Immunologic responses following administration of a vaccine targeting human papillomavirus Types 6, 11, 16, and 18

Lack of effects on male fertility from a quadrivalent HPV vaccine in Sprague-Dawley rats

BACKGROUND

Human papillomavirus (HPV) infection is one of the most common sexually transmitted diseases in both men and women. A recently developed quadrivalent HPV vaccine, Gardasil, has been shown to be highly effective in the prevention of several HPV-mediated diseases. The objective of the present study was to evaluate the potential effects of the vaccine on male fertility including reproductive performance, sperm evaluations, and histology of the testes. In addition, anti-HPV antibodies were measured during the study.

METHODS

Group 1 (30 male rats) received the full human dose of vaccine (0.5 mL, ∼200-fold excess based on body weight) by intramuscular injection at 6 weeks, 3 weeks, and 3 days prior to cohabitation. Group 2 males received only 1 dose at 3 days prior to cohabitation. Additional groups (20 male rats each) were administered PBS or Merck Aluminum Adjuvant similarly to Group 1. Ten males in the vaccine-treated groups were bled for immunogenicity assays after each dose. Twenty males per group were mated to untreated female rats. Cesarean sections were performed on Gestation Day 15 or 16. Cohabited males were necropsied and sperm count and motility were evaluated.

RESULTS

There were no unscheduled deaths during the study and no evidence of toxicity in vaccine-treated male rats. The vaccine induced a specific antibody response to the 4 HPV types after each injection. There were no effects on the cesarean-section parameters of females or reproductive parameters of the cohabited male rats, including histomorphology of testes and epididymis, sperm count, and sperm motility.

CONCLUSIONS

These results demonstrate that this quadrivalent HPV vaccine had no detectable adverse effects on routine measures of male fertility in rats.

[Prophylactic and therapeutic vaccines against human papilloma virus]

Infection with human papilloma virus (HPV) has been identified as the cause of recurrent papillomatosis and of a subgroup of squamous cell carcinomas of the head and neck. A change in prevalence of these lesions, especially for oropharyngeal carcinoma, can be expected as a consequence of the introduction of prophylactic HPV vaccines for young women, targeting the most frequent high- and low-risk HPV subtypes. Vaccination for the major low-risk HPV types has proven to be highly effective against genital warts and activity against papillomatosis can be expected. The possibilities of prophylactic HPV vaccination as well as new developments and the rationale for therapeutic vaccines are discussed on the basis of the current literature.

Human papillomavirus 16 (HPV 16) and HPV 18 antibody responses measured by pseudovirus neutralization and competitive Luminex assays in a two- versus three-dose HPV vaccine trial

Human papillomavirus 16 (HPV 16) and HPV 18 antibody responses in a 2- versus 3-dose HPV vaccine (Gardasil) trial were measured by a pseudovirus neutralizing antibody (PsV NAb) assay and by the Merck competitive Luminex immunoassay (cLIA). Eight hundred twenty-four female subjects assigned to three dosing regimens (group 1, 9 to 13 years old; 2 doses, months 0 and 6 [n = 259]; group 2, 9 to 13 years old; 3 doses, months 0, 2, and 6 [n = 260]; group 3, 16 to 26 years old; 3 doses, months 0, 2, and 6 [n = 305]) had postvaccine responses assessed 1 month after the last dose. Of 791 subjects with baseline and 7-month sera, 15 (1.9%) and 9 (1.1%) were baseline seropositive for HPV 16 and HPV 18, respectively. All baseline-seronegative vaccinees seroconverted to both HPV 16 and HPV 18. Mean anti-HPV 16 levels were similar for groups 1 and 2 (for PsV NAb, P = 0.675; for cLIA, P = 0.874), and levels for both groups 1 and 2 were approximately 2-fold higher than that for group 3 (for PsV NAb and cLIA, P < 0.001). Mean anti-HPV 18 levels were approximately 1.4-fold lower in group 1 than in group 2 (for PsV, NAb P = 0.013; for cLIA, P = 0.001), and levels for both groups 1 and 2 were approximately 2.0- to 2.5-fold higher than that for group 3 (for PsV NAb and cLIA, P < 0.001). Pearson correlation coefficients for the assays were 0.672 for HPV 16 and 0.905 for HPV 18. Most of the discordant results were observed at lower cLIA signals. These results suggest that the PsV NAb assay could be a suitable alternative to cLIA for the measurement of postvaccine antibody responses.

Human papillomavirus infection in Honduran women with cervical intraepithelial neoplasia or cervical cancer

OBJECTIVES

The aims of this study were to investigate human papillomavirus (HPV) genotypes in women with cervical intraepithelial lesions and cervical cancer (CC) in Honduras and to identify epidemiological cofactors that contribute to the development of CC.

METHODS

Among the 289 patients analyzed, 139 had low-grade squamous intraepithelial lesion (LSIL), 60 had high-grade squamous intraepithelial lesion (HSIL), and 90 had CC.

RESULTS

The HPV DNA was detected in 113 women (81%) with LSIL, in 58 women (97%) with HSIL, and in 84 women (93%) with CC. Twenty-five HPV genotypes were found. Human papillomavirus type 16 was detected in 41% of women with CC, in 35% of women with HSIL, and in 24% of women with LSIL. Human papillomavirus type 18 was found in 9% of women with CC, in 4% of women with HSIL, and 5% of women with LSIL.

CONCLUSION

Therefore, implementation of the prophylactic vaccines against HPV genotypes 16 and 18 has the potential of preventing at least a quarter of LSIL, one third of HSIL, and about half of CC cases in Honduras.

