The association of the autoantigens of primary biliary cirrhosis with the mitochondrial H+-ATPase--a reassessment.

The claimed association between the M2 autoantigens of primary biliary cirrhosis (PBC) and the mitochondrial H+-ATPase has been re-examined in view of the recent reports that PBC autoantibodies react specifically with the lipoate acetyl transferases of 2-oxo acid dehydrogenases. Study of F0F1-ATPase purified from human and yeast mitochondria, and the comparison between immunoprecipitates obtained with antibodies against the H+-ATPase beta subunit and anti-M2 antibodies of PBC, established that the M2 antigens are not associated with the H+-ATPase complex. The M2 antigens did copurify with a crude bovine heart F1-ATPase preparation, but not with F1-ATPase from yeast, human heart or human liver.