Suppression of myosin-induced and adoptively transferred myocarditis by prior treatment with complete Freund's adjuvant

Background We evaluated the effect of pretreatment with complete Freund's adjuvant (CFA) on experimentally induced myocarditis concomitant with the assessment of antigen-specific properties of disease-triggering lymphocytes. Methods and results Rats pretreated with CFA a week prior to myosin immunization developed a significantly attenuated myocardial inflammation as compared to control-treated animals. Furthermore, prior administration of CFA virtually abolished histological evidence of myocarditis induced by transfer of antimyosin lymphocytes. CFA administered subcutaneously prior to myosin immunization resulted in a significant reduction in lymph node cell reactivity to myosin. Assessment of cultured medium from lymphocytes obtained from CFA-pretreated myosin-immunized rats revealed reduced levels of interferon gamma but an increased production of IL-10, suggesting an induction of a Thl to Th2 switch. Conclusions Thus, CFA treatment suppressed both myosin-induced as well as adoptively transferred myocarditis concomitant with induction of antigen-specific unresponsiveness to myosin and skewing of the immune response in favor of a Th2-dominated profile.