Fig. 1

Mesangial cells were cultured from renal biopsies, characterized and treated with IgA. Schematic figure of harvest and culture of mesangial cells (a). Mesangial cells growing out from glomeruli (b). Immunofluorescence microscopy of smooth muscle actin labeling in mesangial cells. Smooth muscle actin is exclusively localized to the mesangial cells in the glomeruli. Mesangial cells cultured from glomeruli from renal biopsies were stained using an anti-smooth muscle actin antibody (green). Nuclei are stained blue with DAPI. Magnification 20× (c), 40× (d). The mesangial cells were negative for endothelial and podocyte markers, see Methods. IgA1 purified from human blood was run on HPLC to detect different sizes of IgA1 (e). A representative sandwich ELISA shows that IgA1 purified from patients with IgAN have a higher amount of gd-IgA than IgA1 purified from controls (f)