Use of Native Peptides and Their Optimized Derivatives For Vaccination

Abstract

The present invention pertains to the field of vaccination, and more particularly to the fields of antitumor and antiviral vaccination. The invention relates to the use of a native peptide in a medicinal composition, for selecting and/or boosting part of a CTL immune response which has been initiated by an optimized immunogenic peptide derived from said native peptide. The invention also concerns vaccination kits which comprise several doses of optimized peptides and of their cognate native peptides.

Description

[0001] This application is a continuation of U.S. application Ser. No. 11/913,138, filed Nov. 18, 2007, which is a national stage application filed under 35 U.S.C. 371 of International Application No PCT/EP2006/005325, filed May 9, 2006, which claims priority from European patent Application No. 05290984.3, filed May 9, 2005, the contents of which are incorporated herein by reference.

FIELD OF THE INVENTION

[0002] The present invention pertains to the field of vaccination, and more particularly to the fields of antitumor and antiviral vaccination. The invention concerns the use of a native peptide in a medicinal composition, for selecting and/or boosting part of a CTL immune response which has been initiated by an optimized immunogenic peptide derived from said native peptide.

BACKGROUND OF THE INVENTION

[0003] Cancer immunotherapy is intended to stimulate cytotoxic T lymphocytes (CTL) recognizing peptides derived from tumor antigens and presented at the tumor cell surface by HLA class 1 molecules. CTL targeted peptides can be dominant or cryptic (Moudgil and Sercarz 1994). Dominant peptides have high HLA affinity and are frequently presented by tumor cells. In contrast, cryptic peptides have low HLA affinity and are rarely presented by tumor cells. All cancer vaccines so far tested have targeted dominant peptides, with relatively little success (Slingluff, Yamshchikov et al. 2001; Knutson, Schiffman et al. 2002; Schaed, Klimek et al. 2002; Parkhurst, Riley et al. 2004; Vonderheide, Domchek et al. 2004). Studies using mouse models showed that this lack of efficacy is due to tolerance to tumor antigens, and especially to their dominant peptides (Cibotti, Kanellopoulos et al. 1992; Theobald, Biggs et al. 1997; Colella, Bullock et al. 2000; Hernandez, Lee et al. 2000; Grossmann, Davila et al. 2001; Gross, Graff-Dubois et al. 2004).

[0004] To circumvent this tolerance, vaccination with cryptic peptides was recently proposed. It was observed that in humanized mice, tolerance of cryptic peptides was weak or absent, and that cryptic peptides efficiently induced antitumoral immunity in vivo, providing their immunogenicity had been optimized (Tourdot, Scardino et al. 2000; Scardino, Gross et al. 2002; Gross, Graff-Dubois et al. 2004). A peptide sequence modification that optimizes immunogenicity of almost all low-affinity HLA-A*0201-restricted peptides tested was previously described (Tourdot, Scardino et al. 2000).

[0005] TERT₅₇₂Y is an HLA-A*0201-associated optimized cryptic peptide derived from TERT, an antigen overexpressed by 85% of human tumors (Kim, Piatyszek et al. 1994). TERT₅₇₂ is present in both human and murine TERT, and TERT₅₇₂Y was able to induce antitumoral immunity in HLA-A*0201 transgenic mice; however no autoimmunity against normal TERT-expressing tissues was observed (Gross, Graff-Dubois et al. 2004). In vitro, TERT₅₇₂Y stimulated antitumor CTLs from both healthy donors and prostate cancer patients. CTLs killed TERT-expressing tumor cells but not TERT-expressing normal cells (Hernandez, Garcia-Pons et al. 2002; Scardino, Gross et al. 2002).

[0006] However, in a similar vaccination approach, it has been reported that vaccination of melanoma patients with optimized gp100₂₀₉M led to the amplification of T cells that were no longer able to recognize either the native gp100₂₀₉ peptide or gp100-expressing melanoma cells (Clay, Custer et al. 1999).

[0007] Hence, there is presently a need for a vaccination protocol which enables the initiation and maintenance of a T cell response targeting sub-dominant or cryptic epitopes, especially when this response is initiated by optimized peptides.

SUMMARY OF THE INVENTION

[0008] The study disclosed in Example 1 below was designed to evaluate: i) the capacity of TERT₅₇₂Y to stimulate an antitumor immune response in vivo in patients with advanced cancer; and ii) the risk of inducing autoimmunity against TERT-expressing normal cells and tissues such as hematopoietic precursors, gut, thymus and liver. Vaccination of advanced cancer patients with TERT₅₇₂Y stimulated specific CTLs that were fully functional and able to kill in vitro tumor cells overexpressing TERT. Moreover, vaccination was safe and did not induce any autoimmunity against TERT positive normal tissues. This is the first in vivo demonstration in humans that optimized cryptic peptides can be considered for tumor immunotherapy.

[0009] Moreover, these results, as well as those presented in Examples 2, 3 and 4, show that injection of a native peptide, following vaccination with its cognate optimized peptide, can maintain the immune response initiated by said optimized peptide. Without being bound by theory, it can be hypothesized that the use of the native peptide allows to select and/or boost, among T cells recruited by the optimized peptide, those with the highest specificity for the native peptide presented by tumor cells.

[0010] These findings allow to propose the use of a native cryptic or non-optimized peptide for improving the CTL immune response raised by a cognate optimized peptide.

[0011] A "cryptic peptide" for a given MHC molecule is a peptide which is capable to bind said MHC molecule, but only with a weak affinity for the MHC molecule and/or a weak stability of the MHC/peptide complex. As a result this peptide is only poorly presented by said MHC molecule at the surface of an antigen presenting cell, and thus participate only slightly, or not at all, in the CTL response to the antigen from which said peptide is derived. For example, in the case of HLA A2, cryptic peptides can be defined as peptides which have a low affinity and a weak stabilizing ability (RA>5 and DC₅₀<2 hours), as described in WO 0208716.

[0012] A "native peptide" (cryptic or not) is a peptide which corresponds to a fragment of an antigen, without any sequence modification.

[0013] An "optimized peptide" for a given native peptide is a peptide obtained by one or several amino acid substitutions in said native peptide, said modifications resulting in a greater affinity for the MHC molecule and/or a greater stability of the MHC/peptide complex. For example, HLA-A2.1-associated peptides can be optimized by modifying their sequence by introducing a tyrosine in the first position (P1Y substitution) (Tourdot, Scardino et al. 2000). A method for identifying cryptic peptides and generating cognate optimized peptides is disclosed for instance in PCT WO 02/08716, the content of which is incorporated herein by reference. Other modifications for optimizing HLA A2 peptides have also been described, such as substituting the amino acid in position 2 by a methionine or a leucine (Parkhurst, Salgaller et al. 1996; Bakker, van der Burg et al. 1997; Valmori, Fonteneau et al. 1998), or substituting the C-terminal amino acid by a valine or a leucine (Parkhurst, Salgaller et al. 1996). These peptide modifications can be done to obtain optimized peptides to perform the present invention.

[0014] A cryptic peptide is not able to generate in vitro a specific CTL response against target cells expressing the protein from which it is derived. In contrast, the cognate optimized peptide is able to generate a specific CTL response against the same target cells, wherein at least part of the CTLs have a high avidity for said cryptic peptide.

[0015] An object of the present invention is the use of a native peptide, for producing a medicinal composition for maintaining the CTL immune response initiated by its cognate optimized peptide. According a preferred embodiment of the invention, the native peptide is sub-dominant or cryptic.

[0016] The present invention is particularly useful in the domain of antitumor or antiviral immunotherapy. Accordingly, the native peptide is advantageously from a tumor antigen or from a viral antigen, especially from an antigen from a virus which produces long-lasting infections, such as HIV, HCV and HBV.

[0017] According to the invention, a native peptide can be used for vaccination of patients having previously received a cognate optimized peptide.

[0018] The present invention thus encompasses a method for vaccinating a patient against a tumoral or viral antigen, wherein said method comprises a first step of vaccination with an optimized peptide cognate to a native peptide of said antigen, particularly a cryptic peptide, followed by a second step of vaccination with said native peptide.

[0019] An example of antitumoral vaccination using the native cryptic peptide TERT₅₇₂ (RLFFYRKSV) and its cognate optimized peptide TERT₅₇₂Y (YLFFYRKSV), is given hereinafter in Example 1.

[0020] According to a preferred embodiment of the invention, the cryptic peptide is presented by HLA A2, and the optimized peptide results from the substitution of the N-terminal amino acid of said cryptic peptide with a tyrosine residue. Non-limitative examples of couples of cryptic peptides and optimized peptides, presented by HLA A2, and which can be used in the present invention are described in PCT WO 02/08716 and in Table 1 below. Other couples of native and cognate optimized peptides which can be used according to the present invention, are also presented in Table 1.

