Recombinant domain v of β₂-glycoprotein i inhibits the formation of a 7-ketocholesteryl-9-carboxynonanoate and β₂- glycoprotein i complex

Our prior study has been reported the formation of the oxidized low-density lipoprotein (oxLDL)/β2-glycoproteinI (β2-GPI)/autoantibody complex facilitated the antiphospholipid syndrome (APS) process. The domain V of β2-GPI binds to the negatively charged molecules, e.g. 7-ketochoresteryl-9- caboxynonanoate (oxLig-1) derived from the oxLDL and mediates the interaction between oxLDL and β2-GPI. In the present study, the oxLig-1/β2-GPI/ anti-β2-GPI Ab (WB-CAL-1) model was established. The recombinant domain V of β2-GPI (rβ2-GPI DV) expressed in Escherichia coli competitively inhibits the interaction between β2-GPI and oxLig-1 in the enzyme-linked immunoassay. Moreover, the rβ2-GPI DV significantly inhibits the formation of the oxLig-1/β2-GPI/autoantibody complex in an APS patient. The present work suggests a novel possibility that rβ2-GPI DV could be used to inhibit the formation of oxLDL/β2-GPI/autoantibody complex, and give us a hint for the development of new therapeutic strategies to prevent the APS process.