title: Mapping of two new epitopes on the apomucin encoded by MUC5AC gene: expression in normal GI tract and colon tumors.
abstract: Three hybridomas secreting monoclonal antibodies (MAbs) against human (62M MAb) or rat (463M and 589M MAbs) gastric mucins were isolated. These MAbs immunoreacted against a human recombinant protein encoded by the 3' region of the MUC5AC gene. We have mapped 2 new gastric mucin epitopes and the M1-f epitope previously characterized by the 19/21M1 MAbs on MUC5AC-encoded apomucin. The M1-f, 463/589M and 62M epitopes are located in the MUC11p15/von Willebrand factor (vWF)-A3uD4 domain, in the D4-(vWF)-like domain and in the C- and CK-vWF-like domains of MUC5AC, respectively. The 463/589M and 62M MAbs stained the surface epithelium of human gastric mucosae, but not the normal colon mucosae (except 463/589M MAbs, which immunoreacted with 5 of 49 cases). All hyperplastic polyps are stained strongly with the 463/589M MAbs and faintly with the 62M MAb. In addition, 463/589M epitope was detected in 64% of the adenomas and in 93% of the mucosae adjacent to adenocarcinomas; in contrast, only 9% of the adenomas and 29% of the mucosae adjacent to adenocarcinomas expressed the 62M epitope. The expression pattern of the 463/589M epitope in colonic carcinogenesis is different from that of the 19/21M1 epitope, although the 2 epitopes are encoded by MUC5AC gene.
authors: INSERM U-482, Hôpital Saint-Antoine, Paris, France.
authors: Séverine
authors: S
authors: Nollet
authors: Marie-Elisabeth
authors: ME
authors: Forgue-Lafitte
authors: Paul
authors: P
authors: Kirkham
authors: Jacques
authors: J
authors: Bara
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000378:metabolism; D003110:Colonic Neoplasms / Q000378:metabolism*; D018076:DNA, Complementary / Q000378:metabolism; D004064:Digestive System / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D000939:Epitopes / Q000737:chemistry; D005752:Gastric Mucins / Q000737:chemistry*; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D055271:Mucin 5AC; D009077:Mucins / Q000737:chemistry*; D009092:Mucous Membrane / Q000378:metabolism; D010449:Peptide Mapping; D010455:Peptides / Q000737:chemistry; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D051381:Rats; D013997:Time Factors; D014407:Tumor Cells, Cultured
chemical_list: D000911:Antibodies, Monoclonal; D018076:DNA, Complementary; D000939:Epitopes; D005752:Gastric Mucins; C524678:MUC5AC protein, human; C524679:Muc5ac protein, mouse; C524680:Muc5ac protein, rat; D055271:Mucin 5AC; D009077:Mucins; D010455:Peptides; C053366:apomucin