Cutaneous and mucosal human papillomaviruses differ in net surface charge, potential impact on tropism

HPV8-induced STAT3 activation led keratinocyte stem cell expansion in human actinic keratoses

Despite epidermal turnover, the skin is host to a complex array of microbes, including viruses, such as HPV, which must infect and manipulate skin keratinocyte stem cells (KSCs) to survive. This crosstalk between the virome and KSC populations remains largely unknown. Here, we investigated the effect of HPV8 on KSCs using various mouse models. We observed that the HPV8 early region gene E6 specifically caused Lrig1+ hair follicle junctional zone KSC proliferation and expansion, which would facilitate viral transmission. Within Lrig1+ KSCs specifically, HPV8 E6 bound intracellular p300 to phosphorylate the STAT3 transcriptional regulatory node. This induced ΔNp63 expression, resulting in KSC expansion into the overlying epidermis. HPV8 was associated with 70% of human actinic keratoses. Together, these results define the "hit-and-run" mechanism for HPV8 in human actinic keratosis as an expansion of KSCs, which lack melanosome protection and are thus susceptible to sun light-induced malignant transformation.

Comparative Analysis of Alpha and Beta HPV E6 Oncoproteins: Insights into Functional Distinctions and Divergent Mechanisms of Pathogenesis

Human papillomaviruses (HPVs) represent a diverse group of DNA viruses that infect epithelial cells of mucosal and cutaneous tissues, leading to a wide spectrum of clinical outcomes. Among various HPVs, alpha (α) and beta (β) types have garnered significant attention due to their associations with human health. α-HPVs are primarily linked to infections of the mucosa, with high-risk subtypes, such as HPV16 and HPV18, being the major etiological agents of cervical and oropharyngeal cancers. In contrast, β-HPVs are predominantly associated with cutaneous infections and are commonly found on healthy skin. However, certain β-types, notably HPV5 and HPV8, have been implicated in the development of non-melanoma skin cancers in immunocompromised individuals, highlighting their potential role in pathogenicity. In this review, we comprehensively analyze the similarities and differences between α- and β-HPV E6 oncoproteins, one of the major drivers of viral replication and cellular transformation, and how these impact viral fitness and the capacity to induce malignancy. In particular, we compare the mechanisms these oncoproteins use to modulate common cellular processes-apoptosis, DNA damage repair, cell differentiation, and the immune response-further shedding light on their shared and distinct features, which enable them to replicate at divergent locations of the human body and cause different types of cancer.

Viruses in saliva from sanctuary chimpanzees (Pan troglodytes) in Republic of Congo and Uganda

Pathogen surveillance for great ape health monitoring has typically been performed on non-invasive samples, primarily feces, in wild apes and blood in sanctuary-housed apes. However, many important primate pathogens, including known zoonoses, are shed in saliva and transmitted via oral fluids. Using metagenomic methods, we identified viruses in saliva samples from 46 wild-born, sanctuary-housed chimpanzees at two African sanctuaries in Republic of Congo and Uganda. In total, we identified 20 viruses. All but one, an unclassified CRESS DNA virus, are classified in five families: Circoviridae, Herpesviridae, Papillomaviridae, Picobirnaviridae, and Retroviridae. Overall, viral prevalence ranged from 4.2% to 87.5%. Many of these viruses are ubiquitous in primates and known to replicate in the oral cavity (simian foamy viruses, Retroviridae; a cytomegalovirus and lymphocryptovirus; Herpesviridae; and alpha and gamma papillomaviruses, Papillomaviridae). None of the viruses identified have been shown to cause disease in chimpanzees or, to our knowledge, in humans. These data suggest that the risk of zoonotic viral disease from chimpanzee oral fluids in sanctuaries may be lower than commonly assumed.

