SECRETORY COMPONENT--STRUCTURE/FUNCTION/GENETICS

长期目标是定义秘书的结构特征 对其参与分泌很重要的成分(SC) 免疫系统。SC，一种由外分泌腺上皮合成的糖蛋白 细胞作为跨膜蛋白，作为基底外侧的受体 上皮细胞的膜；在这里它与聚合物Ig结合。这个 免疫球蛋白-SC复合体被内吞，跨上皮细胞运输 分泌囊泡，并释放为分泌物。在之后的某个时间 SC的受体形式与聚合物Ig的相互作用，受体SC是 显然是裂解的，因此SC释放到分泌物中(作为 自由SC或结合到聚合物Ig上的As SC)显著小于 跨膜形式。兔显然有两种大小的膜形成SC (120kd和95kd)和2种大小的分泌物SC(80kd和55kd)。在……里面 此外，兔具有SC(T61和T62)的异型变体，表现出 有1-2kd的微小尺寸差异。细微的大小差异和 T61和T62同种异型在80例中均存在抗原性差异 Kd和55kd形式的分泌型SC。本提案中所述的研究 会利用分泌物中多种形式的兔SC 比较结构差异和功能差异，并确定 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(HPLC)和 将使用2-D薄层技术。此外，大量的 将为氨基酸制备80kd形式的T61SC和55kd形式的T61SC 序列研究。比较功能研究将由两名学生完成 手段：1)不同形式的SC对 二聚体免疫球蛋白A的测定和2)各组分的相对容量 将评估保护IgA免受蛋白质降解的SC的形式。 SC和二聚体IgA的非共价和共价相互作用将是 被研究的反应物和产物，用于结合研究和蛋白质分解 降解研究将通过高效液相色谱法和免疫化学方法进行分析。 技巧。遗传学研究将被扩展到进一步表征一种 兔SC的额外遗传变异(T63)，似乎是 由T-基因座的第三个等位基因控制。几个兔子聚居地将是 调查以确定T61、T62和T63的频率和 其他变异的频率。对变种的鉴定将是 由免疫化学(放射免疫分析)和物理化学(SDS-PAGE)完成 技巧。

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.