Naturally occurring and experimentally induced β-amyloid deposits in the brains of marmosets (Callithrix jacchus)

Summary.

Cerebral β-amyloid occurs in elderly animals of some species and in Alzheimer's disease. Previously, we injected 3 young marmosets intracerebrally with brain tissue from a patient with Alzheimer's disease. Six years later, when the monkeys were middle aged, we found moderate numbers of intracerebral plaques and cerebrovascular deposits containing β-amyloid. We have re-examined these brains and those of 10 other marmosets injected with brain homogenate containing β-amyloid, and have found some β-amyloid in animals injected more than 4 years previously. We have found β-amyloid in 4 of 26 elderly control marmosets, but not in 9 young to middle-aged control marmosets. The β-amyloid found in middle aged marmosets injected with Alzheimer brain tissue was, therefore, not a consequence of their age. Deposits in large cerebral vessels in elderly marmosets, and in marmosets previously injected with brain tissue containing β-amyloid, reacted with antibodies to Aβ and Aβ1-40; plaques and microvessel deposits reacted with antibodies to Aβ and Aβ1-42.