Engineered orthogonal interleukin-9 receptor (oIL-9R)

The engineered orthogonal interleukin-9 receptor (oIL-9R) is a synthetic signaling platform designed to enhance the efficacy and safety of adoptive cell therapies (ACT). It consists of a modified interleukin-9 receptor alpha chain that has been engineered to bind exclusively to a specific, non-natural (orthogonal) IL-9 ligand, such as STK-009, while remaining unresponsive to endogenous wild-type IL-9 (Kalbasi et al., 2022, Nature). This system allows for the selective stimulation of engineered T cells, such as pmel-1 T cells, directly within the patient, bypassing the systemic toxicities often associated with high-dose cytokine administration. Upon ligand binding, the oIL-9R activates the JAK/STAT signaling pathway, specifically STAT1, STAT3, and STAT5, which are critical for T cell expansion, survival, and the development of a polyfunctional effector phenotype. Preclinical studies have shown that this "remote control" of T cells can lead to the complete eradication of solid tumors that are otherwise resistant to immunotherapy. The oIL-9R technology is currently being explored as a way to improve the persistence and potency of various therapeutic cell products, including TCR-T and CAR-T cells, in the treatment of advanced malignancies (Synthekine, 2024).

Other names

Orthogonal IL-9 receptoroIL-9RSynthetic IL-9 receptorEngineered orthogonal IL-9 receptor on pmel-1 T cells

The engineered orthogonal interleukin-9 receptor (oIL-9R) selectively binds to a matched orthogonal IL-9 ligand (e.g., STK-009). This binding induces receptor dimerization and activates the Janus kinase (JAK) proteins JAK1 and JAK3, which are associated with the receptor's cytoplasmic tails. These kinases then phosphorylate the receptor and recruit STAT proteins (STAT1, STAT3, and STAT5), which translocate to the nucleus to drive the expression of genes involved in T cell proliferation, survival, and effector function specifically within the engineered cell population (Kalbasi et al., 2022, Nature).