IDENTIFICATION OF FC-GAMMA-RI, II AND III ON NORMAL HUMAN BRAIN RAMIFIED MICROGLIA AND ON MICROGLIA IN SENILE PLAQUES IN ALZHEIMERS-DISEASE

Using monoclonal antibodies to the three known human leukocyte IgG receptors, FcgammaR, we examined the expression of FcgammaR in normal brains and in Alzheimer's disease. We found FcgammaRI, II and III immunoreactivity in senile plaques and on ramified microglia throughout the cortex and white matter of normal and Alzheimer's disease brains. FcgammaRI expression was independently confirmed by a murine isotype binding study. These findings suggest that intrinsic FcgammaR may play an important role in normal and disordered immune-related processes in the brain. They support the idea that microglia are brain macrophages.