Binding reactivity of monoclonal anti-carcinoembryonic antigen (CEA) antibodies with cell membrane-bound CEA and with free CEA in solution.
Binding reactivities of 62 anti-CEA MAbs from 10 different research groups with cell membrane-bound CEA and with free CEA in solution were compared by inhibition of MAb binding to CEA-expressing tumor cells by free CEA. Bindings of 30 MAbs to the cell membrane-bound CEA (280 ng CEA/2 x 10(5) cells) were inhibited by approximately equal amounts of free CEA, indicating that binding affinities of about half the MAbs for cell membrane-bound CEA are similar to those for free CEA, respectively. Bindings of 15 MAbs to the cell membrane-bound CEA were easily inhibited by free CEA of less than half the amount of the cell membrane-bound CEA, while inhibition of bindings of the remaining 17 MAbs required twice more free CEA than the amount of cell membrane-bound CEA, showing that about one-fourth of the MAbs have higher affinities for free CEA and the remaining about one-fourth of the MAbs possess higher affinities for cell membrane-bound CEA. These results help form the basis for selecting the anti-CEA MAbs for use in clinical applications, such as serum CEA assay, tumor imaging and immunotherapy.
Murakami
M
M
First Department of Biochemistry, School of Medicine, Fukuoka University, Fukuoka, Japan.
Kuroki
M
M
Arakawa
F
F
Haruno
M
M
Kuwahara
M
M
Ozaki
H
H
Senba
T
T
Matsuoka
Y
Y
D000230:Adenocarcinoma / Q000276:immunology / Q000556:secondary; D000911:Antibodies, Monoclonal / Q000276:immunology* / Q000378:metabolism; D000915:Antibody Affinity; D000918:Antibody Specificity; D000937:Antigen-Antibody Reactions; D002272:Carcinoembryonic Antigen / Q000276:immunology* / Q000378:metabolism; D003110:Colonic Neoplasms; D017261:Glycosylphosphatidylinositols / Q000378:metabolism; D006801:Humans; D008113:Liver Neoplasms / Q000276:immunology / Q000556:secondary; D008562:Membrane Glycoproteins / Q000276:immunology* / Q000378:metabolism; D012995:Solubility; D013274:Stomach Neoplasms / Q000276:immunology / Q000473:pathology; D014407:Tumor Cells, Cultured
D000911:Antibodies, Monoclonal; D002272:Carcinoembryonic Antigen; D017261:Glycosylphosphatidylinositols; D008562:Membrane Glycoproteins