title: Immune inhibitory ligand CD200 induction by TLRs and NLRs limits macrophage activation to protect the host from meningococcal septicemia.
abstract: Macrophage activation is essential for protection against bacterial pathogens but needs to be regulated to prevent damage to the host. We show a key role for the immune inhibitory receptor CD200R and its ligand CD200 in the context of infection with the Gram-negative human pathogen Neisseria meningitidis. N. meningitidis induced CD200 but downregulated CD200R on macrophages in a manner dependent on Neisserial lipopolysaccharide, Toll-like receptor-4 (TLR-4), and the MyD88 pathway but independent of a known Neisserial receptor, scavenger receptor A (SR-A). Agonists of the pattern-recognition receptors nucleotide oligomerization domain 2 (NOD2) and NACHT-LRR protein 3 (NALP3) also induced CD200. The NF-κB member c-Rel was essential for TLR-, NOD2-, and NALP3-mediated induction of CD200. CD200(-/-) animals showed higher lethality in response to experimental meningococcal septicemia, induced higher levels of proinflammatory cytokines, and recruited increased numbers of activated leukocytes, despite comparable bacterial clearance. Thus CD200 is induced by TLR-, NOD2-, and NALP3-mediated pathways, limiting their function and protecting the host from excessive inflammation.
authors.affiliation: Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford, UK.
authors.forename: Subhankar
authors.initials: S
authors.lastname: Mukhopadhyay
authors.forename: Annette
authors.initials: A
authors.lastname: Plüddemann
authors.forename: J Claire
authors.initials: JC
authors.lastname: Hoe
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Williams
authors.forename: Audrey
authors.initials: A
authors.lastname: Varin
authors.forename: Katherine
authors.initials: K
authors.lastname: Makepeace
authors.forename: Marie-Laure
authors.initials: ML
authors.lastname: Aknin
authors.forename: Dawn M E
authors.initials: DM
authors.lastname: Bowdish
authors.forename: Stephen T
authors.initials: ST
authors.lastname: Smale
authors.forename: A Neil
authors.initials: AN
authors.lastname: Barclay
authors.forename: Siamon
authors.initials: S
authors.lastname: Gordon
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000235:genetics / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism*; D016207:Cytokines / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D005786:Gene Expression Regulation; D006801:Humans; D008070:Lipopolysaccharides / Q000276:immunology; D008262:Macrophage Activation; D017737:Macrophages, Peritoneal / Q000276:immunology* / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism*; D008589:Meningococcal Infections / Q000276:immunology*; D051379:Mice; D053594:Myeloid Differentiation Factor 88 / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein; D009345:Neisseria meningitidis / Q000276:immunology*; D053473:Nod2 Signaling Adaptor Protein / Q000378:metabolism*; D010538:Peritonitis / Q000276:immunology; D018805:Sepsis / Q000276:immunology; D015398:Signal Transduction; D051197:Toll-Like Receptor 4 / Q000378:metabolism; D051193:Toll-Like Receptors / Q000378:metabolism*
chemical_list: D015703:Antigens, CD; C492346:CD200 receptor, mouse; D002352:Carrier Proteins; D016207:Cytokines; D008070:Lipopolysaccharides; D008562:Membrane Glycoproteins; D053594:Myeloid Differentiation Factor 88; D016328:NF-kappa B; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein; C492716:Nlrp3 protein, mouse; D053473:Nod2 Signaling Adaptor Protein; C495945:Nod2 protein, mouse; D051197:Toll-Like Receptor 4; D051193:Toll-Like Receptors; C042739:antigens, CD200