Antigenic expression of cathepsin B in aged human brain.

The lysosomal thiol proteinase, cathepsin B, has been localized in different regions of aged human brain by use of the peroxidase-antiperoxidase technique. Cathepsin B-immunoreactive material was detected in multiple neurons of human hippocampus, neocortical area A 10, prefrontal gyrus and nuc. basalis of Meynert as well as in single white matter astrocytes. In brains of Alzheimer disease-affected subjects cathepsin B was revealed in neuritic plaques too. Possible functional consequences with regard to normal aging, neuropeptide metabolism and pathological changes are discussed.