Guinea Pig Interleukin-15 (IL-15) is a cytokine that plays an important role in regulating innate and adaptive immune responses in guinea pigs (Cavia porcellus). IL-15 is produced by a variety of cell types, including monocytes, macrophages, dendritic cells, and epithelial cells, in response to infection or inflammatory stimuli. Guinea pig IL-15 signals through a receptor complex composed of IL-15Rα together with the shared IL-2/15Rβ (CD122) and common γ chain (γc), activating intracellular signaling pathways such as JAK–STAT that promote lymphocyte proliferation, survival, and activation. In guinea pigs, IL-15 is particularly important for the development, maintenance, and activation of natural killer (NK) cells and memory CD8⁺ T cells, supporting cytotoxic immune responses against infected cells. It also contributes to regulation of mucosal immunity and inflammatory responses during infection. In cell culture, recombinant guinea pig IL-15 is commonly used to stimulate proliferation and survival of NK cells and cytotoxic T lymphocytes, maintain memory CD8⁺ T cell populations, and enhance cytotoxic activity in in vitro immune assays. Guinea pig IL-15 is widely studied in infectious disease and translational research because guinea pigs serve as an important model for diseases such as tuberculosis, where IL-15–mediated activation of cytotoxic lymphocytes helps researchers investigate cellular immunity and evaluate vaccines and immunotherapies relevant to human disease.