EXPRESSION OF HUMAN RECOMBINANT BETA(2)-GLYCOPROTEIN-I WITH ANTICARDIOLIPIN ANTIBODY COFACTOR ACTIVITY

To enable the synthesis of beta2-glycoprotein I mutants we have establ ished a stable Chinese hamster ovary cell line that expresses human be ta2-glycoprotein I up to 2.9 mug/10(6) cells/day. Recombinant beta2-gl ycoprotein I is identical to the purified native protein with respect to cofactor activity revealed in a modified anti-cardiolipin ELISA. Au toimmune type anti-cardiolipin antibody requires recombinant beta2-gly coprotein I in a dose-dependent manner to bind cardiolipin whilst bind ing of infectious type antibody is inhibited. The purified recombinant beta2-glycoprotein I in serum free medium exists as two oligosacchari de species which upon deglycosylation have identical apparent molecula r weight to the deglycosylated native protein.