Synergistic effects of exosomal crocin or curcumin compounds and HPV L1-E7 polypeptide vaccine construct on tumor eradication in C57BL/6 mouse model

Cervical cancer is the most common malignant tumor in females worldwide. Human papillomavirus (HPV) infection is associated with the occurrence of cervical cancer. Thus, developing an effective and low-cost vaccine against HPV infection, especially in developing countries is an important issue. In this study, a novel HPV L1-E7 fusion multiepitope construct designed by immunoinformatics tools was expressed in bacterial system. HEK-293T cells-derived exosomes were generated and characterized to use as a carrier for crocin and curcumin compounds. The exosomes loaded with crocin and curcumin compounds as a chemotherapeutic agent (ExoCrocin and ExoCurcumin) were used along with the L1-E7 polypeptide for evaluation of immunological and anti-tumor effects in C57BL/6 mouse model. In vitro studies showed that ExoCrocin and ExoCurcumin were not cytotoxic at a certain dose, and they could enter tumor cells. In vivo studies indicated that combination of the L1-E7 polypeptide with ExoCrocin or ExoCurcumin could produce a significant level of immunity directed toward Th1 response and CTL activity. These regimens showed the protective and therapeutic effects against tumor cells (the percentage of tumor-free mice: ~100%). In addition, both ExoCrocin and ExoCurcumin represented similar immunological and anti-tumor effects. Generally, the use of exosomal crocin or curcumin forms along with the L1-E7 polypeptide could significantly induce T-cell immune responses and eradicate tumor cells.

Designing a therapeutic and prophylactic candidate vaccine against human papillomavirus through vaccinomics approaches

OBJECTIVE

Human papillomavirus (HPV) is the main cause of cervical cancer, the 4^th prominent cause of death in women globally. Previous vaccine development projects have led to several approved prophylactic vaccines available commercially, all of which are made using major capsid-based (L1). Administration of minor capsid protein (L2) gave rise to the second generation investigational prophylactic HPV vaccines, none of which are approved yet due to low immunogenicity provided by the L2 capsid protein. On the other hand, post-translation proteins, E6 and E7, have been utilized to develop experimental therapeutic vaccines. Here, in silico designing of a therapeutic and prophylactic vaccine against HPV16 is performed.

METHODS

In this study, several immunoinformatic and computational tools were administered to identify and design a vaccine construct with dual prophylactic and therapeutic applications consisting of several epitope regions on L2, E6, and E7 proteins of HPV16.

RESULTS

Immunodominant epitope regions (aa 12-23 and 78-78 of L2 protein, aa 11-27 of E6 protein, and aa 70-89 of E7 protein) were employed, which offered adequate immunogenicity to induce immune responses. Resuscitation-promoting factors (RpfB and RpfE) of Mycobacterium tuberculosis were integrated in two separate constructs as TLR4 agonists to act as vaccine adjuvants. Following physiochemical and structural evaluations carried out by various bioinformatics tools, the designed constructs were modeled and validated, resulting in two 3D structures. Molecular docking and molecular dynamic simulations suggested stable ligand-receptor interactions between the designed construct and TLR4.

CONCLUSION

Ultimately, this study led to suggest the designed construct as a potential vaccine candidate with both prophylactic and therapeutic applications against HPV by promoting Th1, Th2, CTL, and B cell immune responses, which should be further confirmed in experimental studies.

Human Papillomavirus: Screening, Testing, and Prevention

With more than 200 types identified, human papillomavirus (HPV) commonly causes infections of the skin and mucosa. HPV infection is the most common sexually transmitted infection in the United States. Although most HPV infections are transient and subclinical, some lead to clinical manifestations ranging from benign papillomas or warts to intraepithelial lesions. In some patients, persistent infection with high-risk mucosal types, especially HPV-16 and HPV-18, causes anal, cervical, oropharyngeal, penile, vaginal, and vulvar cancers. Most HPV-related cancers are believed to be caused by sexual spread of the virus. A history of multiple sex partners; initiation of sexual activity at an early age; not using barrier protection; other sexually transmitted infections, including HIV; an immunocompromised state; alcohol use; and smoking have been identified as risk factors for persistent HPV infections. Screening for HPV infection is effective in identifying precancerous lesions and allows for interventions that can prevent the development of cancer. Use of condoms and dental dams may decrease spread of the virus. Vaccination is the primary method of prevention. The nonavalent HPV vaccine is effective in preventing the development of high-grade precancerous cervical lesions in noninfected patients. Vaccination is ideally administered at 11 or 12 years of age, irrespective of the patient's sex. In general, a two-dose series is recommended if administered before 15 years of age; however, individuals who are immunocompromised require three doses.

Characterization of recombinant gorilla adenovirus HPV therapeutic vaccine PRGN-2009

There are approximately 44,000 cases of human papillomavirus-associated (HPV-associated) cancer each year in the United States, most commonly caused by HPV types 16 and 18. Prophylactic vaccines successfully prevent healthy people from acquiring HPV infections via HPV-specific antibodies. In order to treat established HPV-associated malignancies, however, new therapies are necessary. Multiple recombinant gorilla adenovirus HPV vaccine constructs were evaluated in NSG-β2m-/- peripheral blood mononuclear cell-humanized mice bearing SiHa, a human HPV16+ cervical tumor, and/or in the syngeneic HPV16+ TC-1 model. PRGN-2009 is a therapeutic gorilla adenovirus HPV vaccine containing multiple cytotoxic T cell epitopes of the viral oncoproteins HPV 16/18 E6 and E7, including T cell enhancer agonist epitopes. PRGN-2009 treatment reduced tumor volume and increased CD8+ and CD4+ T cells in the tumor microenvironment of humanized mice bearing the human cervical tumor SiHa. PRGN-2009 monotherapy in the syngeneic TC-1 model also reduced tumor volumes and weights, generated high levels of HPV16 E6-specific T cells, and increased multifunctional CD8+ and CD4+ T cells in the tumor microenvironment. These studies provide the first evaluation to our knowledge of a therapeutic gorilla adenovirus HPV vaccine, PRGN-2009, showing promising preclinical antitumor efficacy and induction of HPV-specific T cells, along with the rationale for its evaluation in clinical trials.

Next generation polyphosphazene immunoadjuvant: Synthesis, self-assembly and in vivo potency with human papillomavirus VLPs-based vaccine

Poly[di(carboxylatomethylphenoxy)phosphazene] (PCMP), a new member of polyphosphazene immunoadjuvant family, is synthesized. In vitro assessment of a new macromolecule revealed hydrolytic degradation profile and immunostimulatory activity comparable to its clinical stage homologue PCPP; however, PCMP was characterized by a beneficial reduced sensitivity to the ionic environment. In vivo evaluation of PCMP potency was conducted with human papillomavirus (HPV) virus-like particles (VLPs) based RG1-VLPs vaccine. In contrast with previously reported self-assembly of polyphosphazene adjuvants with proteins, which typically results in the formation of complexes with multimeric display of antigens, PCMP surface modified VLPs in a composition dependent pattern, which at a high polymer-to VLPs ratio led to stabilization of antigenic particles. Immunization experiments in mice demonstrated that PCMP adjuvanted RG1-VLPs vaccine induced potent humoral immune responses, in particular, on the level of highly desirable protective cross-neutralizing antibodies, and outperformed PCPP and Alhydrogel adjuvanted formulations.

