Human papova (wart) virus

Improved detection of low-frequency within-host variants from deep sequencing: A case study with human papillomavirus

High-coverage sequencing allows the study of variants occurring at low frequencies within samples, but is susceptible to false-positives caused by sequencing error. Ion Torrent has a very low single nucleotide variant (SNV) error rate and has been employed for the majority of human papillomavirus (HPV) whole genome sequences. However, benchmarking of intrahost SNVs (iSNVs) has been challenging, partly due to limitations imposed by the HPV life cycle. We address this problem by deep sequencing three replicates for each of 31 samples of HPV type 18 (HPV18). Errors, defined as iSNVs observed in only one of three replicates, are dominated by C→T (G→A) changes, independently of trinucleotide context. True iSNVs, defined as those observed in all three replicates, instead show a more diverse SNV type distribution, with particularly elevated C→T rates in CCG context (CCG→CTG; CGG→CAG) and C→A rates in ACG context (ACG→AAG; CGT→CTT). Characterization of true iSNVs allowed us to develop two methods for detecting true variants: (1) VCFgenie, a dynamic binomial filtering tool which uses each variant's allele count and coverage instead of fixed frequency cut-offs; and (2) a machine learning binary classifier which trains eXtreme Gradient Boosting models on variant features such as quality and trinucleotide context. Each approach outperforms fixed-cut-off filtering of iSNVs, and performance is enhanced when both are used together. Our results provide improved methods for identifying true iSNVs in within-host applications across sequencing platforms, specifically using HPV18 as a case study.

The human Papillomavirus twilight zone - Latency, immune control and subclinical infection

The incorporation of HPV DNA testing into cervical screening programs has shown that many HPV-positive women are cytologically normal, with HPV-positivity fluctuating throughout life. Such results suggest that papillomaviruses may persist in a latent state after disease clearance, with sporadic recurrence. It appears that virus latency represents a narrow slot in a wider spectrum of subclinical and possibly productive infections. Clinical studies, and animal model infection studies, suggested a key role for host immune surveillance in maintaining such asymptomatic infections, and although infections may also be cleared, most studies have used the term 'clearance' to describe a situation where the presence of HPV DNA falls below the clinical detection level. Given our knowledge of papillomavirus immune evasion strategies and the restricted pattern of viral gene expression required for 'basal cell' persistence, the term 'apparent clearance' and 'subclinical persistence' of infection may better summarise our understanding. Subclinical infection also encompasses the lag phase, which occurs between infection and lesion development. This is dependent on infection titre, with multifocal infections developing more rapidly to disease. These concepts can usefully influence patient management where HPV-positivity occurs sometime after the onset of sexual activity, and where vertical transmission is suspected despite a lag period.

Human papillomavirus genomics: Understanding carcinogenicity

Human papillomavirus (HPV) causes virtually all cervical cancers and many cancers at other anatomical sites in both men and women. However, only 12 of 448 known HPV types are currently classified as carcinogens, and even the most carcinogenic type - HPV16 - only rarely leads to cancer. HPV is therefore necessary but insufficient for cervical cancer, with other contributing factors including host and viral genetics. Over the last decade, HPV whole genome sequencing has established that even fine-scale within-type HPV variation influences precancer/cancer risks, and that these risks vary by histology and host race/ethnicity. In this review, we place these findings in the context of the HPV life cycle and evolution at various levels of viral diversity: between-type, within-type, and within-host. We also discuss key concepts necessary for interpreting HPV genomic data, including features of the viral genome; events leading to carcinogenesis; the role of APOBEC3 in HPV infection and evolution; and methodologies that use deep (high-coverage) sequencing to characterize within-host variation, as opposed to relying on a single representative (consensus) sequence. Given the continued high burden of HPV-associated cancers, understanding HPV carcinogenicity remains important for better understanding, preventing, and treating cancers attributable to infection.

Human papillomaviruses: diversity, infection and host interactions

Human papillomaviruses (HPVs) are an ancient and highly successful group of viruses that have co-evolved with their host to replicate in specific anatomical niches of the stratified epithelia. They replicate persistently in dividing cells, hijack key host cellular processes to manipulate the cellular environment and escape immune detection, and produce virions in terminally differentiated cells that are shed from the host. Some HPVs cause benign, proliferative lesions on the skin and mucosa, and others are associated with the development of cancer. However, most HPVs cause infections that are asymptomatic and inapparent unless the immune system becomes compromised. To date, the genomes of almost 450 distinct HPV types have been isolated and sequenced. In this Review, I explore the diversity, evolution, infectious cycle, host interactions and disease association of HPVs.

