This paper gives an overview on the research done in the fields of tax competition, coordination and harmonisation. The survey is divided in two main parts, in the first section we compare the standard tax competition literature that sees tax competition as a bad, to public choice contributions that advocate tax reductions. In the second part we consider theories of endogenous growth, which focus on analysing the taxation question. After introducing the fundamental contributions, we discuss extensions in the line of an open economy, an OLG setting and the transitional dynamics in greater detail. (author's abstract) / Series: Discussion Papers SFB International Tax Coordination

The human papillomavirus (HPV) has been a “companion” of humanity for as long as humanity has existed. The migration of peoples around the globe has given rise to more than 170 different types of the virus, which cause a variety of conditions. All five genera of HPV infect epithelial cells in the body, but only the Alphapapillomaviruses infect the genital mucosa. Most infections are benign and typically regress to subclinical within two years, but persistent infections can cause precancerous lesions. HPV types 16 and 18 are among the highest risk and account for the majority of cervical cancer, and more than 90% of all other HPV-related cancers. While the two vaccines, Gardasil and Cervarix, have been successfully implemented in the US market and some European and Asian countries, complete world penetrance has been burdened by multiple factors, including financial constraints and social norms. Treatments for established papillomas are invasive (cryosurgery, conization, etc.) and advanced malignant HPV-related tumors have been targeted with chemo- and radiotherapy with varied success. The high morbidity and long-term effects of current treatment options make clear the need for easy-to-administer, low-cost therapies, which can specifically treat both early and advanced HPV-associated cancers.<div><br></div><div>The hallmark of HPV tumors is the inactivation of p53, an evasion strategy key to the progression of HPV- derived cancers. Through an interaction between the viral protein E6 and the E3 ubiquitin ligase E6AP, p53 is polyubiquitinated and targeted for proteasomal degradation, allowing infected cells to bypass their own defense mechanisms. This work explores interruption of the association between E6 and E6AP as an opportunity to combat the infection and resulting malignancies.<br></div><div><br></div><div>In the first part of this project, disruption of the E6-E6AP interactions is pursued through the development of helical stabilized peptidomimetics of the LxxLL motif, which E6AP uses for E6 recognition and binding. Several reports have indicated that targeting the E6 binding groove is a viable means for disrupting the interaction. However, reported peptides were not cell permeable or optimized for α-helicity and proteolytic resistance (for reference, the LxxLL motif is an α-helix when bound). To address this challenge a peptide stabilization strategy was applied, which uses an all-hydrocarbon chain to connect two non-adjacent residues and enforce α-helicity. Results from in silico simulations and biochemical assay with these new stapled peptides showed that affinity for E6, α-helicity, and cell permeability can all be improved with the installment of the proper staple.<br></div><div><br></div><div>The second question examined by this work is whether fragment-based drug design can be successfully employed to derive new small-molecule inhibitors of the formation of the E6-E6AP complex. From a design perspective, the significant challenge was to define discreet binding hot-spots capable of accommodating fragments with reasonable affinity, which can then be linked together into a complete ligand. Using existing structural knowledge of the E6 protein and computational hot-spot searching tools, three previously-unidentified regions (sub-pockets) on E6 were discovered, which are near but not directly engaged by either the E6AP motif or p53. Using high-throughput in silico and biochemical screening, three sets of sub-pocket specific fragments were defined and elaborated into larger molecules with two different scaffolds. As a result, the work herein presents a stepwise approach to targeting the E6-E6AP protein-protein interaction – the discovery of new binding hot spots, the identification of site-specific fragments, and the design of complete molecules with versatile scaffold.<br></div>

No description available.

This paper responds to the development policy debate involving the World Bank and the IMF on the use of fiscal policy not only for economic stabilization but also to promote economic growth and increase per capita income. A key issue in this debate relates to the effect of the composition of public expenditure on economic growth. Policy makers and some researchers have argued that expenditure on growth-enhancing functions could enhance future revenue and justify the provision of "fiscal space" in the budget. But there are no simple ways to identify the growth-maximizing composition of public expenditure. The current paper lays out a research strategy to explore the effects of fiscal policy, including the composition of public expenditure, on economic growth, using a time series approach. Based on the modeling strategy of Greiner, Semmler and Gong (2005) we develop a general model that features a government that undertakes public expenditure on (a) education and health facilities which enhance human capital, (b) public infrastructure such as roads and bridges necessary for market activity, (c) public administration to support government functions, (d) transfers and public consumption facilities, and (e) debt service. The proposed model is numerically solved, calibrated and the impact of the composition of public expenditure on the long-run per capita income explored for low-, lower-middle- and uppermiddle-income countries. Policy implications and practical policy rules are spelled out, the extension to an estimable model indicated, a debt sustainability test proposed, and the out-of-steady-state dynamics studied.

