Ferret CCL17 (C-C motif chemokine ligand 17), also known as thymus and activation-regulated chemokine (TARC), is a member of the CC chemokine family that regulates Th2-associated immune responses in ferrets (Mustela putorius furo). CCL17 is produced primarily by dendritic cells, macrophages, endothelial cells, and epithelial cells in response to inflammatory and type 2–associated cytokines. It functions predominantly through the CCR4 receptor to promote chemotaxis and activation of Th2 lymphocytes and regulatory T cells, contributing to adaptive immune polarization and modulation of inflammatory responses. In healthy ferrets, basal CCL17 expression is generally low, but levels may increase during allergic-type inflammation, respiratory viral infection, parasitic challenge, or experimental immune stimulation. In biomedical and translational research, ferret CCL17 is of particular interest in respiratory disease models—including influenza and SARS-CoV-2—where characterization of Th2 versus Th1 immune balance and T cell recruitment is important for understanding disease pathogenesis and vaccine responses.