Characterisation of the biological activity of recombinant equine eotaxin in vitro

The chemokine eotaxin (CCL11) is a key player in the trafficking of eosinophils to normal tissues and in the tissue eosinophilia associated with human allergic disease. We have recently cloned equine eotaxin and here we report the production of rEq eotaxin, with and without a C-terminal fusion peptide, in a novel expression system utilising stably transfected insect cells. rEq eotaxin induced equine eosinophil migration and superoxide production in vitro. A shape change in human eosinophils that could be blocked by 7B11, a monoclonal antibody against human CCR3, was also observed. Biological activity was not dependent on an intact eotaxin C-terminus. These results suggest that equine eotaxin, like its human ortholog, may play a role in eosinophil accumulation and activation in the horse.