Deferoxamine enhances phagocytic function of human polymorphonuclear leukocytes

Area of Science:

• Immunology
• Biochemistry
• Cell Biology

Background:

• Polymorphonuclear leukocytes (PMNs) generate toxic oxygen species, which can cause oxidative damage.
• Iron plays a role in the generation of these toxic oxygen species.
• Inhibiting iron-mediated damage may enhance PMN antibacterial functions.

Purpose of the Study:

• To investigate the effect of the iron chelator deferoxamine on the antibacterial function of PMNs.
• To determine if deferoxamine can protect PMNs from iron-mediated oxidative damage.
• To assess the impact of deferoxamine on bacterial uptake and intracellular killing by PMNs.

Main Methods:

• PMNs were incubated with various concentrations of deferoxamine.
• Bacterial uptake of radiolabeled Staphylococcus aureus was measured.
• Intracellular killing capacity, chemiluminescence, and superoxide production were assessed.
• Experiments included controls with non-incubated PMNs, PMNs incubated without deferoxamine, and PMNs treated with iron-saturated deferoxamine.

Main Results:

• Deferoxamine treatment (1 microM-1 mM) increased Staphylococcus aureus uptake by PMNs by 10%-20% compared to controls.
• This enhancement was not observed with iron-saturated deferoxamine.
• Intracellular killing capacity exceeded 90% for both deferoxamine-treated and control PMNs.
• Deferoxamine-treated PMNs showed enhanced chemiluminescence and superoxide production during phagocytosis.
• PMNs incubated with deferoxamine demonstrated improved bacterial killing capacity.

Conclusions:

• Deferoxamine enhances the antibacterial activity of PMNs.
• This enhancement is likely due to the protection of PMNs against iron-mediated generation of toxic oxygen metabolites.
• Deferoxamine may improve PMN phagocytic function and antibacterial efficacy.