Dipeptidylpeptidase IV in human leukemic B- and T-cells.
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.
Institute of Biological and Medical Chemistry, Russian Academy of Medical Sciences, Moscow.
V S
VS
Bylinkina
L A
LA
Lokshina
R S
RS
Samojlova
O N
ON
Lubkova
T A
TA
Gureeva
N V
NV
Golubeva
D000943:Antigens, Differentiation; D001402:B-Lymphocytes / Q000201:enzymology* / Q000276:immunology; D002454:Cell Differentiation; D018819:Dipeptidyl Peptidase 4; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases / Q000378:metabolism*; D006801:Humans; D007938:Leukemia / Q000201:enzymology* / Q000276:immunology; D008213:Lymphocyte Activation; D008232:Lymphoproliferative Disorders / Q000201:enzymology / Q000276:immunology; D010641:Phenotype; D013601:T-Lymphocytes / Q000201:enzymology* / Q000276:immunology
D000943:Antigens, Differentiation; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases; D018819:Dipeptidyl Peptidase 4