The epidemiologic and economic impact of a quadrivalent human papillomavirus vaccine in Thailand

BACKGROUND

The human papillomavirus (HPV) vaccine was introduced into Thailand's national immunization program in 2017 for 11-12 year old school girls. The objectives of this study were to examine the epidemiological consequences and cost-effectiveness of a routine quadrivalent HPV (4vHPV) vaccination and the routine 4vHPV vaccination plus 5-year catch-up vaccination by comparing with cervical cancer screening only (no vaccination) in Thailand.

METHOD

A transmission dynamic model was used to assess the cost-effectiveness of the routine 4vHPV vaccination and the routine 4vHPV vaccination plus catch-up vaccination, compared with no vaccination (screening only) in Thai population. The vaccination coverage rate assumptions were 95% in 11-12-year-old girls for the routine vaccination and 70% in 13-24 year-old females for the 5-year catch-up vaccination. Vaccination costs, direct medical costs of HPV-related diseases, and the number of quality of life years (QALYs) gained were calculated for over a 100-year time horizon with discount rate of 3%.

RESULT

The model indicated that the routine 4vHPV vaccination and the routine plus catch-up 4vHPV vaccination strategies could prevent approximately 434,130 and 472,502 cumulative cases of cervical cancer, 182,234 and 199,068 cumulative deaths from cervical cancer and 12,708,349 and 13,641,398 cumulative cases of HPV 6/11 related genital warts, respectively, when compared with no vaccination over 100 years. The estimated cost per QALY gained (ICER) when compared to no vaccination in Thailand was 8,370 THB/QALY for the routine vaccination and 9,650 THB/QALY for the routine with catch-up vaccination strategy.

CONCLUSION

Considering the recommended threshold of 160,000 THB/QALY for Thailand, the implementation of the routine 4vHPV vaccination either alone or plus the catch-up vaccination was cost-effective as compared to the cervical cancer screening only.

Anti-pulmonary metastases from cervical cancer responses induced by a human papillomavirus peptide vaccine adjuvanted with CpG-oligodeoxynucleotides in vivo

Metastasis, particularly hematogenous metastasis, is associated with poor prognosis in patients with cervical cancer. The lungs are the most common site for hematogenous metastasis of cervical cancer. The currently available therapeutic modalities, including surgery, radiotherapy, or chemotherapy do not provide satisfactory clinical outcome for patients with pulmonary metastases. Therefore, it is necessary to investigate an alternative efficacious treatment modality. Therapeutic vaccines may evoke tumor-specific immune responses in patients to attack tumor cells, representing an attractive treatment option for controlling metastatic tumors. Our previous study demonstrated that a single administration of a human papillomavirus 16 E7 peptide vaccine, adjuvanted with unmethylated CpG-oligodeoxynucleotides, induced the clearance of subcutaneous xenograft cervical cancer. In this study, we investigated the anti-metastases responses induced by this vaccine using a murine model of pulmonary metastases from cervical cancer. The results showed that subcutaneous administration of the vaccine inhibited the growth of pulmonary metastases, which may be attributed to the increased infiltration of CD4 + and CD8 + T cells, and decreased number of immunosuppressive cells (including myeloid-derived suppressive cells and tumor-associated macrophages) in the lungs. Meanwhile, the alteration in a panel of cytokines, chemokines, and matrix metalloproteinases induced by the vaccination may contribute to the re-modulation of the local suppressive environment and inhibition of pulmonary metastases. To the best of our knowledge, this is the first report on the efficacy of the vaccine formula against murine pulmonary metastases from cervical cancer.

Combined prophylactic and therapeutic immune responses against human papillomaviruses induced by a thioredoxin-based L2-E7 nanoparticle vaccine

Global burden of cervical cancer, the most common cause of mortality caused by human papillomavirus (HPV), is expected to increase during the next decade, mainly because current alternatives for HPV vaccination and cervical cancer screening programs are costly to be established in low-and-middle income countries. Recently, we described the development of the broadly protective, thermostable vaccine antigen Trx-8mer-OVX313 based on the insertion of eight different minor capsid protein L2 neutralization epitopes into a thioredoxin scaffold from the hyperthermophilic archaeon Pyrococcus furiosus and conversion of the resulting antigen into a nanoparticle format (median radius ~9 nm) upon fusion with the heptamerizing OVX313 module. Here we evaluated whether the engineered thioredoxin scaffold, in addition to humoral immune responses, can induce CD8⁺ T-cell responses upon incorporation of MHC-I-restricted epitopes. By systematically examining the contribution of individual antigen modules, we demonstrated that B-cell and T-cell epitopes can be combined into a single antigen construct without compromising either immunogenicity. While CD8⁺ T-cell epitopes had no influence on B-cell responses, the L2 polytope (8mer) and OVX313-mediated heptamerization of the final antigen significantly increased CD8⁺ T-cell responses. In a proof-of-concept experiment, we found that vaccinated mice remained tumor-free even after two consecutive tumor challenges, while unvaccinated mice developed tumors. A cost-effective, broadly protective vaccine with both prophylactic and therapeutic properties represents a promising option to overcome the challenges associated with prevention and treatment of HPV-caused diseases.

Currently, there are three licensed prophylactic vaccines available against HPV, but none of them shows a therapeutic effect on pre-existing infections. Thus, a prophylactic vaccine also endowed with a therapeutic activity presents application potentials to individuals regardless of their HPV-infection status. Such a dual-purpose vaccine would be particularly valuable for post-exposure prophylaxis and shields population from recurrent HPV infections. Here, we constructed a combined vaccine relying on L2- and E7-specific epitopes grafted onto the surface of a hyper-stable thioredoxin scaffold. The resulting antigen was converted into a nanoparticle format with the use of a heptamerization domain. Our data document that the modular design of the antigen allows combination of B-cell and T-cell epitopes in one antigen without compromising either’s immunogenicity. The antigen retains its ability to provide broad protection against different HPV types but also presents strong therapeutic effects in a mouse tumor model. Therefore, the vaccine is potentially capable of resolving productive infection as well as HPV-related malignancies, and thus benefitting both uninfected and already infected individuals. Moreover, our vaccine utilizes E. coli as protein producer and distribution does not require cold-chain, which reduces costs making it applicable to less-affluent countries.

FLT3L and granulocyte macrophage colony-stimulating factor enhance the anti-tumor and immune effects of an HPV16 E6/E7 vaccine

HPV16 infections promote the development and progression of cervical cancer. We investigated Fms-like Tyrosine Kinase 3 Ligand and granulocyte macrophage colony-stimulating factor as new adjuvants to an HPV16 vaccine. C57BL/6 mice were immunized by intramuscular injections of HPV16 E6/E7 plasmids every two weeks, three times in all. An in vivo imaging system was used to observe tumor growth and metastasis. Pathological changes to the heart, liver, spleen, lungs, brain and kidneys were recorded, and the survival rate of the mice was determined. The constructed HPV16 E6/E7 vaccine had no notable side effects in terms of physiological or biochemical indexes. Fms-like Tyrosine Kinase 3 Ligand and granulocyte macrophage colony-stimulating factor increased the inhibitory effects of the HPV16 E6/E7 vaccine on tumor growth and metastasis in vivo. The HPV16 E6/E7 vaccine enhanced the survival of mice and increased their serum-specific antibody and interferon-γ levels. Fms-like Tyrosine Kinase 3 Ligand and granulocyte macrophage colony-stimulating factor augmented these effects. In a cytotoxic lymphocyte killing test, Fms-like Tyrosine Kinase 3 Ligand and granulocyte macrophage colony-stimulating factor improved the ability of splenic lymphocytes from HPV16 E6/E7-vaccinated mice to kill B16 cells. As Fms-like Tyrosine Kinase 3 Ligand and granulocyte macrophage colony-stimulating factor enhanced the anti-tumor and immune effects of the HPV16 vaccine, these adjuvants should be considered for the treatment of cervical cancer.

