Immune control of human papillomavirus (HPV) associated anogenital disease and potential for vaccination

ErbB2/HER2 receptor tyrosine kinase regulates human papillomavirus promoter activity

Human papillomaviruses (HPVs) are a major cause of cancer. While surgical intervention remains effective for a majority of HPV-caused cancers, the urgent need for medical treatments targeting HPV-infected cells persists. The pivotal early genes E6 and E7, which are under the control of the viral genome's long control region (LCR), play a crucial role in infection and HPV-induced oncogenesis, as well as immune evasion. In this study, proteomic analysis of endosomes uncovered the co-internalization of ErbB2 receptor tyrosine kinase, also called HER2/neu, with HPV16 particles from the plasma membrane. Although ErbB2 overexpression has been associated with cervical cancer, its influence on HPV infection stages was previously unknown. Therefore, we investigated the role of ErbB2 in HPV infection, focusing on HPV16. Through siRNA-mediated knockdown and pharmacological inhibition studies, we found that HPV16 entry is independent of ErbB2. Instead, our signal transduction and promoter assays unveiled a concentration- and activation-dependent regulatory role of ErbB2 on the HPV16 LCR by supporting viral promoter activity. We also found that ErbB2's nuclear localization signal was not essential for LCR activity, but rather the cellular ErbB2 protein level and activation status that were inhibited by tucatinib and CP-724714. These ErbB2-specific tyrosine kinase inhibitors as well as ErbB2 depletion significantly influenced the downstream Akt and ERK signaling pathways and LCR activity. Experiments encompassing low-risk HPV11 and high-risk HPV18 LCRs uncovered, beyond HPV16, the importance of ErbB2 in the general regulation of the HPV early promoter. Expanding our investigation to directly assess the impact of ErbB2 on viral gene expression, quantitative analysis of E6 and E7 transcript levels in HPV16 and HPV18 transformed cell lines unveiled a noteworthy decrease in oncogene expression following ErbB2 depletion, concomitant with the downregulation of Akt and ERK signaling pathways. In light of these findings, we propose that ErbB2 holds promise as potential target for treating HPV infections and HPV-associated malignancies by silencing viral gene expression.

HPV pathogenesis, various types of vaccines, safety concern, prophylactic and therapeutic applications to control cervical cancer, and future perspective

Over 98% of cervical cancers (CC) are caused by regular infections with "high risk" genotype of the human papilloma virus (HPV). However, this is not always the causative factor. Therefore, production of HPV vaccinations represents a significant chance to minimize the risk of CC. Phase III studies for a number of preventative HPV vaccines based on L1-virus-like particle (VLPs) have just been completed and the preliminary results are very convincing. However, there are a lot of practical concerns that need to be resolved before the use of these vaccinations. These vaccines were challenged with obvious queries such as protection time, subject receiving vaccines, time of vaccination, and how to include them into ongoing screening programs. Although these vaccines were 90% effective at preventing HPV infection as these offered only modest advantages for the removal of pre-existing infections. New advancements in the creation of therapeutic vaccinations have been explored for further improvement and post-vaccination surveillance. Therapeutic vaccines attempted to boost cell-mediated immunities and these are detrimental to the infected cell as opposed to neutralizing antibodies (different from prophylactic vaccines).

HPV-mediated Cervical Cancer: A Systematic review on Immunological Basis, Molecular Biology and Immune evasion mechanisms

BACKGROUND

Human papillomavirus (HPV), one of the most frequently transmitted viruses globally, causing several malignancies including cervical cancer.

AIM

Owing to their unique pathogenicity HPV viruses can persist in the host organism for a longer duration than other virus types, to complete their lifecycle. During its association with the host, HPV causes various pathological conditions affecting the immune system by evading the host immune- mechanisms leading to the progression of various diseases, including cancer.

METHOD

To date, ~ 150 serotypes were identified, and certain high-risk HPV types are known to be associated with genital warts and cervical cancer. As of now, two prophylactic vaccines are in use for the treatment of HPV infection, however, no effective antiviral drug is available for HPV-associated disease/infections. Numerous clinical and laboratory studies are being investigated to formulate an effective and specific vaccine again HPV infections and associated diseases.

RESULT

As the immunological basis of HPV infection and associated disease progress persist indistinctly, deeper insights on immune evasion mechanism and molecular biology of disease would aid in developing an effective vaccine.

CONCLUSION

Thus this review focuses, aiming a systematic review on the immunological aspects of HPV-associated cervical cancer by uncovering immune evasion strategies adapted by HPV.

Primary HPV screening for cervical cancer: Results after two screening rounds in a regional screening program in Finland

INTRODUCTION

Since 2012, cervical cancer screening has been conducted with a primary high-risk human papillomavirus (hrHPV) test and conventional cytology triage in the city of Tampere, Finland. The women who were screened with the hrHPV test in 2012 were invited to participate in the second screening round in 2017. The aim of the present report was to compare the number of colposcopy referrals and the number of histological high-grade squamous intraepithelial lesion (HSIL)+ (cervical intraepithelial neoplasia [CIN2+]) lesions between the first and second screening rounds of women of a specific age group who were screened twice with the hrHPV test.

MATERIAL AND METHODS

The primary hrHPV test used was the RealTime hrHPV PCR assay by Abbott. Women with a positive hrHPV test and cytology triage equal to or worse than low-grade squamous intraepithelial lesion or atypical glandular cells, favor neoplasia, were directly referred to colposcopy, whereas hrHPV-positive women with a negative or equivocal cytology triage were re-screened after approximately 12-16 months. hrHPV-negative women were scheduled for re-screening after 5 years. The present report focuses on the cohort of women who were screened twice with the hrHPV test, who were 35-55 years old in 2012, and 40-60 years old in 2017.

RESULTS

In all, 8076 women were invited for HPV screening in 2012 and 8331 women were invited for the second round 5 years later, with attendance rates of 70% and 71%, respectively. Of the women who were screened in 2012, 4571 (69%) belonged to the 35- to 55-year age cohort. In 2017, 4807 (73%) of the women aged 40-60 years participated in the screening. In this cohort, 185 (4.0%) colposcopies were performed in the first screening round, compared with 139 (2.9%) in the second round, and the colposcopy rate was 29% smaller in the second round (P = .002). The number of histological HSIL+ cases was 38 (0.8%) during the first screening round and 29 (0.6%) during the second round (P = .220).

CONCLUSIONS

In the setting of routine organized cervical cancer screening, the initially high colposcopy rate associated with primary HPV screening seems to level off at the second screening round in women who were screened twice with an hrHPV test.

Comparison of the Hybrid Capture II Method with a PCR-Based Screening Method Using a Carboxyfluorescein-Labeled Primer for Detecting Human Papillomavirus in Cervicovaginal Liquid-Based Cytology

Objective: Human papillomaviruses (HPVs) are DNA viruses, of which over 120 types have been identified. The main screening methods for HPV-DNA include the hybrid capture II (HC-II) and polymerase chain reaction (PCR) assays. Liquid-based cytology (LBC) is a high-quality technique developed to improve the diagnostic reliability of traditional Papanicolaou tests (Pap tests). However, relatively few studies have compared the efficacy of PCR and HC-II assays using cervicovaginal LBC specimens. In this study, we conducted a comparative analysis with results derived from the HC-II assay to assess whether a PCR-based assay using a novel carboxyfluorescein (FAM)-labeled primer could be applied to cervicovaginal LBC specimens. Methods and Results: We analyzed 59 specimens diagnosed as atypical squamous cells of undetermined significance (ASCUS) by Pap tests. After extracting DNA from cervicovaginal LBC specimens, we performed PCR using a FAM-labeled consensus primer, and then conducted fragment analysis to confirm the results. The value of the kappa statistic measuring the agreement between the PCR and HC-II results was 0.8557, or “almost perfect agreement.” Conclusion: Our novel HPV-PCR assay can be successfully applied to cervicovaginal LBC specimens for the detection of HPV subtypes.

