K. Kobayashi et al., KP-1 IS A MARKER FOR EXTRANEURONAL NEUROFIBRILLARY TANGLES AND SENILEPLAQUES IN ALZHEIMER DISEASED BRAINS, Dementia and geriatric cognitive disorders, 9(1), 1998, pp. 13-19
KP-1 immunostaining with microwave pretreatment in formalin-fixed, par
affin-embedded sections enhanced its immunoreactivity revealing extran
euronal neurofibrillary tangles (NFTs) called ghost tangles, senile pl
aques (SPs) and perivascular deposits as well as microglial labelling
in Alzheimer-diseased brains. KP-1 stained cored and uncored SPs, gran
ules within the SPs, perivascular beta-amyloid protein (beta AP) and s
tar-like beta AP deposits in cortical layer I, which was confirmed in
comparison to silver-impregnated structures in the Reusche-stained or
Gallyas-Schiff-stained sections. On double immunostaining with KP-1 an
d ubiquitin, ghost tangles were labelled by KP-1 and intraneuronal NFT
s were positive for ubiquitin. A few KP-1-positive granules deposits d
ifferent from amyloid core were found within the SPs and the outer mar
gin of amyloid cores of SPs were stained by KP-1. KP-1-positive microg
lia were attached to the ubiquitin-positive intraneuronal NFTs. Microg
lia were more numerously labelled by CR3/43 than by KP-1, and CR3/43-p
ositive microglia were found to be preferentially attached to SPs. As
KP-1 recognizes lysosome-associated antigen CD68, similarities between
KP-1 positivity and Reusche-stained structures suggested that lysosom
al activity was associated with beta AP deposits and ghost tangles wer
e involved in lysosome-associated processes. It is speculated that lys
osomes play a role in the process of ghost tangle formation and in bet
a AP deposits leading to SP formation.