The Effects of Polyanions on NBT Reduction Hexose Monophosphate Shunt Activity, and Ultrastructure of Polymorphonuclear Leukocytes

Abstract

Heparin causes enhanced nitroblue tetrazolium (NBT) reduction by polymorphonuclear leukocytes (PMN's). To determine the mechanism of this stimulation, samples of 1 to 3 x 10(7) PMN's were incubated with various concentrations of heparin, chondroitin sulfate A (CSA), and chondroitin sulfate B (CSB), with and without NBT. The effect of the polyanions (PA) on PMN hexose monophosphate shunt (HMPS) activity was determined by the production of 14CO2 from glucose-1-14C by the leukocytes. NBT reduction was evaluated histochemically and spectrophotometrically at 515 mmu. Samples of PMN's in heparin and heparin-NBT mixtures were examined by electron microscopy after various incubation periods. Increased NBT reductions by PMN's was found when leukocytes were incubated with heparin, CSA, and CSB, but these compounds had no effect on the HMPS activity of PMN's unless NBT was added. Electron microscopy of samples that contained heparin-NBT revealed an insoluble complex that was phagocytosed by the leukocytes. The stimulation of PMN oxidative metabolism and NBT reduction that follows incubation with PA-NBT appears to be directly related to ingestion of this particulate complex by the leukocytes.

Neutrophil function in some skin diseases using zymosan as a stimulus in the nitro-blue tetrazolium test

“…NBT can form aggregates with heparin and fibrinogen in plasma and these can be phagocytosed leading to reduction (Segal & Levi, 1973). Czarnetzki et aL (1975) demonstrated that the degree of NBT reduction depends on the heparin concentration in the system but we took particular care to keep this at 20 /ig per ml in all these experiments. It may be that in addition to C5a fragments and heparin fibrinogen complexes, the extra stimulation provided by zymosan is due either to its particle size or the possibility that it forms aggregates with heparin and fibrinogen.…”

Nitroblue-tetrazolium test for the functional evaluation of phagocytic cells: A critical analysis of the methodology

“…Already in 1941 it had been stressed by KUHN and JERCHEL [6] that tetrazolium salts are suitable to demonstrate the capacity for reduction in biological systems. Concerning the NBT reduction by phagocytes it has been demonstrated that this reaction is closely linked to the stimulation of the hexose monophosphate shunt (HMPS) [7,8] in activated cells.…”

Proliferação e diferenciação in vitro de células mononucleares medulares após estímulo com fatores de crescimento em ratos Wistar submetidos à dieta hiperlipídica

“…A viabilidade celular de todos os materiais biológicos foi avaliada por meio do teste de exclusão do azul de tripano 1% (CZARNETZKY; COWAN;BELCHER, 1975;FALLON et al, 1962;KING et al, 1959). Os resultados obtidos foram superiores a 90% de células viáveis para todos os ensaios realizados.…”