Development of an enzyme immune assay for detecting M2 autoantibodies specific for primary biliary cirrhosis.

OBJECTIVE

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.

METHODS

After expressing autoantigens of PBC in prokaryote by constructing recombinant expressive plasmid successfully, the fusion protein was purified by affinity chromatography. The sera of 17 PBC patients were examined. As controls, the sera of 167 non-PBC patients and the sera of 1225 normal controls aged under 28 were examined.

RESULTS

None of the sera from the non-PBC patients or the normal controls was positive for anti-M2 shown by the new ELISA. However, the positivity rate for anti-M2 in the PBC patients was 100% (17/17), as shown by the new ELISA.

CONCLUSION

The detection system with a good sensitivity and specificity may be used as a powerful method for the diagnosis of PBC.