Definition

A human fusion protein consisting of the cytokine interleukin (IL)-15 and the high-affinity binding sushi+ domain of IL-15 receptor alpha (IL-15Ra), with potential antineoplastic activities. Upon administration, SOT101 activates and increases the levels of natural killer (NK) cells and memory CD8+ T cells. The memory T cells enhance the secretion of the cytokine interferon-gamma (IFN-g), which further potentiates the immune response against tumor cells. This may increase tumor cell killing and decrease tumor cell proliferation. IL-15 regulates CD8+ T- and NK-cell development, activation and proliferation. SOT101 is more potent than unmodified IL-15 and does not require endogenous IL-15Ra for its actions.