Abstract:
The invention provides immunogenic peptides from the HPV type 16 E7 protein that comprise overlapping class I restricted T cell epitopes. Also disclosed are methods of administering DNA molecules encoding these peptides to a host mammal.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to treatment of human papilloma virus (HPV) infection. 
     Papilloma viruses are non-enveloped DNA viruses with a double stranded circular genome of approximately 8,000 bp. Over 75 types of human papilloma viruses (HPV) have been typed at the DNA level, and these can be broadly grouped into families on the basis of their tissue tropism. 
     Histologic, molecular, and epidemiologic evidence have implicated some HPV strains in cervical dysplasia and cervical cancer. Many studies support the view that most moderate and severe cervical intraepithelial neoplasias (CIN) contain HPV DNA which is exclusively detected in the histologically abnormal epithelium of these lesions. Persistent infection with HPV is believed to be the predominant risk factor for development of cervical carcinoma. HPV DNA is readily found in episomal form within cells exhibiting a cytopathic effect, while the HPV DNA is found integrated within the chromosomes of cells associated with most high grade precancerous lesions and cancer. Approximately 23 HPV types are commonly found in anogenital screening programs, but only 10-15 are associated with progressive disease. Type 16 is the type most commonly found in cervical cancer tissue. 
     Papillomaviruses contain nine open reading frames. HPV genes with transforming properties have been mapped to open reading frames E6 and E7. Substantial biochemical work has demonstrated that the HPV E6 protein inactivates the protein p53, whereas the E7 protein interferes with retinoblastoma (Rb) protein function. Since p53 and Rb are tumor-suppressor proteins which function as cell division inhibitors, their inactivation by E6 and E7 leads the cell to enter into S phase of the cell cycle. Expression of E6 and E7 is sufficient to immortalize some primary cell lines, and blocking E6 or E7 function has been shown to reverse the transformed state. 
     SUMMARY OF THE INVENTION 
     The invention is based on the discovery that a 13 amino acid peptide from the HPV strain 16 E7 protein that contains two overlapping class I HLA-A2 binding, T cell epitopes can induce a CTL response in an animal. Accordingly, the invention includes an immunogenic peptide having within its sequence two class I MHC-binding epitopes from a human papillomavirus (HPV) protein, and which has a length of less than 19 amino acids and includes the sequence of Leu Met Gly Thr Leu Gly Ile Val Cys Pro Ile Cys (SEQ ID NO:16) (hereinafter &#34;immunogenic peptide&#34;). The immunogenic peptide can optionally include sequences in addition to those derived from the E7 protein. 
     The immunogenic peptide can have the sequence of Leu Leu Met Gly Thr Leu Gly Ile Val Cys Pro Ile Cys (SEQ ID NO:3) or Xaa Leu Met Gly Thr Leu Gly Ile Val Cys Pro Ile Cys, Xaa being Ala, Ser, Arg, Lys, Gly, Gln, Asp, or Glu (SEQ ID NO:19), e.g., Ala Leu Met Gly Thr Leu Gly Ile Val Cys Pro Ile Cys (SEQ ID NO:4). 
     The invention also includes a polypeptide having the sequence of a first peptide linked to a second peptide by a peptide bond. The first peptide (which can be at the carboxy terminus or the amino terminus of the second peptide, so long as it functions in that site) is a peptide which controls intracellular trafficking of a peptide to which it is attached, and the second peptide is the immunogenic peptide described above. The polypeptide may optionally be modified to introduce an amino acid substitution at the junction between the first and second peptides to promote cleavage of the first and second peptides by a signal peptidase. 
     The trafficking peptides can be any recognized signal sequence, e.g. a signal sequence from the adenovirus E3 protein. A preferred trafficking peptide is the signal peptide of HLA-DRα, Met Ala Ile Ser Gly Val Pro Val Leu Gly Phe Phe Ile Ile Ala Val Leu Met Ser Ala Gln Glu Ser Trp Ala (SEQ ID NO:18). 
     The invention in addition includes a therapeutic composition containing the immunogenic peptide described above, and a pharmaceutically acceptable carrier. The polypeptide can optionally be formulated in a microparticle, a liposome or an immune-stimulating complex (ISCOM) (which may contain saponin alone as the active ingredient), or any other vehicle suitable for delivering into subjects the immunogenic peptides of the invention. When a microparticle is used, it preferably has a polymeric matrix that is a copolymer such as poly-lactic-co-glycolic acid (PLGA). 
     An MHC class I-mediated immune response in a mammal can be elicited by administering the immunogenic peptide to a mammal, e.g., a human, non-human primate, dog, cat, rabbit, cow, mouse, rat, guinea pig, or hamster, that has an MHC molecule that binds to the immunogenic peptide. The immunogenic peptide can be administered as part of a microparticle, liposome, or ISCOM, or in solution. 
     Another way to administer the peptide utilizes a nucleic acid, e.g., an expression vector, comprising a coding sequence encoding the immunogenic peptide. The nucleic acid can optionally encode a signal sequence linked to the immunogenic peptide, as described above. When the nucleic acid encodes such a signal sequence, it is preferred that it encodes the signal sequence from HLA-DRα (SEQ ID NO:18). In such a case, the immunogenic peptide can have the sequence, for example, of SEQ ID NO:4 or SEQ ID NO:3. Preferably, the nucleic acid does not include sequences from a viral genome that would render the nucleic acid infectious, and does not encode an intact E7 protein. 
     The nucleic acid described above can be included in a plasmid, optionally provided in a microparticle that also includes a polymeric matrix. In preferred embodiments, the polymeric matrix consists essentially of a copolymer of PLGA. The microparticle preferably has a mean diameter of, e.g., 0.02 to 20 microns, or less than about 11 microns. 
     Also within the invention is a cell containing the plasmid of the invention. The cell can, e.g., be a B cell or other antigen presenting cell (APC). The cell may be cultured or otherwise maintained under conditions permitting expression of the peptide from the plasmid encoding it. 