HPV prophylactic vaccination: The first years and what to expect from now

New prophylactic HPV vaccines have the power to prevent many HPV infections, thus reducing the burden of HPV-associated diseases. Two vaccines composed of HPV L1 proteins self assembled into virus-like particles (VLPs) have been developed: one containing VLPS of HPV types 6, 11, 16 and 18, while the other vaccine is composed of HPV 16 and 18 VLPs. Large phase II and III clinical trials to assess prophylactic efficacy have been conducted in which both HPV infection endpoints and disease endpoints were evaluated, particularly high-grade cervical intraepithelial neoplasia--CIN2 or CIN3--as well as vulvar and vaginal intraepithelial neoplasias--VIN or VaIN--and genital warts for the quadrivalent vaccine. Very high efficacy rates were observed in different populations that included young women between 16 and 26 years of age, and older (up to 55). More recently, the quadrivalent vaccine has been shown to be efficacious in men to prevent genital and anal infection and disease caused by the types included in the vaccine. Based on demonstrated clinical efficacy and favorable safety profile, HPV prophylactic vaccine are being introduced worldwide aiming the reduction of the morbidity and mortality of tumors caused by HPV. From 2006 when first approved in the USA, hundreds of countries have licensed the HPV vaccines, a significant proportion of which are offering the vaccine to young women in national immunization programs supported by the government. The ultimate goal is to implement worldwide cervical cancer control programs to include HPV vaccination and screening with cytology and HPV DNA testing, particularly in less-developed countries where it is most needed.

Review of Gardasil

Human papillomavirus (HPV) is necessary for the development of cervical cancer. Cervical cancer is the second most common cancer in women worldwide but 80% occurs in developing countries, not countries with Pap screening programs. Pap screening programs in industrialized countries have reduced the incidence of cervical cancer to 4-8/100,000 women. HPV vaccines may be a promising strategy for cervical cancer in women without access to screening programs. In industrialized countries, the benefit of HPV vaccines focuses on individual abnormal Pap test reduction not cancer prevention. The focus of this review is to cover the side effects of Gardasil in perspective with the limited population benefit cervical cancer reduction in countries with organized Pap screening programs. In addition, information about Gardasil benefits, risks and unknowns for individual patient decision making for vaccination is presented. Gardasil offers protection against CIN 2+ lesions caused by HPV 16/18 and against genital warts caused by HPV 6/11 for at least 5 years. Combining Gardasil with repeated cytology screenings may reduce the proportion of abnormal cytology screens and hence reduce the associated morbidity with the subsequent colposcopies and excisional procedures.

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.

HPV vaccine: an overview of immune response, clinical protection, and new approaches for the future

Although long-term protection is a key-point in evaluating HPV-vaccine over time, there is currently inadequate information on the duration of HPV vaccine-induced immunity and on the mechanisms related to the activation of immune-memory. Longer-term surveillance in a vaccinated population is needed to identify waning immunity, evaluating any requirements for booster immunizations to assess vaccine efficacy against HPV-diseases. Current prophylactic vaccines have the primary end-points to protect against HPV-16 and 18, the genotypes more associated to cervical cancer worldwide. Nevertheless, data from many countries demonstrate the presence, at significant levels, of HPVs that are not included in the currently available vaccine preparations, indicating that these vaccines could be less effective in a particular area of the world. The development of vaccines covering a larger number of HPVs presents the most complex challenge for the future. Therefore, long term immunization and cross-protection of HPV vaccines will be discussed in light of new approaches for the future.

Therapeutic HPV DNA vaccines

It is now well established that most cervical cancers are causally associated with HPV infection. This realization has led to efforts to control HPV-associated malignancy through prevention or treatment of HPV infection. Currently, commercially available HPV vaccines are not designed to control established HPV infection and associated premalignant and malignant lesions. To treat and eradicate pre-existing HPV infections and associated lesions which remain prevalent in the U.S. and worldwide, effective therapeutic HPV vaccines are needed. DNA vaccination has emerged as a particularly promising form of therapeutic HPV vaccines due to its safety, stability and ability to induce antigen-specific immunity. This review focuses on improving the potency of therapeutic HPV vaccines through modification of dendritic cells (DCs) by [1] increasing the number of antigen-expressing/antigen-loaded DCs, [2] improving HPV antigen expression, processing and presentation in DCs, and [3] enhancing DC and T cell interaction. Continued improvement in therapeutic HPV DNA vaccines may ultimately lead to an effective DNA vaccine for the treatment of HPV-associated malignancies.

Evaluation of a liquid bead array system for high-risk human papillomavirus detection and genotyping in comparison with Hybrid Capture II, DNA chip and sequencing methods

Since persistent infection with high-risk human papillomavirus (HPV) is a known cause of high-grade cervical intraepithelial neoplasia and cervical cancer, several HPV DNA detection methods have been developed during the last decade. The Hybrid Capture II (HCII) assay, which allows detection of 13 high-risk HPVs, has been well validated; however, it does not provide any genotype-specific information. The oncogenic activity of HPV is dependent on its genotype. The prophylactic effects of HPV vaccines are based on L1 virus-like particles and are limited mainly to infections corresponding to the HPV type used to develop the immunogen. Therefore, accurate detection and genotyping are important for treatment as well as screening. A newly developed HPV genotyping system using a liquid bead array was evaluated with 286 cervical samples and the results were compared to two commercially available methods, i.e. the HCII and HPV DNA chip assays, and sequencing. The sensitivity for detection of high-risk HPV was 85.3 % (HCII), 94.7 % (DNA chip) and 99.0 % (liquid bead array). The liquid bead array showed almost perfect agreement (κ=0.95) with genotype information confirmed by sequencing, while substantial agreement (κ=0.8) was observed between DNA chip and sequencing. Furthermore, the liquid bead array had superior detection of 26 HPVs (16 high-risk and 10 low-risk types) and has proven to be as accurate as sequencing in identifying individual HPV types, even in cases with multiple HPV infections.