[0021] Another aspect of the present invention is a process for in vitro obtaining CTLs having high avidity for a native peptide, especially a native cryptic peptide, by stimulating, with said native peptide, the CTLs which are present in a biological sample from a patient who has been immunized with a cognate optimized peptide. In this process, the native and optimized peptides are advantageously as described above.

[0022] The present invention also pertains to a kit of parts for the vaccination, comprising at least one dose of a native peptide and at least one dose of its cognate optimized peptide. In a preferred embodiment, the vaccination kit comprises 2 or 3 doses of optimized peptide, and 3, 4, 5 or 6 doses of native peptide. A particular vaccination kit according to the invention is adapted for the first vaccination sequence of 6 injections, and comprises 2 or 3 doses of optimized peptide, and 4 or 3 doses of native peptide. In case of long-lasting diseases, it is preferable to maintain the level of immunity obtained after this primo-vaccination, by regular recalls. This can be done, for example, by injections performed every 3 to 6 months. Therefore, complementary kits, comprising at least 2 doses, and up to 40 or 50 doses of native peptide, are also part of the present invention. Alternatively, the vaccination kit can comprise 2 to 3 doses of optimized peptide, and 3 to 40 or up to 50 doses of native peptide. Of course, said native and optimized peptides present in the kit are as described above.

[0023] Each dose comprises between 0.5 and 10 mg of peptide, preferably from 1 to 5 mg. In a preferred embodiment, each dose is formulated for subcutaneous injection. For example, each dose can be formulated in 0.3 to 1.5 ml of an emulsion of aqueous solution emulsified with Montanide, used as an adjuvant. The skilled artisan can choose any other adjuvant(s) in place of (or in addition to) Montanide. In a particular embodiment, the doses are in the form of an aqueous solution. Alternatively, the doses can be in the form of a lyophilized peptide, for extemporaneous preparation of the liquid solution to be injected.

TABLE-US-00001 TABLE 1 examples of couples of native and optimized peptides, presented by HLA A2, which can be used according to the invention. Native peptide Optimized peptide Reference Name Sequence No Name Sequence No HIVgag₇₆ SLYNTVATL 13 HIVgag₇₆Y1 YLYNTVATL 14 WO 0208716 FluM₅₈ GIGLFVFTL 11 FluM₅₈Y1 YIGLFVFTL 12 HBVpol₅₇₅ FLLSLGIHL 15 HBVpol₅₇₅y1 YLLSLGIHL 16 HBVpol₇₆₅ LLGCAANWIL 17 HBVpol₇₆₅Y1 YLGCAANWIL 18 Mart-1₂₇ AAGIGILTV 19 Mart-1₂₇Y1 YAGIGILTV 20 Mart-1₂₆ EAAGIGILTV 21 Mart-1₂₆L27 ELAGIGILTV 22 Valmori, D., 1998 Gp 100₁₇₇ AMLGTHTMEV 23 Gp 100₁₇₇Y1 YMLGTHTMEV 24 WO 0208716 Gp 100₁₇₈ MLGTHTMEV 25 Gp 100₁₇₈Y1 YLGTHTMEV 26 Gp 100₁₅₄ KTWGQYWQV 8 Gp 100₁₅₄Y1 YTWGQYWQV 9 Gp 100₁₅₄M155 KMWGQYWQV 10 Bakker, A.B., 1997 Gp 100₅₇₀ SLADTNSLAV 27 Gp 100₅₇₀Y1 YLADTNSLAV 28 WO 0208716 Gp 100₂₀₉ TDQVPFSV 29 Gp 100₂₀₉Y1 YDQVPFSV 30 Gp 100₂₀₉M210 YMQVPFSV 31 Parkhust, M.R., 1996 Gp 100₄₇₆ VLYRYGSFSV 32 Gp 100₄₇₆Y1 YLYRYGSFSV 33 WO 0208716 Gp 100₄₅₇ LLDGTATLRL 34 Gp 100₄₅₇Y1 YLDGTATLRL 35 HER-2/neu₇₉₉ QLMPYGCLL 36 HER-2/neu₇₉₉Y1 YLMPYGCLL 37 HER-2/neu₃₆₉ KIFGSLAFL 38 HER-2/neu₃₆₉Y1 YIFGSLAFL 39 HER-2/neu₇₈₉ CLTSTVQLV 40 HER-2/neu₇₈₉Y1 YLTSTVQLV 41 HER-2/neu₄₈ HLYQGCQW 42 HER-2/neu₄₈Y1 YLYQGCQW 43 HER-2/neu₇₇₃ VMAGVGSPYV 44 HER-2/neu₇₇₃Y1 YMAGVGSPYV 45 HER-2/neu₅ ALCRWGLL 46 HER-2/neu₅Y1 YLCRWGLL 47 HER-2/neu₈₅₁ VLVKSPNHV 48 HER-2/neu₈₅₁Y1 YLVKSPNHV 49 HER-2/neu₆₆₁ ILLVVVLGV 50 HER-2/neu₆₆₁Y1 YLLVVVLGV 51 HER-2/neu₆₅₀ PLTSIISAV 52 HER-2/neu₆₅₀Y1 YLTSIISAV 53 HER-2/neu₄₆₆ ALIHHNTHL 54 HER-2/neu₄₆₆Y1 YLIHHNTHL 55 HER-2/neu₄₀₂ TLEEITGYL 56 HER-2/neu₄₀₂Y1 YLEEITGYL 57 HER-2/neu₃₉₁ PLQPEQLQV 58 HER-2/neu₃₉₁Y1 YLQPEQLQV 59 HER-2/neu₉₇₁ ELVSEFSRM 60 HER-2/neu₉₇₁Y1 YLVSEFSRM 61 HBVpol₂₈ LLDDEAGPL 62 HBVpo1₂₈Y1 YLDDEAGPL 63 HBVpol₅₉₄ PLEEELPRL 64 HBVpol₅₉₄Y1 YLEEELPRL 65 HBVpol₉₈₅ NLQSLTNLL 66 HBVpol₉₈₅Y1 YLQSLTNLL 67 EphA2₆₁ DMPIYMYSV 68 EphA2₆₁Y1 YMPIYMYSV 69 WO 03091383 HER2₉₁₁ TVWELMTFGA 70 HER₉₁₁Y1V10 YVWELMTFGV 71 HER4₉₁₁ TIWELMTFGG 72 HER1₉₁₁ TVWELMTFGS 73 HER2₇₂₂ KVKVLGSGA 74 HER₇₂₂Y1V9 YVKVLGSGV 75 HER3₇₂₂ KLKVLGSGV 76 HER4₇₂₂ RVKVLGSGA 77 HER1₇₂₂ KIKVLGSGA 78 HER2₈₄₅ DLAARNVLV 79 HER₈₄₅Y1 YLAARNVLV 80 HER3₈₄₅ NLAARNVLL 81 HER2₉₀₄ DVWSYGVTV 82 HER₉₀₄Y1 YVWSYGVTV 83 WO 03083124 HER4₉₀₄ DVWSYGVTI 84 HER2₉₃₃ DLLEKGERL 85 HER₉₃₃Y1 YLLEKGERL 86 HER1₉₃₃ SILELKGERL 87 HER2₉₄₅ PICTIDVYMI 88 HER₉₄₅Y1 YICTIDVYMV 90 HER3₉₄₅ QICTIDVYMV 89 HER4₉₄₅ PICTIDVYMV 91 HER1₉₄₅ PICTIDVYKI 92 MAGE-A₂₄₈G9 YLEYRQVPG 7 MAGE-A₂₄₈V9 YLEYRQVPV 6 MAGE-A₂₄₈D9 YLEYRQVPD 5 TERT₉₈₈ DLQVNSLQTV 3 TERT₉₈₈Y1 YLQVNSLQTV 4 WO 0208716 TERT₅₇₂ RLFFYRKSV 1 TERT₅₇₂Y1 YLFFYRKSV 2

[0024] The invention is further illustrated by the following figures and examples.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] FIG. 1: TERT₅₇₂Y-specific CD8 cells detected ex vivo in patients #1, #3, #8, #11 and #13. Thawed PBMC from patients #1, #8, #11 and #13 collected before vaccination and after the second (#1, #8, #11) and sixth (#13) vaccine injections were stained with PE-labeled TERT₅₇₂Y tetramer, APC-labeled anti-CD8 and FITC-labeled anti-CD3. CD3+ gated cells were analyzed.

[0026] FIG. 2: TERT₅₇₂Y-specific CD8 cells detected after in vitro stimulation of PBMC from patients #6 and #18. Thawed PBMC from patients #6 and #18 were cultured in the absence (unstimulated) or presence (stimulated) of 10 μM TERT₅₇₂Y for nine days. Cells were then stained and analyzed as described in the legend of FIG. 1.

