title: Natural killer cells lack ecto-5'-nucleotidase.
abstract: Ecto-5'-nucleotidase (ecto-5'-NUC, EC 3.1.3.5., CD73) is a plasma membrane enzyme, which catalyzes the hydrolytic dephosphorylation of purine nucleotides to the corresponding nucleosides so that they can pass through the plasma membrane. The distribution of ecto-5'-NUC is heterogeneous, but all blood mononuclear cell (BMC) subpopulations investigated until now have had ecto-5'-NUC activity. Purified natural killer (NK) cells were prepared by fluorescence-activated cell sorting of CD16-positive cells (purity 94%). In purified NK cells the ecto-5'-NUC activity was less than 1 U/10(6) as estimated by a radioisotope method. Using a cytochemical assay, the proportion of cells with activity was less than 1%. The most likely explanation is that NK cells have no ecto-5'-NUC activity and that the very small ecto-5'-NUC activity observed in this study was caused by contaminating non-NK cells. NK cells thus constitute the only BMC subset known without ecto-5'-NUC activity.
authors.affiliation: Department of Infectious Diseases M, Rigshospitalet, University Hospital, Copenhagen, Denmark.
authors.forename: L D
authors.initials: LD
authors.lastname: Christensen
authors.forename: V
authors.initials: V
authors.lastname: Andersen
mesh_terms: D015720:5'-Nucleotidase / Q000032:analysis*; D000328:Adult; D000943:Antigens, Differentiation / Q000032:analysis; D002478:Cells, Cultured; D005434:Flow Cytometry; D006801:Humans; D007694:Killer Cells, Natural / Q000201:enzymology*; D008875:Middle Aged; D011961:Receptors, Fc / Q000032:analysis; D017452:Receptors, IgG
chemical_list: D000943:Antigens, Differentiation; D011961:Receptors, Fc; D017452:Receptors, IgG; D015720:5'-Nucleotidase