HPV - immune response to infection and vaccination

HPV infection in the genital tract is common in young sexually active individuals, the majority of whom clear the infection without overt clinical disease. However most of those who develop benign lesions eventually mount an effective cell mediated immune (CMI) response and the lesions regress.

Failure to develop effective CMI to clear or control infection results in persistent infection and, in the case of the oncogenic HPVs, an increased probability of progression to CIN3 and invasive carcinoma. The prolonged duration of infection associated with HPV seems to be associated with effective evasion of innate immunity thus delaying the activation of adaptive immunity.

Natural infections in animals show that neutralising antibody to the virus coat protein L1 is protective suggesting that this would be an effective prophylactic vaccine strategy. The current prophylactic HPV VLP vaccines are delivered i.m. circumventing the intra-epithelial immune evasion strategies. These vaccines generate high levels of antibody and both serological and B cell memory as evidenced by persistence of antibody and robust recall responses. However there is no immune correlate - no antibody level that correlates with protection. Recent data on how HPV infects basal epithelial cells and how antibody can prevent this provides a mechanistic explanation for the effectiveness of HPV VLP vaccines.

Women's knowledge of Pap smear test and human papillomavirus: acceptance of HPV vaccination to themselves and their daughters in an Islamic society

OBJECTIVE

Cancer of cervix uteri is the second most common cancer among women, and it has been shown to be caused by human papillomavirus (HPV) infection in more than 99% of cases. We surveyed Muslim Turkish women, who mostly accept talking about sex as a taboo, to examine their knowledge about Papanicolaou (Pap) smear test, HPV, HPV vaccine, and their attitude toward vaccination to themselves and their daughters.

METHODS

We surveyed 525 women aged between 19 and 53 years to examine their knowledge about cervical cancer screening Pap smear test, HPV, HPV vaccine, and their attitude toward vaccination to themselves and their daughters with a questionnaire that is consisted of 5 parts with a total of 31 items.

RESULTS

The knowledge of cervical screening was high (70%), and 51% of the subjects were at least once had a Pap smear test, but most respondents (56%) had never heard of HPV. For most women, recommendations from health workers (67%) were the major influences in deciding to get vaccinated.

CONCLUSIONS

The importance of successful introduction on the vaccine by the drug providers and health care professionals in Turkey was shown in this present study with a high rate of awareness of cervical cancer vaccine. "Early-age vaccination knowledge" before any sexual contact is probably due to the correct education of mothers by health care professionals. The professionals should be educated and trained about HPV, vaccination, and its relation with cervical cancer to increase the knowledge about it.

Prevalence of human papilloma virus infections and cervical cytological abnormalities among Korean women with systemic lupus erythematosus

We performed a multicenter cross-sectional study of 134 sexually active systemic lupus erythematosus (SLE) patients to investigate the prevalence of and risk factors for high risk human papilloma virus (HPV) infection and cervical cytological abnormalities among Korean women with SLE. In this multicenter cross-sectional study, HPV testing and routine cervical cytologic examination was performed. HPV was typed using a hybrid method or the polymerase chain reaction. Data on 4,595 healthy women were used for comparison. SLE patients had greater prevalence of high-risk HPV infection (24.6% vs. 7.9%, P<0.001, odds ratio 3.8, 95% confidence interval 2.5-5.7) and of abnormal cervical cytology (16.4 vs. 2.8%, P<0.001, OR 4.4, 95% CI 2.5-7.8) compared with controls. SLE itself was identified as independent risk factors for high risk HPV infection among Korean women (OR 3.8, 95% CI 2.5-5.7) along with ≥2 sexual partners (OR 8.5, 95% CI 1.2-61.6), and Pap smear abnormalities (OR 97.3, 95% CI 6.5-1,456.7). High-risk HPV infection and cervical cytological abnormalities were more common among Korean women with SLE than controls. SLE itself may be a risk factor for HPV infection among Korean women, suggesting the importance of close monitoring of HPV infections and abnormal Pap smears in SLE patients.

Human papillomavirus vaccines: current status and future prospects

Worldwide, cervical cancer is the second most common cancer of women. Less-developed countries bear the greatest burden in terms of morbidity and mortality, largely due to the lack of organized screening programmes. Cervical cancer is the first cancer shown to be caused solely by virological agents: oncogenic genotypes of human papillomavirus (HPV). Two recently developed prophylactic cervical cancer vaccines, which are based on viral-like particle (VLP) technology of HPV, have the capacity to diminish a large proportion of cervical cancer cases worldwide. However, to be successful public health tools, they need to be widely implemented to the appropriate target population, preferably prior to first sexual intercourse. To increase vaccination coverage, national programmes in some countries have also included catch-up vaccination, for a limited time period, to young adult women aged up to 26 years. Despite the excellent efficacy for high-grade dysplasia due to vaccine-related HPV types (near to 100%) and immunogenicity induced against the HPV types 16 and 18 in females naive to those HPV types pre-vaccination, some form of cervical precancer screening will still be necessary. Immunity to HPV is primarily type specific, and thus protection induced by the current generation of vaccines, based on a limited number of HPV VLP types, cannot provide complete protection against all oncogenic HPV types. Both these vaccines translate to protection of cervical cancer in the order of 70-75%, which represents the percentage of invasive cancers attributable to HPV-16 and -18. Challenges to ensuring the successful control of this largely preventable disease include endorsement by governments and policy makers, affordable prices, education at all levels, overcoming barriers to vaccination and continued adherence to screening programmes.

