title: Effects of C-reactive protein on the neutrophil respiratory burst in vitro.
abstract: This study determined the influence of physiologically relevant concentrations of C-reactive protein (CRP) on reactive oxygen species (ROS) production by neutrophils. Neutrophils from healthy individuals were incubated with soluble pentameric CRP prior to TLR stimulation with Fusobacterium nucleatum, or FcγR stimulation with IgG-opsonised Staphylococcus aureus or heat-aggregated IgG. ROS generation by unstimulated cells and those after stimulation were determined using luminol, isoluminol and lucigenin chemiluminescence, detecting predominantly intracellular hypochlorous acid (HOCl), extracellular hydrogen peroxide (detected as HOCl) and extracellular superoxide respectively. Baseline (unstimulated) neutrophil ROS generation and release was reduced compared with vehicle control by 10 µg/ml CRP. There was no consistent effect of CRP on FcγR-stimulated HOCl production, but the extracellular superoxide response was reduced by 10 µg/ml CRP. By contrast, CRP reduced intracellular (10 µg/ml) and extracellular (3 and 10 µg/ml) HOCl generation, but increased superoxide release (1-10 µg/ml) in response to TLR stimulation. Physiologically relevant concentrations of CRP inhibited baseline ROS generation and reduced FcγR-stimulated extracellular superoxide and TLR-stimulated HOCl release, suggesting that CRP may offer some degree of host protection from neutrophil-associated, low-level oxidative stress. However, CRP enhanced TLR-mediated superoxide release from neutrophils, potentially increasing oxidative stress but aiding host protection from infection.
authors.affiliation: Periodontal Research Group and MRC Centre for Immune Regulation, College of Medical and Dental Sciences, The University of Birmingham, Birmingham, UK.
authors.forename: Martin R
authors.initials: MR
authors.lastname: Ling
authors.forename: Iain L C
authors.initials: IL
authors.lastname: Chapple
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Creese
authors.forename: John B
authors.initials: JB
authors.lastname: Matthews
mesh_terms: D002097:C-Reactive Protein / Q000378:metabolism*; D002478:Cells, Cultured; D005674:Fusobacterium Infections / Q000378:metabolism*; D016967:Fusobacterium nucleatum / Q000502:physiology*; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D006997:Hypochlorous Acid / Q000378:metabolism; D066298:In Vitro Techniques; D009504:Neutrophils / Q000378:metabolism*; D018384:Oxidative Stress; D017452:Receptors, IgG / Q000378:metabolism; D013203:Staphylococcal Infections / Q000378:metabolism*; D013211:Staphylococcus aureus / Q000502:physiology*; D013481:Superoxides / Q000378:metabolism; D051193:Toll-Like Receptors / Q000378:metabolism
chemical_list: D017452:Receptors, IgG; D051193:Toll-Like Receptors; D013481:Superoxides; D006997:Hypochlorous Acid; D002097:C-Reactive Protein; D006861:Hydrogen Peroxide
keywords: C-reactive protein; neutrophil; periodontitis; reactive oxygen species; respiratory burst