Shimamura T, Nakamura T, Koyama J
Mol Immunol. 1987 Jan;24(1):67-74. doi: 10.1016/0161-5890(87)90112-x.
As reported in a previous paper by the authors (J. Biochem. 99, 227-235, 1986), the Fab' of a monoclonal antibody, VIA2 IgG1, prepared by fusion of splenic cells of a mouse immunized with guinea-pig peritoneal macrophages with a myeloma cells line, completely inhibits the binding of ovalbumin (OA)-complexed IgG1 antibody to macrophages, but only partially the binding of OA-complexed IgG2 antibody. Based on these results, it was proposed that the cells have at least two types of Fc receptor (FcR) for homologous IgG isotypes: FcR2 for IgG2 and FcR1.2 for both IgG2 and IgG1, and also that VIA2 IgG1 is anti-FcR1.2 antibody. Thereafter, complete inhibition of the binding of OA-complexed IgG2 antibody to macrophages occurred when the Fab' of another monoclonal antibody, VIIA1 IgG1 was added to the Fab' of VIA2 IgG1, whereas the former did not affect the binding of OA-complexed IgG1 antibody. This effect of the Fab' of VIIA1 IgG1 indicates that VIIA1 IgG1 is a monoclonal antibody capable of selectively blocking the binding of OA-complexed IgG2 antibody to FcR2. When the antigen of VIIA1 IgG1 was isolated by affinity chromatography on the F(ab')2 of the antibody coupled to Sepharose, it gave a single band with a mol. wt of 52,000 on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. It moved slightly faster than the FcR1.2 with a mol. wt of 55,000, which was isolated by the use of VIA2 IgG1, and corresponded to the fast moving portion of the broad band of FcRs isolated with OA-complexed IgG2 antibody. These results strongly suggest that VIIA1 IgG1 is a monoclonal antibody to FcR2.
正如作者之前的一篇论文（《生物化学杂志》99卷，227 - 235页，1986年）所报道的，通过将用豚鼠腹腔巨噬细胞免疫的小鼠脾细胞与骨髓瘤细胞系融合制备的单克隆抗体VIA2 IgG1的Fab'，能完全抑制卵清蛋白（OA）复合IgG1抗体与巨噬细胞的结合，但只能部分抑制OA复合IgG2抗体的结合。基于这些结果，有人提出细胞对于同源IgG同种型至少有两种类型的Fc受体（FcR）：针对IgG2的FcR2和针对IgG2及IgG1的FcR1.2，并且VIA2 IgG1是抗FcR1.2抗体。此后，当另一种单克隆抗体VIIA1 IgG1的Fab'添加到VIA2 IgG1的Fab'中时，OA复合IgG2抗体与巨噬细胞的结合被完全抑制，而前者不影响OA复合IgG1抗体的结合。VIIA1 IgG1的Fab'的这种作用表明VIIA1 IgG1是一种能够选择性阻断OA复合IgG2抗体与FcR2结合的单克隆抗体。当通过在偶联到琼脂糖的抗体的F(ab')2上进行亲和层析分离VIIA1 IgG1的抗原时，在十二烷基硫酸钠 - 聚丙烯酰胺凝胶电泳上它呈现出一条分子量为52,000的单一带。它的迁移速度比通过使用VIA2 IgG1分离的分子量为55,000的FcR1.2略快，并且与用OA复合IgG2抗体分离的FcR宽带的快速迁移部分相对应。这些结果有力地表明VIIA1 IgG1是针对FcR2的单克隆抗体。
