Reconstitution of bactericidal activity in chronic granulomatous disease cells by glucose-oxidase-containing liposomes

Chronic granulomatous disease (CGD) is an inherited primary immunodeficienc y characterized by phagocytes devoid of a functioning nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. The failure of CGD phagocytes to pr oduce reactive oxygen species (ROS) results in a marked increase in the sus ceptibility of affected patients to life-threatening bacterial and fungal i nfections. This study investigated whether [loading of CGD phagocytes with glucose oxidase (GO)containing liposomes (GOLs) could restore cellular prod uction of bactericidal ROS (eg, H2O2 and HOCl) in vitro. Results indicate t hat GO encapsulated in liposomes enabled NADPH oxidase-deficient phagocytes to use H2O2 for the production of highly bactericidal HOCL The intracellul ar colocalization of bacteria and liposomes (or liposome-derived ferritin) was demonstrated by confocal laser microscopy and electron microscopy. Afte r uptake of GOLs (approximately 0.2 U/mL at 1 mM total lipid concentration, size approximately 180 nm), CGD granulocytes produced HOCl levels comparab le to those of normal phagocytes. Remarkably, after treatment with GOLs, CG D phagocytes killed Staphylococcus aureus as efficiently as normal granuloc ytes. Moreover, treated cells retained sufficient motility toward chemotact ic stimuli as measured by chemotaxis assay. Side effects were evaluated by measuring the H2O2 concentrations and the production of methemoglobin in wh ole blood. These studies revealed that H2O2 produced by GOLs was degraded i mmediately by the antioxidative capacity of whole blood. Elevated methemogl obin levels were observed only after application of extremely high amounts of GOLs (2 U/mL). In summary, the application of negatively charged GOLs mi ght provide a novel effective approach in the treatment of patients with CG D at high risk for life-threatening infections. (C) 2001 by The American So ciety of Hematology.