Disclosed herein are immunoglobulin fusion proteins comprising a first antibody region, a first therapeutic agent, and a first connecting peptide； wherein the first therapeutic agent is attached to the first antibody region by the connecting peptide； and wherein the connecting peptide does not comprise a region having beta strand secondary structure. The connecting peptide may comprise an extender peptide. The extender peptide may have an alpha helical secondary structure. The connecting peptide may comprise a linker peptide. The linker peptide may not comprise any secondary structure. Also disclosed herein are compositions comprising the immunoglobulin fusion proteins and methods for using the immunoglobulin fusion proteins for the treatment or prevention of a disease or condition in a subject.