     The nucleic acid and plasmid of the invention are useful in a method of inducing an MHC class I-mediated immune response in a mammal, e.g., a human, by administering the above-described plasmid to the mammal, e.g., as &#34;naked DNA&#34;. The mammal may be at risk for, or suffer from, HPV infection, cervical dysplasia, and/or cervical cancer. The nucleic acids and plasmids of the invention can also be incorporated into microparticles, liposomes, ISCOMS, or any other suitable delivery vehicle as described above. 
     The invention further includes a plasmid having a sequence essentially identical to that of pBIOTOPE HPV  (SEQ ID NO:7), or a microparticle consisting essentially of a PLGA polymeric matrix and the pBIOTOPE HPV  plasmid, as well as methods of inducing an MHC class I-mediated immune response in a mammal by administering either the plasmid alone, or the plasmid incorporated into such a microparticle, to the mammal. 
     By a &#34;substantially pure polypeptide&#34; is meant a polypeptide which is separated from those components (proteins and other naturally-occurring organic molecules) which naturally accompany it. Typically, the polypeptide is substantially pure when it constitutes at least 60%, by weight, of the protein in the preparation. Preferably, the protein in the preparation consists of at least 75%, more preferably at least 90%, and most preferably at least 99%, by weight, of an immunogenic peptide. 
     Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The preferred methods and materials for practicing the invention are described below, although other methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. In case of conflict, the present application, including definitions, will control. The materials, methods, and examples are illustrative only and not intended to be limiting. 
     Other features and advantages of the invention will be apparent from the following detailed description, and from the claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     FIG. 1 is a schematic drawing of the pBIOTOPE HPV  plasmid. 
    
    
     DETAILED DESCRIPTION 
     Three immunogenic peptides derived from the HPV type 16 E7 protein are shown in Table I. Peptide A2.1/4, Leu Leu Met Gly Thr Leu Gly Ile Val Cys Pro Ile Cys (SEQ ID NO:3), corresponds to amino acids 82-94 in the HPV Type 16 E7 protein and includes the overlapping sequences of peptides A2.1, Leu Leu Met Gly Thr Leu Gly Ile Val (SEQ ID NO:1), and A2.4, Thr Leu Gly Ile Val Cys Pro Ile Cys (SEQ ID NO:2). Thus, peptide A2.1/4 has at least two overlapping epitopes recognized by class I MHC restricted T cells. 
     
                       TABLE I______________________________________Amino acid sequences of conserved, class I-MHCbinding, TCR binding HPV strain 17 E7 peptides______________________________________A2.1      LLMGTLGIV       (SEQ ID NO: 1)A2.4      TLGIVCPIC       (SEQ ID NO: 2)A2.1/4    LLMGTLGIVCPIC   (SEQ ID NO: 3)______________________________________ 
    
     The peptides of the invention can be linked to a trafficking sequence that directs the peptides to a desired intracellular compartment. One such trafficking sequence is the HLA-DRα leader sequence (SEQ ID NO:18). In some cases it is desirable to modify the portion of the peptide spanning the trafficking sequence and the sequence encoding the HPV E7 antigenic peptide to facilitate processing, i.e., cleavage, by the signal peptidase. Recognition sequences for signal peptides are described in Von Heijne, NAR 14:4683, 1986. 
     Standard techniques can be used to construct a DNA encoding the antigenic peptide (see, e.g., the techniques described in WO 94/04171). The construct may include additional sequences for enhancing expression in human cells, e.g., appropriate promoters, RNA stabilization sequences 5&#39; and 3&#39; to the coding sequence, introns (which can be placed at any location within encoded sequence), and poly(A) addition sites, as well as an origin of replication and selectable markers enabling the constructs to replicate and be selected for in prokaryotic and/or eukaryotic hosts. 
     An example of a DNA sequence encoding an immunogenic HPV E7 antigen is the pBIOTOPE HPV  construct (SEQ ID NO:7), which is shown schematically in FIG. 1. This plasmid contains a minigene (SEQ ID NO: 5) at positions 3290-3413. The minigene encodes the HLA-DRα trafficking peptide linked to 12 residues of the A2.1/4 peptide. In the peptide encoded by the minigene, an alanine has been substituted for the amino terminal leucine in the A2.1/4 peptide in order to facilitate cleaving of the trafficking peptide from the immunogenic peptide by a signal peptidase. The BIOTOPE HPV  construct also carries the immediate early promoter of human cytomegalovirus (CMV) at positions 2619-3315, and RNA stabilization sequences (RST) derived from the Xenopus laevis β-globin gene flanking the minigene (positions 3219-3279 and 3426-3624). To maximize export from the nucleus, the pre-mRNA expressed from the plasmid contains a chimeric intron between the coding sequence of the minigene and the SV40 polyadenylation site. 
     Once in the cytoplasm of the cell, the mRNA transcribed from the minigene is translated to produce a 40 amino acid hybrid peptide. The first two amino acids are methionine and aspartic acid (derived from vector sequences), and the next 38 amino acids correspond to Met Ala Ile Ser Gly Val Pro Val Leu Gly Phe Phe Ile Ile Ala Val Leu Met Ser Ala Gln Glu Ser Trp Ala Ala Leu Met Gly Thr Leu Gly Ile Val Cys Pro Ile Cys (SEQ ID NO:6). The amino-terminal 25 amino acids of the 38-residue portion are identical in sequence to the non-polymorphic HLA-DRα chain gene leader sequence (SEQ ID NO:18). The last 13 amino acids have the sequence Ala Leu Met Gly Thr Leu Gly Ile Val Cys Pro Ile Cys(SEQ ID NO:4), which is the A2.1/4 peptide described above, but with an alanine residue substituted for the amino terminal leucine residue. Also within the plasmid is a kanamycin resistance gene (positions 519-1313), which is driven by the SV40 early promoter (positions 131-484) and which has a thymidine kinase (TK) polyadenylation site (positions 1314-1758). 
