Synthesis of glycoconjugate vaccines for Candida albicans using novel linker methodology.
Synthesis of glycoconjugate vaccines for Candida albicans using novel linker methodology.
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DOI：
10.1021/jo051065t
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发表时间：
2005-07
期刊：
影响因子：
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通讯作者：
Xiangyang Wu;D. Bundle
中科院分区：
文献类型：
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作者：
Xiangyang Wu;D. Bundle
[反应：假丝酵母属的细胞壁磷酸甘露聚糖是一种复杂的N-连接糖蛋白，其聚糖链主要含有α-连接甘露糖残基。然而，临床上重要的念珠菌属菌株的磷酸甘露聚糖的次要β-甘露聚糖组分在真菌疾病的动物模型中提供免疫保护，因此有望作为缀合物疫苗的组分。这种重要的抗原以不同的形式存在，通过磷酸二酯键（酸不稳定的β-甘露聚糖）或直接通过糖苷键与α-甘露聚糖主链连接。为了可重复地合成和评价缀合物疫苗，需要用于合成不同寡糖表位的稳健方法。在这里，我们报告了两种类型的表位的克级合成的方法，利用葡萄糖基三氯乙酰亚胺供体2，首先创建一个β-吡喃葡萄糖苷键，然后通过氧化还原序列差向异构化的C-2中心，提供了一个有效的多克级途径的β-甘露吡喃糖苷5，8和15。糖苷16-18与同双官能己二酸对硝基苯基二酯在无水DMF中的反应以良好的产率得到相应的半酯，并且具有足够的稳定性以允许色谱纯化。随后在温和的缀合条件下与BSA和破伤风菌素（TT）缀合，以良好的效率得到相应的三糖和四糖新糖蛋白。缀合方法也适用于少量（mg）较大寡糖与不同蛋白质的偶联。
[reaction: see text] The cell wall phosphomannan of Candida species is a complex N-linked glycoprotein with a glycan chain that contains predominantly alpha-linked mannose residues. However, it is the minor beta-mannan component of the phosphomannan of clinically important Candida strains that provides immunological protection in animal models of fungal disease and hence holds promise as a component of conjugate vaccines. This important antigen occurs in different forms linked to the alpha-mannan backbone via a phosphodiester bond (acid-labile beta-mannan) or directly via a glycosidic bond. To reproducibly synthesize and evaluate conjugate vaccines, a robust method for the synthesis of the different oligosaccharide epitopes is required. Here, we report the gram-scale syntheses of both types of epitopes by an approach that utilizes glucosyl trichloroacetimidate donor 2 to first create a beta-glucopyranoside linkage and then epimerizes the C-2 center via an oxidation-reduction sequence that provides an efficient multigram scale route to the beta-mannopyranosides 5, 8, and 15. Reaction of glycosides 16-18 with homobifunctional adipic acid p-nitrophenyl diesters in dry DMF gave the corresponding half esters in good yields, and of sufficient stability to permit chromatographic purification. Subsequent conjugation with BSA and tetanus toxiod (TT) under mild conjugation conditions afforded the corresponding tri- and tetrasaccharide neoglycoproteins with good efficiency. The conjugation method is also applicable to the coupling of small amounts (mg) of larger oligosaccharides with different proteins.