[The occurrence of cross-reactive antigens in myocardial tissue and in streptococcus pyogenes. IV. Cytotoxic effect of lymphocytes sensitized in vivo to group A streptococci on primary cultures of heart muscle cells (author's transl)].

The cytotoxic effect of rat lymphocytes in vivo sensitized to group A streptococci, rat heart tissue or streptococcal M proteins was investigated in primary cultures of beating rat heart cells. Cytotoxicity was found in 75 to 82% of heart cell cultures in contact with lymphocytes sensitized to streptococcal whole cells or lysates and in 100% of those exposed to lymphocytes sensitized to rat heart tissue. Lymphocytes sensitized to M protein exert a cytopathic effect only in 8 and 12% cultures, respectively, and to a much more limited extent. Controls were affected in 6%. The cytotoxicity test seems to be useful to examine the presence of cross-reactive antigens within streptococcal vaccines.