     The peptides and nucleic acids of the invention can be used as vaccines prophylactically or therapeutically in subjects known to be infected by HPV, suspected of being infected by HPV, or likely to become infected by HPV. Other suitable subjects include those displaying symptoms of, or likely to develop, HPV-associated conditions. The immunogenic peptides, and nucleic acids encoding these peptides, can be used as vaccines in preventing or treating conditions associated with infections of HPV strain 16, e.g., bowenoid papulosis, cervical dysplasia, cervical cancer, and vulval cancer. They can also be used to treat conditions associated with other HPV strains, especially those associated with HPV strains 18, 45, 6, 11, 35 and 31, which have regions of homology to the peptide of SEQ ID NO:3. These conditions include, e.g., exophytic condyloma (HPV strains 6 and 11), flat condyloma, especially of the cervix (HPV strains 6, 11, 16, 18, and 31), giant condyloma (HPV strains 6 and 11), cervical cancer (HPV strains 18, 31, and 33, in addition to HPV strain 16), respiratory and conjunctival papillomas (HPV 6 and 11), and infection with genital-tract HPVs (HPV 6, 11, and 16). 
     The immunogenic peptides or nucleic acids encoding the peptides can administered alone or in combination with other therapies known in the art, e.g., chemotherapeutic regimens, radiation, and surgery, to treat HPV infections, or diseases associated with HPV infections. In addition, the peptides and nucleic acids of the invention can be administered in combination with other treatments designed to enhance immune responses, e.g., by co-administration with adjuvants or cytokines (or nucleic acids encoding cytokines) as is well known in the art. 
     Delivery of Immunogenic Peptides and Nucleic Acids Encoding Immunogenic Peptides 
     The delivery systems of the invention may be used to deliver, into appropriate cells, peptides, or DNA constructs which express peptides, intended to stimulate an immune response against HPV. An advantage of DNA delivery is that the antigenic peptide is produced inside the target cell itself, where the interaction with a class I MHC molecule to which the immunogenic peptide binds is kinetically favored. This is in contrast to standard vaccine protocols which do not specifically direct antigenic peptides to class I molecules. In addition, the immune response stimulated by DNA vaccines of the invention is likely to be limited to a T cell mediated response, in contrast to standard vaccine protocols which result in a more generalized immune response. 
     The immunogenic peptides, or nucleic acids encoding the peptides, can be administered using standard methods, e.g., those described in Donnelly et al., J. Imm. Methods 176:145, 1994, and Vitiello et al., J. Clin. Invest. 95:341, 1995. Peptides and nucleic acids of the invention can be injected into subjects in any manner known in the art, e.g., intramuscularly, intravenously, intraarterially, intradermally, intraperitoneally, intranasally, or subcutaneously, or they can be introduced into the gastrointestinal tract or the respiratory tract, e.g., by inhalation of a solution or powder containing the microparticles. Administration can be local (e.g., at the cervix or other site of infection) or systemic. 
     It is expected that a dosage of approximately 0.1 to 100 μmoles of the polypeptide, or of about 1 to 200 μg of DNA, would be administered per kg of body weight. Where the patient is an adult human, vaccination regimens can include, e.g., intramuscular or subcutaneous administrations of 10-100 μg of pBIOTOPE HPV  DNA when delivered in a microparticle, or of about 100-1000 μg of naked pBIOTOPE HPV  DNA, repeated 3-6 times. Of course, as is well known in the medical arts, dosage for any given patient depends upon many factors, including the patient&#39;s size, body surface area, age, the particular compound to be administered, sex, time and route of administration, general health, and other drugs being administered concurrently. Determination of optimal dosage is well within the abilities of a pharmacologist of ordinary skill. 
     Other standard delivery methods, e,g, biolistic transfer, or ex vivo treatment, can also be used. In ex vivo treatment, e.g., antigen presenting cells (APCs), dendritic cells, peripheral blood mononuclear cells, or bone marrow cells, can be obtained from a patient or an appropriate donor and activated ex vivo with the immunogenic compositions, and then returned to the patient. 
     Microparticle Delivery of Synthetic Immunogenic Peptides or Plasmids Encoding Immunogenic Peptides 
     Microparticles, including those described in co-owned U.S. Ser. No. 08/787,547, can be used as vehicles for delivering macromolecules such as DNA, RNA, or polypeptides into cells. They contain macromolecules enclosed in a polymeric matrix. Microparticles act to maintain the integrity of the macromolecule e.g., by maintaining enclosed DNA in a nondegraded state. 
     The polymeric matrix can be a biodegradable co-polymer such as poly-lactic-co-glycolic acid. Microparticles can be used in particular to maximize delivery of DNA molecules into a subject&#39;s phagocytotic cells. Alternatively, the microparticles can be injected or implanted in a tissue, where they form a deposit. As the deposit breaks down, the nucleic acid is released gradually over time and taken up by neighboring cells (including APCs) as free DNA. 
     Liposomal Delivery of Synthetic Immunogenic Peptides or Plasmids Encoding Immunogenic Peptides 
     The immunogenic peptides of the invention can be administered into subjects via liposomes using techniques that are well known in the art. For example, liposomes carrying immunogenic polypeptides or nucleic acids encoding immunogenic peptides are known to elicit CTL responses in vivo (Reddy et al., J. Immunol. 148:1585, 1992; Collins et al., J. Immunol. 148:3336-3341, 1992; Fries et al., Proc. Natl. Acad. Sci. U.S.A. 89:358, 1992; Nabel et al., Proc. Nat. Acad. Sci. (U.S.A.) 89:5157, 1992). 
     Delivery of Synthetic Immunogenic Peptides or Plasmids Encoding Immunogenic Peptides Using Saponin 
     The peptides and nucleic acids of the invention can be administered by using Immune Stimulating Complexes (ISCOMS), which are negatively charged cage-like structures of 30-40 nm in size formed spontaneously on mixing cholesterol and Quil A (saponin), or saponin alone. The peptides and nucleic acids of the invention can be co-administered with the ISCOMS, or can be administered separately. 
