Chemokine receptors divide the labor of inflammatory infiltration. A monocyte engaged in selectin-mediated rolling on vascular endothelial cells is depicted as expressing CXCR2 (red) and CCR2 (green). First, interaction of CXCR2 with its ligand IL-8 (red dots attached to glycosaminoglycans (GAG)) leads to up-regulation of α4β1 integrin affinity and firm adhesion. Then, interaction of CCR2 with its ligand MCP-1 (green dots attached to GAG) leads to migratory behavior i.e., diapedesis and entry into the subendothelium. Here, chemokines are shown as being presented to cells in the vascular lumen in the context of endothelial cell surface GAGs.