Regulation of immune responses to HPV infection and during HPV-directed immunotherapy

Decoding the influence of the immune system and immunotherapy targets on carcinomas: A hidden prism in oral cancer therapy

In recent decades, understanding tumorigenesis and the complex interaction between the host and the immune system has been the pillar for significant advances in anticancer therapy. Conventional anticancer therapy (e.g., cut, burn, and cytotoxic drugs) involves multiple targeting of tumor cells. However, the tumor tissue microenvironment can present a dysregulated, stimulating, or subverted immune response which, in turn, reveals pro-tumor activities favoring tumor expansion and progression. Recently, new potential targets have been identified based on immunomodulatory therapies, which are crafted to re-establish the host anti-tumoral immune response. Clinicians should fully understand the intricate interactions between carcinogens, the tumor milieu, the immune system, and traditional anticancer therapies in order to progress and to overcome the refractory/recurrent challenges and morbidity of the disease. Thus, in this article, we highlight the complex milieu of the oral cancer immune response, pointing out potential therapeutic immunotargets for oral squamous cell carcinomas. The impact of traditional anticancer therapy on the immune system is also outlined.

Combinations of immunotherapy and radiation therapy in head and neck squamous cell carcinoma: a narrative review

Radiation therapy and systemic therapy are the primary non-surgical treatment modalities for head and neck squamous cell carcinoma (HNSCC). Despite advances in our biologic understanding of this disease and the development of novel therapeutics, treatment resistance remains a significant problem. It has become increasingly evident that the innate and adaptive immune systems play a significant role in the modulation of anti-tumor responses to traditional cancer-directed therapies. By inducing DNA damage and cell death, radiation therapy appears to activate both innate and adaptive immune responses. Immunotherapies targeting programmed cell death protein 1 (PD-1) and programmed cell death ligand 1 (PD-L1) also have yielded promising results, particularly in the recurrent/metastatic setting. In this review, we will discuss the rationale for combining radiotherapy with immunotherapy to harness the immunomodulatory effects of radiation therapy on HNSCC, as well as biomarkers for immune response. We will also review recent preclinical and clinical data exploring these combinations in various contexts, including recurrent/metastatic and locally advanced disease. Among those with locally advanced HNSCC, we will discuss clinical trials employing immunotherapy either concurrently with radiation therapy or as maintenance following chemoradiation in both the definitive and postoperative settings, with or without the use of cisplatin-based or non-cisplatin-based chemotherapy.

Human Papillomavirus (HPV)-Associated Squamous Cell Carcinoma In situ With Positive p16 and Ki-67 Immunohistochemical Stains in a Young Immunocompetent Patient

There is an oncogenic role of human papillomavirus (HPV) in the development of premalignant and malignant skin cancers, especially squamous cell carcinomas (SCCs). Some of the major risk factors for SCC include older age, fair skin types, immunosuppression, ultraviolet radiation (UVR), history of epidermodysplasia verruciformis (EV), and co-carcinogenesis by the HPV. Our case report exemplifies a unique case of a low-risk, 34-year-old female who developed an HPV-associated squamous cell carcinoma in situ (SCCIS) on her left palmar hand, despite having none of the contributing risk factors. The biopsy also showed full-thickness keratinocyte atypia and increased mitotic activity throughout all the layers of the epidermis. Immunohistochemical stains showed strong and diffuse nuclear staining of p16 and Ki-67 throughout the SCCIS, confirming HPV etiology. We speculate that tumor development in our patient relied on the combined effects of UVR exposure, localized immunosuppression, and the co-carcinogenic effects of HPV infection.

HPV-Specific Systemic Antibody Responses and Memory B Cells are Independently Maintained up to 6 Years and in a Vaccine-Specific Manner Following Immunization with Cervarix and Gardasil in Adolescent and Young Adult Women in Vaccination Programs in Italy

Human papillomavirus (HPV) persistent infections are associated with cervical cancer and other HPV-related diseases and tumors. Thus, the characterization of long lasting immunity to currently available HPV vaccines is important. A total of 149 female subjects vaccinated with Cervarix or Gardasil participated to the study and they were stratified according to age (10–12-year-old and 16–20-year-old). Humoral immune responses (IgG and neutralizing antibody titers, antibody avidity) and circulating memory B cells were analyzed after an average of 4–6 years from the third immunization. The humoral responses against HPV-16 and HPV-18 (and HPV-6 and HPV-11 for Gardasil) were high in both age groups and vaccines up to six years from the third dose. However, Cervarix induced significantly higher and more persistent antibody responses, while the two vaccines were rather equivalent in inducing memory B cells against HPV-16 and HPV-18. Moreover, the percentage of subjects with vaccine-specific memory B cells was even superior among Gardasil vaccinees and, conversely, Cervarix vaccinated individuals with circulating antibodies, but undetectable memory B cells were found. Finally, a higher proportion of Cervarix-vaccinated subjects displayed cross-neutralizing responses against non-vaccine types HPV-31 and HPV-45. Gardasil and Cervarix may, thus, differently affect long-lasting humoral immunity from both the quantitative and qualitative point of view.

Safety and efficacy of mucosal immunotherapy using human papillomavirus (HPV) type 16 E7-expressing Lactobacillus-based vaccine for the treatment of high-grade squamous intraepithelial lesion (HSIL): the study protocol of a randomized placebo-controlled clinical trial (MILACLE study)

We developed an HPV16 E7-expressing Lactobacillus-based therapeutic vaccine, IGMKK16E7, to elicit mucosal E7-specific TH1 cellular immune responses. This study aims to examine the safety and clinical efficacy of IGMKK16E7 on HPV16-positive high-grade squamous intraepithelial lesion (HSIL). This is a multicenter, placebo-controlled, double-blind randomized phase I/II trial to test the safety and efficacy of IGMKK16E7 against HPV16-positive HSIL. The groups will include placebo, low-dose (0.5 g/day), middle-dose (1 g/day), and high-dose (1.5 g/day) IGMKK16E7. The target sample size will be 41 patients per group, and our data on our former agent, GLBL101c, were used to calculate sample size for 70% power and an α level = 0.05. The primary endpoint is IGMKK16E7 safety and pathological regression at week 16, and the secondary endpoints are cytological regression and HPV16 E7 immunological response. This study protocol has been approved by the Japanese Pharmaceuticals and Medical Devices Agency. Patient enrollment will begin in May 2019.

