Abstract: The present invention relates to chimeric proteins, to compositions comprising such proteins and to the medical uses of such proteins and compositions. In particular the proteins or compositions of the invention may be used in the prevention or treatment of autoimmune diseases or inflammatory diseases, or for the prevention or treatment of diseases mediated through binding of sialic acid dependent receptors, or as vaccines or as anti-cancer agents. One aspect of the invention relates to a chimeric Fc receptor binding protein which comprises two chimeric polypeptide chains, wherein each chimeric polypeptide chain comprises an immunoglobulin G heavy chain constant region, a tailpiece region and a hinge region, wherein the amino acid sequence of each polypeptide chain possess a sugar moiety at or close to the N-terminus and a sugar moiety at or close to the C-terminus, and their use in the treatment or prevention of a disease mediated by a pathogen that relies on sialic acid receptors interactions.

Abstract: A method for treatment of a mammalian subject for an autoimmune or inflammatory disease, the method comprising: administering to the mammalian subject an effective amount of a polymeric protein comprising five, six or seven polypeptide monomer units; wherein each polypeptide monomer unit comprises an Fc receptor binding portion comprising two immunoglobulin G heavy chain constant regions; wherein each immunoglobulin G heavy chain constant region comprises a cysteine residue which is linked via a disulfide bond to a cysteine residue of an immunoglobulin G heavy chain constant region of an adjacent polypeptide monomer unit; wherein the polymeric protein does not comprise a further immunomodulatory portion; or an antigen portion that causes antigen-specific immunosuppression when administered to the mammalian subject.

Abstract: A method for treatment of a mammalian subject for an autoimmune or inflammatory disease, the method comprising: administering to the mammalian subject an effective amount of a polymeric protein comprising five, six or seven polypeptide monomer units; wherein each polypeptide monomer unit comprises an Fc receptor binding portion comprising two immunoglobulin G heavy chain constant regions; wherein each immunoglobulin G heavy chain constant region comprises a cysteine residue which is linked via a disulfide bond to a cysteine residue of an immunoglobulin G heavy chain constant region of an adjacent polypeptide monomer unit; wherein the polymeric protein does not comprise a further immunomodulatory portion; or an antigen portion that causes antigen-specific immunosuppression when administered to the mammalian subject.

Abstract: A method for treatment of a mammalian subject for an autoimmune or inflammatory disease, the method comprising: administering to the mammalian subject an effective amount of a polymeric protein comprising five, six or seven polypeptide monomer units; wherein each polypeptide monomer unit comprises an Fc receptor binding portion comprising two immunoglobulin G heavy chain constant regions; wherein each immunoglobulin G heavy chain constant region comprises a cysteine residue which is linked via a disulfide bond to a cysteine residue of an immunoglobulin G heavy chain constant region of an adjacent polypeptide monomer unit; wherein the polymeric protein does not comprise a further immunomodulatory portion; or an antigen portion that causes antigen-specific immunosuppression when administered to the mammalian subject.