Definition

An interleukin-2 (IL-2) and interleukin-15 (IL-15) receptor agonist with high binding affinity for the common heterodimeric receptor IL-2Rbeta-gamma, which is composed of the IL-2 receptor subunit beta (IL-2Rbeta; CD122) and IL-2 receptor subunit gamma (IL-2Rgamma; common gamma; CD132), and no binding affinity for the IL-2 receptor subunit alpha (IL-2Ralpha; CD25), with potential immunoregulatory and antineoplastic activities. Upon administration, IL-2/IL-15 receptor agonist NL-201 targets and binds to IL-2Rbeta-gamma on natural killer (NK) and T cells and activates IL-2Rbeta-gamma-mediated signaling. This induces the selective proliferation of CD8+ T cells and NK cells, enhances tumor cell killing and decreases tumor cell proliferation. NL-201 does not bind to IL-2Ralpha, thereby circumventing both the activation of immunosuppressive regulatory T cells (Tregs) and the exacerbation of vascular leak syndrome associated with recombinant human IL-2. IL-2 and IL-15 receptors are cytokine receptors that play key roles in the immune response.