Interleukin-17 expression in the serum and exfoliated cervical cells of patients infected with high-risk oncogenic human papillomavirus

Persistent infection by high-risk oncogenic human papillomavirus (HR-HPV) is the main cause of cervical cancer and its precursor lesions, and both the systemic and local immunological responses play an important role in eliminating or maintenance this infection. Th17 cells, as well as interleukin (IL)-17, are related to tumor growth and persistence of viral infection. Thus, this study aimed to quantify IL-17 in the serum and exfoliated cervical cells of HR-HPV-infected patients and healthy patients as well as identify CD4⁺IL17⁺ cells and IL-17 production in uterine cervix biopsies to better understand the behavior of this cytokine in HPV infections. IL-17 was quantified (pg/mL) in the serum and exfoliated cervical cells of 26 HR-HPV-infected patients, and in 18 healthy patients, using flow cytometry. Fifteen paraffin-embedded biopsy samples from the uterine cervix were subjected to immunohistochemistry to detect CD4⁺IL-17⁺ and IL-17⁺ cells. There was a significant increase in the concentration of IL-17 in HR-HPV-positive patients' serum when compared to that in samples of exfoliated cervical cells (p < 0.05). Likewise, when compared with that in healthy patients, the IL-17 concentration was still higher in HR-HPV-positive patients sera (p < 0.05). We did not find differences in the amount of CD4⁺IL-17⁺ cells and other IL-17-secreting cells between different histopathological lesions. Our results suggest that HR-HPV infection predominantly stimulates systemic IL-17 production along with less localized expression.

HPV-Mediated Resistance to TNF and TRAIL Is Characterized by Global Alterations in Apoptosis Regulatory Factors, Dysregulation of Death Receptors, and Induction of ROS/RNS

Persistent infection with high-risk human papilloma virus (HR-HPV) is the main risk factor for the development of invasive cervical cancer although is not sufficient to cause cervical cancer. Several host and environmental factors play a key role in cancer initiation/progression, including cytokines and other immune-response mediators. Here, we characterized the response to the individual and combined action of the pro-inflammatory cytokines tumor necrosis factor (TNF) and TNF-related apoptosis-inducing ligand (TRAIL) on HPV-transformed cells and human keratinocytes ectopically expressing E6 and E7 early proteins from different HPV types. We showed that keratinocytes expressing HPV early proteins exhibited global alterations in the expression of proteins involved in apoptosis regulation/execution, including TNF and TRAIL receptors. Besides, we provided evidence that TNF receptor 1 (TNFR1) was down-regulated and may be retained in the cytoplasm of keratinocytes expressing HPV16 oncoproteins. Finally, fluorescence analysis demonstrated that cytokine treatment induced the production and release of reactive oxygen and nitrogen species (ROS/RNS) in cells expressing HPV oncogenes. Alterations in ROS/RNS production and apoptosis regulatory factors expression in response to inflammatory mediators may favor the accumulation of genetic alterations in HPV-infected cells. Altogether, our results suggested that these events may contribute to lesion progression and cancer onset.

Association of cervical microbial community with persistence, clearance and negativity of Human Papillomavirus in Korean women: a longitudinal study

The present study aimed to identify the cervical microbes that are associated with HPV negativity, HPV clearance and HPV persistence and to assess the microbes’ longitudinal associations as related to HPV infection dynamics among Korean women. We enrolled 41 women with 107 samples, and classified them according to the HPV infection dynamics: HPV negativity (21 samples, 10 subjects), HPV clearance (42 samples, 15 subjects), and HPV persistence (44 samples, 16 subjects). Cervical swabs were collected at the baseline and six-month-interval follow-up visits. HPV positivity was determined by HPV DNA HC2 assay, and the microbiome was analyzed using 16SrRNA pyrosequencing, linear discriminant analysis effect size and multivariate logistic analysis. In the multivariate logistic analysis results, Lactobacillus crispatus (multivariate OR (mOR) = 8.25, 95% CI 2.13~32.0) was predominant in the HPV-negative group. We observed that Eubacterium eligens (mOR = 11.5, 95% CI 1.31~101.4), Gardnerella vaginalis (mOR = 17.0, 95% CI 2.18–131.8), and Ureaplasma urealyticum (mOR = 7.42, 95% CI 1.3–42.46) had the strongest associations with HPV clearance, and Lactobacillus johnsonii (mOR = 16.4, 95% CI 1.77–152.2) with HPV persistence. Overall, greater diversity was observed in HPV-persistence than in HPV-negative women. Our findings suggest that the presence and prevalence of a specific cervical microbiome are factors involved in HPV dynamics.

Epidemiology and biology of cutaneous human papillomavirus

Cutaneous human papillomaviruses (HPVs) include β- and γ-HPVs, in addition to a small fraction of α-HPVs. β-HPVs were first isolated from patients with the rare genetic disorder Epidermodysplasia verruciformis, and they are associated with the development of nonmelanoma skin cancer at sun-exposed skin sites in these individuals. Organ transplant recipients also have greater susceptibility to β-HPV infection of the skin and an increased risk of developing nonmelanoma skin cancer. In both immunosuppressed and immunocompromised individuals, cutaneous HPVs are ubiquitously disseminated throughout healthy skin and may be an intrinsic part of the commensal flora. Functional analysis of E6 and E7 proteins of specific cutaneous HPVs has provided a mechanistic comprehension of how these viruses may induce carcinogenesis. Nevertheless, additional research is crucial to better understand the pathological implications of the broad distribution of these HPVs.

Human papillomavirus E7 oncoprotein expression by keratinocytes alters the cytotoxic mechanisms used by CD8 T cells

Cervical cancer is a malignant transformation of keratinocytes initiated by the E7 oncoprotein of human papillomavirus (HPV). These tumors are characterized by keratinocyte hyperproliferation and are often infiltrated with activated CD8 T cells. HPV infection confers changes to gain immunological advantage to promote chronic infection, and these persist with malignant transformation. We investigated the relative importance of the many redundant mechanisms of cytotoxicity used by CD8 T cells to kill keratinocytes expressing HPV E7 oncoprotein using extended-duration time-lapse microscopy that allows examination of cell-to-cell interactions during killing. E7 expression by keratinocytes increased susceptibility to cell-mediated killing. However, while killing of non-transgenic keratinocytes was traditional, perforin-mediated, and caspase-dependent, E7-expression favored killing by perforin-independent, caspase-independent mechanisms. The roles of perforin, TNFα, IFNγ, Fas/FasL and PD1/PD-L1 were graded according to target cell survival to produce a hierarchy of killing mechanisms utilized in killing E7-expressing cells. TNFα was essential for perforin-mediated killing of E7-expressing cells, but not perforin-independent killing. IFNγ facilitated killing by Fas/FasL interaction, especially in the absence of perforin. Additionally, expression of E7 offered protection from killing by up regulation of PD-L1, Fas and FasL expression on keratinocytes promoting fight-back by target cells, resulting in effector cell death. This study shows that keratinocytes expressing E7 are highly susceptible to killing by CD8 T cells, but utilizing different armamentarium. Down-regulation of CD8 T cell cytotoxicity in HPV-related tumors may be due to suppression by E7-expressing keratinocytes. Immunotherapy for HPV-related cancers may be improved by suppression of PD-L1, or by suppression of FasL.

