Regulation of the chemokine system at the level of chemokine receptor expression and signaling activity

The chemokine system is highly influenced by the microenvironmental context. Regulation of the chemokine system occurs not only at the level of agonist production, but also at the level of chemokine receptor expression. This review provides examples of regulation of the system at the receptor level by modulation of receptor expression in canonical cellular targets (tuning of the system), and induction of novel receptors (shaping of the system), with particular attention to dendritic cells as a cellular model. Receptor signaling activity represents a further potential level of regulation of the system. Finally chemokines can also influence the microenvironment by modulating gene expression in target cells.