THE AMINO-TERMINALLY TRUNCATED FORMS OF AMYLOID BETA-PROTEIN IN BRAINMACROPHAGES IN THE ISCHEMIC LESIONS OF ALZHEIMERS-DISEASE PATIENTS

We have investigated the cerebral cortex of Alzheimer's disease in whi ch small infarcts are found on postmortem neuropathological examinatio n. In areas that have been subjected to recent ischemia, immunohistoch emical staining for amyloid beta-protein (A beta) is much less intense than in the non-ischemic surround. However, the infiltrating brain ma crophages contain granules immunopositive for C-terminal fragments of A beta. The immunohistochemical profile indicates that A beta in these granules lacks epitopes in the N-terminal fragments. These data sugge st that appropriately stimulated macrophages can phagocytose A beta de posits and that digestion of the N-terminal region is an early consequ ence of this phagocytosis.