Chimeric Human Papillomavirus-16 Virus-like Particles Presenting HIV-1 P18I10 Peptide: Expression, Purification, Bio-Physical Properties and Immunogenicity in BALB/c Mice

Human papillomavirus (HPV) vaccines based on HPV L1 virus-like particles (VLPs) are already licensed but not accessible worldwide. About 38.0 million people were living with HIV in 2020 and there is no HIV vaccine yet. Therefore, safe, effective, and affordable vaccines against both viruses are an urgent need. In this study, the HIV-1 P18I10 CTL peptide from the V3 loop of HIV-1 gp120 glycoprotein was inserted into the HPV16 L1 protein to construct chimeric HPV:HIV (L1:P18I10) VLPs. Instead of the traditional baculovirus expression vector/insect cell (BEVS/IC) system, we established an alternative mammalian 293F cell-based expression system using cost-effective polyethylenimine-mediated transfection for L1:P18I10 protein production. Compared with conventional ultracentrifugation, we optimized a novel chromatographic purification method which could significantly increase L1:P18I10 VLP recovery (~56%). Chimeric L1:P18I10 VLPs purified from both methods were capable of self-assembling to integral particles and shared similar biophysical and morphological properties. After BALB/c mice immunization with 293F cell-derived and chromatography-purified L1:P18I10 VLPs, almost the same titer of anti-L1 IgG (p = 0.6409) was observed as Gardasil anti-HPV vaccine-immunized mice. Significant titers of anti-P18I10 binding antibodies (p < 0.01%) and P18I10-specific IFN-γ secreting splenocytes (p = 0.0002) were detected in L1:P18I10 VLP-immunized mice in comparison with licensed Gardasil-9 HPV vaccine. Furthermore, we demonstrated that insertion of HIV-1 P18I10 peptide into HPV16 L1 capsid protein did not affect the induction in anti-L1 antibodies. All in all, we expected that the mammalian cell expression system and chromatographic purification methods could be time-saving, cost-effective, scalable platforms to engineer bivalent VLP-based vaccines against HPV and HIV-1.

Assessment of sinecatechins 10% ointment used as proactive sequential therapy in recurrence rate of genital warts lesions after cryotherapy. The PACT-II Trial (postablation immunomodulator treatment of condylomata with sinecatechins): a prospective assessor-blinded, multicenter, pilot trial

BACKGROUND

Cryotherapy is commonly used as ablative treatment of external genital warts (EGW). However, after cryotherapy recurrence of lesions affects on average 45% (42-70%) of subjects in the 6 months after the treatment. Sinecatechins 10% are an effective topical treatment of EGW. A low recurrence rate (<6%) was observed in pivotal phase 3 trials conducted with this product. Topical sinecatechins have demonstrated to significantly reduce the recurrence rate of EGW in subjects treated with laser therapy (The PACT-I trial). So far, no prospective data are available regarding the efficacy of sinecathechins as immunomodulator sequential therapy after cryotherapy in EGW subjects. The purpose of this study was to assess the rate of recurrence lesions after the use of topical sinecatechins 10%, as sequential proactive immunomodulation treatment after cryotherapy in subjects with EGW (The PACT-II Trial: the postablation immunomodulator treatment of condylomata with sinecatechins trial) (Trial Registration number: ISRCTN44037479).

METHODS

In a prospective, assessor-blinded, multicenter trial a total of 55 subjects with a diagnosis of multiple EGW (36 men and 19 women, mean age 47±10 years) and a mean lesion number of 9±7, after their informed consent, were enrolled in the study. All subjects were treated with cryotherapy (an average of 2 sessions). After the ablative treatment, all subjects were instructed to apply sinecatechin 10% ointment 3 times daily for 4 consecutive months. The primary study endpoint was the evaluation (assessor-blinded) of recurrent lesions after 6 months (2 month of follow-up after the conclusion of topical treatment). The secondary study endpoints were the appearance of new EGW lesions (lesions affecting area not treated by cryotherapy) and the local tolerability.

RESULTS

At baseline, the mean number of EGW lesions were 9±7. After cryotherapy, the mean lesions number were reduced to 1.6±1.8. At month 4, EGW mean lesion number were 0.2±0.4 (P=0.0001 vs. after cryotherapy). At month 6, recurrence of lesions was detected in 10 subjects (18%; 95% CI: 9-30%) with an average of 1.4 lesions. Of these recurrent lesions, 6 occurred in completely healed lesions site after cryotherapy and 8 in partially healed ones. New lesions (outside the cryotherapy treated area) were observed in 10 subjects. The product was very well tolerated. No serious side effects were reported. Three subjects reported moderate skin irritation on the application site.