Vaccination with High-Affinity Epitopes Impairs Antitumor Efficacy by Increasing PD-1 Expression on CD8+ T Cells

Antitumor vaccines encoding self-antigens generally have low immunogenicity in clinical trials. Several approaches are aimed at improving vaccine immunogenicity, including efforts to alter encoded epitopes. Immunization with epitopes altered for increased affinity for the major histocompatibility complex (MHC) or T-cell receptor (TCR) elicits greater numbers of CD8 T cells but inferior antitumor responses. Our previous results suggested that programmed death 1 (PD-1) and its ligand (PD-L1) increased on antigen-specific CD8 T cells and tumor cells, respectively, after high-affinity vaccination. In this report, we use two murine models to investigate whether the dose, MHC affinity, or TCR affinity of an epitope affected the antitumor response via the PD-1/PD-L1 axis. T cells activated with high-affinity epitopes resulted in prolonged APC:T-cell contact time that led to elevated, persistent PD-1 expression, and expression of other checkpoint molecules, in vitro and in vivo Immunization with high-affinity epitopes also decreased antitumor efficacy in the absence of PD-1 blockade. Thus, APC:T-cell contact time can be altered by epitope affinity and lead to therapeutically relevant changes in vaccine efficacy mediated by changes in PD-1 expression. These findings have implications for the use of agents targeting PD-1 expression or function whenever high-affinity CD8 T cells are elicited or supplied by means of vaccination or adoptive transfer. Cancer Immunol Res; 5(8); 630-41. ©2017 AACR.

Targeted Therapy in Head and Neck Cancer: An Update on Current Clinical Developments in Epidermal Growth Factor Receptor-Targeted Therapy and Immunotherapies

Most patients diagnosed with head and neck squamous cell carcinoma (HNSCC) will present with locally advanced disease, requiring multimodality therapy. Despite this curative approach, a significant subset of these patients will develop locoregional failure and/or distant metastases. Despite significant progress in the treatment and subsequent prognosis of locally advanced HNSCC, the prognosis of those patients with recurrent and/or metastatic (R/M) HNSCC is poor, with short-lived responses to palliative chemotherapy and few therapeutic agents available. The discovery of the integral role of epidermal growth factor receptor overexpression in the pathogenesis of HNSCC, coupled with emerging data on the role of tumor evasion of the immune system, has opened new pathways in the development of novel therapeutic agents for the treatment of R/M HNSCC. As a result, cetuximab, a monoclonal antibody targeting epidermal growth factor receptor, as well as pembrolizumab and nivolumab, monoclonal antibodies targeting programmed cell death 1 (PD-1), are now US Food and Drug Administration approved for the treatment of R/M HNSCC. This review will detail the data supporting the use of these agents, as well as clinical trials evaluating the efficacy of other novel and promising drugs.

HPV16-E7-Specific Activated CD8 T Cells in E7 Transgenic Skin and Skin Grafts

Human papillomavirus (HPV) 16 E7 (E7) protein expression in skin promotes epithelial hyperproliferation and transformation to malignancy. Grafts of murine skin expressing E7 protein as a transgene in keratinocytes are not rejected from immunocompetent recipients, whereas grafts expressing ovalbumin (OVA), with or without coexpression of E7 protein, are promptly rejected, demonstrating that E7-associated non-antigen-specific local immunosuppression is not a major determinant of lack of rejection of E7 transgenic skin. To determine whether failure of rejection of E7 skin grafts is due to failure to attract E7-specific effector T cells, E7- and OVA-specific effector CD8⁺ T cells, activated in vitro, were transferred to animals bearing E7 transgenic skin grafts. Three days after T cell transfer, E7-specific T cells were present in significantly greater numbers than OVA-specific T cells in the grafted skin on animals bearing recently placed or healed E7 grafts, without graft rejection, and also in the ear skin of E7 transgenic animals, without obvious pathology. E7 and OVA-specific T cells were present in lesser numbers in healed E7 grafts than in recently placed grafts and in lesser numbers in recently placed E7 transgenic epidermal grafts without E7-associated hyperproliferation, derived from E7 transgenic mice with a mutated retinoblastoma gene. These data demonstrate that effector T cells are to some extent attracted to E7 transgenic skin specifically by E7 expression, but in large measure non-specifically by the epithelial proliferation associated with E7 expression, and by the local inflammation produced by grafting. Failure of E7 graft rejection was observed despite trafficking of E7-specific effector T cells to E7-expressing epithelium, a finding of consequence for immunotherapy of HPV 16 E7-associated human cancers.

Targeting of HPV-16+ Epithelial Cancer Cells by TCR Gene Engineered T Cells Directed against E6

PURPOSE

The E6 and E7 oncoproteins of HPV-associated epithelial cancers are in principle ideal immunotherapeutic targets, but evidence that T cells specific for these antigens can recognize and kill HPV(+) tumor cells is limited. We sought to determine whether TCR gene engineered T cells directed against an HPV oncoprotein can successfully target HPV(+) tumor cells.

EXPERIMENTAL DESIGN

T-cell responses against the HPV-16 oncoproteins were investigated in a patient with an ongoing 22-month disease-free interval after her second resection of distant metastatic anal cancer. T cells genetically engineered to express an oncoprotein-specific TCR from this patient's tumor-infiltrating T cells were tested for specific reactivity against HPV(+) epithelial tumor cells.

RESULTS

We identified, from an excised metastatic anal cancer tumor, T cells that recognized an HLA-A*02:01-restricted epitope of HPV-16 E6. The frequency of the dominant T-cell clonotype from these cells was approximately 400-fold greater in the patient's tumor than in her peripheral blood. T cells genetically engineered to express the TCR from this clonotype displayed high avidity for an HLA-A*02:01-restricted epitope of HPV-16, and they showed specific recognition and killing of HPV-16(+) cervical, and head and neck cancer cell lines.

CONCLUSIONS

These findings demonstrate that HPV-16(+) tumors can be targeted by E6-specific TCR gene engineered T cells, and they provide the foundation for a novel cellular therapy directed against HPV-16(+) malignancies, including cervical, oropharyngeal, anal, vulvar, vaginal, and penile cancers.

Immunology and Immunotherapy of Head and Neck Cancer

The immune system plays a key role in the development, establishment, and progression of head and neck squamous cell carcinoma (HNSCC). A greater understanding of the dysregulation and evasion of the immune system in the evolution and progression of HNSCC provides the basis for improved therapies and outcomes for patients. HNSCC cells evade the host immune system through manipulation of their own immunogenicity, production of immunosuppressive mediators, and promotion of immunomodulatory cell types. Through the tumor's influence on the microenvironment, the immune system can be exploited to promote metastasis, angiogenesis, and growth. This article provides a brief overview of key components of the immune infiltrating cells in the tumor microenvironment, reviewing immunological principles related to head and neck cancer, including the concept of cancer immunosurveillance and immune escape. Current immunotherapeutic strategies and emerging results from ongoing clinical trials are presented.

