Figure 8. A schematic showing processes involved in neutrophil recruitment in lung tissue.

CXCL8 produced at the site of insult migrates to the bloodstream where they form a concentration gradient, made up of monomers and dimers in solution, and monomers and dimers bound to GAGs. Free and GAG-bound monomers and dimers exist in equilibrium, and each species can bind and activate cognate receptors on neutrophils. Local concentrations and gradients dictate the spatial and temporal predominance of each species, which in turn modulates overall recruitment.