The 15.2 antibody reacts with human CD54, also known as ICAM-1 (Intercellular Adhesion Molecule 1), a 90-110 kDa cell surface glycoprotein that is inducibly expressed on both immune and endothelial cells. As its name implies, ICAM-1 participates in cell-cell adhesion between leukocytes and endothelial cells, facilitating leukocyte recruitment and transmigration at sites of inflammation. The ligands for ICAM-1 are also expressed on leukocyte and endothelial cells, and include Mac-1, fibrinogen, and a member of the integrin αprotein family, LFA-1 (CD11a).