Detection of glycophorin A-like glycoproteins on the surface of cultured human cells.

1. In previous studies we have isolated and characterized mucin-type glycopeptides from mouse and human melanoma cells. 2. These glycopeptides have clusters of oligosaccharides of the type (NeuNAc)0-2----[Gal----GalNAc] linked to serine and or threonine suggesting an apparent similarity to glycophorin. 3. We now report the interaction of polyclonal anti-glycophorin antibodies with various cultured cells. Antisera to highly purified glycophorin A were raised in rabbits. 4. Human melanoma cells (HM7), human breast cells (HBL-100) and two lines of human breast cancer cells (MCF-7 and MDA-MB-231) showed medium to very strong cell surface fluorescence pattern after staining with rabbit anti-glycophorin F(ab')2 and FITC-conjugated goat anti-rabbit F(ab')2. 5. Immunodiffusion, immunoelectrophoresis and affinity chromatography on anti-glycophorin IgG-Sepharose 4B of detergent extracts of metabolically labeled cultured cells gave further evidence for the presence of glycophorin-like components in these cells. 6. Glycoproteins of MCF-7 cells interacting with anti-glycophorin antibodies were affinity purified and partially characterized.