title: Role of the mannose receptor (CD206) in innate immunity to ricin toxin.
abstract: The entry of ricin toxin into macrophages and certain other cell types in the spleen and liver results in toxin-induced inflammation, tissue damage and organ failure. It has been proposed that uptake of ricin into macrophages is facilitated by the mannose receptor (MR; CD206), a C-type lectin known to recognize the oligosaccharide side chains on ricin's A (RTA) and B (RTB) subunits. In this study, we confirmed that the MR does indeed promote ricin binding, uptake and killing of monocytes in vitro. To assess the role of MR in the pathogenesis of ricin in vivo, MR knockout (MR(-/-)) mice were challenged with the equivalent of 2.5× or 5× LD(50) of ricin by intraperitoneal injection. We found that MR(-/-) mice were significantly more susceptible to toxin-induced death than their age-matched, wild-type control counterparts. These data are consistent with a role for the MR in scavenging and degradation of ricin, not facilitating its uptake and toxicity in vivo.
authors: Division of Infectious Disease, Wadsworth Center, New York State Department of Health, Albany, NY 12208, USA. gage.emily@gmail.com
authors: Emily
authors: E
authors: Gage
authors: Maria O
authors: MO
authors: Hernandez
authors: Joanne M
authors: JM
authors: O'Hara
authors: Elizabeth A
authors: EA
authors: McCarthy
authors: Nicholas J
authors: NJ
authors: Mantis
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D016207:Cytokines / Q000276:immunology; D005260:Female; D006801:Humans; D007113:Immunity, Innate / Q000187:drug effects*; D037181:Lectins, C-Type / Q000502:physiology*; D007962:Leukocytes / Q000187:drug effects; D008264:Macrophages / Q000187:drug effects; D008297:Male; D000090323:Mannose Receptor; D037241:Mannose-Binding Lectins / Q000502:physiology*; D051379:Mice; D018345:Mice, Knockout; D011956:Receptors, Cell Surface / Q000502:physiology*; D012276:Ricin / Q000097:blood / Q000493:pharmacokinetics / Q000633:toxicity*
chemical_list: D016207:Cytokines; D037181:Lectins, C-Type; D000090323:Mannose Receptor; D037241:Mannose-Binding Lectins; D011956:Receptors, Cell Surface; D012276:Ricin