by Results expressed as mean quantity of pedicels SD were obtained from duplicate experiments (except for IgM experiment,n= 1) in which two randomly selected glomeruli were analysed from each animal, with a total of 250 m GBM analysed from each experiment The effects of administering 1.0 mg F(ab)1OX7 (n= 2), 0.03 and 0.1 mg OX7 (n= 2 each), and 0.4 mg IgM (n= 1) anti-Thy 1.1 monoclonal antibody on podocyte morphology in T16 mice were examined ultrastructurally. swelling was not altered by histamine or 5-hydroxytryptamine antagonists. OX7 did not cause match activation or leucocyte infiltration, hence glomerular injury appeared to be mediated directly by the antibody. Keywords:Thy 1.1 transgenic mice, OX7 monoclonal anti-Thy 1.1 antibody, podocyte foot process swelling, nonselective proteinuria, filtration slit membrane, microalbuminuria The glomerular podocyte is currently believed to have a role in regulating renal glomerular permeability, though the precise mechanism is controversial. Recent confocal microscopy permeability studies with acellular glomeruli (Danielset al. 1993) and detergent damaged single nephronsin vivo(Laurenset al. 1995) supports this view. It is generally considered that podocytes contribute a smaller part to the overall glomerular anionic charge barrier, but are believed to be the main determinants for hydraulic conductance and size selectivity (Danielset al. 1993;Drumond Oleanolic acid hemiphthalate disodium salt & Deen 1994) with the filtration slit probably taking part in an important role. Filtration slits are joined by modified variants of tight junctions, the filtration slit membranes, which divide the podocyte foot process plasma membrane into its apical (urinary side) and basal (GBM side) domains and provide the extracellular route for the ultrafiltrate. Although a model of the substructure of the filtration slit membrane has been proposed (Rodewald & Karnovsky 1974) information about molecular composition of filtration slit and membrane components is limited. Proteins such as ZO-1 (Schnabelet al. 1990;Kuriharaet al. 1995), 51 kD protein (Orikasaet al. 1988), and glycocalyx components: podocalyxin (Kerjaschkiet al. 1984;Sawadaet al. 1986), podoendin (Huang & Langlois 1985), and sialo-glycoprotein 115/107 (Mendrick & Rennke 1988b), are closely associated with these structures, but their functional relevance is usually unclear. Alterations in the morphology of the podocyte with foot process swelling are a prominent feature of human glomerulonephritides such as focal segmental glomerosclerosis and minimal switch glomerulonephritis and considerable effort has been devoted to the development of experimental systems of proteinuria and podocyte foot process damage. These include puromycin aminonucleoside or adriamycin nephrosis (Pricamet al. 1975;Whitesideet al. 1989), heterologous serum albumin injected rats and mice (Lannigan & McQueen 1962;Davies & Brewer 1977;Simpson & Shand 1983), enzymatic de-sialylationin vivo(Geldberget al. 1996), and administrationin vivoof monoclonal (Mendrick & Rennke 1988a;Orikasaet al. 1988;Assmannet al. 1992) or polyclonal (Salantet al. 1981;Piliaet al. 1983) nephritogenic antibodies. Transgenic mice transporting the Thy 1.1 gene in which the 3 untranslated sequence was replaced with a homologous region derived from human Thy-1 gene (T construct mice,Kolliaset al. 1987) ectopically express Thy 1.1 on podocytes. Although these animals Oleanolic acid hemiphthalate disodium salt develop spontaneous proteinuria later in life, they provide an opportunity for studying whether direct antibody binding to an ectopic molecule could cause podocyte injury. We report the effects of OX7in vivoin a heterozygous transgenic (T16) colony of mice. == Materials and methods == Fluorescein-labelled goat antimouse IgG (F(ab)1specific) antibody and mouse monoclonal IgM anti-Thy 1.1 antibody from clone Oleanolic acid hemiphthalate disodium salt TN-26 were purchased from Sigma-Aldrich (Poole, Dorset, UK). Fluorescein-labelled sheep anti mouse match C3 antibody was purchased from your Binding Oleanolic acid hemiphthalate disodium salt Site (Product No. PF280.U, Birmingham, UK). Mouse monoclonal anti-Thy 1.1 was purified, as described, from culture supernatant obtained from growth of clone MRC OX7. All other reagents were of analytical grade and purchased from standard suppliers. == Purification of OX7, F(ab)2OX7 and F(ab)1OX7 == Clone MRC OX7 was produced in culture in the Tecnomouse cell culture system (Integra Biosciences Ltd, St. Albans, UK) in RPMI 1640 medium supplemented with immunoglobulin-free foetal calf serum. Culture supernatant obtained after 11 days was fractionated by the addition of solid sodium sulphate at room temperature to a final concentration of 16%. The combination was centrifuged 3000 Rabbit polyclonal to Dcp1a g for 30 minutes at room temperature and the supernatant was discarded. The pellet re-dissolved in 0.9% saline was desalted, equilibrated and concentrated simultaneously by repeated.
