Analysis of mitochondrial antigens reveals inner membrane succinate dehydrogenase flavoprotein subunit as autoantigen to antibodies in anti‐M7 sera

• Published in: Clinical and experimental immunology Vol. 128; no. 1; pp. 83 - 87
• Main Authors: CICEK, G., SCHILTZ, E., HESS, D., STAIGER, J., BRANDSCH, R.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 01.04.2002; Blackwell; Oxford University Press; Blackwell Science Inc
• Subjects: Animals; antimitochondrial antibodies; Autoantibodies - blood; Autoantibodies - immunology; Autoantigens - immunology; Biological and medical sciences; Blotting, Western; Cardiology. Vascular system; Cattle; Clinical Studies; Electron Transport Complex II; Electrophoresis, Gel, Two-Dimensional; Electrophoresis, Polyacrylamide Gel; Escherichia coli - enzymology; Flavins - chemistry; flavoprotein; Flavoproteins - chemistry; Fluorescence; General aspects; Heart; Humans; Immunopathology; Intracellular Membranes - enzymology; Medical sciences; Mitochondria - enzymology; mitochondrial antigen; Mitochondrial Proteins - immunology; Multienzyme Complexes - chemistry; Multienzyme Complexes - immunology; myocarditis; Myocarditis - immunology; Myocarditis. Cardiomyopathies; Oxidoreductases - chemistry; Oxidoreductases - immunology; Protein Subunits; Rats; succinate dehydrogenase; Succinate Dehydrogenase - chemistry; Succinate Dehydrogenase - immunology; Autoimmunity; Human; Immunopathology; Succinate dehydrogenase; Enzyme; Antibody; Pathogenesis; Cardiovascular disease; Serology; Flavoprotein; Myocardial disease; Antigen; Myocarditis; EC 1.3.99.1; Respiratory chain; Mitochondria; Autoantigen; Immunological investigation; Heart disease; Oxidoreductases
• ISSN: 0009-9104; 1365-2249
• DOI: 10.1046/j.1365-2249.2002.01816.x

SUMMARY The role of mitochondrial proteins as antigens to antibodies of anti‐M7 sera was analysed by flavin fluorescence, one‐ and two‐dimensional Western blots and blue native gel electrophoresis. Flavin fluorescence of succinate dehydrogenase (SucDH, complex II of the respiratory chain) of rat liver inner mitochondrial membranes correlated with the immunoreactivity of a representative anti‐M7 myocarditis serum. Antigens of isolated bovine heart mitochondria reacting with antibodies of myocarditis serum on two‐dimensional Western blots were identified by MALDI‐TOF and NanoESI mass spectrometry as myosin heavy chain β and as dihydrolipoamide dehydrogenase of the mitochondrial 2‐oxoacid dehydrogenase complexes. The SucDH‐flavoprotein was not resolved as a discrete protein spot on two‐dimensional polyacrylamide gels. However, separation of the rat liver inner mitochondrial membrane complexes by blue native gel electrophoresis followed by Western blotting, and Western blots of purified Escherichia coli SucDH complex revealed that anti‐M7 sera contained antibodies directed against the SucDH‐flavoprotein subunit.