EPHA2 T-CELL EPITOPE AGONISTS AND USES THEREFORE
EphA2 T-cell epitope are provided herein. The epitopes include peptides corresponding to specific fragments of human EphA2 protein containing one or more T-cell epitopes, and conservative derivatives thereof. The EphA2 T-cell epitopes are useful in an assay, such as an ELISPOT assay, that may be used to determine and/or quantify a patient's immune responsiveness to EphA2. The epitopes also are useful in methods of modulating a patient's immune reactivity to EphA2, which has substantial utility as a treatment for cancers that overexpress EphA2, such as renal cell carcinoma (RCC). The EphA2 epitopes also can be used to vaccinate a patient against EphA2, by in vivo or ex vivo methods.
1 . An isolated peptide that consists of 9-35 amino acid residues, wherein said isolated peptide comprises the peptide of VLAGVGFFI (SEQ ID NO: 2, residues 550-558), IMNDMPIYM (SEQ ID NO: 2, residues 58-66), WLVPIGQCL (SEQ ID NO: 2, residues 253-261); LLWGCALAA (SEQ ID NO: 2, residues 12-20); or NLYYAESDL (SEQ ID NO: 2, residues 120-128),
where said peptide of VLAGVGFFI (SEQ ID NO: 2, residues 550-558), IMNDMPIYM (SEQ ID NO: 2, residues 58-66), WLVPIGQCL (SEQ ID NO: 2, residues 253-261); LLWGCALAA (SEQ ID NO: 2, residues 12-20); or NLYYAESDL (SEQ ID NO: 2, residues 120-128):
(i) has up to one conservative amino acid substitution within the conservative substitution groups (a) S and T, (b) L, I and V, and (c) E and D; and
(ii) retains the ability to stimulate a T-cell immune response to EphA2 as determined by ELISPOT assay.
2 . The isolated peptide of claim 1 , comprising the peptide VLAGVGFFI (SEQ ID NO: 2, residues 550-558)).
3 . The isolated peptide of claim 1 , comprising the peptide IMNDMPIYM (SEQ ID NO: 2, residues 58-66).
4 . The isolated peptide of claim 1 , comprising the peptide WLVPIGQCL (SEQ ID NO: 2, residues 253-261).
5 . The isolated peptide of claim 1 , comprising the peptide LLWGCALAA (SEQ ID NO: 2, residues 12-20).
6 . The isolated peptide of claim 1 , comprising the peptide NLYYAESDL (SEQ ID NO: 2, residues 120-128).
7 . A vaccine formulation comprising an isolated peptide that consists of 9-35 amino acid residues, wherein said isolated peptide comprises the peptide of VLAGVGFFI (SEQ ID NO: 2, residues 550-558), EVINDMPIYM (SEQ ID NO: 2, residues 58-66), WLVPIGQCL (SEQ ID NO: 2, residues 253-261); LLWGCALAA (SEQ ID NO: 2, residues 12-20); or NLYYAESDL (SEQ ID NO: 2, residues 120-128),
where said peptide of VLAGVGFFI (SEQ ID NO: 2, residues 550-558), IMNDMPIYM (SEQ ID NO: 2, residues 58-66), WLVPIGQCL (SEQ ID NO: 2, residues 253-261); LLWGCALAA (SEQ ID NO: 2, residues 12-20); or NLYYAESDL (SEQ ID NO: 2, residues 120-128):
(i) has up to one conservative amino acid substitution within the conservative substitution groups (a) S and T, (b) L, I and V, and (c) E and D; and
(ii) retains the ability to stimulate a T-cell immune response to EphA2 as determined by ELISPOT assay, and a pharmaceutically acceptable carrier.
8 . The vaccine formulation of claim 7 , where the isolated peptide comprises the peptide VLAGVGFFI (SEQ ID NO: 2, residues 550-558).
9 . The vaccine formulation of claim 7 , where the isolated peptide comprises the peptide IMNDMPIYM (SEQ ID NO: 2, residues 58-66).
10 . The vaccine formulation of claim 7 , where the isolated peptide comprises the peptide WLVPIGQCL (SEQ ID NO: 2, residues 253-261).
11 . The vaccine formulation of claim 7 , where the isolated peptide comprises the peptide LLWGCALAA (SEQ ID NO: 2, residues 12-20).
12 . The vaccine formulation of claim 5 , where the isolated peptide comprises the peptide NLYYAESDL (SEQ ID NO: 2, residues 120-128).
13 . The vaccine formulation of claim 7 , further comprising an adjuvant.
14 . The vaccine formulation of claim 7 , wherein the isolated peptide comprises a second peptide where said second peptide is not an EphA2 peptide and is immunogenic.
15 . A method of eliciting an immune response to EphA2 in a subject, comprising administering, to the subject, an effective amount of an isolated peptide that consists of 9-35 amino acid residues and wherein said isolated peptide comprises the peptide of VLAGVGFFI (SEQ ID NO: 2, residues 550-558), IMNDMPIYM (SEQ ID NO: 2, residues 58-66), WLVPIGQCL (SEQ ID NO: 2, residues 253-261); LLWGCALAA (SEQ ID NO: 2, residues 12-20); or NLYYAESDL (SEQ ID NO: 2, residues 120-128),
where said peptide of VLAGVGFFI (SEQ ID NO: 2, residues 550-558), IMNDMPIYM (SEQ ID NO: 2, residues 58-66), WLVPIGQCL (SEQ ID NO: 2, residues 253-261); LLWGCALAA (SEQ ID NO: 2, residues 12-20); or NLYYAESDL (SEQ ID NO: 2, residues 120-128):
(i) has up to one conservative amino acid substitution within the conservative substitution groups (a) S and T, (b) L, I and V, and (c) E and D; and
(ii) retains the ability to stimulate a T-cell immune response to EphA2 as determined by ELISPOT assay.
16 . A method of treating cancer in a patient in need thereof, said method comprising administering to the patient a therapeutically effective amount of a purified EphA2 T-cell epitope, wherein said EphA2 T-cell epitope binds to an MHC Class II molecule, wherein said EphA2 T-cell epitope is a peptide that consists of 9 to 35 contiguous amino acid residues of native human EphA2 (SEQ ID NO:2), wherein said peptide comprises the peptide of VLAGVGFFI (SEQ ID NO: 2, residues 550-558), IMNDMPIYM (SEQ ID NO: 2, residues 58-66), WLVPIGQCL (SEQ ID NO: 2, residues 253-261); LLWGCALAA (SEQ ID NO: 2, residues 12-20); or NLYYAESDL (SEQ ID NO: 2, residues 120-128).
17 . A method of monitoring the number and/or status of EphA2-reactive T-cells in a patient, said method comprising contacting a population of cells comprising cells from the patient and antigen-presenting cells with the EphA2 T-cell epitope, and determining immune reactivity of said population to the EphA2 T-cell epitope, wherein said EphA2 T-cell epitope is a peptide that consists of 9 to 35 contiguous amino acid residues of native human EphA2 (SEQ ID NO:2), wherein said peptide comprises the peptide of VLAGVGFFI (SEQ ID NO: 2, residues 550-558), IMNDMPIYM (SEQ ID NO: 2, residues 58-66), WLVPIGQCL (SEQ ID NO: 2, residues 253-261); LLWGCALAA (SEQ ID NO: 2, residues 12-20); or NLYYAESDL (SEQ ID NO: 2, residues 120-128).