Prevention of cervical, vaginal, and vulval cancers: role of the quadrivalent human papillomavirus (6, 11, 16, 18) recombinant vaccine

The relationship between the human papillomavirus (HPV) and malignancies of the uterine cervix, vagina, and vulva has been established. The development of a quadrivalent HPV recombinant prophylactic vaccine represents the first time in history that primary prevention of these cancers is offered to girls and women. The prevalence of oncogenic HPV subtypes in cervical cancers has been the most studied, but prevalence has also been established for vaginal and vulvar cancers. Clinical trials demonstrate impressive efficacy in disease prevention as well as excellent safety and tolerability. The role the quadrivalent HPV recombinant vaccine promises to have in the reduction of gynecologic malignancies will depend on various factors, including acceptance and accessibility of the vaccine, duration of immunity, and cross-protection against other oncogenic HPV subtypes. The HPV vaccine's role in disease reduction will probably be viewed in the context of a strategy that involves continued secondary screening and lifestyle modification to reduce modifiable risk factors, along with widespread vaccination.

Are women with lupus at higher risk of HPV infection?

Human papillomavirus (HPV) is the etiological agent of cervical cancer, the second most prevalent neoplasia among women. Although it has been proven that systemic lupus erythematosus (SLE) patients have higher frequency of cervical dysplasia, few studies have focused on HPV prevalence among them. This study aimed to investigate HPV prevalence among SLE patients and to evaluate associated risk factors, including the use of immunosuppressors (IM). Total DNA extracted from cervical samples of 173 SLE patients and 217 women (control group) submitted to routine cervical cytopathology was used as template in polymerase chain reaction (PCR)-based assays for detection of HPV DNA. HPV genotyping was performed by type-specific PCR, PCR-RFLP and/or DNA sequencing. Statistical methods included univariate analysis and logistic regression. Despite presenting significantly fewer HPV risk factors, SLE patients were found to have a threefold increase in HPV infection, mostly genotypes 53, 58, 45, 66, 6, 84, 83, 61, as compared with controls, who presented types 6, 18 and 61 more frequently. The higher rate of HPV infection was associated with immunosuppressive therapy. This study provides evidence that SLE patients have a high prevalence of HPV infection, which is even higher with the use of IM, a condition that might necessitate a more frequent cervical cancer screening program for these women.

High-throughput profiling of the humoral immune responses against thirteen human papillomavirus types by proteome microarrays

We have developed microarrays with all eight proteins encoded by 13 different human papillomavirus types associated with anogenital cancer (HPV-16, -18, -31, -33, -35, -45, and -53), genital warts (HPV-6 and -11), or skin lesions (HPV-1, -2, -4, and -5). We analyzed the seroprevalence of antibodies in 546 patients, which had either cervical carcinomas, or precursor lesions, or which were asymptomatic. All patient groups contained sera ranging from high reactivity against multiple HPV proteins to low or no reactivity. Computational analyses showed the E7 proteins of carcinogenic HPV types as significantly more reactive in cancer patients compared to asymptomatic individuals and discriminating between cancer and HSIL or LSIL patients. Antibodies against E4 and E5 had the highest seroprevalence but did not exhibit differential reactivity relative to pathology. Our study introduces a new approach to future evaluation of the overall antigenicity of HPV proteins and cross-reaction between homologous proteins.

Understanding differences in predictions of HPV vaccine effectiveness: A comparative model-based analysis

Mathematical models of HPV vaccine effectiveness and cost-effectiveness have produced conflicting results. The aim of this study was to use mathematical models to compare and isolate the impact of the assumptions most commonly made when modeling the effectiveness of HPV vaccines. Our results clearly show that differences in how we model natural immunity, herd immunity, partnership duration, HPV types, and waning of vaccine protection lead to important differences in the predicted effectiveness of HPV vaccines. These results are important and useful to assist modelers/health economists in choosing the appropriate level of complexity to include in their models, provide epidemiologists with insight on key data necessary to increase the robustness of model predictions, and help decision makers better understand the reasons underlying conflicting results from HPV models.

Human papillomavirus vaccine update

With the approval of Gardasil (Merck and Co., Inc., Whitehouse Station, NJ) in June of 2006 and the pending approval of Cervarix (GlaxoSmithKline, London, UK), two prophylactic human papillomavirus (HPV) vaccines will be available for clinical use. Randomized controlled trials have shown that both vaccines are safe and highly effective in preventing persistent infection and lesions caused by HPV 16 and 18--the types responsible for 70% of cervical cancers worldwide. Determining an effective vaccination strategy is now the most pressing issue facing clinicians, parents, public health officials, and policy makers. We discuss the appropriate age of vaccination, vaccine acceptance, implementation strategies in low resource settings, and the future of screening.

