Figure 1

Development of anti-OPN antibody. A Amino acid sequence of OPNa (full length OPN). Truncated isoforms OPNb and OPNc are highlighted with blue and yellow, respectively. Binding sites for integrins are highlighted with green (RGD binding integrins) and orange (LDV binding integrins). Thrombin cleavage site is marked by a red arrow. B Characterization of AOM1 including its cross-reactivity, binding epitope, dissociation constant (K_D) for the Fab and its ability to inhibit binding of recombinant OPNa to immobilized integrin αvβ3 have been determined. C Selectivity of AOM1 for human OPN over other RGD-motif containing proteins was assessed by ELISA as detailed in Materials and Methods. RGD containing proteins were immobilized on an immunosorbent plate and binding of AOM1 assessed at 0.1, 1, 10 and 1000 nM concentrations. With the exception of 1000 nM AOM1 vs. ColA1, there was no binding observed at any concentration of AOM1 up to 1000 nM versus thrombospondin, vitronectin, ColA1 and fibronectin whilst saturated binding was observed vs. OPN at antibody concentrations as low as 0.1 nM AOM1. Each bar represents mean OD450 nm value of triplicate measurements with standard error bars.