Vicia villosa lectin-positive neurones in human cerebral cortex. Loss in Alzheimer-type dementia.

Frontal and temporal sections of 4 normal human brains and 3 brains from patients with a diagnosis of Alzheimer-type dementia (ATD) were stained with Vicia villosa lectin conjugated to biotin to localize glycoproteins containing terminal N-acetylgalactosamine. These lectin binding sites were localized at the surface of a population of non-pyramidal interneurones. Examination of the co-existence of calbindin D28K or parvalbumin (PVA) with the lectin-binding material revealed that in the human cerebral cortex the lectin labelled only the PVA-immunoreactive neurones. Cell counts of the number of lectin-staining cells revealed that these cells are lost in ATD. The few remaining lectin-staining cells in ATD are shrunken and showed reduced expression of the lectin-staining material.