title: Retinal microglia differentially express phenotypic markers of antigen-presenting cells in vitro.
abstract: OBJECTIVE
  Retinal microglial cells of newborn Lewis rats were isolated and cultured, and the effect of macrophage colony-stimulating factor (M-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF), and interferon-gamma (IFN-gamma) on microglial expression of the accessory molecules required for antigen presentation were studied.
  
  
  METHODS
  Retinal microglia were isolated from newborn Lewis rats and cultured in media supplemented with either M-CSF or GM-CSF. Immunohistochemical tests using anti-macrophage complement receptor 3 (OX42) or anti-monocyte-macrophage (ED1) and DiI-ac-low-density lipoprotein (LDL) uptake were used to identify microglia. The effect on accessory molecule expression of microglial cells cultured under varying conditions (M-CSF, GM-CSF, and M-CSF plus IFN-gamma) was analyzed by fluorescence-activated cell sorter, using one of the following antibodies: anti-OX3, anti-OX6, anti-rat intercellular adhesion molecule (ICAM)-1, anti-rat B7-1, or anti-rat B7-2.
  
  
  RESULTS
  The cultured retinal microglia were positive for macrophage-related antigens (ED1 and OX42) and also showed uptake of LDL. Furthermore, ICAM-1 and B7-2 were expressed constitutively on these cells, and MHC class II and B7-1 were also expressed after IFN-gamma stimulation.
  
  
  CONCLUSIONS
  In vitro, the retinal microglia express the molecules required for effective antigen presentation to CD4-positive T cells. These findings suggest that microglia may play a role in local antigen presentation, especially when they are exposed to IFN-gamma.
authors.affiliation: Doheny Eye Institute and the Department of Ophthalmology, University of Southern California, School of Medicine, Los Angeles 90033-1088, USA.
authors.forename: T
authors.initials: T
authors.lastname: Matsubara
authors.forename: G
authors.initials: G
authors.lastname: Pararajasegaram
authors.forename: G S
authors.initials: GS
authors.lastname: Wu
authors.forename: N A
authors.initials: NA
authors.lastname: Rao
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D000938:Antigen-Presenting Cells / Q000737:chemistry / Q000166:cytology / Q000378:metabolism*; D000954:Antigens, Surface / Q000378:metabolism; D018122:B7-1 Antigen / Q000378:metabolism; D015415:Biomarkers / Q000032:analysis*; D002232:Carbocyanines / Q000378:metabolism; D002469:Cell Separation; D002478:Cells, Cultured; D005434:Flow Cytometry; D005456:Fluorescent Dyes / Q000378:metabolism; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D000949:Histocompatibility Antigens Class II / Q000378:metabolism; D007124:Immunoenzyme Techniques; D016130:Immunophenotyping; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism; D007371:Interferon-gamma / Q000494:pharmacology; D008077:Lipoproteins, LDL / Q000378:metabolism; D016173:Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D017628:Microglia / Q000737:chemistry / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D011917:Rats, Inbred Lew; D012160:Retina / Q000737:chemistry / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*
chemical_list: D000954:Antigens, Surface; D018122:B7-1 Antigen; D015415:Biomarkers; D002232:Carbocyanines; D005456:Fluorescent Dyes; D000949:Histocompatibility Antigens Class II; D008077:Lipoproteins, LDL; D018799:Intercellular Adhesion Molecule-1; C024286:3,3'-dioctadecylindocarbocyanine; D016173:Macrophage Colony-Stimulating Factor; D007371:Interferon-gamma; D016178:Granulocyte-Macrophage Colony-Stimulating Factor