The HNK-1
carbohydrate epitope is a 3-sulfo-glucuronyl residue attached to
lactosamine structures on
glycoproteins,
proteoglycans, or
glycolipids mostly expressed in the nervous system. Here, using
monoclonal antibodies against the sulfated HNK-1
carbohydrate epitope, we first examined its distribution in developing and adult kidneys, then its expression in kidneys with tubular
necrosis and
renal neoplasms. This HNK-1
epitope was expressed in the human, rabbit, and rat, but not mouse kidney. It was detected within a subset of epithelial cells in the renal vesicle and in comma- and S-shaped bodies during early stages of nephrogenesis. In ureteral bud derivatives, the
epitope was present transiently in the area where the collecting duct fused with the nephron. In the adult kidney, expression of the HNK-1
epitope became mainly restricted to the thin ascending loop of Henle where this
epitope was carried by heparan- and chondro-
proteoglycan. In pathological conditions, HNK-1
epitope expression increased dramatically in proximal epithelial tubule cells in kidneys with acute tubular
necrosis. In
tumors, the HNK-1
epitope was expressed in the epithelial component of
nephroblastomas and in a subgroup of papillary
renal cell carcinomas. These data suggest that molecules carrying the sulfated HNK-1
carbohydrate epitope may play an important role in critical stages of renal development and in the physiology of thin ascending loop of Henle.