Antibodies to large glycopeptides in sera from patients with ovarian germ cell tumours

Antibodies reactive with a murine teratocarcinoma cell line (F9) were detected by immunofluorescence staining in sera from patients bearing ovarian germ cell tumour. Immunochemical studies revealed that antibodies binding to the cell surface of F9 cells react with large glycopeptides which are known to be components of F9 antigens defined by murine anti-F9 antibodies. In addition, treatment of F9 cells with retinoic acid, which induces differentiation of embryonal carcinoma cells, distinctly reduced both the ability of these antibodies to stain F9 cells and the biosynthesis of large glycopeptides by the cells. These findings indicate that the large glycopeptides precipitable by the patients' antibodies are differentiation associated antigens on characteristic embryonic cells.