CEREBRAL ENDOTHELIAL-CELLS ARE A MAJOR SOURCE FOR SOLUBLE INTERCELLULAR-ADHESION MOLECULE-1 IN THE HUMAN CENTRAL-NERVOUS-SYSTEM

Immunohistological analysis of tissue sections from human brain reveal ed that intercellular adhesion molecule-1 (ICAM-1) is mainly expressed on endothelial cells of small vessels, including the subependymal ves sels of the choroid plexus. In addition, it is expressed on cerebrospi nal fluid (CSF) cells in patients with inflammatory diseases of the ce ntral nervous system. Stimulation of confluent monolayers of adult hum an cerebral endothelial cells with lipopolysaccharide (LPS) or recombi nant human tumor necrosis factor-alpha (TNF-alpha) could induce expres sion and secretion of soluble ICAM-1 in a dose dependent manner, In ad dition, sICAM-1 was also present in the supernatant from U251 glioma c ells. No sICAM was detected in the culture supernatant from activated blood or CSF lymphocytes. Cerebral endothelial cells are therefore a l ikely source for sICAM-1 in the CSF.