CCL11 is a small cytokine belonging to the CC chemokine family. CCL11 selectively recruits eosinophils by inducing their chemotaxis, and therefore, is implicated in allergic responses. The effects of CCL11 are mediated by its binding to a G-protein-linked receptor known as a chemokine receptor. Chemokine receptors for which CCL11 is a ligand include CCR2,CCR3 and CCR5. However, it has been found that eotaxin-1 (CCL11) has high degree selectivity for its receptor, such that they are inactive on neutrophils and monocytes, which do not express CCR3.