Pharmacology Department, Menarini Ricerche S.p.A, Pomezia, Rome, Italy.
Dis Markers. 2013;34(4):257-67. doi: 10.3233/DMA-130968.
The human cancer antigen 125 (CA125) is over-expressed in epithelial ovarian cancer cells and it plays a role in the pathogenesis of ovarian cancer. This protein presents a repeat region containing up to sixty tandem repeat units. The anti-CA125 monoclonal antibodies have been previously classified into three groups: two major families, the OC125-like antibodies and M11-like antibodies, and a third group, the OV197-like antibodies. A model in which a single repeat unit contains all the epitopes for these antibodies has been also proposed, even if their exact position is still undetermined. In the present work, the affinities of the monoclonal antibodies, representative of the three families, have been investigated for different CA125-recombinant repeats through Western blot analysis. Different patterns of antibody recognition for the recombinant repeats show that CA125 epitopes are not uniformly distributed in the tandem repeat region of the protein. The minimal region for the recognition of these antibodies has been also individuated in the SEA domain through the subcloning of deleted sequences of the highly recognized repeat-25 (R-25), their expression as recombinant fragments in E. coli and Western blot analysis. Obtained data have been further confirmed by ELISA using the entire R-25 as coating antigen.
人类癌症抗原 125（CA125）在卵巢癌细胞中过度表达，在卵巢癌的发病机制中发挥作用。该蛋白呈现一个含有多达六十个串联重复单元的重复区域。抗 CA125 单克隆抗体以前被分为三组：两个主要家族，OC125 样抗体和 M11 样抗体，以及第三组，OV197 样抗体。还提出了一个模型，即单个重复单元包含这些抗体的所有表位，尽管它们的确切位置仍未确定。在本工作中，通过 Western blot 分析研究了代表这三个家族的单克隆抗体对不同 CA125 重组重复的亲和力。重组重复的不同抗体识别模式表明，CA125 表位在蛋白的串联重复区域中不是均匀分布的。SEA 结构域中高度识别重复 25（R-25）的缺失序列的亚克隆及其在大肠杆菌中的表达和 Western blot 分析，确定了这些抗体识别的最小区域。通过使用整个 R-25 作为包被抗原的 ELISA 进一步证实了获得的数据。