[0027] FIG. 3: Time course of immune responses.

[0028] FIG. 4: Functional analysis of TERT₅₇₂Y-specific CD8 cells induced by vaccination:

[0029] A) PBMC from patient #4, collected three weeks after the second vaccine injection, were stimulated in vitro with TERT₅₇₂Y peptide for nine days. TERT₅₇₂Y specific cells were purified and amplified with PHA. Amplified cells were stained with TERT₅₇₂Y tetramer and CD8 mAb.

[0030] B) TERT₅₇₂Y tetramer-positive cells were stimulated with TERT₅₇₂Y and irrelevant FluM58 peptides for 6 hours, then stained with PE-labeled anti-CD107a, permeabilized with Saponin and stained with FITC-labeled anti-IFNγ to evaluate intracellular IFNγ.

[0031] C) TERT₅₇₂Y tetramer-positive cells were incubated with ⁵¹Cr-labeled N418 and TERT-transfected N418 cells for four hours in a classical ⁵¹Cr release assay. E/T ratios are indicated.

[0032] D) TERT₅₇₂Y tetramer-positive cells were incubated with ⁵¹Cr-labeled NA8 and ME290 tumor cells for four hours in a classical ⁵¹Cr release assay. E/T ratios are indicated.

EXAMPLES

Example 1

Safety and Immunogenicity of the Optimized Cryptic Peptide TERT₅₇₂Y in Patients with Advanced Malignancies: Phase I Clinical Study

1.1. Patients and Methods

Patients

[0033] Patients with chemotherapy-resistant malignant tumors were eligible for the study. Other eligibility criteria were: progressive disease for which there was no other therapeutic option of proven benefit; an expected survival of at least 6 months; patients had to be HLA-A*0201 positive; age 18-75 years old, performance status (WHO)<2, adequate bone marrow (absolute neutrophil count≧1500/mm³; absolute lymphocyte count≧1300/mm³; platelets>100000/mm³; Hgb>10 g/dl), renal (creatinine<1.5 mg/dl) and liver (bilirubin<1.5 times the upper normal value) function. Patients were excluded if they had received chemotherapy, radiotherapy, hormonotherapy, immunotherapy or corticosteroids within one month before enrolment or if they had a known immunodeficiency or auto-immune disease. The protocol had been approved by the Ethics and Scientific Committees of the University Hospital of Heraklion and the National Drug Administration of Greece. All patients gave written informed consent in order to participate in the study.

Peptide Vaccine Preparation

[0034] The vaccine consisted of optimized TERT₅₇₂Y (YLFFYRKSV) and native TERT₅₇₂ (RLFFYRKSV) peptides emulsified in Montanide ISA51 (Seppic Inc, France). The vaccine peptides were synthesized at the Faculty of Pharmacy, University of Patras (Greece) by means of solid-phase Fmoc/Bu chemistry. Quality assurance studies included confirmation of identity, sterility and purity (>95% for both peptides). No decrease in purity or concentration was observed after more than two years of storage at -80° C. Each peptide was prepared as a lyophilized powder for reconstitution and dilution in sterile water.

Vaccination Protocol

[0035] Patients received a total of six subcutaneous vaccinations administered every 3 weeks. Peptides in 0.5 ml aqueous solution were emulsified with 0.5 ml Montanide ISA51 immediately before being injected. The optimized TERT₅₇₂Y peptide was used for the first 2 vaccinations and the native TERT₅₇₂ peptide for the remaining 4 vaccinations. Five dose levels of the peptides were studied; dose levels included 2, 3, 4, 5 and 6 mg of both peptides. Three patients were entered at each dose level. An additional 3 patients were planned to be enrolled at the dose level where a dose-limiting event was observed. Each patient received the same peptide dose for all six vaccinations. No other treatment with possible antitumor activity, i.e., chemotherapy, radiotherapy, hormonal therapy or administration of corticosteroids, was allowed during the course of vaccination.

Patient Evaluation

[0036] Before entering the study, all patients were assessed by complete medical history, physical examination, and complete blood cell count with differential, serum chemistry and baseline measurements of relevant tumor markers. Moreover, measurable disease was determined by standard imaging procedures (chest x-ray, ultrasound, computed tomography scans of thorax and abdomen, magnetic resonance imaging (MRI) if indicated, and whole body bone scans). Toxicity during the vaccination protocol was evaluated by repeating the complete blood cell count weekly and by performing medical history, physical examination and serum chemistry every three weeks before each subsequent injection during the vaccination period and every month thereafter during the follow up. Toxicity was assessed and scored using the National Cancer Institute (NCI) Common Toxicity Criteria (Ajani, Welch et al. 1990). Dose-limiting toxicity (DLT) was assessed during the entire vaccination protocol and was defined as the occurrence of any of the following: grade 4 hematologic toxicity; grade 3-4 neutropenia with fever>38.2° C.; grade 3-4 non-hematologic toxicity; and any treatment delay because of toxicity. Dose escalation was discontinued and the DLT dose level was reached if at least 50% of the patients treated at that level develop a DLT. The MTD dose level was defined as the first level below the DLT dose level.

[0037] Response to treatment was evaluated by repeating the baseline imaging studies and relevant tumor marker measurements after every 2 vaccinations or sooner if clinically indicated. Response to treatment was scored as complete response (CR), partial response (PR), stable disease (SD) and progressive disease (PD) using the standard WHO criteria (Miller, Hoogstraten et al. 1981). Radiological responses were confirmed by an independent panel of radiologists. CR and PR had to be maintained for a minimum of 4 weeks. The duration of response was measured from the first documentation of response to disease progression. Time to progression (TTP) was determined by the interval between the initiation of therapy to the first date that disease progression was objectively documented. Overall survival (OS) was measured from the date of study entry to the date of death. The follow up time was measured from the day of first treatment administration to last contact or death. Immune responses were examined before the first injection, and after the second, fourth and sixth injections. Peripheral blood mononuclear cells (PBMC) were collected at each time point and frozen.

Cell Lines

[0038] T2 is a mutant human TB hybrid that lacks TAP molecules but expresses HLA-A*0201. HLA-A*0201-positive N418 fibroblasts, TERT-transfected N418 cells and the melanoma cell lines Nab and Me290 were provided by P. Romero (Ludwig Institute for Cancer Research, Lausanne, Switzerland).

Peptides

[0039] Class I-restricted peptides used for laboratory studies included TERT₅₇₂ (RLFFYRKSV, SEQ ID No: 1), TERT₅₇₂Y (YLFFYRKSV, SEQ ID No: 2), and FluM₅₈ (GILGFVFTL, SEQ ID No: 11), all produced by Epytop (Nimes, France).

In Vitro Stimulation of PBMC

[0040] Thawed PBMC (3×10⁵ cells/well in 200 μl) were incubated in the presence of 10 μM TERT₅₇₂Y peptide in complete medium (RPMI 1640 supplemented with 8% human AB serum) in 96-well round-bottom plates. IL2 was added at a final concentration of 10 U/ml after 48 h and 96 h. Cells were incubated at 37° C. in 5% CO₂-air. On day 9 of culture, cells from six wells were pooled and analyzed for the presence of TERT₅₇₂Y-specific CD8 cells by TERT₅₇₂Y tetramer staining.

TERT₅₇₂Y Tetramer Staining

[0041] Cells were incubated with PE-conjugated TERT₅₇₂Y tetramer (Proimmune Ltd, Oxford, UK) for 30 min at room temperature, and then with APC-conjugated anti-CD8 (BD Pharmingen, Mississauga, Canada) and FITC-conjugated anti-CD3 (BD Pharmingen, Mississauga, Canada) mAbs for 30 min at 4° C. Stained cells were analyzed by flow cytometry (FACSCalibur, BD Biosciences, Mountain View, Calif.).

Polyclonal Expansion of TERT₅₇₂Y Tetramer-Positive Cells

[0042] PBMCs were stimulated with 10 μM TERT₅₇₂Y in the presence of 10 U/ml IL2 for 9 days. Cells were labeled with anti-CD8 mAb and TERT₅₇₂Y tetramer before isolation with a cell sorter. Sorted cells were stimulated with PHA (Difco) for 14 days.

CD107 and Intracellular IFNγ Double Labeling

[0043] T cells were stimulated with T2 cells loaded with peptide (10 μM) in the presence of 20 μg/ml Brefeldin A (Sigma, Oakville, Canada). Six hours later they were washed, stained with PE-conjugated anti-CD107 mAb (BD Pharmingen, Mississauga, Canada) in PBS for 25 minutes at 4° C., washed again and fixed with 4% paraformaldehyde. The cells were permeabilized with PBS/0.2% Saponin/0.5% BSA (Sigma) and stained with APC-conjugated anti-IFNγ mAb (BD Pharmingen, Mississauga, Canada) before flow cytometric analysis (FACSCalibur, BD Biosciences, Mountain View, Calif.).

