Detachment of cell surface-bound anticarcinoembryonic antigen immune complexes by phospholipase C.
CEA as well as normal cross-reacting antigens (NCA) are fixed to the cell membrane via phosphatidylinositol (PI). To find out whether these antigens are internalized after antibody contact, acid pH desorption was compared to phospholipase C (PLC)-mediated cleavage of the antigen anchor. With the former procedure, marked differences in the desorbability of individual MAbs were noted, while PLC was able to cleave off surface-bound immune complexes irrespective of the MAb involved. From this it is concluded that internalization of MAb complexes of CEA/NCA, if occurring at all, is a low efficiency process.
Matzku
S
S
Institute of Radiology, German Cancer Research Center, Heidelberg.
Mach
J P
JP
Buchegger
F
F
Moldenhauer
G
G
Stadler
M
M
Kalthoff
H
H
D000911:Antibodies, Monoclonal / Q000276:immunology; D000936:Antigen-Antibody Complex / Q000378:metabolism*; D002272:Carcinoembryonic Antigen / Q000276:immunology*; D002460:Cell Line; D002462:Cell Membrane / Q000276:immunology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D010716:Phosphatidylinositols / Q000378:metabolism; D014407:Tumor Cells, Cultured; D010738:Type C Phospholipases / Q000378:metabolism*
D000911:Antibodies, Monoclonal; D000936:Antigen-Antibody Complex; D002272:Carcinoembryonic Antigen; D010716:Phosphatidylinositols; D010738:Type C Phospholipases