Function of gastro-intestinal mucin-derived acidic oligosaccharaides recognized by anti-mucin monoclonal antibodies

我们用纯化的猪胃粘蛋白免疫小鼠，制备了一种单克隆抗体，命名为PGM34。PGM34识别出粘蛋白的碳水化合物部分。采用凝胶过滤、离子交换、正相高效液相色谱法对猪胃黏液中低聚糖醛醇进行分离，并与PGM34进行反应性检测。与PGM34反应得到两种纯化的低聚糖醛醇，核磁共振波谱法测定其结构为：Fucα1-2Galβ1-4GlcNAc(6SO_3H)β1-6(Fucα1-2Galβ1-3)GalNAc-ol和Fucα1-2-Galβ1-4GlcNAc (6SO_3H)β1-6(Galβ1-3)Gal-NAc-ol。这些低聚糖的脱焦或脱硫形式都不会与PGM34发生反应。由此确定PGM34的表位为Fucα1-2Galβ1-4GlcNAc (6SO_3H)β-序列。大鼠胃肠道免疫组化观察显示，PGM34对胃底和小肠杯状细胞附近的表面黏液细胞有明显的染色作用，对胃窦黏液细胞有轻微的染色作用。这些数据综合在一起，表明PGM34是一个非常有用的工具，揭示具有特征硫酸寡糖的粘蛋白的作用。采用5-氟尿嘧啶（5- fu）给药5 d，观察抗肿瘤化疗致小肠损伤。PGM34免疫组化法观察，5-FU处理引起小肠粘液细胞数量明显减少。这种粘液细胞的减少被一种新型的h2阻滞剂拉弗丁（lafutidine）联合使用显著抑制，而不是被第一代的h2阻滞剂西咪替丁（cimetidine）联合使用。5-FU处理组大鼠小肠粘蛋白含量显著降低。这种减少被拉弗丁的共同管理显著恢复。这些结果支持拉弗定对5- fu诱导的大鼠小肠黏膜炎的疗效。少

We developed a monoclonal antibody, designated PGM34, by immunizing a mouse with purified pig gastric mucin. PGM34 recognized the carbohydrate portion of the mucins. Oligosaccharide-alditols obtained from the pig gastric mucin were fractionated by successive gel-filtration, ion-exchange, and normal phase high-performance liquid chromatography, and tested for the reactivity with PGM34. Two purified oligosaccharide-alditols reacting with PGM34 were obtained and their structures were determined by nuclear magnetic resonance spectroscopy as Fucα1-2Galβ1-4GlcNAc(6SO_3H)β1-6(Fucα1-2Galβ1-3)GalNAc-ol and Fucα1-2-Galβ1-4GlcNAc (6SO_3H) β1-6 (Galβ1-3)Gal-NAc-ol. None of the defucosylated or desulfated form of these oligosaccharides reacted with PGM34. Thus, the epitope of PGM34 was determined as the Fucα1-2Galβ1-4GlcNAc (6SO_3H)β-sequence. Immunohistochemical observations of rat gastrointestinal tracts showed that PGM34 stained the surface mucous cells close to the generative cell zone in the g … More astric fundus and the goblet cells in the small intestine, but only slightly stained the antral mucous cells in the stomach. These data, taken together, showed that PGM34 is a very useful tool to reveal the role of mucins having characteristic sulfated oligosaccharides.To investigate the antineoplastic chemotherapy-induced small intestinal injury, 5-fluorouracil(5-FU) was orally administered to rats for 5 days. The 5-FU treatment caused a significant decrease in the number of mucus cells in the small intestine observed by an immunohistochemical method using PGM34. This reduction of mucus cells was significantly inhibited by the co-administration of lafutidine, a novel H2-blocker, but not by cimetidine, an H2-blocker of the first generation. The mucin content in the small intestine significantly decreased in the 5-FU treated group. This reduction was significantly recovered by the co-administration of lafutidine. These results support the efficacy of lafutidine toward 5-FU-induced mucositis in rat small intestine. Less