Antibodies in the cerebrospinal fluid of some Alzheimer's disease patients recognize amoeboid microglial cells in the developing rat central nervous system.

Previous investigations have demonstrated that the cerebrospinal fluid from Alzheimer's disease patients contains antibodies that recognize specific neuronal populations in the adult rat central nervous system. These findings suggest a pathogenic role for immunological aberrations in this disorder. In the present report the investigation of antibodies in the cerebrospinal fluid of Alzheimer's disease patients was extended to developing rat central nervous system. The antibody in cerebrospinal fluid from Alzheimer's disease patients recognized entirely different types of antigens in the developing rat central nervous system as compared to adult rat central nervous system. One of the most remarkable differences was the recognition of amoeboid microglial cells. Diverse morphological forms of amoeboid microglial cells were observed, located mainly in the cavum septum pellucidum and in the corpus callosum. Electron microscopy revealed that the cerebrospinal fluid antibody from the Alzheimer's disease patients recognized specific membrane receptors in the macrophagic microglia. The unexpected recognition of amoeboid microglia by antibodies in Alzheimer's disease-cerebrospinal fluid is particularly interesting since these cells proliferate in response to nervous system disease and also engulf debris. The results add further support to the concept that inflammation and similar immune mechanisms may contribute to Alzheimer's disease pathogenesis.