The present invention concerns a structurally distinct immunosuppressive mimic of TGF-β that is a potent inducer of murine and human regulatory T cells and provides a therapeutic agent for the treatment of inflammatory disorders. Disclosed herein is a novel parasite TGF-β mimic which fully replicates the biological and functional properties of TGF-β, including binding to mammalian TGF-β receptors and inducing Foxp3+ Treg in both murine and human CD4+ T cells. This TGF-β mimic shares no homology to mammalian TGF-β or other members of the TGF-β family, but s distinctly related to the component control protein (CCP) superfamily.