Dodds A W, Law S K, Porter R R
Immunogenetics. 1986;24(5):279-85. doi: 10.1007/BF00395532.
Human complement component C4 is coded by two genes situated between HLA-D and HLA-B. Both genes are highly polymorphic; C4-A gene products normally carry the blood group antigen Rodgers and C4-B proteins usually carry the Chido antigen. Using a monoclonal antibody which binds Rodgers-positive and Chido-positive proteins with different affinities, we have purified a number of less common C4 allotypes and compared their properties. All C4-B allotypes tested have similar specific hemolytic activities and binding efficiencies to small molecules. All C4-A proteins tested had similar binding to small molecules and hemolytic activities except for the C4-A6 proteins from two individuals with different extended haplotypes, both of which had identical hemolytic activities and much lower ones than other C4-A allotypes. Two allotypes, C4-A1, Rodgers-negative but Chido-positive, and C4-B5, Chido-negative but probably Rodgers-positive, were found to behave as typical C4-A and C4-B proteins, respectively, apart from the switch in their antigenic properties.
人类补体成分C4由位于HLA - D和HLA - B之间的两个基因编码。这两个基因都具有高度多态性；C4 - A基因产物通常携带血型抗原Rodgers，而C4 - B蛋白通常携带Chido抗原。我们使用一种对Rodgers阳性和Chido阳性蛋白具有不同亲和力的单克隆抗体，纯化了一些较罕见的C4同种异型，并比较了它们的特性。所有测试的C4 - B同种异型对小分子具有相似的特异性溶血活性和结合效率。除了来自两个具有不同扩展单倍型个体的C4 - A6蛋白外，所有测试的C4 - A蛋白对小分子的结合和溶血活性都相似，这两种C4 - A6蛋白具有相同的溶血活性，且比其他C4 - A同种异型的溶血活性低得多。发现两种同种异型，即C4 - A1（Rodgers阴性但Chido阳性）和C4 - B5（Chido阴性但可能Rodgers阳性），除了抗原特性发生转换外，分别表现为典型的C4 - A和C4 - B蛋白。
