THE DISTRIBUTION OF ALZ-50 IMMUNOREACTIVITY IN THE NORMAL HUMAN BRAIN

Alz-50 is a monoclonal antibody that recognizes normal tau proteins as well as phosphorylated tau proteins that are associated with paired h elical filaments in Alzheimer's disease. To establish an accurate base line for future pathological studies, we examined the distribution of Alz-50 immunoreactivity in normal human brain from infancy to senescen ce. We found extensive staining patterns of somata and axonal profiles in the striatum, amygdala, hypothalamus, brainstem and spinal cord in all normals at all ages. Similar normal staining patterns were seen i n the brains of patients who had suffered trauma, tumors, cerebral inf arcts, grade 1 periventricular hemorrhages, and in those who had suffe red from amyotrophic lateral sclerosis, Parkinson's disease, multi-sys tems atrophy and Shy-Drager syndrome. An absence of cell body staining and only minimal axonal staining was noted in the same brains with im munocytochemistry using PHF-1, a monoclonal antibody generated against paired helical filament proteins from Alzheimer brains. The character istic staining pattern of Alz-50 in normal brains is substantially mor e extensive than has previously been recognized. This pattern, which p resumably describes a specific class of tau proteins, must be distingu ished from the pathological staining observed in neurodegenerative dis eases.