A specific Fc gamma receptor on cultured rat mesangial cells

Journal Article · Sun Oct 15 04:00:00 EDT 1989 · Journal of Immunology; (USA)

OSTI ID:5189229

Santiago, A; Satriano, J; DeCandido, S; Holthofer, H; Schreiber, R; Unkeless, J; Schlondorff, D ^[1]

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1. Albert Einstein College of Medicine, NY (USA)

Mesangial cells represent specialized pericytes in the renal glomerulus that contribute to the regulation of a variety of glomerular functions. Recently we and others have shown that cultured mesangial cells bind and take up immune complexes in an Fc-dependent manner leading in turn to generation of PGE2, reactive oxygen, and platelet-activating factor. The present studies were designed to further characterize potential Fc-gamma R on mesangial cells. Binding assays with either monomeric or heat aggregated (HA) (125I) labeled rat subclass-specific IgG were performed at 4 degrees C for 2 h on subcultured rat mesangial cells. Monomeric rat IgG2a, IgG2b, IgG1 and HA IgG2a bound only nonspecifically. Saturable Fc-dependent binding occurred for HA IgG2b and HA IgG1 though maximal binding and affinity were much higher for IgG2b. The presence of an Fc-gamma R was confirmed by surface protein iodination of mesangial cells (MC) and immunoprecipitation with either a polyclonal or mAb 2.4G2 prepared against murine Fc-gamma R. Both antibodies precipitated a 45-kDa iodinated protein band from cultured rat MC that comigrated with that from murine macrophage J774 cells on SDS-PAGE. This protein band also reacted with the polyclonal anti Fc-gamma R antibody on immunoblots. In contrast rat renal papillary epithelial cells were negative. The 45-kDa protein recognized by the rat anti-Fc-gamma R antibody 2.4G2 probably represents the binding site for HA IgG2b, as the 2.4G2 antibody also blocked binding of HA IgG2b. By immunofluorescence microscopy all MC stained positively with the polyclonal anti-Fc-gamma R antibody. A cDNA probe for the Fc-gamma RII-alpha on murine macrophages hybridized to mRNA from cultured rat MC which was of the same size (though less abundant) as that from J774 macrophages.

• OSTI ID: 5189229
• Journal Information: Journal of Immunology; (USA), Journal Name: Journal of Immunology; (USA) Vol. 143:8; ISSN 0022-1767; ISSN JOIMA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMAL CELLS
ANIMAL TISSUES
ANIMALS
ANTIBODIES
ANTIGENS
BETA DECAY RADIOISOTOPES
BIOASSAY
BIOCHEMICAL REACTION KINETICS
BODY
CELL CULTURES
CONNECTIVE TISSUE CELLS
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
EPITHELIUM
FLUORESCENCE
GLOBULINS
IMMUNOASSAY
IMMUNOGLOBULINS
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KIDNEYS
KINETICS
LUMINESCENCE
MACROPHAGES
MAMMALS
MEMBRANE PROTEINS
MONOCLONAL ANTIBODIES
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANS
PHAGOCYTES
PROTEINS
RADIOISOTOPES
RATS
REACTION KINETICS
RECEPTORS
RODENTS
SOMATIC CELLS
TISSUES
TRACER TECHNIQUES
VERTEBRATES