Dipeptidylpeptidase IV in human leukemic B- and T-cells
Bylinkina, V.S.; Lokshina, L.A.; Samojlova, R.S.; Lubkova, O.N.; Gureeva, T.A.; Golubeva, N.V.
Biochemistry International 28(1): 31-39
1992
ISSN/ISBN: 0158-5231 PMID: 1359891 Document Number: 395592
Dipeptidylpeptidase IV (DPP-IV) activity in lymphoid cells of patients with various lymphoproliferative diseases has been assayed. The enzyme activity was detected in lysates of all leukemic T- and B-cells studied. High DPP-IV activity levels (5-7 fold higher than those in mature Th and Ts) were found in T-cells with phenotypes corresponding either to the early thymic stages of maturation, or to activated T-lymphocytes, or to some atypic T-cells. In most leukemic B-cells with phenotypes of mature and late B-lymphocytes, the DPP-IV activity was lower than in mature T-cells; however, in some B-cells carrying the activation markers CD 25 and CD 30 the activity was rather high. High DPP-IV activity was seen in the majority of leukemic B-cells expressing CD 25 (87%) and CD 11C (82%) antigens. Experiments with intact cells have shown that DPP-IV is present in the plasma membrane of leukemic B- and T-cells studied. Thus DPP-IV cannot be considered as a marker of activated T-cells alone because a significant DPP-IV activity was also detected in a number of activated leukemic B-cells and in early T-cells.