Multiplexed serologic assay for nine anogenital human papillomavirus types

A multiplexed human papillomavirus (HPV) immunoassay has been developed for the detection of human IgG antibodies to HPV type 6, 11, 16, 18, 31, 33, 45, 52, and 58 virus-like particle (VLP) types in serum following natural infection or immunization with VLP-based vaccines. The VLP antigens were covalently conjugated to carboxyl Luminex microspheres (MS) using a carbodiimide chemistry. Antibody (Ab) titers were determined in a direct binding format, in which an IgG1- to -4-specific, phycoerythrin (PE)-labeled monoclonal antibody (MAb) (HP6043) binds to human serum IgG antibodies. Pooled serum samples from rhesus macaques immunized with a 9-valent VLP-based vaccine served as the reference standard. The overall specificity of the assay was >99%, and the linearity (parallelism) of the assay was <7% per 10-fold dilution. Total assay precision was <19% across 3 different VLP-microsphere lots, 2 secondary antibody lots, and 2 different operators over a period of 3 weeks. Three different methods were used to evaluate serostatus cutoffs (SCO): (i) a clinical sensitivity/specificity analysis based on "likely negative" and "likely positive" samples from nonvaccinees, (ii) stringent upper tolerance limits on samples from "likely negatives," and (iii) stringent upper tolerance limits from the same "likely negative" sample set after VLP adsorption. Depending on the method to set the serostatus cutoff, the percentage of seropositive samples at the month 48 time point following vaccination with the HPV 6/11/16/18 quadrivalent vaccine ranged from 70% to 100%. This assay has proven useful for measuring the levels of serum antibody to the nine HPV VLPs following natural infection or administration of VLP-based vaccines.

Prophylactic human papillomavirus vaccines: will they do their job?

The prophylactic HPV L1 virus like particle vaccines are highly efficacious preventing >98% of HPV 16/18 caused high grade cervical intra-epithelial neoplasia (CIN2/3) according to protocol group in phase III randomized clinical trials over approximately 4 years. Data from the trials together with postvaccine surveillance indicates that they have a good safety profile. As the current HPV vaccines include only two of the 15 oncogenic HPVs, they will not eliminate cervical cancer or the other HPV associated ano-genital diseases but could reduce, for example, the incidence of cervix cancer by up to 70-80%, if effectively delivered to adolescent females.

Perspectives for preventive and therapeutic HPV vaccines

Human Papillomavirus (HPV) has been associated with several human cancers, including cervical cancer, vulvar cancer, vaginal and anal cancer, and a subset of head and neck cancers. Thus effective vaccination against HPV provides an opportunity to reduce the morbidity and mortality associated with HPV. The Food and Drug Administration of the United States has approved two preventive vaccines to limit the spread of HPV. However, these are unlikely to impact upon HPV prevalence and cervical cancer rates for many years. Furthermore, preventive vaccines do not exert therapeutic effects on pre-existing HPV infections and HPV-associated lesions. In order to further impact upon the burden of HPV infections worldwide, therapeutic vaccines are being developed. These vaccines aim to generate a cell-mediated immune response to infected cells. This review discusses current preventive and therapeutic HPV vaccines and their future directions.

Efficacy of human papillomavirus vaccines: a systematic quantitative review

Human papillomavirus (HPV) types cause approximately 70% of cervical cancer worldwide. Two vaccines have been recently evaluated in randomized controlled trials: the bivalent vaccine for HPV 16 and 18 (Cervarix, GlaxoSmithKline Biologicals, Rixensart, Belgium) and the quadrivalent vaccine for HPV 6, 11, 16, and 18 (Gardasil, Merck and Co, Inc, Whitehouse Station, NJ). We have performed a systematic review of all randomized controlled trials in which vaccines against HPV were compared with placebo regarding efficacy, safety, and immunogenicity. Six studies met the inclusion criteria, which included 47,236 women. The first objective in this systematic review was to assess vaccine efficacy in the prevention of cytologically and/or histologically proven lesions. And the secondary objective was the evaluation of safety and vaccine immunogenicity. Bivalent and quadrivalent HPV vaccines significantly reduced the rate of lesions in the cervix, vulva, vagina, and anogenital region, with efficacy of 93% (95% confidence interval [CI], 87-96) and 62% (95% CI, 27-70), respectively, when compared with the control groups according to intention to treat. Regarding safety, we found more symptoms in the bivalent vaccine group (35%; 95% CI, 5-73) when compared with the control groups. In regard to vaccine immunogenicity, there was seroconversion in the group that received the vaccine when compared with the placebo group in the bivalent and quadrivalent vaccines. Prophylactic vaccination can prevent HPV infection in women aged 9 to 26 years not previously infected with the HPV subtypes covered by the vaccines. To evaluate cervical cancer incidence and mortality, a longer follow-up is necessary.

Human papillomavirus vaccination in the prevention of cervical neoplasia

Cervical cancer remains a major cause of morbidity and mortality for women worldwide. Although the introduction of comprehensive screening programs has reduced the disease incidence in developed countries, it remains a major problem in the developing world. The recent licensing of 2 vaccines against human papillomavirus (HPV) type 16 and HPV-18, the viruses responsible for 70% of cervical cancer cases, offers the hope of disease prevention. In this article, we review the role of HPV in the etiology of cervical cancer and the evidence to support the introduction of vaccination programs in young women and discuss the potential obstacles to widespread vaccination. In addition, we discuss the issues that remain to be elucidated, including the potential need for booster doses of the vaccine and the role of concomitant vaccination in men.

Antibody responses in oral fluid after administration of prophylactic human papillomavirus vaccines

We sought to determine whether oral fluid can be used to assess serum human papillomavirus (HPV) antibody status by enrolling women who had received a prophylactic HPV-16 vaccine in a new follow-up study. After the prophylactic HPV-6/11/16/18 vaccine was licensed in the United States, we administered it to consenting participants. With serologic findings used as the reference standard, The sensitivity of oral fluid was 49.6% (95% confidence interval [CI], 42.0%-57.3%) before and 100% (95% CI, 92.0%-100%) after administration of the quadrivalent vaccine. Oral fluid may have the potential to be used for monitoring of prophylactic HPV vaccines in the future.

