ALT-803 is an IL-15 superagonist developed to promote immune activation. It is being investigated as an immuno-oncology agent, as immunotherapy post-allogeneic transplantation for hematological malignancies, and as an HIV therapy.
ALT-803 is produced from a high-yield recombinant mammalian cell line which co-expresses an IL-15 activation mutant, IL-15N72D and IL-15Rαsushi domain/Fc fusion protein as a stable soluble complex. The sushi domain increases transpresentation of the ALT-803 complex to the IL-2β/γ dimer which is the signal transducing component of the IL-15 receptor. The IgG Fc domain increases in vivo
half-life.Image re-produced from Altor BioScience Corporation's ALT-803 fact sheet (download the pdf here)