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The family of human papillomaviruses (HPV) includes over 400 genotypes. Genus α genotypes generally infect the anogenital mucosa, and a subset of these HPV are a necessary, but not sufficient, cause of cervical cancer. Of the 13 high-risk (HR) and 11 intermediate-risk (IR) HPV associated with cervical cancer, genotypes 16 and 18 cause 50% and 20% of cases, respectively, whereas HPV16 dominates in other anogenital and oropharyngeal cancers. A plethora of βHPVs are associated with cutaneous squamous cell carcinoma (CSCC), especially in sun-exposed skin sites of epidermodysplasia verruciformis (EV), AIDS, and immunosuppressed patients. Licensed L1 virus-like particle (VLP) vaccines, such as Gardasil 9, target a subset of αHPV but no βHPV. To comprehensively target both α- and βHPVs, we developed a two-component VLP vaccine, RG2-VLP, in which L2 protective epitopes derived from a conserved αHPV epitope (amino acids 17 to 36 of HPV16 L2) and a consensus βHPV sequence in the same region are displayed within the DE loop of HPV16 and HPV18 L1 VLP, respectively. Unlike vaccination with Gardasil 9, vaccination of wild-type and EV model mice (Tmc6(Δ/Δ) or Tmc8(Δ/Δ)) with RG2-VLP induced robust L2-specific antibody titers and protected against β-type HPV5. RG2-VLP protected rabbits against 17 αHPV, including those not covered by Gardasil 9. HPV16- and HPV18-specific neutralizing antibody responses were similar between RG2-VLP- and Gardasil 9-vaccinated animals. However, only transfer of RG2-VLP antiserum effectively protected naive mice from challenge with all βHPVs tested. Taken together, these observations suggest RG2-VLP’s potential as a broad-spectrum vaccine to prevent αHPV-driven anogenital, oropharyngeal, and βHPV-associated cutaneous cancers. IMPORTANCE Licensed preventive HPV vaccines are composed of VLPs derived by expression of major capsid protein L1. They confer protection generally restricted to infection by the αHPVs targeted by the up-to-9-valent vaccine, and their associated anogenital cancers and genital warts, but do not target βHPV that are associated with CSCC in EV and immunocompromised patients. We describe the development of a two-antigen vaccine protective in animal models against known oncogenic αHPVs as well as diverse βHPVs by incorporation into HPV16 and HPV18 L1 VLP of 20-amino-acid conserved protective epitopes derived from minor capsid protein L2.

Human papillomavirus (HPV)-associated head and neck squamous cell carcinoma (HNSCC) is a growing global health problem. HPV16 has been attributed to a majority of HPV-associated HNSCCs. In order to test candidate immunotherapies, we developed a spontaneous HPV16-driven HNSCC model in HLA-A2 (AAD) transgenic mice. We sought to eliminate the confounding effects of dominant HPV antigen presentation through murine major histocompatibility complex class I (MHC-I) via epitope mutagenesis (without compromising tumorigenicity). We generated HPV16 E6(R55K)(delK75) and E7(N53S) expression constructs with mutations in known dominant H-2Db epitopes and characterized their presentation through murine and human MHC-I molecules using in vitro and in vivo activation of HPV16 E6/E7 antigen-specific CD8+ T cells. In addition, we tested the ability of E6(R55K)(delK75) and E7(N53S) for oncogenicity. The mutated E7(N53S) abolished the presentation of murine H-2Db-restricted HPV16 E7 peptide (i.e., amino acids [aa] 49 to 57) cytotoxic T lymphocyte (CTL) epitope and resulted in HLA-A2-restricted presentation of the HPV16 E7 (aa 11 to 20)-specific CTL epitope. The mutated E6(R55K)(delK75) abolished the activation of murine MHC-I-restricted E6-specific CD8+ T cell-mediated immune responses in C57BL/6 mice. In addition, the vaccination led to the activation of human HLA-A2-restricted E6-specific CD8+ T cell-mediated immune responses in HLA-A2 (AAD) transgenic mice. Injection of DNA plasmids encoding LucE7(N53S)E6(R55K)(delK75), AKT, c-Myc, and SB100 followed by electroporation results in development of squamous cell carcinoma in the oral/pharyngeal cavity of all of the HLA-A2 (AAD) transgenic mice (5/5), with 2/5 tumor-bearing mice developing metastatic carcinoma in the neck lymph nodes.

As severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spreads, variants with enhanced virulence and transmissibility have emerged. Although in vitro systems allow rapid characterization, they do not fully recapitulate the dynamic interaction of virions and neutralizing antibodies in the airway. Here, we demonstrate that the N501Y variant permits respiratory infection in unmodified mice. We utilize N501Y to survey in vivo pseudovirus infection dynamics and susceptibility to reinfection with the L452R (Los Angeles), K417N + E484K (South Africa), and L452R + K417N + E484Q (India) variants. Human coronavirus disease 2019 (COVID-19)+ or vaccinated antibody isotypes, titers, variant receptor binding domain (RBD) binding, and neutralization potential are studied, revealing numerous significant correlations. Immune escape of the K417N + E484K variant is observed because infection can be appreciated in the nasopharynx, but not lungs, of mice transferred with low-antibody-tier plasma. Conversely, near-complete protection is observed in animals receiving high-antibody-tier plasma, a phenomenon that can only be appreciated in vivo., Graphical abstract, Lam et al. develop a model of SARS-CoV-2 infection in laboratory mice. This allows researchers to study the threat of emerging variants in a more physiological context than by using cell culture systems. Interactions between SARS-CoV-2 variants and immunity are explored in the airway of mice.

The Division of Cancer Prevention of the National Cancer Institute (NCI) and the Office of Disease Prevention of the National Institutes of Health co-sponsored the Translational Advances in Cancer Prevention Agent Development Meeting on August 27 to 28, 2020. The goals of this meeting were to foster the exchange of ideas and stimulate new collaborative interactions among leading cancer prevention researchers from basic and clinical research; highlight new and emerging trends in immunoprevention and chemoprevention as well as new information from clinical trials; and provide information to the extramural research community on the significant resources available from the NCI to promote prevention agent development and rapid translation to clinical trials. The meeting included two plenary talks and five sessions covering the range from pre-clinical studies with chemo/immunopreventive agents to ongoing cancer prevention clinical trials. In addition, two NCI informational sessions describing contract resources for the preclinical agent development and cooperative grants for the Cancer Prevention Clinical Trials Network were also presented.

We demonstrate that female C57BL/6J mice are susceptible to a transient lower genital tract infection with MmuPV1 mouse papillomavirus and display focal histopathological abnormalities resembling those of human papillomavirus (HPV) infection. We took advantage of strains of genetically deficient mice to study in vivo the role of innate immune signaling in the control of papillomavirus. At 4 months, we sacrificed MmuPV1-infected mice and measured viral 757/3139 spliced transcripts by TaqMan reverse transcription-PCR (RT-PCR), localization of infection by RNAscope in situ hybridization, and histopathological abnormities by hematoxylin and eosin (H&E) staining. Among mice deficient in receptors for pathogen-associated molecular patterns, MyD88(−/−) and STING(−/−) mice had 1,350 and 80 copies of spliced transcripts/μg RNA, respectively, while no viral expression was detected in MAVS(−/−) and Ripk2(−/−) mice. Mice deficient in an adaptor molecule, STAT1(−/−), for interferon signaling had 46,000 copies/μg RNA. Among mice with targeted deficiencies in the inflammatory response, interleukin-1 receptor knockout (IL-1R(−/−)) and caspase-1(−/−) mice had 350 and 30 copies/μg RNA, respectively. Among mice deficient in chemokine receptors, CCR6(−/−) mice had 120 copies/μg RNA, while CXCR2(−/−) and CXCR3(−/−) mice were negative. RNAscope confirmed focal infection in MyD88(−/−), STAT1(−/−), and CCR6(−/−) mice but was negative for other gene-deficient mice. Histological abnormalities were seen only in the latter mice. Our findings and the literature support a working model of innate immunity to papillomaviruses involving the activation of a MyD88-dependent pathway and IL-1 receptor signaling, control of viral replication by interferon-stimulated genes, and clearance of virus-transformed dysplastic cells by the action of the CCR6/CCL20 axis. IMPORTANCE Papillomaviruses infect stratified squamous epithelia, and the viral life cycle is linked to epithelial differentiation. Additionally, changes occur in viral and host gene expression, and immune cells are activated to modulate the infectious process. In vitro studies with keratinocytes cannot fully model the complex viral and host responses and do not reflect the contribution of local and migrating immune cells. We show that female C57BL/6J mice are susceptible to a transient papillomavirus cervicovaginal infection, and mice deficient in select genes involved in innate immune responses are susceptible to persistent infection with variable manifestations of histopathological abnormalities. The results of our studies support a working model of innate immunity to papillomaviruses, and the model provides a framework for more in-depth studies. A better understanding of mechanisms of early viral clearance and the development of approaches to induce clearance will be important for cancer prevention and the treatment of HPV-related diseases.

