Doxorubicin-induced alterations in cultured myocardial cells stimulate cytolytic T lymphocyte responses.

Doxorubicin treatment of cultured murine myocytes induces alterations capable of stimulating CD8+ cytolytic T lymphocyte (CTL) responses in vitro. Lymphocytes from normal BALB/cBy female mice were cultured for times varying from 2 to 10 days on syngeneic neonatal myocytes treated with doxorubicin, and surviving lymphocytes was assayed for cytotoxicity to drug-treated and untreated myocyte targets. Maximal cytolytic responses occurred on day 8. Activity to treated targets was twice that observed with untreated myocytes. Concentrations of the drug as low as 10(-8) mol/l (molar) for as little as 30 minutes initiated the necessary antigenic changes, although treatment with 10(2)-fold higher concentration for 4 to 6 hours appeared optimal. Cytotoxicity of the lymphocyte population could be eliminated by pretreatment of the sensitized effector cells with either anti-Thy 1.2 or anti-Lyt 2 monoclonal antibody and complement, while treatment with complement alone or anti-L3T4 monoclonal antibody and complement were ineffective. Myocardial cells were not the only tissue-derived targets susceptible to lysis by the drug-induced CTL. Lymphocytes stimulated on doxorubicin-treated myocytes demonstrated even better cytotoxicity to drug-treated neonatal kidney cells, but showed only minimal activity to neonatal liver or skin fibroblasts. Concentrations of doxorubicin per 10(6) cells was greatest for kidney cells followed by heart and liver cells. Skin fibroblasts incorporated the least amount of the drug. Therefore, there was a partial correlation between sensitivity of drug-treated targets to immune cytolysis and drug uptake.