Abstract：
Meningococcal glycoconjugate vaccines sourced from capsular polysaccharides (CPSs) of pathogenic Neisseria meningitidis strains are well-established measures to prevent meningococcal disease. However, the exact structural factors responsible for antibody recognition are not known. CPSs of Neisseria meningitidis serogroups Y and W differ by a single stereochemical center, yet they evoke specific immune responses. Herein, we developed specific monoclonal antibodies (mAbs) targeting serogroups C, Y, and W and evaluated their ability to kill bacteria. We then used these mAbs to dissect structural elements responsible for carbohydrate-protein interactions. First, Men oligosaccharides were screened against the mAbs using ELISA to select putative lengths representing the minimal antigenic determinant. Next, molecular interaction features between the mAbs and serogroup-specific sugar fragments were elucidated using STD-NMR. Moreover, X-ray diffraction data with the anti-MenW CPS mAb enabled the elucidation of the sugar-antibody binding mode. Our findings revealed common traits in the epitopes of all three sialylated serogroups. The minimal binding epitopes typically comprise five to six repeating units. Moreover, the O-acetylation of the neuraminic acid moieties was fundamental for mAb binding. These insights hold promise for the rational design of optimized meningococcal oligosaccharides, opening new avenues for novel production methods, including chemical or enzymatic approaches.
摘要：
源自致病性脑膜炎奈瑟菌菌株的荚膜多糖(CPS)的脑膜炎球菌糖缀合物疫苗是预防脑膜炎球菌疾病的既定措施。然而,负责抗体识别的确切结构因素尚不清楚。脑膜炎奈瑟氏球菌血清群Y和W的CPS差异在于一个立体化学中心，然而它们引起特定的免疫反应。在这里，我们开发了特异性单克隆抗体（mAb）靶向血清群C，Y,和W并评估了它们杀死细菌的能力。然后，我们使用这些mAb来解剖负责碳水化合物-蛋白质相互作用的结构元件。首先,使用ELISA针对mAb筛选人寡糖以选择代表最小抗原决定簇的推定长度。接下来,使用STD-NMR阐明了mAb和血清群特异性糖片段之间的分子相互作用特征。此外，使用抗MenWCPSmAb的X射线衍射数据能够阐明糖-抗体结合模式。我们的发现揭示了所有三个唾液酸化血清群的表位中的共同特征。最小结合表位通常包含五至六个重复单元。此外，神经氨酸部分的O-乙酰化是mAb结合的基础。这些见解为优化脑膜炎球菌寡糖的合理设计提供了希望，为新颖的生产方法开辟了新的途径，包括化学或酶方法。