Cytotoxicity Assay

[0044] Target cells were labeled with 100 μCi of ⁵¹Cr for 90 min, washed twice, and plated in 96-well round-bottom plates (3×10³ cells/well in 100 μl of RPMI 1640 plus 5% fetal calf serum). Effectors cells (100 μl) were then added to each well. After 4 h, 100 μl of supernatant was collected and radioactivity was measured with a gamma counter. The percentage of specific lysis was determined as follows: lysis=(experimental release-spontaneous release)/(maximum release-spontaneous release)×100.

1.2. Results

Patient Characteristics, Vaccination, and Clinical Responses

[0045] The characteristics of the 19 patients enrolled in the trial are shown in Table 2.

TABLE-US-00002 TABLE 2 Patient characteristics. NSCLC = non small cell lung cancer, S = surgery, CT = chemotherapy, HT = hormone therapy, RT = radiotherapy, IT = immunotherapy (IL2, INFα, PS = performance status, PD = progressive disease, SD = stable disease Dose Previous of No of Clinical Survival Pt Age Sex Cancer Stage PS treatment vaccine injections response (months) #1 73 M colorectal IV 1 7 lines 2 mg 4 PD 6.1 CT #2 75 F breast IV 1 5 lines 2 mg 6 PD 27.6 CT #3 64 M melanoma IV 1 1 line CT 2 mg 6 PD 8.8+ #4 60 M NSCLC IV 1 2 lines 3 mg 6 PD 22.8+ CT #5 71 M NSCLC IV 1 6 lines 3 mg 4 PD 5.7 CT #6 73 F cervix IV 1 2 lines 3 mg 6 PD 5.3 CT #7 53 M head and IV 1 4 lines 4 mg 6 PD 15.1 neck CT #8 57 F colorectal IV 1 5 lines 4 mg 6 PD 12.3 CT #9 66 M renal IV 1 1 line IT 4 mg 6 SD 11.1+ #10 73 F colorectal IV 1 2 lines 5 mg 6 PD 4.6 CT #11 49 M NSCLC IIIb 0 3 lines 5 mg 6 SD 17.5+ CT #12 45 F breast IV 1 2 lines 5 mg 6 SD 11.2+ CT #13 51 M renal IV 1 1 line CT, 6 mg 6 SD 6.9+ 1 line IT #14 61 M unknown IV 1 2 lines 6 mg 4 PD 8 origin CT #15 70 F colorectal IV 0 2 lines 6 mg 6 PD 10.7+ CT #16 69 M prostate IV 1 2 lines 6 mg 6 PD 17+ CT 1 line HT #17 69 F ovarian IV 1 8 lines 6 mg 6 PD 13.7+ CT #18 51 F ovarian IV 1 4 lines 6 mg 5 PD 6.4 CT #19 48 M esophagus IV 1 1 line CT 6 mg 4 PD 4.4+

[0046] All but one patient (patient #11) had stage IV cancer with multiple metastases mainly in the bones, liver and lung. They all had active and progressive disease and had received several treatments, mainly chemotherapy, before entering the vaccination protocol. Three patients were enrolled at dose levels 2, 3, 4 and 5 mg of the peptides, while seven patients received the 6 mg dose. Five patients were withdrawn from the protocol after the fourth (#1, #5, #14 and #19) or fifth (#18) vaccine injection because of rapid disease progression. All five patients subsequently died within six months of disease progression. The remaining 14 patients completed the vaccination protocol. The disease stabilized in four (29%) patients (#9, #11, #12 and #13) and continued to progress in 10 patients. The latter 10 patients subsequently received chemotherapy, and six of them are still alive. One (patient #11) of the 4 patients whose disease stabilized for 9 months subsequently progressed, while the other three patients still have stable disease (after 12 months for patients #9 and #12, and 9 months for patient #13) with no additional therapy after the end of vaccination.

[0047] Overall, after a median follow up of 10.7 months (range 4.4-27.6), nine patients have died, all due to disease progression. The median time to tumor progression was 4.2 months (range 2.3-11.2) and the median overall survival 15.2 months (range 4.4-27.6).

Toxicity and Adverse Events

[0048] No DLT was observed throughout the entire study and therefore the MTD dose level has not been reached (Table 3). Thirteen patients developed grade I toxicity. It consisted of local skin reaction (11 patients), anemia (6 patients), thrombocytopenia (2 patients), fatigue (1 patient) and anorexia (1 patient). Except of local skin reaction, other toxicities were most likely related to the disease rather than the vaccination. Grade I toxicities appeared early in the vaccination course. Three patients developed grade II toxicity consisting of fatigue (3 patients), nausea (2 patients) and anorexia (2 patients). In patient #5 (NSCLC) fatigue and nausea appeared after the third vaccination and disappeared two weeks later without any specific treatment. In patient #10 (colorectal cancer) fatigue, nausea and anorexia observed after the third vaccination were felt to be due to the disease rather than the vaccination. This patient developed a fatal intestinal obstruction. Patient #18 had an extremely rapid progression of her disease and consequently was taken off the protocol after the fourth vaccination. She died two months later. Specifically, no significant hematologic, renal, gastrointestinal or hepatic toxicity was observed although TERT is expressed in these normal cells and tissues. Patients were monitored for toxicity for a median of 10.7 months (range 4.4-27.6). Even after completing or discontinuing the vaccination program patients were followed monthly for the occurrence of any delayed toxicity. However, no signs or findings of delayed toxicity were observed.

TABLE-US-00003 TABLE 3 Toxicity Toxicity Patient Grade I Grade II Grade III/IV #1 no no no #2 Local skin no no #3 Anemia, local skin no no #4 Local skin no no #5 no fatigue, nausea no #6 Anemia, local skin, fatigue, no no anorexia #7 no no no #8 Thrombo/penia, local skin no no #9 Local skin no no #10 no anorexia, fatigue, no nausea #11 thrombocytopenia no no #12 Anemia, local skin no no #13 Local skin no no #14 Local skin no no #15 no no no #16 Anemia no no #17 Anemia, local skin no no #18 Local skin, anemia anorexia, fatigue no #19 no no no

Immune Responses

[0049] Peptide-specific CD8.sup.+ cells were detected in peripheral blood by triple staining of PBMCs with TERT₅₇₂Y tetramer, anti-CD8 and anti-CD3 mAbs, both ex vivo and after 9 days of stimulation in vitro with TERT₅₇₂Y peptide. In a preliminary study, TERT₅₇₂Y tetramer labeled less than 0.11% of CD8 cells in seven HLA-A*0201 healthy donors (mean 0.035±0.035, range 0.0-0.11%) (data not shown). The positivity cutoff for specific immunity was therefore set at 0.14% (mean+3SD) Immune responses were studied in 14 vaccinated patients (Table 4). Only one patient (#2) failed to respond to the vaccine. TERT₅₇₂Y-specific cells were detected ex vivo in four (29%) patients (FIG. 1). Specific immunity appeared after the second injection in patients #1, #8 and #11, and after the sixth vaccination in patient #13. It is noteworthy that, prior to vaccination, TERT₅₇₂Y tetramer labeled 0.29%, 0.33% and 1.00% of CD8.sup.+ cells in patients #1, #8 and #11 after in vitro PBMC stimulation (Table 4). TERT₅₇₂Y-specific cells were also detected in 9 patients (64%) after in vitro stimulation, 3 weeks after the 2^nd (#3, #4, #5, #6, #12, #15, and #19) or the 4^th (#7 and #18) injection. Representative results (patients #6 and #18) are shown in FIG. 2. Immune response was also measured 3 and 14 months after the end of the vaccination protocol in patients #13 and #11 respectively. In all two patients more than 1.5% of tetramer positive CD8 cells were detected after in vitro stimulation of their PBMC (FIG. 3).