Could the human papillomavirus vaccine prevent recurrence of ano-genital warts?: a systematic review and meta-analysis

Human papillomavirus (HPV) is the most prevalent sexually transmitted infection worldwide and ano-genital warts (AGWs) are highly infectious. This virus is transmitted through sexual, anal, or oral contact as well as skin-to-skin contacts. Treatment for this condition has significant morbidity and it can be frustrating in certain cases. The HPV vaccination has been demonstrated as a promising strategy of secondary prevention in HPV-related diseases such as head and neck cancers, cervical diseases, and recurrent respiratory papillomatosis. Regarding AGWs, it is unclear whether vaccination can provide analogous clinical benefit. The aim of this work is to systematically review the literature regarding HPV vaccination for secondary disease prevention after treatment of AGWs. From October to December 2018, a systematic search for clinical trials was conducted in five databases: PubMed, MEDLINE, EMBASE, Cochrane, and clinicaltrials.gov using a combination of the following descriptors: 'gardasil' OR 'cervarix' OR 'nine-valent' OR '9-valent' OR 'vaccine' AND 'recurrence' OR 'relapse' AND 'hpv' OR 'papillomavirus' AND 'warts' OR 'condyloma.' Data were synthetized and entered in the Review Manager software (RevMan 5.3.5) to perform the meta-analysis. The search yielded 824 potentially relevant studies. Two studies fulfilled the eligibility criteria involving 656 participants. The meta-analysis estimated the rate of recurrence of AGWs was similar between the vaccine group and the control group. The overall effect estimate was 1.02 (0.75-1.38). This is the first meta-analysis exploring the effect of HPV vaccine in preventing the relapse of AGWs. These results suggest that HPV vaccination does not provide secondary benefit in patients with previous AGWs. However, these results cannot be generalized due to the scarce number of RCTs currently available in the literature. The outcomes from future randomized controlled trials (RCTs) are warranted to further clarify the precise effect of the vaccine.

Oral manifestations of human papillomavirus infections

Papillomaviruses are one of the oldest viruses known, dating back 330 million years. During this long evolution, human papillomaviruses (HPV) have developed into hijackers of human cellular and immune systems in which they replicate and remain silent. Systematic studies on oral HPV infections and their outcomes are still scarce. Oral HPV infections have been linked to sexual behaviour, but recent evidence supports their horizontal, mouth‐to‐mouth, transmission. Most HPV infections in infants are acquired vertically from the mother during the intrauterine period, during delivery, or later via saliva. The best‐known benign clinical manifestations of HPV infection are oral papilloma/condyloma and focal epithelial hyperplasia. Evidence is emerging which suggests that some oral HPV infections might persist. Persistent HPV infection is mandatory for HPV‐associated malignant transformation. However, progression of HPV‐induced lesions to malignancy requires additional cofactors. In the early 1980s, we provided the first evidence that a subset of oral cancers and other head and neck cancers might be causally linked to HPV infection. This review summarizes current knowledge on the virus itself, its transmission modes, as well as the full spectrum of oral HPV infections – from asymptomatic infections to benign, potentially malignant oral lesions, and squamous cell carcinoma.

Immune evasion mechanisms of human papillomavirus: An update

Human papillomavirus (HPV) is the most frequently sexually transmitted agent in the world. It can cause cervical and other anogenital malignancies, and oropharyngeal cancer. HPV has the unique ability to persist in the host's epithelium for a long time-longer than most viruses do-which is necessary to complete its replication cycle. To this end, HPV has developed a variety of immune evasion mechanisms, which unfortunately also favor the progression of the disease from infection to chronic dysplasia and eventually to cancer. This article summarizes the current knowledge about HPV immune evasion strategies. A special emphasis lies in HPV-mediated changes of the antigen processing machinery, which is generating epitopes for T cells and contributes to the detectability of infected cells.

Designing of Epitope-Focused Vaccine by Targeting E6 and E7 Conserved Protein Sequences: An Immuno-Informatics Approach in Human Papillomavirus 58 Isolates

Human papillomavirus (HPV) is a DNA virus that belongs to the papillomavirus family and is capable of infecting humans. Currently, few vaccines are available to prevent infection by HPV. However, they are not so much effective and provide little benefit to women who have already been infected with HPV. The aim of this study was to design epitope-based vaccines of HPV58 by targeting E6 and E7 proteins of HPV58. Proteomic sequences were retrieved from different isolates at different time periods and later analyzed by performing alignment of these sequences. To ensure the capacity of humoral and cell-mediated immunity, both B cell and T cell immunity were checked for the peptides. For E6 protein, the peptide sequence from 48 to 54 amino acids and one 9-m epitope ETSVHEIEL were the most potential B cell and T cell epitopes, respectively. This peptide could interact with as many as eight MHC-1 alleles and showed high population coverage up to 90.31 %. On the other hand, the peptide region for the E7 protein ranged from 27 to 33 amino acids and two 9-m epitopes QAQPATANY, SSDEDEIGL were found as the most potential B cell and T cell epitopes, respectively. The peptide sequences could interact with as many as seven MHC-1 alleles and showed population coverage up to 90.31 %. Furthermore, conservancy analysis was also performed using in silico tools and showed a conservancy of 100 % for all the selected epitopes. In addition to this, the allergenicity of the epitopes was also evaluated. Although the study requires further in vitro and in vivo screening, this epitope-focused peptide vaccine designing opens up a new skyline that holds a prospective future in HPV research.

Design of a highly effective therapeutic HPV16 E6/E7-specific DNA vaccine: optimization by different ways of sequence rearrangements (shuffling)

Persistent infection with the high-risk Human Papillomavirus type 16 (HPV 16) is the causative event for the development of cervical cancer and other malignant tumors of the anogenital tract and of the head and neck. Despite many attempts to develop therapeutic vaccines no candidate has entered late clinical trials. An interesting approach is a DNA based vaccine encompassing the nucleotide sequence of the E6 and E7 viral oncoproteins. Because both proteins are consistently expressed in HPV infected cells they represent excellent targets for immune therapy. Here we report the development of 8 DNA vaccine candidates consisting of differently rearranged HPV-16 E6 and E7 sequences within one molecule providing all naturally occurring epitopes but supposedly lacking transforming activity. The HPV sequences were fused to the J-domain and the SV40 enhancer in order to increase immune responses. We demonstrate that one out of the 8 vaccine candidates induces very strong cellular E6- and E7- specific cellular immune responses in mice and, as shown in regression experiments, efficiently controls growth of HPV 16 positive syngeneic tumors. This data demonstrates the potential of this vaccine candidate to control persistent HPV 16 infection that may lead to malignant disease. It also suggests that different sequence rearrangements influence the immunogenecity by an as yet unknown mechanism.

