Heterogenous glycosylation of ICAM-3 and lack of interaction with Mac-1 and p150,95

Intercellular adhesion molecule (ICAM)-1, ICAM-2, and ICAM-3 have been identified as counter-receptors for the leukocyte integrin lymphocyte function-associated antigen 1 (LFA-1). The other leukocyte integrins, Mac-1 and p150,95, also interact with ICAM-1. ICAM-1 and ICAM-3 are highly homologous, and an undefined ligand for Mac-1 is present on neutrophils where ICAM-3 is well expressed. In addition, glycosylation has been shown to affect the interaction of ICAM-1 with Mac-1. We therefore sought to characterize ICAM-3 heterogeneity and determine whether ICAM-3 was a ligand for either Mac-1 or p150,95. Despite extensive differences in N-linked glycosylation, ICAM-3 purified from lymphoid cells and from neutrophils supports adhesion of LFA-1-bearing cells equally well; however, neither supports adhesion of Mac-1 or p150,95-expressing chinese hamster ovary cell transfectants. Similarly, purified Mac-1 does not support adhesion of ICAM-2 or ICAM-3-expressing L cell transfectants. ICAM-3 on neutrophils does not participate in Mac-1-dependent homotypic aggregation. Thus, ICAM-3 is not a counter-receptor for either Mac-1 or p150,95.