Fig. 5.
SPR measurement of the affinity of antibody to I domains and inhibition of I domain-ligand interactions. (A) Antibodies were immobilized to a Biacore chip, and the I domains were injected at a series of two-fold serial dilutions starting from 12.5 nM in buffer containing either 10 mM MgCl2 or 1 mM EDTA. (B) The I domains at 200 nM were preincubated with the antibodies, ranging from 62.5 to 1000 nM, and this complex was injected into a chip coated with Mac-1 ligands. The solid lines represent the best fit of the model to the data, from which the values of a half maximal inhibitory concentration (IC50) of antibodies were derived.