Expression of blood group I and i active carbohydrate sequences on cultured human and animal cell lines assessed by radioimmunoassays with monoclonal cold agglutinins.

Human monoclonal anti-I and anti-i antibodies, reactive with known carbohydrate sequences, have been used as reagents to quantitate (by radioimmunoassay) and visualize (by immunofluorescence) the expression of the various blood group I and i antigenic determinants in a variety of cultured cell lines commonly used in laboratory investigations. It has been shown that the antigens they recognize are widely distributed on the surface of human and animal cell lines, expressed in varying amounts in different cell lines and on individual cells within a given cell line. In two cell lines, a transformation-associated increase in the expression of I antigen was observed. Because of their precise specificity for defined carbohydrate chain domains, these autoantibodies have become valuable reagents in biological chemistry.