     Protective immunity has been generated in a variety of experimental models of infection, including toxoplasmosis and Epstein-Barr virus-induced tumors, using ISCOMS as the delivery vehicle for antigens (Mowat et al., Immunology Today 12:383-385, 1991). Doses of antigen as low as 1 μg encapsulated in ISCOMS have been found to produce class I mediated CTL responses, where either purified intact HIV-1-IIIB gp 160 envelope glycoprotein or influenza hemagglutinin is the antigen (Takahashi et al., Nature 344:873-875, 1990). 
     Measuring Responses of the Immune System and of HPV Virus Infections to the Immunogenic Peptides or Nucleic Acids Encoding the Immunogenic Peptides 
     The ability of immunogenic peptides, or nucleic acids encoding the same, to elicit an immune response can be assayed by using methods for measuring immune responses that are well known in the art. For example, the generation of cytotoxic T cells can be demonstrated in a standard  51  Cr release assay. Standard assays, such as ELISA or ELISPOT, can also be used to measure cytokine profiles attributable to T cell activation. 
     Standard methodologies, e.g., cytologic, colposcopic and histological evaluations, can also be used to evaluate the effects of immunogenic peptides, and of nucleic acids encoding the immunogenic peptides, on papilloma virus-associated lesions, or on papilloma virus levels generally. 
     The following are examples of the practice of the invention. They are not to be construed as limiting the scope of the invention in anyway. 
     EXAMPLES 
     As described in the Examples below, experimental models were chosen to demonstrate the generation of vigorous CTL responses to plasmids encoding the immunogenic peptides of the invention, e.g., pBIOTOPE HPV . 
     Initial screening of HPV peptide sequences was performed by assessing binding affinity to the human class I HLA-A2 molecule. This was done by measuring the changes in circular dichroism (CD) as the receptor/ligand complex &#34;melted&#34;. Examples of this type of screening are shown in Example 1. of particular interest in Example 1 was the hybrid peptide A2.1/4, which contains two known epitopes. 
     Using a murine transgenic model, plasmids containing minigenes encoding these peptides were evaluated for their ability to generate HLA-A2 restricted CTLS (Examples 2 and 3). CTL activity, as measured using human target cells labeled with HPV peptides, was significantly increased over control targets for both the plasmids encoding A2.4 and A2.1/4, including the pA2.4 plasmid delivered in a PLGA microparticle. 
     Example 1 
     Peptides Derived from HPV Strain 16 E7 Protein Bind Purified HLA-A*0201 With High Affinity 
     To determine if peptides A2.1 (SEQ ID NO:1), A2.2 (SEQ ID NO:17), A2.4 (SEQ ID NO:2) and A2.1/4 (SEQ ID NO:3) bind with biological affinity to the human class I molecule HLA-A2, recombinant HLA-A2 was produced in E. coli and refolded in the presence of the HPV-derived peptides and purified human β 2  -microglobulin. The resulting peptide-HLA complexes were then further purified by HPLC. To determine the precise thermokinetic interaction energy between receptor and ligand, each complex was &#34;melted&#34; while its structure was monitored by circular dichroism. The temperature required to &#34;melt&#34; the complex is an accurate indication of the affinity between receptor and ligand. 
     The results of the binding studies are shown in Table II. 
     
                       TABLE II______________________________________Peptides binding HLA-A2 moleculesNAME    Amino Acid Sequence                     IC.sub.50.sup.¤                             Tm.sup.♦______________________________________A2.1    SEQ ID NO:1        8      47.8A2.2     SEQ ID NO:17      49     52.5A2.4    SEQ ID NO:2       153     41.5A2.1/4  SEQ ID NO:3       ND      41.0______________________________________ .sup.¤ IC.sub.50 represents the amount (nM) of peptide required for 50% inhibition of binding of a radiolabeled standard peptide to HLAA*0201 measured in a molecular binding assay. .sup.♦ Values represent the temperature in degrees Celsius at which 50% of the refolded complexes are melted. HLAA2 will not refold in the absence of a peptide ligand of sufficient affinity. 
    
     Of particular interest is a hybrid peptide A2.1/4, which contains two known overlapping epitopes, A2.1 and A2.4, each of which is presented by HLA-A2 positive human cervical tumor cells expressing the HPV 16 E7 protein (Ressing et al., J. Immunology 154:5934, 1995). Of the peptides studied, A2.4 is predicted to be the most capable of eliciting cross reactive immune responses between HPV strains. Moreover, the hybrid peptide generates both the A2.1 and A2.4 peptides; administration of pBIOTOPE HPV  to mice was found to generate T cell responses to both immunogenic peptides. 
     Example 2 
     Induction of HPV-Specific CTL in HLA-Transgenic Mice Immunized With Intramuscular Injections of a Plasmid Encoding the HPV Strain 16 Derived A2.4 Peptide 
     To demonstrate that a plasmid encoding the A2.4 peptide (SEQ ID NO:2) produced HPV peptides in vivo and that CTL to these peptides were generated, a transgenic animal model was employed. The HLA-A2/K b  mouse line produces a hybrid MHC class I molecule. In this hybrid, the peptide binding domains (α1 and α2) are derived from the human class I molecule HLA-A*0201, whereas the domain (α3) which interacts with the CD8 co-receptor on CTLs is derived from the murine class I molecule K b . The resulting animal is capable of responding to immunogens which contain HLA-A2 restricted epitopes and of generating murine CTLs that recognize human target cells expressing HLA-A2 (Vitiello et al., J. Exp. Med. 173:1007, 1991). 
