Monoclonal antibodies directed to a disulfated glycosphingolipid, SB1a (GgOse4Cer-II3IV3-bis-sulfate), associated with human hepatocellular carcinoma.
Two murine monoclonal antibodies, 2H6G5 (IgM) and 4A9E10 (IgG3), were obtained by using either cultured human hepatocellular carcinoma cells (PLC/PRF/5) or the acidic glycolipid mixture prepared from the same cells as immunogens. The antigen in PLC/PRF/5 cell membranes recognized by both antibodies was identified as a disulfated acidic glycolipid, GgOse4Cer-II3IV3-bis-sulfate (SB1a). Both antibodies reacted specifically with SB1a, and no significant reactivity was noted with other sulfated glycolipids or gangliosides except that the antibody 2H6G5 showed a weak cross-reactivity with LacCer-II3-sulfate (SM3), another sulfated glycolipid which partly shares the same carbohydrate structure as SB1a. The SB1a antigen is a relatively minor glycolipid in PLC/PRF/5 cells, but it was strongly expressed at the surface of PLC/PRF/5 cells as ascertained by cytofluorometry using both antibodies. A significant amount of SB1a antigen was present in 3 of the acidic glycolipid fractions isolated from 15 human hepatocellular carcinoma tissues as well as in the acidic glycolipid fraction prepared from PLC/PRF/5 cells, while all the acidic glycolipid fractions prepared from cirrhotic livers and a normal liver were essentially negative for SB1a, as ascertained by both solid phase enzyme immunoassay and the thin-layer chromatography-immunostaining method. These results strongly suggest that the SB1a antigen as defined by these new monoclonal antibodies is associated with human hepatocellular carcinoma.
Hiraiwa
N
N
Department of Clinical Science and Laboratory Medicine, Kyoto University, School of Medicine, Japan.
Iida
N
N
Ishizuka
I
I
Itai
S
S
Shigeta
K
K
Kannagi
R
R
Fukuda
Y
Y
Imura
H
H
D000818:Animals; D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm / Q000032:analysis*; D006528:Carcinoma, Hepatocellular / Q000276:immunology*; D006017:Glycolipids / Q000032:analysis*; D006028:Glycosphingolipids / Q000032:analysis* / Q000276:immunology; D006801:Humans; D008113:Liver Neoplasms / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C
D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm; D006017:Glycolipids; D006028:Glycosphingolipids; C011117:sulfoglycolipids