Cancers in Humans: A Lifelong Search for Contributions of Infectious Agents, Autobiographic Notes

This review briefly covers periods of my early life; experiences during World War II; my school education; and my period as a medical student in Bonn, Hamburg, and Düsseldorf. Mainly emphasized is my scientific career after finishing my medical internship and periods as a postdoc at the Institute for Microbiology in Düsseldorf and the Virus Laboratories of the Children's Hospital of Philadelphia and as Senior Research Fellow at the Institute of Virology in Würzburg, Germany. Subsequent appointment as chairman of the newly established Institute of Virology, University of Erlangen-Nürnberg, in a similar position at the University of Freiburg, and then for 20 years as scientific director of the Deutsches Krebsforschungszentrum, Heidelberg, are discussed, covering the scientific developments during these periods. The emeritus period since 2003 was particularly exciting, leading to the discovery of autonomously replicating plasmids, derived from specific bacteria, and their link to common human cancers (colon, breast, and prostate).

History of High-Resolution Anoscopy

High-resolution anoscopy (HRA) is a form of low-resolution anal microscopy currently utilized in the screening and management of anal squamous dysplasia. No randomized controlled trials, national or international guidelines exist on the use of HRA for this purpose. Much of our understanding of this entity has been adapted from the literature on cervical squamous dysplasia, including the technique of HRA itself. Epidemiologic evidence has shown that the prevalence and incidence of anal dysplasia is highest in HIV-positive populations. The history of this technique parallels the evolution of our understanding of anal dysplasia. To understand the history of the use of HRA and its place in the screening and management of anal squamous dysplasia, we discuss key advances in the understanding of human papillomavirus-related squamous dysplasia. We begin with early reports in the field establishing the link between this virus and squamous dysplasia, through the marked increase in anal cancer seen with the onset of the HIV epidemic, the identification of relevant populations at risk, the performance of the test itself, to its use today.

Searching for human oncoviruses: Histories, challenges, and opportunities

Oncoviruses contribute significantly to cancer burden. A century of tumor virological studies have led to the discovery of seven well-accepted human oncoviruses, cumulatively responsible for approximately 15% of human cancer cases. Virus-caused cancers are largely preventable through vaccination. Identifying additional oncoviruses and virus-caused tumors will advance cancer prevention and precision medicine, benefiting affected individuals, and society as a whole. The historic success of finding human oncoviruses has provided a unique lesson for directing new research efforts in the post-sequencing era. Combing the experiences from these pioneer studies with emerging high-throughput techniques will certainly accelerate new discovery and advance our knowledge of the remaining human oncoviruses.

Giant Condyloma Acuminata of the Inguinal Region

A 70-year-old male presented with a progressively increasing polypoidal lesion in the right inguinal region since last 10 years. He had no anal or penile lesion. Excision biopsy was done under spinal anaesthesia. Histopathology showed it to be a giant condyloma acuminata. We report this case due to its large size and its location in inguinal region without pre-existing anal or rectal lesion.

Human papillomavirus genomics: past, present and future

Human papillomaviruses (HPV) are a group of divergent DNA viruses, of which a select few evolutionarily related HPVs have emerged to be highly oncogenic and of significant medical importance. Essentially all cases of cervical cancer, as well as a subset of other anogenital and oral cancers are caused by this limited set of HPV types. At present, over 150 HPV types have been identified and may be classified into genera, species and types based upon comparison of the viral genome. Established nucleotide phylogenies sort the highly pathogenic HPV types to the genus Alphapapillomavirus (α-PV). A species group includes viral types with 60-70% genomic nucleotide similarity that share a most-recent common ancestor; for example the species group's alpha-9 (HPV16-related) and alpha-7 (HPV18-related), contain the majority of known oncogenic HPV types. Genomes from the same HPV type with 1-10% nucleotide differences designate HPV variant lineages. The established nucleotide variations observed in extant HPV genomes have been fixed through evolutionary processes prior to human population expansion and global dissemination. To characterize viral types and variants associated with pathology for clinical applications (e.g. screening), molecular epidemiological studies have proven essential for identifying links between HPV natural history and carcinogenicity. This chapter presents a historical account of HPV genomics in the context of major discoveries and advances over the past 2 thousand years.

Near-infrared Raman Microspectroscopy Detects High-risk Human Papillomaviruses

BACKGROUND

Detecting human papillomaviruses (HPVs) infection in cervical cells is an exceedingly important part of the clinical management of cervical dysplasia. Current guidelines in women's health outline the need for both the Papanicolaou test as well as high-risk HPV testing. Testing for HPV is expensive, is time-consuming, and requires experienced technicians.

METHODS

Two sets of near-infrared Raman microspectroscopy experiments were conducted using a Raman confocal microscope system. First, Raman spectra were acquired from four different cell culture lines, two positive for HPV (HeLa, SiHa), one negative for HPV, but malignant (C33A), and one normal, HPV-negative line (NHEK). The three malignant lines were all derived from cervical cells. Second, Raman spectra were acquired from deidentified patient samples that were previously tested for the presence of high-risk HPV.