Recent progress in vaccination against human papillomavirus-mediated cervical cancer

It has been more than 7 years since the commercial introduction of highly successful vaccines protecting against high-risk human papillomavirus (HPV) subtypes and the development of cervical cancer. From an immune standpoint, the dependence of cervical cancer on viral infection has meant that HPV proteins can be targeted as strong tumour antigens leading to clearance of the infection and the subsequent protection from cancer. Commercially available vaccines consisting of the L1 capsid protein assembled as virus-like particles (VLPs) induce neutralising antibodies that deny access of the virus to cervical epithelial cells. While greater than 90% efficacy has been demonstrated at the completion of large phase III trials in young women, vaccine developers are now addressing broader issues such as efficacy in boys, longevity of the protection and inducing cross-reactive antibody for oncogenic, non-vaccine HPV strains. For women with existing HPV infection, the prophylactic vaccines provide little protection, and consequently, the need for therapeutic vaccines will continue into the future. Therapeutic vaccines targeting HPVE6 and E7 proteins are actively being pursued with new adjuvants and delivery vectors, combined with an improved knowledge of the tumour microenvironment, showing great promise. This review will focus on recent progress in prophylactic and therapeutic vaccine development and implementation since the publication of end of study data from phase III clinical trials between 2010 and 2012.

Factors associated with visible anogenital warts among HIV-uninfected Peruvian men who have sex with men and transwomen: a cross-sectional study

BACKGROUND

Visible, anogenital warts may be associated with risk factors for HIV infection. This cross-sectional study examined the factors associated with visible anogenital warts among HIV-uninfected Peruvian men who have sex with men (MSM) and transwomen.

METHODS

Six hundred HIV-uninfected MSM and transwomen were recruited from a community-based setting in metropolitan Lima, Peru, through outreach activities. Participants were tested for syphilis, completed a behavioral questionnaire, and were examined for visible anogenital warts. Logistic regression was used to assess the independent association between sample characteristics, HIV-related risk factors, and visible anogenital warts.

RESULTS

A tertiary education versus a primary/secondary (adjusted odds ratio [AOR], 1.79; 95% confidence interval [CI], 1.07-2.99), a first experience of anal intercourse at age 20 years or older versus younger ages (AOR, 2.80; 95% CI, 1.45-5.38), and self-reporting of current sexually transmitted infection symptoms (AOR, 2.38; 95% CI, 1.61-3.52) were significant correlates of visible anogenital warts, whereas syphilis infection, transactional sex, receptive anal intercourse, and self-identifying as a transwoman were not.

CONCLUSIONS

Although not associated with key risk factors for HIV infection in Peruvian MSM and transwomen, the presence of visible anogenital warts should prompt clinicians to consider the possibility of unreported same-sex sexual behaviors and other risk sexually transmitted infection/HIV risk factors.

Accumulation of invariant NKT cells with increased IFN-γ production in persistent high-risk HPV-infected high-grade cervical intraepithelial neoplasia

BACKGROUND

Persistent high-risk human papillomavirus (HR-HPV) infection has been implicated in the development of high-grade cervical intraepithelial neoplasia (CIN) and cervical cancer. Invariant natural killer T (iNKT) cells produce large amounts of cytokines to regulate immune responses. However, the role of iNKT cells in human persistent HPV-infected cervical tissues is unknown.

METHODS

In our study, 201 patients with diagnoses ranging from normal ectocervical tissue to CINIII from June 2010 to May 2012 were enrolled. HPV DNA and HPV types were detected using the hybrid capture-2 HPV DNA test. Flow cytometry was used to investigate iNKT and CD3+ T cell infiltration into cervical tissues. Real-time quantitative reverse transcription-polymerase chain reaction was used to study IFN-γ expression and immunohistochemistry was used to determine CD3+ T cell distribution.

RESULTS

A significant increase in iNKT cells was observed in HPV-positive cervical tissues (p < 0.05), especially in CINII-III (p < 0.01). IFN-γ expression was also increased in HPV-positive cervical tissues (p < 0.05). CD3+ T cells were detected among both epithelium and stromal layers in cervical tissues, and the percentage of CD3+ T cells in HPV-positive cervical tissues was similar to that in HPV-negative cervical tissues (p > 0.05).

CONCLUSIONS

The iNKT cell aggregation in cervical tissues during the progression from HPV infection to CIN indicates that iNKT cells might play an important role in suppressing immunity. IFN-γ expression could also be related to the HPV infection status. Preventing the accumulation or functioning of iNKT cells in cervical tissues may be a viable method to prevent the development of CIN.

VIRTUAL SLIDES

The virtual slides for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/2521874671514142.

Interleukin-17A Promotes Arginase-1 Production and 2,4-Dinitrochlorobenzene-Induced Acute Hyperinflammation in Human Papillomavirus E7 Oncoprotein-Expressing Skin

Human papillomaviruses (HPVs) have evoked numerous mechanisms to subvert host innate immunity and establish a local immunosuppressive environment to facilitate persistent virus infection. Topical application of 2,4-dinitrochlorobenzene (DNCB) was speculated to overcome this immunosuppressive environment and was employed in the immunotherapy of HPV-associated lesions. We have previously shown that DNCB treatment of skin expressing HPV16.E7 protein, the major oncogenic protein expressed in HPV-associated premalignant cervical epithelium, results in a hyperinflammatory response, with an associated induction of Th2 cytokines and infiltration of myeloid cells producing arginase-1, which also contributes to the hyperinflammation. However, the molecular mechanisms underlying arginase-1 induction and arginase-mediated hyperinflammation in K14.E7 skin have not been elucidated. Here, we show that HPV16.E7 protein expression as a transgene in skin is associated with enhanced IL-17A production by macrophages exposed to DNCB. Interestingly, induction of arginase-1 by DNCB is not seen in K14.E7 animals unable to express IL-17A. Further, blockade of either IL-17A or arginase activity alleviates DNCB-induced hyperinflammation through reduced recruitment of neutrophils, as a consequence of decreased CXCL1 and CXCL5 chemokine production. Thus, our findings suggest that increased IL-17A expression by macrophages in E7-expressing skin exposed to DNCB promotes arginase-1 induction and contributes directly to the observed hyperinflammation.