Vaccination of Young Women Decreases Human Papillomavirus Transmission in Heterosexual Couples: Findings from the HITCH Cohort Study

BACKGROUND

Vaccination against human papillomaviruses (HPV) prevents HPV infections and, consequently, cervical lesions. However, the effect of vaccination on HPV transmission within couples is unknown.

METHODS

We used data from HITCH, a prospective cohort study of heterosexual couples (women ages 18-24 years) in Montreal, 2005 to 2013. Vaccination history was self-reported. Genital samples were tested for HPV DNA by PCR (linear array). Type-specific viral loads were quantified using real-time PCR. OR and HR were estimated using multilevel mixed-effects logistic regression and a parametric model for interval- censored survival-time data, respectively. Differences in viral loads were evaluated using the Friedman ANOVA test.

RESULTS

Among 497 couples, 12, 16, and 35 women received 1, 2, or 3 vaccination doses at baseline, respectively. Median age at vaccination was 18 years. Most women (92.1%) had their first coitus before vaccination. At baseline, partner concordance of persistent HPV6/11/16/18 infections was lower in vaccinated than unvaccinated women [adjusted OR = 0.10; 95% confidence interval (CI), 0.01-0.65] but not for non α7/α9/α10-HPV types (adjusted OR = 1.00; 95% CI, 0.44-2.29). Incidence of persistent α7/α9/α10 HPV types in women was inversely associated with vaccination status at baseline (adjusted HR = 0.12; 95% CI, 0.03-0.47). Likewise, male partners of vaccinated women had a lower incidence of α7/α9/α10 HPV infections (adjusted OR = 0.22; 95% CI, 0.05-0.95). Vaccinated women with HPV 6/11/16/18 infections had lower viral loads (P = 0.001) relative to unvaccinated women.

CONCLUSIONS

Vaccination of sexually active women significantly reduced transmission of α7/α9/α10 HPV types in heterosexual couples.

IMPACT

These results underscore and quantify the positive effect of HPV vaccination on HPV transmission within heterosexual couples.

Population-level impact and herd effects following the introduction of human papillomavirus vaccination programmes: updated systematic review and meta-analysis

BACKGROUND

More than 10 years have elapsed since human papillomavirus (HPV) vaccination was implemented. We did a systematic review and meta-analysis of the population-level impact of vaccinating girls and women against human papillomavirus on HPV infections, anogenital wart diagnoses, and cervical intraepithelial neoplasia grade 2+ (CIN2+) to summarise the most recent evidence about the effectiveness of HPV vaccines in real-world settings and to quantify the impact of multiple age-cohort vaccination.

METHODS

In this updated systematic review and meta-analysis, we used the same search strategy as in our previous paper. We searched MEDLINE and Embase for studies published between Feb 1, 2014, and Oct 11, 2018. Studies were eligible if they compared the frequency (prevalence or incidence) of at least one HPV-related endpoint (genital HPV infections, anogenital wart diagnoses, or histologically confirmed CIN2+) between pre-vaccination and post-vaccination periods among the general population and if they used the same population sources and recruitment methods before and after vaccination. Our primary assessment was the relative risk (RR) comparing the frequency (prevalence or incidence) of HPV-related endpoints between the pre-vaccination and post-vaccination periods. We stratified all analyses by sex, age, and years since introduction of HPV vaccination. We used random-effects models to estimate pooled relative risks.

FINDINGS

We identified 1702 potentially eligible articles for this systematic review and meta-analysis, and included 65 articles in 14 high-income countries: 23 for HPV infection, 29 for anogenital warts, and 13 for CIN2+. After 5-8 years of vaccination, the prevalence of HPV 16 and 18 decreased significantly by 83% (RR 0·17, 95% CI 0·11-0·25) among girls aged 13-19 years, and decreased significantly by 66% (RR 0·34, 95% CI 0·23-0·49) among women aged 20-24 years. The prevalence of HPV 31, 33, and 45 decreased significantly by 54% (RR 0·46, 95% CI 0·33-0·66) among girls aged 13-19 years. Anogenital wart diagnoses decreased significantly by 67% (RR 0·33, 95% CI 0·24-0·46) among girls aged 15-19 years, decreased significantly by 54% (RR 0·46, 95% CI 0.36-0.60) among women aged 20-24 years, and decreased significantly by 31% (RR 0·69, 95% CI 0·53-0·89) among women aged 25-29 years. Among boys aged 15-19 years anogenital wart diagnoses decreased significantly by 48% (RR 0·52, 95% CI 0·37-0·75) and among men aged 20-24 years they decreased significantly by 32% (RR 0·68, 95% CI 0·47-0·98). After 5-9 years of vaccination, CIN2+ decreased significantly by 51% (RR 0·49, 95% CI 0·42-0·58) among screened girls aged 15-19 years and decreased significantly by 31% (RR 0·69, 95% CI 0·57-0·84) among women aged 20-24 years.

INTERPRETATION

This updated systematic review and meta-analysis includes data from 60 million individuals and up to 8 years of post-vaccination follow-up. Our results show compelling evidence of the substantial impact of HPV vaccination programmes on HPV infections and CIN2+ among girls and women, and on anogenital warts diagnoses among girls, women, boys, and men. Additionally, programmes with multi-cohort vaccination and high vaccination coverage had a greater direct impact and herd effects.

FUNDING

WHO, Canadian Institutes of Health Research, Fonds de recherche du Québec - Santé.

Potential effectiveness of prophylactic HPV immunization for men who have sex with men in the Netherlands: A multi-model approach

BACKGROUND

Men who have sex with men (MSM) are at high risk for anal cancer, primarily related to human papillomavirus genotype 16 (HPV16) infections. At 8.5 per 100,000 per year, the incidence rate of anal cancer among MSM is similar to that of cervical cancer among adult women in the Netherlands. However, MSM are not included in most HPV vaccination programs. We explored the potential effectiveness of prophylactic immunization in reducing anogenital HPV16 transmission among MSM in the Netherlands.

