UP-REGULATION OF TELOMERASE ACTIVITY IN HUMAN-LYMPHOCYTES

We detected telomerase activity in human lymphocytes obtained from nor mal donors. Telomerase was up-regulated within 24 h when peripheral bl ood mononuclear cells were cultured in the presence of phytohemaggluti nin. The activity increased gradually over 72 h, then remained stable for 96 h. During this period, cell number and the length of telomeric DNA remained constant. Anti-CD3 monoclonal antibody and Pansolbin also induced telomerase activity. These results demonstrate that telomeras e is regulated during lymphocyte activation as cells progress from G(0 ) to S phase. This system is useful for the study of telomerase during carcinogenesis, and in the testing of telomerase-inhibitory drugs.