Squamous cell carcinoma of the skin: epidemiology, classification, management, and novel trends

Squamous cell carcinoma (SCC) is the second most common non-melanoma skin cancer. It originates from epidermal keratinocytes or adnexal structures (such as eccrine glands or pilosebaceous units). We describe the salient features of cutaneous SCC. We also review novel classification schemes proposed during the last decade which attempt to stratify SCC lesions based on prognosis. Biopsy leads to definitive diagnosis. Treatment includes surgical excision; Mohs micrographic surgery produces excellent cure rates and spares the maximal amount of tissue. Other modalities include electrodessication and curettage, cryosurgery, radiotherapy, topical medications, photodynamic therapy, and systemic therapy. Management and follow-up depend on the risk stratification of individual lesions.

Role of IL-10 and TGF-β1 in local immunosuppression in HPV-associated cervical neoplasia

Cervical cancer is a worldwide disease that constitutes a significant public health problem, especially in developing countries, not only due to its high incidence but also because the most affected population comprises women who belong to marginalized socio-economic classes. Clinical and molecular research has identified immunological impairment in squamous intraepithelial cervical lesions and cervical cancer patients. Human Papillomavirus (HPV) has several mechanisms for avoiding the immune system: it down-regulates the expression of interferon and upregulates interleukin (IL)-10 and transforming growth factor (TGF)-β1 to produce a local immunosuppressive environment, which, along with altered tumor surface antigens, forms an immunosuppressive network that inhibits the antitumor immune response. In this review we analyzed the available data on several deregulated cellular immune functions in patients with NIC I, NIC II and NIC III and cervical cancer. The effects of immunosuppressive cytokines on innate immune response, T-cell activation and cellular factors that promote tumor cell proliferation in cervical cancer patients are summarized. We discuss the functional consequences of HPV E2, E6, and E7 protein interactions with IL-10 and TGF-β1 promoters in the induction of these cytokines and postulate its effect on the cellular immune response in squamous intraepithelial cervical lesions and cervical cancer patients. This review provides a comprehensive picture of the immunological functions of IL-10 and TGF-β1 in response to HPV in humans.

IL-17 suppresses immune effector functions in human papillomavirus-associated epithelial hyperplasia

Persistent infection with high-risk human papillomaviruses (HPV) causes epithelial hyperplasia that can progress to cancer and is thought to depend on immunosuppressive mechanisms that prevent viral clearance by the host. IL-17 is a cytokine with diverse functions in host defense and in the pathology of autoimmune disorders, chronic inflammatory diseases, and cancer. We analyzed biopsies from patients with HPV-associated cervical intraepithelial neoplasia grade 2/3 and murine skin displaying HPV16 E7 protein-induced epithelial hyperplasia, which closely models hyperplasia in chronic HPV lesions. Expression of IL-17 and IL-23, a major inducer of IL-17, was elevated in both human HPV-infected and murine E7-expressing lesions. Using a skin-grafting model, we demonstrated that IL-17 in HPV16 E7 transgenic skin grafts inhibited effective host immune responses against the graft. IL-17 was produced by CD3(+) T cells, predominantly CD4(+) T cells in human, and CD4(+) and γδ T cells in mouse hyperplastic lesions. IL-23 and IL-1β, but not IL-18, induced IL-17 production in E7 transgenic skin. Together, these findings demonstrate an immunosuppressive role for IL-17 in HPV-associated epithelial hyperplasia and suggest that blocking IL-17 in persistent viral infection may promote antiviral immunity and prevent progression to cancer.

Role of human papillomavirus in oropharyngeal squamous cell carcinoma: A review

Human papillomavirus (HPV) has been implicated in the pathogenesis of a subset of oropharyngeal squamous cell carcinoma. As a result, traditional paradigms in relation to the management of head and neck squamous cell carcinoma have been changing. Research into HPV-related oropharyngeal squamous cell carcinoma is rapidly expanding, however many molecular pathological and clinical aspects of the role of HPV remain uncertain and are the subject of ongoing investigation. A detailed search of the literature pertaining to HPV-related oropharyngeal squamous cell carcinoma was performed and information on the topic was gathered. In this article, we present an extensive review of the current literature on the role of HPV in oropharyngeal squamous cell carcinoma, particularly in relation to epidemiology, risk factors, carcinogenesis, biomarkers and clinical implications. HPV has been established as a causative agent in oropharyngeal squamous cell carcinoma and biologically active HPV can act as a prognosticator with better overall survival than HPV-negative tumours. A distinct group of younger patients with limited tobacco and alcohol exposure have emerged as characteristic of this HPV-related subset of squamous cell carcinoma of the head and neck. However, the exact molecular mechanisms of carcinogenesis are not completely understood and further studies are needed to assist development of optimal prevention and treatment modalities.

Human papillomavirus e7 oncoprotein transgenic skin develops an enhanced inflammatory response to 2,4-dinitrochlorobenzene by an arginase-1-dependent mechanism

We have shown that the expression of human papillomavirus type 16 E7 (HPV16.E7) protein within epithelial cells results in local immune suppression and a weak and ineffective immune response to E7 similar to that occuring in HPV-associated premalignancy and cancers. However, a robust acute inflammatory stimulus can overcome this to enable immune elimination of HPV16.E7-transformed epithelial cells. 2,4-Dinitrochlorobenzene (DNCB) can elicit acute inflammation and it has been shown to initiate the regression of HPV-associated genital warts. Although the clinical use of DNCB is discouraged owing to its mutagenic potential, understanding how DNCB-induced acute inflammation alters local HPV16.E7-mediated immune suppression might lead to better treatments. Here, we show that topical DNCB application to skin expressing HPV16.E7 as a transgene induces a hyperinflammatory response, which is not seen in nontransgenic control animals. The E7-associated inflammatory response is characterized by enhanced expression of Th2 cytokines and increased infiltration of CD11b(+)Gr1(int)F4/80(+)Ly6C(hi)Ly6G(low) myeloid cells, producing arginase-1. Inhibition of arginase with an arginase-specific inhibitor, N(omega)-hydroxy-nor-L-arginine, ameliorates the DNCB-induced inflammatory response. Our results demonstrate that HPV16.E7 protein enhances DNCB-associated production of arginase-1 by myeloid cells and consequent inflammatory cellular infiltration of skin.

