The immune system is composed of single cells, and its function is entirely dependent on the
capacity of these cells to traffic, localize within tissues, and interact with each other in a
precisely coordinated fashion. There is growing evidence that the large families of
chemokines and chemokine receptors provide a flexible code for regulating cell traffic and
positioning in both homeostatic and inflammatory conditions. The regulation of chemokine
receptor expression during development and following cell activation explains the complex …