RESULTS

The spectra from the cell culture lines and the patient samples contained many statistically significant differences. Using sparse multinomial logistic regression to classify the data led to classification accuracies of 89% to 97% for the cell culture samples and 98.5% for the patient samples.

CONCLUSIONS

Raman micro-spectroscopy can be used to detect HPV and differentiate among specific HPV strains. This technique may provide health providers with a new method for quickly testing cell samples for the presence of HPV.

Evaluation of a novel broad-spectrum PCR-multiplex genotyping assay for identification of cutaneous wart-associated human papillomavirus types

A large number of human papillomavirus (HPV) types, distributed over five papillomavirus genera, are detectable in the skin. HPV types belonging to the alpha, gamma, and mu genera have been detected in cutaneous warts. A state-of-the-art HPV genotyping assay for these cutaneous wart-associated HPV types does not exist although warts constitute a highly prevalent skin condition, especially in children (33%) and organ transplant recipients (45%). Cutaneous warts are again the focus of attention as their clinical relevance rises with the increasing number of chronically immunosuppressed patients. The objective of this study was to develop and evaluate a DNA-based genotyping system for all known cutaneous wart-related HPV types using PCR and Luminex xMAP technology. The broad-spectrum PCR amplified DNA of all known wart-associated HPV types from the genera alpha (HPVs 2, 3, 7, 10, 27, 28, 29, 40, 43, 57, 77, 91, and 94), gamma (HPVs 4, 65, 95, 48, 50, 60, and 88), mu (HPVs 1 and 63), and nu (HPV41). The probes were evaluated using plasmid HPV DNA and a panel of 45 previously characterized cutaneous wart biopsy specimens showing high specificity. HPV was also identified in 96% of 100 swabs from nongenital cutaneous warts. HPV types 1, 2, 27, and 57 were the most prevalent HPV types detected in 89% of the swabs. In conclusion, this Luminex-based genotyping system identifies all known cutaneous wart HPV types including phylogenetically related types, is highly HPV type specific, and is suitable for large-scale epidemiological studies.

Pulsed dye laser: what's new in non-vascular lesions?

BACKGROUND AND OBJECTIVE

In dermatology, the pulsed dye laser (PDL) is the therapeutic instrument of choice for treating most superficial cutaneous vascular lesions. In addition, clinical experience over the last decade allowed us to treat patients with an ever increasing number of non-vascular indications. The purpose of this report is to summarize and critically appraise the scientific evidence that support the role of PDL in treating non-vascular skin lesions.

METHODS

A literature-based study has been conducted, including the review of publications over the period January 1995 to December 2006, using the Medline Database. We also included our own experience in managing non-vascular lesions with the PDL. Four sets of preoperative and postoperative photos are presented.

RESULTS

For viral skin lesions, PDL proved to be an alternative to other therapy options. This applies particularly to periungual warts and mollusca contagiosa. The mechanism of PDL with inflammatory dermatoses has not yet been elucidated. The effect seems to be better if there is a vascular component to the disease. With most of these indications (such as psoriasis and acne), PDL currently plays a rather minor or complementary role. Regarding collagen remodelling (hypertrophic scars, keloids, stretch marks, and skin rejuvenation), the question of whether a therapy makes sense or not has to be decided from case to case.

CONCLUSION

With PDL, it is possible to achieve good results with numerous, partly less well-known indications (i.e. lupus erythematosus). With other diseases, PDL has so far been considered to be a complementary therapy method or to be in an experimental state.

Human papillomavirus type 31b infection of human keratinocytes does not require heparan sulfate

Oncogenic human papillomaviruses (HPVs) are difficult to study experimentally as they replicate at low levels in vivo. This has precluded the purification of high-risk HPV virions from in vivo lesions. Virus-like particles (VLPs) and pseudovirions from low- and high-risk HPV types can emulate various aspects of HPV virion attachment and infections. These studies suggest that HPV infection is mediated by alpha6-integrin and/or heparan-sulfonated receptors. However, whether VLPs and pseudovirions accurately reflect the infection process of HPV virions has not been verified. We generated infectious HPV31b virions from organotypic (raft) tissues and performed experimental infections in a variety of cells. Successful infection following viral attachment, internalization, and nuclear transport was assayed by detecting newly synthesized, spliced HPV transcripts using reverse transcription (RT)-PCR or RT-quantitative PCR. Most human epithelial cells were infected with HPV31b at a multiplicity of infection as low as 1 to 10 viral genome equivalents per cell. HPV31b infection was detected in other cell lines, including COS-7 monkey kidney cells, but higher viral multiplicities of infection were required. Heparin preparations of various molecular weights or heparinase I treatment of cells prevented HPV31b infection of COS-7 cells and C-33A human cervical cancer cells in reproducible and dose-dependent manners. However, these reagents were unable to block infection of human keratinocytes, including HaCaT and N/TERT-1 cells and low-passage human foreskin keratinocytes. These data suggest that HPV31b infection of human keratinocytes, the natural host cell for HPV infections in vivo, does not require a heparan-sulfonated receptor, whereas heparan sulfate is important for infection of some other cells.

