The acute-phase reactant C-reactive protein binds to phosphorylcholine-expressing Neisseria meningitidis and increases uptake by human phagocytes.
Neisseria meningitidis is a global cause of meningitis and septicemia. Immunity to N. meningitidis involves both innate and specific mechanisms with killing by serum bactericidal activity and phagocytic cells. C-reactive protein (CRP) is an acute-phase serum protein that has been shown to help protect the host from several bacterial pathogens, which it recognizes by binding to phosphorylcholine (PC) on their surfaces. Pathogenic Neisseria species can exhibit phase-variable PC modification on type 1 and 2 pili. We have shown that CRP can bind to piliated meningococci in a classical calcium-dependent manner. The binding of CRP to the meningococcus was concentration dependent, of low affinity, and specific for PC. CRP appears to act as an opsonin for N. meningitidis, as CRP-opsonized bacteria showed increased uptake by human macrophages and neutrophils. Further investigation into the downstream effects of CRP-bound N. meningitidis may lead us to a better understanding of meningococcal infection and help direct more effective therapeutic interventions.
Casey
Rosalyn
R
Division of Microbial Sciences, Faculty of Health and Medical Sciences, University of Surrey, Stag Hill, Guildford, Surrey GU2 7XH, United Kingdom.
Newcombe
Jane
J
McFadden
Johnjoe
J
Bodman-Smith
Katherine B
KB
D002097:C-Reactive Protein / Q000276:immunology* / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D002460:Cell Line; D002478:Cells, Cultured; D004306:Dose-Response Relationship, Immunologic; D006801:Humans; D008264:Macrophages / Q000276:immunology; D009345:Neisseria meningitidis / Q000276:immunology* / Q000378:metabolism*; D009504:Neutrophils / Q000276:immunology; D010586:Phagocytes / Q000276:immunology*; D010767:Phosphorylcholine / Q000378:metabolism*; D011485:Protein Binding
D010767:Phosphorylcholine; D002097:C-Reactive Protein; D002118:Calcium