C-C Motif Chemokine 11 (CCL11) is a secreted protein that belongs to the intercrine beta (chemokine CC) family. In response to the presence of allergens, CCL11 selectively recruits eosinophils, a prominent feature of allergic inflammatory reactions. The effects of CCL11 are mediated by its binding to a G-protein-linked receptor known as a chemokine receptor. Chemokine receptors for CCL11 include CCR2, CCR3 and CCR5. However, it has been found that CCL11 has high degree selectivity for its receptor, such that they are inactive on neutrophils and monocytes, which do not express CCR3.