Demonstration of the presence of an interleukin-1 receptor on the surface of murine astrocytes and its regulation by cytokines and Theiler's virus.

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 Kd = 0.3 x 10(-1) M), at a density of 150 receptors/cell. The specific, saturable and displaceable 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-regulated by Theiler's virus, interferon-gamma, tumour necrosis factor and IL-6; was not affected by vaccinia virus infection; and decreased after lipopolysaccharide treatment.