Le cancer du col utérin (CCU) est dans plus de 99% des cas provoqué par une infection avec le virus du papillome humain (VPH), dont le potentiel oncogénique réside dans l'expression des proto-oncogènes viraux E6/E7. Le potentiel carcinogénique de ces protéines virales réside essentiellement dans leurs actions sur les produits des gènes suppresseurs de tumeur p53 et RB. Les produits de ces gènes, p53 et Rb, font parti des voies de signalisation de réponse aux dommages de l'ADN cellulaire (RDA) et leur perte entraine une perte de fonctionnalité qui mène à une instabilité génomique. À long terme et en présence de d'autres facteurs ceux-ci mèneront au développement d'un cancer. Les protéines E6 et E7 sont constitutivement exprimées dans les cellules du CCU ainsi que dans les cellules de tout autre cancer induit par le VPH et seulement dans ces dernières. La prise en charge des cas avancés de ces cancers se fait principalement par radiothérapie et chimiothérapie concomitante. La chimio-radiothérapie utilisée en traitement est efficace mais résulte en un taux élevé de morbidité et un nombre important de patientes récidiveront. Nous proposons que l'exploitation de l'expression spécifique d’E6 et d’E7 dans les cellules du CCU permette d’envisager une stratégie de létalité synthétique afin d'amplifier l'effet létal de l'irradiation sur les cellules CCU. Ceci permettrait potentiellement d'augmenter l'efficacité du traitement et de diminuer les récidives, ainsi que la morbidité liée au traitement. En s'appuyant sur cette hypothèse, notre objectif est d’identifier des composés dont l'action seule ou couplée à l'irradiation provoquerait préférentiellement la mort des cellules exprimant les protéines E6 et E7 du VPH. Les cellules testées comprennent des cellules isogéniques humaines issues de kératinocytes normaux que nous avons modifiées séquentiellement pour obtenir les modifications associées aux cellules CCU (hTERT, E6 et E7), ainsi que les lignées de cellules de CCU HeLa et CaSki .Nous avons procédé à la mise au point et à la validation du protocole de criblage et des méthodes d’évaluation de la sensibilisation, qui se définit comme une perte de viabilité, un arrêt ou ralentissement de la croissance, par détection d’ATP ainsi que par coloration d’ADN génomique au DRAQ5. Suite à un criblage ciblé impliquant des inhibiteurs connus de la voie de réparation des dommages à l’ADN, nous avons identifié l’inhibiteur de mdm2, Nutlin-3, comme étant un composé sensibilisant et radio-sensibilisant préférentiellement les cellules exprimant E6 et E7 du VPH. La Nutlin-3 a été testée sur des cellules HEKn-hTERT-E6-E7, des cellules CaSki et HeLa. L’effet de sensibilisation et de radio-sensibilisation a été confirmé dans ces trois lignées. Tel que suggéré par son action sur mdmd2, la Nutlin-3 permet la stabilisation de p53 dans les cellules HEKn-hTERT-E6-E7 et CaSki et sa réactivation dans les lignées cellulaires HeLa et CaSki. Malgré cette stabilisation de p53, de façon surprenante, l’effet de la Nutlin-3 sur la sensibilisation et la radio-sensibilisation des cellules HeLa et CaSki semble indépendant de p53, tel qu’observé en utilisant des cellules HeLa-GSE et CaSki-GSE dont le p53 est déficient. In vivo la Nutlin-3a montre dans un essai préliminaire l’inhibition de la croissance tumorale des xénogreffes HeLa chez des souris RAG2γc. Ce résultat reste à confirmer avec un essai impliquant un nombre d’échantillons plus grand. À plus long terme, nous comptons étudier l’implication de mdm2 dans l’effet de sensibilisant de la Nutlin-3 dans les cellules CCUs, ainsi que les autres cibles pouvant être impliquées dans la création de cet effet sensibilisant observé. / More than 99% of uterine cervical cancer (UCC) are caused by human papillomavirus (HPV) infections. The oncogenic potential of this virus lies in the expression of the proto-oncogenes E6/E7. These viral proteins are considered carcinogenic because of their effects on tumor suppressor proteins p53 and Rb. E6 and E7 promote p53 and Rb inactivation resulting in a loss of function in the DNA damage response pathways (DDR), genomic instability, and cancer development. The