title: Ganglioside GM2 as a human tumor antigen (OFA-I-1).
abstract: A monospecific antibody produced in vitro by a B-lymphoblastoid cell line transformed with Epstein-Barr virus has been shown to recognize a membrane antigen (OFA-I-1) on human tumors and fetal brain. This study identifies the chemical nature of OFA-I-1. The glycolipid fraction of antigen-rich spent medium of an OFA-I-1-positive melanoma cell line, M14, was extracted by chloroform/methanol/water, 4:8:3 (vol/vol), and was separated into fractions of neutral glycolipids and gangliosides by DEAE-Sephadex followed by base treatment and Bio-sil A column elution. OFA-I-1 antigens were found exclusively in the ganglioside fraction when assayed with monospecific anti-OFA-I-1 by an immune adherence inhibition test. The results obtained from thin-layer chromatography of the antigenic M14 ganglioside and sequential glycosidase digestion suggested that the antigen was a ganglioside GM2, GalNAc beta 1 leads to 4(NeuAc alpha 2 leads to 3)Gal beta 1 leads to 4Glc leads to Cer. These results were further supported by testing various authentic gangliosides and neutral glycolipids for OFA-I-1 antigenicity. Only GM2 showed positive reactivity.
mesh_terms: D000328:Adult; D000951:Antigens, Neoplasm / Q000276:immunology*; D001921:Brain / Q000276:immunology; D002241:Carbohydrates / Q000032:analysis; D002460:Cell Line; D000939:Epitopes / Q000032:analysis; D005260:Female; D005333:Fetus; D005678:G(M2) Ganglioside / Q000276:immunology*; D005732:Gangliosides / Q000276:immunology* / Q000302:isolation & purification; D006017:Glycolipids / Q000302:isolation & purification; D006801:Humans; D008099:Liver / Q000276:immunology; D008545:Melanoma / Q000276:immunology*; D011247:Pregnancy
chemical_list: D000951:Antigens, Neoplasm; D002241:Carbohydrates; D000939:Epitopes; D005732:Gangliosides; D006017:Glycolipids; C031192:oncofetal antigens; D005678:G(M2) Ganglioside