title: Extracellular nucleotide catabolism in human B and T lymphocytes. The source of adenosine production.
abstract: Extracellular nucleotide degradation was studied in intact human B and T lymphocyte subpopulations and in lymphoblastoid cell lines. Cells of B lymphocyte lineage showed high nucleotide degrading activity, whereas T lymphocytes were unable to degrade extracellular nucleotides. The external surface of B cells contained active sites of ecto-triphosphonucleotidase (ecto-ATPase), ecto-diphosphonucleotidase (ecto-ADPase), and ecto-monophosphonucleotidase (ecto-AMPase). The expression of all three ectoenzyme activities seemed closely associated with B cell development. ATPase and ADPase activities increase continuously during B cell maturation, ecto-AMPase activity, on the other hand, reaches maximal activity in late pre-B cells. These results combined with our previous studies of intracellular ATP catabolism (Barankiewicz, J., and Cohen, A. (1984) J. Biol. Chem. 259, 15178-15181) provide evidence that extracellular ATP catabolism may represent exclusive source for adenosine in lymphocytes. It is suggested that adenosine may serve as a means of communication between B and T cells in lymphoid organs, B lymphocytes being the sole producers of adenosine and T lymphocytes being the recipients of this signal.
authors.affiliation: Division of Immunology and Rheumatology, Hospital for Sick Children, Toronto, Ontario, Canada.
authors.forename: J
authors.initials: J
authors.lastname: Barankiewicz
authors.forename: H M
authors.initials: HM
authors.lastname: Dosch
authors.forename: A
authors.initials: A
authors.lastname: Cohen
mesh_terms: D000241:Adenosine / Q000378:metabolism*; D000244:Adenosine Diphosphate / Q000378:metabolism; D000249:Adenosine Monophosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism*; D001402:B-Lymphocytes / Q000378:metabolism*; D002250:Carbon Radioisotopes; D002460:Cell Line; D002478:Cells, Cultured; D006801:Humans; D019271:Hypoxanthine; D007042:Hypoxanthines / Q000378:metabolism; D007288:Inosine / Q000378:metabolism; D007700:Kinetics; D009711:Nucleotides / Q000378:metabolism*; D014066:Palatine Tonsil; D013601:T-Lymphocytes / Q000378:metabolism*; D014316:Tritium
chemical_list: D002250:Carbon Radioisotopes; D007042:Hypoxanthines; D009711:Nucleotides; D014316:Tritium; D019271:Hypoxanthine; D000249:Adenosine Monophosphate; D007288:Inosine; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D000241:Adenosine