，我们设想了第二阶段SBIR，重点是完成临床前开发，从而向美国食品药品监督管理局提交研究性新药（IND）申请。 公共卫生相关性：金黄色葡萄球菌是一种细菌，可引起广泛的感染，从皮肤和软组织感染到危及生命的疾病，如败血症 和肺炎。肺炎是肺炎链球菌最严重和最突出的并发症之一。金黄色葡萄球菌感染导致仅在美国每年就有50，000例。S.金黄色葡萄球菌对抗生素的耐药性越来越强。在这项提议中，我们试图开发一种针对α溶血素的疫苗，α溶血素是由链球菌产生的最强毒素之一。金黄色。这种毒素与肺炎和皮肤感染密切相关。针对α溶血素的疫苗有望保护人类免受葡萄球菌感染的危及生命的并发症。

DESCRIPTION (provided by applicant): Staphylococcus aureus is a gram positive human pathogen 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 well known for its ability to acquire and evolve resistance mechanisms towards antimicrobial agents and meanwhile there are resistances towards all antibiotics available for clinical practice emphasizing a great need fo novel approaches to combat these pathogens. Currently there are no vaccines or therapeutics available for prevention or treatment of diseases caused by S. aureus. S. aureus is the most prevalent cause of hospital acquired infections and in recent years its rate of spread through the community has also been rising to an alarming level. Pneumonia is one of the most severe and prominent complications of S. aureus infection leading with 50,000 cases per year in the US alone. S. aureus pneumonia has been traditionally ventilator associated but in recent years it has been recognized also as a major cause of community acquired pneumonia primarily in otherwise healthy children and young individuals. S. aureus produces a wide range of secreted toxins with immune evasion and immune modulatory functions. Among these alpha hemolysin is known to be one of the most potent toxins and studies from multiple groups including ours show that alpha- hemolysin (Hla) also known as alpha toxin (AT) seems to be a a key virulence factor for S. aureus pneumonia and skin infection when tested in animal models reflecting human diseases. Hla cannot be used as a vaccine in its wild type form due to its toxic effect. The main goal of this Phase I SBIR is to complete proof of concept studies on a novel Hla vaccine designed based on crystallographic structure. Two vaccine candidates have been designed that represent a structural domain at the N terminus of Hla involved in oligomerization: i) the N-terminal 62 amino acids of AT (AT-62aa) and ii) an extended construct including amino acids 1-62 and 223-236 denoted as AT-79aa. Preliminary data presented in this proposal indicate induction of neutralizing antibodies and protective efficacy of AT-62aa in a pneumonia model of S. aureus infection, while a previously described AT-50aa (which disrupts the domain structure) only afforded a slight extension of life but was not protective when used with Alhydrogel adjuvant (in contrast to previous reports using IFA). This proposal is outlined in three specific Aims: In Aim 1, we will identify the best vaccine candidate based on immunogenicity studies of His-tagged AT-62aa protein using three different adjuvants that are either in licensed products (alum) or in clinical trial for human use (CpG and IDC-1001) and identify the optimal adjuvant. In specific Aim 2, we will develop a preliminary procedure for production and purification of a tag-free protein for the vaccine construct selected in Aim 1. We will also characterize the protein by biophysical methods, and perform a bridging study to confirm its immunogenicity in vivo. In specific Aim 3, we will perform a full set of proof of concept studies to show the protective efficacy of the optimal vaccine candidate in four different mouse models of infection: pneumonia, subcutaneous abscess model representing SSTI, bacteremia/sepsis, and surgical wound infection. This proposal is a collaborative effort between IBT and Dr. Jean Lee's laboratory at Brigham Women Hospital. Upon completion of the Phase I we envision a Phase II SBIR focused on completing preclinical development leading to submission of an Investigational New Drug (IND) application to the Food and Drug Administration. 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. Pneumonia is one of the most severe and prominent complications of S. aureus infection leading with 50,000 cases per year in the US alone. S. aureus is becoming increasingly resistant to antibiotics. In this proposal we seek to develop a vaccine for alpha hemolysin, one of the most potent toxins produced by S. aureus. This toxin is critically involved in pneumonia and skin infections. A vaccine against alpha hemolysin is expected to protect humans from life threatening complications of staphylococcal infections.