METHODS AND FINDINGS

We developed a range of mathematical models for penile-anal HPV16 transmission, varying in sexual contact structure and natural history of infection, to provide robust and plausible predictions about the effectiveness of targeted vaccination. Models were informed by an observational cohort study among MSM in Amsterdam, 2010-2013. Parameters on sexual behavior and HPV16 infections were obtained by fitting the models to data from 461 HIV-negative study participants, considered representative of the local MSM population. We assumed 85% efficacy of vaccination against future HPV16 infections as reported for HIV-negative MSM, and age-specific uptake rates similar to those for hepatitis B vaccination among MSM in the Netherlands. Targeted vaccination was contrasted with vaccination of 12-year-old boys at 40% uptake in base-case scenarios, and we also considered the effectiveness of a combined strategy. Offering vaccine to MSM without age restrictions resulted in a model-averaged 27.3% reduction (90% prediction interval [PI] 11.9%-37.5%) in prevalence of anal HPV16 infections, assuming similar uptake among MSM as achieved for hepatitis B vaccination. The predicted reduction improved to 46.1% (90% PI 21.8%-62.4%) if uptake rates among MSM were doubled. The reductions in HPV16 infection prevalence were mostly achieved within 30 years of a targeted immunization campaign, during which they exceeded those induced by vaccinating 40% of preadolescent boys, if started simultaneously. The reduction in anal HPV16 prevalence amounted to 74.8% (90% PI 59.8%-93.0%) under a combined vaccination strategy. HPV16 prevalence reductions mostly exceeded vaccine coverage projections among MSM, illustrating the efficiency of prophylactic immunization even when the HPV vaccine is given after sexual debut. Mode of protection was identified as the key limitation to potential effectiveness of targeted vaccination, as the projected reductions were strongly reduced if we assumed no protection against future infections in recipients with prevalent infection or infection-derived immunity at the time of immunization. Unverified limitations of our study include the sparsity of data to inform the models, the omission of oral sex in transmission to the penile or anal site, and the restriction that our modeling results apply primarily to HIV-negative MSM.

CONCLUSIONS

Our findings suggest that targeted vaccination may generate considerable reductions in anogenital HPV16 infections among MSM, and has the potential to accelerate anal cancer prevention, especially when combined with sex-neutral vaccination in preadolescence.

Toward a Model of HPV Vaccine Series Completion in Adolescent Hispanic Males: Identifying Mothers' Salient Behavioral, Normative, and Control Beliefs

Human papillomavirus (HPV) vaccine series completion among adolescent Hispanic males (35%) is lower than the Healthy People 2020 80% goal. This directed qualitative content analysis identified mothers' beliefs about their sons completing the series. We found that mothers (N = 19) (1) express positive feelings; (2) believe the vaccine has positive effects; (3) identify the father and doctors as supporters and friends as nonsupporters; (4) list health insurance, transportation, and clinic reminders as facilitators; and (5) mention affordability as a barrier to vaccine completion. Results provide guidance for interventions. Increasing HPV vaccination among boys will decrease the overall incidence of HPV in this population.

A Novel Human Papillomavirus 16 L1 Pentamer-Loaded Hybrid Particles Vaccine System: Influence of Size on Immune Responses

Cervical cancer remains the second-most prevalent female malignancy around the world, leading to a great majority of cancer-related mortality that occurs mainly in developing countries. Developing an effective and low-cost vaccine against human papillomavirus (HPV) infection, especially in medically underfunded areas, is urgent. Compared with vaccines based on HPV L1 viruslike particles (VLPs) in the market, recombinant HPV L1 pentamer expressed in Escherichia coli represents a promising and potentially cost-effective vaccine for preventing HPV infection. Hybrid particles comprising a polymer core and lipid shell have shown great potential compared to conventional aluminum salts adjuvant and is urgently needed for HPV L1 pentamer vaccines. It is well-reported that particle sizes are crucial in regulating immune responses. Nevertheless, reports on the relationship between the particulate size and the resultant immune response have been in conflict, and there is no answer to how the size of particles regulates specific immune response for HPV L1 pentamer-based candidate vaccines. Here, we fabricated HPV 16 L1 pentamer-loaded poly(d,l-lactide- co-glycolide) (PLGA)/lecithin hybrid particles with uniform sizes (0.3, 1, and 3 μm) and investigated the particle size effects on antigen release, activation of lymphocytes, dendritic cells (DCs) activation and maturation, follicular helper CD4⁺ T (TFH) cells differentiation, and release of pro-inflammatory cytokines and chemokines. Compared with the other particle sizes, 1 μm particles induced more powerful antibody protection and yielded more persistent antibody responses, as well as more heightened anamnestic responses upon repeat vaccination. The superior immune responses might be attributed to sustainable antigen release and robust antigen uptake and transport and then further promoted a series of cascade reactions, including enhanced DCs maturation, increased lymphocytes activation, and augmented TFH cells differentiation in draining lymph nodes (DLNs). Here, a powerful and economical platform for HPV vaccine and a comprehensive understanding of particle size effect on immune responses for HPV L1 pentamer-based candidate vaccines are provided.

The Combined Use of Melatonin and an Indoleamine 2,3-Dioxygenase-1 Inhibitor Enhances Vaccine-Induced Protective Cellular Immunity to HPV16-Associated Tumors

Immunotherapy has become an important ally in the fight against distinct types of cancer. However, the metabolic plasticity of the tumor environment frequently influences the efficacy of therapeutic procedures, including those based on immunological tools. In this scenario, immunometabolic adjuvants arise as an alternative toward the development of more efficient cancer therapies. Here we demonstrated that the combination of melatonin, a neuroimmunomodulator molecule, and an indoleamine 2,3-dioxygenase (IDO) inhibitor (1-methyl-DL-tryptophan, DL-1MT) improves the efficacy of an immunotherapy (gDE7) targeting human papillomavirus (HPV)-associated tumors. Melatonin or IDO inhibitors (D-1MT and DL-1MT) directly reduced proliferation, migration, adhesion and viability of a tumor cell line (TC-1), capable to express the HPV-16 E6 and E7 oncoproteins, but could not confer in vivo antitumor protection effects. Nonetheless, combination of gDE7 with melatonin or D-1MT or DL-1MT enhanced the antitumor protective immunity of gDE7-based vaccine in mice. Notably, expression of IDO1 in stromal cells and/or immune cells, but not in tumor cells, inhibited the antitumor effects of the gDE7, as demonstrated in IDO1-deficient mice. Finally, co-administration of gDE7, melatonin and DL-1MT further improved the protective antitumor effects and the numbers of circulating E7-specific CD8+ T cells in mice previously transplanted with TC-1 cells. The unprecedented combination of melatonin and IDO inhibitors, as immunometabolic adjuvants, thus, represents a new and promising alternative for improving the efficacy of immunotherapeutic treatments of HPV-associated tumors.

Parents' Views on the Best and Worst Reasons for Guideline-Consistent HPV Vaccination

Background: Human papillomavirus (HPV) vaccination could prevent most HPV-associated cancers, but few U.S. adolescents are vaccinated according to guidelines. To inform efforts to counsel parents more effectively, we sought to quantify their views on the best and worst reasons for guideline-consistent HPV vaccination. We hypothesized that parents' views would differ according to their vaccination confidence.Methods: We developed a best-worst scaling experiment to evaluate 11 reasons healthcare providers commonly give for HPV vaccination. The instrument was administered in 2016 via a national online survey to 1,177 parents of adolescents. Parents completed 11 choice tasks of 5 reasons each, indicating the best and worst reason in each task. We used conditional logistic regression to rank reasons for the sample overall and by vaccination confidence (low/high).Results: Parents viewed cancer prevention as the best reason for HPV vaccination (P < 0.001). Other commonly endorsed reasons were preventing a common infection, having lasting benefits, or being a safe vaccine (all P < 0.001). Reasons viewed as worst were: It is a scientific breakthrough; I got it for my own child; and your child is due (all P < 0.001). Stratified analyses indicated small differences in how often parents with low versus high vaccination confidence endorsed messages (P < 0.001), but the two groups ranked reasons similarly overall.Conclusions: Parents prioritized cancer prevention as the best reason for guideline-consistent HPV vaccination. Several other common reasons, including having vaccinated one's own child, may warrant additional testing.Impact: Providers should emphasize cancer prevention when discussing HPV vaccination, as recommended by the Centers for Disease Control and Prevention, the President's Cancer Panel, and others. Cancer Epidemiol Biomarkers Prev; 27(7); 762-7. ©2018 AACR.

