Pardridge W M, Yang J, Eisenberg J, Mietus L J
J Cereb Blood Flow Metab. 1986 Apr;6(2):203-11. doi: 10.1038/jcbfm.1986.33.
To begin elucidating the biochemical basis of the polarized membrane features of the blood-brain barrier (BBB), a series of immunochemical and immunoperoxidase studies were initiated with bovine brain microvessels that make up the BBB in vivo. A rabbit antiserum was prepared against isolated bovine brain BBB plasma membranes. The bovine microvessel plasma membranes were radioiodinated with chloramine-T, and the antiserum selectively immunoprecipitated a 46K protein. The antibodies directed against the 46K protein were quantitatively absorbed with bovine brain capillaries but not with rat kidney or liver powder. Only the capillaries of brain reacted with the rat kidney-absorbed antiserum in immunoperoxidase studies of ethanol-fixed, 8-micron sections of bovine brain cortex, whereas the capillaries in heart, liver, and kidney did not react. This antiserum also strongly illuminated the lateral membranes of isolated bovine brain capillary endothelial cells grown in primary tissue culture. These studies provide evidence for a polarized distribution of a surface antigen in bovine brain capillary endothelial cells that is not present in capillary endothelia of liver, heart, or kidney. The correlation of the immunoperoxidase and immunoprecipitation techniques suggests that a candidate for the asymmetrically distributed surface antigen in the BBB is the 46K protein. The relationship between the 46K protein and the composition of BBB tight junctions remains to be determined.
为了开始阐明血脑屏障（BBB）极化膜特征的生化基础，我们对构成体内血脑屏障的牛脑微血管开展了一系列免疫化学和免疫过氧化物酶研究。制备了一种针对分离出的牛脑血脑屏障质膜的兔抗血清。用氯胺 - T对牛微血管质膜进行放射性碘化，该抗血清选择性地免疫沉淀出一种46K蛋白。针对46K蛋白的抗体可被牛脑毛细血管定量吸收，但不能被大鼠肾脏或肝脏粉末吸收。在对乙醇固定的牛脑皮质8微米切片进行免疫过氧化物酶研究时，只有脑毛细血管与经大鼠肾脏吸收的抗血清发生反应，而心脏、肝脏和肾脏中的毛细血管则无反应。这种抗血清还强烈显示出在原代组织培养中生长的分离牛脑毛细血管内皮细胞的侧膜。这些研究为牛脑毛细血管内皮细胞中一种表面抗原的极化分布提供了证据，这种表面抗原在肝脏、心脏或肾脏的毛细血管内皮中不存在。免疫过氧化物酶和免疫沉淀技术的相关性表明，血脑屏障中不对称分布的表面抗原的一个候选者是46K蛋白。46K蛋白与血脑屏障紧密连接的组成之间的关系仍有待确定。
