[Monoclonal antibodies cross-reacting with fibroblasts of interstitial connective tissue of the myocardium and cell wall protein antigens of group A Streptococcus].

Monoclonal antibodies (MCA) B6/5 and C5/3 were obtained after immunization of BALB/c mice with the protein non-type-specific antigens (NTSA) of streptococcal group A cell wall. MCA B6/5 in the indirect immunofluorescence react with human and animal interstitial connective tissue (ICT) of the myocardium and human fibroblast culture cells. MCA C5/3 react with the bands of muscle fibers of the myocardium. MCA B6/5 and C5/3 are autoantibodies. It was revealed that these MCA are directed to two streptococcal cross-reacting antigens (CRA). Production of B6/5 and C5/3, apparently, does not depend on the possibility of some streptococcal antigens to bind fibrinogen. Bound immunoglobulins were not revealed in the ICT and in the muscle fibres by the cultivation of the C5/3 monoclone. Firstly it was stated that, MCA B6/5, reacting with fibroblasts and with streptococcal CRA, are capable to fix in the ICT of myocardium, what is typical for the phenomenon described in rheumatic fever.