title: Scavenger receptors and β-glucan receptors participate in the recognition of yeasts by murine macrophages.
abstract: OBJECTIVE
  Numerous receptors have been implicated in recognition of pathogenic fungi by macrophages, including the β-glucan receptor dectin-1. The role of scavenger receptors (SRs) in anti-fungal immunity is not well characterized.
  
  
  METHODS
  We studied uptake of unopsonized Saccharomycetes cerevisiae (zymosan) and live Candida albicans yeasts as well as zymosan-stimulated H(2)O(2) production in J774 macrophage-like cells and peritoneal exudate macrophages (PEMs). The role of different receptors was assessed with the use of competitive ligands, transfected cells and receptor-deficient macrophages.
  
  
  RESULTS
  The uptake of zymosan by untreated J774 cells was mediated approximately half by SRs and half by a β-glucan receptor which was distinct from dectin-1 and not linked to stimulation of H(2)O(2) production. Ligands of β-glucan receptors and of SRs also inhibited uptake of C. albicans by macrophages (J774 cells and PEMs). In macrophages pretreated with a CpG motif-containing oligodeoxynucleotide (CpG-ODN) the relative contribution of SRs to yeast uptake increased and that of β-glucan receptors decreased. Whereas the class A SR MARCO participated in the uptake of both zymosan and C. albicans by CpG-ODN-pretreated, but not untreated macrophages, the related receptor SR-A/CD204 was involved in the uptake of zymosan, but not of C. albicans. The reduction of zymosan-stimulated H(2)O(2) production observed in DS-pretreated J774 cells and in class A SRs-deficient PEMs suggest that class A SRs mediate part of this process.
  
  
  CONCLUSIONS
  Our results revealed that SRs belong to a redundant system of receptors for yeasts. Binding of yeasts to different receptors in resting versus CpG-ODN-pre-exposed macrophages may differentially affect polarization of adaptive immune responses.
authors: Department of Immunology, Jagiellonian University Medical College, 18 Czysta Street, 31-121, Kraków, Poland. szjozefowski@poczta.onet.pl
authors: Szczepan
authors: S
authors: Józefowski
authors: Zhiping
authors: Z
authors: Yang
authors: Janusz
authors: J
authors: Marcinkiewicz
authors: Lester
authors: L
authors: Kobzik
mesh_terms: D056704:Adaptive Immunity; D000818:Animals; D016466:CHO Cells; D002176:Candida albicans / Q000276:immunology*; D002460:Cell Line; D006224:Cricetinae; D003412:Cricetulus; D005260:Female; D006861:Hydrogen Peroxide / Q000378:metabolism; D017737:Macrophages, Peritoneal / Q000276:immunology* / Q000382:microbiology; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009838:Oligodeoxyribonucleotides / Q000494:pharmacology; D010587:Phagocytosis / Q000187:drug effects / Q000276:immunology; D011971:Receptors, Immunologic / Q000276:immunology*; D012441:Saccharomyces cerevisiae / Q000276:immunology*; D051117:Scavenger Receptors, Class A / Q000276:immunology*; D015054:Zymosan / Q000276:immunology / Q000378:metabolism
chemical_list: C408982:CPG-oligonucleotide; D009838:Oligodeoxyribonucleotides; D011971:Receptors, Immunologic; D051117:Scavenger Receptors, Class A; C045268:beta-glucan receptor; D015054:Zymosan; D006861:Hydrogen Peroxide