Polypeptide useful in adoptive cell therapy

Abstract

The present invention provides a polypeptide having the formula: St-R1-S1-Q-S2-R2 wherein St is a stalk sequence which, when the polypeptide is expressed at the surface of a target cell, causes the R and Q epitopes to be projected from the cell surface; R1 and R2 are a Rituximab-binding epitopes each having the an amino acid sequence selected from the group consisting of SEQ ID No. 1, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 and 16 or a variant thereof which retains Rituximab-binding activity; S1 and S2 are optional spacer sequences, which may be the same or different; and Q is a QBEnd10-binding epitope having the amino acid sequence shown as SEQ ID No. 2 or a variant thereof which QBEnd10-binding activity. The invention also provides a nucleic acid sequence encoding such a polypeptide and uses thereof in adoptive cell transfer.

1 . A polypeptide having the formula:
   St-R1-S1-Q-S2-R2   wherein   St is a stalk sequence which, when the polypeptide is expressed at the surface of a target cell, causes the R and Q epitopes to be projected from the cell surface;   R1 and R2 are a Rituximab-binding epitopes each having the an amino acid sequence selected from the group consisting of SEQ ID NO: 1, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 and 16 or a variant thereof which retains Rituximab-binding activity;   S1 and S2 are optional spacer sequences, which may be the same or different;   Q is a QBEnd10-binding epitope having the amino acid sequence shown as SEQ ID NO: 2 or a variant thereof which QBEnd10-binding activity; and   wherein the distance between R1 and R2 is too long for the polypeptide to bind both antigen binding sites of Rituximab simultaneously.   
     
     
         2 . (canceled) 
     
     
         3 . The polypeptide according to  claim 1 , wherein the spacer sequences S1 and S2 have a combined length of at least about 10 amino acids. 
     
     
         4 . The polypeptide according to  claim 1 , wherein the distance between R1 and R2 is more than 76.57 Å. 
     
     
         5 . The polypeptide according to  claim 1 , wherein the stalk sequence is derivable from CD8alpha. 
     
     
         6 . The polypeptide according to  claim 5 , wherein the stalk sequence comprises the amino acid sequence shown as SEQ ID NO: 3. 
     
     
         7 . The polypeptide according to  claim 1  which comprises the sequence shown as SEQ ID NO: 4, or a variant thereof which has at least 80% identity with the sequence shown as SEQ ID NO: 4 and which (i) binds QBEND10; (ii) binds Rituximab and (iii) when expressed on the surface of a cell, induces complement-mediated killing of the cell in the presence of Rituximab. 
     
     
         8 . A fusion protein which comprises the polypeptide according to  claim 1  fused to a protein of interest (POI). 
     
     
         9 . The fusion protein according to  claim 8 , wherein the POI is a chimeric antigen receptor (CAR) or a T cell receptor (TCR). 
     
     
         10 . The fusion protein according to  claim 8  which comprises a self-cleaving peptide between the polypeptide and the protein of interest. 
     
     
         11 . (canceled) 
     
     
         12 . A vector which comprises a nucleic acid sequence comprising a nucleotide sequence that encodes the polypeptide according to  claim 1  or encodes a fusion protein that comprises said polypeptide fused to a protein of interest (POI). 
     
     
         13 . The vector according to  claim 12 , which further comprises a transgene of interest. 
     
     
         14 . The vector according to  claim 13 , wherein the transgene of interest encodes a chimeric antigen receptor or a T-cell receptor, such that when the vector is used to transduce a target cell, the target cell co-expresses said polypeptide and said chimeric antigen receptor or T-cell receptor. 
     
     
         15 . A cell which expresses the polypeptide according to  claim 1 . 
     
     
         16 . The cell according to  claim 15  which co-expresses the polypeptide and a protein of interest (POI) at the cell surface. 
     
     
         17 . The cell according to  claim 15  which comprises a nucleic acid sequence that encodes the polypeptide according to  claim 1  or encodes a fusion protein that comprises said polypeptide fused to a protein of interest (POI) according to  claim 11 . 
     
     
         18 . The cell according to  claim 15 , which is a T cell. 
     
     
         19 - 29 . (canceled) 
     
     
         30 . The cell according to  claim 15  for use in adoptive cell transfer.