     6-8 week old HLA-A2/K b  females were immunized with either a plasmid encoding the A2.4 peptide having the amino terminal leucine replaced with an alanine residue, or with a null vector. Injections were performed with 50 μg of plasmid DNA injected as &#34;naked DNA&#34; (that is, with no liposome, microparticle, or other carrier) into each anterior tibialis muscle. A booster immunization was performed 14 days after the first immunization, and a second booster immunization was performed 14 days after the first boost. Ten days following the third immunization, splenocytes were harvested and stimulated in vitro with syngeneic lipopolysaccharide (LPS) blasts which had been incubated with the synthetic A2.4 peptide. After 4 days of co-culture, CTL activity was measured on human targets labeled with HPV peptides (Table III). 
     
                       TABLE III______________________________________Lysis of Human Cells Labeled with HPV-derivedPeptides by Murine CTL from HLA-Transgenic MiceImmunized with Plasmid Encoding an A2.4 peptide.IMMUNOGEN   % LYSIS OF TARGET CELLS*______________________________________pVA2.4      28.7 ± 0.7*Vector       6.8 ± 2.9*______________________________________ *Data are reported as the mean lysis values at 100:1 effector to target ratio. Error is reported as the standard deviation; p = 0.05 by Students ttest. 
    
     Mice immunized with a plasmid encoding the A2.4 peptide generate CTL that lyse human targets expressing HLA-A2 and the appropriate HPV peptide. This response is significantly greater than that achieved by immunization with null vector DNA alone. 
     Example 3 
     Plasmid DNA Encoding the A2.1/4 Peptide Delivered to Mice in PLGA Microparticles Elicits CTL Responses 
     6-8 week old HLA-A2/K b  females were immunized intraperitoneally one time with 2-5 μg of PLGA microparticles containing plasmid pBIOTOPE HPV . Seven days following the immunization, splenocytes were harvested and in vitro stimulated with IL-2. After 2 days, CTL activity was measured on human targets labeled with HPV peptides (HPV(+)), or lacking HPV peptide (HPV(-)), at an E:T ratio of 50:1 (Table IV). 
     
                       TABLE IV______________________________________Lysis of Human Cells Labeled with HPV-derived Peptides by Murine Splenocytes from HLA-Transgenic Mice Immunized with PLGA MicroparticlesContaining pBIOTOPE.sub.HPV       % LYSIS OF TARGET CELLSIMMUNOGEN     HPV(+)     HPV(-)______________________________________pBIOTOPE.sub.HPV         17.4 ± 2.8*                    3.9 ± 4.2*______________________________________ Data are reported as the mean lysis values from three individual measurements. *Error is reported as the standard deviation; p value &lt;0.05 as determined by the Students ttest. 
    
     Thus, mice immunized with PLGA microparticles containing pBIOTOPE HPV  generate CTL that lyse human targets expressing HLA-A2 and A2.1/4 peptide. 
     OTHER EMBODIMENTS 
     It is to be understood that while the invention has been described in conjunction with the detailed description thereof, that the foregoing description is intended to illustrate and not limit the scope of the appended claims. Other aspects, advantages, and modifications are within the scope of the following claims. 
     
         __________________________________________________________________________#             SEQUENCE LISTING- (1) GENERAL INFORMATION:-    (iii) NUMBER OF SEQUENCES: 19- (2) INFORMATION FOR SEQ ID NO:1:-      (i) SEQUENCE CHARACTERISTICS:#acids    (A) LENGTH: 9 amino     (B) TYPE: amino acid     (D) TOPOLOGY: linear-     (ii) MOLECULE TYPE: peptide-     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:1:- Leu Leu Met Gly Thr Leu Gly Ile Val  1               5- (2) INFORMATION FOR SEQ ID NO:2:-      (i) SEQUENCE CHARACTERISTICS:#acids    (A) LENGTH: 9 amino     (B) TYPE: amino acid     (D) TOPOLOGY: linear-     (ii) MOLECULE TYPE: peptide-     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:2:- Thr Leu Gly Ile Val Cys Pro