EUROGIN 2008 roadmap on cervical cancer prevention

The EUROGIN 2008 Roadmap represents a continuing effort to provide updated information on primary and secondary prevention of cervical cancer. The report addresses several areas including the progress made toward global implementation of currently licensed human papillomavirus (HPV) vaccines, the possibilities and value of future-generation HPV vaccines, endpoints under consideration for evaluation of candidate HPV vaccines, and monitoring impact of HPV vaccination programmes that can be implemented within developed and less-developed countries. For the sake of completeness, a short update on the evolution of HPV testing in primary screening programmes at present and after HPV vaccine introduction has also been included. The report is available on the EUROGIN website (www.eurogin.com).

A nontoxic derivative of lipopolysaccharide increases immune responses to Gardasil HPV vaccine in mice

Human papillomavirus (HPV) is the causative agent of cervical cancer, the second most common cause of cancer death in women worldwide. The licensed HPV vaccine Gardasil((R)) from Merck & Co. is a quadrivalent vaccine containing virus-like particles (VLPs) of the L1 proteins from HPV types 6, 11, 16, and 18 adsorbed on aluminum salts (alum). CIA07 is an immunostimulatory agent comprised of bacterial DNA fragments (CIA02) and a nontoxic derivative of lipopolysaccharide (CIA05) that has been shown to have antitumor activity and adjuvant activity for viral and bacterial vaccine antigens. We investigated whether these CIAs are capable of promoting the immune response to Gardasil. Balb/c mice were immunized intramuscularly twice three weeks apart with 1/20 human dose of Gardasil alone or in combination with CIA02, CIA05 or both, and immune responses were assessed. The serum anti-HPV16 L1 VLP IgG antibody titer was significantly higher in mice administered CIA05 or CIA05 plus CIA02, but not in those given CIA02, compared with mice given Gardasil alone. A secreted alkaline phosphatase (SEAP)-based pseudovirus neutralization assay showed increased neutralizing antibody titers in both CIA05 and CIA05 plus CIA02 groups. Coadministration of CIA05 with Gardasil led to a marked increase in serum IgG2a antibody titer and the percentage of interferon (IFN)-gamma(+) cells in the spleen, indicating that CIA05 effectively promotes Th1-type immune responses. These data indicate that CIA05, in synergy with alum, enhances the immune response to HPV L1 VLPs and suggest its potential as an adjuvant for the development of a potent prophylactic HPV vaccine.

Therapeutic HPV DNA vaccines

Human papillomavirus (HPV) has been associated with several human cancers, including cervical cancer, vulvar cancer, vaginal and anal cancer, and a subset of head and neck cancers. The identification of HPV as an etiological factor for HPV-associated malignancies creates the opportunity for the control of these cancers through vaccination. Currently, the preventive HPV vaccine using HPV virus-like particles has been proven to be safe and highly effective. However, this preventive vaccine does not have therapeutic effects, and a significant number of people have established HPV infection and HPV-associated lesions. Therefore, it is necessary to develop therapeutic HPV vaccines to facilitate the control of HPV-associated malignancies and their precursor lesions. Among the various forms of therapeutic HPV vaccines, DNA vaccines have emerged as a potentially promising approach for vaccine development due to their safety profile, ease of preparation and stability. However, since DNA does not have the intrinsic ability to amplify or spread in transfected cells like viral vectors, DNA vaccines can have limited immunogenicity. Therefore, it is important to develop innovative strategies to improve DNA vaccine potency. Since dendritic cells (DCs) are key players in the generation of antigen-specific immune responses, it is important to develop innovative strategies to modify the properties of the DNA-transfected DCs. These strategies include increasing the number of antigen-expressing/antigen-loaded DCs, improving antigen processing and presentation in DCs, and enhancing the interaction between DCs and T cells. Many of the studies on DNA vaccines have been performed on preclinical models. Encouraging results from impressive preclinical studies have led to several clinical trials.

Vaccine adherence in adolescents

Although a number of routine and catch-up vaccinations are currently recommended for adolescents, coverage rates of these vaccines are currently suboptimal. Routine recommended immunizations for this cohort include vaccines for influenza, human papillomavirus, and meningococcal disease, as well as a booster for tetanus, diphtheria, and acellular pertussis. Adolescence is also a critical period for administration of catch-up vaccines for those not fully immunized during childhood. Adolescents who do not seek appropriate preventive healthcare are at risk for significant morbidity and possible mortality. Increasing adolescent adherence to recommended vaccine schedules presents a challenge and opportunity for pediatricians and public health advocates. This article outlines barriers to vaccine compliance among adolescents and discusses strategies to increase vaccine uptake.

Development of therapeutic HPV vaccines

At least 15% of human malignant diseases are attributable to the consequences of persistent viral or bacterial infection. Chronic infection with oncogenic human papillomavirus (HPV) types is a necessary, but insufficient, cause in the development of more cancers than any other virus. Currently available prophylactic vaccines have no therapeutic effect for established infection or for disease. Early disease is characterised by tissue sequestration. However, because a proportion of intraepithelial HPV-associated disease undergoes immune-mediated regression, the development of immunotherapeutic strategies is an opportunity to determine proof-of-principle for therapeutic vaccines. In this Review, we discuss recent progress in this field and priorities for future clinical investigations.

[HPV immunization for the prevention of cervical cancer]

CONTEXT

Human Papillomaviruses (HPV) infect epithelial cells of the skin and mucosae. Mucosal high-risk HPV types (mainly HPV 16 and 18) are involved in the development of cervical cancer, one of the most common cancers in young women. HPV infection is usually asymptomatic and clears spontaneously, but 10 - 15 % of high-risk HPV infections are persistent and increase the risk of precancerous and cancerous lesions of the cervix. Two HPV vaccines have been licensed to provide protection against cervical cancer.

