LY-6C IS EXPRESSED IN BRAIN VESSELS ENDOTHELIAL-CELLS BUT NOT IN MICROGLIA OF THE MOUSE

The Ly-6C antigen is expressed in various cell types of the immune sys tem, including macrophages. Using the monoclonal antibody ER-MP20 whic h specifically recognises Ly-6C, we have investigated whether brain pa renchymatous microglia express Ly-6C in vivo as well as in vitro, in b rain sections from developing and adult C57/Bl mice, all vessels were strongly immunolabelled. Electron microscopic immunohistochemistry sho wed that the endothelial cells are the cell type expressing Ly-6C. In contrast, we never observed immunoreactivity on microglia; however, mi croglial cells proliferating in vitro were strongly ER-MP20 positive. These data show that Ly-6C is not a marker for microglia in vivo. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.