Open AccessEpitopes Predominantly Retained on the Carcinoembryonic Antigen Molecules in Plasma of Patients with Malignant Tumors but Not on Those in Plasma of Normal Individuals
Author(s) -
Kuroki Masahlde,
Murakami Masaaki,
Wakisaka Mamie,
KropWatorek Anna,
Oikawa Shinzo,
Nakazato Hiroshi,
Kosaki Goro,
Matsuoka Yuji
Publication year - 1992
Publication title -
japanese journal of cancer research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.035
H-Index - 141
eISSN - 1349-7006
pISSN - 0910-5050
DOI - 10.1111/j.1349-7006.1992.tb01957.x
Subject(s) - epitope , carcinoembryonic antigen , monoclonal antibody , antigen , antibody , microbiology and biotechnology , chinese hamster ovary cell , chemistry , biology , immunology , cancer , biochemistry , receptor , genetics
We have previously reported that a group of monoclonal antibodies (MAbs) to carcinoembryonic antigen (CEA), designated Group F MAbs, are able to discriminate CEA in tumor tissues from normal fecal antigen 2 , a soluble form CEA‐counterpart in normal adult feces, and that the protein epitopes recognized by them are present on the domain A3‐B3 of the CEA molecule. In this study, we further investigated the molecular localization of the epitopes recognized by the Group F MAbs using three new recombinant CEA proteins with restricted domain structures expressed in Chinese hamster ovary cells, and found that the epitopes for the Group F MAbs are present on domain B3 close to the anchoring device of the CEA molecule. The epitopes for the Group F MAbs were retained on the CEA molecules in the plasma of patients with malignant tumors and on the CEA molecules spontaneously released into the culture media from established tumor cell lines. However, a large part of the CEA molecules in the plasma of normal individuals were found to lack the epitopes for the Group F MAbs. These results provide a basis for the improved cancer diagnosis by using our CEA assay system utilizing a Group F MAb, and indicate the potential clinical utility of the Group F MAbs.