OBJECTIVES

To report the different aspects of HPV infection in order to improve the understanding of the particular problems of HPV vaccination and to review the most recent findings related to HPV vaccines, particularly regarding the protective efficacy of vaccines and the roles of adjuvants and immune response in protection.

METHODS

Articles were selected from the PubMed database (National Library of Medicine- National Institute of Health) with the following Keywords "HPV", "Prevention", "HPV vaccines", "Immune response", "Antibody". Abstracts of oral presentations from international meetings were also selected for the more recent findings. a critical analysis of the majority of papers published was undertaken and relevant information summarized.

RESULTS

Virus-like particle production by expressing the major protein of the HPV capsid was carried out in the early 90's, leading to the recent development of two HPV vaccines. These vaccines are now licensed in many countries and have been demonstrated to be highly immunogenic. In subjects that are non-infected at the time of vaccination, HPV vaccines are highly effective in preventing persistent HPV 16 - 18 infections (90 %) and precursors lesions of cervical cancer associated with these two HPV types (close to 100 %). Clinical trials have also confirmed that HPV vaccines are well tolerated by recipients.

CONCLUSIONS

The present paper is a detailed review published in French on HPV vaccines, their efficacy in the prevention of HPV infections and unresolved questions regarding the use of HPV vaccines. This report also includes biological and immunological information to improve the understanding of HPV vaccination.

[Human papillomavirus and cervical neoplasia]

Human papillomavirus (HPV) has been established as an important etiological factor for the development of cervical cancer. This DNA virus primarily infects the epithelium and can induce benign and malignant lesions of the mucous membranes and skin. Some HPVs are considered high risk due to their role in malignant progression of cervical tumors. Genital HPV infections are common and usually transient among young sexually active women. Only a small fraction of infected women develop cervical cancer, implying the involvement of environmental and genetic cofactors in cervical carcinogenesis. Classification, virology, pathology, natural history, epidemiological features of genital HPV infection, and future prospects for cervical cancer prevention with HPV vaccines will be reviewed here.

Longer term efficacy of a prophylactic monovalent human papillomavirus type 16 vaccine

We conducted an extended follow-up study (March 2006-May 2008) to assess the longer term efficacy of a prophylactic monovalent human papillomavirus (HPV) type 16 L1 virus-like particle vaccine in women (n=290) who had enrolled in a randomized controlled trial of this vaccine (October 1998-November 1999) in Seattle and remained HPV-16 DNA negative during the course of that trial. During the extended follow-up period, in the per-protocol susceptible population, none of the vaccine recipients was found to be infected with HPV-16 or developed HPV-16-related cervical lesions; among placebo recipients, 6 women were found to be infected with HPV-16 (vaccine efficacy [VE]=100%; 95% confidence interval [CI]: 29-100%) and 3 women developed HPV-16-related cervical lesions (VE=100%; 95% CI: <0-100%). Approximately 86% of vaccine recipients remained HPV-16 competitive Luminex immunoassay seropositive at an average of 8.5 years of follow-up. During the combined original trial and extended follow-up period, in the intention-to-treat population, 20 and 22 women developed any cervical lesion regardless of HPV type among the vaccine and placebo recipients, respectively (VE=15%; 95% CI: <0-56%). The results suggest that this monovalent HPV-16 vaccine remains efficacious through 8.5 years after its administration.

Epidemiologic natural history and clinical management of Human Papillomavirus (HPV) Disease: a critical and systematic review of the literature in the development of an HPV dynamic transmission model

BACKGROUND

Natural history models of human papillomavirus (HPV) infection and disease have been used in a number of policy evaluations of technologies to prevent and screen for HPV disease (e.g., cervical cancer, anogenital warts), sometimes with wide variation in values for epidemiologic and clinical inputs. The objectives of this study are to: (1) Provide an updated critical and systematic review of the evidence base to support epidemiologic and clinical modeling of key HPV disease-related parameters in the context of an HPV multi-type disease transmission model which we have applied within a U.S. population context; (2) Identify areas where additional studies are particularly needed.

METHODS

Consistent with our and other prior HPV natural history models, the literature review was confined to cervical disease and genital warts. Between October 2005 and January 2006, data were gathered from the published English language medical literature through a search of the PubMed database and references were examined from prior HPV natural history models and review papers. Study design and data quality from individual studies were compared and analyses meeting pre-defined criteria were selected.

RESULTS

Published data meeting review eligibility criteria were most plentiful for natural history parameters relating to the progression and regression of cervical intraepithelial neoplasia (CIN) without HPV typing, and data concerning the natural history of HPV disease due to specific HPV types were often lacking. Epidemiologic evidence to support age-dependency in the risk of progression and regression of HPV disease was found to be weak, and an alternative hypothesis concerning the time-dependence of transition rates is explored. No data were found on the duration of immunity following HPV infection. In the area of clinical management, data were observed to be lacking on the proportion of clinically manifest anogenital warts that are treated and the proportion of cervical cancer cases that become symptomatic by stage.

CONCLUSION

Knowledge of the natural history of HPV disease has been considerably enhanced over the past two decades, through the publication of an increasing number of relevant studies. However, considerable opportunity remains for advancing our understanding of HPV natural history and the quality of associated models, particularly with respect to examining HPV age- and type-specific outcomes, and acquired immunity following infection.

