BIOLOGY OF THE HUMAN GLYCOPHORIN BLOOD GROUP ANTIGENS

血型糖蛋白A是人红细胞表面的主要糖蛋白 并且含有一个N-聚糖和多个O-聚糖。 血型糖蛋白B，一种高度 人红细胞上的同源糖蛋白，仅含有O-聚糖。 虽然适当的糖基化对于细胞表面表达至关重要 血型糖蛋白A，负责这种作用的机制不是 明白 血型糖蛋白A和B在免疫治疗的实践中是重要的。 输血药物，因为它们携带多种人类血型抗原， 并且这些抗原的抗体可引起溶血性输血反应， 新生儿溶血病和自身免疫性溶血性贫血。 然而，很少有研究考察 人多克隆和小鼠单克隆抗体与这些抗体的结合 分子。 血型糖蛋白A和B也具有医学重要性，因为 它们作为疟原虫入侵的红细胞表面受体 恶性疟原虫裂殖子 由于很难获得突变体 在氨基酸序列中具有确定变异的血型糖蛋白分子， 寡糖结构，对这种宿主细胞的详细了解- 寄生虫的相互作用尚不可用。 当前的目标 建议是研究细胞生物学，免疫学和受体功能 人血型糖蛋白抗原： 1. 确定N-聚糖和O-聚糖在 血型糖蛋白A细胞内转运。 2. 使用重组DNA方法来检查小鼠和人的免疫 对血型糖蛋白A和B的应答，和 3. 测定血型糖蛋白A的肽和碳水化合物部分， B，被人类疟疾寄生虫识别。 这些目标将通过使用一系列稳定转染的细胞来实现。 表达野生型或变体血型糖蛋白A或B的cDNA的品系。 新 突变血型糖蛋白A和B cDNA将通过定点克隆构建， 诱变 B=y在两个正常中国仓鼠卵巢中表达cDNA 成纤维细胞和糖基化缺陷的细胞， 产生在氨基酸和氨基酸上都不同的变异血型糖蛋白， 碳水化合物序列 将构建噬菌体展示文库， 检测小鼠对血型糖蛋白A的免疫应答。 这将决定 免疫反应是否受到限制，是否也会导致 构建新的临床有用的血清学试剂。 总的来说， 这些研究将导致对细胞生物学的更好理解， 免疫学和血型糖蛋白A和B的受体功能。

Glycophorin A is the major glycoprotein on the human erythrocyte surface and contains one N-glycan and multiple O-glycans. Glycophorin B, a highly homologous glycoprotein on human erythrocytes, contains only O-glycans. Although appropriate glycosylation is crucial for cell surface expression of glycophorin A, the mechanism responsible for this effect is not understood. Glycophorin A and B are important in the practice of transfusion medicine since they carry multiple human blood group antigens, and antibodies to these antigens can cause hemolytic transfusion reactions, hemolytic disease of the newborn,a nd autoimmune hemolytic anemia. However, there have been few studies examining the fine specificity of binding of human polyclonal and mouse monoclonal antibodies to these molecules. Glycophorins A and B are also of medical importance because they serve as erythrocyte surface receptors for the invasion of Plasmodium falciparum malaria merozoites. Due to the difficulty in obtaining mutant glycophorin molecules with defined variaitons in amino acid sequence and oligosaccharide structure, a detailed understanding of this host cell- parasite interaction is not yet available. The goals of the current proposal are to study the cell biology, immunology, and receptor function of the human blood group glycophorin antigens by: 1. determining the role that the N-glycans and O-glycans play in intracellular transport of glycophorin A. 2. using recombinant DNA approaches to examine the murine and human immune response to glycophorins A and B, and 3. determining the peptide and carbohydrate portions of glycophorins A and B that are recognized by human malaria parasites. These goals will be achieved by using a series of stably transfected cell lines expressing cDNA of wild type or variant glycophorin A or B. New mutant glycophorin A and B cDNAs will be constructed by site-directed mutagenesis. B=y expressing the cDNAs in both normal Chinese hamster ovary fibroblasts and those with defects in glycosylation, it is possible to create variant glycophorins that differ in both amino acid and carbohydrate sequence. Phage display libraries will be constructed to examine the murine immune response to glycophorin A. This will determine whether the immune response is restricted and will also result in athe construction of new clinically useful serological reagents. In summary, these studies will result in greater understanding of the cell biology, immunology, and receptor function of glycophorins A and B.