IMMUNOPURIFICATION OF HUMAN BETA(2)-GLYCOPROTEIN-I WITH A MONOCLONAL-ANTIBODY SELECTED FOR ITS BINDING-KINETICS USING SURFACE-PLASMON RESONANCE BIOSENSOR

The beta(2)-glycoprotein I (beta(2)GPI)-binding properties of five mur ine monoclonal antibodies immobilized as capture antibodies were studi ed using surface plasmon resonance detection. The monoclonal antibody with the fastest dissociation kinetics (6F3) was selected for the deve lopment of an immunoaffinity chromatography procedure, assuming that i ts behaviour would be similar in both systems since the covalent coupl ing chemistries involved amino groups in both cases. Under our experim ental conditions of a fast one-step procedure, beta(2)GPI was purified to homogeneity from human plasma with a yield of about 50%. beta(2)GP I was eluted under fairly mild conditions, either at low pH or at high pH. The immunoadsorbent was used five times without any apparent loss of binding capacity. The immunopurified protein showed similar bindin g to cardiolipin-coated polystyrene wells as beta(2)GPI purified by co nventional methods. However, differences in the pattern of immunoreact ivity in relation to the purification procedure were observed by surfa ce plasmon resonance using the monoclonal antibody with the highest as sociation kinetics (9G1) immobilized on the sensor surface. (C) 1998 E lsevier Science B.V.