Ile Cys  1               5- (2) INFORMATION FOR SEQ ID NO:3:-      (i) SEQUENCE CHARACTERISTICS:#acids    (A) LENGTH: 13 amino     (B) TYPE: amino acid     (D) TOPOLOGY: linear-     (ii) MOLECULE TYPE: peptide-     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:3:- Leu Leu Met Gly Thr Leu Gly Ile Val Cys Pr - #o Ile Cys#                 10- (2) INFORMATION FOR SEQ ID NO:4:-      (i) SEQUENCE CHARACTERISTICS:#acids    (A) LENGTH: 13 amino     (B) TYPE: amino acid     (D) TOPOLOGY: linear-     (ii) MOLECULE TYPE: peptide-     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:4:- Ala Leu Met Gly Thr Leu Gly Ile Val Cys Pr - #o Ile Cys#                 10- (2) INFORMATION FOR SEQ ID NO:5:-      (i) SEQUENCE CHARACTERISTICS:#pairs    (A) LENGTH: 117 base     (B) TYPE: nucleic acid     (C) STRANDEDNESS: single     (D) TOPOLOGY: linear-     (ii) MOLECULE TYPE: HLA-DRalpha-A2.1/4-     (ix) FEATURE:     (A) NAME/KEY: Coding Se - #quence     (B) LOCATION: 1...120-      (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #5:- ATG GCC ATA AGT GGA GTC CCT GTG CTA GGA TT - #T TTC ATC ATA GCT GTG  48Met Ala Ile Ser Gly Val Pro Val Leu Gly Ph - #e Phe Ile Ile Ala Val#                 15- CTG ATG AGC GCT CAG GAA TCA TGG GCT GCC CT - #G ATG GGC ACC CTG GGC  96Leu Met Ser Ala Gln Glu Ser Trp Ala Ala Le - #u Met Gly Thr Leu Gly#             30#                 117 TGC TGAIle Val Cys Pro Ile Cys    35- (2) INFORMATION FOR SEQ ID NO:6:-      (i) SEQUENCE CHARACTERISTICS:#acids    (A) LENGTH: 38 amino     (B) TYPE: amino acid     (D) TOPOLOGY: linear-     (ii) MOLECULE TYPE: protein-      (v) FRAGMENT TYPE: internal-     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:6:- Met Ala Ile Ser Gly Val Pro Val Leu Gly Ph - #e Phe Ile Ile Ala Val#                 15- Leu Met Ser Ala Gln Glu Ser Trp Ala Ala Le - #u Met Gly Thr Leu Gly#             30- Ile Val Cys Pro Ile Cys    35- (2) INFORMATION FOR SEQ ID NO:7:-      (i) SEQUENCE CHARACTERISTICS:#pairs    (A) LENGTH: 4665 base     (B) TYPE: nucleic acid     (C) STRANDEDNESS: single     (D) TOPOLOGY: circular-     (ii) MOLECULE TYPE: pBIOTOPEHPV-     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:7:- GCACTTTTCG GGGAAATGTG CGCGGAACCC CTATTTGTTT ATTTTTCTAA AT - #ACATTCAA  60- ATATGTATCC GCTCATGAGA CAATAACCCT GATAAATGCT TCAATAATAT TG - #AAAAAGGA 120- AGAGTCCTGA GGCGGAAAGA ACCAGCTGTG GAATGTGTGT CAGTTAGGGT GT - #GGAAAGTC 180- CCCAGGCTCC CCAGCAGGCA GAAGTATGCA AAGCATGCAT CTCAATTAGT CA - #GCAACCAG 240- GTGTGGAAAG TCCCCAGGCT CCCCAGCAGG CAGAAGTATG CAAAGCATGC AT - #CTCAATTA 300- GTCAGCAACC ATAGTCCCGC CCCTAACTCC GCCCATCCCG CCCCTAACTC CG - #CCCAGTTC 360- CGCCCATTCT CCGCCCCATG GCTGACTAAT TTTTTTTATT TATGCAGAGG CC - #GAGGCCGC 420- CTCGGCCTCT GAGCTATTCC AGAAGTAGTG AGGAGGCTTT TTTGGAGGCC TA - #GGCTTTTG 480- CAAAGATCGA TCAAGAGACA GGATGAGGAT CGTTTCGCAT GATTGAACAA GA - #TGGATTGC 540- ACGCAGGTTC TCCGGCCGCT TGGGTGGAGA GGCTATTCGG CTATGACTGG GC - #ACAACAGA 600- CAATCGGCTG CTCTGATGCC GCCGTGTTCC GGCTGTCAGC GCAGGGGCGC CC - #GGTTCTTT 660- TTGTCAAGAC CGACCTGTCC GGTGCCCTGA ATGAACTGCA AGACGAGGCA GC - #GCGGCTAT 720- CGTGGCTGGC CACGACGGGC GTTCCTTGCG CAGCTGTGCT CGACGTTGTC AC - #TGAAGCGG 780- GAAGGGACTG GCTGCTATTG GGCGAAGTGC CGGGGCAGGA TCTCCTGTCA TC - #TCACCTTG 840- CTCCTGCCGA GAAAGTATCC ATCATGGCTG ATGCAATGCG GCGGCTGCAT AC - #GCTTGATC 900- CGGCTACCTG CCCATTCGAC CACCAAGCGA AACATCGCAT CGAGCGAGCA CG - #TACTCGGA 960- TGGAAGCCGG TCTTGTCGAT CAGGATGATC TGGACGAAGA GCATCAGGGG CT - #CGCGCCAG1020- CCGAACTGTT CGCCAGGCTC AAGGCGAGCA TGCCCGACGG CGAGGATCTC GT - #CGTGACCC1080- ATGGCGATGC CTGCTTGCCG AATATCATGG TGGAAAATGG CCGCTTTTCT GG - #ATTCATCG1140- ACTGTGGCCG GCTGGGTGTG GCGGACCGCT ATCAGGACAT AGCGTTGGCT AC - #CCGTGATA1200- TTGCTGAAGA GCTTGGCGGC GAATGGGCTG ACCGCTTCCT CGTGCTTTAC GG - #TATCGCCG1260- CTCCCGATTC GCAGCGCATC GCCTTCTATC GCCTTCTTGA CGAGTTCTTC TG - #AGCGGGAC1320- TCTGGGGTTC GAAATGACCG ACCAAGCGAC GCCCAACCTG CCATCACGAG AT - #TTCGATTC1380- CACCGCCGCC TTCTATGAAA GGTTGGGCTT CGGAATCGTT TTCCGGGACG CC - #GGCTGGAT1440- GATCCTCCAG CGCGGGGATC TCATGCTGGA GTTCTTCGCC CACCCTAGGG