Swine CCL25 (C-C motif chemokine ligand 25, also known as TECK – thymus-expressed chemokine) is a homeostatic chemokine that plays a key role in regulation of lymphocyte trafficking and mucosal immune responses in pigs (Sus scrofa domesticus). CCL25 primarily signals through the CCR9 receptor, directing migration of T lymphocytes, particularly gut-homing T cells, to intestinal tissues. In swine, CCL25 is highly expressed in the small intestine and thymus, where it contributes to development and positioning of T cells within mucosal immune compartments and supports immune surveillance at the intestinal barrier. CCL25-mediated CCR9 signaling is important for recruitment of lymphocytes to the gut-associated lymphoid tissue (GALT), facilitating immune responses against enteric pathogens and maintaining intestinal immune homeostasis. In swine health, CCL25 is particularly relevant in enteric infections caused by pathogens such as porcine epidemic diarrhea virus (PEDV), transmissible gastroenteritis virus (TGEV), and enterotoxigenic Escherichia coli, where gut-directed immune cell trafficking is critical for mucosal defense and pathogen clearance. Dysregulation of CCL25 expression may influence intestinal inflammation or impaired mucosal immunity. Because pigs are widely used as large-animal models for human gastrointestinal physiology and mucosal immunology, characterization of swine CCL25 supports studies of gut immune cell migration, host–pathogen interactions, and development of mucosal vaccines and therapies relevant to both veterinary and human medicine.