Swine Interleukin-12 p70 (IL-12 p70) is a heterodimeric cytokine that plays a central role in regulating cell-mediated immune responses in pigs (Sus scrofa). IL-12 p70 is composed of two subunits, p35 and p40, and is produced primarily by activated antigen-presenting cells such as macrophages and dendritic cells in response to microbial infection or inflammatory stimuli. Swine IL-12 p70 binds to the IL-12 receptor complex expressed on natural killer (NK) cells and T lymphocytes, activating intracellular signaling through the JAK–STAT pathway, particularly STAT4, which promotes differentiation of naïve T cells into T helper 1 (Th1) cells. This signaling enhances production of interferon-γ (IFN-γ), increases cytotoxic activity of NK cells, and strengthens cell-mediated immunity against intracellular pathogens. In pigs, IL-12 p70 contributes to host defense against bacterial and viral infections, including important swine pathogens such as porcine reproductive and respiratory syndrome virus (PRRSV), Salmonella spp., and Mycoplasma hyopneumoniae. Due to its role in regulating Th1 immune responses, swine IL-12 p70 is widely studied in veterinary immunology and translational research, particularly in investigations of host–pathogen interactions, vaccine development, and immune modulation relevant to swine health and comparative biomedical research.