Tumour suppressor gene methylation and cervical cell folate concentration are determinants of high-risk human papillomavirus persistence: a nested case control study

Background

Persistent infection with one or more high-risk human papillomavirus [HR-HPV] types increases the risk of intraepithelial neoplasia and cervical cancer. A nested case–control study was conducted to investigate the importance of cervical cell folate concentration and tumour suppressor gene methylation as risk factors for HR-HPV persistence.

Methods

Cervical cell samples from 955 women with HR-HPV infection and normal, borderline or mild dyskaryosis were retrieved from the archive of a population-based screening trial. Women were classified as cases or controls, reflecting the presence or absence [respectively] of any HR-HPV infection at a follow-up clinic at least 6 months from baseline. Cervical cell folate concentration and promoter methylation of five tumour suppressor genes were measured in independent samples from cases and controls.

Results

A higher cervical cell folate concentration [P = 0.015] was an independent predictor of infection at follow-up, together with infection with HPV-16 or infection with multiple HR-HPV types. Methylation of the tumour suppressor gene DAPK was associated with a 2.64-fold [95% CI, 1.35-5.17] increased likelihood of HPV infection whilst CDH1 methylation was associated with a 0.53-fold [95% CI, 0.331-0.844] likelihood of HR-HPV infection at follow-up. When considering women with normal or abnormal cytology, the predictive effect of higher cervical cell folate was only seen in women with mild cytology [P = 0.021]; similarly the effect of DAPK methylation was seen in women with mild or borderline cytology [P < 0.05].

Conclusions

Higher cervical cell folate concentration and promoter methylation of the tumour suppressor gene, DAPK, in women with cervical cell dyskaryosis, are associated with increased risk of HR-HPV persistence.

Potential anti-HPV and related cancer agents from marine resources: an overview

Recently, the studies on the prevention and treatment of human papillomavirus (HPV) which is closely related to the cervical cancer and other genital diseases are attracting more and more attention all over the world. Marine-derived polysaccharides and other bioactive compounds have been shown to possess a variety of anti-HPV and related cancer activities. This paper will review the recent progress in research on the potential anti-HPV and related cancer agents from marine resources. In particular, it will provide an update on the anti-HPV actions of heparinoid polysaccharides and bioactive compounds present in marine organisms, as well as the therapeutic vaccines relating to marine organisms. In addition, the possible mechanisms of anti-HPV actions of marine bioactive compounds and their potential for therapeutic application will also be summarized in detail.

Human papillomavirus, high-grade intraepithelial neoplasia and killer immunoglogulin-like receptors: a Western Australian cohort study

Background

Human papillomavirus (HPV) is the causative agent in cervical cancer and HPV genotypes 16 and 18 cause the majority of these cancers. Natural killer (NK) cells destroy virally infected and tumour cells via killer immunoglobulin-like receptors (KIR) that recognize decreased MHC class I expression. These NK cells may contribute to clearance of HPV infected and/or dysplastic cells, however since KIR controls NK cell activity, KIR gene variation may determine outcome of infection.

Methods

KIR gene frequencies were compared between 147 patients with a history of high-grade cervical intraepithelial neoplasia (CIN) and a control population of 187, to determine if any KIR genes are associated with high-grade CIN. In addition a comparison was also made between cases of high grade CIN derived from 30 patients infected with HPV 16/18 and 29 patients infected with non-16/18 HPV to determine if KIR variation contributes to the disproportional carcinogenesis derived from HPV 16/18 infection.

Results

High-grade CIN was weakly associated with the absence of KIR2DL2 and KIR2DS2 (p = 0.046 and 0.049 respectively, OR 0.6; 95% CI 0.4 – 0.9) but this association was lost after correction for multi-gene statistical analysis. No difference in KIR gene frequencies was found between high-grade CIN caused by HPV 16/18 and non-16/18.

Conclusion

No strong association between KIR genes, high-grade CIN and HPV genotype was found in the Western Australian population.

The invisible enemy - how human papillomaviruses avoid recognition and clearance by the host immune system

Human papillomavirus (HPV) needs to persist in squamous epithelia for a certain amount of time to complete its reproductive cycle. Therefore, the virus has evolved multiple immune evasion strategies. The interplay of these immune evasion mechanisms with the host immune system decides whether a HPV infection is cleared or becomes persistent. Clearance of HPV-induced lesions is mediated by a cellular immune response, consisting of both cytotoxic T lymphocyte and T helper cell responses. Persistent HPV infection, on the other hand, is the single most important risk factor for the development of HPV-associated premalignant lesions and HPV-driven cancers. This article reviews the immune evasion mechanisms employed by high-risk HPVs to escape host immune recognition and attack.

Molecular Basis for Advances in Cervical Screening

Human papillomaviruses (HPVs) cause cervical lesions, which can, in some instances, progress to high-grade neoplasia and cancer. Around half a million cases of cervical cancer occur each year, with most occurring in developing countries where cervical cancer is a major cause of cancer-related death. The reduction in cervical cancer incidence in developed countries is largely attributed to the introduction of cervical screening. Cervical screening currently depends on the identification by cytology of abnormalities in cells taken from the surface of the cervix. The standard Pap test was developed >50 years ago, and despite modifications, still forms the basis of the test currently in use in most routine screening laboratories. Advances in our understanding of the molecular mechanisms that lead to the development of cervical cancer have been slow to impact on screening, despite the relatively high false-negative rates that can be associated with the conventional Pap smear. Improvements in screening strategies fall into a number of categories. Methods that improve cell presentation and attempt to eliminate artefacts/obscuring debris can be combined with image analysis systems in order to enhance diagnostic accuracy. Such approaches still rely on cytological evaluation and do not incorporate advances in our knowledge of how HPV causes cancer. By contrast, markers of virus infection or cell cycle entry, particularly those that offer some degree of prognostic significance, may be able to highlight abnormal cells more reliably than cytology, and could be combined with cytology to improve the detection rate. Our understanding of the molecular biology of HPV infection and the organization of the HPV life-cycle during cancer progression provides a rational basis for marker selection. The general assumption that persistent active infection by high-risk HPV types is the true precursor of cervical cancer provides the rationale for HPV DNA testing in conjunction with enhanced cytology, while the development of RNA-based approaches should allow active infections to be distinguished from those that are latent. The detection in superficial cells of marker combinations at the level of RNA or protein has the potential to predict disease status more precisely than the detection of markers in isolation. There is also a need for better prognostic markers if the predictive value of screening is to be improved. The potential to control infection by vaccination should reduce the incidence of HPV-associated neoplasia in the population, and this may cause a change in the way that screening is carried out. Nevertheless, the lack of a therapeutic vaccine, and the difficulties associated with eliminating infection by multiple high-risk HPV types, means that some form of screening will still be required as a preventive measure for the control of cervical cancer for the foreseeable future.

Biomarkers of oxidant load and type-specific clearance of prevalent oncogenic human papillomavirus infection: markers of immune response?

