FIG. 1.

Binding of mCD33-Fc to BSM: effect of 9-O-acetylation and side chain modification of sialic acid. Biotinylated BSM was treated with base or with CHE-Fc to remove 9-O-acetyl esters from its sialic acids. ELISA was used to assay the interaction between mCD33-Fc and BSM as described in Materials and Methods. In some instances, the BSM was also treated with mild periodate to truncate sialic acid side chains. The mean A₄₀₅ values of triplicate wells are plotted for each sample. The error bars indicate standard deviations.