SECRETORY COMPONENT--STRUCTURE/FUNCTION/GENETICS

分泌成分——结构/功能/遗传学

• 批准号: 3285707
• 负责人: W CAREY HANLY
• 金额: $ 10.09万
• 依托单位: UNIVERSITY OF ILLINOIS AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 1984
• 资助国家: 美国
• 起止时间: 1984-08-01 至 1988-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3285707
• 关键词: X ray crystallography; alleles; animal population genetics; basolateral membrane; chemical fingerprinting; covalent bond; epithelium; gel electrophoresis; gene frequency; high performance liquid chromatography; immunodiffusion; immunoglobulin A; molecular weight; pinocytosis; radioimmunoassay; receptor mediated endocytosis; secretion; secretory immune system; sulfation; thin layer chromatography; tyrosine

The long term goal is to define the structural features of Secretory Component (SC) that are important for its participation in the secretory immune system. SC, a glycoprotein synthesized by exocrine gland epithelial cells as a transmembrane protein, serves as a receptor on the basolateral membrane of epithelial cells; here it combines with polymeric Ig. The Ig-SC complexes are endocytosed, transported across the epithelial cell in secretory vesicles, and released into secretions. At some time after interaction of the receptor form of SC and polymeric Ig, the receptor SC is apparently cleaved so that the SC released into the secretions (either as free SC or as SC bound to polymeric Ig) is significantly smaller than the transmembrane form. Rabbits apparently have 2 sizes of membrane form SC (120 kd and 95 kd) and 2 sizes of secreted form SC (80 kd and 55 kd). In addition rabbits have allotypic variants of SC (t61 and t62) which exhibit a minor size difference of 1-2 kd. The minor size differences and the antigenic differences of t61 and t62 allotypes are present in both the 80 kd and 55 kd forms of secreted SC. The studies described in this proposal will take advantage of the multiple forms of rabbit SC in the secretions to compare structural differences and functional differences and to identify structure-function correlates. Comparative structural studies will be done by peptide mapping; both High Performance Liquid Chromatography (HPLC) and 2-D thin layer techniques will be used. In addition, large quantities of the 80 kd form and the 55 kd form of t61 SC will be prepared for amino acid sequence studies. Comparative functional studies will be done by two means: 1) relative binding abilities of the various forms of SC for dimeric IgA will be determined and 2) relative capacities of the various forms of SC to protect IgA from proteolytic degradation will be assessed. Both non-covalent and covalent interactions of SC and dimeric IgA will be studied, reactants and products for binding studies and for proteolytic degradation studies will be analyzed by HPLC and by immunochemical techniques. Genetic studies will be extended to further characterize an additional genetic variant (t63) of rabbit SC which appears to be controlled by a 3rd allele at the t-locus. Several rabbit colonies will be surveyed to determine the frequencies of t61, t62, and t63 and the frequencies of additional variants. Identification of variants will be done by immunochemical (radioimmunoassay) and physicochemical (SDS-PAGE) techniques.

长期目标是确定分泌系统的结构特征 成分（SC），这是重要的，它参与分泌 免疫系统 SC是一种由外分泌腺上皮细胞合成的糖蛋白 细胞作为跨膜蛋白，作为基底外侧的受体 上皮细胞的膜;此处它与聚合的IG结合。 的 Ig-SC复合物被内吞，转运通过上皮细胞， 分泌囊泡，并释放到分泌物中。 之后的某个时间 通过SC的受体形式与聚合物IG的相互作用，受体SC 显然裂解，使SC释放到分泌物（无论是作为 游离SC或与聚合物IG结合的SC）显著小于 跨膜型 兔子显然有2种大小的膜形式SC (120 kd和95 kd）和2种大小的分泌型SC（80 kd和55 kd）。 在 此外，兔具有SC的同种异型变体（t61和t62）， 1 - 2kD的微小尺寸差异。 微小的尺寸差异和 t61和t62同种异型的抗原性差异存在于这80个 kd和55 kd形式的分泌型SC。 将利用分泌物中多种形式的兔SC， 比较结构差异和功能差异， 结构-功能相关。 将进行比较结构研究 通过肽图谱;高效液相色谱法（HPLC）和 将使用二维薄层技术。 此外，大量的 将制备t61 SC的80 kd形式和55 kd形式用于氨基酸 序列研究 比较功能研究将由两个 意思是：1）各种形式的SC对以下的相对结合能力： 二聚体IgA将被确定，和2）各种免疫球蛋白的相对能力， 将评估保护IgA免受蛋白水解降解的SC形式。 SC和二聚体IgA的非共价和共价相互作用都将是 研究，用于结合研究和蛋白水解的反应物和产物 将通过HPLC和免疫化学法分析降解研究 技术. 遗传学研究将进一步扩展到表征 兔SC的其他遗传变异体（t63）， 由t基因座上的第三个等位基因控制。 几个兔子殖民地将 调查以确定t61、t62和t63的频率， 其他变体的频率。 变体的识别将 通过免疫化学（放射免疫测定）和物理化学（SDS-PAGE）进行 技术.