Infectious human papillomavirus type 31b: purification and infection of an immortalized human keratinocyte cell line

Human papillomaviruses (HPVs) are aetiological agents of human malignancies, most notably cervical cancers. The life-cycles of HPVs are dependent on epithelial differentiation, and this has impeded many basic studies of HPV biology. The organotypic (raft) culture system supports epithelial differentiation such that infectious virions are synthesized in raft tissues from epithelial cells that replicate extrachromosomal HPV genomes. The CIN-612 9E cell line maintains episomal copies of HPV type 31b (HPV31b), an HPV type associated with cervical cancers. Many previous studies, including our own, have focused on characterizing the later stages of the HPV31b life-cycle in CIN-612 9E raft tissues. In this study, we have used the raft system to generate large numbers of HPV31b viral DNA (vDNA)-containing particles. We found a biologically contained homogenization system to be efficient at virion extraction from raft epithelial tissues. We also determined that vDNA-containing particles could be directly quantified from density-gradient fractions. Using an RT-PCR assay, the presence of newly synthesized, spliced HPV31b transcripts was detected following HPV31b infection of the immortalized HaCaT epithelial cell line. Spliced E6 and E1( wedge )E4 RNAs were detected using a single round of RT-PCR from cells infected with a dose as low as 1.0 vDNA-containing particle per cell. Spliced E1*I,E2 transcripts were found in cells infected with an HPV31b dose as low as 10 vDNA-containing particles per cell. Infectivity was blocked by HPV31 antiserum, but was not affected by DNase I. This work lays a foundation for a detailed analysis of the early events in HPV infection.

Squaric acid immunotherapy for warts in children

BACKGROUND

Warts are a common pediatric skin infection caused by human papillomavirus (HPV). Spontaneous clearance of warts involves anti-HPV immunity, which may be enhanced by contact sensitizers. Squaric acid dibutylester (SADBE) is a nonmutagenic sensitizing agent useful for immunotherapy of alopecia areata.

OBJECTIVE

We hypothesized that SADBE home application might be effective therapy for warts.

METHODS

An open-label, retrospective study of 61 children with warts was performed. Sensitization with 2% SADBE on the forearm was followed with home application of 0.2% SADBE to warts 3 to 7 nights per week for at least 3 months.

RESULTS

Complete clearing occurred in 34 patients (58%), with a mean duration of therapy of 7 weeks. Partial clearing occurred in 11 (18%), and no response in 14 (24%). Clearance correlated with plantar distribution, wart duration under 2 years (P <.05), and first-line therapy with SADBE. Mild side effects occurred in one third of patients, were limited most commonly to mild erythema at the site of sensitization, and necessitated discontinuation of therapy in only 2 patients.

CONCLUSION

SADBE topical immunotherapy is a safe, effective option for home therapy of warts in children.

Juvenile onset recurrent respiratory papillomatosis: possibilities for successful antiviral therapy

Recurrent respiratory papillomatosis (RRP) is a potentially devastating disease that can have significant morbidity, and can even result in mortality due to airway compromise or, less commonly, malignant transformation. Two distinct types of RRP exist: adult-onset RRP (AO-RRP) and juvenile-onset RRP (JO-RRP). Acquisition of human papillomavirus (HPV), the causative agent of RRP, is believed to occur in the peripartum period in the case of JO-RRP, with disease symptoms (primarily hoarseness) becoming apparent during the first several years of life. Treatment currently consists of surgical debulking of the papillomas to relieve airway obstruction. However, numerous antiviral therapies have also been evaluated, albeit primarily under uncontrolled settings. This article will review the biology, natural history and management of HPV infection, with particular emphasis on JO-RRP.

Pulsed dye laser therapy for viral warts

Twenty-eight patients with 103 recalcitrant and 20 simple viral warts were treated with the Cynosure PhotoGenica V pulsed dye laser at 585 nm, and fluencies of 6.0-9.0 J/cm(2). An eradication rate of 92% for recalcitrant warts after an average of 2.1 (range 1-7) treatments and 75% for simple warts after an average of 1.6 (range 1-2) treatments was achieved with a mean follow-up period of 7.2 (range 3-15) months. Mild hypopigmentation was noted in one patient and superficial infection in another. Unlike ablative treatment modalities, with pulsed dye laser therapy, no wound was created thus avoiding prolonged postoperative pain, disability and scarring. Treatment was well tolerated by patients, most of whom returned to work or normal activities immediately postoperatively. Pulsed dye laser is an effective treatment for both recalcitrant and simple warts. It is the treatment of choice for these lesions in cosmetically sensitive areas.

