ICAM-1

Intra-cellular adhesion molecule one, ICAM-1 (CD54) weighs 75-115 Kd, and consists of five immunoglobulin like domains. It is constitutively expressed on endothelial and other cells. Expression of ICAM-1 is greatly increased by cytokine stimulation. It is the main binding site for the leukocyte $\beta _2$ integrins CD11a/CD18 (LFA-1) and CD11b/CD18 (Mac-1).

Binding of ICAM-1 to LFA-1 appears to be a crucial part of transmigration. Knockout Mice deficient in ICAM-1 show a significantly impaired granulocyte response to peritonitis. ICAM-1 antibodies reduce acute and chronic inflammation in a number of circumstances.