Background Epithelial ovarian carcinomas encompass a heterogeneous group of diseases with a poor 5-year survival rate. Serous carcinoma is the most common type. Most FDA-approved serum tumor markers are glycoproteins. These glycoproteins on cell surface or shed into the bloodstream could serve as therapeutic targets as well as surrogates of tumor. In addition to glycoprotein expressions, the analysis of protein glycosylation occupancy could be important for the understanding of cancer biology as well as the identification of potential glycoprotein changes in cancer. In this study, we used an integrated proteomics and glycoproteomics approach to analyze global glycoprotein abundance and glycosylation occupancy for proteins from high-grade ovarian serous carcinoma (HGSC) and serous cystadenoma, a benign epithelial ovarian tumor, by using LC–MS/MS-based technique. Methods Fresh-frozen ovarian HGSC tissues and benign serous cystadenoma cases were quantitatively analyzed using isobaric tags for relative and absolute quantitation for both global and glycoproteomic analyses by two dimensional fractionation followed by LC–MS/MS analysis using a Orbitrap Velos mass spectrometer. Results Proteins and N-linked glycosite-containing peptides were identified and quantified using the integrated global proteomic and glycoproteomic approach. Among the identified N-linked glycosite-containing peptides, the relative abundances of glycosite-containing peptide and the glycoprotein levels were compared using glycoproteomic and proteomic data. The glycosite-containing peptides with unique changes in glycosylation occupancies rather than the protein expression levels were identified. Conclusion In this study, we presented an integrated proteomics and glycoproteomics approach to identify changes of glycoproteins in protein expression and glycosylation occupancy in HGSC and serous cystadenoma and determined the changes of glycosylation occupancy that are associated with malignant and benign tumor tissues. Specific changes in glycoprotein expression or glycosylation occupancy have the potential to be used in the discrimination between benign and malignant epithelial ovarian tumors and to improve our understanding of ovarian cancer biology. Electronic supplementary material The online version of this article (doi:10.1186/s12014-017-9152-2) contains supplementary material, which is available to authorized users.

Recurrent respiratory papillomatosis (RRP) is a benign disease caused by human papillomavirus (HPV) types 6 and 11. Although a prophylactic vaccine against RRP is available, a therapeutic vaccine is needed to treat those already infected. The objective of our study was to design and test a DNA vaccine targeting HPV11 proteins.Preclinical scientific investigation.A DNA vaccine encoding the HPV11 E6 and E7 genes linked to calreticulin (CRT) was generated. Immunologic response to the HPV11 CRT/E6E7 vaccine was measured by vaccinating C57BL/6 mice via electroporation and measuring CD8 + T cell responses from harvested splenocytes. A tumor cell line containing HPV11-E6E7 was created, and the ability of novel DNA vaccine to control tumor growth was measured in vivo.Our vaccine generated a significant and specific CD8 + T-cell response against the HPV11-E6aa41-70 peptide. The CD8 + T-cell responses did not recognize E7 epitopes, indicating E6 immunodominance. CD8 + responses were augmented in the CRT-linked vaccine compared to a control non-CRT vaccine. The HPV11 CRT/E6E7 vaccine was used to treat mice inoculated with a HPV11 E6E7 expressing tumor cell line after temporary CD3 depletion to facilitate tumor growth. Vaccinated mice had a significantly lower tumor growth rate (P = .029) and smaller tumor volumes compared to control mice, indicating an augmented immunologic response in vaccinated mice.A DNA vaccine targeting HPV11 E6E7 generates a specific HPV11 CD-8 + T-cell response capable of reducing the growth of HPV11-expressing tumors. DNA vaccines are a promising immunologic strategy for treating RRP.NA. Laryngoscope, 127:2713-2720, 2017.

