Cambier J C, Butler J E
J Immunol. 1976 Apr;116(4):994-9.
Two proteins were isolated from rat milk by using ion-exchange and gel filtration chromatography and shown to be secretory components by the criteria of: a) occurrence as free proteins in exocrine secretions, as well as bound to exocrine IgA while absent from serum and serum IgA, b) immunohistochemical localization in the epithelial cells of the gut, c) dissociability from and in vitro binding to 11 S SIgA, d) cross-reactivity with antisera to mouse and bovine secretory components, and e) significant peptide homology with bovine secretory component. The secretory components were immunochemically and physicochemically distinct as shown by: a) the lack of cross-reactivity between their specific antisera and differential reactivity with anti-bovine FSC and anti-mouse SC, b) different electrophoretic mobilities, c) DEAE elution profiles, d) carbohydrate contents, e) molecular weights, and f) apparent polypeptide chain constitution. Another interesting difference in the two is that only one of the components dissociates spontaneously from SIgA. Possible functions of two secretory components are discussed.
通过离子交换和凝胶过滤色谱法从大鼠乳汁中分离出两种蛋白质，根据以下标准表明它们是分泌成分：a）作为外分泌分泌物中的游离蛋白质存在，以及与外分泌IgA结合，而血清和血清IgA中不存在；b）在肠道上皮细胞中的免疫组织化学定位；c）与11S SIgA的体外结合和解离能力；d）与小鼠和牛分泌成分抗血清的交叉反应性；e）与牛分泌成分的显著肽同源性。分泌成分在免疫化学和物理化学上是不同的，表现为：a）它们的特异性抗血清之间缺乏交叉反应性，以及与抗牛FSC和抗小鼠SC的差异反应性；b）不同的电泳迁移率；c）DEAE洗脱曲线；d）碳水化合物含量；e）分子量；f）表观多肽链组成。两者之间另一个有趣的差异是，只有一种成分能自发地从SIgA中解离。文中讨论了两种分泌成分可能的功能。
