Inhibition of the respiratory burst of human neutrophils by the polyamine oxidase-polyamine system.

The addition of the polyamines, spermine and spermidine, to human neutrophils caused a depression of the hexose-monophosphate (HMP) shunt activity of neutrophils stimulated with latex particles but not of unstimulated cells. The effect was dependent on the presence of bovine serum and was not observed when normal human serum was substituted for bovine serum. The polyamine oxidase (PAO) in bovine serum was probably responsible for generating the activity since normal human serum lacks PAO. A role for PAO was further supported by the finding that partially purified bovine PAO in the presence of polyamines similarly mediated inhibition of HMP shunt activity in stimulated neutrophils. Catalase failed to prevent the inhibitory effects of the PAO-polyamine system suggesting that H2O2 is not the responsible product. In addition, our results show that human pregnancy serum known to contain PAO activity in the presence of polyamines mediated a similar inhibition of the respiratory burst.

Enhancement of base hexose-monophosphate shunt activity of human polymorphonuclear leucocytes by human beta-interferon.

The effect of human fibroblast interferon (HuIFN-beta) on the HMP shunt activity of human polymorphonuclear leucocytes (PMNLs) was examined. HuIFN-beta caused an increase in the base level of the HMP shunt activity. No significant increase was observed in the same PMNLs stimulated with opsonized zymosan. The augmentation of this property, generally associated with antimicrobial and cytotoxic properties of the PMNLs, may be of potential importance in host defences against microbial and malignant diseases.

Improved method for neutrophil hexose-monophosphate shunt assay using serum.

The addition of serum into the hexose-monophosphate shunt assay results in the reduction of neutrophil resting metabolic activity. This results in a higher stimulation index and consistent values.