Oligosaccharide moieties of human milk glycans that inhibit pathogens

描述(申请人提供)：现在有强有力的数据支持我们早期的假设，即母乳喂养婴儿肠道疾病发病率的降低部分归因于人类乳多糖的保护。葡聚糖包括糖蛋白、糖脂、粘蛋白和糖胺聚糖，含有与蛋白质、脂类和其他分子骨架相连的复杂低聚糖结构。这些复杂的碳水化合物部分是由乳腺中的许多糖基转移酶合成的，那些与细胞表面糖共轭病原体受体同源的糖链可能会抑制病原体的结合，从而保护哺乳的婴儿。轮状病毒和HIV在婴儿中的感染主要通过口服接种，我们发现这些致病病毒在体外可被特定的高相对分子质量的人乳多糖强烈抑制。在固相分析和人类白细胞中，人乳糖胺多聚糖、硫酸软骨素和人乳硫酸糖鞘脂组分的一部分都强烈地抑制HIV。人乳糖蛋白乳胶粘附素(46 KDa)对轮状病毒感染MA 104细胞有很强的抑制作用，这个分子解释了人乳在体外对轮状病毒的所有抑制作用。这项建议侧重于利用最近出现的最先进的仪器分析技术来表征这些具有抗病毒活性的多糖，并可以提供对复杂多糖部分的分子结构的详细了解。将研究其分子机制，包括全分子对多种病原体的抑制作用。接下来将进行研究，以确定活性分子中最小的活性部分，并确认它们抑制病原体的机制。这些研究旨在最终制定一项计划，通过基因工程来合成乳酸克鲁维酵母的活性部分。乳酸克鲁维酵母是一种天然存在于人类饮食中的许多乳制品中的酵母，事实证明，这种酵母适合合成其他活性人类乳多糖。可用于口服的、可抑制艾滋病毒或轮状病毒的合成人乳多糖的供应，可能会对这些对公众健康的重要威胁产生重大影响。

DESCRIPTION (provided by applicant): There is now strong data supporting our early hypothesis that the reduced incidence of enteric diseases in breastfeeding infants is due, in part, to protection by human milk glycans. Glycans, including glycoproteins, glycolipids, mucins, and glycosaminoglycans, contain complex oligosaccharide structures attached to proteins, lipids, and other molecular backbones. These complex carbohydrate moieties are synthesized by the many glycosyltransferases in the mammary gland; those glycans with homology to cell surface glycoconjugate pathogen receptors may inhibit pathogen binding, thereby protecting the nursing infant. Rotavirus and HIV infections in infants are introduced primarily through oral inoculation, and we discovered that these pathogenic viruses are strongly inhibited by specific high molecular weight human milk glycans in vitro. A subset of the human milk glycosaminoglycans, a chondroitin sulfate, and a component of the human milk sulfated glycosphingolipid fraction each strongly inhibit HIV in solid phase assays and in human leukocytes. A human milk glycoprotein, lactadherin (46 kDa), strongly inhibits rotavirus infection of MA 104 cells, and this molecule accounts for all of the inhibitory activity of human milk against rotaviruses in vitro. This proposal focuses on characterizing these actively antiviral glycans, using state-of-the-art instrumental analytical techniques that have recently become available and can provide detailed understanding of the molecular structure of complex glycan moieties. The molecular mechanisms will be studied to include the inhibition of multiple strains of the pathogens by the whole molecules. This will be followed by research to identify the smallest active moieties of the active molecules, and confirming their mechanism of pathogen inhibition. These studies are designed to culminate in a plan to synthesize the active moieties through genetic engineering of Kluyveromyces lactis, yeast occurring naturally in many dairy products of the human diet, and which has proved amenable to synthesis of other active human milk glycans. The availability of synthetic human milk glycans suitable for oral consumption that inhibit HIV or rotavirus could have large impact on these important threats to public health.