Two proteins share immunological epitopes on the tumor-associated antigen 17-1A.
The mouse monoclonal antibody (mAb) 17-1A which recognizes the tumor-associated antigen 17-1A (also called EGP-40 or EpCAM) was successfully used in adjuvant therapy for colorectal carcinoma. In the 17-1A antigen analysis, we isolated not only a protein of 33 kDa (P33) which was reported as the tumor associated antigen 17-1A, but also a protein of 65 kDa (P65) using affinity chromatography from cell lysates of HCT, and another protein of 50 kDa (P50) from lysates of human colorectal tumor tissues. The mAbs 17-1A and M79 (mAb M79 recognizes a different epitope on the 17-1A antigen) both could bind P33 and P50, but only M79 bound to P65 in an enzyme-linked immunosorbant assay (ELISA). These results indicate that P33 and P50 share at least two epitopes, and a common immunological epitope exists among P33, P50 and P65, suggesting that the two new proteins (P50 and P65) are related to the tumor-associated antigen 17-1A.
Chen
Y H
YH
School of Life Science and Engineering, Tsinghua University, Beijing, PR China. Chenyh@mail.tsinghua.edu.cn
Yu
T
T
Bai
Y
Y
Zhao
N
N
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000951:Antigens, Neoplasm / Q000276:immunology / Q000302:isolation & purification*; D002846:Chromatography, Affinity; D000939:Epitopes; D006801:Humans; D051379:Mice; D008970:Molecular Weight; D009363:Neoplasm Proteins / Q000276:immunology / Q000302:isolation & purification*; D014407:Tumor Cells, Cultured
D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm; D000939:Epitopes; D009363:Neoplasm Proteins; C050928:carcinoma-associated antigen 17-1A