E6 and E7 proteins are expressed constitutively and specifically in cervical cancer cells and in the cells of other HPV-induced cancers. The treatment of advanced UCC is based on simultaneous radiotherapy and chemotherapy. Although these strategies are somewhat efficacious, there are still significant co-morbidities and cancer relapses. We hypothesized that the specific expression of E6 and E7 in cervical cancer cells can be exploited in a synthetic lethality strategy to amplify the lethal effect of irradiation. Thus, the efficacy of treatment could be increased, while reducing the cancer recurrence and treatment-related morbidities. Our objective is to identify chemical compounds that if used alone or coupled with irradiation, would preferentially induce the death of cells expressing proteins E6 and E7 of HPV. We used a cellular model of human keratinocytes that were modified to obtain the genetic signature associated with cervical cancer cells (the expression of E6 and E7). We then proceeded to the optimization and validation of the methods used to evaluate the sensitization of the tested cells. To measure sensitization, we evaluated the quantity of cellular ATP by ATPlite assay and the cellular DNA content with the DNA stain DRAQ5. After establishing a screening protocol, we proceeded to a low-density screening to identify a compound that can sensitize or radio-sensitize cervical cancer cells expressing the HPV proteins E6 and E7. We identified Nutlin-3 a mdm2, inhibitor, as a radio-sensitizing component for cells expressing E6 and E7 of HPV. Nutlin-3 was tested and sensitization confirmed in HEKn-hTERT-E6-E7 and in the cervical cancer cell lines HeLa and CaSki. We confirmed by Western-Blot the stabilisation of p53 in HEKn-hTERT-E6-E7 and CaSki cells treated with Nutlin-3. Moreover, Nutlin-3 promotes p53 reactivation in the HeLa and CaSki cell lines. Surprisingly, the effect of Nutlin-3 on the sensitization and radio-sensitization of the HeLa and CaSki cell lines appears to be p53-independent. This is based on the observations made using p53-deficient HeLa-GSE and CaSki-GSE cell lines, which were also sensitized by Nutlin-3. In addition, preliminary experiments showed that Nutlin-3a inhibits in vivo tumor growth, as seen using xenografts of HeLa in mice with a RAG2γc genetic background. This remains to be confirmed using an extended cohort of mice. In the future, it will be important to examine the implication of mdm2 in the sensitization effect of Nutlin-3 in cervical cancer cells and to find others possible targets that may play a role in the sensitization effect of Nutlin-3 observed in cervical cancer cells.

O câncer cervical é o segundo câncer mais comum entre mulheres no mundo. A maioria dos casos (83%) ocorre em países em desenvolvimento, onde são encontrados em estágios relativamente avançados e, conseqüentemente, a sobrevida média é de cerca de 49% após cinco anos. Portanto, uma vacina eficaz contra as infecções pelo HPV pode levar ao controle do câncer do colo do útero. Apesar de prevenir, a vacina profilática não é acessível em função do alto custo, além de não eliminar o vírus em mulheres já infectadas pelo HPV. Assim, propusemos o desenvolvimento de uma vacina terapêutica eficaz utilizando duas abordagens: VLPs (virus-like particles) quiméricas, que poderiam apresentar propriedades profiláticas e terapêuticas, obtidas da fusão das proteína L1 e E7; proteínas quiméricas obtidas a partir da fusão de epítopos das proteínas E6 e E7 do HPV16, com e sem ubiquitina. Após subclonagens, com a obtenção dos vetores pPICHOLI-L1&#916;CE71-50 e pPICHOLI-L1&#916;CE743-77, partiu-se para a indução da expressão das VLPs quiméricas em Pichia pastoris, das quais não foram detectadas expressão protéica. Realizaram-se inúmeras modificações no protocolo de indução. Mesmo após essas alterações não foi detectada nenhuma expressão das fusões L1&#916;CE71-50 ou L1&#916;CE743-77. Como alternativa de uma vacina terapêutica, nos propusemos a expressar em E. coli proteínas sintéticas originadas da fusão entre epítopos das proteínas E6 e E7 do HPV16, com ou sem Ubiquitina, visando aumentar a apresentação