The present invention generally relates to fusion proteins of immunoglobulins and interleukin-2 (IL-2). More particularly, the invention concerns fusion proteins of immunoglobulins and mutant IL-2 that exhibit improved properties for use as therapeutic agents, e.g. in the treatment of autoimmune diseases and immune-mediated inflammatory diseases. In addition, the present invention relates to polynucleotides encoding such fusion proteins, and vectors and host cells comprising such polynucleotides. The invention further relates to methods for producing the fusion proteins of the invention, and to methods of using them in the treatment of disease.