Polypeptide monomers and dimers containing mutated ilt

A polypeptide comprising an ILT-like segment and an Fc-like segment wherein either

• (a) the ILT-like segment is the N-terminal segment of the polypeptide and has at least a 45% identity and/or 55% similarity to SEQ ID NO:
• 19;
• and said N-terminal segment per se has the property of (i) binding to a given Class I pMHC with a KD of less than or equal to 1 μM and/or with an off-rate (koff) of 2 S−1 or slower, and (ii) inhibiting CD8 binding to the given pMHC to a greater extent than the polypeptide SEQ ID NO:
• 3;
• and the Fc-like segment is the C-terminal segment of the polypeptide and comprises a portion of the constant domain of one of the heavy chains of an immunoglobulin having at least 70% identity and/or 80% similarity to the corresponding portion of SEQ ID NO 139;
• or
• (b) the Fc-like segment is the N-terminal segment of the polypeptide and comprises a portion of the constant domain of one of the heavy chains of an immunoglobulin having at least 70% identity and/or 80% similarity to the corresponding portion of SEQ ID 139;
• and the ILT-like segment is the C-terminal segment of the polypeptide and has at least a 45% identity and/or 55% similarity to SEQ ID NO:
• 19;
• and said C-terminal segment per se has the property of (i) binding to a given Class I pMHC with a KD of less than or equal to 1 μM and/or with an off-rate (koff) of 2 S−1 or slower, and (ii) inhibiting CD8 binding to the given pMHC to a greater extent than the polypeptide SEQ ID NO:
• 3,
• wherein the polypeptide is arranged as a monomeric polypeptide or as a polypeptide dimer comprising a first polypeptide and a second polypeptide, in which dimer
• (i) the first and/or the second polypeptide comprises an ILT-like segment having at least a 45% identity and/or 55% similarity to SEQ ID NO:
• 19;
• (ii) said ILT-like segment(s) per se have the property of (a) binding to a given Class I pMHC with a KD of less than or equal to 1 μM and/or with an off-rate (kOff) of 2 S−1 or slower, and (b) inhibiting CD8 binding to the given pMHC to a greater extent than the polypeptide SEQ ID NO:
• 3;
• (iii) each of the first and second polypeptides comprises an Fc-like segment comprising a portion of the constant domain of one of the heavy chains of an immunoglobulin having at least 70% identity and/or 80% similarity to the corresponding portion of SEQ ID NO:
• 139;
• and wherein either (a) the ILT-like segment(s) is/are the N-terminal segment(s) of the first and/or second polypeptides, and the Fc-like segments are the C-terminal segments of the first and second polypeptides or (b) the Fc-like segments are the N-terminal segments of the first and/or second polypeptides, and the ILT-like segment(s) is/are the C-terminal segment(s) of the first and second polypeptides.