CsCXCe1: A novel Cynoglossus semilaevis CXC chemokine that functions as a chemoattractant and an immunomodulator for peripheral blood leukocytes

► CsCXCe1 is phylogenetically distantly related to all known CXC chemokines. ► CsCXCe1 expression was high in immune organs and activated by pathogen infection. ► rCsCXCe1 was chemotactic for the lymphocytes in the PBL of tongue sole and turbot. ► Mutation of the two Cys residues in the CXC motif abolished the activity of rCsCXCe1. ► rCsCXCe1 enhanced the activation and immune response of PBL.