Anti-WT1/HLA bi-specific antibody
Disclosed herein is a bi-specific form of a T cell receptor mimic (TCRm) mAb with reactivity to human immune effector cell antigen and a WT1 peptide/HLA-A epitope. This antibody selectively bound to leukemias and solid tumor cells expressing WT1 and HLA-A as well as activated resting human T cells to release interferon-(IFN-γ) and to kill the target cancer cells in vitro. Importantly, the antibody mediated autologous T cell proliferation and directed potent cytotoxicity against fresh ovarian cancer cells. Therapeutic activity in vivo of the antibody was demonstrated in NOD SCID SCID Yc*(NSG) mice with three different human cancers expressing WT1/HLA-A2 including disseminated Ph+ acute lymphocytic leukemia (ALL), disseminated acute myeloid leukemia, and peritoneal mesothelioma. In both of the leukemia xenograft models, mice that received the antibody and T cells also showed longer survival and delayed limb paralysis. Also provided are methods for stimulating a primary T cell response comprising stimulating cytotoxic T cells against a first tumor antigen and a secondary T cell response comprising stimulating effector T cells and/or memory T cells against a first tumor antigen and/or against a second tumor antigen using the bi-specific antibodies described herein.
1. A recombinant antibody comprising:
(i) a first antigen-binding portion comprising:
(A) a heavy chain (HC) variable region comprising HC-CDR1, HC-CDR2 and HC-CDR3, and a light chain (LC) variable region comprising LC-CDR1, LC-CDR2 and LC-CDR3, wherein:
(1) the HC-CDR1, HC-CDR2 and HC-CDR3 comprises amino acid sequences set forth in SEQ ID NOs: 2, 3, and 4, respectively, and the LC-CDR1, LC-CDR2 and LC-CDR3 comprises amino acid sequences set forth in SEQ ID NOs: 8, 9, and 10, respectively;
(2) the HC-CDR1, HC-CDR2 and HC-CDR3 comprises amino acid sequences set forth in SEQ ID NOs: 20, 21, and 22, respectively, and the LC-CDR1, LC-CDR2 and LC-CDR3 comprises amino acid sequences set forth in SEQ ID NOs: 26, 27, and 28, respectively;
(3) the HC-CDR1, HC-CDR2 and HC-CDR3 comprises amino acid sequences set forth in SEQ ID NOs: 38, 39, and 40, respectively, and the LC-CDR1, LC-CDR2 and LC-CDR3 comprises amino acid sequences set forth in SEQ ID NOs: 44, 45, and 46, respectively;
(4) the HC-CDR1, HC-CDR2 and HC-CDR3 comprises amino acid sequences set forth in SEQ ID NOs: 56, 57, and 58, respectively, and the LC-CDR1, LC-CDR2 and LC-CDR3 comprises amino acid sequences set forth in SEQ ID NOs: 62, 63, and 64, respectively;
(5) the HC-CDR1, HC-CDR2 and HC-CDR3 comprises amino acid sequences set forth in SEQ ID NOs: 92, 93, and 94, respectively, and the LC-CDR1, LC-CDR2 and LC-CDR3 comprises amino acid sequences set forth in SEQ ID NOs: 80, 81, and 82, respectively; or
(5) the HC-CDR1, HC-CDR2 and HC-CDR3 comprises amino acid sequences set forth in SEQ ID NOs: 74, 75, and 76, respectively, and the LC-CDR1, LC-CDR2 and LC-CDR3 comprises amino acid sequences set forth in SEQ ID NOs: 98, 99, and 100, respectively;
(B) a V H and a V L comprising first and second amino acid sequences as set forth in SEQ ID NOs: 14 and 16, 32 and 34, 50 and 52, 68 and 70, 86 and 88, or 104 and 106; or
(C) an scFv comprising an amino acid sequence as set forth in SEQ ID NO: 18, 36, 54, 72, 90, or 108; and
(ii) a second antigen-binding portion comprising an amino acid sequence set forth in SEQ ID NO: 111, 112, or 113.
2. The recombinant antibody of claim 1 , wherein said first antigen-binding portion and/or said second antigen-binding portion is an antibody fragment selected from the group consisting of a Fab fragment; a monovalent fragment consisting of the VL, VH, CL and CH1 domains; a F(ab)2 fragment; a bivalent fragment comprising two Fab fragments linked by a disulfide bridge at the hinge region; a Fd fragment consisting of the VH and CH1 domains; a Fv fragment consisting of the VL and VH domains of a single arm of an antibody; a dAb fragment; an isolated CDR; and a scFv.
3. The recombinant antibody of claim 2 , wherein said first antigen-binding portion and/or said second antigen-binding portion is a scFv.
4. The recombinant antibody of claim 1 , wherein said first antigen-binding portion specifically binds to WT1/HLA and said second antigen-binding portion specifically binds to an immune effector cell surface antigen.
5. The recombinant antibody of claim 4 , wherein said immune effector cell is selected from the group consisting natural killer (NK) cells, macrophages, and T cells.
6. The recombinant antibody of claim 4 , wherein said immune effector cell is a CD3 + cell and the recombinant antibody specifically binds to CD3.
7. The recombinant antibody of claim 1 , comprising the amino acid sequence set forth in SEQ ID NO: 110.
8. A pharmaceutical composition comprising the recombinant antibody of claim 1 .