CONCLUSIONS

The PACT-II Trial has shown that the recurrence rate of EGW lesions after successful cryotherapy using sinecatechins as immunomodulator sequential therapy is lower in comparison with the percentage documented in the literature without sequential therapy (20 vs. 45%). These results are in line with already published data evaluating the role of sinecatechins after laser therapy (PACT-I trial). Future comparative, double-blind controlled trials assessing the efficacy of different proactive strategies are warranted.

Episome partitioning and symmetric cell divisions: Quantifying the role of random events in the persistence of HPV infections

Human Papillomaviruses (HPV) are one of the most prevalent sexually transmitted infections (STI) and the most oncogenic viruses known to humans. The vast majority of HPV infections clear in less than 3 years, but the underlying mechanisms, especially the involvement of the immune response, are still poorly known. Building on earlier work stressing the importance of randomness in the type of cell divisions in the clearance of HPV infection, we develop a stochastic mathematical model of HPV dynamics that combines the previous aspect with an explicit description of the intracellular level. We show that the random partitioning of virus episomes upon stem cell division and the occurrence of symmetric divisions dramatically affect viral persistence. These results call for more detailed within-host studies to better understand the relative importance of stochasticity and immunity in HPV infection clearance.

Every year, infections by Human Papillomaviruses (HPV) are responsible for a large share of infectious cancers. The prevalence of HPVs is very high, which makes it a major public health issue. Fortunately, most HPV infections (80 to 90%) are cleared naturally within three years. Among the few that persist into chronic infections, the majority also naturally regress. Hence for a given HPV infection, the risk of progression towards cancerous status is low. The immune response is often invoked to explain HPV clearance in non-persisting infections, but many uncertainties remain. Besides immunity, randomness was also suggested to play an important role. Here, we examine how random events occurring during the life cycle of the virus could alter the persistence of the virus inside the host. We develop a mechanistic model that explicitly follows the dynamic of viral copies inside host cells, as well as the dynamics of the epithelium. In our model, infection extinction occurs when all viral copies end up in differentiated cells and migrate towards the surface. This can happen upon cell division during the random allocation of the episomes (i.e. independent circular DNA copies of the viral genome) or when a stem cell divides symmetrically to generate two differentiated cells. We find that the combination of these random events drastically affects infection persistence. More generally, the importance of random fluctuations could match that of immunity and calls for further studies at the within-host and the epidemiological level.

Biology of HPV Mediated Carcinogenesis and Tumor Progression

Human papillomavirus (HPV) is a ubiquitous DNA virus that infects squamous epithelia. Though HPV only encodes 8 genes, it is capable of causing cellular transformation and ultimately cancer in host cells. In this article we review the classification of HPV viruses, their genetic structure and life cycle, viral gene biology, and provide an overview of the role of HPV in cancer. We explain how the viral life cycle can lead to integration of viral DNA into the host genome leading to increased cell cycle progression, decreased apoptosis, altered DNA repair, and chromosomal instability. We describe the multifaceted roles of the canonical oncogenes E6 and E7 in promoting tumorigenesis and the important role of other viral genes in regulating cancer development. We also review how the virus actively suppresses innate and adaptive immunity to evade immune detection and promote a pro-tumorigenic microenvironment. The biology presented here will serve as a foundation to the other chapters in this edition and we hope it will incite enthusiasm for continued research on this fascinating virus that causes significant morbidity and mortality worldwide.

Human papillomavirus genotyping as a tool for cervical cancer prevention: from commercially available human papillomavirus DNA test to next-generation sequencing

The biological importance of human papillomavirus (HPV) in the field of medicine – related to cervical carcinogenesis – has been extensively reported in the last decades. For the first time, a direct correlation between cause and effect to explain a cancer development was completely achieved in medical research. Consequently, the Nobel Prize was awarded to HZ Hausen in 2008 for his efforts to understand the effects of persistent infection of oncogenic types of HPV and malignancy transformation. The aim of the present review was to summarize the principal elements of HPV characteristics and their importance in oncology.

It is established that HPV is the main etiologic agent for the development of cervical cancer. With the evolution of diagnosis and molecular biology, many tools have become essential for an early diagnosis and thereby, considerably reducing mortality. Molecular biology continues to advance and provide new perspectives with the use of reverse-transcription PCR in automation and genotyping through next-generation sequencing. This article aims to provide an overview of what is currently used in HPV diagnostic and research and future perspectives with the help of technologies such as next-generation sequencing for screening and vaccination.

