Podocytes in glomerulus of rat kidney express a characteristic 44 KD protein.

作者：Peter H. Mundel, Peter B. Gilbert, Wilhelm Kriz · 发表于：Journal of Histochemistry & Cytochemistry · 年份：1991 · DOI：10.1177/39.8.1856454 · 被引用次数：147 · 研究领域：Renal Diseases and Glomerulopathies、Galectins and Cancer Biology、Wnt/β-catenin signaling in development and cancer

We describe a new monoclonal antibody (MAb) directed against glomerular visceral epithelial cells (podocytes), generated by immunization with isolated rat kidney glomeruli. In immunoblotting experiments this MAb (IgG1 subclass) reacted with a 44 KD protein. In cryostat sections of normal rat kidney the MAb stained glomerular podocytes; therefore, we called the antigen pp44 (podocyte protein 44 KD). On 0.5-micron cryostat sections the signal could be more precisely ascribed to the podocyte foot processes, whereas the cell bodies appeared virtually unreactive. On ultra-thin frozen sections pp44 was found within the cytoplasm of podocyte foot processes at their origin from their parent processes. The podocyte cell membrane was not labeled. All other parts of the nephron were unreactive. An additional but weaker immunoreaction was found in the arterial endothelium; the endothelia of other vessels (peritubular capillaries, veins) were negative. In human kidney anti-pp44 revealed the same staining pattern as in rat kidney. The expression of pp44 was also studied in newborn rat kidney. The early stages of glomerular development (renal vesicle, S-shaped body) were negative. pp44 first appeared during the capillary loop stage, i.e., when formation of podocyte foot processes commences. In comparing the present results with published data, pp44 is clearly different from other antigens thus far described in podocytes. From the results of this investigation we conclude that pp44 represent...