The molecular basis of bovine colostrum kappa casein for inhibitory mechanism against human rotavirus infection

人类轮状病毒(HRV)是婴幼儿重症胃肠炎的主要病原。在本研究中，我们研究了牛卡伯酪蛋白(к-CN)对心率变异性病毒感染的抑制作用。к-CN是唯一一种具有O-连接糖链特征的酪蛋白。经神经氨酸酶和O-糖苷酶处理得到的脱糖酪蛋白没有表现出抗心率变异性，这表明к-CN中的O-连接糖链结构是其抗病毒活性所必需的。MALDI-TOF MS分析表明，正常奶牛产后6-7天的成熟乳和晚期初乳中к-CN糖链的组成不同。实验表明，后者的k-CN活性略高于前者，这可归因于结合碳水化合物的差异。

Human rotavirus (HRV) is a major etiologic agent of severe infantile gastroenteritis. In this study, we investigated the inhibitory effect of bovine kappa casein (к-CN) against HRV infection. к-CN is the only casein characterized with O-linked glycans. Deglycosylated casein obtained by neuraminidase and O-glycosidase treatments did not exhibit the anti-HRV activity, suggesting that O-linked glycan structure in к-CN is essential for its antivirus activity. From the analysis of MALDI-TOF MS, the composition of к-CN glycan was different between mature milk and late colostrum obtained from normal cows at 6-7 day after parturition. Experimentally indicated slightly higher activity of k-CN from the latter than that from the former could be ascribed to the difference in the attached carbohydrates.