Fig. 2

Components of the chemokine systems. The majority of chemokines can bind a series of cognate receptors, and a single receptor can bind multiple chemokines, as exhibited in this paradigm for most CC (blue) and CXC (dark blue) chemokines. Atypical receptors (green) can also interact with numerous chemokines. On the contrary, a minority of receptors (red) has only one ligand