Design and statistical considerations for studies evaluating the efficacy of a single dose of the human papillomavirus (HPV) vaccine

Cervical cancer is a leading cause of cancer mortality in women worldwide. Human papillomavirus (HPV) types 16 and 18 cause about 70% of all cervical cancers. Clinical trials have demonstrated that three doses of either commercially available HPV vaccine, Cervarix ® or Gardasil ®, prevent most new HPV 16/18 infections and associated precancerous lesions. Based on evidence of immunological non-inferiority, 2-dose regimens have been licensed for adolescents in the United States, European Union, and elsewhere. However, if a single dose were effective, vaccine costs would be reduced substantially and the logistics of vaccination would be greatly simplified, enabling vaccination programs in developing countries. The National Cancer Institute (NCI) and the Agencia Costarricense de Investigaciones Biomédicas (ACIB) are conducting, with support from the Bill & Melinda Gates Foundation and the International Agency for Research on Cancer (IARC), a large 24,000 girl study to evaluate the efficacy of a 1-dose regimen. The first component of the study is a four-year non-inferiority trial comparing 1- to 2-dose regimens of the two licensed vaccines. The second component is an observational study that estimates the vaccine efficacy (VE) of each regimen by comparing the HPV infection rates in the trial arms to those in a contemporaneous survey group of unvaccinated girls. In this paper, we describe the design and statistical analysis for this study. We explain the advantage of defining non-inferiority on the absolute risk scale when the expected event rate is near 0 and, given this definition, suggest an approach to account for missing clinic visits. We then describe the problem of estimating VE in the absence of a randomized placebo arm and offer our solution.

Opportunities and challenges for human papillomavirus vaccination in cancer

The discovery of genotype 16 as the prototype oncogenic human papillomavirus (HPV) initiated a quarter century of laboratory and epidemiological studies that demonstrated their necessary, but not sufficient, aetiological role in cervical and several other anogenital and oropharyngeal cancers. Early virus-induced immune deviation can lead to persistent subclinical infection that brings the risk of progression to cancer. Effective secondary prevention of cervical cancer through cytological and/or HPV screening depends on regular and widespread use in the general population, but coverage is inadequate in low-resource settings. The discovery that the major capsid antigen L1 could self-assemble into empty virus-like particles (VLPs) that are both highly immunogenic and protective led to the licensure of several prophylactic VLP-based HPV vaccines for the prevention of cervical cancer. The implementation of vaccination programmes in adolescent females is underway in many countries, but their impact critically depends on the population coverage and is improved by herd immunity. This Review considers how our expanding knowledge of the virology and immunology of HPV infection can be exploited to improve vaccine technologies and delivery of such preventive strategies to maximize reductions in HPV-associated disease, including incorporation of an HPV vaccine covering oncogenic types within a standard multitarget paediatric vaccine.

Awareness of and Attitudes toward Human Papillomavirus Vaccination among Adults in Korea: 9-Year Changes in Nationwide Surveys

PURPOSE

Human papillomavirus (HPV) vaccination has been included in the National Immunization Program in Korea since 2016. We aimed to evaluate changes in the awareness of and attitudes toward HPV vaccination, among adults in Korea since the first introduction of the vaccines in 2007.

MATERIALS AND METHODS

A nationwide population-based survey was conducted in 2016 for 1,200 nationally representative Korean men and women; the data obtained were compared with the data from the nationwide survey conducted in 2007.

RESULTS

A significant increase in the awareness of HPV infection (35.8%) and vaccination (36.9%) was observed in 2016 from 13.3% and 8.6% in 2007, respectively. Willingness to be vaccinated against HPV decreased from 55.0% in 2007 to 25.8% in 2016, and the proportion of respondents expressing uncertainty increased from 28.3% in 2007 to 43.3% in 2016. Only 12.1% of men and 22.0% of women knew about the free national HPV vaccination program for girls, launched in June 2016. Younger women, with higher income level, awareness of the HPV vaccine, and perception of the seriousness of infections had a higher willingness to be vaccinated. A high education level, awareness of HPV infection and vaccination, and perception of the seriousness of infection were positively associated with the willingness of respondents to vaccinate their daughters.

CONCLUSION

Raising the awareness of HPV infection and vaccination with appropriate knowledge is necessary for the successful implementation of the national HPV vaccination program.

Uptake of the human papillomavirus vaccine in Kenya: testing the health belief model through pathway modeling on cohort data

BACKGROUND

Many studies investigate HPV vaccine acceptability, applying health behavior theories to identify determinants; few include real uptake, the final variable of interest. This study investigated the utility of the Health Belief Model (HBM) in predicting HPV vaccine uptake in Kenya, focusing on the importance of promotion, probing willingness to vaccinate as precursor of uptake and exploring the added value of personal characteristics.

METHODS

Longitudinal data were collected before and after a pilot HPV vaccination program in Eldoret among mothers of eligible girls (N = 255). Through pathway modeling, associations between vaccine uptake and the HBM constructs, willingness to vaccinate and adequate promotion were examined. Adequate promotion was defined as a personal evaluation of promotional information received. Finally, baseline cervical cancer awareness and socio-demographic variables were added to the model verifying their direct, mediating or moderating effects on the predictive value of the HBM.

RESULTS

Perceiving yourself as adequately informed at follow-up was the strongest determinant of vaccine uptake. HBM constructs (susceptibility, self-efficacy and foreseeing father's refusal as barrier) only influenced willingness to vaccinate, which was not correlated with vaccination. Baseline awareness of cervical cancer predicted uptake.

CONCLUSIONS

The association between adequate promotion and vaccination reveals the importance of triggers beyond personal control. Adoption of new health behaviors might be more determined by organizational variables, such as promotion, than by prior personal beliefs. Assessing users' and non-users' perspectives during and after implementing a vaccination program can help identifying stronger determinants of vaccination behavior.

Factors related to HPV vaccine uptake and 3-dose completion among women in a low vaccination region of the USA: an observational study

BACKGROUND

To assess the demographic and attitudinal factors associated with HPV vaccine initiation and completion among 18-26 year old women in Utah.

METHOD

Between January 2013 and December 2013, we surveyed 325 women from the University of Utah Community Clinics about their HPV vaccine related beliefs and behaviors. Odds ratios (ORs) were estimated from logistic regression models to identify variables related to HPV vaccine initiation and series completion.

RESULTS

Of the 325 participants, 204 (62.8 %) had initiated the vaccine and 159 (48.9 %) had completed the 3-dose series. The variables associated with HPV vaccine initiation were lower age (OR = 1.18 per year); being unmarried (OR = 3.62); not practicing organized religion (OR = 2.40); knowing how HPV spreads (OR = 6.29); knowing the connection between HPV and cervical cancer (OR = 3.90); a belief in the importance of preventive vaccination (OR = 2.45 per scale unit); strength of doctor recommendation (OR = 1.86 per scale unit); and whether a doctor's recommendation was influential (OR = 1.70 per scale unit). These variables were also significantly associated with HPV vaccine completion.