GG - #AGGCTAAC1500- TGAAACACGG AAGGAGACAA TACCGGAAGG AACCCGCGCT ATGACGGCAA TA - #AAAAGACA1560- GAATAAAACG CACGGTGTTG GGTCGTTTGT TCATAAACGC GGGGTTCGGT CC - #CAGGGCTG1620- GCACTCTGTC GATACCCCAC CGAGACCCCA TTGGGGCCAA TACGCCCGCG TT - #TCTTCCTT1680- TTCCCCACCC CACCCCCCAA GTTCGGGTGA AGGCCCAGGG CTCGCAGCCA AC - #GTCGGGGC1740- GGCAGGCCCT GCCATAGCCT CAGGTTACTC ATATATACTT TAGATTGATT TA - #AAACTTCA1800- TTTTTAATTT AAAAGGATCT AGGTGAAGAT CCTTTTTGAT AATCTCATGA CC - #AAAATCCC1860- TTAACGTGAG TTTTCGTTCC ACTGAGCGTC AGACCCCGTA GAAAAGATCA AA - #GGATCTTC1920- TTGAGATCCT TTTTTTCTGC GCGTAATCTG CTGCTTGCAA ACAAAAAAAC CA - #CCGCTACC1980- AGCGGTGGTT TGTTTGCCGG ATCAAGAGCT ACCAACTCTT TTTCCGAAGG TA - #ACTGGCTT2040- CAGCAGAGCG CAGATACCAA ATACTGTTCT TCTAGTGTAG CCGTAGTTAG GC - #CACCACTT2100- CAAGAACTCT GTAGCACCGC CTACATACCT CGCTCTGCTA ATCCTGTTAC CA - #GTGGCTGC2160- TGCCAGTGGC GATAAGTCGT GTCTTACCGG GTTGGACTCA AGACGATAGT TA - #CCGGATAA2220- GGCGCAGCGG TCGGGCTGAA CGGGGGGTTC GTGCACACAG CCCAGCTTGG AG - #CGAACGAC2280- CTACACCGAA CTGAGATACC TACAGCGTGA GCTATGAGAA AGCGCCACGC TT - #CCCGAAGG2340- GAGAAAGGCG GACAGGTATC CGGTAAGCGG CAGGGTCGGA ACAGGAGAGC GC - #ACGAGGGA2400- GCTTCCAGGG GGAAACGCCT GGTATCTTTA TAGTCCTGTC GGGTTTCGCC AC - #CTCTGACT2460- TGAGCGTCGA TTTTTGTGAT GCTCGTCAGG GGGGCGGAGC CTATGGAAAA AC - #GCCAGCAA2520- CGCGGCCTTT TTACGGTTCC TGGCCTTTTG CTGGCCTTTT GCTCACATGT TC - #TTTCCTGC2580- GTTATCCCCT GATTCTGTGG ATAACCGTAT TACCGCCATG CATTAGTTAT TA - #ATAGTAAT2640- CAATTACGGG GTCATTAGTT CATAGCCCAT ATATGGAGTT CCGCGTTACA TA - #ACTTACGG2700- TAAATGGCCC GCCTGGCTGA CCGCCCAACG ACCCCCGCCC ATTGACGTCA AT - #AATGACGT2760- ATGTTCCCAT AGTAACGCCA ATAGGGACTT TCCATTGACG TCAATGGGTG GA - #GTATTTAC2820- GGTAAACTGC CCACTTGGCA GTACATCAAG TGTATCATAT GCCAAGTACG CC - #CCCTATTG2880- ACGTCAATGA CGGTAAATGG CCCGCCTGGC ATTATGCCCA GTACATGACC TT - #ATGGGACT2940- TTCCTACTTG GCAGTACATC TACGTATTAG TCATCGCTAT TACCATGGTG AT - #GCGGTTTT3000- GGCAGTACAT CAATGGGCGT GGATAGCGGT TTGACTCACG GGGATTTCCA AG - #TCTCCACC3060- CCATTGACGT CAATGGGAGT TTGTTTTGGC ACCAAAATCA ACGGGACTTT CC - #AAAATGTC3120- GTAACAACTC CGCCCCATTG ACGCAAATGG GCGGTAGGCG TGTACGGTGG GA - #GGTCTATA3180- TAAGCAGAGC TGGTTTAGTG AACCGTCAGA TCCGCTAGAG CTTGCTTGTT CT - #TTTTGCAG3240- AAGCTCAGAA TAAACGCTCA ACTTTGGCAG ATCCGCGGCT CGAGCCACCA TG - #GACATGGC3300- CATAAGTGGA GTCCCTGTGC TAGGATTTTT CATCATAGCT GTGCTGATGA GC - #GCTCAGGA3360- ATCATGGGCT GCCCTGATGG GCACCCTGGG CATCGTGTGC CCCATCTGCT GA - #GCTCCTGG3420- AATTCGGATC TGGTTACCAC TAAACCAGCC TCAAGAACAC CCGAATGGAG TC - #TCTAAGCT3480- ACATAATACC AACTTACACT TTACAAAATG TTGTCCCCCA AAATGTAGCC AT - #TCGTATCT3540- GCTCCTAATA AAAAGAAAGT TTCTTCACAT TCTAAAAAAA AAAAAAAAAA AA - #AAAAAAAA3600- AAAAAACCCC CCCCCCCCCC CCCCATCGAT TTTCCACCCG GGTGGGGTAC CA - #GGTAAGTG3660- TACCCAATTC GCCCTATAGT GAGTCGTATT ACAATTCACT GGCCGTCGTT TT - #ACAACGTC3720- GTGACTGGGA AAACCCTGGC GTTACCCAAA TTAATCGCCT TGCAGCACAT CC - #CCCTTTCG3780- CCAGCTGGCG TAATAGCGAA GAGGCCCGCA CCGATCGCCC TTCCCAACAG TT - #GCGCAGCC3840- TGAATGGCGA ATGGAGATCC AATTTTTAAG TGTATAATGT GTTAAACTAC TG - #ATTCTAAT3900- TGTTTGTGTA TTTTAGATTC ACAGTCCCAA GGCTCATTTC AGGCCCCTCA GT - #CCTCACAG3960- TCTGTTCATG ATCATAATCA GCCATACCAC ATTTGTAGAG GTTTTACTTG CT - #TTAAAAAA4020- CCTCCCACAC CTCCCCCTGA ACCTGAAACA TAAAATGAAT GCAATTGTTG TT - #GTTAACTT4080- GTTTATTGCA GCTTATAATG GTTACAAATA AAGCAATAGC ATCACAAATT TC - #ACAAATAA4140- AGCATTTTTT TCACTGCATT CTAGTTGTGG TTTGTCCAAA CTCATCAATG TA - #TCTTAACG4200- CGTAAATTGT AAGCGTTAAT ATTTTGTTAA AATTCGCGTT AAATTTTTGT TA - #AATCAGCT4260- CATTTTTTAA CCAATAGGCC GAAATCGGCA AAATCCCTTA TAAATCAAAA GA - #ATAGACCG4320- AGATAGGGTT GAGTGTTGTT CCAGTTTGGA ACAAGAGTCC ACTATTAAAG AA - #CGTGGACT4380- CCAACGTCAA AGGGCGAAAA ACCGTCTATC AGGGCGATGG CCCACTACGT GA - #ACCATCAC4440- CCTAATCAAG TTTTTTGGGG TCGAGGTGCC GTAAAGCACT AAATCGGAAC CC - #TAAAGGGA4500- GCCCCCGATT TAGAGCTTGA CGGGGAAAGC CGGCGAACGT GGCGAGAAAG GA - #AGGGAAGA4560- AAGCGAAAGG AGCGGGCGCT AGGGCGCTGG CAAGTGTAGC GGTCACGCTG CG - #CGTAACCA4620#                4665AT GCGCCGCTAC AGGGCGCGTC AGGTG- (2) INFORMATION FOR SEQ ID NO:8:-      (i) SEQUENCE CHARACTERISTICS:#pairs    (A) LENGTH: 27 base     (B) TYPE: nucleic acid     (C) STRANDEDNESS: single     (D) TOPOLOGY: linear-     (ii) MOLECULE TYPE: DNA-     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:8:#             27   TAAG TGGAGTC- (2) INFORMATION FOR SEQ ID NO:9:-      (i) SEQUENCE CHARACTERISTICS:#pairs    (A) LENGTH: 27 base     (B) TYPE: nucleic acid     (C) STRANDEDNESS: single     (D) TOPOLOGY: linear-     (ii) MOLECULE TYPE: DNA-     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:9:#             27   GATT CCTGAGC- (2) INFORMATION FOR SEQ ID NO:10:-      (i) SEQUENCE CHARACTERISTICS:#pairs    (A) LENGTH: 27 base     (B) TYPE: nucleic acid     (C) STRANDEDNESS: single     (D) TOPOLOGY: linear-     (ii) MOLECULE TYPE: DNA-     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:10:#             27   TCGA GGCCCAG- (2) INFORMATION FOR SEQ ID NO:11:-      (i) SEQUENCE CHARACTERISTICS:#pairs    (A) LENGTH: 27 base     (B) TYPE: nucleic acid     (C) STRANDEDNESS: single     (D) TOPOLOGY: linear-     (ii) MOLECULE TYPE: DNA-     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:11:#             27   TTGT CCACGGC- (2) INFORMATION FOR SEQ ID NO:12:-      (i) SEQUENCE CHARACTERISTICS:#pairs    (A) LENGTH: 61 base     (B) TYPE: nucleic acid     (C) STRANDEDNESS: single     (D) TOPOLOGY: linear-     (ii) MOLECULE TYPE: DNA-     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:12:- ATCAGCGCTC AGGAATCATG GGCTGCCCTG GGCATCGTGT GCCCCATCTG CT - #GAGCTCGA  60#               61- (2) INFORMATION FOR SEQ ID NO:13:-      (i) SEQUENCE CHARACTERISTICS:#pairs    (A) LENGTH: 24 base     (B) TYPE: nucleic acid     (C) STRANDEDNESS: single     (D) TOPOLOGY: linear-     (ii) MOLECULE TYPE: DNA-     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:13:#                24CGAG CTCA- (2) INFORMATION FOR SEQ ID NO:14:-      (i) SEQUENCE CHARACTERISTICS:#pairs    (A) LENGTH: 70 base     (B) TYPE: nucleic acid     (C) STRANDEDNESS: single     (D) TOPOLOGY: linear-     (ii) MOLECULE TYPE: DNA-     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:14:- ATCAGCGCTC AGGAATCATG GGCTCTGATG GGCACCCTGG GCATCGTGTG CC - #CCATCTGC  60#        70- (2) INFORMATION FOR SEQ ID NO:15:-      (i) SEQUENCE CHARACTERISTICS:#pairs    (A) LENGTH: 24 base     (B) TYPE: nucleic acid     (C) STRANDEDNESS: single     (D) TOPOLOGY: linear-     (ii) MOLECULE TYPE: DNA-     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:15:#                24CGAG CTCA- (2) INFORMATION FOR SEQ ID NO:16:-      (i) SEQUENCE CHARACTERISTICS:#acids    (A) LENGTH: 12 amino     (B) TYPE: amino acid     (D) TOPOLOGY: linear-     (ii) MOLECULE TYPE: peptide-     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:16:- Leu Met Gly Thr Leu Gly Ile Val Cys Pro Il - #e Cys#                 10- (2) INFORMATION FOR SEQ ID NO:17:-      (i) SEQUENCE CHARACTERISTICS:#acids    (A) LENGTH: 9 amino     (B) TYPE: amino acid     (D) TOPOLOGY: linear-     (ii) MOLECULE TYPE: peptide-     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:17:- Tyr Met Leu Asp Leu Gln Pro Glu Thr  1               5- (2) INFORMATION FOR SEQ ID NO:18:-      (i) SEQUENCE CHARACTERISTICS:#acids    (A) LENGTH: 25 amino     (B) TYPE: amino acid     (D) TOPOLOGY: linear-     (ii) MOLECULE TYPE: peptide-     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:18:- Met Ala Ile Ser Gly Val Pro Val Leu Gly Ph - #e Phe Ile Ile Ala Val#                 15- Leu Met Ser Ala Gln Glu Ser Trp Ala#             25- (2) INFORMATION FOR SEQ ID NO:19:-      (i) SEQUENCE CHARACTERISTICS:#acids    (A) LENGTH: 13 amino     (B) TYPE: amino acid     (D) TOPOLOGY: linear-     (ii) MOLECULE TYPE: peptide-     (ix) FEATURE:     (A) NAME/KEY: Coding Se - #quence     (B) LOCATION: 1...1#where X at position 1 is Ala, Ser, Arg,          Lys, Gly, - # Gln, Asp, or Glu-     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:19:- Xaa Leu Met Gly Thr Leu Gly Ile Val Cys Pr - #o Ile Cys#                 10__________________________________________________________________________