title: Characterization of a unique glycoprotein antigen expressed on the surface of human neuroblastoma cells.
abstract: In order to develop a molecular probe to delineate chemical and biological characteristics of human neuroblastoma cells, a murine monoclonal antibody (Mab 5G3) was produced that is directed to a glycoprotein, preferentially expressed on the surface of such cells. This antibody is of IgG2a isotype, has an association constant of 8 X 10(9) M-1, and reacts preferentially with human neuroblastoma cell lines and fresh frozen tissue sections in enzyme-linked immunosorbent assay and immunoperoxidase assays, respectively. Minimal reactivity is observed with a variety of lymphoblastoid cell lines and normal fetal and adult tissues. Mab 5G3 specifically recognizes a neuroblastoma target glycoprotein antigen of 215 kDa that is derived from a 200-kDa precursor, as evident from pulse-chase biosynthetic studies. Treatment with tunicamycin revealed that both molecules contain N-asparagine-linked oligosaccharides; however, only the 215-kDa species is resistant to treatment with endo-beta-N-acetylglucosaminidase H and sensitive to neuraminidase, indicating that it contains trimmed and terminally sialylated oligosaccharides of the "complex" type. In contrast, the 200-kDa precursor is sensitive to endo-beta-N-acetylglucosaminidase H and resistant to neuraminidase treatment indicating that it contains high-mannose non-processed oligosaccharides. The 215-kDa molecule is sulfated, phosphorylated at serine residues, and expressed on the cell surface. A molecule of 200 kDa is detected by Mab 5G3 in spent culture medium of human neuroblastoma cells which is neither sulfated nor phosphorylated.
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000951:Antigens, Neoplasm / Q000276:immunology*; D000954:Antigens, Surface / Q000032:analysis / Q000276:immunology*; D002460:Cell Line; D004797:Enzyme-Linked Immunosorbent Assay; D006023:Glycoproteins / Q000096:biosynthesis / Q000276:immunology*; D006801:Humans; D007124:Immunoenzyme Techniques; D051379:Mice; D008807:Mice, Inbred BALB C; D009447:Neuroblastoma / Q000276:immunology*; D009844:Oligosaccharides / Q000032:analysis; D010766:Phosphorylation; D013431:Sulfates / Q000378:metabolism
chemical_list: D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm; D000954:Antigens, Surface; D006023:Glycoproteins; D009844:Oligosaccharides; D013431:Sulfates