Human eotaxin (Eot) is an 8.4 kDa, 74 amino acid (aa) residue polypeptide that is produced by a number of normal cells and cell lines.3, 4 Molecules in this group are characterized by the presence of four cysteines, the first two of which are immediately adjacent. To date, human members of this group include MCP-1, MCP-2, MCP-3, MIP-1 alpha, MIP-1 beta, RANTES and I-309,8 and Eot.

Eot activity is limited to eosinophils. For eosinophils, Eot has been proposed to be both an activator and chemoattractor. As an activator, Eot initiates actin polymerization intracellularly, an event that is a prerequisite to chemotaxis, and induces the production of reactive oxygen species, thereby playing a role as a mediator of inflammation.19, 20 It appears then that Eot alone has the ability to selectively prime eosinophils for chemotaxis, to direct their migration/chemotaxis, and to activate inflammatory activity in the cells attracted.