The E-selectin ligand-1 (ESL-1) has recently been identified as the major ligand on mouse neutrophils using a recombinant antibody-like form of E-selectin as affinity probe. The remarkable selectivity with which ESL-1 can be affinity-isolated is unexplained. Since ESL-1 is endogenously expressed in Chinese hamster ovary (CHO) cells in a non-E-selectin binding form, which can become activated upon transfection of a fucosyltransferase (FucT), we analyzed various CHO cell clones, each overexpressing one of seven different fucosyltransferases, by affinity isolation experiments with E-selectin-IgG. Two of the cell lines were the regulatory CHO mutants LEC11 and LEC12, each overexpressing a different hamster FucT, while the five other clones were stably transfected with human FucTIII to -VII. A large panel of glycoproteins was affinity-isolated with E-selectin-IgG from LEC11 cells and FucTIII transfectants, demonstrating that many different glycoproteins can acquire ligand activity upon alpha(1,3)-fucosylation. In contrast, ESL-1 was almost exclusively isolated as the dominant glycoprotein ligand from LEC12 cells as well as from FucTIV and FucTVII transfectants and less selectively from FucTV and FucTVI transfectants. The selective generation of ligand activity correlated with the selective generation of the HECA452-reactive carbohydrate epitope, which is known to bind to E-selectin. These data suggest that, dependent on the type of fucosyltransferase, ESL-1 is a strongly preferred target molecule for the generation of E-selectin-binding carbohydrate modifications.