Structural and biological aspects of blood group I and i antigens on glycolipids and glycoproteins.

I and i oligosaccharide sequences are carried on a multiplicity of glycoproteins and glycosphingolipids. They occur as accessible or as partially or totally masked antigens on the surface of diverse cell types and in certain secretions. Changes in their expression may occur during differentiation, development, cell cycle and oncogenesis. There is suggestive evidence that they may be coupled to receptor systems on lymphocyte membranes. Monoclonal anti-I and i antibodies hold promise as reagents in biological chemistry.