Indoleamine 2,3-dioxygenase activity contributes to local immune suppression in the skin expressing human papillomavirus oncoprotein e7

Chronic infection of anogenital epithelium with human papillomavirus (HPV) promotes development of cancer. Many pathogens evoke immunosuppressive mechanisms to enable persistent infection. We have previously shown that grafted skin expressing HPV16 E7 oncoprotein from a keratin-14 promoter (K14E7) is not rejected by a syngeneic, immunocompetent host. In this study we show that indoleamine 2,3-dioxygenase (IDO) 1, an IFN-γ-inducible immunoregulatory molecule, is more highly expressed by langerin(-ve) dermal dendritic cells (DCs) from K14E7 skin than nontransgenic control skin. Furthermore, inhibiting IDO activity using 1-methyl-dl-tryptophan (1-D/L-MT) promotes K14E7 skin graft rejection. Increased IDO1 expression and activity in K14E7 skin requires IFN-γ and invariant natural killer T (iNKT) cells, both of which have been shown to negatively regulate T-cell effector function and suppress K14E7 graft rejection. Furthermore, DCs from K14E7 skin express higher levels of IFN-γ receptor (IFN-γR) than DCs from control skin. K14E7 transgenic skin recruits significantly higher numbers of DCs, independent of IFN-γ and IFN-γR expression. Consistent with these observations in a murine model, we found higher expression of IDO1 and IFN-γ but not IDO2 in the cervical epithelium of patients with HPV-associated cervical intraepithelial neoplasia (CIN) 2/3. Our data support a hypothesis that induction of IDO1 in HPV-infected skin contributes to evasion of host immunity.

Human papillomavirus 16-encoded E7 protein inhibits IFN-γ-mediated MHC class I antigen presentation and CTL-induced lysis by blocking IRF-1 expression in mouse keratinocytes

Human papillomavirus 16 (HPV16) infection causes 50 % or more of cervical cancers in women. The HPV16 E7 oncogene is continuously expressed in infected epithelium with its oncogenicity linked to cervical cancer. The E7 protein is an ideal target in control of HPV infection through T-cell-mediated immunity. Using HPV16 E7-transgenic mouse keratinocytes (KCs-E7) to investigate T-cell-mediated immune responses, we have shown previously that HPV16-encoded E7 protein inhibits IFN-γ-mediated enhancement of MHC class I antigen processing and T-cell-induced target cell lysis. In this study, we found that HPV16 E7 suppresses IFN-γ-induced phosphorylation of STAT1((Tyr701)), leading to the blockade of interferon regulatory factor-1 (IRF-1) and transporter associated antigen processing subunit 1 (TAP-1) expression in KCs-E7. The results of a (51)Cr release assay demonstrated that IFN-γ-treated KCs-E7 escaped from CTL recognition because HPV16 E7 downregulated MHC class I antigen presentation on KCs. Restoration of IRF-1 expression in KCs-E7 overcame the inhibitory effect of E7 protein on IFN-γ-mediated CTL lysis and MHC class I antigen presentation on KCs. Our results suggest that HPV16 E7 interferes with the IFN-γ-mediated JAK1/JAK2/STAT1/IRF-1 signal transduction pathway and reduces the efficiency of peptide loading and MHC class I antigen presentation on KCs-E7. These results may reveal a new mechanism whereby HPV16 escapes from immune surveillance in vivo.

Virus induced inflammation and cancer development

Chronic inflammation as a result of viral infection significantly increases the likelihood of cancer development. A handful of diverse viruses have confirmed roles in cancer development and progression, but the list of suspected oncogenic viruses is continually growing. Viruses induce cancer directly and indirectly, by activating inflammatory signalling pathways and cytokines, stimulating growth of infected cells and inhibiting apoptosis. Although oncogenic viruses induce inflammation by various mechanisms, it is generally mediated by the MAPK, NFκB and STAT3 signalling pathways. This review will explore the unique mechanisms by which different oncogenic viruses induce inflammation to promote cancer initiation and progression.

Post-translational control of IL-1β via the human papillomavirus type 16 E6 oncoprotein: a novel mechanism of innate immune escape mediated by the E3-ubiquitin ligase E6-AP and p53

Infections with high-risk human papillomaviruses (HPVs) are causally involved in the development of anogenital cancer. HPVs apparently evade the innate immune response of their host cells by dysregulating immunomodulatory factors such as cytokines and chemokines, thereby creating a microenvironment that favors malignancy. One central key player in the immune surveillance interactome is interleukin-1 beta (IL-1β) which not only mediates inflammation, but also links innate and adaptive immunity. Because of its pleiotropic physiological effects, IL-1β production is tightly controlled on transcriptional, post-translational and secretory levels. Here, we describe a novel mechanism how the high-risk HPV16 E6 oncoprotein abrogates IL-1β processing and secretion in a NALP3 inflammasome-independent manner. We analyzed IL-1β regulation in immortalized keratinocytes that harbor the HPV16 E6 and/or E7 oncogenes as well as HPV-positive cervical tumor cells. While in primary and in E7-immortalized human keratinocytes the secretion of IL-1β was highly inducible upon inflammasome activation, E6-positive cells did not respond. Western blot analyses revealed a strong reduction of basal intracellular levels of pro-IL-1β that was independent of dysregulation of the NALP3 inflammasome, autophagy or lysosomal activity. Instead, we demonstrate that pro-IL-1β is degraded in a proteasome-dependent manner in E6-positive cells which is mediated via the ubiquitin ligase E6-AP and p53. Conversely, in E6- and E6/E7-immortalized cells pro-IL-1β levels were restored by siRNA knock-down of E6-AP and simultaneous recovery of functional p53. In the context of HPV-induced carcinogenesis, these data suggest a novel post-translational mechanism of pro-IL-1β regulation which ultimately inhibits the secretion of IL-1β in virus-infected keratinocytes. The clinical relevance of our results was further confirmed in HPV-positive tissue samples, where a gradual decrease of IL-1β towards cervical cancer could be discerned. Hence, attenuation of IL-1β by the HPV16 E6 oncoprotein in immortalized cells is apparently a crucial step in viral immune evasion and initiation of malignancy.

Persistently high-risk HPV-infected individuals have an increased risk to develop anogenital cancer. HPV encodes the viral proteins E6 and E7 that interact with and induce the degradation of the cell cycle regulators p53 and pRb, respectively, priming immortalized keratinocytes towards malignant transformation. In early antiviral immune response, IL-1β is an important factor for the initiation of inflammation and activation of immune cells such as macrophages and T cells. Our study describes a post-translationally controlled pathway where E6 mediates proteasomal degradation of IL-1β in HPV16-immortalized human keratinocytes. This process depends on the cellular ubiquitin ligase E6-AP and p53 highlighting a novel molecular mechanism of a virus-host interaction that is critical for evading innate immune defense. IL-1β dysregulation is also found in tissue sections which represent different stages of virus-induced carcinogenesis, underlining the clinical relevance of our findings.

Human papillomavirus infections: warts or cancer?

Human papillomaviruses (HPVs) are prevalent pathogens of mucosal and cutaneous epithelia. Productive infections of squamous epithelia lead to benign hyperproliferative warts, condylomata, or papillomas. Persistent infections of the anogenital mucosa by high-risk HPV genotypes 16 and 18 and closely related types can infrequently progress to high-grade intraepithelial neoplasias, carcinomas-in-situ, and invasive cancers in women and men. HPV-16 is also associated with a fraction of head and neck cancers. We discuss the interactions of the mucosotropic HPVs with the host regulatory proteins and pathways that lead to benign coexistence and enable HPV DNA amplification or, alternatively, to cancers that no longer support viral production.

