CD123-specific chimeric antigen receptor redirected T cells and methods of their use
A family of chimeric antigen receptors (CARs) containing a CD123 specific scFv was developed to target different epitopes on CD123. In some embodiments, such a CD123 chimeric antigen receptor (CD123CAR) gene includes an anti-CD123 scFv region fused in frame to a modified IgG4 hinge region comprising an S228P substitution, an L235E substitution, and optionally an N297Q substitution; a costimulatory signaling domain; and a T cell receptor (TCR) zeta chain signaling domain. When expressed in healthy donor T cells (CD4/CD8), the CD123CARs redirect T cell specificity and mediated potent effector activity against CD123+ cell lines as well as primary AML patient samples. Further, T cells obtained from patients with active AML can be modified to express CD123CAR genes and are able to lyse autologous AML blasts in vitro. Finally, a single dose of 5.0×10 6 CAR123 T cells results in significantly delayed leukemic progression in mice. These results suggest that CD123CAR-transduced T cells may be used as an immunotherapy for the treatment of high risk AML.
1. A population of human T cells harboring an expression vector comprising a nucleic acid molecule encoding a chimeric antigen receptor comprising: an anti-CD123 scFv region, an IgG4 hinge region comprising SEQ ID NO: 13 having an N to Q amino acid substitution at position 79 and a L to E amino acid substitution at position 17 and, optionally, an S to P amino acid substitution at position 10, and a T cell receptor zeta chain signaling domain.
2. The population of human T cells of claim 1 , wherein the IgG4 hinge region comprising SEQ ID NO:13 has a S to P amino acid substitution at position 10.
3. The population of human T cells of claim 1 , wherein the chimeric antigen receptor further comprises a co-stimulatory signaling domain selected from the group consisting of: a CD27 co-stimulatory signaling domain, a CD28 co-stimulatory signaling domain, a 4-1BB co-stimulatory signaling domain, and an OX40 co-stimulatory signaling domain.
4. The population of human T cells of claim 1 , wherein the anti-CD123 scFV domain comprises: the VL and VH domain of recombinant immunotoxin 26292 or the VL and VH domain of recombinant immunotoxin 32716.
5. The population of human T cells of claim 1 , wherein the chimeric antigen receptor comprises an amino acid sequence selected from the group consisting of: SEQ ID NO:11 and SEQ ID NO:12.
6. The population of human T cells of claim 1 , wherein the expression vector comprises a nucleotide sequence selected from the group consisting of: SEQ ID NO: 1, SEQ ID NO:2, SEQ ID NO:3 and SEQ ID NO:4.
7. The population of human T cells of claim 1 , wherein the chimeric antigen receptor comprises a CD28 transmembrane domain.
8. The population of human T cells of claim 1 , wherein the expression vector is a viral vector.
9. The population of human T cells of claim 1 , wherein the viral vector is a lentiviral vector.
10. The population of human T cells of claim 1 , wherein the wherein the anti-CD123 scFv region is a humanized anti-CD123 scFv region.
11. The population of human T cells of claim 1 , wherein the wherein the anti-CD123 scFv region comprises amino acids 23-266 of SEQ ID NO:9.
12. The population of human T cells of claim 1 , wherein the anti-CD123 scFv region comprises amino acids 23-259 of SEQ ID NO:10.
13. The population of human T cells of claim 1 , wherein the wherein the IgG4 hinge region comprises amino 267-495 of SEQ ID NO:9.
14. The population of human T cells of claim 1 , wherein the chimeric antigen receptor further comprises a 4-1BB co-stimulatory signaling domain.
15. The population of human T cells of claim 1 , wherein the wherein the chimeric antigen receptor further comprises a CD28 co-stimulatory signaling domain.
16. The population of human T cells of claim 1 , wherein the CD28 co-stimulatory domain comprises amino acids 498-564 of SEQ ID NO:9.
17. The population of human T cells of claim 1 , wherein the CD28 co-stimulatory domain comprises amino acids 489-557 of SEQ ID NO:10.
18. The population of human T cells of claim 1 , wherein the T cell receptor zeta chain signaling domain comprises amino acids 568-679 of SEQ ID NO:9.