Study of the carbohydrate specificity of the transmembrane receptor DC-SIGN: features of recognition of antigenic factors 34 and 13b of yeast fungi

Abstract

The transmembrane protein DC-SIGN, which is a pattern recognition receptor (PRR), plays an important role in the development of antifungal immunity. It was previously shown that the pentamannoside Man-α-(1→2)-Man-α-(1→3)-Man-α-(1→2)-Man-α-(1→2)-Man-α, corresponding to yeast fungal antigenic factor 13b, is a high-affinity ligand of DC-SIGN. However, the influence of the location of α-(1→3)-linkage within the pentasaccharide chain on the binding efficiency to DC-SIGN has not been studied yet. Herein, we report the synthesis of penta- and hexasaccharides corresponding to antigenic factor 34. The compounds obtained are structurally related to the high-affinity ligand of DC-SIGN described above, but contain an α-(1→3)-linkage at the non-reducing end of the carbohydrate sequence. Biotinylated derivatives of the synthesized oligosaccharides along with previously synthesized oligosaccharide ligands were used to determine the recognition efficiency of DC-SIGN, and the fundamental importance of localizing the α-(1→3)-linkage inside the chain, but not at its end was shown. The obtained results are critically important for the development of vectors for targeting dendritic cells and further interdisciplinary studies of DC-SIGN.