The nonavalent vaccine: a review of high-risk HPVs and a plea to the CDC

Two of the leading strategies to prevent cervical cancer are prophylactic human papillomavirus (HPV) vaccination and routine Papanicolaou (Pap) testing. However, regardless of being vaccinated with first-generation (bivalent and quadrivalent) HPV vaccines at the recommended dosing schedule, many women are still found to have low- and high-grade cervical intraepithelial lesions. Studies have shown that this is largely due to: (1) first-generation vaccines only protecting against 70% of high-risk HPV types that cause cervical cancer (HPVs 16/18) and (2) vaccinated women being more prone to infection with non-protected high-risk HPV types than unvaccinated women. Fortunately, the FDA recently approved a nonavalent vaccine that protects against 5 additional high-risk HPV types that cause 20% of cervical cancers (HPVs 31/33/45/52/58), which is the only HPV vaccine currently available in the United States. Although the Advisory Committee on Immunization Practices (ACIP) recommends the nonavalent vaccine in men and women up to the age of 45 years, it does not recommend the nonavalent vaccine in those previously vaccinated with 3 doses of bivalent or quadrivalent vaccine, deeming them "adequately vaccinated". As this population is most at risk, this review serves to provide background and argue for a change in their recommendation.

Human papillomavirus infection and ocular surface disease (Review)

Human papillomavirus (HPV) infection has been implicated as a primary cause of lesions in the anogenital region, skin, oropharynx and respiratory tract. Additionally, the role of HPV in the pathogenesis of ocular surface disease has also been extensively studied. Conjunctival papilloma development has been strongly associated with the HPV infection of certain subtypes. On the other hand, the role of HPV in conjunctival pterygium, conjunctival intraepithelial neoplasia (CIN) and ocular surface squamous neoplasia (OSSN) remains controversial. Genetic predisposition and environmental factor is important in HPV hosts as regards the pathogenesis of ocular surface disease. Several studies have indicate a synergic role of HPV with ultraviolet radiation in pterygium establishment. A higher recurrence risk rate and more aggressive disease of ophthalmic pterygium is observed in cases of HPV infection. The purpose of this review was to provide a systematic review of the literature and to assist in a better understanding of the role of HPV in ocular surface disease.

Ovis aries Papillomavirus 3 in Ovine Cutaneous Squamous Cell Carcinoma

Squamous cell carcinoma (SCC) is a common malignancy affecting humans and other animals. Papillomaviruses (PVs) are frequently reported as causal agents of cutaneous benign and malignant epithelial lesions in different animal species, but only few studies have investigated their role in ovine SCC. In this study, we explore the possible involvement of the Ovine aries PVs (OaPV1, OaPV2, OaPV3) in cutaneous SCC using an integrated histological and molecular approach. Forty cutaneous SCCs from different anatomical locations of Sardinian sheep and 40 matched non-SCC samples were evaluated histologically and by polymerase chain reaction (PCR) to assess the presence of ovine PVs. In addition, DNA in situ hybridization (ISH) and reverse transcription-polymerase chain reaction (RT-PCR) were carried out to evaluate the cellular localization and viral transcriptional activity, respectively. OaPV3 DNA was detected in 26 of 40 (65%) SCCs and in 12 of 40 (30%) non-SCC samples using PCR. OaPV1 and OaPV2 were not detected. OaPV3 viral DNA was observed by ISH in malignant epithelial squamous cells of 18 of 40 (45%) SCCs. In addition, the viral transcriptional activity was identified in 24 of 40 (60%) SCCs by RT-PCR. Notably, a higher viral positivity was observed in SCCs compared with non-SCC samples. The considerable infection rate of OaPV3 in the most common skin tumor of the sheep suggests that PV could represent a key factor in the onset of ovine SCC.

