FVIII CHIMERIC ANTIGEN RECEPTOR TREGS FOR TOLERANCE INDUCTION IN HEMOPHILIA A
Provided are materials and methods for generating chimeric antigen receptors (CARs) specific for human factor VIII (huF.VIII), which huF.VIII CARs are expressed in regulatory T cells and used to treat inhibitor formation in hemophilia A patients. Further provided are novel huF.VIII proteins and nucleic acids encoding the novel huF.VIII CAR as well as methods to treat inhibitor formation using therapeutically effective amounts of Tregs expressing the novel huF.VIII CAR.
1 . A chimeric antigen receptor (CAR) specific for human clotting factor VIII (huF.VIII) comprising:
a single chain antibody variable region (scFv);
a CD28 signaling domain; and
a CD3 zeta signaling domain.
2 . The CAR according to claim 1 , wherein the scFv is derived from an antibody produced by a B cell of a subject that has developed huF.VIII inhibitors and wherein the scFv recognizes huF.VIII.
3 . The CAR according to claim 1 or 2 , wherein the scFv recognizes a portion of huF.VIII, which portion comprises a C1 domain and a C2 domain of huF.VIII, or fragments thereof.
4 . The CAR according to any of claims 1 - 3 , wherein the scFv recognizes amino acids 2125 to 2332 of huF.VIII.
5 . The CAR according to claim 1 , wherein the CD3 zeta signaling domain comprises six immune-receptor tyrosine-based activation motifs (ITAMs), each comprising a YXXL/I sequence, wherein X corresponds to a variable amino acids.
6 . The CAR according to claim 5 , wherein at least one of the six ITAMs comprises a substitution of the tyrosine with a non-tyrosine amino acid.
7 . The CAR according to claim 6 , wherein the non-tyrosine amino acids is selected from phenylalanine and tryptophan.
8 . The CAR according to claim 6 , wherein the first, second, fifth, and sixth ITAMs comprise a substitution of the tyrosine with a non-tyrosine amino acid.
9 . A nucleic acid molecule comprising a nucleic acid sequence encoding a CAR according to any of claims 1 - 8 .
10 . A method for making a Treg cell expressing a CAR, the method comprising:
providing a Treg cell; and
introducing a nucleic acid molecule according to claim 9 into the Treg cell.
11 . The method according to claim 10 , further comprising introducing the nucleic acid molecule into a viral vector and introducing the viral vector into the Treg cell.
12 . A regulatory T cell (Treg) expressing the CAR according to any of claims 1 - 8 .
13 . A regulatory T cell (Treg) expressing the CAR according to claim 5 .
14 . A composition comprising a regulatory T cell according to claim 12 .
15 . A composition comprising a regulatory T cell according to claim 13 .
16 . A method for inducing tolerance to huF.VIII protein therapy in a subject suffering from hemophilia A, the method comprising:
administering the composition according to claim 14 to the subject in an effective amount to induce tolerance to huF.VIII protein therapy.
17 . A method for inducing tolerance to huF.VIII protein therapy in a subject suffering from hemophilia A and having been treated with huF.VIII protein therapy, the method comprising:
administering the composition according to claim 15 to the subject in an effective amount to induce tolerance to huF.VIII protein therapy.
18 . The CAR of claim 1 , wherein the a CD3 zeta signaling domain comprises a polypeptide sequence encoded by SEQ ID NO: 1 or SEQ ID NO:2.
19 . The method of claim 11 , wherein the viral vector is a lentiviral vector.
20 . The method of claim 19 , wherein the viral vector is encoded by a nucleic acid sequence comprising SEQ ID NO:3.
21 . The method according to claim 16 or 17 , wherein the composition is co-administered with huF.VIII protein therapy.