Inoculation Study of Alzheimer Buffy Coat into Hamster Brain

Abstract

Buffy coats from 4 members of a family with Alzheimer''s disease and 2 genetically unrelated healthy subjects were inoculated into the hamster brain. Eighteen months after the inoculation, the brains were studied by immunostaining with antibodies against neurofilaments, tau, ubiquitin, and paired-helical filaments (PHF) as well as by electron microscopy. Vacuolar or spongioform degeneration was minimum. Intense positive staining by antibodies against neurofilament 200K protein was demonstrated in neuronal perikarya of the lower brain stem nucleus in the hamster inoculated with the buffy coats from the 2 patients with Alzheimer''s disease and 2 children of the patient, which was not observed in the hamster brain inoculated with the buffy coat from the control subjects. Electron microscopy revealed intracytoplasmic accumulation of 10-nm neurofilament-like fibers. The accumulated neurofilaments were positively stained by antitau and antiubiquitin, but not by anti-PHF. The neurons containing massive intracytoplasmic neurofilament accumulation resembled ballooned neurons in some degenerative diseases including Alzheimer''s disease. The results indicate that the buffy coat obtained from the patients and members of a family with Alzheimer''s disease contains a factor which produces intracytoplasmic accumulation of neurofilament-like fibers in neurons of the lower brain stem nuclei.