Effect of distamycin A on the primary and secondary immune response of mouse spleen cells in vitro against sheep erythrocytes.

The effect of distamycin A (DMC) on the primary and secondary immune response of mouse spleen cells, cultured in vitro in the presence of sheep erythrocytes as an antigen, was studied. It was found that the primary response was extremely sensitive to DMC during the first 24 hrs of culture and then gradually became more and more resistant to the immunosuppressive effect of the drug. Right from the start of culture, however, the secondary response was much more resistant than the primary one to the inhibitory action of DMC. These results could not be reproduced by treating the cultures with inhibitors of DNA-dependent DNA synthesis (such as cytosine arabinoside) or inhibitors of DNA-DEPENDENT RNA synthesis (such as actinomycin D).