Figure 6. Human OPN‐mediated monocyte phagocytosis is isoform and RGD independent .

After 30 min pretreatment with polymixin‐B (PMB), primary human monocytes were treated for 2 h with recombinant OPN proteins or vehicle (PMB) in the presence of fluorescently conjugated Escherichia coli particles. Cells were washed, and cellular fluorescence of non‐viable cells was quenched with Trypan Blue. Phagocytosis is presented as the fold increase in fluorescence from viable cells relative to vehicle control cells (PMB). All conditions were normalized for background fluorescence (E. coli particles only) before calculation of the fold change relative to vehicle control. A, phagocytosis induced by 0.5 μg ml⁻¹ OPN spliced isoforms relative to vehicle (PMB). B, phagocytosis induced by 1.0 μg ml⁻¹ OPN‐a‐RGD and OPN‐a‐KAE. All samples were run in replicates of n = 5, according to the manufacturer's instructions (Vybrant Phagocytosis Assay Kit; Life Technologies). Significance is presented relative to the vehicle control.