Immunocytochemical studies of Alzheimer neuronal perikarya with intermediate filament antisera

Isolated neuronal perikarya from the brains of patients with Alzheimer's disease were examined in indirect immunofluorescence microscopy with different types of specific antisera against the subunit proteins of cytoskeletal intermediate filaments. From 30 to 50% of the neurofibrillary tangles were stained with antisera against each of the neurofilament triplet proteins, but not with antisera against glial fibrillary acidic protein, vimentin, desmin or cytokeratin. Polyacrylamide gel electrophoresis of Alzheimer perikaryal fractions showed polypeptide patterns markedly similar to control neuronal fractions. Our results thus suggest either that the Alzheimer neurofibrillary tangles and the antigenic neurofilament triplet protein fractions may contain related antigenic determinants or that unaffected perikaryal neurofilament material is associated with the tangles.