Although it has been shown that prophylactic vaccination can induce genital immunity, there is inadequate information on human papillomavirus (HPV) vaccine-induced oral immunity, which is of particular interest due to HPV-associated oropharyngeal malignancies and recurrent respiratory papillomatosis. Therefore, we assessed the efficacy of various HPV vaccines against oral HPV pseudovirus (PsV) infection in mice.Preclinical scientific investigation.C57BL/6 mice were vaccinated three times at 2-week intervals with either Gardasil (Merck, Kenilworth, NJ) (50 µL intramuscular injection) or a candidate pan-HPV L2 vaccine with alum adjuvant (25 µg subcutaneous injection). Additional mice were immunized with passive transfer of either Gardasil (Merck) human antisera or nonimmunized sera (100 µL intraperitoneal injection). All vaccinated and naïve control mice were then challenged with HPV16 E6E7 luciferase PsV in the oral mucosa. Visualization of HPV PsV infection was monitored through in vivo luciferase imaging.Oral luciferase-expressing HPV16 PsV infection was not detected in Gardasil (Merck), L2 vaccine, and Gardasil (Merck) antisera-immunized mice, whereas robust luciferase expression was observed in all control mice. An in vitro neutralization assay from sera of Gardasil-vaccinated (Merck) mice confirmed that vaccine efficacy was due to neutralizing antibodies.Oral HPV16 PsV infection in mice was completely prevented with all methods of prophylactic HPV immunization. These findings provide preliminary evidence that human vaccines induce protection against oral HPV infection, which has significant public health implications for HPV-associated oropharyngeal malignancies.NA. Laryngoscope, 128:E16-E20, 2018.

To investigate whether tumor cells could be detected in the vagina of women with serous ovarian cancer through TP53 analysis of DNA samples collected by placement of a vaginal tampon.Women undergoing surgery for a pelvic mass were identified in the gynecologic oncology clinic. They placed a vaginal tampon before surgery, which was removed in the operating room. Cells were isolated and DNA was extracted from both the cells trapped within the tampon and the primary tumor. In patients with serous carcinoma, the DNA was interrogated for the presence of TP53 mutations using a method capable of detecting rare mutant alleles in a mixture of mutant and wild-type DNA.Thirty-three patients were enrolled. Eight patients with advanced serous ovarian cancer were included for analysis. Three had a prior tubal ligation. TP53 mutations were identified in all eight tumor samples. Analysis of the DNA from the tampons revealed mutations in three of the five patients with intact tubes (sensitivity 60%) and in none of the three patients with tubal ligation. In all three participants with mutation detected in the tampon specimen, the tumor and the vaginal DNA harbored the exact same TP53 mutation. The fraction of DNA derived from exfoliated tumor cells ranged from 0.01% to 0.07%.In this pilot study, DNA derived from tumor was detected in the vaginas of 60% of patients with ovarian cancer with intact fallopian tubes. With further development, this approach may hold promise for the early detection of this deadly disease.