Targeted expression of the E6 and E7 oncogenes of human papillomavirus type 16 in the epidermis of transgenic mice elicits generalized epidermal hyperplasia involving autocrine factors

The E6 and E7 early genes of human papillomavirus type 16 have been shown in vitro to play a central role in the transforming capability of this virus. To explore their effects on differentiating epithelial cells in vivo, we used a bovine cytokeratin 10 (K10) promoter to target the expression of E6 and E7 to the suprabasal layers of the epidermis of transgenic mice. In two different lines of mice efficiently expressing the transgene, animals displayed generalized epidermal hyperplasia, hyperkeratosis and parakeratosis in the skin and the forestomach, both known to be sites of K10 expression. Northern (RNA) blot analysis revealed high levels of E6 and E7 transcripts, and in situ hybridizations localized these transcripts to the suprabasal strata of epidermis. In vivo labeling of proliferating cells showed two distinct effects of E6 and E7 expression in the epidermis: (i) an increase in the number of growing cells in the undifferentiated basal layer and (ii) abnormal proliferation of differentiated cells in the suprabasal strata. The expression of c-myc in the skin of transgenics was higher than that in control animals. The induction of c-myc transcription by topical application of tetradecanoyl phorbol acetate was prevented by simultaneous treatment with transforming growth factor beta 1 in nontransgenic skin but not in transgenic skin. In addition, transforming growth factor alpha was found to be overexpressed in the suprabasal layers of the transgenic epidermis. These findings suggest that autocrine mechanisms are involved in the development and maintenance of epidermal hyperplasia. Animals of both lines developed papillomas in skin sites exposed to mechanical irritation and wounding, suggesting that secondary events are necessary for progression to neoplasia. Collectively, these results provide new insights into the tumor promoter activities of human papillomavirus type 16 in epithelial cells in vivo.

Targeted expression of the E6 and E7 oncogenes of human papillomavirus type 16 in the epidermis of transgenic mice elicits generalized epidermal hyperplasia involving autocrine factors

The E6 and E7 early genes of human papillomavirus type 16 have been shown in vitro to play a central role in the transforming capability of this virus. To explore their effects on differentiating epithelial cells in vivo, we used a bovine cytokeratin 10 (K10) promoter to target the expression of E6 and E7 to the suprabasal layers of the epidermis of transgenic mice. In two different lines of mice efficiently expressing the transgene, animals displayed generalized epidermal hyperplasia, hyperkeratosis and parakeratosis in the skin and the forestomach, both known to be sites of K10 expression. Northern (RNA) blot analysis revealed high levels of E6 and E7 transcripts, and in situ hybridizations localized these transcripts to the suprabasal strata of epidermis. In vivo labeling of proliferating cells showed two distinct effects of E6 and E7 expression in the epidermis: (i) an increase in the number of growing cells in the undifferentiated basal layer and (ii) abnormal proliferation of differentiated cells in the suprabasal strata. The expression of c-myc in the skin of transgenics was higher than that in control animals. The induction of c-myc transcription by topical application of tetradecanoyl phorbol acetate was prevented by simultaneous treatment with transforming growth factor beta 1 in nontransgenic skin but not in transgenic skin. In addition, transforming growth factor alpha was found to be overexpressed in the suprabasal layers of the transgenic epidermis. These findings suggest that autocrine mechanisms are involved in the development and maintenance of epidermal hyperplasia. Animals of both lines developed papillomas in skin sites exposed to mechanical irritation and wounding, suggesting that secondary events are necessary for progression to neoplasia. Collectively, these results provide new insights into the tumor promoter activities of human papillomavirus type 16 in epithelial cells in vivo.

Pathobiology of papillomavirus-related cervical diseases: prospects for immunodiagnosis

In recent years, the relationship between human papillomaviruses (HPV) and genital neoplasia has been explored intensively, and a molecular basis for the role of HPV in the genesis of these diseases has been convincingly demonstrated. These findings have provided justification for efforts to apply this molecular information to the early detection and possible prevention of HPV-related neoplasia. The technology of detecting viral nucleic acids in genital fluids brought with it initial hopes that it would serve to identify women at risk for having or developing precancers or cancers of the cervix. Subsequent studies, however, have demonstrated limitations of the technology for predicting future disease. Recently, molecular immunology has complemented these prior efforts, with the intent to identify serological indices of exposure to HPV and perhaps delineate individuals at risk. The molecular basis for this approach, its limitations, and future prospects for immunodiagnosis are the subject of this review.

