Binding patterns of mistletoe lectins I, II and III to microglia and Alzheimer plaque glycoproteins in human brains.

Glycoconjugates of microglial cells and in some cases those glycoconjugates present in the amyloid plaques in Alzheimer's disease in the cerebral cortex can be stained with a lectin from mistletoe (ML-I) using a labour-intensive and time-consuming indirect immunoperoxidase technique. In order to simplify the staining method and to test the staining characteristics of the other recently isolated mistletoe lectins (ML-II, ML-III) biotinylated MLs I-III were used together with an avidin-alkaline phosphatase-complex for visualisation. Our findings indicate that this new improved technique can also be used for detection of microglial cells and is considerably faster than the old method. In addition to microglial cells, ML-I labelled plaque glycoproteins possibly indicating that glycoconjugates derived from microglia can be detected in plaques. In contrast to ML-I, both ML-II and ML-III did not stain microglial cells.