CCR3 is a 0 chcmokine receptor, closely related to CCR1, CCR2, and CCR5. CCR3 is the principal chemokine receptor on eosinophils that mediates their migration to a variety of chemokines. including eotaxin, eotaxin 2, RANTES, MCP-2, MCP-3, and MCP-4. CCR3 is also expressed by other allergic leukocytes such as basophils, mast cells, and TH2 cells. Blocking CCR3 or CCR3 ligands has proven to be effective in animal models of asthma, for reducing inflammation and bronchohyperreactivity. For these reasons CCR3 is one of the promising targets for drug development for allergic disease.