Lectin target cells in human central nervous system and the pituitary gland

Peanut lectin (PNL), Concanavalin A (Con A) and Ulex europaeus lectin I (Ulex) were chosen to map their binding sites in different regions of formalin fixed and paraffin embedded human central nervous system tissue and pituitary gland tissues. An extended PaP method was used for PNL and Ulex, whereas a direct peroxidase technique was employed for Con A. In astrocytes, the cytoplasm as well as the delicate processes were stained by PNL and Con A; the most conspicuous binding of PNL was seen in the ependymal cells and on the surface of plexus epithelial cells; in the anterior part of the pituitary gland a selective population was PNL positive. Intracytoplasmic Con A acceptors could be demonstrated in neurons, in ependymal cells, and in plexus epithelial cells. Intracytoplasmic Con A receptors were finely granular in astrocytes, oligodendrocytes, and in some cells in the pituitary gland. Ulex binding was restricted to the vascular endothelial cells and a selective population of cells in the pituitary gland. Our results suggest that lectins may be good tools for the evaluation of their respective target cells in the central nervous system and in the pituitary gland.