|IL-7 participates in human T cell development and homeostatic proliferation, generation of CD4+ and CD8+ memory T cells and regulation of V(D)J recombination at the TCR gamma, TCR beta, and immunoglobulin heavy chain loci . IL-7 produced by stromal cells of the fetal liver, bone marrow, spleen and thymus functions during B cell development. IL-7 is essential for mouse B cell development.
NeoImmuneTech are developing a stabilised IL-7 Fc fusion protein as a long-acting T cell amplifier, for immunooncology-enabling potential. Called Hyleukin-7TM (research code NT-I7), this agent is engineered to induce a persistent and long-lasting anti-tumour T cell response. It acts at multiple levels of T cell development and enhances T cell production, maturation, expansion, and survival, and also improves T cell homing and tumour infiltration. The Fc portion of the fusion protein extends the protein's half-life, and is IgD and IgG4-based so does not induce ADCC or CDC reactions. Hyleukin-7 has advanced to early stage clinical trials in advanced cancers; for example, in combination with chemoradiotherapy (in glioma) and checkpoint inhibitors (in melanoma and triple negative breast cancer). Preclinical investigations are ongoing as a monotherapy, and as a combination strategy in additional cancer types and immunology-focused indications. Click here to link to ClinicalTrials.gov's full list of Hyleukin-7 trials. Both the EMA and FDA have granted orphan drug designation status to Hyleukin-7 (designated as rhIL-7-hyFc) as a treatment for idiopathic CD4+ lymphocytopenia (in 2017  and 2019  respectively).