Disulfide-linked multivalent MHC class I comprising multi-function proteins

A disulfide-linked multivalent multi-function protein, comprising:

• two antigen presenting domains,
• one antibody Fc-region, and
• one or more antigen binding sites,
• wherein the antigen presenting domain comprises in an N- to C-terminal direction either:
• (i) a T-cell response eliciting peptide,
• (ii) a β2-microglobulin, and
• (iii) extracellular domains α1, α2, and α3 of a class I MHC molecule with a relative frequency of 1% or more,
• or
• (i) a T-cell response eliciting peptide,
• (ii) extracellular domains α1, α2, and α3 of a class I MHC molecule with a relative frequency of 1% or more, and
• (iii) a β2-microglobulin,
• wherein the antigen binding site binds to a cancer cell surface antigen, and
• wherein the antigen presenting domain has at least two non-naturally occurring cysteine residues that form an intrachain/interdomain disulfide bond, wherein one non-naturally occurring cysteine residue in the antigen presenting domain is in a linker between the T-cell response eliciting peptide and either the β2-microglobulin or the α1 domain of the class I MHC molecule, and the other non-naturally occurring cysteine residue is in one of the extracellular domains α1, α2, and α3 of the class I MHC molecule and wherein the at least two non-naturally occuring cysteine residues are at position 11 and at position 227 or at position 11 and at position 108.