Distribution in Tissue and Biosynthesis of ABO Blood Group Substances Specific for Tissue.

本研究首次将我们已制备的ABO血型物质组织特异性表位单克隆抗体应用于研究ABO血型物质在唾液腺中的分布。用荧光或胶体金标记的血型抗体作为第二抗体，在显微镜和电镜下观察，该抗体只与唾液腺中的粘液细胞发生反应，而不与其他灵长类动物和动物唾液腺中的粘液细胞发生反应。由于本实验所用的唾液腺是从尸体上采集的，因此ABO血型物质或其前体物质在唾液腺细胞内的分布不明显。表明该抗体识别的糖链仅在胃肠化组织中表达，而携带ABO和刘易斯血型活性的糖链也存在于该抗体所识别的糖蛋白分子上。众所周知，肠上皮化生组织的ABO和刘易斯血型活性低于正常组织，因此，抗体识别的碳水化合物链似乎是生物合成途径中对ABO和刘易斯血型有活性的碳水化合物链的前体或类似于碳水化合物的物质。利用该抗体进行亲和层析，可纯化出数百万kD的抗原糖蛋白。因此，我们考虑通过从大量胃粘膜中纯化抗原性糖蛋白，并明确该抗体所定义的糖链结构，以明确组织中ABO血型物质的生物合成途径。

In this study, the monoclonal antibody defining tissue-specific epitope on the ABO blood group substances in salvia, which has been already produced by us, was first applied for investigation to the distribution of the ABO blood group substances in salival gland. In the microscopic and electron microscopic observation using fluorescence or gold colloid conjugated blood group antibody as a second antibody, the antibody reacted with only mucous cells in salival gland, but not react with the the those in salival gland of other primates and animals. Unfortunately, the intracellular distribution of the ABO blood group substances or its precursors ws not obvious, since salival gland used in this experiment was collected from cadavers.Next, we established a monoclonal antibody specific for intestinal metaplasia. It was made clear that the antibody recognized the carbohydrate chain expressing in only intestinal metaplasia of stomach, and that the carbohydrate chain carrying ABO and Lewis blood group activities also existed on the glycoprotein molecules defined by the antibody. Since it is well known that the tissue of intestinal metaplasia shows lower activity of ABO and Lewis blood groups than normal tissues, it seems that the carbohydrate chain recognized by the antibody is a precursor or a precursor-like material of the carbohydrate chain active to ABO and Lewis blood groups in the biosynthetic pathway. Furthermore, about millions kD antigenic glycoprotein could be purified in the affinity chromatography using the antibody. Therefore, we consider to clear biosynthetic pathway of the ABO blood group substances in the tissue by purifying of the antigenic glycoprotein from a large amount of gastric mucosa, and by making out obvious the structure of the carbohydrate chain defined by this antibody.