Evolutionary and functional implications of hypervariable loci within the skin virome

Localized genomic variability is crucial for the ongoing conflicts between infectious microbes and their hosts. An understanding of evolutionary and adaptive patterns associated with genomic variability will help guide development of vaccines and antimicrobial agents. While most analyses of the human microbiome have focused on taxonomic classification and gene annotation, we investigated genomic variation of skin-associated viral communities. We evaluated patterns of viral genomic variation across 16 healthy human volunteers. Human papillomavirus (HPV) and Staphylococcus phages contained 106 and 465 regions of diversification, or hypervariable loci, respectively. Propionibacterium phage genomes were minimally divergent and contained no hypervariable loci. Genes containing hypervariable loci were involved in functions including host tropism and immune evasion. HPV and Staphylococcus phage hypervariable loci were associated with purifying selection. Amino acid substitution patterns were virus dependent, as were predictions of their phenotypic effects. We identified diversity generating retroelements as one likely mechanism driving hypervariability. We validated these findings in an independently collected skin metagenomic sequence dataset, suggesting that these features of skin virome genomic variability are widespread. Our results highlight the genomic variation landscape of the skin virome and provide a foundation for better understanding community viral evolution and the functional implications of genomic diversification of skin viruses.

Construction of a Transcription Map for Papillomaviruses using RACE, RNase Protection, and Primer Extension Assays

Papillomaviruses are a family of small, non-enveloped DNA tumor viruses. Knowing a complete transcription map of each papillomavirus genome can provide guidance for various papillomavirus studies. This unit provides detailed protocols to construct a transcription map of human papillomavirus type 18. The same approach can be easily adapted to other transcription map studies of any other papillomavirus genotype due to the high degree of conservation in genome structure, organization, and gene expression among papillomaviruses. The focused methods are 5'- and 3'-rapid amplification of cDNA ends (RACE), which are techniques commonly used in molecular biology to obtain full-length RNA transcript or to map a transcription start site (TSS) or an RNA polyadenylation (pA) cleavage site. Primer walking RT-PCR is a method for studying the splicing junction of RACE products. In addition, RNase protection assay and primer extension are also introduced as alternative methods in the mapping analysis.

Human papillomavirus molecular biology and disease association

Human papillomaviruses (HPVs) have evolved over millions of years to propagate themselves in a range of different animal species including humans. Viruses that have co‐evolved slowly in this way typically cause chronic inapparent infections, with virion production in the absence of apparent disease. This is the case for many Beta and Gamma HPV types. The Alpha papillomavirus types have however evolved immunoevasion strategies that allow them to cause persistent visible papillomas. These viruses activate the cell cycle as the infected epithelial cell differentiates in order to create a replication competent environment that allows viral genome amplification and packaging into infectious particles. This is mediated by the viral E6, E7, and E5 proteins. High‐risk E6 and E7 proteins differ from their low‐risk counterparts however in being able to drive cell cycle entry in the upper epithelial layers and also to stimulate cell proliferation in the basal and parabasal layers. Deregulated expression of these cell cycle regulators underlies neoplasia and the eventual progression to cancer in individuals who cannot resolve high‐risk HPV infection. Most work to date has focused on the study of high‐risk HPV types such as HPV 16 and 18, which has led to an understanding of the molecular pathways subverted by these viruses. Such approaches will lead to the development of better strategies for disease treatment, including targeted antivirals and immunotherapeutics. Priorities are now focused toward understanding HPV neoplasias at sites other than the cervix (e.g. tonsils, other transformation zones) and toward understanding the mechanisms by which low‐risk HPV types can sometimes give rise to papillomatosis and under certain situations even cancers. Copyright © 2015 John Wiley & Sons, Ltd.

Human Papillomaviruses; Epithelial Tropisms, and the Development of Neoplasia

Papillomaviruses have evolved over many millions of years to propagate themselves at specific epithelial niches in a range of different host species. This has led to the great diversity of papillomaviruses that now exist, and to the appearance of distinct strategies for epithelial persistence. Many papillomaviruses minimise the risk of immune clearance by causing chronic asymptomatic infections, accompanied by long-term virion-production with only limited viral gene expression. Such lesions are typical of those caused by Beta HPV types in the general population, with viral activity being suppressed by host immunity. A second strategy requires the evolution of sophisticated immune evasion mechanisms, and allows some HPV types to cause prominent and persistent papillomas, even in immune competent individuals. Some Alphapapillomavirus types have evolved this strategy, including those that cause genital warts in young adults or common warts in children. These strategies reflect broad differences in virus protein function as well as differences in patterns of viral gene expression, with genotype-specific associations underlying the recent introduction of DNA testing, and also the introduction of vaccines to protect against cervical cancer. Interestingly, it appears that cellular environment and the site of infection affect viral pathogenicity by modulating viral gene expression. With the high-risk HPV gene products, changes in E6 and E7 expression are thought to account for the development of neoplasias at the endocervix, the anal and cervical transformation zones, and the tonsilar crypts and other oropharyngeal sites. A detailed analysis of site-specific patterns of gene expression and gene function is now prompted.