Human papillomavirus (HPV) infection is the cause of cervical cancer. Increased production of reactive oxygen species (ROS) maybe the common mechanism through which HPV-cofactors (i.e., smoking and inflammation) influence duration of infections. Biomarkers of total oxidant load may serve as cumulative measures of ROS exposure due to these cofactors. Therefore, we conducted a study evaluating the association between biomarkers of oxidant load and duration of HPV infections, early HPV natural history events. Serum samples were obtained from 444 HPV-positive women in the Ludwig-McGill Cohort Study. Anti-5-hydroxymethyl-2'-deoxyuridine autoantibody (anti-HMdU aAb) and malondialdehyde (MDA) were measured at baseline. Cox-proportional hazard models were used to estimate the probability of clearing any HPV, oncogenic HPV, non-oncogenic HPV and HPV-16 infections. Women with elevated MDA were significantly more likely to clear prevalent oncogenic HPV infections compared to those with lower MDA levels (Adjusted Hazard Ratio (AHR) = 2.7; 95%CI = 1.4-5.1). There did not appear to be an association between elevated MDA and clearance of incident oncogenic HPV infections. Similarly, women with elevated anti-HMdU aAb levels had higher rates of prevalent oncogenic HPV infection clearance (Quartile 3:AHR = 2.2; 95%CI = 1.2-4.4; Quartile 4:AHR = 2.4; 95%CI = 1.2-4.9). Higher levels of oxidant load biomarkers were associated with increased clearance of prevalent HPV infections. However, oxidant load biomarkers measured before incident infections were not associated, suggesting that the elevation of MDA and anti-HMdU aAb may reflect an ongoing effective immune response, such as increased innate immunity. More research focused on the immune responses to HPV and elevated markers of oxidant load is needed.

Expression of HLA-I, CD8, and CD4 and Their Clinical Significance in Cervical Cancer

Background

The local tissue immune status may play a role in the progression of cervical cancer. The aim of our study is to examine the expression of HLA-I, CD8 and CD4 in various cervical diseases and investigate their association with cervical cancer.

Methods

We chose the tissues of cervical cancer, cervical intraepithelial neoplasia (CIN), chronic cervicitis and peri-cancer tissues, and then detected the expression of HLA-I, CD8 and CD4 using SP immunohistochemistry. The associations of the expression of HLA-I, CD8 and CD4 with the clinicopathologic profiles of the patients were analyzed.

Results

The percentage of positive tissue staining of HLA class I antigen in cervical cancer, CIN, chronic cervicitis and peri-cancer tissues were 40%, 95%, 100.0% and 100.0%, respectively. And the percentage of CD8 in various tissues was 35%, 95%, 100% and 100.0%, respectively. The positive tissue staining percentage of CD4 in the tissues above was 45%, 80%, 100% and 100%, respectively. The percentage of positive tissue staining of HLA-I, CD8 and CD4 were significantly lower in tissues of cervical cancer when compared with other tissues (P < 0.01). No correlation between positive tissue staining of HLA-I, CD8, and CD4 and clinicopathologic profiles was observed (P > 0.05). A positive correlation was found between HLA-I and CD8 expression (Spearman’s correlation r_s = 0.913, P < 0.001).

Conclusions

The expression of HLA-I, CD8 and CD4 are down-regulated or deleted in CIN and cervical cancer, and they may play important roles in the development and progression of CIN and cervical cancer.

Treatment of vulvar intraepithelial neoplasia with topical imiquimod: seven years median follow-up of a randomized clinical trial

OBJECTIVE

Recently we reported on the efficacy of imiquimod for treating vulvar intraepithelial neoplasia (VIN) in a placebo-controlled, double-blinded randomized clinical trial (RCT). Four weeks after treatment, a complete response was observed in 35% of patients and a partial response in 46%. All complete responders remained disease-free at 12 months follow-up. In the current investigations, we assessed long-term follow-up at least 5 years after the initial RCT.

METHODS

Twenty-four of 26 imiquimod-treated patients who had participated in the initial RCT were seen for follow-up. Primary endpoint was durability of clinical response to imiquimod assessed by naked eye vulvar examination and histology. Long-term clinical response was correlated to lesion size before start of the initial RCT. Secondary endpoints were mental health, global quality of life, body image and sexual function in relation with long-term clinical response.

RESULTS

Median follow-up period was 7.2 years (range 5.6-8.3 years). VIN recurred in one of nine complete responders. Of the initial partial responders, two became disease-free after additional imiquimod treatment. In the other partial responders, VIN recurred at least once after the initial RCT. In long-term complete responders, lesion size at study entry was smaller and these patients had a significantly better global quality of life at follow-up than patients with residual disease and/or recurrence after imiquimod treatment.

CONCLUSIONS

In case of a complete response, imiquimod is effective in the long-term. Furthermore, patients with a long-term complete response had a significantly better global quality of life than patients who recurred after imiquimod treatment.

Monitoring of human papillomavirus vaccination

Persistent infection with oncogenic human papillomavirus (HPV) is a necessary causal factor in the development of cervical cancer. Moreover, HPV, predominately type 16 and to a lesser degree type 18, is linked causally to varying proportions of other anogenital cancers (vulva, vagina, penis, anus) as well as cancers elsewhere in the body (oropharynx, larynx, conjunctiva). HPV types 6 and 11 cause most of genital warts and recurrent respiratory papillomatosis. Effective prophylactic vaccines have been developed. In this review, we address briefly the immunological aspects of HPV infection and the results of HPV vaccination trials. Internationally standardized monitoring and evaluation of prophylactic HPV vaccination programmes will be essential for arriving at the most cost-effective strategies for cancer control.

Reduced acquisition and reactivation of human papillomavirus infections among older women treated with cryotherapy: results from a randomized trial in South Africa

BACKGROUND

Treatment of women for high-grade cervical cancer precursors frequently results in clearance of the associated high-risk human papillomavirus (hrHPV) infection but the role of treatment among women without hrHPV is unknown. We investigated whether cervical cryotherapy reduces newly detected hrHPV infections among HIV-positive and HIV-negative women who were hrHPV negative when treated.

METHODS

The impact of cryotherapy on newly detected hrHPV infections was examined among 612 women of known HIV serostatus, aged 35 to 65 years, who were negative for hrHPV DNA, and randomized to either undergo cryotherapy (n = 309) or not (n = 303). All women underwent repeat hrHPV DNA testing 6, 12, 24, and 36 months later.

RESULTS

Among 540 HIV-negative women, cryotherapy was associated with a significant reduction in newly detected hrHPV infections. Women in the cryotherapy group were 55% less likely to have newly detected hrHPV than women in the control group (95% CI 0.28 to 0.71). This association was independent of the influence of changes in sexual behaviors following therapy (adjusted hazards ratio (HR) = 0.49, 95% CI 0.29 to 0.81). Among 72 HIV-positive women, similar reductions were not observed (HR = 1.10, 95% CI 0.53 to 2.29).

CONCLUSIONS

Cervical cryotherapy significantly reduced newly detected hrHPV infections among HIV-negative, but not HIV-positive women. These results raise intriguing questions about immunological responses and biological mechanisms underlying the apparent prophylactic benefits of cryotherapy.

Induction of human papillomavirus oncogene-specific CD8 T-cell effector responses in the genital mucosa of vaccinated mice

Cervical cancer, the second leading cause of cancer mortality in women worldwide, results from infection with a subset of human papillomaviruses (HPV), HPV-16 being the most prevalent type. The available prophylactic vaccines are an effective strategy to prevent this cancer in the long term. However, they only target 70-80% of all cervical cancers and cannot control existing HPV infections and associated lesions. Therapeutic vaccines are thus necessary for women who cannot benefit from prophylactic vaccination. Induction of protective immune responses in the genital mucosa (GM) may be crucial for efficacy of HPV therapeutic vaccines. We report here that mice that received a single subcutaneous (s.c.) vaccination of an adjuvanted long synthetic HPV16 E7(1-98) polypeptide showed induction of 100% tumor protection against s.c. TC-1 tumors and that tumor regression was mainly provided by CD8 T cells. In vivo cytotoxic assay revealed high E7-specific cytolytic T lymphocytes activity in spleen and in genital draining lymph nodes (LN), and E7-specific CD8 T cells could be detected in GM by tetramer staining. More importantly, high-avidity E7-specific INF-gamma secreting CD8 T cells were induced not only in blood, spleen and LN but also in GM of vaccinated mice, thus providing evidence that a parenteral vaccination may be sufficient to provide regression of genital tumors. In addition, there was no correlation between the responses measured in blood with those measured in GM, highlighting the necessity and relevance to determine the immune responses in the mucosa where HPV-tumors reside.