Plantar warts

Plantar warts are an extremely common problem which can be very painful and debilitating. As is often the case with common problems, the knowledge of the disease and its treatments is inversely proportional to the frequency of the disease. Often the lay person knows as much and has as strong an opinion on treatment as the treating physician. In addition, most communities have someone who has the reputation of being able to bewitch warts off. This review will attempt to make some order of myriad facts and suppositions regarding this infection. Hopefully, this will aid the physician in the diagnosis and treatment of the patient with plantar warts.

Unusual HPV types in oral warts in association with HIV infection

Human papillomaviruses (HPV) are associated with certain oral soft tissue lesions, such as papillomas, warts, condylomata, and focal epithelial hyperplasia (FEH). HPV types 2, 6, 11, 16, and 18 have been identified in some of these oral lesions, while HPV 13 and 32 are associated with FEH. Little is known about the HPV types in oral warts of persons infected with human immunodeficiency virus (HIV). In this study, oral warts in 17 HIV-seropositive individuals were biopsied. Southern blot analyses were performed and the HPV types found were HPV 7 (7/17), 13 (1/17), 32 (1/17), and 18 (1/17). The presence of HPV type 7 is unusual in that it normally is found only in butcher's warts. There was no correlation between HPV type, histopathology, and clinical appearance of the lesions examined, except that the flat (FEH type) warts contained HPV types 13, 18 and 32 (1 of each). HIV infection appears to predispose individuals to oral infection with unusual HPV types.

The use of cis-retinoic acid in recurrent respiratory papillomatosis of the larynx: a randomized pilot study

We undertook a study of 13-cis-retinoic acid to evaluate its use as an adjuvant to laser surgery in the management of recurrent respiratory papillomatosis. In a double-blind study using placebo, four of the six subjects treated with this agent experienced recurrence while receiving therapy, with two requiring further surgical intervention. All six experienced toxicity, necessitating the withdrawal from therapy of two and dose reduction in three. When it became apparent that the therapy was ineffective, and caused toxicity, the study was closed.

Proteins present in bovine papillomavirus particles

Analysis by two-dimensional gel electrophoresis and silver staining of heavy full, light full, and empty bovine papillomavirus particles has shown that the major capsid protein L1 is highly modified. Besides exhibiting at least 13 isoelectric point variants of approximately the same molecular mass (54 kilodaltons), it is suggested that an additional heavier protein chain (69 kilodaltons) is also derived from L1 by glycosylation. These modifications may stabilize the particle structure. Treatment with neuraminidase reduces the number of modification products detectable, with a concomitant increase in the more basic forms of L1. Although it was not possible to detect histones in any of the preparations, proteins of similar molecular mass were detected. Therefore, it is suggested that the basic tails of L1 bind to the DNA in a manner similar to that of histone. Calculation of the theoretical mobilities of the papillomavirus proteins shows good agreement with the actual position of L1 and its isoelectric point variants and suggests that two of the proteins with molecular masses similar to those of the histones may actually be coded by the bovine papillomavirus E7 and E5 open reading frames.

Detection of human papovavirus antigen in oral papillary lesions

The papillary lesions of oral verruca vulgaris, condyloma acuminatum, and verrucous carcinoma were examined for the presence of papovavirus antigens by the peroxidase-antiperoxidase immunohistochemical methods. The antigens could be detected in the nuclei of cells only in the stratum granulosum and stratum corneum in some cases of verruca vulgaris and condyloma acuminatum but in no case of verrucous carcinoma.

A new type of papillomavirus DNA, its presence in genital cancer biopsies and in cell lines derived from cervical cancer

DNA of a new papillomavirus type was cloned from a cervical carcinoma biopsy. Two EcoRI clones of 7.8 and 6.9 kb in length were obtained, the latter contained a 900-bp deletion. The BamHI fragments of both clones were used to characterize the DNA. It represents a distinct type of papillomavirus as determined by its size, its cross-hybridization with DNA of other papillomavirus types under conditions of low stringency only, the co-linear alignment of its genome with HPV 6 and HPV 16 prototypes and its occasional occurrence as oligomeric episomes. We tentatively propose to designate it as HPV 18. DNA hybridizing with HPV 18 under stringent conditions was detected in 9/36 cervical carcinomas from Africa and Brazil, in 2/13 cervical tumors from Germany and 1/10 penile carcinomas. Benign tumors (17 cervical dysplasias, 29 genital warts), eight carcinomata in situ and 15 biopsies of normal cervical tissue were devoid of detectable HPV 18 DNA. HPV 18-related DNA was found, however, in cells of the HeLa, KB and C4-1 lines all derived from cervical cancer. The state of the viral DNA was investigated in four cervical cancer biopsies. The data reveal that the DNA might be integrated into the host cell genome. One tumor provided evidence for head to tail tandem repeats some of which persisted as circular episomes.

