Abstract
Atypical bovine spongiform encephalopathy (atypical BSE) has recently been identified in several countries including Japan. Most cases of atypical BSE have been reported in cattle older than 8 years of age. To clarify the association between age and occurrence of atypical BSE, we investigated both the physiological properties and amount of cellular prion protein (PrPC) in brain homogenates from young and aged cattle by enzyme-linked immunosorbent assay and immunoblotting. The amount of PrPC in the brain homogenates was not significantly different between young and aged cattle, but the amount in the detergent-insoluble fraction in the aged cattle was significantly higher than that of young cattle. Significant differences were observed in neither of the glycosylation forms nor in proteinase K sensitivity in young and aged cattle. Age-related changes included deposition of lipofuscin pigment and a decrease of 33% in proteasome activity in the brains of aged cattle compared to that of young cattle.
