URIDINE KINASE-ACTIVITIES IN NORMAL AND NEOPLASTIC LYMPHOID-CELLS

Abstract

Adult (l) and embryonic (ll) forms of uridine kinase [EC27.1.48] were identified in the transplantable EL-4 leukemia of C57BL/6 mice and in the P815Y mastocytoma of DBA/2 mice. Only species l is found in primary tumor cells of lymphoid origin (virus-induced feline lymphosarcoma, human acute and chronic lymphocytic leukemia) and normal calf thymocytes and porcine peripheral blood lymphocytes species l was induced 4-fold on stimulation of normal blood lymphocytes with phytohemagglutinin. The level of uridine kinase activity in the feline lymphosarcoma of thymus dependent lymphocytes origin and childhood lymphocytic leukemia of possible thymus dependent lymphocyte or null cell origin was similar to the induced level in phytohemagglutinin stimulated normal lymphocytes, i.e., thymus dependent lymphocytes. Lymphocytes of a patient with chronic lymphocytic leukemia of thymus-independent lymphocyte origin had a level of uridine kinase activity comparable to that of unstimulated normal lymphocytes or thymocytes. The uridine kinase activity in the EL-4 tumor cells was repressed by acute treatment of the mice with 5-azacytidine.