Epidemiology, clinical manifestations, and recent advances in vaccination against human papillomavirus

In October 2009, the Advisory Committee on Immunization Practices (ACIP) approved a newly licensed vaccine, Cervarix, directed against human papillomavirus (HPV) to prevent cervical cancer. The ACIP also expanded its recommendations against HPV by giving permission to physicians to vaccinate males aged 9 to 26 years with the previously licensed vaccine, Gardasil, to prevent genital warts, in addition to its previous recommendation for females aged 9 to 26 years to prevent cervical cancer and genital warts. The marketing, expense, safety, and reactivity of Gardasil continue to be the subject of controversy. Of the >100 types of HPVs, approximately 40 are sexually transmitted, and HPV is the most common sexually transmitted disease. By age 50 years, 80% of women will have contracted a sexually transmitted HPV infection. While most individuals are clear of infection by 2 years, some types of HPV carry a high risk for progressing to cancer, and HPV is identified in >99% of patients with cervical cancer. Each year in the United States approximately 12,000 women develop cervical cancer and nearly 4000 die of it. Human papillomavirus is also associated with genital warts and other anogenital cancers. The United States has now licensed 2 vaccines against HPV, Gardasil and Cervarix. Gardasil has been shown to be safe and effective in preventing HPV infections by types 6, 11, 16, and 18; types 16 and 18 are associated with 2 high-risk types of cervical cancer and are associated with 70% of all cervical cancers. Types 6 and 11 are associated with 90% of anogenital warts. Cervarix has also been shown to be safe and effective in preventing HPV infections by types 16 and 18, but offers no known protection against anogenital warts.

Phase II trial of imiquimod and HPV therapeutic vaccination in patients with vulval intraepithelial neoplasia

BACKGROUND

Vulval intraepithelial neoplasia (VIN) is a premalignant condition, which is frequently associated with type HPV16 infection, and multifocal disease has high rates of surgical treatment failure.

METHODS

We report a phase II clinical trial of the topical immunomodulator, imiquimod, for 8 weeks, followed by 3 doses (weeks 10, 14 and 18) of therapeutic human papillomavirus (HPV) vaccination (TA-CIN, fusion protein HPV16 E6E7L2) in 19 women with VIN grades 2 and 3. Histology and HPV testing of biopsies were performed at weeks 0, 10, 20 and 52. Intralesional infiltration of T-cell subsets and lymphocyte proliferation for HPV systemic immune responses were also assessed.

RESULTS

Lesion response (complete regression of VIN on histology) was observed in 32% (6 out of 19) of women at week 10, increasing to 58% (11 out of 19) at week 20 and 63% (12 out of 19) at week 52. At this time, 36% (5 out of 14) of lesions showed HPV16 clearance and 79% (15 out of 19) of women were symptom free. At week 20, after treatment with imiquimod and vaccination, there was significantly increased local infiltration of CD8 and CD4 T cells in lesion responders; in contrast, non-responders (persistent VIN by histology) showed an increased density of T regulatory cells. After vaccination, only lesion responders had significantly increased lympho-proliferation to the HPV vaccine antigens.

CONCLUSION

The therapeutic effect of treatment depends on the differential immune response of responders and non-responders with affect locally and systemically.

Public health issues related to HPV vaccination

The human papillomavirus (HPV) is clearly established as the cause of cervical cancer, and vaccines targeting oncogenic forms of the virus are important as a primary method of prevention. However, barriers to cervical screening and vaccination such as a lack of knowledge of HPV, access to healthcare, and poor follow-up prevent the acceptance and utilization of HPV vaccines. Strategies for prevention of disease and implementation of vaccination are in development, but the importance of primary prevention of HPV infection needs to be stressed. This review assesses the potential impact of vaccination for cervical cancer, barriers to vaccination, and the methods used to increase coverage. With the advent of prophylactic vaccines, HPV, a common infection in the United States, can be prevented in most women.

Reversal of papilloma growth in rabbits therapeutically vaccinated against E6 with naked DNA and/or vesicular stomatitis virus vectors

Persistent infection with high-risk human papillomaviruses (HPVs) is the greatest risk factor for the development of HPV-associated cancers. In this study rabbits bearing persistent and potentially malignant papillomas were used to test the efficacy of vaccination with a recombinant DNA and/or vesicular stomatitis virus (VSV) targeting the cottontail rabbit papillomavirus (CRPV) E6 protein. Immune responses were primed with either vector and boosted twice with the homologous or heterologous E6 vector. Over the course of 18 weeks, E6 vaccination reduced papilloma volumes to one third the volume in the controls, and the rabbits boosted with an heterologous vector tended to mount stronger responses. Small and medium-sized papillomas responded significantly but only slightly better than large papillomas. Finally the initial papilloma burden per rabbit, ranging from <100 mm(3) to >1000 mm(3), was not prognostic of antitumor efficacy. In summary both E6 vaccines elicited significant therapeutic immunity, and their sequential use tended to be advantageous.

Serological study in Tunisian cervical cancer patients

OBJECTIVE

The aim of this study is to use a novel ELISA, based on five recombinant HPV-16 and HPV-18 proteins, for detection HPV-specific antibodies in a case-control study.

PATIENTS AND METHODS

L1, E6 and E7 genes have been over expressed in Escherichia coli as double fused proteins. These recombinant proteins were used in a GST-capture ELISA as coating antigens. Human sera were collected from women with cervical cancer. Negative human sera were collected from patients apparently healthy and may be affected by other infectious agents.

RESULTS

Most of the sera showed a positive reactivity to at least one of the HPV-16 or HPV-18 proteins (52/71). A percentage of 39.50% of the sera from HPV-16 infected women and 21.12% of the sera from women infected by HPV-18 genotype recognised at least one of the HPV-16 or HPV-18 proteins. Sera showed different reactivity to L1, E6 and E7 antigens, and only a few serum samples reacted to L1, E6 and E7 HPV-16, E6 and E7 HPV-18 (co-infection). Differences of reactivity between cases and controls were significant (P<0.0001).

CONCLUSION

This novel ELISA, based on recombinant HPV-16 and HPV-18 antigens, is able to detect antibodies in women infected by HPV genotypes. The assay is easy to perform and has low cost, making it suitable for monitoring the natural history of HPV infections as well as for detecting pre-existing HPV antibodies in women who receive vaccination.

Acquired immune response to oncogenic human papillomavirus associated with prophylactic cervical cancer vaccines

Human papillomavirus (HPV) is a common infection among women and a necessary cause of cervical cancer. Oncogenic HPV types infecting the anogenital tract have the potential to induce natural immunity, but at present we do not clearly understand the natural history of infection in humans and the mechanisms by which the virus can evade the host immune response. Natural acquired immune responses against HPV may be involved in the clearance of infection, but persistent infection with oncogenic virus types leads to the development of precancerous lesions and cancer. B cell responses are important for viral neutralization, but antibody responses in patients with cervical cancer are poor. Prophylactic vaccines targeting oncogenic virus types associated with cervical cancer have the potential to prevent up to 80% of cervical cancers by targeting HPV types 16 and 18. Clinical data show that prophylactic vaccines are effective in inducing antibody responses and in preventing persistent infection with HPV, as well as the subsequent development of high-grade cervical intraepithelial neoplasia. This article reviews the known data regarding natural immune responses to HPV and those developed by prophylactic vaccination.

