Staining of cerebral amyloid plaque glycoproteins in patients with Alzheimer's disease with the microglia-specific lectin from mistletoe.

Glycoconjugates in the amyloid plaques in the cerebral cortex of patients with Alzheimer's disease were stained with a lectin from mistletoe (ML-I). This lectin selectively stains microglial cells which can be found in the centre of many plaques. Since the terminal carbohydrate moieties of some but not all of the plaques, which mainly consist of beta A4 protein, are identical to those of the microglial cells it is concluded that glycoproteins within these plaques have been synthesised by the microglial cell. These microglia deposited glycoproteins may be of importance for the formation of mature amyloid plaques.