Immunization with human papillomavirus (HPV) L1 virus-like particles (VLPs) prevents infection with HPV. However, the expense and logistical demands of current VLP vaccines will limit their widespread use in resource-limited settings, where most HPV-induced cervical cancer occurs. Live oral adenovirus vaccines have properties that are well-suited for use in such settings. We have described a live recombinant adenovirus vaccine prototype that produces abundant HPV16 L1 protein from the adenovirus major late transcriptional unit and directs the assembly of HPV16 VLPs in tissue culture. Recombinant-derived VLPs potently elicit neutralizing antibodies in mice. Here, we characterize the immune response to the recombinant after dual oral and intranasal immunization of pigtail macaques, in which the virus replicates as it would in immunized humans. The immunization of macaques induced vigorous humoral responses to adenovirus capsid and nonstructural proteins, although, surprisingly, not against HPV L1. In contrast, immunization elicited strong T-cell responses to HPV VLPs as well as adenovirus virions. T-cell responses arose immediately after the primary immunization and were boosted by a second immunization with recombinant virus. T-cell immunity contributes to protection against a wide variety of pathogens, including many viruses. The induction of a strong cellular response by the recombinant indicates that live adenovirus recombinants have potential as vaccines for those agents. These studies encourage and will inform the continued development of viable recombinant adenovirus vaccines.

Objective To examine the value of individual and combinations of ovarian cancer associated blood biomarkers for the discrimination between plasma of patients with type I or II ovarian cancer and disease-free volunteers. Methods Levels of 14 currently promising ovarian cancer-related biomarkers, including CA125, macrophage inhibitory factor-1 (MIF-1), leptin, prolactin, osteopontin (OPN), insulin-like growth factor-II (IGF-II), autoantibodies (AAbs) to eight proteins: p53, NY-ESO-1, p16, ALPP, CTSD, B23, GRP78, and SSX, were measured in the plasma of 151 ovarian cancer patients, 23 with borderline ovarian tumors, 55 with benign tumors and 75 healthy controls. Results When examined individually, seven candidate biomarkers (MIF, Prolactin, CA-125, OPN, Leptin, IGF-II and p53 AAbs) had significantly different plasma levels between type II ovarian cancer patients and healthy controls. Based on the receiver operating characteristic (ROC) curves constructed and area under the curve (AUC) calculated, CA125 exhibited the greatest power to discriminate the plasma samples of type II cancer patients from normal volunteers (AUC 0.9310), followed by IGF-II (AUC 0.8514), OPN (AUC 0.7888), leptin (AUC 0.7571), prolactin (AUC 0.7247), p53 AAbs (AUC 0.7033), and MIF (AUC 0.6992). p53 AAbs levels exhibited the lowest correlation with CA125 levels among the six markers, suggesting the potential of p53 AAbs as a biomarker independent of CA125. Indeed, p53 AAbs increased the AUC of ROC curve to the greatest extent when combining CA125 with one of the other markers. At a fixed specificity of 100%, the addition of p53 AAbs to CA125 increased sensitivity from 73.8% to 85.7% to discriminate type II cancer patients from normal controls. Notably, seropositivity of p53 AAbs is comparable in type II ovarian cancer patients with negative and positive CA125, but has no value for type I ovarian cancer patients. Conclusions p53 AAbs might be a useful blood-based biomarker for the detection of type II ovarian cancer, especially when combined with CA125 levels.

Objective To address the hypothesis that type II ovarian carcinoma, mutation of p53 and plasma levels of particular cytokines are associated with the generation of p53-specific serum autoantibody (AAb) responses in patients. Methods Levels of CA125, 17 cytokines and AAbs to tumor-associated antigens including p53 were measured in plasma of 130 gynecologic tumor patients and 84 healthy controls. TP53 exons 4–9 were sequenced in tumor specimens. Results p53 AAbs are associated with high grade, but not low grade ovarian carcinoma. Seropositivity for p53 AAb occurred only in those ovarian carcinoma patients whose tumors contained mutated TP53 , regardless of the exon targeted. Higher p53 AAb levels were detected in ovarian carcinoma patients who had higher stage disease, but p53 AAb levels were not correlated with CA125 levels. Among high-grade carcinoma patients, there was no relationship between p53 AAb seropositivity and seropositivity to other tumor-associated antigens tested, CA125 level or survival outcome. Both high and low grade ovarian carcinoma patients exhibited elevated levels of IL6, IL8 and IL10 as compared to healthy volunteers, although increased levels of IL5, MCP1, MIP1 and TNFα were associated only with high grade and advanced disease. Higher levels of p53AAb responses were correlated with elevated circulating IL4 and IL12, but reduced IL8 levels. Conclusion Type II, but not type I, ovarian carcinoma patients had elevated serum levels of p53 AAb. P53 AAb is associated with mutation of TP53 , higher plasma IL4 and IL12 but lower plasma IL8 levels and no survival advantage.

