To develope a new enzyme immune assay (ELISA) for detection of M2 antibody specific for primary biliary cirrhosis (PBC) by using a triple hybrid clone as antigen, which coexpresses the three immunodominant lipoyl domains of PDC-E2, BCOADC-E2 and OGDC-E2 from human sources.
In this study, a recombinant bovine BCOADC-E2 fusion protein has been expressed in insect cells using baculovirus expression system and analyzed anti-BCOADC-E2 reactivity in sera from patients with PBC or with IDCM.
The recombinant OGDC-E2 was judged to express the immunodominant epitope, because when sera from patients with PBC were preabsorbed with the recombinant fusion protein, such sera were depleted of reactivity against 48 kD OGDC-E2 when probed on beef heart mitochondria (BHM) but retained reactivity toward PDC-E2 and/or BCOADC-E2.