CCL11 is a potent eosinophil chemoattractant that was originally purified from bronchoalveolar lavage fluid of guinea pigs sensitized by aerosol challenge with ovalbumin. CCL11 also shows high aa sequence identity to members of the MCP family. CCL11 is chemotactic for eosinophils, but not mononuclear cells or neutrophils. CCL11 mRNA is expressed in a variety of tissues. The expression of CCL11 mRNA is induced in cultured endothelial cells in response to IFN-gamma. In addition, CCL11 mRNA is also induced in response to the transplantation of IL-4-secreting tumor cells. The CC chemokine receptor 3 (CCR3) has been identified as a specific human CCL11 receptor.