Identification of monocyte chemoattractant protein-1 in senile plaques and reactive microglia of Alzheimer's disease.

It has been shown that human monocytes express monocyte chemoattractant protein-1 (MCP-1), an inflammatory factor, in response to non-fibrillar beta-amyloid protein. Reactive microglia and inflammatory factors were reported to be present in beta-amyloid deposits (senile plaques) in Alzheimer's disease, suggesting the presence of MCP-1 in senile plaques. To address this issue, we examined MCP-1 immunoreactivity in senile plaques using a mouse monoclonal anti-MCP-1 antibody. Monocyte chemoattractant protein-1 was found immunohistochemically in mature senile plaques and reactive microglia but not in immature senile plaques of brain tissues from five patients with Alzheimer's disease. These findings suggest that MCP-1-related inflammatory events induced by reactive microglia contribute to the maturation of senile plaques.