title: Leishmania donovani: surface membrane acid phosphatase blocks neutrophil oxidative metabolite production.
abstract: We show that a purified preparation of the prominent tartrate-resistant acid phosphatase (E.C.3.1.3.2), isolated from the external surface of the intracellular parasite Leishmania donovani (promastigote form), inhibits toxic oxidative metabolite production of neutrophils. Preincubation of a neutrophil suspension (2.5 X 10(6) cells/ml) for 15 min at 37 C with 250 units (1 unit equals 1 nmole of 4-methylumbelliferyl phosphate cleaved per hr at pH 5.5) of the acid phosphatase in Krebs-Ringer phosphate buffer (pH 7.4) decreased O2 consumption, O2- production, and H2O2 production of N-formyl-methionyl-leucyl-phenylalanine (fMet-Leu-Phe)-stimulated neutrophils to 15-25% of control values. The acid phosphatase also affected concanavalin A-stimulated O2-production by neutrophils, but had no effect on the rate of phorbol myristic acetate-stimulated O2- production, chemotactic peptide binding, degranulation, or membrane depolarization. Addition of an acid phosphatase inhibitor (Complex E; (NH4)6[P2Mo18O62] X 9H2O) to suspensions of opsonized promastigotes and neutrophils resulted in a threefold or greater enhancement of O2- production. These results suggest a possible pathophysiologic role for the acid phosphatase of L. donovani promastigotes.
mesh_terms: D000135:Acid Phosphatase / Q000378:metabolism*; D000818:Animals; D002462:Cell Membrane / Q000201:enzymology; D002630:Chemotactic Factors / Q000494:pharmacology; D004705:Endocytosis; D005966:Glucuronidase / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism; D007893:Leishmania donovani / Q000201:enzymology*; D008247:Lysosomes / Q000378:metabolism; D008564:Membrane Potentials; D009113:Muramidase / Q000378:metabolism; D009504:Neutrophils / Q000378:metabolism* / Q000469:parasitology / Q000502:physiology; D010101:Oxygen Consumption; D013481:Superoxides / Q000378:metabolism
chemical_list: D002630:Chemotactic Factors; D013481:Superoxides; D006861:Hydrogen Peroxide; D000135:Acid Phosphatase; D009113:Muramidase; D005966:Glucuronidase