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

这项研究计划的长期目标是了解细菌的免疫化学特性， 聚-N-乙酰葡糖胺（PNAG），并利用这一信息生产有效的疫苗， 将PNAG表达为表面多糖的革兰氏阳性和革兰氏阴性细菌病原体。 PNAG由许多临床分离的S. epidermidis和几乎所有的S.金黄色，两个 最常见的院内细菌感染的原因，以及致病性大肠杆菌。大肠杆菌、耶尔森氏菌属（Yersinia spp.） 包括鼠疫耶尔森氏菌、博德特氏菌属（Bordetella spp.）和放线杆菌属（Actinobacillus spp.）所有这些微生物都是导致 人类和动物疾病。产生了最佳的调理素杀伤和保护性免疫 当正常高度乙酰化的PNAG分子（天然PNAG，> 70%N-乙酰化）被脱乙酰化时 （dPNAG），使得<20%的氨基被乙酰化。在本提案中，将这些调查结果扩展到 致病性大肠大肠杆菌和耶尔森氏菌。将采取主动和被动疫苗接种， PNAG和dPNAG，以确定该抗原作为基础广泛的抗菌疫苗的效力。抗体 通过结合测定（ELISA）、补体沉积ELISA、调理素杀伤测定， 和受感染动物的体内保护。进一步的目的是使用合成的（3-1-6连接的葡糖胺 寡聚体以限定结合最大保护性抗体的表位的化学结构， 评价寡糖-蛋白诱导的抗体的结合、调理和保护功效 结合疫苗。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，这些单抗的活性将使用核糖体或 噬菌体展示技术以在体外使抗体亲和力成熟。从公共卫生的角度来看，积极或 被动接种疫苗是控制传染病的最有效策略， 表面蛋白缀合的多糖抗原在降低感染率方面非常有效， 几种细菌病原体由于PNAG是由多种不同的细菌病原体产生的， 有效的PNAG疫苗可以显著减少社区获得性和 金黄色葡萄球菌引起的医院内感染，E.大肠杆菌、耶尔森氏菌属（Yersinia spp.）包括瘟疫的起因， 可能是其他产生PNAG的生物。

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 (3-1-6 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.