Lymphocyte function-associated antigen 1 (LFA-1) is a leukocyte cell surface giycopmtein that promotes intelrceiiuiar adhesion in immunoiogicai and inflammatory reactions. it is an al3 complex that is structuraiiy related to receptors for extraceiiuiar matrix components, and thus belongs to the integrin family. iCAM-(intercellular adhesion molecule-l) is a distinct ceil surface giycoprotein. its broad distribution, mguiated expression in inflammation, and involvement in LFA-ldependent ceil-ceil adhesion have suggested that iCAM-may be a iigand for LFA-1. We have purified iCAM-and incorporated it into artificial supported lipid membmnes. LF&l+ but not LPA-l-ceils bound to CAY-1 in the artificiai membranes, and the bindlng could be specifically inhibited by anti-CAY-1 treatment of the membranes or by antMFA-1 treatment of the ceils. The ceil bindlng to CAM-1 requited metabolt energy production, an intact qtoskeieton, and the presence of Mg2+ and was temperature dependent, characteristics of LFA-l-and ICAM-l-dependent ceil-ceil adhesion.