ANTIBODIES IN THE SERA OF ACUTE RHEUMATIC-FEVER PATIENTS BIND TO HUMAN CARDIAC TROPOMYOSIN

Previous work from this laboratory has demonstrated the occurrence of heart reactive antibodies (HRA) in the sera of acute rheumatic fever ( ARF) patients which bound primarily to the sarcolemmal sheath of cardi ac myofibres. While many investigators have reported the presence of a ntibodies to myosin in the sera of ARF patients, the question of wheth er these sera also contain antibodies to other cytoskeletal proteins h as not been addressed; In this study, crude human sarcolemmal sheaths were extracted with 3 M KCl and partially purified using a DEAE cellul ose column and a step gradient of NaCl. Maximum reactivity with ARF se ra was seen with a protein fraction eluted with 0.3 M NaCl. Using FPLC , a single polypeptide of 38 kDa reacted in ELISA preferentially with ARF sera when compared to sera from patients with uncomplicated strept ococcal infections and acute post-streptococcal glomerulonephritis (AP SGN). A comparison of the N-terminal sequence of the purified protein and competitive inhibition assays indicated that the reactive sarcolem mal antigen was human cardiac tropomyosin. (C) 1997 Academic Press Lim ited.