Clinical course of recurrent respiratory papillomatosis: comparison between aggressiveness of human papillomavirus-6 and human papillomavirus-11

BACKGROUND

Recurrent respiratory papillomatosis (RRP) is mainly associated with human papillomavirus (HPV)6 or HPV11. The purpose of this study was to compare clinical outcome, aggressiveness, and treatment response between HPV6- and HPV11-associated RRP.

METHODS

A retrospective cohort of 55 patients with RRP (1974-2012) was used. Surgical interventions (n = 814) were analyzed, and complications scored. HPV6/11-specific polymerase chain reaction (PCR) was performed on RRP biopsies.

RESULTS

Seventy-six percent of patients (42 of 55) were infected with HPV6 and 24% (13 of 55) with HPV11. The HPV11 group had anatomically more widespread disease. The expected number of surgical interventions was higher in the younger age (<22.4 years) HPV11 group, and the older age (<22.4 years) HPV6 group. Regardless of HPV type, earlier age of onset of RRP resulted in a higher number of surgical interventions.

CONCLUSION

Anatomically, HPV11-associated RRP behaves more aggressively. Younger patients with HPV11 and older patients with HPV6 experience a worse clinical course of RRP.

Impact of inhibitors and L2 antibodies upon the infectivity of diverse alpha and beta human papillomavirus types

The licensed human papillomavirus (HPV) vaccines elicit type-restricted immunity but do not target cutaneous HPV types of the beta genus that are associated with non-melanoma skin cancer in immune-compromised patients, and it is unclear if these diverse types share a common mechanism of infection. Residues 11-88 of minor capsid protein L2 contain cross-protective epitopes, and vaccination with concatamers of this region derived from as many as eight alpha HPV (L2 α11-88x8) is being developed as an alternative prophylactic vaccine with potentially broader efficacy. There is also interest in developing broadly protective topical microbicides, such as carrageenan or heparin that block HPV receptor interactions, or small molecule inhibitors of infection. Here we have examined several inhibitors of HPV infection and antisera to L2 α11-88x8 for their breadth of activity against infection by 34 HPV types from within both the alpha and beta families using pseudovirions (PsV) carrying a luciferase reporter as surrogates for native virus. We observed that both heparin and carrageenan prevented infection by mucosatropic HPV types, but surprisingly PsV of several epidermotropic alpha4 and beta HPV types exhibited increased infectivity especially at low inhibitor concentrations. Furin and γ-secretase inhibitors and L2 α11-88x8 antiserum blocked infection by all HPV PsV types tested. These findings suggest that the distinct tropism of mucosal and cutaneous HPV may reflect distinct cell surface receptor interactions, but a common uptake mechanism dependent upon furin and γ-secretase proteolytic activities. Carrageenan, which is being tested as a vaginal microbicide, broadly inhibited infection by the high-risk mucosatropic HPV PsV, but not most skin tropic alpha and beta HPV. Vaccination with an L2 multimer derived exclusively from alpha papillomavirus sequences induced antibodies that broadly neutralized PsV of all 34 HPVs from within both the alpha and beta families, suggesting each displays conserved L2 neutralizing epitopes.

Cervicovaginal secretions protect from human papillomavirus infection: effects of vaginal douching

OBJECTIVE

Cervicovaginal secretions (CVSs) are reported to protect against human papillomavirus (HPV) infection. Although vaginal douching is known to clear both viral inoculants and CVSs, its effect on CVSs in women with HPV infection is unknown.

MATERIALS AND METHODS

The in vitro HPV pseudovirus infection system was used to test the protective activity of CVSs against HPV infection in samples collected before and after vaginal douching. To simulate different time points of vaginal douching in relation to viral exposure, the cell CVS reconstitute was washed after different viral exposure durations.

