Above a ligand concentration of 156 µM, the L-SIGN binding response is close to 0, compared with over 2000 RU for the same concentration to inhibit DC-SIGN interaction. The addition of a guanidium group on the triazole moiety (Man84 compound) resulted in enhancement of inhibitory potential towards L-SIGN (IC50 = 23,9 µM) by a factor of 81 relative to mannose (IC50=1.94 mM) , but only by a factor of 3 towards DC-SIGN (IC50 = 1,06 mM vs IC50=3mM for mannose) . Thus, Man84 shows a binding affinity towards L-SIGN with a ratio of more than 40 times the one of DC-SIGN. Such an IC50, in the low micromolar, for a monovalent glycomimetic is the best reported to date for a C-type lectin target. These data also indicate that guanidinium enable the creation of interactions in L-SIGN that would not be effective in DC-SIGN and thus using a different binding mode that Man79.