[Proteolytic enzymes in human lymphocytic leukemia cells. I. Activity of dipeptidylaminopeptidase IV, plasminogen activator and cathepsins B and L in cells with different immunologic phenotype].

Immunological and biochemical study of lymphoid cells obtained from 20 patients with various forms of lymphoproliferative disorders has been carried out. It was found that different phenotypes of lymphoid cells at various stages of differentiation have different activity levels of dipeptidyl aminopeptidase IV (DAP IV), plasminogen activator (urokinase type) and cathepsins B + L. The highest proteinase activity values were found in the lysates of just those leukemic T-cells whose phenotypes corresponded to the initial stages of thymic differentiation or to activated T-cells. The 10 times lowered activity was found in the cell phenotypes of mature T-helpers and T-suppressors, and the activity of the both was at virtually the same level. In lymphoid cells of the B-lineage (from pre-B to mature B-lymphocytes) the proteinase activities did not differ essentially: they were 2 to 3 times lower than in the lymphoid progenitors. It was suggested that the regulated activity changes in some proteinases occur during differentiation along the T- or B-pathways. It is likely that the increases in DAP IV and cathepsins B + L activities are associated with the activation of mature lymphoid T- and B-cells. No direct correlation was found between the activity of either proteinase and the expression of any of the surface markers under study.