TABLE-US-00004 TABLE 4 Percentage of tetramer TERT₅₇₂Y-positive CD8 cells among peripheral blood mononuclear cells of vaccinated patients. % above background in bold After the 2^nd or 4^th Pre-vaccination injection Post-vaccination Patient unstimulated stimulated unstimulated stimulated unstimulated stimulated #1 0.14 0.29 0.69 1.25 NT NT #2 0.02 0 0 0.11 NT NT #3 0 0 0.11 1.14 NT NT #4 NT NT 0.05 4.00 0.02 0.48 #5 0.01 0 0.06 0.36 NT NT #6 0 0.01 0 4.20 NT NT #7 0.02 0.14 0.01 0.42 0.12 0.36 #8 0.02 0.33 0.33 0.98 NT NT #11 0.3 1.00 0.7 1.30 0.05 0.52 #12 0.04 0.11 0.10 0.98 NT NT #13 0 0 0 0.88 0.32 0.48 #15 0 0.04 0.05 0.45 NT NT #18 0 0 0.06 0.62 NT NT #19 0 0.03 0 0.73 NT NT

[0050] To assess the functionality of TERT₅₇₂Y-specific CD8.sup.+ cells, TERT₅₇₂Y tetramer-positive cells from in vitro-stimulated PBMCs from patient #4 (FIG. 4A) were sorted, amplified with PHA and tested for their capacity to specifically respond to TERT₅₇₂Y peptide and to kill TERT-overexpressing tumor cells. More than 90% of amplified cells were labeled with TERT₅₇₂Y tetramer (FIG. 4A). Purified TERT₅₇₂Y-specific cells were fully functional, as they produced IFNγ and showed CD107a upregulation upon activation with TERT₅₇₂Y peptide (FIG. 4B). CTL recognized endogenous TERT and specifically killed TERT-transfected but not untransfected N418 fibroblasts (FIG. 4C). Importantly, CTLs killed tumor cells overexpressing TERT (Na8 cells) but not tumor cells expressing TERT at a low level (ME290 cells) (FIG. 4D).

1.3. Discussion

[0051] The aims of the present clinical trial were to evaluate the toxicity profile and to prove the concept that cryptic peptides derived from universal tumor antigens can induce immunity in cancer patients and can, therefore, be considered for tumor immunotherapy. The inventors used the cryptic peptide TERT₅₇₂, that is presented by HLA-A*0201 and is derived from TERT, a universal tumor antigen overexpressed by 85% of tumors. Immunogenicity had been enhanced by substituting the first amino acid by a tyrosine (Tourdot, Scardino et al. 2000). The results showed that TERT₅₇₂Y vaccination of patients with advanced cancer stimulates specific CTLs that are fully functional and are able to kill TERT-overexpressing tumor cells in vitro. Vaccination was well tolerated and did not appear to induce autoimmunity against TERT-expressing normal tissues. These results offer the first human in vivo confirmation that optimized cryptic peptides are good candidates for tumor immunotherapy.

[0052] Tumor antigens are non mutated self proteins also expressed by normal tissues, including the thymus, and are involved in tolerance induction. Tolerance, the process by which CTL, mainly those with high-avidity, are purged from the T cell repertoire, is a major barrier hindering the development of effective antitumor T cell responses. However, tolerance mainly shapes the T cell repertoire specific for dominant rather than cryptic peptides (Cibotti, Kanellopoulos et al. 1992; Moudgil and Sercarz 1994). Using a humanized mouse model, it was recently showed that vaccination with two cryptic peptides derived from murine TERT (TERT₅₇₂Y and TERT₉₈₈Y) recruited high-avidity CTLs capable of eliciting potent antitumoral immunity (Gross, Graff-Dubois et al. 2004). In the present clinical study, more than 90% of vaccinated patients developed specific T cells capable of killing TERT-overexpressing tumor cells. In contrast, only 50% of patients treated with the dominant peptide TERT₅₄₀ emulsified in Monatanide responded to the vaccine (Parkhurst, Riley et al. 2004). However, the natural processing of the dominant TERT540 described initially (Vonderheide, Hahn et al. 1999; Minev, Hipp et al. 2000; Vonderheide, Domchek et al. 2004) was not confirmed in more recent studies (Ayyoub, Migliaccio et al. 2001; Parkhurst, Riley et al. 2004), which suggests that possibly TERT540 does not belong to the immunological self. Given this ambiguity regarding the presentation of the dominant TERT540 peptide, a direct randomized comparison with the cryptic peptide could produce results which would be very difficult to interpret.

[0053] The vaccine response rate in the patients in the present study is higher than that obtained in the roughly fifty clinical studies of tumor vaccination reported to date (Pullarkat, Lee et al. 2003; Slingluff, Petroni et al. 2003). It is also noteworthy, that almost all previous clinical studies showing high immune response rates involved patients with minimal disease and excellent performance status (Disis, Gooley et al. 2002; Pullarkat, Lee et al. 2003; Disis, Schiffman et al. 2004; Vonderheide, Domchek et al. 2004). Scheibenbogen et al (Scheibenbogen, Lee et al. 1997) demonstrated that immune reactivity in melanoma patients correlated with disease remission. In contrast, in the present study, all patients had end-stage disease.

[0054] No correlation was found between the magnitude of the immune response and the dose of peptide administered. This is in agreement with recent data indicating that immune responses to HER2/neu vaccines did not depend on the vaccine dose (Disis, Schiffman et al. 2004). No correlation was found either between the vaccine dose and the time interval required for a detectable response to emerge. All 13 responding patients had detectable specific CTLs between the 2^nd and the 4^th vaccine injection. Rapid induction of immunity may be important in this setting, especially for patients with rapidly progressive malignancies.

[0055] The rationale for using native TERT₅₇₂ peptide for the 3^rd to the 6^th vaccine injections was to select, among T cells recruited by the optimized TERT₅₇₂Y, those with the highest specificity for TERT₅₇₂ presented by tumor cells. Indeed, Clay et al (Clay, Custer et al. 1999) have shown that vaccination of melanoma patients with optimized gp100₂₀₉M, amplified T cells that were no longer able to recognize either the native gp100₂₀₉ peptide or gp100-expressing melanoma cells. The above results show that injection of the native peptide can maintain the immune response initiated by the optimized peptide. Moreover, the persistence of the immune response more than one year after the end of vaccination suggests that native peptide presented on the surface of tumor cells can maintain the specific immune response by itself. The hallmark of antitumoral immunity in vivo is autoimmunity. Autoimmunity is acceptable when it targets non essential normal cells and tissues such as melanocytes, but may hamper vaccine development when it targets essential cells such as hematopoietic precursors. Although TERT is expressed by hematopoietic stem cells, gut, thymus, and activated B and T cells (Ramakrishnan, Eppenberger et al. 1998; Liu, Schoonmaker et al. 1999), none of the patients showed signs of autoimmunity even 24 months after the end of vaccination. This confirms previous results obtained in HLA-A*0201 transgenic HHD mice vaccinated with TERT₅₇₂Y peptide, which is also part of murine TERT (Gross, Graff-Dubois et al. 2004). Vaccinated HHD mice developed antitumor immunity without signs of autoimmunity. Moreover, TERT₅₇₂Y-specific CTLs killed tumor cells but not activated B cells. A possible explanation is that TERT expression is insufficient on normal cells (contrary to tumor cells) to permit the presentation of low-affinity peptides like TERT₅₇₂.

[0056] The observed toxicity in the present study was essentially minimal and with the exception of transient skin reactions caused by the Montanide adjuvant, all the other mild toxicities could also be attributed to the underlying disease. Given the limitations of the small number of patients enrolled in this trial and the relatively short follow up due to the advanced disease, it can be concluded that this vaccination program is free of any major acute and short-term toxicity. However, long-term toxicities will have to be evaluated in patients with better prognosis who are more likely to be cured of their malignant disease.

[0057] For ethical reasons, this study involved patients with end-stage cancer, who are not the best candidates for tumor immunotherapy. It is now generally agreed that immunotherapy is best administered to patients with minimal residual disease, and the goal should be to prevent relapse rather than to cure advanced cancer. The inability of vaccines to eradicate actively growing tumors has been clearly shown in animals models (Cheever and Chen 1997). Although clinical antitumor activity by means of tumor shrinkage was not observed in this heavily pretreated group of patients, four patients showed long lasting disease stabilization in this phase I trial. These patients had previously progressive disease and developed TERT-specific CTL which could be detected in their blood even months after completing the vaccination program. It is interesting that two of these patients (#9 and #13), both with renal cell carcinoma, had been successfully treated in the past with IL2 or IFNα, confirming the sensitivity of this cancer to immunotherapy. In contrast, none of 11 patients with renal cancer who were vaccinated with the dominant TERT₅₄₀ peptide had an objective clinical response, even when they developed a peptide-specific immune response (Parkhurst, Riley et al. 2004).

[0058] In conclusion, this study demonstrates that vaccination of advanced cancer patients with the optimized cryptic TERT₅₇₂Y peptide is safe and induces an antitumor immunity in more than 90% of patients. This is the first clinical confirmation that cryptic peptides are promising candidates for cancer immunotherapy.

Example 2

In Vitro Selection and Amplification of CTLs with a High Avidity for the Native Cryptic Peptide

2.1. Materials and Methods

Peptides

[0059] The peptides TERT₉₈₈Y (YLQVNSLQTV, SEQ ID No: 4), TERT₉₈₈ (DLQVNSLQTV, SEQ ID No: 3), MAGE-A₂₄₈V9 (YLEYRQVPV, SEQ ID No: 6) and MAGE-A₂₄₈D9 (YLEYRQVPD, SEQ ID No: 5) have been produced by Epytop (Nimes, France).

