Lewis epitopes are key elements involved in the leukocyte homing and extravasation process and thus are important for lymphocyte maturation and natural defense functions. Fucose-containing glycans also play critical roles in cell signaling and development (1). More than 10 fucosyltransferases have been cloned (2). FUT1 and FUT2 are alpha 1-2 fucosyltransferases and are responsible for ABO blood-group antigen synthesis. FUT8 is an alpha 1-6 fucosyltransferase that adds a fucose to the chitobiose core of N-glycans (3). FUT3, FUT4, FUT5, FUT6, FUT7 and FUT9 are alpha 1-3 or alpha 1-4 fucosyltransferases and are responsible for Lewis antigen generation.
FUT7 plays an exclusive role for the biosynthesis of sialy Lewis X (sLeX) epitope (NeuAc alpha 2,3Gal beta 1,4 [Fuc alpha 1,3] GlcNAc) that serves as a ligand in the E-selectin and P-selectin mediated adhesion of leukocytes to activated endothelium or platelets, and it is critical for the extravasation of immune cells (4, 5, 6). The activity of this enzyme has been measured with a phosphatase-coupled method (7).
R&D Systems Recombinant Human FUT7 has been used for the cell surface glycoengineering of several cell types. In both B cells and mesenchymal stem cells, FUT7 generated, cell surface sLeX leads to enhanced engagement with E-Selectin ligands (8, 9). In naïve regulatory T cells (Treg), engineered sLeX promotes homing to areas of inflammation in vivo (10). These studies suggest that FUT7-mediated generation of sLeX has potential to increase the efficacy of cellular-based therapeutics by enhanced targeting of cells to areas of pathology.