title: Ectoenzymes on the surface of cells from human lymphoblastoid lines: 5'-nucleotidase and phosphatase.
abstract: Activities of the ecto-enzymes 5'-nucleotidase (5'-N) and phosphatase were determined on the surface of intact cells from 15 different established lines of human B- and T-lymphoblasts. Whereas all the lines express phosphatase, 10 of the lines were negative for 5'-N. 5'-N-negative cell lines are found among B as well as T cells, and they do not carry cryptic enzyme activity. In a 5'-N-positive line activity of this enzyme is correlated with growth showing a peak during the logarithmic phase. On the other hand, inhibition of 5'-N does not change the growth curve of this line. Neuraminidase treatment of the cell surface brings about an increase in phosphatase but not in 5'-N activity. 5'-N of two B-cell lines of human peripheral blood lymphocytes shows complete crossreactivity with an antiserum obtained against human placental 5'-N. However, the enzyme of one lymphoma line with B-cell properties (EHR-A-Ramos) does not cross-react with this serum. The results are discussed with respect to suitability of these lymphoblast lines as model systems for the study of immunodeficiencies.
mesh_terms: D001402:B-Lymphocytes / Q000201:enzymology; D002460:Cell Line; D003429:Cross Reactions; D005260:Female; D006801:Humans; D007106:Immune Sera; D008214:Lymphocytes / Q000201:enzymology*; D009439:Neuraminidase / Q000494:pharmacology; D009708:Nucleotidases / Q000032:analysis*; D010744:Phosphoric Monoester Hydrolases / Q000032:analysis*; D010920:Placenta; D011247:Pregnancy; D013601:T-Lymphocytes / Q000201:enzymology
chemical_list: D007106:Immune Sera; D009708:Nucleotidases; D010744:Phosphoric Monoester Hydrolases; D009439:Neuraminidase