Cervical cytokines and clearance of incident human papillomavirus infection: Hawaii HPV cohort study

Mechanisms for the control and resolution of human papillomavirus (HPV) infection of the cervix include the local production of cytokines, which control recruitment and function of cells integral to pathogen control. We established a cohort of women for long-term follow-up to examine the mucosal expression of antiviral (IFN-α2), Type-1 (IFN-γ, IL-12), regulatory (IL-10), and proinflammatory (IL-1α, IL-1β, IL-6, IL-8, MIP-1α, and TNF) cytokines in association with the clearance of incident cervical HPV infection. Interviews and specimens for HPV DNA analysis and cytokine protein measurement were obtained at baseline and at 4-month intervals. A Cox proportional hazards model was used to study the relationship between clearance of 107 high-risk and 111 low-risk incident HPV infections and cytokine levels among 154 women. Positive changes from baseline levels of IL-10, IL-12, MIP-1α, and TNF were associated with significantly longer times to type-specific HPV clearance. Inverse trends in the hazard ratios associated with clearance of high-risk HPV infections were monotonic and significant for IL-12 (ptrend  = 0.02) and TNF (ptrend  = 0.02); the likelihood of high-risk HPV clearance was reduced by 65% and 67%, respectively, among women in the highest as compared with the lowest quartile of change from baseline. Our results suggest that in women with a nontransient cervical HPV infection, proinflammatory, Type-1, and regulatory cytokines are elevated, underscoring the long-term commitment of local immune mediators to viral eradication.

Treatment failure in patients with HPV 16-induced vulvar intraepithelial neoplasia: understanding different clinical responses to immunotherapy

Failure of the immune system to launch a strong and effective immune response to high-risk HPV is related to viral persistence and the development of anogenital (pre)malignant lesions such as vulvar intraepithelial neoplasia (VIN). Different forms of immunotherapy, aimed at overcoming the inertia of the immune system, have been developed and met with clinical success. Unfortunately these, in principal successful, therapeutic approaches also fail to induce clinical responses in a substantial number of cases. In this review, the authors summarize the traits of the immune response to HPV in healthy individuals and in patients with HPV-induced neoplasia. The potential mechanisms involved in the escape of HPV-induced lesions from the immune system indicate gaps in our knowledge. Finally, the interaction between the immune system and VIN is discussed with a special focus on the different forms of immunotherapy applied to treat VIN and the potential causes of therapy failure. The authors conclude that there are a number of pre-existing conditions that determine the patients' responsiveness to immunotherapy. An immunotherapeutic strategy in which different aspects of immune failure are attacked by complementary approaches, will improve the clinical response rate.

Cutaneous squamous cell carcinoma and human papillomavirus: is there an association?

BACKGROUND

The role of human papillomavirus (HPV) in the induction and maintenance of cervical, anogenital, and some oropharyngeal carcinomas is well recognized, but its role in cutaneous squamous cell carcinoma (SCC) remains to be elucidated. HPV is thought to act as a possible cocarcinogen in the development of SCC.

OBJECTIVE

To review the literature assessing the correlation between and possible causation of HPV and cutaneous SCC in immunocompetent and immunocompromised populations.

METHODS

We reviewed HPV sampling and detection methods, epidemiologic studies examining HPV carriage in immunocompetent and immunosuppressed individuals, and evidence asserting an association between HPV and cutaneous SCC.

RESULTS

Although an abundant body of evidence points toward a link between HPV and cutaneous SCC, many studies indicate otherwise. Recent studies have focused on viral activity in addition to DNA presence.

CONCLUSION

The possibility exists that HPV may play a role in the induction but not maintenance of cutaneous SCC.

Treatment of metastatic cervical cancer: future directions involving targeted agents

Cervical cancer is the third most common cause of female cancer mortality, and it remains a major health problem in populations with limited economic resources. Metastatic disease or recurrent lesions not amenable to radical local excision or regional radiation have a poor prognosis, and are treated with palliative platinum-based chemotherapy. There are few effective therapeutic options for patients who progressed after first-line chemotherapy. Future advances in the treatment of metastatic or recurrent disease may rely on more effective and better-tolerated therapies, and molecularly driven targeted agents could represent an attractive option. Inhibition of tumor angiogenesis and epidermal growth factor receptor directed therapies have focused the most recent clinical research efforts. A thorough molecular characterization of cervical cancer remains crucial for a rationale implementation of targeted agents and companion biomarkers. Alternative clinical trial designs may also be necessary to optimize the clinical development of new drugs for metastatic cervical cancer.

Human papillomavirus immunogen that provides protective tumor immunity and induces tumor regression

Human papillomavirus (HPV) is associated with premalignant lesions such as high-grade cervical intraepithelial neoplasia (CIN-III) with potential progression to cervical carcinoma. There are now preventive vaccines against HPV. However, no effective therapeutic vaccine or immunological treatment exists for individuals already infected or for the 470,000 women that develop high-grade dysplasia, carcinoma in situ, and cervical cancer each year. More than half of these women die from cervical cancer. Relative non-immunogenicity of HPV infection is one of the main reasons for the difficulty in designing a comprehensive therapeutic vaccine against HPV-induced premalignant lesions and cervical carcinoma. HPV E6 and E7 proteins, the major HPV oncogenes, are highly immunogenic but fail to induce cross-reactive and protective immune responses against heterologous strains. We designed and synthesized a therapeutic peptide vaccine comprised of multivalent peptide mixtures called hypervariable epitope constructs (HECs) that represent the major epitope variants of the oncogenic E7 structural protein, and assessed their immunogenicity and in vivo efficacy in mice. Our results show that this peptide vaccine can induce strong, HPV-specific, T-helper cell and CTL responses. More significantly, we have demonstrated that the vaccine is efficacious as a therapeutic agent in a mouse HPV tumor model. Therefore, the HPV HEC vaccine approach described herein can potentially prevent progression of HPV-associated premalignant lesions, and may also be therapeutic against tumors associated with HPV.

A randomized trial of immunotherapy for persistent genital warts

AIM

To determine whether immunotherapy with HPV6 L1 virus like particles (VLPs) without adjuvant (VLP immunotherapy) reduces recurrence of genital warts following destructive therapy.

TRIAL DESIGN

A randomized placebo controlled blinded study of treatment of recurrent genital warts amenable to destructive therapy, conducted independently in Australia and China.

METHODS

Patients received conventional destructive therapy of all evident warts together with intramuscular administration of 1 µg, 5 µg or 25 µg of VLP immunotherapy, or of placebo immunotherapy (0.9% NaCl), as immunotherapy at week 0 and week 4. Primary outcome, assessed at week 8, was recurrence of visible warts.