Background Infection by any one of 15 high risk human papillomavirus (hrHPV) types causes most invasive cervical cancers. Their oncogenic genome is encapsidated by L1 (major) and L2 (minor) coat proteins. Current HPV prophylactic vaccines are composed of L1 virus-like particles (VLP) that elicit type restricted immunity. An N-terminal region of L2 protein identified by neutralizing monoclonal antibodies comprises a protective epitope conserved among HPV types, but it is weakly immunogenic compared to L1 VLP. The major antigenic capsid protein of adenovirus type 5 (Ad5) is hexon which contains 9 hypervariable regions (HVRs) that form the immunodominant neutralizing epitopes. Insertion of weakly antigenic foreign B cell epitopes into these HVRs has shown promise in eliciting robust neutralizing antibody responses. Thus here we sought to generate a broadly protective prophylactic HPV vaccine candidate by inserting a conserved protective L2 epitope into the Ad5 hexon protein for VLP-like display. Methods Four recombinant adenoviruses were generated without significant compromise of viral replication by introduction of HPV16 amino acids L2 12–41 into Ad5 hexon, either by insertion into, or substitution of, either hexon HVR1 or HVR5. Results Vaccination of mice three times with each of these L2-recombinant adenoviruses induced similarly robust adenovirus-specific serum antibody but weak titers against L2. These L2-specific responses were enhanced by vaccination in the presence of alum and monophoryl lipid A adjuvant. Sera obtained after the third immunization exhibited low neutralizing antibody titers against HPV16 and HPV73. L2-recombinant adenovirus vaccination without adjuvant provided partial protection of mice against HPV16 challenge to either the vagina or skin. In contrast, vaccination with each L2-recombinant adenovirus formulated in adjuvant provided robust protection against vaginal challenge with HPV16, but not against HPV56. Conclusion We conclude that introduction of HPV16 L2 12–41 epitope into Ad5 hexon HVR1 or HVR5 is a feasible method of generating a protective HPV vaccine, but further optimization is required to strengthen the L2-specific response and broaden protection to the more diverse hrHPV.

Causality requires a judgment based on scientific evidence from human and experimental studies, as strict causality studies are often not appropriate in humans. Evidence linking certain human papillomavirus (HPV) genotypes to cervical carcinoma is extensive and compelling. More than two decades of research has led to the fulfillment of criteria, as proposed by Hill, to establish a causal link between high risk HPV infection and cervical cancer (Table 1). HPV DNA was first isolated from biopsies of cervical cancer more than 30 years ago (1, 2). HPV DNA is detected in 99.7% of cervical carcinomas worldwide. The evidence overwhelmingly demonstrates that persistent high risk HPV infection is a necessary but not sufficient cause of this cancer (3).