CONCLUSION

The implications of these findings may help inform policies and interventions focused on increasing HPV vaccination rates among young women. For example, without this information, programs might focus on HPV awareness; however, the results of this study illustrate that awareness is already high (near saturation) in target populations and other factors, such as strong and consistent physician recommendations, are more pivotal in increasing likelihood of vaccination. Additionally, our findings indicate the need for discussions of risk assessment be tailored to the young adult population.

Cervical cancer prevention and treatment research in Africa: a systematic review from a public health perspective

BACKGROUND

Women living in Africa experience the highest burden of cervical cancer. Research and investment to improve vaccination, screening, and treatment efforts are critically needed. We systematically reviewed and characterized recent research within a broader public health framework to organize and assess the range of cervical cancer research in Africa.

METHODS

We searched online databases and the Internet for published articles and cervical cancer reports in African countries. Inclusion criteria included publication between 2004 and 2014, cervical cancer-related content pertinent to one of the four public health categories (primary, secondary, tertiary prevention or quality of life), and conducted in or specifically relevant to countries or regions within the African continent. The study design, geographic region/country, focus of research, and key findings were documented for each eligible article and summarized to illustrate the weight and research coverage in each area. Publications with more than one focus (e.g. secondary and tertiary prevention) were categorized by the primary emphasis of the paper. Research specific to HIV-infected women or focused on feasibility issues was delineated within each of the four public health categories.

RESULTS

A total of 380 research articles/reports were included. The majority (54.6 %) of cervical cancer research in Africa focused on secondary prevention (i.e., screening). The number of publication focusing on primary prevention (23.4 %), particularly HPV vaccination, increased significantly in the past decade. Research regarding the treatment of precancerous lesions and invasive cervical cancer is emerging (17.6 %), but infrastructure and feasibility challenges in many countries have impeded efforts to provide and evaluate treatment. Studies assessing aspects of quality of life among women living with cervical cancer are severely limited (4.1 %). Across all categories, 11.3 % of publications focused on cervical cancer among HIV-infected women, while 17.1 % focused on aspects of feasibility for cervical cancer control efforts.

CONCLUSIONS

Cervical cancer research in African countries has increased steadily over the past decade, but more is needed. Tertiary prevention (i.e. treatment of disease with effective medicine) and quality of life of cervical cancer survivors are two severely under-researched areas. Similarly, there are several countries in Africa with little to no research ever conducted on cervical cancer.

Multisite HPV16/18 Vaccine Efficacy Against Cervical, Anal, and Oral HPV Infection

BACKGROUND

Previous Costa Rica Vaccine Trial (CVT) reports separately demonstrated vaccine efficacy against HPV16 and HPV18 (HPV16/18) infections at the cervical, anal, and oral regions; however, the combined overall multisite efficacy (protection at all three sites) and vaccine efficacy among women infected with HPV16 or HPV18 prior to vaccination are less known.

METHODS

Women age 18 to 25 years from the CVT were randomly assigned to the HPV16/18 vaccine (Cervarix) or a hepatitis A vaccine. Cervical, oral, and anal specimens were collected at the four-year follow-up visit from 4186 women. Multisite and single-site vaccine efficacies (VEs) and 95% confidence intervals (CIs) were computed for one-time detection of point prevalent HPV16/18 in the cervical, anal, and oral regions four years after vaccination. All statistical tests were two-sided.

RESULTS

The multisite woman-level vaccine efficacy was highest among "naïve" women (HPV16/18 seronegative and cervical HPV high-risk DNA negative at vaccination) (vaccine efficacy = 83.5%, 95% CI = 72.1% to 90.8%). Multisite woman-level vaccine efficacy was also demonstrated among women with evidence of a pre-enrollment HPV16 or HPV18 infection (seropositive for HPV16 and/or HPV18 but cervical HPV16/18 DNA negative at vaccination) (vaccine efficacy = 57.8%, 95% CI = 34.4% to 73.4%), but not in those with cervical HPV16 and/or HPV18 DNA at vaccination (anal/oral HPV16/18 VE = 25.3%, 95% CI = -40.4% to 61.1%). Concordant HPV16/18 infections at two or three sites were also less common in HPV16/18-infected women in the HPV vaccine vs control arm (7.4% vs 30.4%, P < .001).

CONCLUSIONS

This study found high multisite vaccine efficacy among "naïve" women and also suggests the vaccine may provide protection against HPV16/18 infections at one or more anatomic sites among some women infected with these types prior to HPV16/18 vaccination.

HPV9 Vaccine for the Prevention of Human Papillomavirus-Related Cancers

Human papillomavirus (HPV) is the most common sexually transmitted infection (STI) in the United States, with approximately 79 million Americans currently infected. Persistent infection with HPV has been identified as the causative factor in the development of invasive cervical cancer as well as other oral and genital cancers in women and men. The quadravalent HPV4 vaccine has been available since 2006. In December 2014, the U.S. Food and Drug Administration (FDA) approved the HPV9 vaccine that provides coverage for five additional oncogenic strains of HPV that are not included in the first generation vaccine.

HPV Vaccine Confers Multisite Protection

Findings from a large multisite study show that the human papillomavirus vaccine can be effective in protecting women ages 18 to 25 against cervical, anal, and oral infections, even among those previously exposed to the virus.

Facebook for Health Promotion: Female College Students' Perspectives on Sharing HPV Vaccine Information Through Facebook

Facebook, a social network site, has been widely used among young adults. However, its potential to be used as a health promotion medium has not been fully examined. This study explored Facebook's potential for sharing human papillomavirus (HPV) vaccine information among female college students in Hawai'i. Culturally tailored flyers and handouts were developed and distributed at one large university in Hawai'i to recruit female college students between the age of 18 and 26 having an active Facebook account. Three focus group meetings were conducted to gather student perspectives about how information about HPV vaccine may be best shared via Facebook. We found that students believed Facebook is a good awareness tool but they needed more knowledge about the HPV vaccine to feel comfortable sharing the information. Participants preferred forwarding information to chatting about HPV. Some participants expressed concern that their Facebook friends would think the HPV vaccine information they forwarded on Facebook is spam. Participants suggested prefacing the posted HPV vaccine information with a personal note in their own words to make the message more interesting and relevant to their Facebook friends. Future interventions using Facebook to promote HPV vaccine could provide students with HPV vaccine information from credible sources and ask students to attach personal testimonials or endorsements while forwarding the information on Facebook.

