The present invention relates to a polypeptide comprising at least four domains specifically binding to a certain MHC peptide complex, said domains separated by linker amino acid sequences, thereby providing each domain with the capability to bind a separate MHC peptide complex, to a nucleic acid encoding for such a polypeptide, to a vector comprising such a nucleic acid, to a host cell for expression of such a polypeptide, to a pharmaceutical composition comprising such a polypeptide, and to a kit of parts comprising at least two polypeptides according to the invention.