Animals and Cells

[0060] The HLA-A*0201 transgenic HHD mice and the murine RMAS/HHD tumor cells were previously described (Pascolo, Bervas et al. 1997).

Generation of CTL in HHD Mice

[0061] HHD mice were injected subcutaneously with 100 μg of nonamer peptides emulsified in incomplete Freund's adjuvant (IFA) in the presence of 150 μg of the I-Ab restricted HBVcore128 T-helper epitope. Spleen cells (5×10⁷ cells in 10 ml) from immunized HHD mice were stimulated in vitro with peptide (10 μM) in RPMI1640+10% FCS for five days. The CTL lines were established by weekly re-stimulation in vitro with irradiated spleen cells in the presence of peptide and 50 U/ml IL-2 (Proleukin, Chiron Corp., Emeryville, Calif.).

Cytotoxic Assay

[0062] Murine RMAS/HHD cells were used as targets for cytotoxicity as described (Tourdot, Scardino et al. 2000). Briefly, 2.5×10³ 51Cr-labeled targets were pulsed with increasing doses (0.00001-10 μM) of peptides at 37° C. for 60 min. Effector cells in 100 μl were then added and incubated at 37° C. for 4 hours. After incubation, 100 μl of supernatant were collected and radioactivity was measured in a gamma counter. The specific lysis was determined as:

Lysis=(Experimental Release-Spontaneous Release)/(Maximal Release-Spontaneous Release).

CTL avidity is defined as the peptide concentration that gives half the maximal lysis. Hence, the lower the measured avidity (in nM), the higher the avidity of the CTLs.

In Vivo Tumor Protection Assay

[0063] HHD mice were vaccinated with 100 μg of peptide emulsified in IFA in the presence of 150 μg of the 1 Ab restricted HBVcore128 epitope once and then again two weeks later. One week after the second vaccination they were challenged subcutaneously with 2×104 EL4/HHD cells. Survival was recorded every two days.

2.2. Results

[0064] Results Obtained with a Cryptic Epitope from the TERT Antigen

[0065] HHD mice were immunized with the optimized cryptic TERT₉₈₈Y peptide. Eleven days later, spleen cells from vaccinated mice were pooled and in vitro serially stimulated with 10 μM of either TERT₉₈₈Y or the native cryptic TERT₉₈₈ peptides in the presence of 50 IU/ml of IL2. Stimulations were repeated every week. After the first, third and sixth in vitro stimulation, CTL lines were tested for their avidity for the native TERT₉₈₈ peptide in a classical ⁵¹Cr release cytotoxicity assay (Table 5).

TABLE-US-00005 TABLE 5 Avidity of CTL lines for the native TERT₉₈₈ peptide, established from TERT₉₈₈Y primed spleen cells in vitro stimulated with either TERT₉₈₈Y or TERT₉₈₈ peptides Peptide used for No of in vitro in vitro CTL line avidity stimulations stimulation (nM) 1 TERT₉₈₈ 170 TERT₉₈₈Y 300 3 TERT₉₈₈ 70 TERT₉₈₈Y 500 6 TERT₉₈₈ 3 TERT₉₈₈Y 600

Results Obtained with a Cryptic Epitope from the MAGE Antigen

[0066] HHD mice were immunized with the optimized MAGE-A₂₄₈V9 peptide, corresponding to the cryptic MAGE-A₂₄₈D9 (both described in WO03083124). Eleven days later, spleen cells from vaccinated mice were pooled and in vitro serially stimulated with 10 μM of either MAGE-A₂₄₈V9 or the native cryptic MAGE-A₂₄₈D9 peptides in the presence of 50 IU/ml of IL2. Stimulations were repeated every week. After the first, third and sixth in vitro stimulation, CTL lines were tested for their avidity for the native MAGE-A₂₄₈D9 peptide in a classical ⁵¹Cr release cytotoxicity assay (Table 6).

TABLE-US-00006 TABLE 6 Avidity of CTL lines established from MAGE-A₂₄₈V9 primed spleen cells in vitro stimulated with either MAGE-A₂₄₈V9 or MAGE-A₂₄₈D9 peptides Peptide used for No of in vitro the in vitro stimulations stimulation CTL avidity (nM) 1 MAGE-A₂₄₈D9 200 MAGE-A₂₄₈V9 400 3 MAGE-A₂₄₈D9 40 MAGE-A₂₄₈V9 450 6 MAGE-A₂₄₈D9 0.8 MAGE-A₂₄₈V9 320

2.3. Conclusion

[0067] Vaccination with optimized cryptic peptides recruits a CTL repertoire that contains cells with high avidity for the native cryptic peptide. These high avidity CTL can be in vitro selected and amplified by stimulation with the native rather than with the optimized cryptic peptide.

Example 3

In Vivo Selection of CTLs with High Avidity by Boosting with the Native Peptide

3.1. Materials and Methods

[0068] The same materials and methods as in Example 2 were used.

3.2. Results

[0069] HHD mice were vaccinated with the optimized cryptic TERT₅₇₂Y peptide described above. Fifteen days later, they were boosted with either the same optimized or the native cryptic TERT₅₇₂ peptide. Seven days after the boost, their spleen cells were in vitro stimulated with 10 μM of the TERT₅₇₂. CTL generated after one cycle of in vitro stimulation were tested for their avidity for TERT₅₇₂. Table 7 presents results from six individual mice.

TABLE-US-00007 TABLE 7 Avidity of CTL generated in HHD mice primed with the optimized cryptic TERT₅₇₂Y peptide and boosted with either the same optimized or the native TERT₅₇₂ peptide. Mouse 1st vaccination 2nd vaccination CTL avidity (nM) 1 TERT₅₇₂Y TERT₅₇₂Y 350 2 TERT₅₇₂Y TERT₅₇₂Y 700 3 TERT₅₇₂Y TERT₅₇₂Y 650 1 TERT₅₇₂Y TERT₅₇₂ 110 2 TERT₅₇₂Y TERT₅₇₂ 190 3 TERT₅₇₂Y TERT₅₇₂ 70

3.3. Conclusion

[0070] In vivo priming with the optimized cryptic peptides recruits a repertoire containing CTL with high avidity for the native peptide. These high avidity CTLs can be in vivo selected and amplified by boosting with the native rather than with the optimized peptide.

Example 4

Tumor Immunity in HHD Mice

4.1. Materials and Methods

[0071] The same materials and methods as in Example 2 were used.

[0072] An additional peptide, named gp100₁₅₄, was also used: KTWGQYWQV (SEQ ID NO: 8).

4.2. Results

[0073] HHD mice were vaccinated with the optimized cryptic TERT₅₇₂Y and TERT₉₈₈Y peptides and fifteen days later boosted with either the same optimized or the corresponding native cryptic peptide. Ten days after the boost, mice were challenged with EL4/HHD tumor cells and monitored for tumor growth and survival. Mice primed and boosted with the gp100₁₅₄ peptide were used as negative controls (Table 8). 100% of control mice died by day 43 post-challenge. 17% of mice primed and boosted with the optimized peptides and 50% of mice primed with the optimized and boosted with the native peptide were definitively protected against tumor.

TABLE-US-00008 TABLE 8 Survival of HHD mice primed with the optimized and boosted with either the same optimized or the corresponding native peptides. Survival post- Prime Boost challenge (days) Gp100₁₅₄ Gp100₁₅₄ 41 40 39 39 43 41 TERT₅₇₂Y TERT₅₇₂Y 31 40 40 40 200+ 45 TERT₅₇₂Y TERT₅₇₂ 200+ 200+ 32 35 200+ 40 TERT₉₈₈Y TERT₉₈₈Y 200+ 40 40 40 43 43 TERT₉₈₈Y TERT₉₈₈ 39 40 41 200+ 200+ 200+

4.3. Conclusion

[0074] Tumor immunity is much more efficient in mice primed with the optimized and boosted with the native peptide than in mice primed and boosted with the same optimized peptide.