Sequential cisplatin therapy and vaccination with HPV16 E6E7L2 fusion protein in saponin adjuvant GPI-0100 for the treatment of a model HPV16+ cancer

Clinical studies suggest that responses to HPV16 E6E7L2 fusion protein (TA-CIN) vaccination alone are modest, and GPI-0100 is a well-tolerated, potent adjuvant. Here we sought to optimize both the immunogenicity of TA-CIN via formulation with GPI-0100 and treatment of HPV16+ cancer by vaccination after cisplatin chemotherapy. HPV16 neutralizing serum antibody titers, CD4+ T cell proliferative and E6/E7-specific CD8+ T cell responses were significantly enhanced when mice were vaccinated subcutaneously (s.c.) or intramuscularly (i.m.) with TA-CIN formulated with GPI-0100. Vaccination was tested for therapy of mice bearing syngeneic HPV16 E6/E7+ tumors (TC-1) either in the lung or subcutaneously. Mice treated with TA-CIN/GPI-0100 vaccination exhibited robust E7-specific CD8+ T cell responses, which were associated with reduced tumor burden in the lung, whereas mice receiving either component alone were similar to controls. Since vaccination alone was not sufficient for cure, mice bearing s.c. TC-1 tumor were first treated with two doses of cisplatin and then vaccinated. Vaccination with TA-CIN/GPI-0100 i.m. substantially retarded tumor growth and extended survival after cisplatin therapy. Injection of TA-CIN alone, but not GPI-0100, into the tumor (i.t.) was similarly efficacious after cisplatin therapy, but the mice eventually succumbed. However, tumor regression and extended remission was observed in 80% of the mice treated with cisplatin and then intra-tumoral TA-CIN/GPI-0100 vaccination. These mice also exhibited robust E7-specific CD8+ T cell and HPV16 neutralizing antibody responses. Thus formulation of TA-CIN with GPI-0100 and intra-tumoral delivery after cisplatin treatment elicits potent therapeutic responses in a murine model of HPV16+ cancer.

Genomic diversity of human papillomaviruses (HPV) and clinical implications: an overview in adulthood and childhood

During the last years, several researchers have highlighted the importance of characterizing more than one genomic region in order to detect recombination and classify variants of human papillomaviruses (HPVs) properly. HPVs variants differ in their biological, molecular and chemical properties. Therefore, this genomic diversity can present differences in the natural history and pathogenicity of HPVs. Different 'high-risk' HPVs variants of the genotypes HPV 16 and 18 can confer varied risks of viral persistence in the human cervix and influence HPVs progression to cervical cancer. Moreover, different 'low-risk' HPVs variants of the genotypes HPV 6 and 11 can play a unique role in the development of anogenital and cutaneous warts, recurrent respiratory papillomatosis (RRP) and ophthalmic pterygium. In future, the precise impact of genomic HPVs diversity to the clinical course of HPVs-associated diseases as well as to the efficacy of the current HPVs vaccines remains to be elucidated.

Advancing cervical cancer prevention in India: implementation science priorities

Cervical cancer is the leading cause of cancer mortality in India, accounting for 17% of all cancer deaths among women aged 30 to 69 years. At current incidence rates, the annual burden of new cases in India is projected to increase to 225,000 by 2025, but there are few large-scale, organized cervical cancer prevention programs in the country. We conducted a review of the cervical cancer prevention research literature and programmatic experiences in India to summarize the current state of knowledge and practices and recommend research priorities to address the gap in services. We found that research and programs in India have demonstrated the feasibility and acceptability of cervical cancer prevention efforts and that screening strategies requiring minimal additional human resources and laboratory infrastructure can reduce morbidity and mortality. However, additional evidence generated through implementation science research is needed to ensure that cervical cancer prevention efforts have the desired impact and are cost-effective. Specifically, implementation science research is needed to understand individual- and community-level barriers to screening and diagnostic and treatment services; to improve health care worker performance; to strengthen links among screening, diagnosis, and treatment; and to determine optimal program design, outcomes, and costs. With a quarter of the global burden of cervical cancer in India, there is no better time than now to translate research findings to practice. Implementation science can help ensure that investments in cervical cancer prevention and control result in the greatest impact.

[Viral infection--a diverse causative agent of cancer]

Viral infections are a common cause for the development of cancer. Most common among the cancer-inducing viruses are human papillomaviruses, which cause cervical cancer among other things. Cancer viruses aim to keep their host cells alive and simultaneously use their oncogenes to interfere with cellular phenomena such as proliferation and programmed cell death. The most effective way of preventing viral cancers is to reduce the frequency of cancer virus infections by using vaccinations and by intervening in high-risk behavior. In addition, the infections must be detected and treated in advance of cancer development.

Predicting individual affect of health interventions to reduce HPV prevalence

Recently, human papilloma virus (HPV) has been implicated to cause several throat and oral cancers and HPV is established to cause most cervical cancers. A human papilloma virus vaccine has been proven successful to reduce infection incidence in FDA clinical trials, and it is currently available in the USA. Current intervention policy targets adolescent females for vaccination; however, the expansion of suggested guidelines may extend to other age groups and males as well. This research takes a first step toward automatically predicting personal beliefs, regarding health intervention, on the spread of disease. Using linguistic or statistical approaches, sentiment analysis determines a text's affective content. Self-reported HPV vaccination beliefs published in web and social media are analyzed for affect polarity and leveraged as knowledge inputs to epidemic models. With this in mind, we have developed a discrete-time model to facilitate predicting impact on the reduction of HPV prevalence due to arbitrary age- and gender-targeted vaccination schemes.

Multiple human papilloma virus types in cervical infections: competition or synergy?

Coinfection with multiple human papilloma virus (HPV) types is common in cervical HPV infection. To evaluate if infections with different HPV types occur independently, we examined 3558 women above 15 years of age suspected of cervical HPV infection. Among them, 1842 (52%) women were HPV negative and 1716 (48%) were HPV positive as analysed by a PCR-based commercial microarray assay for mucosal types. Of the HPV-positive samples, 824 (48%) had single infections, while 892 (52%) had multiple infections. Observed numbers of concurrent HPV types differed from expected numbers under the assumption of independence between infections by the various HPV types. Significant positive associations were observed for 16 pairs of HPV types in statistical analysis accounting for mass significance. Significant negative associations were also found, i.e. women with HPV-16 infection had 0.4 times the odds of having HPV-51 compared with women not infected with HPV-16. HPV-16 was the only type with odds ratios <1 for all pairwise combinations. While our findings of statistically significant coexistence do not prove biological dependence among HPV types, they do suggest that infections with some HPV types may depend on the existence of certain other HPV types. Any interaction between coexisting HPV types could either decrease or increase the efficacy of current HPV vaccines that offer mainly type-specific protection, depending on whether the types vaccinated against compete with other HPV types or not.

Anti-human papillomavirus therapeutics: facts & future

Even after 25 years of establishing Human Papillomavirus (HPV) as the causative agent for cervical cancer, effective treatment of HPV infection still unavailable. Comprehensive efforts especially for targeting HPV infection have been made only in recent years. Conventional physical ablation of HPV-induced lesions such as cryo-therapy, photo-therapy, LEEP, laser cone-biopsy and localized radiotherapy are shown to be effective to some extent in treating localized lesions where the removal of diseased tissue is associated with removal of transforming keratinocytes harboring HPV. Apart from currently available prophylactic vaccines which prevent the viral entry and should be given prior to viral exposure, several attempts are being made to develop therapeutic vaccines that could treat prevailing HPV infection. In addition, immunomodulators like interferons and imiquimod that have been shown to elicit cytokine milieu to enhance host immune response against HPV infection. Also, antiviral approaches such as RNA interference (RNAi) nucleotide analogs, antioxidants and herbal derivatives have shown effective therapeutic potential against HPV infection. These leads are being tested in pre-clinical and clinical studies. Present article provides a brief overview of conventional therapies for HPV-associated diseases. Potential of non-ablative anti-HPV treatment modalities that could prove useful for either elimination of HPV in early stages of infection when the virus is not integrated into the host cell genome or suppression of the expression of viral oncogenes that dys-regulate the host cell cycle following transformation is discussed.

