Swine Interleukin-8 (IL-8), also known as CXCL8, is a potent pro-inflammatory chemokine that plays a central role in innate immune responses in pigs (Sus scrofa domesticus) by mediating neutrophil chemotaxis, activation, and migration to sites of infection or tissue injury. Produced by macrophages, respiratory and intestinal epithelial cells, endothelial cells, and other immune cells in response to microbial products and inflammatory cytokines, swine IL-8 signals primarily through CXCR1 and CXCR2 receptors to promote rapid neutrophil recruitment and amplification of inflammatory responses. Elevated IL-8 expression is observed in economically significant diseases such as porcine reproductive and respiratory syndrome (PRRS), swine influenza, Mycoplasma hyopneumoniae infection, Actinobacillus pleuropneumoniae pneumonia, enteric infections, and bacterial sepsis, where excessive neutrophilic inflammation can contribute to lung injury, reduced growth performance, and systemic pathology. As a biomarker, IL-8 is widely used to assess immune activation, vaccine response, and disease severity in swine production systems. In translational research, pigs serve as valuable large-animal models for human respiratory disease, sepsis, trauma, and inflammatory disorders due to their physiological and immunological similarities to humans; thus, characterization of swine IL-8 supports studies of neutrophil-driven immunopathology, cytokine network regulation, and development of targeted anti-inflammatory and immunomodulatory therapies relevant to both veterinary and human medicine.