ROLE OF ADHESION MOLECULES OF THE SELECTIN-CARBOHYDRATE FAMILIES IN ANTIBODY-DEPENDENT CELL-MEDIATED CYTOXICITY TO SCHISTOSOME TARGETS

The role of adhesion molecules in antibody-dependent cell-mediated cyt otoxicity (ADCC) of macrophages toward the extracellular parasite Schi stosoma mansoni was investigated by using 1) a panel of blocking mAbs directed against adhesion molecules and 2) different soluble ligands a s candidate inhibitors of ADCC, The results show that the beta(2)-inte grin Mac-1 (CD11b/CD18), L-selectin (CD62-L), and the carbohydrate det erminant sialyl Lewis(x) (sLe(x); sCD15) are required for macrophage e ffector function toward schistosomula targets, On the other hand, the parasite counter-receptors involved in ADCC were found to share common motifs with the mammalian selectin-carbohydrate families. One family of parasite receptor(s) involved in ADCC carries the Lewis(x) (Le(x); CD15) carbohydrate structure, whereas a second family of receptor(s) a ppears to display selectin-like properties with affinity for the sLe(x ) tetrasaccharide. Immunostaining experiments confirmed that schistoso mula express on their surface hostlike molecules recognized by anti-le (x) (CD15) and by anti-human E-selectin (CD62-E) mAbs, The double rece ptor-ligand interaction between macrophages and parasite targets provi des new insights into the biologic roles of selectins and Le(x)-relate d structures in immunity against helminthic parasites.