Genotypes of the human papillomavirus: relevance to Indian field trials of the vaccine

Highly effective HPV vaccines are likely to become available for use in India shortly. The availability and validation of the vaccines to prevent oncogenic HPV infection associated lesions from progressing to cancer has clearly offered a cost effective long-term strategy to reduce the cervical cancer burden, particularly for developing countries where effective screening programmes are not available. The enthusiasm for these new vaccines duly justified, are we in reality targeting the actual delinquent by prompting these vaccines in India? The answer would be no as we may not be essentially implementing a rational fool-proof vaccine program which will aid in preventing HPV-related diseases, for the simple reason that there is a lack of understanding about the underlying HPV types responsible for cervical cancer in India. Field trials involving large populations form a major part of continued analysis in understanding any disease and India is still short of such a trial as far as cervical cancer is concerned. Conducting such studies, might also act as prevention programs that will save lives and improve public health in a substantive manner.

Human papillomavirus vaccines: current issues & future

Cervical cancer is the leading cause of cancer mortality among women in worldwide. Some 99 per cent of cervical cancer cases are linked to genital infection with human papillomaviruses (HPVs) comprised of approximately 15 oncogenic genital HPV types. Most HPV infections resolve spontaneously. But, the remainder persist and may then progress to cervical cancer in some women. In high-resource countries, the best way to prevent cervical cancer is to implement organised gynaecological screening programs with appropriate treatment of the detected pre-cancerous lesions. However, in developing countries, this method is not practicable because of cost and complexity of proper screening. Vaccines against HPV infections hold promise to reduce incidence of cervical cancer cost-effectively. Two Prophylactic HPV vaccines have been thus far developed: Gardasil(R), a quadrivalent vaccine targeting HPV-6, -11, -16 and -18) and Cervarix(R), a bivalent vaccine which targets HPV-16 and -18. Both vaccines contain L1 virus-like particles (VLPs) derived from HPV-16 and -18 which are most frequently associated with cervical cancer. The L1-VLP vaccines are HPV type-specific and therefore can effectively prevent infection of a HPV type in question alone. Therefore, the L1-VLP vaccines are hoped to be multivalent for 15 oncogenic HPV types, which comes at a price. Otherwise, costly cytologic screening for cervical cancer is still necessary. The current HPV vaccines thus may not be ultimate strategy and study on new HPV vaccines is needed. Broad-spectrum prophylactic vaccines against all oncogenic HPV types and therapeutic vaccines for clearance of HPV-related cervical lesion are being developed.

Immune responses to human papilloma viruses

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 response and the lesions regress. Regression of ano-genital warts is accompanied histologically by a CD4+ T cell dominated Th1 response; animal models support this and provide evidence that the response is modulated by CD4+ T cell dependent mechanisms. 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 central importance of the CD4+ T cell population in the control of HPV infection is shown by the increased prevalence of HPV infections and HGSIL in individuals immunosuppressed as a consequence of HIV infection. The prolonged duration of infection associated with HPV seems to be associated with effective evasion of innate immunity as reflected in the absence of inflammation during virus replication, assembly and release, and down regulation of interferon secretion and response thus delaying the activation of adaptive immunity. Serum neutralising antibody to the major capsid protein L1 usually develops after the induction of successful cell mediated immunity and these antibody and cell mediated responses are protective against subsequent viral challenge in natural infections in animals. Prophylactic vaccines consisting of HPV L1 VLPs generate high anti L1 serum neutralizing antibody concentrations and in clinical trials have shown greater than 95 per cent efficacy against both benign and neoplastic genital HPV associated disease. These vaccines are delivered intramuscularly and therefore circumvent the immune evasion strategies of the virus.

Human papillomavirus infection, cancer & therapy

Infection with human papillomaviruses (HPVs) is a major public health burden worldwide and is associated with a variety of epithelial lesions, including benign warts and several types of anogenital tumours, particularly cervical carcinoma. From available data it is clear that members of the HPV family are important human pathogens. Prevention or elimination of these infections would not only benefit the numerous patients with benign lesions, but ultimately should reduce the incidence of cervical cancer and possibly other epithelial cancers as well. Although prophylactic vaccines to block genital HPV infection have become available, it is not certain if they would be of benefit to those already infected. Therefore, the enormous and growing population of infected individuals would benefit from papillomavirus-specific therapy. In this review, we will discuss the functions of the viral proteins that appear to be the most appropriate for the development of therapeutics aimed at the treatment of viral infection and virus-induced cancers.

Cervical cancer screening & HPV vaccination: a comprehensive approach to cervical cancer control

India with its highest share of global burden of cervical cancer has to implement a population based cervical cancer control program to reduce the number of deaths. There are new screening options available like visual inspection after acetic acid application (VIA) test, single visit approach to screening and treatment etc. Emergence of the two effective vaccines against human papillomavirus (HPV), the necessary cause of cervical cancer, has introduced a fresh lease of life to the cervical cancer control strategies. The current high cost of the vaccines is a major impediment to implement a vaccine-based primary prevention approach.

HPV & HPV vaccination: issues in developing countries

Cervical cancer is the second-most common cancer in women worldwide causing most cancer related deaths in women in developing countries including India. The most predominant etiological factor for cervical cancer is persistent infection of certain high-risk types of human papillomaviruses (HR-HPVs), while low-risk types are associated with benign cervical lesions and genital warts. In India, the most common (98%) oncogenic types are HPV types 16 and 18 with HPV 16 exclusively (80-90%) prevalent. Two recently developed virus-like particle (VLP) based prophylactic HPV vaccines, quadrivalent Gardasil (HPV 16/18/6/11) and Cervarix (HPV 16/18) offer great promise. Several other therapeutic vaccines are also in clinical trials and are yet to establish their efficacy. The use of already developed VLP vaccines in resource-poor regions is limited by several factors, most importantly the high cost of the vaccine. Therefore efforts are being made in India to develop cost-effective second-generation vaccines. Besides cost, there are several socio-cultural and ethical issues involved with the implementation of already developed vaccines including the acceptability of HPV vaccination by preadolescent girls and their parents in India.

HPV vaccination: the promise & problems

Four-fifths of the cervical cancer burden in the world is experienced in developing countries. HPV genotypes 16 and 18 account for 70 per cent of cervical cancers and currently available vaccines targeting these two types confer a high degree of protection against HPV 16/18 infection and related cervical precancerous lesions. However, widespread implementation of HPV vaccination programs are challenged by the unaffordable high costs of the vaccines and the lack of effective vaccine delivery platforms for sexually naïve girls. Other unresolved issues include long-term protection, cross-protection against HPV types not included in the vaccine and whether booster doses will be needed. Sensitivities associated with a vaccine preventing a sexually transmitted infection in girls, lack of awareness, public demand and political will, lack of coordination between cancer control, sexual and reproductive health and vaccine delivery services are additional challenges. Reduced costs, simple vaccine regimes and strengthening vaccine delivery platforms for adolescents should eventually facilitate HPV vaccine introduction in developing countries.