Nicholson-Weller A, Burge J, Austen K F
J Immunol. 1981 Nov;127(5):2035-9.
A protein with decay-accelerating activity for the classical C3 convertase, C4b2a, has been isolated on the basis of this function from guinea pig erythrocyte stroma. The isolation procedure for decay-accelerating factor of stroma (DAF-S) utilizes butanol extraction and chromatography on DEAE-Sephacel, hydroxylapatite, and phenyl Sepharose. Purified DAF-S has a m.w. of 60,000 and 65,000 on reduced and unreduced SDS gels, respectively, and exhibits m.w. of 30,000 and 175,000 on alkaline gradient gels, suggesting multiples of a 60,000-65,000 subunit. Purified DAF-S elicited a monospecific antiserum whose IgG fraction neutralized the decay-accelerating activity for C4b,2a affixed to 10(7) sheep erythrocytes (EAC1,4,2) in a dose-response fashion. The monospecific antiserum diluted up to 1:5120 agglutinated 1 x 10(6) guinea pig erythrocytes, but not sheep or human erythrocytes, suggesting that DAF-S, an integral membrane protein, has species-specific antigens that are expressed on the surface of the guinea pig erythrocyte.
基于经典C3转化酶C4b2a的衰变加速活性，已从豚鼠红细胞基质中分离出一种蛋白质。基质衰变加速因子（DAF-S）的分离过程采用丁醇提取以及在DEAE-葡聚糖凝胶、羟基磷灰石和苯基琼脂糖上进行色谱分离。纯化后的DAF-S在还原和非还原SDS凝胶上的分子量分别为60,000和65,000，在碱性梯度凝胶上的分子量分别为30,000和175,000，表明是一个60,000 - 65,000亚基的倍数。纯化后的DAF-S引发了一种单特异性抗血清，其IgG组分以剂量反应方式中和了附着在10⁷个绵羊红细胞（EAC1,4,2）上的C4b,2a的衰变加速活性。稀释至1:5120的单特异性抗血清可凝集1×10⁶个豚鼠红细胞，但不能凝集绵羊或人类红细胞，这表明作为一种整合膜蛋白的DAF-S具有在豚鼠红细胞表面表达的物种特异性抗原。
