Experimentally-induced autoimmune myocarditis: production of heart myosin-specific autoantibodies within the inflammatory infiltrate.

ABSTRACT

Immunization with cardiac myosin in complete Freund's adjuvant (CFA) induces severe autoimmune myocarditis in A H-2 congenic mouse strains. The disease shares a variety of characteristics with Coxsackie-virus B3 (CB3)-induced myocarditis and is strongly associated with high-titered autoantibodies to cardiac myosin. Using the spot ELISA-technique, we demonstrate here that in cardiac myosin-immunized mice myosin autoantibodies were not only produced within the spleen, but also at the site of the autoimmune attack, i.e., within the inflammatory heart infiltrate. At the level of single plasma cells we further showed that a substantial part of the myosin autoantibodies was specific for the cardiac myosin isoform, thereby supporting previous serologic data. The finding that cells of the inflammatory heart infiltrate significantly contribute to autoantibody production might explain why the occurrence of high-titered myosin autoantibodies is restricted to mice which develop the disease.