A burgeoning family of biological mediators: chemokines and chemokine receptors.

Chemokines are a superfamily of pro-inflammatory polypeptide cytokines that selectively attract and activate different cell types. Most of its members are small proteins that exhibit conserved cysteines in specific positions. Chemokines activate cells through their binding to shared or unique cell surface receptors which belong to the seven-transmembrane (STM), G-protein-coupled receptors (GPCRs). The large number of chemokines and chemokine receptors are indicative of the importance of these molecules in a variety of pathophysiological conditions.