Weis J J, Richards S A, Smith J A, Fearon D T
J Immunol Methods. 1986 Aug 21;92(1):79-87. doi: 10.1016/0022-1759(86)90506-5.
The human C3d receptor (complement receptor type 2, CR2), that also serves as the B lymphocyte receptor for the Epstein-Barr virus, was purified from detergent lysates from the B lymphoblastoid cell lines, SB and Raji, by monoclonal antibody affinity chromatography using the anti-CR2 monoclonal antibody, HB-5. Relative to the concentration of cellular protein and receptor that was initially solubilized by detergent, the procedure provided a 37,000-fold purification with a 40-50% recovery of CR2. The purified receptor presented a single Coomassie blue-stained band when analyzed by SDS-PAGE, and it retained its function of binding to C3-Sepharose. The N-terminus of CR2 was blocked. The amino acid composition was significantly similar to that of the C3b/C4b receptor, factor H and C4 binding protein, suggesting that CR2 may be a member of this newly defined protein family. However, CR2 did not exhibit the regulatory functions of these proteins, namely, the decay dissociation of the classical or alternative pathway C3 convertases and serving as a cofactor for the cleavage of C3b.
人类C3d受体（补体受体2型，CR2）也是爱泼斯坦-巴尔病毒的B淋巴细胞受体，使用抗CR2单克隆抗体HB-5，通过单克隆抗体亲和层析从B淋巴母细胞系SB和Raji的去污剂裂解物中纯化得到。相对于最初被去污剂溶解的细胞蛋白和受体的浓度，该方法实现了37000倍的纯化，CR2的回收率为40%-50%。通过SDS-PAGE分析时，纯化后的受体呈现出一条考马斯亮蓝染色带，并且保留了与C3-琼脂糖结合的功能。CR2的N端被封闭。其氨基酸组成与C3b/C4b受体、H因子和C4结合蛋白的氨基酸组成显著相似，这表明CR2可能是这个新定义的蛋白质家族的成员。然而，CR2并未表现出这些蛋白的调节功能，即经典或替代途径C3转化酶的衰变解离以及作为C3b裂解的辅助因子。