de peptídeos via MHC de classe I de modo a estimular a eliminação de células infectadas com HPV16, evitando e regredindo o desenvolvimento dessas células cancerosas. Com a proteína E6E7 solúvel e purificada, realizou-se um ensaio de imunização. Nesse experimento, 20% dos animais imunizados com a proteína E6E7 não apresentaram desenvolvimento de tumor após a inoculação de células TC1. Assim isso nos leva a crer que com o aumento da concentração de proteína e utilização de adjuvantes seria possível aumentar o número de animais resistentes ao desenvolvimento do tumor. Em um segundo experimento de imunização, comparamos as proteínas E6E7 e E6E7Ub, em duas concentrações, 15 e 40 &#181;g, e também com ou sem o adjuvante whole cell pertussis (WCP). Independentemente da concentração e presença ou ausência de WCP, os grupos imunizados com E6E7Ub apresentaram proteção contra o tumor entre 80% e 100% dos camundongos, enquanto os grupos imunizados com E6E7 apresentaram proteção entre 0% e 25%. Esses resultados são promissores, ainda que preliminares, indicando um potencial de uso da proteína E6E7Ub como imunógeno para vacina terapêutica contra o câncer cervical induzido por HPV16 / Cervical cancer is the second most common cancer among women worldwide. Most cases (83%) occur in developing countries, where they are found in relatively advanced stages and, consequently, the median survival is about 49% after five years. Therefore, an effective vaccine against HPV infections can lead to control of cancer of the cervix. Although preventable, the prophylactic HPV vaccine is not accessible to all due to their high cost and in addition the vaccine does not eliminate the HPV in infected women. We have therefore proposed the development of effective therapeutic vaccines using two approaches: chimeric VLPs (virus-like particles), endowed with prophylactic and therapeutic properties, obtained from the fusion protein L1 and E7; chimeric proteins derived from the fusion of epitopes of proteins E6 and E7 of HPV16 with and without ubiquitin. After subcloning, we obtained the vectors pPICHOLI-L1&#916;CE71-50 and L1 pPICHOLI- L1&#916;CE743-77. After transformation of yeast Pichia pastoris with these constructions, the cells were induced, but it was not possible to detect any recombinant protein expression. As an alternative, we proposed the expression of synthetic proteins in E. coli derived from the fusion between epitopes of E6 and E7 proteins of HPV16 with or without Ubiquitin, in order to enhance the presentation of peptides through MHC class I to stimulate the elimination of HPV16-infected cells, preventing and regressing the development of cancer cells. Soluble E6E7 protein was purified and, 20% of the animals immunized with this protein did not develop tumor after inoculation of TC1 cells. In a second immunization experiment we compared the proteins E6E7 and E6E7Ub, in two concentrations, 15 and 40&#181;g, with or without the adjuvant whole cell pertussis (WCP). Regardless of concentration and presence or absence of WCP, all the groups immunized with E6E7Ub showed protection against tumor between 80% and 100%, while the groups immunized with E6E7 showed protection from 0% to 25%. These results are promising and although preliminary, indicate the potential of E6E7Ub protein as an immunogen, for a therapeutic vaccine against cervical cancer induced by HPV16

<p>Oncogenic human papillomaviruses (HPVs) are implicated in 99.7 % of cervical cancer cases but require the co-operation of other factors. To investigate potential genetic risk factors we have typed the HLA class II DRB1 and DQB1 loci in 478 women diagnosed with cervical carcinoma in situ and in 608 age-matched controls. Quantitative measurements of HPV 16, HPV 18/45 and HPV 31 were obtained. The DRB1*1501 and DQB1*0602 alleles were found to increase the risk of HPV 16 infection. Carriers of DRB1*1501 and DQB1*0602 were also shown to have an increased risk of a higher viral load compared to non-carriers. The DRB1*1301 and DQB1*0603 alleles were found to protect from HPV 18/45 and 31 infections as well as resulting in a lower viral load in carriers compared to