Abstract
The localization of glomerular fibronectin (FN) was studied by double immunofluorescent microscopy (I. F.) using TRITC or FITC conjugated antibodies against glomerular basement membrane (GBM) and FN in 72 cases of human renal biopsy and in experimental glomerulonephritis (GN) in rats. Increase of glomerular FN was closely associated with mesangial proliferation and duplication of the glomerular capillary wall in membranoproliferative GN (type-1 MPGN), Double I. F. revealed subendothelial localization of FN in type-1 MPGN. A linear distribution of FN in membranous nephropathy had an accentuation on the inner aspect of the GBM. Segmental increase of FN on the GBM was prominent in focal glomerular sclerosis (FGS). The features of the FN localized along the GBM in BSA GN with diffuse capillary immune deposits appeared to resemble those of lupus GN. FN was localized predominantly in the mesangium in non-nephrotic Heymann's GN; however, a capillary localization similar to that in human membranous nephropathy appeared in the subsequent nephrotic period. Pretreatment studies on frozen sections of BSA GN indicated that FN was not localized in the three-dimensional structure of immune deposits.
