Antibodies to E1 and E2/Protein X components of pyruvate dehydrogenase complex in sera of patients with primary biliary cirrhosis.
OBJECTIVE
Using purified E1 component of pyruvate dehydrogenase complex (PDC) from bovine heart, we measured the levels of anti-E1 antibodies in PBC sera using ELISA and determined the degree of inhibition that these antibodies exerted on E1 enzyme activity. We also estimated levels of anti-E2/Protein X (Pro-X) antibodies in PBC sera using purified E2 and Pro-X of PDC which were copurified with E1.


CONCLUSIONS
Anti-E1 antibodies were detected in 87.5% (35/40) of PBC sera. Some of these sera inhibited E1 enzyme activity but inhibition did not correlate with levels of anti-E1 antibodies. A high positive correlation (r = 0.918) was found between levels of anti-E1 and anti-E2/Pro-X antibodies, suggesting that anti-PDC antibody production was stimulated by PDC itself. Levels of IgG class anti-E2/Pro-X antibodies were significantly higher in sera of symptomatic PBC patients than in those of asymptomatic PBC patients. It was also found that patients who were positive for only IgM class anti-E2/Pro-X antibodies had early-stage PBC.
Kuroda
M
M
Department of Internal Medicine II, Fukushima Medical College, Japan.
Morito
T
T
Takagi
T
T
Ohira
H
H
Kokubun
M
M
Kojima
T
T
Ono
K
K
Kochi
H
H
Kasukawa
R
R
D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000032:analysis; D001323:Autoantibodies / Q000032:analysis*; D015415:Biomarkers / Q000097:blood; D002417:Cattle; D051047:Dihydrolipoyllysine-Residue Acetyltransferase; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D015151:Immunoblotting; D007074:Immunoglobulin G / Q000032:analysis; D008105:Liver Cirrhosis, Biliary / Q000201:enzymology / Q000276:immunology*; D010455:Peptides / Q000276:immunology* / Q000378:metabolism; D030481:Pyruvate Dehydrogenase (Lipoamide); D011768:Pyruvate Dehydrogenase Complex / Q000276:immunology* / Q000378:metabolism
D000888:Antibodies, Anti-Idiotypic; D001323:Autoantibodies; D015415:Biomarkers; D007074:Immunoglobulin G; C045867:PDHX protein, human; D010455:Peptides; D011768:Pyruvate Dehydrogenase Complex; C489061:pyruvate dehydrogenase complex component X, Bos taurus; D030481:Pyruvate Dehydrogenase (Lipoamide); D051047:Dihydrolipoyllysine-Residue Acetyltransferase