Interleukin 15 (IL-15) is a widely expressed pro-inflammatory cytokine related to IL-2. IL-15 promotes activation of T cells, neutrophils and macrophages and is critical to dendritic cell function in several model systems. IL-15 has been shown to play a role in several inflammatory disorders, including rheumatoid arthritis, psoriasis and pulmonary inflammatory diseases. Emerging data suggest that IL-15 may serve as a good therapeutic target, as there appears to be a beneficial effect of IL-15 neutralization in models of psoriasis and diabetes. IL-15 shows activity on cells. Recombinant IL-15 is a non-glycosylated Protein, containing 115 amino acids, with a molecular weight of 13.3 kDa.