Swine CXCL13 (C-X-C motif chemokine ligand 13), also known as BCA-1 (B-cell–attracting chemokine 1), is a homeostatic chemokine belonging to the CXC chemokine family that plays a central role in B-cell migration and lymphoid tissue organization. In pigs (Sus scrofa), CXCL13 is produced primarily by follicular dendritic cells, stromal cells, and macrophages within secondary lymphoid organs, including the lymph nodes, spleen, and mucosal-associated lymphoid tissues. CXCL13 signals through the chemokine receptor CXCR5, which is expressed on B lymphocytes and T follicular helper (Tfh) cells, guiding their migration into lymphoid follicles and germinal centers where B cells proliferate, undergo affinity maturation, and differentiate into antibody-producing plasma cells. In swine immunity, CXCL13 plays an important role in germinal center formation, B-cell homing, and development of humoral immune responses during infection or vaccination. Because pigs share important anatomical and immunological similarities with humans, they are used as translational animal models for infectious and mucosal immune responses, including studies of influenza virus and other respiratory pathogens, where CXCL13-mediated B-cell recruitment contributes to lymphoid follicle development and antibody responses in respiratory-associated lymphoid tissues.