Projected cost-effectiveness of new vaccines for adolescents in the United States

BACKGROUND

Economic assessments that guide policy making on immunizations are becoming increasingly important in light of new and anticipated vaccines for adolescents. However, important considerations that limit the utility of these assessments, such as the diversity of approaches used, are often overlooked and should be better understood.

OBJECTIVE

Our goal was to examine economic studies of adolescent vaccines and compare cost-effectiveness outcomes among studies on a particular vaccine, across adolescent vaccines, and between new adolescent vaccines versus vaccines that are recommended for young children.

METHODS

A systematic review of economic studies on immunizations for adolescents was conducted. Studies were identified by searching the Medline, Embase, and EconLit databases. Each study was reviewed for appropriateness of model design, baseline setup, sensitivity analyses, and input variables (ie, epidemiologic, clinical, cost, and quality-of-life impact). For comparison, the cost-effectiveness outcomes reported in key studies on vaccines for younger children were selected.

RESULTS

Vaccines for healthy adolescents were consistently found to be more costly than the health care or societal cost savings they produced and, in general, were less cost-effective than vaccines for younger children. Among the new vaccines, pertussis and human papillomavirus vaccines were more cost-effective than meningococcal vaccines. Including herd-immunity benefits in studies significantly improved the cost-effectiveness estimates for new vaccines. Differences in measurements or assumptions limited further comparisons.

CONCLUSION

Although using the new adolescent vaccines is unlikely to be cost-saving, vaccination programs will result in sizable health benefits.

2006 consensus guidelines for the management of women with cervical intraepithelial neoplasia or adenocarcinoma in situ

OBJECTIVE

To provide updated consensus guidelines for the management of women with cervical intraepithelial neoplasia (CIN) or adenocarcinoma in situ (AIS).

PARTICIPANTS

A group of 146 experts including representatives from 29 professional organizations, federal agencies, and national and international health organizations met on September 18-19, 2006, in Bethesda, MD, to develop the guidelines. MAJOR CHANGES IN THE GUIDELINES: The management of women with CIN grade 1 (CIN 1) has been modified significantly. In the earlier guidelines, management depended on whether the colposcopic examination was satisfactory and treatment using ablative or excisional methods was acceptable for women with CIN 1. In the new guidelines, cytological follow-up is the only recommended management option, regardless of whether the colposcopic examination is satisfactory, for women with CIN 1 who have a low-grade referral cervical cytology. Treatment of CIN 1 is particularly discouraged in adolescents. The basic management of women in the general population with CIN 2,3 underwent only minor modifications, but options for the conservative management of adolescents with CIN 2,3 have been expanded. Moreover, management recommendations for women with biopsy-confirmed AIS are now included.

CONCLUSION

Updated evidenced-based guidelines have been developed for the management of women with CIN or AIS. These guidelines reflect recent changes in our understanding of human papillomavirus-associated diseases of the cervix and the potential impact of treatment on future pregnancies.

Tumor-infiltrating cytotoxic T cells but not regulatory T cells predict outcome in anal squamous cell carcinoma

PURPOSE

Tumor-infiltrating lymphocytes (TIL) are a possible prognostic factor in solid tumors. Cytotoxic TILs are generally considered as prognostically favorable, whereas regulatory T cells (Treg) may have adverse effects by virtue of their ability to inhibit effector cells. We have evaluated the effect of T-cell subsets on survival in patients with anal squamous cell carcinoma following radiochemotherapy.

METHODS

Biopsy specimens from 38 patients with anal carcinomas were evaluated using tissue microarrays and immunohistochemistry for the presence of tumor-infiltrating immune cells using CD3, CD4, CD8, and CD68 antibodies. Treg were identified using an antibody directed against the transcription factor FoxP3, and granzyme B served as a marker for cytotoxic cells. Intratumoral immune cells were enumerated using a semiautomatic image analysis program. Prognostic effect of TIL subsets was evaluated by the log-rank test comparing no evidence of disease survival for groups with high and low numbers using median values as cutoff.

RESULTS

CD3+ and CD4+ TILs influenced no evidence of disease survival: 3-year rates for patients with low numbers were 89% and 95%, respectively, and 54% (P = 0.02) and 48%, (P = 0.01), respectively, in cases with high numbers. Large numbers of tumor-infiltrating granzyme B+ cytotoxic cells had a significant negative prognostic effect (P = 0.008), whereas no effect was observed for Treg.

CONCLUSIONS

TILs were identified as negative prognostic indicators in anal squamous cell carcinomas with granzyme B+ cytotoxic cells showing highest effect on outcome. This is possibly explained by the selection of therapy-resistant tumor cell clones. No prognostic influence of Treg was found. Knowledge of local immune responses is important for the development of immunotherapeutic strategies.

CD4(+)CD25hi regulatory T-cell frequency correlates with persistence of human papillomavirus type 16 and T helper cell responses in patients with cervical intraepithelial neoplasia

CD4(+)CD25(hi)CTLA4(+)FoxP3(+) regulatory T cells (Treg) have been shown to maintain immune tolerance against self antigens and increased circulating frequencies have been reported in various types of cancers. Circulating invariant natural killer T-cells (iNKT) are reduced in cancer patients and low iNKT frequency is related to poor prognosis. It is not yet clear whether high Treg numbers and low iNKT cell numbers pose an increased risk for the progression of premalignant lesions or whether Treg and iNKT cell numbers are influenced by dysplasia. We therefore studied prospectively the relation between iNKT cell and Treg frequencies and the natural course of human papillomavirus type 16 (HPV16) induced pre-malignant cervical dysplasia in 82 patients who participated in a nonintervention cohort study of women with abnormal cytology. Treg frequencies were significantly increased in women who had persistent HPV16 infection. Within the HPV16 persistence group there was no difference in Treg frequencies among patients who developed a CIN3 lesion and patients who did not progress to CIN3. Furthermore, Treg frequencies were increased in patients who had detectable HPV16 E7 specific IL-2 producing T-helper cells, which suggests a causal role of HPV infection in Treg development in parallel with HPV16 specific T helper cells. No evidence was found for a role for iNKT cells in persistence of HPV16 and progression of HPV16 induced CIN lesions. However, HPV-persistence-associated Tregs may explain the inefficacy of concomitant persistence associated immunity and may contribute to subsequent progression to neoplasia.

2006 consensus guidelines for the management of women with cervical intraepithelial neoplasia or adenocarcinoma in situ

A group of 146 experts representing 29 organizations and professional societies met Sept. 18-19, 2006, in Bethesda, MD, to develop revised evidence-based, consensus guidelines for managing women with abnormal cervical cancer screening tests. The management of low-grade cervical intraepithelial neoplasia (CIN) grade 1 has been modified significantly. Previously, management depended on whether colposcopy was satisfactory and treatment using ablative or excisional was acceptable for all women with CIN 1. In the new guidelines, cytological follow-up is the only recommended management option for women with CIN 1 who have low-grade referral cervical cytology, regardless of whether the colposcopic examination is satisfactory. Treatment is particularly discouraged in adolescents. The basic management of women in the general population with CIN 2,3 underwent only minor modifications, but options for the conservative management of adolescents with CIN 2,3 have been expanded. Moreover, management recommendations for women with biopsy-confirmed adenocarcinoma in situ are now included.