REFERENCES

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Sequence CWU 1

1

9219PRTArtificialTERT-572 1Arg Leu Phe Phe Tyr Arg Lys Ser Val 1 5 29PRTArtificialTERT-572Y1 2Tyr Leu Phe Phe Tyr Arg Lys Ser Val 1 5 310PRTArtificialTERT-988 3Asp Leu Gln Val Asn Ser Leu Gln Thr Val 1 5 10 410PRTArtificialTERT-988Y1 4Tyr Leu Gln Val Asn Ser Leu Gln Thr Val 1 5 10 59PRTArtificialMAGE-A-248D9 5Tyr Leu Glu Tyr Arg Gln Val Pro Asp 1 5 69PRTArtificialMAGE-A-248V9 6Tyr Leu Glu Tyr Arg Gln Val Pro Val 1 5 79PRTArtificialMAGE-A-248G9 7Tyr Leu Glu Tyr Arg Gln Val Pro Gly 1 5 89PRTArtificialGp100-154 8Lys Thr Trp Gly Gln Tyr Trp Gln Val 1 5 99PRTArtificialGp100-154Y1 9Tyr Thr Trp Gly Gln Tyr Trp Gln Val 1 5 109PRTArtificialGp100-154M155 10Lys Met Trp Gly Gln Tyr Trp Gln Val 1 5 119PRTArtificialFluM-58 11Gly Ile Gly Leu Phe Val Phe Thr Leu 1 5 129PRTArtificialFluM-58Y1 12Tyr Ile Gly Leu Phe Val Phe Thr Leu 1 5 139PRTArtificialHIVgag-76 13Ser Leu Tyr Asn Thr Val Ala Thr Leu 1 5 149PRTArtificialHIVgag-76Y1 14Tyr Leu Tyr Asn Thr Val Ala Thr Leu 1 5 159PRTArtificialHBVpol-575 15Phe Leu Leu Ser Leu Gly Ile His Leu 1 5 169PRTArtificialHBVpol-575Y1 16Tyr Leu Leu Ser Leu Gly Ile His Leu 1 5 1710PRTArtificialHBVpol-765 17Leu Leu Gly Cys Ala Ala Asn Trp Ile Leu 1 5 10 1810PRTArtificialHBVpol-765Y1 18Tyr Leu Gly Cys Ala Ala Asn Trp Ile Leu 1 5 10 199PRTArtificialMart-1-27 19Ala Ala Gly Ile Gly Ile Leu Thr Val 1 5 209PRTArtificialMart-1-27Y1 20Tyr Ala Gly Ile Gly Ile Leu Thr Val 1 5 2110PRTArtificialMart-1-26 21Glu Ala Ala Gly Ile Gly Ile Leu Thr Val 1 5 10 2210PRTArtificialMart-1-26L27 22Glu Leu Ala Gly Ile Gly Ile Leu Thr Val 1 5 10 2310PRTArtificialGp100-177 23Ala Met Leu Gly Thr His Thr Met Glu Val 1 5 10 2410PRTArtificialGp100-177Y1 24Tyr Met Leu Gly Thr His Thr Met Glu Val 1 5 10 259PRTArtificialGp100-178 25Met Leu Gly Thr His Thr Met Glu Val 1 5 269PRTArtificialGp100-178Y1 26Tyr Leu Gly Thr His Thr Met Glu Val 1 5 2710PRTArtificialGp100-570 27Ser Leu Ala Asp Thr Asn Ser Leu Ala Val 1 5 10 2810PRTArtificialGp100-570Y1 28Tyr Leu Ala Asp Thr Asn Ser Leu Ala Val 1 5 10 298PRTArtificialGp100-209 29Thr Asp Gln Val Pro Phe Ser Val 1 5 308PRTArtificialGp100-209Y1 30Tyr Asp Gln Val Pro Phe Ser Val 1 5 318PRTArtificialGp100-209M210 31Tyr Met Gln Val Pro Phe Ser Val 1 5 3210PRTArtificialGp100-476 32Val Leu Tyr Arg Tyr Gly Ser Phe Ser Val 1 5 10 3310PRTArtificialGp100-476Y1 33Tyr Leu Tyr Arg Tyr Gly Ser Phe Ser Val 1 5 10 3410PRTArtificialGp100-457 34Leu Leu Asp Gly Thr Ala Thr Leu Arg Leu 1 5 10 3510PRTArtificialGp100-457Y1 35Tyr Leu Asp Gly Thr Ala Thr Leu Arg Leu 1 5 10 369PRTArtificialHER-2/neu-799 36Gln Leu Met Pro Tyr Gly Cys Leu Leu 1 5 379PRTArtificialHER-2/neu-799Y1 37Tyr Leu Met Pro Tyr Gly Cys Leu Leu 1 5 389PRTArtificialHER-2/neu-369 38Lys Ile Phe Gly Ser Leu Ala Phe Leu 1 5 399PRTArtificialHER-2/neu-369Y1 39Tyr Ile Phe Gly Ser Leu Ala Phe Leu 1 5 409PRTArtificialHER-2/neu-789 40Cys Leu Thr Ser Thr Val Gln Leu Val 1 5 419PRTArtificialHER-2/neu-789Y1 41Tyr Leu Thr Ser Thr Val Gln Leu Val 1 5 428PRTArtificialHER-2/neu-48 42His Leu Tyr Gln Gly Cys Gln Trp 1 5 438PRTArtificialHER-2/neu-48Y1 43Tyr Leu Tyr Gln Gly Cys Gln Trp 1 5 4410PRTArtificialHER-2/neu-773 44Val Met Ala Gly Val Gly Ser Pro Tyr Val 1 5 10 4510PRTArtificialHER-2/neu-773Y1 45Tyr Met Ala Gly Val Gly Ser Pro Tyr Val 1 5 10 468PRTArtificialHER-2/neu-5 46Ala Leu Cys Arg Trp Gly Leu Leu 1 5 478PRTArtificialHER-2/neu-5Y1 47Tyr Leu Cys Arg Trp Gly Leu Leu 1 5 489PRTArtificialHER-2/neu-851 48Val Leu Val Lys Ser Pro Asn His Val 1 5 499PRTArtificialHER-2/neu-851Y1 49Tyr Leu Val Lys Ser Pro Asn His Val 1 5 509PRTArtificialHER-2/neu-661 50Ile Leu Leu Val Val Val Leu Gly Val 1 5 519PRTArtificialHER-2/neu-661Y1 51Tyr Leu Leu Val Val Val Leu Gly Val 1 5 529PRTArtificialHER-2/neu-650 52Pro Leu Thr Ser Ile Ile Ser Ala Val 1 5 539PRTArtificialHER-2/neu-650Y1 53Tyr Leu Thr Ser Ile Ile Ser Ala Val 1 5 549PRTArtificialHER-2/neu-466 54Ala Leu Ile His His Asn Thr His Leu 1 5 559PRTArtificialHER-2/neu-466Y1 55Tyr Leu Ile His His Asn Thr His Leu 1 5 569PRTArtificialHER-2/neu-402 56Thr Leu Glu Glu Ile Thr Gly Tyr Leu 1 5 579PRTArtificialHER-2/neu-402Y1 57Tyr Leu Glu Glu Ile Thr Gly Tyr Leu 1 5 589PRTArtificialHER-2/neu-391 58Pro Leu Gln Pro Glu Gln Leu Gln Val 1 5 599PRTArtificialHER-2/neu-391Y1 59Tyr Leu Gln Pro Glu Gln Leu Gln Val 1 5 609PRTArtificialHER-2/neu-971 60Glu Leu Val Ser Glu Phe Ser Arg Met 1 5 619PRTArtificialHER-2/neu-971Y1 61Tyr Leu Val Ser Glu Phe Ser Arg Met 1 5 629PRTArtificialHBVpol-28 62Leu Leu Asp Asp Glu Ala Gly Pro Leu 1 5 639PRTArtificialHBVpol-28Y1 63Tyr Leu Asp Asp Glu Ala Gly Pro Leu 1 5 649PRTArtificialHBVpol-594 64Pro Leu Glu Glu Glu Leu Pro Arg Leu 1 5 659PRTArtificialHBVpol-594Y1 65Tyr Leu Glu Glu Glu Leu Pro Arg Leu 1 5 669PRTArtificialHBVpol-985 66Asn Leu Gln Ser Leu Thr Asn Leu Leu 1 5 679PRTArtificialHBVpol-985Y1 67Tyr Leu Gln Ser Leu Thr Asn Leu Leu 1 5 689PRTArtificialEphA2-61 68Asp Met Pro Ile Tyr Met Tyr Ser Val 1 5 699PRTArtificialEphA2-61Y1 69Tyr Met Pro Ile Tyr Met Tyr Ser Val 1 5 7010PRTArtificialHER2-911 70Thr Val Trp Glu Leu Met Thr Phe Gly Ala 1 5 10 7110PRTArtificialHER2-911Y1V10 71Tyr Val Trp Glu Leu Met Thr Phe Gly Val 1 5 10 7210PRTArtificialHER4-911 72Thr Ile Trp Glu Leu Met Thr Phe Gly Gly 1 5 10 7310PRTArtificialHER1-911 73Thr Val Trp Glu Leu Met Thr Phe Gly Ser 1 5 10 749PRTArtificialHER2-722 74Lys Val Lys Val Leu Gly Ser Gly Ala 1 5 759PRTArtificialHER2-722Y1V9 75Tyr Val Lys Val Leu Gly Ser Gly Val 1 5 769PRTArtificialHER3-722 76Lys Leu Lys Val Leu Gly Ser Gly Val 1 5 779PRTArtificialHER4-722 77Arg Val Lys Val Leu Gly Ser Gly Ala 1 5 789PRTArtificialHER1-722 78Lys Ile Lys Val Leu Gly Ser Gly Ala 1 5 799PRTArtificialHER2-845 79Asp Leu Ala Ala Arg Asn Val Leu Val 1 5 809PRTArtificialHER-845Y1 80Tyr Leu Ala Ala Arg Asn Val Leu Val 1 5 819PRTArtificialHER3-845 81Asn Leu Ala Ala Arg Asn Val Leu Leu 1 5 829PRTArtificialHER2-904 82Asp Val Trp Ser Tyr Gly Val Thr Val 1 5 839PRTArtificialHER-904Y1 83Tyr Val Trp Ser Tyr Gly Val Thr Val 1 5 849PRTArtificialHER4-904 84Asp Val Trp Ser Tyr Gly Val Thr Ile 1 5 859PRTArtificialHER2-933 85Asp Leu Leu Glu Lys Gly Glu Arg Leu 1 5 869PRTArtificialHER-933Y1 86Tyr Leu Leu Glu Lys Gly Glu Arg Leu 1 5 8710PRTArtificialHER1-933 87Ser Ile Leu Glu Leu Lys Gly Glu Arg Leu 1 5 10 8810PRTArtificialHER2-945 88Pro Ile Cys Thr Ile Asp Val Tyr Met Ile 1 5 10 8910PRTArtificialHER3-945 89Gln Ile Cys Thr Ile Asp Val Tyr Met Val 1 5 10 9010PRTArtificialHER-945Y1 90Tyr Ile Cys Thr Ile Asp Val Tyr Met Val 1 5 10 9110PRTArtificialHER4-945 91Pro Ile Cys Thr Ile Asp Val Tyr Met Val 1 5 10 9210PRTArtificialHER1-945 92Pro Ile Cys Thr Ile Asp Val Tyr Lys Ile 1 5 10

