| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1988: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1987: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Research Abstract |
Many monoclonal antibodies that recongnize the carbohydrate moieties of glycoconjugates have been established by imumunizing mice with human colorectal cancer cells (LS180, SW1116) and assaying antibodies with glycopeptide-coated plastic assay plates. One of such antibodies, MLS102, reacted with the colorectal cancer surface and mucinous glycoproteins secreted by the cancer cells, but only weakly with normal colon tissues. By assaying the reactivities with MLS102 of submaxillary mucins and synthetic oligosaccharide glycosides, the structure of an epitopic carbohydrate recongnized by MLS102 was determined as a cluster of NeuAc 2 6GalNAc attached to a certain peptide.
MLS102 antigens were isolated from cell lysates and spent media of LS180, and were compared with MLS103 antigens which were detected on cancerous and adjacent normal colon tissues. Affinity purified MLS102 antigen contained Ser, Thr and Pro as the most abundant amino acids, and the carbohydrate chains were composed mainly of O-glycosidically linked NeuAc 2 6GalNAc (56%) and GalNAc residues (25%). O-glycosidically linked oligosaccharides of MLS103 antigen were different in size from those of MLS102 antigen, and consisted of longer carbohydrate chains.
Another monoclonal antibody MSW113 generated using SW1111 as immunogen was shown to be directed mainly to mucin type oligosaccharide with sialyl-Le^a antigen. Reactivity of MSW113 to sialyl-Le^a was stronger than that of NS19-9, which is believed to be raised against the same determinant group. MSW113 binds to sialyl-Le^a-ol, LS-tetrasaccharide a, and disialyllacto-N-tetraose with higher affinities, compared to NS 19-9. These two antibodies could clearly be distinguished in that MSW113 bound to sialic acid but not fucose, whereas NS 19-9 bound to fucose but not to sialic acid-containig internal structures. MSW113 was found to be useful for detecting antigens in the bloodstream of patients, especially those with pancreas cancer.
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