The IL-15 protein is a key cytokine that promotes inflammatory and protective immune responses against invaders by regulating immune cells in the innate and adaptive systems. It stimulates natural killer cells, T cells and B cells, and promotes the secretion of various cytokines. Animal-Free IL-15 Protein, Pig (His) is the recombinant pig-derived animal-FreeIL-15 protein, expressed by E. coli , with N-His labeled tag. This product is for cell culture use only.