Purification and characterization of the pig analogue of human membrane cofactor protein (CD46/MCP).
Purification and characterization of the pig analogue of human membrane cofactor protein (CD46/MCP).
复制标题
人膜辅因子蛋白猪类似物 (CD46/MCP) 的纯化和表征。
DOI：
10.4049/jimmunol.158.4.1703
复制
发表时间：
1997
影响因子：
4.4
通讯作者：
B. Morgan
中科院分区：
文献类型：
--
作者：
C. W. van den Berg;J. Perez de la Lastra;D. Llanes;B. Morgan
对猪淋巴细胞产生一组单克隆抗体。7个单抗免疫沉淀出50- 60kda的膜结合蛋白。这种蛋白被称为JM4C8-Ag，在多种细胞上表达，包括所有循环细胞和成纤维细胞、上皮细胞和内皮细胞。JM4C8-Ag是跨膜锚定和糖基化的。其中一种抗体用免疫亲和层析法从红细胞膜中分离出JM4C8-Ag。通过前28个残基的n端氨基酸分析显示，与人补体调节分子膜辅助因子蛋白（MCP; CD46）同源性为43%。纯化后的蛋白具有辅助因子活性，可介导人、猪C3b蛋白的i介导裂解，证实其为猪MCP类似物。纯化后的蛋白在激活经典途径或替代途径后，还能强烈抑制人补体和猪补体对兔红细胞的裂解。这是关于MCP的非灵长类类似物的首次报道。在猪细胞上存在一种能够作为辅助因子控制人类补体激活的常驻MCP，这对猪器官在异种移植中的使用产生了影响。
A panel of mAbs were raised against pig lymphocytes. Seven mAbs immunoprecipitated a 50- to 60-kDa membrane-bound protein. This protein, termed JM4C8-Ag, was expressed on a wide variety of cells, including all circulating cells and cells of fibroblast, epithelial, and endothelial origin. The JM4C8-Ag was transmembrane-anchored and glycosylated. One of the Abs was used in immunoaffinity chromatography to isolate JM4C8-Ag from erythrocyte membranes. N-terminal amino acid analysis through the first 28 residues showed a 43% homology with the human complement regulatory molecule membrane cofactor protein (MCP; CD46). The purified protein had cofactor activity for factor I-mediated cleavage of human and pig C3b, confirming its identity as the pig analogue of human MCP. The purified protein also strongly inhibited lysis of rabbit erythrocytes by human and pig complement after activation of the classical or alternative pathway. This is the first report of a nonprimate analogue of MCP. The presence of a resident MCP on pig cells capable of acting as a cofactor in the control of human complement activation has consequences for the use of pig organs in xenotransplantation.