Expression,Purification and Preliminary Identification of Recombinant Human Complete IgG Antibody against HBsAg

Objective To express,purify and preliminarily identify recombinant human complete IgG antibody against HBsAg.Methods Co-transfect sf9 insect cells with recombinant plasmid pAC-HBs-Fc containing Fc fragment anti-HBsAg Fab antibody gene and the linear DNA of baculovirus for expression of recombinant human complete IgG antibody against HBsAg.The expressed product was analyzed for specificity by indirect ELISA using the microtiter plate coated with HBsAg,then purified by protein G affinity chromatography and identified by SDS-PAGE,Western blot and competitive ELISA.Results The expressed recombinant human complete IgG antibody was highly specific to HBsAg and reached a purity of 97.1% after purification.SDS-PAGE and Western blot proved the expressed product as human complete IgG antibody,of which the relative molecular masses of light and heavy chains were about 27 000 and about 55 000 respectively.The HBsAg expressed in CHO cells and plasma-derived HBsAg competitively inhibited the reaction of expressed recombinant human complete IgG antibody with HBsAg expressed in E.coli,with inhibition rates of 55.9% and 81.9% respectively.Conclusion Recombinant human complete IgG antibody against HBsAg was successfully expressed in baculovirus expression system.