A cancer cell-specific inducer of apoptosis

Human papillomavirus (HPV) DNA is found in virtually all cervical cancers, strongly suggesting that these viruses are necessary to initiate this disease. The HPV E2 protein is required for viral replication, but E2 expression is usually lost in HPV-transformed cells because of the integration of viral DNA into the host chromosome. Several studies have shown that the reintroduction of E2 into HPV-transformed cells can induce growth arrest and apoptotic cell death. This raises the possibility that E2 could be useful in the treatment of HPV-induced disease. However, the effects of E2 on cell proliferation are not limited to HPV-transformed cells. The E2 protein from HPV type 16 can induce apoptosis via at least two pathways. One pathway involves the binding of E2 to p53 and operates in HPV-transformed cells, many non-HPV-transformed cell lines, and untransformed normal cells. The second pathway requires the binding of E2 to the viral genome and operates only in HPV-transformed cells. A mutation in E2 that significantly reduces the binding of this protein to p53 abrogates the induction of apoptosis in non-HPV-transformed cells and normal cells, but has no effect on the ability of the mutated protein to induce apoptosis in HPV-transformed cells. Here we show that a chimeric protein consisting of this mutant of E2, fused to the herpes simplex virus type 1 VP22 protein, can traffic between cells in a three-dimensional tumor model and induce apoptosis in HPV-transformed cells with high specificity. This cancer cell-specific inducer of apoptosis may be useful in the treatment of cervical cancer and other HPV-induced diseases.

Induction of CD4-independent E7-specific CD8+ memory response by heat shock fusion protein

Infection with human papillomavirus type 16 (HPV16) is strongly associated with a number of disease states, of which cervical and anal cancers represent the most drastic endpoints. Induction of T-cell-mediated immunity, particularly cytotoxic T lymphocytes (CTL), is important in eradication of HPV-induced lesions. Studies have shown that heat shock protein fusion proteins are capable of inducing potent antigen-specific CTL activity in experimental animal models. In addition, E7-expressing tumors in C57BL/6 mice can be eradicated by treatment with HspE7, an Hsp fusion protein composed of Mycobacterium bovis BCG Hsp65 linked to E7 protein of HPV16. More importantly, HspE7 has also displayed significant clinical benefit in phase II clinical trials for the immunotherapy of HPV-related diseases. To delineate the mechanisms underlying the therapeutic effects of HspE7, we investigated the capability of HspE7 to induce antigen-specific protective immunity. Here, we demonstrate that HspE7 primes potent E7-specific CD8(+) T cells with cytolytic and cytokine secretion activities. These CD8(+) T cells can differentiate into memory T cells with effector functions in the absence of CD4(+) T-cell help. The HspE7-induced memory CD8(+) T cells persist for at least 17 weeks and confer protection against E7-positive murine tumor cell challenge. These results indicate that HspE7 is a promising immunotherapeutic agent for treating HPV-related disease. Moreover, the ability of HspE7 to induce memory CD8(+) T cells in the absence of CD4(+) help indicates that HspE7 fusion protein may have activity in individuals with compromised CD4(+) functions, such as those with invasive cancer and/or human immunodeficiency virus infection.

Combined serial section-based 3D reconstruction of cervical carcinoma invasion using H&E/p16INK4a/CD3 alternate staining

BACKGROUND

Malignant growth and invasiveness of cancers is a function of both intratumoral and stromal factors. The accessibility to nutrients, oxygen and growth factors, the stromal composition, and the interference with the immune system all shape the tumor invasion front. A recent study has shown a prognostic difference with respect to different invasion patterns analyzed on histological specimens of cervical cancers. The present study analyzes the spatial organization of a cervical cancer and the relation of the tumor invasion front and the infiltration with CD3(+) T-cells.

METHODS

From a cervical squamous cell carcinoma specimen, 84 serial sections were performed and three interleaving series were stained with hematoxylin/eosin and immunohistochemistry directed against the cervical carcinoma biomarker p16(INK4a) and the T-cell marker CD3. Sections were passed through an image processing chain to obtain a reconstructed and segmented tissue volume. For local tumor invasion front analysis the mean curvature was used, which in turn was related to the respective local minimum tumor to T-cell distance as well to a T-cell originated diffusing substance's concentration at the tumor surface.

RESULTS

Spatial models of the tumor tissue and the infiltrating T-cells were computed. The overall discrete compactness of the tumor invasion front was 0.89, corresponding to a pathological assessment of diffuse infiltration. The comparison of the tumor invasion front with the density of T-cell infiltration revealed an increased smoothening in regions with high T-cell infiltration.

CONCLUSIONS

We could demonstrate the spatial organization of a cervical cancer and model the interaction between infiltrating T-cells with the tumor invasion front shape. Increased smoothening in regions with high T-cell infiltration suggests that T-cells may have an influence on the shaping of the tumor invasion front, e.g., by attacking tumor cells displaying specific antigens. The applied technique allows visualization of the spatial organization of tissues and could be extended to analyze multiple stains on alternating sections.

Translational mini-review series on vaccines: Monitoring of human papillomavirus vaccination

Persistent infection with oncogenic human papillomavirus (HPV) is a necessary cause of cervical cancer. Moreover, HPV type 16 (and to a lesser degree HPV type 18) is linked with more rare cancers, namely cancer of the vulva, vagina, penis, anus, oropharynx and larynx. Effective prophylactic vaccines have been developed. In this review, we briefly address immunological aspects of HPV infection and the results of HPV vaccination trials. Internationally standardized monitoring and evaluation of prophylactic HPV vaccination programmes will be essential for arriving at the most (cost-)effective strategies for cancer control.

Review of current knowledge on HPV vaccination: An Appendix to the European Guidelines for Quality Assurance in Cervical Cancer Screening

The recognition of a strong etiological relationship between infection with high-risk human papillomavirusses and cervical cancer has prompted research to develop and evaluate prophylactic and therapeutic vaccines. One prophylactic quadrivalent vaccine using L1 virus-like particles (VLP) of HPV 6, 11, 16 and 18 is available on the European market since the end of 2006 and it is expected that a second bivalent vaccine containing VLPs of HPV16 and HPV18 will become available in 2007. Each year, HPV16 and HPV18 cause approximately 43,000 cases of cervical cancer in the European continent. Results from the phase-IIb and III trials published thus far indicate that the L1 VLP HPV vaccine is safe and well-tolerated. It offers HPV-naive women a very high level of protection against HPV persistent infection and cervical intra-epithelial lesions associated with the types included in the vaccine. HPV vaccination should be offered to girls before onset of sexual activity. While prophylactic vaccination is likely to provide important future health gains, cervical screening will need to be continued for the whole generation of women that is already infected with the HPV types included in the vaccine. Phase IV studies are needed to demonstrate protection against cervical cancer and to verify duration of protection, occurrence of replacement by non-vaccine types and to define future policies for screening of vaccinated cohorts. The European Guidelines on Quality Assurance for Cervical Cancer Screening provides guidance for secondary prevention by detection and management of precursors lesions of the cervix. The purpose of the appendix on vaccination is to present current knowledge. Developing guidelines for future use of HPV vaccines in Europe, is the object of a new grant offered by the European Commission.

