Described is a polypeptide comprising at least four domains specifically binding to a certain MHC peptide complex, the 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 molecule encoding such a polypeptide, to a vector comprising such a nucleic acid molecule, 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 of the disclosure.