Iida K, Mitomo K, Fujita T, Tamura N
Department of Immunology, University of Tsukuba, Ibaraki, Japan.
Immunology. 1987 Nov;62(3):413-7.
We raised 15 mouse monoclonal antibodies against human C3 from two separate fusions. Mouse plasmacytoma cells were fused with spleen cells from mice immunized either with a mixture of C3, C3b and C3c, or with a mixture of C3dg and C3d. Three of the 15 monoclonals were characterized in detail. N-7A reacted with native C3 as well as C3b and C3c. Two other monoclonals, C-5G and G-3E, recognized neoantigenic determinants on C3c and C3dg, respectively. In ELISA, C-5G reacted with C3b and C3c but not with native C3 nor with C3dg; and on the other hand G-3E reacted only with C3dg. The selective specificities of these monoclonals were further confirmed in a binding assay to C3 fragments formed on cellular intermediates. C-5G bound exclusively to EC3b, and G-3E bound to EiC3b, EC3dg and EC3d. N-7A bound only very poorly to EC3b. C-5G inhibited both the haemolytic activity of C5 convertase and also the CR1-mediated rosette formation of B-enriched peripheral mononuclear cells with EC3b. G-3E inhibited the CR2-mediated EC3dg-rosette formation of Raji cells. These monoclonals, with selective specificities, can distinguish the state of activation and degradation of the C3 molecule.
我们通过两次独立的融合制备了15种抗人C3的小鼠单克隆抗体。将小鼠浆细胞瘤细胞与用C3、C3b和C3c混合物或C3dg和C3d混合物免疫的小鼠脾细胞进行融合。对这15种单克隆抗体中的3种进行了详细表征。N-7A与天然C3以及C3b和C3c反应。另外两种单克隆抗体C-5G和G-3E分别识别C3c和C3dg上的新抗原决定簇。在酶联免疫吸附测定（ELISA）中，C-5G与C3b和C3c反应，但不与天然C3或C3dg反应；另一方面，G-3E仅与C3dg反应。这些单克隆抗体的选择性特异性在与细胞中间体上形成的C3片段的结合试验中得到进一步证实。C-5G仅与EC3b结合，G-3E与EiC3b、EC3dg和EC3d结合。N-7A与EC3b的结合非常弱。C-5G既抑制C5转化酶的溶血活性，也抑制富含B细胞的外周单核细胞与EC3b的CR1介导的玫瑰花结形成。G-3E抑制Raji细胞的CR2介导的EC3dg玫瑰花结形成。这些具有选择性特异性的单克隆抗体可以区分C3分子的激活和降解状态。
