Figure 5.

Effect of HSA on mAb binding to antigen measured by BLI is ionic-strength dependent and mAb-specific. Binding of mAb1 (black) and mAb2 (red) to biotinylated antigen in the presence of increasing HSA concentrations was observed by biolayer interferometry at 10 (panel a) and 137 (panel b) mM NaCl. The normalized response (to binding at 0.1 g/L HSA) is shown as a function of HSA concentration. The dotted line indicates the normal at 1.0, in order to illustrate the relationship of the data points to this line. A minimum of 0.1 g/L HSA is required to prevent non-specific binding to the biosensor tip. Experiments were performed in triplicate, and the mean value and standard deviation are shown. One-way ANOVA was performed at each HSA concentration and p-values <0.05 are indicated with an asterisk. All data are summarized in Tables S2–4.