Viral etiology of juvenile- and adult-onset squamous papilloma of the larynx

Juvenile- and adult-onset laryngeal papillomas were examined for the presence of a human papillomavirus (HPV) genome and capsid antigens. DNA was isolated from a portion of tissue removed for therapeutic purposes, and the presence of a papillomavirus genome was detected by Southern transfer analysis. The viral DNA found in the 12 juvenile-onset and the 8 adult-onset laryngeal papillomas examined was identified as HPV-6 on the basis of size, restriction endonuclease digestion patterns, and homology detected under stringent conditions. Restriction endonuclease analysis of the viral genomes revealed at least four different subtypes, designated HPV-6c through HPV-6f. The most common subtype, HPV-6c, was detected in over half of the papillomas studied, including both juvenile and adult types. The remaining tissue was fixed and processed for immunocytochemistry. The immunoperoxidase technique was used with an antiserum that reacts with capsid antigen(s) common to all HPV serotypes. HPV antigen was found in two of the juvenile-onset papillomas and two of the adult-onset papillomas. The antigen was localized to the nucleus and was distributed in the superficial layers of the epithelium. HPV capsid antigen had not previously been detected in cases of adult-onset papilloma, and the HPV genome in both juvenile- and adult-onset laryngeal papillomas had not been characterized. Despite the absence of detectable viral antigen in most of the specimens examined, the presence of the HPV genome provides strong evidence for the papillomavirus etiology of these tumors.

Biochemical characterization of two types of human papillomaviruses associated with epidermodysplasia verruciformis

The DNAs of the human papillomaviruses (HPVs) associated with the benign lesions of two patients suffering from epidermodysplasia verruciformis (patients JD and JK) were analyzed by using 12 restriction endonucleases. None of the restriction endonucleases were one-cut enzymes for the HPV DNA obtained from patient JD, referred to as the prototypical HPV-5, whereas five of them were one-cut enzymes for the DNA of the major virus found in patient JK, referred to as HPV-9. The molecular cloning of the two fragments resulting from the cleavage of HPV-5 DNA by endonuclease HindIII and of the single fragment obtained after treatment of HPV-9 DNA with endonuclease BamHI was performed in Escherichia coli after the fragments were inserted in plasmid pBR322. A cleavage map of the two cloned genomes was constructed. Little sequence homology (4 to 5%) was detected between HPV-5 and HPV-9 DNAs by DNA-DNA hybridization experiments in liquid phase at saturation; this homology was reproducibly higher than that (2 to 3%) detected under the same conditions between these DNAs and HPV-1a DNA. In addition, blot hybridization experiments performed under stringent conditions showed no or little sequence homology between the DNAs of HPV-5 and HPV-9 and those of HPV prototypes of types 1, 2, 3, 4, and 7 associated with skin warts. These results confirm that HPV-5 and HPV-9 are two distinct HPV types.

Frequency and distribution of papillomavirus structural antigens in verrucae, multiple papillomas, and condylomata of the oral cavity

Sixty-seven proliferous squamous epithelial lesions of the oral cavity were examined for the presence of human papillomavirus whole (structural) virion antigens by a peroxidase-antiperoxidase technique having immunospecificity against genus-specific (common) antigens of the papillomaviruses. A positive reaction for papillomavirus genus specific antigens was found in 18 of 29 verrucae, 2 of 5 multiple papillomas, and 3 of 5 condylomata; common antigens were not detected in 28 keratoacanthomas. The positive reaction was invariably intranuclear in cells having a focal or diffuse distribution in the superficial epithelium. This study shows that a variety of squamous epithelial lesions of the mucosa are associated with human papillomaviruses and suggests that these viruses may play an important role in the etiology of some cases of squamous hyperplasia of the oral cavity.

Correlation between human papillomavirus (HPV) type and histology of warts

Forty warts from different patients and of different clinical type were examined histologically and virologically. Eight lesions were found to be associated with human papillomavirus type 1 (HPV 1), 15 tumors were induced by HPV 2, HPV 3 was detected 4 times, HPV 4 twice, and HPV 6 eleven times. HPV 3, HPV 4, and HPV 6 induced warts revealed a correlation between histology and virus type. They are characterized by the so called "edematous type clear cells". In HPV 3 associated flat warts pycnotic nuclei were mainly localized in the center of large vacuoles. In genital warts sickle shaped nuclei were pushed to the margin of the vacuolized cells. The histology of HPV 1 and HPV 2 induced warts was more heterogenous. With one exception HPV 1-induced lesions represented typical myrmecia warts, varying in the number and shape of inclusion bodies. HPV 2 associated common warts, however, revealed 3 very distinct histologic features: (1) Inclusion wart typical for HPV 1, (2) Classical common wart with marked condensation of keratohyalin granules, (3) Warts with extreme vacuolization of squamous and granular cells leading to a honeycomb-like picture.

