[Immunohistochemical analysis of protein gene product 9.5, a new marker for parietal epithelial cells of Bowman's capsules, in anti-glomerular basement membrane(GBM) antibody induced glomerulonephritis of WKY rats].

Protein gene product 9.5(PGP 9.5) is expressed specifically in neuroendocrine cells and considered to be one of the neuroendocrine markers. Recently, we reported that PGP 9.5 is localized in the parietal epithelial cells(PECs) of Bowman's capsules as well as in neural tissues. In the present study, immunohistochemical analysis of PGP 9.5 as a specific marker of the PECs of Bowman's capsules, synaptopodin as a podocyte-specific marker, and ED-1 as a specific marker of monocytes/macrophages was performed in the cellular crescents in anti-GBM antibody induced glomerulonephritis of WKY rats using serial renal sections. In the acute phase of anti-GBM antibody induced glomerulonephritis, and the expression of PGP 9.5 and ED-1 was observed diffusely in proliferating cells of cellular crescents. However, in most part of cellular crescents, PGP 9.5 positive areas did not overlap with the ED-1 positive areas. Synaptopodin was constantly detected along the glomerular tufts compressed by the crescents. In the chronic phase of this disease, PGP 9.5 was observed in the cells covering the surface of fibrous crescents or scattered within fibrocellular crescents. Synaptopodin was partially detected in such cells. It appears that cellular crescents are composed mainly of proliferating PECs and macrophages in rat anti-GBM antibody-induced glomerulonephritis.