The adsorption behaviour of two commercial IgG-preparations onto a polystyrene latex surface

The adsorption behaviour of two commercial preparations of human IgG onto a polystyrene latex surface was studied. The adsorption isotherms obtained differed markedly; one preparation showed a plateau value of 0.4 microgram cm-2 which was reached at 0.1 g l-1, whereas the other preparation showed no plateau value within the concentration range studied (0.1-7.0 g l-1). Characterization by means of iso-electric focusing and HPLC also showed differences between the two preparations. No differences were observed when immuno-electrophoresis was carried out. These results stress the necessity for proper characterization of proteins used in adsorption studies.