Poly-N-acetyl glucosamine as a vaccine for bacterial pathogens

描述（由申请方提供）：本研究项目的长期目标是了解细菌聚-N-乙酰葡糖胺（PNAG）的免疫化学特性，并利用该信息生产针对多种革兰氏阳性和革兰氏阴性细菌病原体（将PNAG表达为表面多糖）的有效疫苗。PNAG由许多临床分离的S. epidermidis和几乎所有的S.金黄色葡萄球菌，医院感染的两个最常见的原因，以及致病性大肠杆菌。大肠杆菌、耶尔森氏菌属（Yersinia spp.）包括Y.鼠疫杆菌、博德特氏菌属（Bordetella spp.）和放线杆菌属（Actinobacillus spp.）所有这些生物都是人类和动物疾病的重要原因。当通常高度乙酰化的PNAG分子（天然PNAG，> 70%N-乙酰化）被脱乙酰化（dPNAG）使得<20%的氨基被乙酰化时，产生对葡萄球菌的最佳调理素杀伤和保护性免疫。在此建议中，这些发现的致病性E。大肠杆菌和耶尔森氏菌。将进行，使用针对天然PNAG和dPNAG的主动和被动疫苗接种，以确定该抗原作为广泛基础的抗菌疫苗的功效。将通过结合测定（ELISA）、补体沉积ELISA、调理素杀伤测定和感染动物的体内保护来评价抗体活性。进一步的目标是使用合成的？1-6连接的葡糖胺寡聚物的表位，以确定结合最大保护性抗体的表位的化学结构，并评估由寡糖-蛋白质缀合物疫苗引发的抗体的结合、调理和保护功效。将研究针对天然PNAG和dPNAG的全人单克隆抗体作为被动预防剂的潜力，并且将使用核糖体或噬菌体展示技术来增强这些Mab的活性以使抗体在体外亲和力成熟。从公共卫生的角度来看，主动或被动接种疫苗是控制传染病的最有效策略，含有表面蛋白缀合的多糖抗原的疫苗在降低几种细菌病原体的感染率方面非常有效。由于PNAG是由多种不同的细菌病原体产生的，因此有效的PNAG疫苗可以显著降低由葡萄球菌、大肠杆菌和葡萄球菌引起的社区获得性疾病和医院获得性疾病的负担。大肠杆菌、耶尔森氏菌属（Yersinia spp.）包括鼠疫的原因，可能还有其他产生PNAG的生物。

DESCRIPTION (provided by applicant): The long-term goal of this research program is to understand the immunochemical properties of bacterial poly-N-acetyl glucosamine (PNAG) and utilize this information to produce an effective vaccine for multiple Gram-positive and Gram-negative bacterial pathogens that express PNAG as a surface polysaccharide. PNAG is produced by many clinical isolates of S. epidermidis and almost all strains of S. aureus, the two most common causes of nosocomial bacterial infection, as well as by pathogenic E. coli, Yersinia spp. including Y. pestis, Bordetella spp. and Actinobacillus spp. All of these organisms are significant causes of human and animal disease. Optimal opsonic-killing and protective immunity to Staphylococci is engendered when the normally highly acetylated PNAG molecule (native PNAG, >70% N-acetylated) is deacetylated (dPNAG) such that <20% of the amino groups are acetylated. In this proposal, extension of these findings to pathogenic E. coli and Yersinia spp. will be undertaken, using active and passive vaccination against native PNAG and dPNAG to determine the efficacy of this antigen as a broad-based antibacterial vaccine. Antibody activity will be evaluated by binding assays (ELISA), complement deposition ELISA, opsonic-killing assays, and in vivo protection of infected animals. Further aims are to use synthetic ?-1-6 linked glucosamine oligomers to define the chemical structure of the epitopes that bind to maximally protective antibody and evaluate the binding, opsonic and protective efficacy of antibodies elicited by oligosaccharide-protein conjugate vaccines. Fully human monoclonal antibodies to native PNAG and dPNAG will be investigated for potential as passive prophylactic agents and the activity of these Mabs will be enhanced using ribosome or phage display technology to affinity mature the antibodies in vitro. From a public health viewpoint, active or passive vaccination is the most effective strategy to control infectious diseases, and vaccines containing surface protein-conjugated polysaccharide antigens have been highly effective at reducing infection rates by several bacterial pathogens. Since PNAG is produced by multiple and diverse bacterial pathogens, an effective PNAG vaccine could lead to a significant reduction in the burden of both community acquired and nosocomial disease caused by Staphylococci, E. coli, Yersinia spp. including the cause of plague, and possibly other PNAG-producing organisms.