Circulating human papillomavirus type 16 specific T-cells are associated with HLA Class I expression on tumor cells, but not related to the amount of viral oncogene transcripts

Human papillomavirus (HPV) is a necessary factor in the pathogenesis of cervical cancer. Circulating HPV-specific T-cells responding to the E6 and E7 HPV proteins can be detected only in half of cervical cancer patients. Potential explanations for the absence of this response are lack of sufficient amounts of antigen to activate the immune response or local immune escape mechanisms. We studied the relationship between HPV 16 E6/E7 oncogene mRNA expression, human leukocyte antigen (HLA) expression on tumor cells and the presence of circulating E6- and E7-specific T-cell responses in cervical cancer patients. The amount of antigen was assessed by HPV E6/E7 mRNA expression levels measured by quantitative polymerase chain reaction. HLA Class I and Class II expression on tumor cells was analyzed by immunohistochemistry. A proliferative HPV-specific T-cell response was detected in 15/29 patients. The amount of HPV E6/E7 mRNA was not related to the presence of immune response. HLA Class I expression was downregulated in 19 patients and completely lost in 7 patients. HLA Class II expression was upregulated in 18 patients. HLA Class I expression on tumor cells showed a strong correlation with immunity (p = 0.001). Explicitly, all patients with complete HLA loss lacked HPV specific T-cell responses. The presence of circulating HPV-specific T-cells might reflect ongoing antitumor response that is sustained by CD8+ T-cells killing HLA Class I positive cancer cells. We hypothesize that HLA Class I expression status on tumor cells might as well influence the response to HPV E6/E7 directed immunotherapy.

Functional signatures of protective antiviral T-cell immunity in human virus infections

The most common human viruses have different abilities to establish persistent chronic infection. Virus-specific T-cell responses are critical in the control of virus replication and in the prevention of disease in chronic infection. A large number of phenotypic markers and a series of functions have been used to characterize virus-specific CD4+ and CD8+ T-cell responses, and these studies have shown great phenotypic and functional heterogeneity of the T-cell responses against different viruses. The heterogeneity of the T-cell response has been proposed to be specific to each virus. However, over the past 2 years, several studies have provided evidence that the phenotypic and functional heterogeneity of CD4+ and CD8+ T-cell responses is predominantly regulated by the levels of antigen load. The levels of antigen load modulate the phenotypic and functional patterns of the T-cell response within the same virus infection. Furthermore, the functional characterization of virus-specific CD4+ and CD8+ T-cell responses has identified signatures of protective antiviral immunity. Polyfunctional, i.e. interleukin-2 and interferon-gamma (IFN-gamma) secretion and proliferation, and not monofunctional, i.e. IFN-gamma secretion, CD4+ and CD8+ T-cell responses represent correlates of protective antiviral immunity in chronic virus infections.

Serum antibody response to Human papillomavirus (HPV) infections detected by a novel ELISA technique based on denatured recombinant HPV16 L1, L2, E4, E6 and E7 proteins

Background

Human papillomaviruses (HPVs) are the primary etiological agents of cervical cancer and are also involved in the development of other tumours (skin, head and neck). Serological survey of the HPV infections is important to better elucidate their natural history and to disclose antigen determinants useful for vaccine development. At present, the analysis of the HPV-specific antibodies has not diagnostic value for the viral infections, and new approaches are needed to correlate the antibody response to the disease outcome. The aim of this study is to develop a novel ELISA, based on five denatured recombinant HPV16 proteins, to be used for detection HPV-specific antibodies.

Methods

The HPV16 L1, L2, E4, E6 and E7 genes were cloned in a prokaryotic expression vector and expressed as histidine-tagged proteins. These proteins, in a denatured form, were used in ELISA as coating antigens. Human sera were collected from women with abnormal PAP smear enrolled during an ongoing multicenter HPV-PathogenISS study in Italy, assessing the HPV-related pathogenetic mechanisms of progression of cervical cancer precursor lesions. Negative human sera were collected from patients affected by other infectious agents. All the HPV-positive sera were also subjected to an avidity test to assess the binding strength in the antigen-antibody complexes.

Results

Most of the sera showed a positive reactivity to the denatured HPV16 proteins: 82% of the sera from HPV16 infected women and 89% of the sera from women infected by other HPV genotypes recognised at least one of the HPV16 proteins. The percentages of samples showing reactivity to L1, L2 and E7 were similar, but only a few serum samples reacted to E6 and E4. Most sera bound the antigens with medium and high avidity index, suggesting specific antigen-antibody reactions.

Conclusion

This novel ELISA, based on multiple denatured HPV16 antigens, is able to detect antibodies in women infected by HPV16 and it is not genotype-specific, as it detects antibodies also in women infected by other genital HPVs. The assay is easy to perform and has low cost, making it suitable for monitoring the natural history of HPV infections as well as for detecting pre-existing HPV antibodies in women who receive VLP-based HPV vaccination.

A circadian model for viral persistence

Persistently infecting DNA viruses depend heavily on host cell DNA synthesis machinery. Replication of cellular and viral DNA is inhibited by mutagenic stress. It is hypothesized that diurnal regulation of viral DNA replication may occur at the level of cell cycle checkpoints and DNA repair, to protect DNA from exposure to UV light or other mutagens. This highly conserved mechanism is traced back to viruses that persist in prokaryotes and eukaryotes. Inhibition of viral DNA replication and the cell cycle in response to UV light may represent a functional building block in the evolution of circadian-gated DNA replication. Viral DNA replication appears to be closely linked to the circadian clock by interaction of viral promoters, early viral proteins and transcription factors. It is proposed here that under certain conditions viral oncogene expression is phase-shifted relative to that of tumor suppressor and DNA repair genes. The resulting desynchrony of checkpoint controls and DNA repair from diurnal genotoxic exposure produces cyclic periods of suboptimal response to DNA damage. This temporal vulnerability to genotoxic stress produces a "mutator phenotype" with inherent genome instability. The proposed model delineates areas of research with implications for viral pathogenesis and therapeutics.

Novel methods to treat and prevent human papillomavirus infection

The human papillomavirus (HPV), a ubiquitous sexually transmitted virus, is the causative agent for cervical dysplasia and carcinoma worldwide. Current treatment methods primarily utilize ablative and excisional procedures to remove dysplastic, HPV-infected cervical tissue. However, these procedures require intensive cytopathological surveillance and carry inherent risks of bleeding, infection and possible future pregnancy complications. Development of an effective vaccine against HPV would dramatically reduce the need for costly cytological and histological surveillance. HPV represents an ideal candidate for vaccine development, and current research efforts in the realm of prophylactic and therapeutic vaccine design show great promise. A host of various vaccine techniques are currently being developed and tested and, if effective, will have a significant impact on the incidence of cervical dysplasia and carcinoma.

Papillomavirus and treatment

Human papillomaviruses (HPVs) are small DNA viruses responsible for a broad range of clinical presentations, characterized histologically by the proliferation of epithelial cells. HPVs are responsible for benign as well as malignant lesions, the most frequent of the latter being cervical carcinoma. A better knowledge of the immunobiology of these lesions allowed the development of prophylactic vaccines (for the most frequent genital types) that are presently under evaluation. The present paper describes different approaches for the treatment of HPV lesions, still mostly based on surgery, and underlines the importance of developing adjuvant therapies.