Single Antigen Strategy for Prevention of Recurrent and Chronic Suppurative Otitis

 描述(由申请人提供)：这项建议的目标是评估针对保守的细菌表面多糖聚N-乙酰氨基葡萄糖(PNAG)的抗体预防复发性和慢性化脓性中耳炎(CSOM)的潜力，该CSOM是由中耳炎(OM)的两种最常见的病原体-肺炎链球菌(SP)和非分型流感嗜血杆菌(NTHi)引起的。这两种微生物都会产生表面PNAG，这是一种被认为是几种细菌生物膜所必需的分子。Pier博士和Pelton博士及其合作者已经发表了证据表明，PNAG作为一种胶囊样抗原表达，嵌入已知的SP和NTHi胶囊中，在儿童和龙猫中直接从中耳获得的分离株上。这项建议的独特之处将是针对两种病原体上的一种抗原，这种抗原可能会影响与复发性OM相关的生活质量降低，以及与CSOM相关的深度耳聋和化脓性并发症。由于PNAG是由许多共生生物(大肠杆菌、表皮葡萄球菌、脆弱芽孢杆菌)产生的，因此PNAG的天然抗体在人类中很常见。然而，天然抗体与高度乙酰化的PNAG糖体结合(60%乙酰化)，对调理细菌或杀菌的效率较低，对感染几乎没有保护作用。Pier和他的同事们报告说，通过将乙酰化水平降低到30%，PNAG产生的糖型被称为脱乙酰化PNAG(DPNAG)，当连接到针对SP和NTHi的载体蛋白时，可以诱导调理和/或杀菌抗体。重要的是，这些抗体似乎对正常菌群没有影响，人类单抗到PNAG的第一阶段临床试验结果以及包括长期动物研究在内的多条其他证据线证明了这一点。该项目将评估 在已建立的细菌性中耳炎的灰鼠模型中，被动转移PNAG的多克隆和单抗对肺炎球菌和非分型流感嗜血杆菌中耳疾病的体内保护作用，为未来的PNAG结合疫苗效力的研究确定抗PNAG抗体的保护性抗体浓度，并评估9GlcNH2-TT结合疫苗的免疫原性，以展示被动-主动策略在减轻儿童中耳疾病负担方面的潜力。

 DESCRIPTION (provided by applicant): The goal of this proposal is to evaluate the prophylactic potential of antibodies to the conserved bacterial surface polysaccharide poly-N-acetyl glucosamine (PNAG) for prevention of recurrent and chronic suppurative otitis media (CSOM) specifically caused by the two most common pathogens of otitis media (OM), Streptococcus pneumoniae (SP) and non-typeable Haemophilus influenzae (NTHi). Both of these organisms produce surface PNAG, a molecule recognized to be essential for several bacterial biofilms. Drs. Pier and Pelton and collaborators have already published evidence that PNAG is expressed as a capsule-like antigen, intercalated within the known capsules of SP and NTHi on isolates obtained directly from the middle ear in children and in chinchillas. The unique aspect of this proposal will be targeting one antigen, present on both pathogens that could impact the reduced quality of life associated with recurrent OM and the profound deafness and suppurative complications associated with CSOM. As PNAG is produced by many commensal organisms (E. coli, S. epidermidis, B. fragilis), natural antibody to PNAG is commonly found in humans5. However, natural antibodies bind to the highly acetylated glycoform of PNAG (>60% acetylation) and are of low efficiency for mediating opsonic or bactericidal killing and show littl protective efficacy against infection5. Pier and colleagues have reported that by reducing the levels of acetylation to <30%, the glycoform of PNAG produced, called deacetylated PNAG (dPNAG), induces opsonic and/or bactericidal antibodies when conjugated to carrier proteins against both SP and NTHi. Importantly, these antibodies appear to have no effect on normal flora as evidenced by results from a phase 1 clinical trial of a MAb to PNAG in humans and multiple other lines of evidence including long-term animal studies. This project will evaluate the in vivo efficacy of passively transferred polyclonal and monoclonal antibody to PNAG for protection against pneumococcal and nontypable haemophilus influenzae middle ear disease in a well-established chinchilla model of bacterial otitis media, define a protective antibody concentration of anti- PNAG antibody for future studies of PNAG-conjugate vaccine efficacy, and evaluate immunogenicity of a 9GlcNH2-TT conjugate vaccine to demonstrate the potential of a passive-active strategy for reducing the burden of middle ear disease in children.