[Nobel price for vaccination against cervical cancer: current data and guidelines]

Harald zur Hausen received the Nobel price for Medicine in 2008 for his seminal research on human papilloma viruses and their association with anogenital diseases. On the basis of his work highly effective prophylactic vaccines have been developed. Clinical studies have shown nearly 100% seroconversion and an excellent safety profile as well as greater than 96% efficacy against HPV infection and premalignant dysplasia, induced by HPV types covered by the vaccine. Due to the convincing data of phase II and III clinical trials the introduction of HPV vaccination was recommended by health authorities and scientific committees in Germany. The development and availability of guidelines and evidence-based recommendations should support the introduction of the vaccine and widespread vaccination.

Dynamics of human papillomavirus serology in women followed up for 36 months after pregnancy

We determined L1 antibodies for human papillomavirus (HPV) types 6, 11, 16, 18 and 45 by multiplex serology in our prospective HPV family study. We report seroprevalence, seroconversion and antibody decay in 290 women (mean age, 25.5 years) sampled before delivery and at 12, 24 and 36 months of follow-up. Multiplex HPV genotyping of the baseline oral and genital scrapings was performed. At baseline, seroprevalence of HPV 6, 11, 16, 18 and 45 was 53.3, 21.5, 34.9, 21.5 and 9.0 %, respectively. Seropositivity for low-risk HPV (LR-HPV) was associated significantly with age at onset of sexual activity (P=0.001), number of sexual partners until age 20 (P=0.018), lifetime number of sexual partners (P=0.0001), history of genital warts (P=0.0001) and being seropositive for high-risk (HR) HPV (P=0.0001). The same covariates also predicted seropositivity for HR-HPV. During follow-up, 26.7, 13.9, 17.0, 16.8 and 6.6 % of the women seroconverted to L1 antigen of HPV 6, 11, 16, 18 and 45, respectively, between 18.2 and 23.8 months. Independent predictors of seroconversion to LR-HPV were unemployment (P=0.019) and absence of anal sex practice (P=0.031), and to HR-HPV, absence of smoking history and lifetime number of sexual partners. Decay of HPV 6, 11, 16, 18 and 45 antibodies was observed in 2.3, 4.0, 5.3, 4.5 and 1.5 % of the women, respectively, with decay time varying from 27.2 to 35.8 months. These data imply that (i) a substantial proportion of young women are seropositive for both LR- and HR-HPV types, (ii) they frequently undergo seroconversion within 18–24 months, predicted by common covariates, and (iii) antibody decay over 3 years is rare.

Virus-like particle (VLP) lymphatic trafficking and immune response generation after immunization by different routes

Virus-like particles (VLPs) have gained increasing interest for their use as vaccines due to their repetitive antigenic structure that is capable of efficiently activating the immune system. The efficacy of VLP immunization may lie in its ability to traffic into draining lymph nodes while activating antigen-presenting cells to initiate the orchestration of signals required for the development of a robust immune response. Currently, there is no comprehensive study showing the correlation of different VLP vaccination routes to immune outcome. In this study, we took an optical imaging approach to directly visualize the trafficking of simian-human immunodeficiency (SHIV) VLPs after immunization by commonly used routes and analyzed the corresponding humoral and cellular immune responses generated. We found that VLPs can easily enter the subcapsular sinus of draining lymph nodes with quantitative differences in the number of lymph node involvement depending on the immunization route used. Intradermal immunization led to the largest level of lymph node involvement for the longest period of time, which correlated with the strongest humoral and cellular immune responses. Flow cytometry analysis from extracted splenocytes showed that intradermal immunization led to the largest population of germinal center and activated B cells, which translated into higher antibody levels and antigen-specific cytotoxic T lymphocyte responses. Our results indicate that VLPs traffic into lymph nodes upon immunization and can be directly visualized by optical imaging techniques. Intradermal immunization showed improved responses and might be a preferable delivery route to use for viral and cancer immunotherapeutic studies involving VLPs.

Factors associated with fluctuations in IgA and IgG levels at the cervix during the menstrual cycle

OBJECTIVE

The objective of this analysis was to describe patterns and determinants of cervical immunoglobulin A (IgA) and G (IgG) levels during the menstrual cycle.

METHODS

A total of 154 women who attended 3 visits coinciding with the follicular, periovulatory, and luteal phases of their menstrual cycle were studied. Cervical secretions were collected at each visit for determination of total IgA and IgG levels. Questionnaires administered at each visit inquired about demographic characteristics and behavioral practices.

RESULTS

Total IgA and IgG levels were higher among oral contraceptive (OC) users than among naturally cycling women (hereafter, "non-OC users"). IgA and IgG levels decreased at midcycle, particularly among non-OC users. After adjustment for phase of the current cycle, specimen weight, and detection of blood in the sample, report of a recent illness was associated with lower IgA and IgG levels and increased age with higher IgA and IgG levels among OC users and non-OC users. Increased lifetime number of pregnancies was associated with a higher IgA level among non-OC users and a higher IgG level among OC users. Change in immunoglobulin levels between visits was associated with sample weight and the presence of blood for both OC users and non-OC users.

CONCLUSIONS

Phase of the current menstrual cycle and OC use were significant determinants of cervical IgA and IgG levels. The impacts of endogenous and exogenous hormones on cervical immunoglobulin levels should be further investigated.

Human papillomavirus vaccine and cervical cancer prevention

Cervical cancer is one of the most common types of cancer in women worldwide, with the highest rates observed in underdeveloped countries. In the last decades, its incidence has decreased after the implementation of screening programs, mainly in developed countries. Infection with high-risk oncogenic HPV is associated with precancerous lesions and cervical cancer. Advances in the understanding of the role of HPV in the etiology of high-grade cervical lesions (CIN 2/3) and cervical cancer have led to the development, evaluation and recommendation of two prophylactic HPV vaccines. This review article provides a summary of the studies related with their development and efficacy.