In vitro study of the modification by bleomycin of thymidine phosphorylation activity in lectin-stimulated normal human lymphocytes.

We have investigated the effect of bleomycin (BLM) on thymidine phosphorylation in lectin-stimulated normal human lymphocytes. BLM reduces thymidine phosphorylation by decreasing the activity of thymidine kinase (TK). Accordingly, polyacrylamide gel electrophoresis (PAGE) of extracts of cells incubated for 48, 72 and 96 h showed here that this activity dropped 48, 65 and 67% respectively. The electrophoretic profiles of TK activity were similar but different in amplitude. These effects of the BLM were confirmed firstly by direct measurement of TK activity, secondly by amount of 3H-thymidine incorporation in the cultures before cell lysis. Both the measurement of TK activity and 3H-thymidine incorporation were correlated.