RESULTS

In the CVSs of premenopausal and postmenopausal women who did not perform douching, the CVSs inhibited HPV infection by 56.7 ± 1.8% and 53.6 ± 2.5%, respectively; in women who had performed douching, the CVSs inhibited HPV infection by only 31.2 ± 7.1%, which was significantly lower (p < 0.01). Cell washing effectively cleared 60-90% of the infectious load with the greatest activity occurring within 30 minutes after inoculation. In the presence of CVSs, a sustained inhibition of HPV infection existed for up to 8 hours after HPV exposure, and cell washing increased the clearance to up to 82-93% of the infectious load.

CONCLUSION

This study confirms the protective activity of CVSs against HPV infection regardless of age. In this in vitro study, the net effect of douching was found to be beneficial.

Murine skin and vaginal mucosa are similarly susceptible to infection by pseudovirions of different papillomavirus classifications and species

Depending upon viral genotype, productive papillomavirus infection and disease display preferential tropism for cutaneous or mucosal stratified squamous epithelia, although the mechanisms are unclear. To investigate papillomavirus entry tropism, we used reporter pseudovirions based on various cutaneous and mucosal papillomavirus species, including the recently identified murine papillomavirus. Pseudovirus transduction of BALB/c mice was examined using an improved murine skin infection protocol and a previously developed cervicovaginal challenge model. In the skin, HPV5, HPV6, HPV16, BPV1 and MusPV1 pseudovirions preferentially transduced keratinocytes at sites of trauma, similar to the genital tract. Skin infection, visualized by in vivo imaging using a luciferase reporter gene, peaked between days 2-3 and rapidly diminished for all pseudovirion types. Murine cutaneous and genital tissues were similarily permissive for pseudovirions of HPV types 5, 6, 8, 16, 18, 26, 44, 45, 51, 58 and animal papillomaviruses BPV1 and MusPV1, implying that papillomavirus' tissue and host tropism is governed primarily by post-entry regulatory events in the mouse.

Detection of human papillomavirus (HPV) L1 gene DNA possibly bound to particulate aluminum adjuvant in the HPV vaccine Gardasil

Medical practitioners in nine countries submitted samples of Gardasil (Merck & Co.) to be tested for the presence of human papillomavirus (HPV) DNA because they suspected that residual recombinant HPV DNA left in the vaccine might have been a contributing factor leading to some of the unexplained post-vaccination side effects. A total of 16 packages of Gardasil were received from Australia, Bulgaria, France, India, New Zealand, Poland, Russia, Spain and the United States. A nested polymerase chain reaction (PCR) method using the MY09/MY11 degenerate primers for initial amplification and the GP5/GP6-based nested PCR primers for the second amplification were used to prepare the template for direct automated cycle DNA sequencing of a hypervariable segment of the HPV L1 gene which is used for manufacturing of the HPV L1 capsid protein by a DNA recombinant technology in vaccine production. Detection of HPV DNA and HPV genotyping of all positive samples were finally validated by BLAST (Basic Local Alignment Search Tool) analysis of a 45-60 bases sequence of the computer-generated electropherogram. The results showed that all 16 Gardasil samples, each with a different lot number, contained fragments of HPV-11 DNA, or HPV-18 DNA, or a DNA fragment mixture from both genotypes. The detected HPV DNA was found to be firmly bound to the insoluble, proteinase-resistant fraction, presumably of amorphous aluminum hydroxyphosphate sulfate (AAHS) nanoparticles used as adjuvant. The clinical significance of these residual HPV DNA fragments bound to a particulate mineral-based adjuvant is uncertain after intramuscular injection, and requires further investigation for vaccination safety.

Differential binding patterns to host cells associated with particles of several human alphapapillomavirus types

The focus of this research was to compare the binding profiles of human papillomavirus (HPV) 11, 16, 18 and 45 virus-like particles (VLPs) to HaCaT cells and to the extracellular matrix (ECM) secreted by these cells. All four HPV types tested bind to a component(s) of the ECM. HPV11 VLP binding is blocked when the ECM is pretreated with an anti-laminin 5 (LN5) polyclonal antibody. A series of treatments utilizing heparins and heparinase revealed that HPV18 VLPs are dependent on heparan sulfates (HS) for binding to cells and ECM. HPV16 and HPV45 VLPs are dependent on HS for binding to HaCaT cells and dependent on both HS and LN5 for binding to ECM. These studies emphasize the need to study the binding characteristics of different HPV types before applying universal binding principles to all papillomaviruses.