Significance of anti carbonic anhydrase antibodes in rheumatic autoimmune diseases *
We have previously reported that autoantibodies against carbonic anhydrase (CA) exist in sera from patients with rheumatic autoimmune diseases (RAD). For further characterization of this autoantibody, linear autoepitopes on CA I and CA Ⅱ molecules were analyzed, CA I and CA Ⅱ peptides consisting of 12-16 mer amino acids were synthesized and coupled with bovine serum albumin (CA I：Pl-P21, CAⅡ：P1-P20). The reactivity of patient and healthy control sera to each peptide was detected by ELISA . Anti - CA I autoantibodies showed dominant reactivity to several peptides. Peptides 5 and 7 were common epitopes in healthy controls and RAD. Peptides 1 , 2 and 4 were also characteristic peptides in each desease；i. e. peptides 1 and 2 in systemic lupus erythematosus, peptide 4 in Sjogren's syndrome and peptide 1 in progressive systemic sclerosis. On the other hand, anti-CA Ⅱ autoantibodies commonly showed dominant reacivity to peptides 2 , 8 and 15 in RAD. However, the sera of healthy controls only reacted to peptide 20. Especially, noteworthy was the observation that peptide 8 was located on the active portion surrounding the zinc core. Therefore, anti-CA Ⅱ autoantibodis might possibly affect the enzyme activity in RAD. (Accepted on March 9 , 1998) Kawasaki Igakkaishi 23(4) : 241-249. 1997