non-carriers. Women with a high HPV 16, 18/45 or 31 viral load were more prone to long-term infections and women with a low HPV 16 viral load were more prone to short-term infections. Carriers of DRB1*1501 and DQB1*0602 alleles were also shown to have an increased risk of long-term infections compared to short-term infections. We also tested if an HPV susceptibility locus found for epidermodysplasia verruciformis (EV) was also linked to HPV susceptibility in cervical cancer. We did not find any linkage to this locus in a set of 77 families, each with at least three cases diagnosed with cervical carcinoma in situ. Other potential risk factors tested were HPV 16 E6 variants together with a p53 codon 72 polymorphism and HLA class II alleles. We found an association between the E6 L83V variant and the HLA DR4-DQ3 haplotype, as well as an increased frequency of Arg homozygosity of p53 in women infected with the L83V variant. These results show that alleles at HLA class II loci represents risk factors for persistent HPV infection and thereby also contribute to the risk of development of cervical carcinoma <i>in situ</i>.</p>

Oncogenic human papillomaviruses (HPVs) are implicated in 99.7 % of cervical cancer cases but require the co-operation of other factors. To investigate potential genetic risk factors we have typed the HLA class II DRB1 and DQB1 loci in 478 women diagnosed with cervical carcinoma in situ and in 608 age-matched controls. Quantitative measurements of HPV 16, HPV 18/45 and HPV 31 were obtained. The DRB1*1501 and DQB1*0602 alleles were found to increase the risk of HPV 16 infection. Carriers of DRB1*1501 and DQB1*0602 were also shown to have an increased risk of a higher viral load compared to non-carriers. The DRB1*1301 and DQB1*0603 alleles were found to protect from HPV 18/45 and 31 infections as well as resulting in a lower viral load in carriers compared to non-carriers. Women with a high HPV 16, 18/45 or 31 viral load were more prone to long-term infections and women with a low HPV 16 viral load were more prone to short-term infections. Carriers of DRB1*1501 and DQB1*0602 alleles were also shown to have an increased risk of long-term infections compared to short-term infections. We also tested if an HPV susceptibility locus found for epidermodysplasia verruciformis (EV) was also linked to HPV susceptibility in cervical cancer. We did not find any linkage to this locus in a set of 77 families, each with at least three cases diagnosed with cervical carcinoma in situ. Other potential risk factors tested were HPV 16 E6 variants together with a p53 codon 72 polymorphism and HLA class II alleles. We found an association between the E6 L83V variant and the HLA DR4-DQ3 haplotype, as well as an increased frequency of Arg homozygosity of p53 in women infected with the L83V variant. These results show that alleles at HLA class II loci represents risk factors for persistent HPV infection and thereby also contribute to the risk of development of cervical carcinoma in situ.

L' oncoprotéine E6 - qui joue un rôle crucial dans le processus d'oncogenèse induit par les papillomavirus a longtemps résisté à toute analyse. Depuis 1995 l'équipe Oncoprotéines a concentré ses efforts sur cette problématique. Ce qui a permis la résolution par RMN de la structure du domaine C-terminal de E6 en 2006. C'est dans ce cadre que j'ai commencé ce Doctorat en 2008, avec objectif de continuer la quête de données structurales sur E6 tout en acquérant des informations sur ses modes d'interaction avec ses cibles cellulaires. Les travaux de cette thèse ont permis l'obtention de la structure cristallographique de E6 (HPV16) en complexe avec un peptide de E6AP, en utilisant une approche originale capable de produire des protéines E6 stables et solubles. Cette structure constitue la première information structurale publiée sur des protéines E6 entières, attendue depuis plus de 20 ans par la communauté scientifique. J'ai effectué également durant cette thèse une analyse du système d'interaction de la protéine E6 basée sur une large étude d'interaction entre les protéines E6 (7 types) et 93 peptides porteurs de motif LxxLL.

