Alz-50/Gallyas-positive lysosome-like intraneuronal granules in Alzheimer's disease and control brains

The Gallyas-Braak silver impregnation method revealed neurons containing we ll-defined intraneuronal granules in both Alzheimer's disease and normal co ntrol brains. The granules were immunostained prominently with the Alz-50 a ntibody and, to a lesser degree, with the tau-e antibody, but not with othe r anti-tau antibodies examined. The areas of distribution of granule-contai ning neurons detected by the Gallyas-Braak method appeared to overlap with the reported main sites of subcortical distribution of neurofibrillary tang les. They, however, were not observed in the cerebral cortex, including the hippocampal region. The Alz-50 immunoreactive granules showed ultrastructu ral features similar to those of lysosomes or lipofuscin. These findings su ggest that denatured tau might be degraded in lysosomes. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.