Abstract: The present invention relates to polypeptides which share primary sequence with human Interleukin 2 (IL-2), except for several amino acids that have been mutated. One panel of IL-2 variants comprise mutations with impressive manufacturability that preferentially promotes the proliferation, survival, activation and/or function of immunosuppressive regulatory T cells (Tregs) (Treg: CD4+CD25+FoxP3+) over effector T cells and Natural Killer Cells (NK). cells. Also includes therapeutic uses of such IL-2 selective agent, used alone, or in combination with immune modulating agents or disease-tissue targeting antibody, protein or peptide to treat Treg cell-deficiency, various autoimmune and inflammatory disorders, organ transplantation and graft-versus-host disease. In another aspect the present invention relates to pharmaceutical compositions comprising the polypeptides disclosed.

Abstract: The present disclosure provides a cytokine-based bioactivatable drug construct (“VitoKine”) platform that aims to reduce systemic mechanism-based toxicities and lead to broader therapeutic utility for proteins and cytokines such as IL-15 and IL-2 for the treatment of cancer, autoimmune diseases, inflammatory diseases, viral infection, transplantation and various other disorders. The novel VitoKine constructs of the present invention comprise: 1) a tissue or disease site targeting moiety D1 domain (“D1”), 2) a bioactivatable moiety D2 domain (“D2”), and a concealing moiety D3 domain (“D3”). Importantly, because the “active moiety” of the VitoKine construct will remain inert until activated locally by proteases that are upregulated in diseased tissues, this will limit binding of the active moiety to the receptors or to the targets in the peripheral or on the cell-surface of non-diseased cells and tissue to prevent over-activation of the pathway and reduce undesirable “on-target” “off tissue” toxicities.