Selecta Biosciences, Inc. and Cyrus Biotechnology, Inc. announced a protein engineering collaboration combining Selecta’s ImmTOR platform with Cyrus’ ability to radically redesign protein therapeutics. The lead program in the collaboration is a proprietary interleukin-2 (IL-2) protein agonist designed to selectively promote expansion of regulatory T cells (Treg) for the treatment of patients with autoimmune diseases and other deleterious immune conditions. Novel IL-2 approaches and technologies are driving innovation in the therapeutic development space. The IL-2 pathway influences critical aspects of both immune stimulation and immune regulation, through the development and expansion of regulatory T cells (Treg). These Treg cells are a specialized subpopulation of T cells involved in suppressing certain immune responses and maintaining the body’s self-tolerance. Reductions in the number of Treg cells have been shown to drive a spectrum of autoimmune diseases and conversely, increasing Treg expansion may have clinical utility in reducing inflammation and improving disease outcomes. Early preclinical data investigating the effects of ImmTOR in combination with a Treg-selective IL-2 mutant protein (IL-2 “mutein”) demonstrate substantial synergistic activity in increasing the percentage and durability of Treg expansion in the spleen. This supports the potential of ImmTOR in combination with IL-2 proteins to restore immunotolerance to autoantigens and forms the basis for this partnership. Although IL-2 has been an attractive target for autoimmune indications, overcoming its immunostimulatory activities, short half-life and anti-IL-2 antibody formation has been challenging. Building on recent advancements in the field, its strong preliminary data suggest that ImmTOR in combination with Cyrus’ novel IL-2 protein agonist has the potential to unlock the value of this target and drive the development of a next generation, best-in-class asset.