RESULTS

Of 33 protocol compliant Brisbane recipients of placebo immunotherapy, 11 were disease free at two months, and a further 9 demonstrated reduction of > 50% in total wart area. Wart area reduction following destructive treatment correlated with prior duration of disease. Among 102 protocol compliant Brisbane recipients of VLP immunotherapy, disease reduction was significantly greater than among the placebo immunotherapy (50% ± s.e.m. 7%) recipients for subjects receiving 5 µg or 25 µg of VLP immunotherapy/dose (71% ± s.e.m. 7%) but not for those receiving 1 µg VLP immunotherapy/dose (42% ± 7%). Of 52 protocol compliant placebo immunotherapy recipients in Wenzhou, 37 were disease free at two months, and a further 8 had > 50% disease reduction. Prior disease duration was much shorter in Wenzhou subject (8.1 ± 1.1 mo) than in Brisbane subjects (53.7 ± 5.5 mo). No significant reduction in mean wart area was observed for the 168 Wenzhou protocol compliant subjects who also received VLP immunotherapy.

CONCLUSIONS

This study confirms the findings in a previous open label trial that administration of VLP immunotherapy may assist in clearance of recurrent genital warts in patients for whom destructive therapy is unsuccessful and that unsuccessful destructive therapy is more common with increasing prior disease duration.

The epidemiology and natural history of anal human papillomavirus infection in men who have sex with men

Studies on the epidemiology and natural history of anal human papillomavirus (HPV) infection are essential to understand the significance of this virus in the aetiology of anal cancer in men who have sex with men (MSM). This paper presents a review of studies on anal HPV in MSM. For this review, a Medline search was performed to identify English-language articles published in peer-reviewed journals on the epidemiology, natural history and risk factors for anal HPV infection in MSM. Anal HPV prevalence is high in MSM and infection with multiple HPV types is common. The available prospective data suggest detection of new anal HPV infections may also be common. However, with limited epidemiological data available on infection dynamics and associated behavioural risk factors, it is difficult to draw conclusions on how persistent anal HPV infection is in this population.

Direct identification of an HPV-16 tumor antigen from cervical cancer biopsy specimens

Persistent infection with high-risk human papilloma viruses (HPV) is the worldwide cause of many cancers, including cervical, anal, vulval, vaginal, penile, and oropharyngeal. Since T cells naturally eliminate the majority of chronic HPV infections by recognizing epitopes displayed on virally altered epithelium, we exploited Poisson detection mass spectrometry (MS³) to identify those epitopes and inform future T cell-based vaccine design. Nine cervical cancer biopsies from HPV-16 positive HLA-A^*02 patients were obtained, histopathology determined, and E7 oncogene PCR-amplified from tumor DNA and sequenced. Conservation of E7 oncogene coding segments was found in all tumors. MS³ analysis of HLA-A^*02 immunoprecipitates detected E7_11–19 peptide (YMLDLQPET) in seven of the nine tumor biopsies. The remaining two samples were E7_11–19 negative and lacked the HLA-A^*02 binding GILT thioreductase peptide despite possessing binding-competent HLA-A^*02 alleles. Thus, the conserved E7_11–19 peptide is a dominant HLA-A^*02 binding tumor antigen in HPV-16 transformed cervical squamous and adenocarcinomas. Findings that a minority of HLA-A^*02:01 tumors lack expression of both E7_11–19 and a peptide from a thioreductase important in processing of cysteine-rich proteins like E7 underscore the value of physical detection, define a potential additional tumor escape mechanism and have implications for therapeutic cancer vaccine development.

A novel, broad spectrum therapeutic HPV vaccine targeting the E7 proteins of HPV16, 18, 31, 45 and 52 that elicits potent E7-specific CD8T cell immunity and regression of large, established, E7-expressing TC-1 tumors

Persistent infection by high risk genotypes of human papillomavirus (HPV) is the cause of cervical cancer, which remains one of the most common cancers among women worldwide. In addition, there is a growing appreciation that high risk HPVs are associated with a number of other cancers including anogenital cancers as well as a subset of head and neck cancers. Recently, prophylactic HPV vaccines targeting the two most prevalent high risk HPVs (HPV16 and HPV18) have been deployed in large-scale vaccination campaigns. However, the extent to which these prophylactic vaccines confer protection against other high risk HPV genotypes is largely unknown and prophylactic vaccines have been shown to be ineffective against pre-existing infection. Thus there continues to be an urgent need for effective therapeutic vaccines against HPV. The E7 protein of HPV16 has been widely studied as a target for therapeutic vaccines in HPV-associated cancer settings because HPV16 is the most prevalent of the high risk HPV genotypes. However, HPV16 accounts for only about 50% of cervical cancers and there are at least 15 other high risk HPVs that are known to be oncogenic. We have developed a novel, broad-spectrum, therapeutic vaccine (Pentarix) directed at the E7 proteins from five of the most prevalent high-risk genotypes of HPV worldwide (HPV16, 18, 31, 45 and 52) that together account for more than 80% of all HPV-associated cancers. Pentarix is a recombinant protein-based vaccine that elicits strong, multi-genotype specific CD8 T cell immunity when administered to mice in combination with adjuvants comprised of agonists of the TLR3 or TLR9 family of innate immune receptors. Furthermore, large, established E7-expressing TC-1 tumors undergo rapid and complete regression after therapeutic vaccination of mice with Pentarix. Together, these data suggest that Pentarix may be of clinical value for patients with E7-positive, HPV-associated precancerous lesions or malignant disease.

NKT cells inhibit antigen-specific effector CD8 T cell induction to skin viral proteins

We recently demonstrated that CD1d-restricted NKT cells resident in skin can inhibit CD8 T cell-mediated graft rejection of human papillomavirus E7-expressing skin through an IFN-γ-dependent mechanism. In this study, we examined the role of systemically derived NKT cells in regulating the rejection of skin grafts expressing viral proteins. In lymph nodes draining transplanted skin, Ag-specific CD8 T cell proliferation, cytokine production, and cytotoxic activity were impaired by NKT cells. NKT cell suppression was mediated via CD11c(+) dendritic cells. Inhibition of CD8 T cell function did not require Foxp3(+) regulatory T cells or NKT cell-secreted IFN-γ, IL-10, or IL-17. Thus, following skin grafting or immunization with human papillomavirus-E7 oncoprotein, NKT cells reduce the capacity of draining lymph node-resident APCs to cross-present Ag to CD8 T cell precursors, as evidenced by impaired expansion and differentiation to Ag-specific CD8 T effector cells. Therefore, in the context of viral Ag challenge in the skin, systemic NKT cells limit the capacity for effective priming of adaptive immunity.