Development of a Panton Valentine Leukocidin bivalent vaccine

描述（由申请人提供）：金黄色葡萄球菌是一种可怕的人类病原体，在医院和社区中引起严重感染。金黄色葡萄球菌产生多种毒力因子，包括一系列具有免疫抑制、免疫调节和细胞毒性活性的外毒素。其中一种毒素，Panton Valentine Leukocidin (PVL)，是一种与社区获得性金黄色葡萄球菌感染的严重肺炎病例相关的孔形成毒素。目前针对PVL的疫苗工作主要集中在单一野生型亚基上。然而，这种方法可能会对人类使用造成严重的安全问题。本研究计划的总体目标是开发一种针对PVL的重组、突变（减毒）和二价疫苗。该建议是基于PVL成分的广泛结构分析和基于结构的合理设计潜在的减毒突变体。第一阶段SBIR设计有两个具体目标。在Aim 1中，我们将在PVL的LukS和LukF亚基编码基因中引入点突变，以消除毒素寡聚化和由此产生的孔形成，并在体外表征突变PVL亚基的完整性和活性。候选疫苗的衰减程度将在体外和体内测定。在Aim 2中，我们试图进一步表征和筛选PVL突变亚基作为候选疫苗，基于使用天然PVL毒素的小鼠攻击模型的有效性研究，并使用MRSA克隆USA300对BALB/c小鼠的金黄色葡萄球菌感染进行初步评估。I期的终点是确定一个或两个临床前候选药物。在SBIR的II期，我们将完成所选候选疫苗的临床前疗效、配方和安全性研究。最终目标是开发一种安全有效的PVL抗原，可以整合到包括其他毒素或细胞相关金黄色葡萄球菌抗原的多价金黄色葡萄球菌疫苗制剂中。

DESCRIPTION (provided by applicant): Staphylococcus aureus (S.aureus) is a formidable human pathogen responsible for severe infections in the hospitals and community. S. aureus produces a variety of virulence factors including a range of exotoxins with immune inhibitory, immunomodulatory, and cytotoxic activities. One of these toxins, the Panton Valentine Leukocidin (PVL), is a pore forming toxin associated with severe pneumonia cases of community acquired S. aureus infections. Current vaccine efforts targeting PVL are focused on single wild type subunits. However, this approach may pose serious safety concerns for human use. The overall goal of this research plan is to develop a recombinant, mutant (attenuated) and bivalent vaccine against PVL. The proposal is based on extensive structural analysis of the components of PVL and structure- based, rational design of potentially attenuated mutants. This Phase I SBIR is designed in two Specific Aims. In Aim 1 we will introduce point mutations into the genes encoding for the LukS and LukF subunits of PVL to abolish toxin oligomerization and the resulting pore formation, and characterize the integrity and activity of the mutant PVL subunits in vitro. The degree of attenuation of the vaccine candidates will be determined in vitro and in vivo. In Aim 2 we seek to further characterize and down-select mutant PVL subunits as vaccine candidate(s) based on efficacy studies using mouse challenge models of native PVL toxin and to perform preliminary evaluation in S. aureus infections in BALB/c mice using the MRSA clone USA300. The endpoint for the Phase I is the identification of one or two preclinical candidates. In Phase II of this SBIR we will complete the preclinical efficacy, formulation, and safety studies for the selected vaccine candidate(s). The ultimate goal is to develop a safe and effective PVL antigen that could be integrated into a multivalent S. aureus vaccine formulation that will include other toxins or cell- associated S. aureus antigens. PUBLIC HEALTH RELEVANCE: This proposal is aimed at development of a safe and effective vaccine for one the toxins produced by Staphylococcus aureus (SA), known as PVL. Antibiotic resistant SA infections have been on the rise in the past two decades both in the hospitals and in the community. There are currently no vaccine available against SA infections. PVL is known to play an important role in severe cases of pneumonia caused by community acquired MRSA. The vaccine produced under this program is expected to be a component of a multicomponent vaccine for prevention of SA infections.