Background: Prospective cohort studies have reported spontaneous regression rates of high-grade cervical intraepithelial Neoplasia (CIN2/3) close to 35%, over a period of 4-6 months. These regressions are presumably immunologically mediated. It is now well recognized that PD-L1 is an immune checkpoint used by neoplastic cells to evade the immune system, particularly T cells that are specific for tumor antigens. PD-L1 and several other immune checkpoints consist of inhibitory pathways that tightly regulate the immune system to control the duration and amplitude of immune responses in peripheral tissues in order to minimize collateral tissue damage. Design: Immunohistochemistry with anti-TBX21 and anti-PD-L1 antibodies was performed in formalin-fixed paraffin-embedded tissue sections from a tissue microarray consisting of invasive cervical carcinomas (ICCs) (n = 22), CIN2/3 (n = 4) and benign cervical tissues (n = 4). Expression of TBX21 and PD-L1 was reviewed and scored by a trained pathologist blinded to the clinical outcome of each case. Statistical correlations between these markers’ score and available demographic and clinicopathologic data from each case were performed, as well as disease-free survival curves. Moreover, PD-L1 staining was performed in three patients with CIN2/3 that received peripheral (IM) therapeutic HPV vaccination. PD-L1 expression differences in pre and post-vaccination tissues were compared. Results: Increased expression of TBX21+ T-cells and PD-L1 was observed from benign to CIN2/3 to ICCs. Association analysis (fisher exact test) showed a significant correlation between increased intraepithelial and stromal infiltration of TBX21+ T-cells (score 2,3) and higher PD-L1 membrane expression (p = 0.04 and p = 0.005, respectively). No significant associations were found between PD-L1 expression and demographic and clinicopathologic information, likely due to small number of samples. In our vaccine cohort, we observed a stronger membrane PD-L1 expression in the epithelium and stroma of the post-vaccination tissue compared to the pre-vaccination biopsy. Conclusion: Increased membrane expression of PD-L1 is tightly correlated with an increased epithelial and stromal infiltration of TBX21+ T cells in CIN2/3 and ICCs. This correlation was also observed in our vaccination cohort when compared to our previous published findings of immune activation after HPV therapeutic vaccination. This association could represent an immune response control mechanism induced presumably by interferons released by TBX21+ T cells. We are currently evaluating the expression of PD-L1 and B7-H4, a recently discovered inhibitory ligand, in a larger cohort of benign, CIN2/3 and ICCs. Finally, we will further explore, quantitate and compare the expression changes of these immune checkpoints in the remaining CIN2/3 cases of our vaccination cohort (n = 12) in pre and post-vaccination tissues. Citation Format: Leonel F. Maldonado Gonzalez, Christopher VandenBussche, Richard Roden, T.C. Wu, Benjamin Tycko, Cornelia L. Trimble. PD-L1: the hand brake of immune responses in cervical intraepithelial neoplasia and cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1320. doi:10.1158/1538-7445.AM2015-1320

The identification of human papillomavirus (HPV) as a cause of cervical cancer and its precursor lesions indicates that HPV vaccines can potentially be used to prevent or treat cervical cancer and other HPV-associated malignancies. Prophylactic HPV vaccines aim to prevent infection by producing neutralizing antibodies against HPV capsid proteins L1 and L2. However, because HPV-infected basal keratinocytes and HPV-transformed cells generally do not express L1 or L2, therapeutic HPV vaccines are being developed to treat established HPV infections and HPV-associated malignancies by targeting non-structural early viral antigens of HPV, such as E6 and E7 (two viral oncogenic proteins required for the induction and maintenance of malignant cancer). Results from preclinical HPV vaccine studies have led to several HPV vaccine clinical trials. If these prophylactic and therapeutic HPV vaccines prove as successful in patients as they have in animal models, HPV vaccines may have a role in the control of HPV infection and HPV-associated disease.

Cervical cancer continues to be the second largest cause of cancer deaths in women worldwide. Persistent infection with high-risk types of human papillomavirus (HPV) is a necessary cause of cervical cancer. Thus, prophylactic vaccination against HPV is an attractive strategy to prevent cervical cancer. Current strategies for the development of safe and effective preventive vaccines are based on the induction of neutralizing antibodies against the major capsid protein, L1 of HPV. Cervarix™ is one of the preventive HPV vaccines that has been approved in the Europe and Australia and is currently under review by the US Food and Drug Administration. Cervarix is composed of HPV16 and HPV18 L1 virus-like particles (VLPs) formulated in ASO4 adjuvant. Vaccination with Cervarix has been shown to protect women against a high proportion of precursor lesions of cervical cancer caused by these two HPV types. This review explores the various features of this new vaccine candidate and discusses the future directions in the field of HPV vaccine development.