Microheterogeneity of the collecting duct system in rabbit kidney as revealed by monoclonal antibodies.

This report describes the immunolocalization of three monoclonal antibodies along the collecting duct system in rabbit kidney. The antibodies were raised against antigens derived from a membrane fraction of homogenized papillary tissue. Western Blot analysis demonstrated that each of the antibodies recognized a single band of about 190,000 (PCD1), 210,000 (PCD2) and 50,000 (PCD3) daltons. In renal tissue, the antibodies bound specifically to the epithelia of the connecting tubule (CNT), the collecting duct (CD) and the papillary surface epithelium. Differences in the binding patterns of the antisera were limited to the cortex. PCD1 labeled only a few scattered cells in the CNT, and exhibited a heterogeneous binding along the cortical collecting duct (CCD). PCD2 and PCD3 binding patterns were similar. In the CNT, these antibodies bound to the intercalated cells (IC-cells) but not to the CNT-cells proper. In the CCD, both IC-cells and principal cells were labeled. The binding to the medullary collecting duct by all three antisera was identical. The ureter was labeled only by PCD2 and PCD3, and none of the antisera bound to the bladder epithelium. The antibody binding patterns provide information concerning tubular axial heterogeneity and embryogenetic aspects of the CNT and the CCD. These antibodies may be used as differentiation markers in studies of the developing kidney and of renal tissue culture systems.