Two anatomoclinical types of warts with plantar localization: specific cytopathogenic effects of papillomavirus. Type I (HPV-1) and type 2 (HPV-2)

In this study, the clinical and histopathological aspects of 50 plantar warts are reported in relation to the type of papillomavirus present in the lesions, as detected by immunofluorescence tests, using specific guinea pig fluorescein-labelled IgG. Warts of plantar localization are not caused by the same human papillomavirus (HPV) since they are found to be associated with both HPV type 1 (HPV-1) and HPV type 2 (HPV-2). HPV-1 is always associated with deep and painful plantar warts (myrmecia), whereas HPV-2 is found to be associated with superficial, painless plantar warts (vulgaris or often mosaic type). Histologically, these two types of plantar warts are quite different. In myrmecia (HPV-1), characterized by an endophytic growth, large eosinophilic, keratohyaline-like granules are observed in the cytoplasm and nucleus of infected, often vacuolated cells. These granules appear early in stratum spinosum and are very numerous in stratum granulosum. In the mosaic type (HPV-2), the histopathological aspect is not different from that of common warts; these lesions have an exophytic growth and are characterized by foci of clear vacuolized cells which are found in stratum granulosum. Their cytoplasm contains round, basophilic keratohyalin granules which often have a heterogenous aspect. These differences are observed in other localizations of morphologically related warts associated with HPV-1 and HPV-2 and seem to be related to a specific cytopathogenic effect of HPV-1 an HPV-2 in human papillomas.

Partial characterization of viral DNA from human genital warts (Condylomata acuminata)

By centrifuging total cellular DNA derived from human genital warts (condylomata acuminata) in CsCl-ethidium bromide gradients, supercoiled DNA was isolated. The molecular weight of this DNA was determined by agarose gel electrophoresis and amounted to 5.1 X 10(4). This DNA isolated from an individual genital wart was annealed to fractions of aqueous supernatants of the same wart after prior centrifugation of this material in CsCl density gradients. Annealing was observed at a density of approximately 1.32 g/ml corresponding to the expected density of papilloma virus particles. Since such particles were also observed in the same preparation by electron microscopy, it was concluded that the supercoiled DNA molecules were derived from papilloma virus nucleocapsids. Positive hybridization was found with six additional preparations from individual genital warts. Therefore, it seems that the isolated DNA prevails in condylomata acuminata. The DNA is different from the other five types of human papilloma viruses described thus far in regard to its restriction endonuclease cleavage patterns. The virus analyzed is tentatively designated as human papilloma virus type 6 (HPV 6).

Immunology of human warts

Rapid advances have occurred in the characterization of human papilloma virus (HPV) types applying the new advanced techniques of restriction endonuclease analysis and molecular hybridization to human wart virus. Human papilloma virus can no longer be viewed as a single, homogeneous virus producing all varieties of clinical warts. At least three antigenically heterogeneous HPV types have been associated with common and plantar warts. Two additional HPV types have been found in patients with epidermodysplasia verruciformis. Condylomata acuminata and laryngeal papillomas contain viruses which are also distinct from the preceding viruses and may represent additional HPV types. This antigenic heterogeneity of HPV has important implications concerning the immunology of human warts which have not been taken into account in most previously published studies. Both antibody and cell-mediated responses may be seen in patients with active warts, but many patients with warts have no demonstrable immune reactions. The role of immunity in wart regression remains poorly understood. Nevertheless, the increased frequency of warts in patients receiving immunosuppressive drugs and with immune deficiency states and the immunologic alterations which occur in patients with regressing or cured warts compared to patients with active warts, particularly the increased frequency of cell-mediated responses and antibodies specific for viral antigens, support a possible role for immunity in the resolution of warts. The evidence to date, however, does not prove that immune mechanisms are directly responsible for the elimination of warts.

The occurrence of human wart-virus antibodies in dogs, pigs and cattle

Using the immunodiffusion method, antibodies against human wart-virus were detected in dog, pig and cattle sera but not in horse and reindeer sera. Antibodies were found in 25 percent (28/114) of the dog sera, the prevalence of antibodies being fairly similar to that in children of the same age. By electron microscopy the antibodies in dog sera were shown to attach to and precipitate the human wart-virus particles, and in immunodiffusion the precipitation lines of human and dog sera were shown to be identical. Of the cattle sera studied, 10 percent (10/97) and of the pig sera 13 percent (5/40) gave a faint precipitation line, having identity with that given by the human sera, against human wart-virus. Conversely 18 percent (9/50) of adult human sera contained precipitating antibodies against a bovine papilloma antigen, probably bovine papilloma virus.