Effect of doxycycline on immune response in mice

The effect of doxycycline on immune response has been studied in mice, cell-mediated immunity being evaluated with the split heart allograft technique. Survival duration of heart transplants in animals treated with 2.5 mg of doxycycline per kg per day from the day of transplantation until rejection was slightly but significantly longer than in untreated animals, 18.8 days (P less than 0.05) as compared with 14.5 days. In doxycycline-treated animals, both agglutinating and hemolytic antibody response to sheep erythrocytes was slightly but significantly decreased, though there was no inhibition of splenic production of antibodies to sheep erythrocytes (as measured by the number of plaques of hemolysis detected). The results show the immune response in mice to be only moderately inhibited by doxycycline. The relevance of experiments in mice is also discussed.