Artificial opsonin enhances bacterial phagocytosis, oxidative burst and chemokine production by human neutrophils

作者：Katzenmeyer Kristy N; Szott Luisa M; Bryers James D^*

来源：Pathogens and Disease, 2017, 75(6): ftx075.

DOI：10.1093/femspd/ftx075

• artificial opsonin
• innate response
• phagocytosis
• neutrophils

Here, we describe the application of an `artificial opsonin' to stimulate the innate immune response against Gram-positive bacteria. The artificial opsonin comprises a poly(L-lysine)-graft-poly(ethylene glycol) backbone displaying multiple copies of vancomycin and human IgG-Fc gamma The vancomycin targets bacteria by recognizing D-Ala-D-Ala-terminated peptides present in the bacterial cell wall. The human IgG-Fc antibody fragments serve as phagocyte recognition moieties that recognize the Fc gamma cell surface receptors expressed by professional human phagocytes. Staphylococcus epidermidis RP62A, a biofilm-forming, methicillin- resistant strain, was utilized to investigate the effects of opsonization on phagocytosis, oxidative burst and IL-8 chemokine production by human neutrophils. Results show that opsonization of S. epidermidis RP62A with the artificial opsonin resulted in an similar to 2-fold increase in neutrophil phagocytosis. Analysis of the cell supernatant found a 2- to 3-fold increase in neutrophil IL-8 secretion. The neutrophil oxidative burst was investigated using the oxidation-sensitive fluorophore dihydrorhodamine-123. Bacterial opsonization resulted in a 20% increase in fluorescence intensity, indicating a significant increase in the production of reactive oxygen species by the neutrophils. These studies suggest that artificial opsonins may be a novel immunostimulation therapeutic strategy to control infections caused by Gram-positive bacteria, particularly those that are known to be immune evasive and/or antibiotic resistant.

• 出版日期2017-8