DEMONSTRATION OF THE PRESENCE OF AN INTERLEUKIN-1 RECEPTOR ON THE SURFACE OF MURINE ASTROCYTES AND ITS REGULATION BY CYTOKINES AND THEILERSVIRUS

Interleukin-1 (IL-1) binding found in rodent brain, and its biological effect on astroglial cells, suggests that the receptor for IL-1 alpha may be located on astrocytes. A radioligand receptor assay performed on pure mouse astrocyte cultures revealed the presence of one binding site [type I, molecular weight (MW) 80,000], with K-d = 0.3 X 10(-10) M, at a density of 150 receptors/cell. The specific, saturable and dis placeable high-affinity binding took place in a time- and temperature- dependent way. The receptor-IL-1 alpha complex was quickly endocytosed at 37 degrees but not at 4 degrees. The receptor expression was up-re gulated by Theiler's virus, interferon-gamma, tumour necrosis factor a nd IL-6; was not affected by vaccinia virus infection; and decreased a fter lipopolysaccharide treatment.