Influence of bleomycin and pepleomycin on mitogen stimulations of human lymphocytes in vitro.

Bleomycin (BLM) and Pepleomycin (PEP), two antineoplastic drugs, strongly inhibited PHA-triggered DNA-synthesis of human lymphocytes when present during the culture period. Preincubation of lymphocytes with BLM or PEP for 3 days, however, only reduced the subsequent PHA-stimulations at very high drug concentrations. This differential sensitivity of resting and activated lymphocytes made it possible to inactivate subsets of mitogen or MLC reactive lymphocytes with a high grade of selectivity.