O câncer cervical é o segundo câncer mais comum entre mulheres no mundo. A maioria dos casos (83%) ocorre em países em desenvolvimento, onde são encontrados em estágios relativamente avançados e, conseqüentemente, a sobrevida média é de cerca de 49% após cinco anos. Portanto, uma vacina eficaz contra as infecções pelo HPV pode levar ao controle do câncer do colo do útero. Apesar de prevenir, a vacina profilática não é acessível em função do alto custo, além de não eliminar o vírus em mulheres já infectadas pelo HPV. Assim, propusemos o desenvolvimento de uma vacina terapêutica eficaz utilizando duas abordagens: VLPs (virus-like particles) quiméricas, que poderiam apresentar propriedades profiláticas e terapêuticas, obtidas da fusão das proteína L1 e E7; proteínas quiméricas obtidas a partir da fusão de epítopos das proteínas E6 e E7 do HPV16, com e sem ubiquitina. Após subclonagens, com a obtenção dos vetores pPICHOLI-L1&#916;CE71-50 e pPICHOLI-L1&#916;CE743-77, partiu-se para a indução da expressão das VLPs quiméricas em Pichia pastoris, das quais não foram detectadas expressão protéica. Realizaram-se inúmeras modificações no protocolo de indução. Mesmo após essas alterações não foi detectada nenhuma expressão das fusões L1&#916;CE71-50 ou L1&#916;CE743-77. Como alternativa de uma vacina terapêutica, nos propusemos a expressar em E. coli proteínas sintéticas originadas da fusão entre epítopos das proteínas E6 e E7 do HPV16, com ou sem Ubiquitina, visando aumentar a apresentação de peptídeos via MHC de classe I de modo a estimular a eliminação de células infectadas com HPV16, evitando e regredindo o desenvolvimento dessas células cancerosas. Com a proteína E6E7 solúvel e purificada, realizou-se um ensaio de imunização. Nesse experimento, 20% dos animais imunizados com a proteína E6E7 não apresentaram desenvolvimento de tumor após a inoculação de células TC1. Assim isso nos leva a crer que com o aumento da concentração de proteína e utilização de adjuvantes seria possível aumentar o número de animais resistentes ao desenvolvimento do tumor. Em um segundo experimento de imunização, comparamos as proteínas E6E7 e E6E7Ub, em duas concentrações, 15 e 40 &#181;g, e também com ou sem o adjuvante whole cell pertussis (WCP). Independentemente da concentração e presença ou ausência de WCP, os grupos imunizados com E6E7Ub apresentaram proteção contra o tumor entre 80% e 100% dos camundongos, enquanto os grupos imunizados com E6E7 apresentaram proteção entre 0% e 25%. Esses resultados são promissores, ainda que preliminares, indicando um potencial de uso da proteína E6E7Ub como imunógeno para vacina terapêutica contra o câncer cervical induzido por HPV16 / Cervical cancer is the second most common cancer among women worldwide. Most cases (83%) occur in developing countries, where they are found in relatively advanced stages and, consequently, the median survival is about 49% after five years. Therefore, an effective vaccine against HPV infections can lead to control of cancer of the cervix. Although preventable, the prophylactic HPV vaccine is not accessible to all due to their high cost and in addition the vaccine does not eliminate the HPV in infected women. We have therefore proposed the development of effective therapeutic vaccines using two approaches: chimeric VLPs (virus-like particles), endowed with prophylactic and therapeutic properties, obtained from the fusion protein L1 and E7; chimeric proteins derived from the fusion of epitopes of proteins E6 and E7 of HPV16 with and without ubiquitin. After subcloning, we obtained the vectors pPICHOLI-L1&#916;CE71-50 and L1 pPICHOLI- L1&#916;CE743-77. After transformation of yeast Pichia pastoris with these constructions, the cells were induced, but it was not possible to detect any recombinant protein expression. As an alternative, we proposed the expression of synthetic proteins in E. coli derived from the fusion between epitopes of E6 and E7 proteins of HPV16 with or without Ubiquitin, in order to enhance the presentation of peptides through MHC class I to stimulate the elimination of HPV16-infected cells, preventing and regressing the development of cancer cells. Soluble E6E7 protein was purified and, 20% of the animals immunized with this protein did not develop tumor after inoculation of TC1 cells. In a second immunization experiment we compared the proteins E6E7 and E6E7Ub, in two concentrations, 15 and 40&#181;g, with or without the adjuvant whole cell pertussis (WCP). Regardless of concentration and presence or absence of WCP, all the groups immunized with E6E7Ub showed protection against tumor between 80% and 100%, while the groups immunized with E6E7 showed protection from 0% to 25%. These results are promising and although preliminary, indicate the potential of E6E7Ub protein as an immunogen, for a therapeutic vaccine against cervical cancer induced by HPV16