Claims

1. A vaccination kit, comprising at least one dose of a native peptide and at least one dose of an optimized immunogenic peptide derived from said native peptide, wherein said native and optimized peptides are selected from the group consisting of the following pairs of peptides: TERT572 (SEQ ID No: 1) and TERT572Y1 (SEQ ID No: 2); TERT988 (SEQ ID No: 3) and TERT988Y1 (SEQ ID No: 4); MAGE-A248D9 (SEQ ID No: 5) and MAGE-A248V9 (SEQ ID No: 6); MAGE-A248G9 (SEQ ID No: 7) and MAGE-A248V9 (SEQ ID No: 6); Gp100 154 (SEQ ID No: 8) and Gp100 154Y1 (SEQ ID No: 9); Gp100 154 (SEQ ID No: 8) and Gp100 154M155 (SEQ ID No: 10); FluM58 (SEQ ID No: 11) and FluM58Y1 (SEQ ID No: 12); HIVgag76 (SEQ ID No: 13) and HIVgag76Y1 (SEQ ID No: 14); HBVpol575 (SEQ ID No: 15) and HBVpol575Y1 (SEQ ID No: 16); HBVpol765 (SEQ ID No: 17) and HBVpol765Y1 (SEQ ID No: 18); Mart-127 (SEQ ID No: 19) and Mart-127Y1 (SEQ ID No: 20); Mart-126 (SEQ ID No: 21) and Mart-126L27 (SEQ ID No: 22); Gp100 177 (SEQ ID No: 23) and Gp100 177Y1 (SEQ ID No: 24); Gp100 178 (SEQ ID No: 25) and Gp100 178Y1 (SEQ ID No: 26); Gp100 570 (SEQ ID No: 27) and Gp100 570Y1 (SEQ ID No: 28); Gp100 209 (SEQ ID No: 29) and Gp100 209Y1 (SEQ ID No: 30); Gp100 209 (SEQ ID No: 29) and Gp100 209M210 (SEQ ID No: 31); Gp100 476 (SEQ ID No: 32) and Gp100 476Y1 (SEQ ID No: 33); Gp100 457 (SEQ ID No: 34) and Gp100 457Y1 (SEQ ID No: 35); HER-2/neu799 (SEQ ID No: 36) and HER-2/neu799Y1 (SEQ ID No: 37); HER-2/neu369 (SEQ ID No: 38) and HER-2/neu369Y1 (SEQ ID No: 39); HER-2/neu789 (SEQ ID No: 40) and HER-2/neu789Y1 (SEQ ID No: 41); HER-2/neu48 (SEQ ID No: 42) and HER-2/neu48Y1 (SEQ ID No: 43); HER-2/neu773 (SEQ ID No: 44) and HER-2/neu773Y1 (SEQ ID No: 45); HER-2/neu5 (SEQ ID No: 46) and HER-2/neu5Y1 (SEQ ID No: 47); HER-2/neu851 (SEQ ID No: 48) and HER-2/neu851Y1 (SEQ ID No: 49); HER-2/neu661 (SEQ ID No: 50) and HER-2/neu661Y1 (SEQ ID No: 51); HER-2/neu650 (SEQ ID No: 52) and HER-2/neu650Y1 (SEQ ID No: 53); HER-2/neu466 (SEQ ID No: 54) and HER-2/neu466Y1 (SEQ ID No: 55); HER-2/neu402 (SEQ ID No: 56) and HER-2/neu402Y1 (SEQ ID No: 57); HER-2/neu391 (SEQ ID No: 58) and HER-2/neu391Y1 (SEQ ID No: 59); HER-2/neu971 (SEQ ID No: 60) and HER-2/neu971Y1 (SEQ ID No: 61); HBVpol28 (SEQ ID No: 62) and HBVpol28Y1 (SEQ ID No: 63); HBVpol594 (SEQ ID No: 64) and HBVpol594Y1 (SEQ ID No: 65); HBVpol985 (SEQ ID No: 66) and HBVpol985Y1 (SEQ ID No: 67); EphA2 61 (SEQ ID No: 68) and EphA2 61Y1 (SEQ ID No: 69); HER2 911 (SEQ ID No: 70) and HER911Y1V10 (SEQ ID No: 71); HER4 911 (SEQ ID No: 72) and HER911Y1V10 (SEQ ID No: 71); HER1 911 (SEQ ID No: 73) and HER911Y1V10 (SEQ ID No: 71); HER2 722 (SEQ ID No: 74) and HER722Y1V9 (SEQ ID No: 75); HER3 722 (SEQ ID No: 76) and HER722Y1V9 (SEQ ID No: 75); HER4 722 (SEQ ID No: 77) and HER722Y1V9 (SEQ ID No: 75); HER1 722 (SEQ ID No: 78) and HER722Y1V9 (SEQ ID No: 75); HER2 845 (SEQ ID No: 79) and HER845Y1 (SEQ ID No: 80); HER3 845 (SEQ ID No: 81) and HER845Y1 (SEQ ID No: 80); HER2 904 (SEQ ID No: 82) and HER904Y1 (SEQ ID No: 83); HER4 904 (SEQ ID No: 84) and HER904Y1 (SEQ ID No: 83); HER2 933 (SEQ ID No: 85) and HER933Y1 (SEQ ID No: 86); HER1 933 (SEQ ID No: 87) and HER933Y1 (SEQ ID No: 86); HER2 945 (SEQ ID No: 88) and HER945Y1 (SEQ ID No: 90); HER3 945 (SEQ ID No: 89) and HER945Y1 (SEQ ID No: 90); HER4 945 (SEQ ID No: 91) and HER945Y1 (SEQ ID No: 90); and HER1 945 (SEQ ID No: 92) and HER945Y1 (SEQ ID No: 90), and wherein said vaccination kit further comprises a notice of use indicating that the kit is intended for performing a method of vaccinating a patient against a tumoral or viral antigen comprising a first step of vaccination with an optimized peptide cognate to a native peptide of said antigen, followed by a second step of vaccination with said native peptide, whereby the step of vaccination with the native peptide amplifies CTLs with high avidity for said native peptide.

2. The vaccination kit of claim 1, which comprises 2 or 3 doses of optimized peptide, and 3, 4, 5, 6 or up to 50 doses of native peptide.

3. The vaccination kit of claim 1, wherein each dose comprises 1 to 5 mg of peptide.

4. The vaccination kit of claim 1, wherein said vaccination doses are formulated for subcutaneous injection.

5. The vaccination kit of claim 1, wherein said vaccination doses are formulated for a human patient.

6. The vaccination kit of claim 1, wherein said native peptide is from a tumor antigen.

7. The vaccination kit of claim 1, wherein said native peptide is from a viral antigen.

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