Advantages and Disadvantages of Current Prophylactic Vaccines Against HPV

Current status and future directions for the development of human papillomavirus vaccines

The development of human papillomavirus (HPV) vaccines has made substantive progress, as represented by the approval of five prophylactic vaccines since 2006. Generally, the deployment of prophylactic HPV vaccines is effective in preventing newly acquired infections and incidences of HPV-related malignancies. However, there is still a long way to go regarding the prevention of all HPV infections and the eradication of established HPV infections, as well as the subsequent progression to cancer. Optimizing prophylactic HPV vaccines by incorporating L1 proteins from more HPV subtypes, exploring adjuvants that reinforce cellular immune responses to eradicate HPV-infected cells, and developing therapeutic HPV vaccines used either alone or in combination with other cancer therapeutic modalities might bring about a new era getting closer to the vision to get rid of HPV infection and related diseases. Herein, we summarize strategies for the development of HPV vaccines, both prophylactic and therapeutic, with an emphasis on the selection of antigens and adjuvants, as well as implications for vaccine efficacy based on preclinical studies and clinical trials. Additionally, we outline current cutting-edge insights on formulation strategies, dosing schedules, and age expansion among HPV vaccine recipients, which might play important roles in addressing barriers to vaccine uptake, such as vaccine hesitancy and vaccine availability.

Advancements in mRNA Vaccines: A Promising Approach for Combating Human Papillomavirus-Related Cancers

The human papillomavirus (HPV) is a typical sexually transmitted disease that affects different epithelial cells and can cause a number of health problems. HPV is mainly spread through sexual contact and is extremely contagious, even in the absence of obvious symptoms. It is linked to a number of malignancies, such as oropharyngeal, cervical, anal, vulvar, vaginal, and cutaneous as well as anogenital and cutaneous warts. Different vaccines targeting various HPV virus strains have been produced to prevent HPV infections. Vaccines can help prevent HPV-related illnesses, but they cannot cure malignancies that have already been caused by HPV. But new developments in mRNA vaccines have shown potential in combating malignancies linked to HPV. mRNA vaccines stimulate the immune system to identify and attack particular proteins present in viruses or tumour cells. The efficacy of mRNA vaccines in preventing HPV-related malignancies has been shown in preliminary experiments in mice. Additionally, in clinical trials aimed at individuals with HPV-related head and neck malignancies, personalised mRNA vaccines in combination with immune checkpoint drugs have demonstrated encouraging results. Even though mRNA vaccines have drawbacks and restrictions such as immunogenicity and instability, further research and development in this area has a great deal of promise for developing effective therapies for HPV-related malignancies.

COVID-19: Clinical status of vaccine development to date

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2)-induced COVID-19 is a complicated disease. Clinicians are continuously facing difficulties to treat infected patients using the principle of repurposing of drugs as no specific drugs are available to treat COVID-19. To minimize the severity and mortality, global vaccination is the only hope as a potential preventive measure. After a year-long global research and clinical struggle, 165 vaccine candidates have been developed and some are currently still in the pipeline. A total of 28 candidate vaccines have been approved for use and the remainder are in different phases of clinical trials. In this comprehensive report, the authors aim to demonstrate, classify and provide up-to-date clinical trial status of all the vaccines discovered to date and specifically focus on the approved candidates. Finally, the authors specifically focused on the vaccination of different types of medically distinct populations.

Designing of multi-epitope chimeric vaccine using immunoinformatic platform by targeting oncogenic strain HPV 16 and 18 against cervical cancer

Cervical cancer is the most common gynaecological cancer and reaches an alarming stage. HPVs are considered the main causative agents for cervical cancer and other sexually transmitted infections across the globe. Currently, three prophylactic vaccines are available against HPV infections with no therapeutic values. Due to a lack of effective therapeutic and prophylactic measures, the HPV infection is spreading in an uncontrolled manner. Next-generation of vaccine is needed to have both prophylactic and therapeutic values against HPV. Here first time we have designed a multi-epitope chimeric vaccine using the most oncogenic strain HPV 16 and HPV 18 through an immunoinformatic approach. In this study, we have used the L1, E5, E6 and E7 oncoproteins from both HPV 16 and HPV 18 strains for epitope prediction. Our recombinant chimeric vaccine construct consists, selected helper and cytotoxic T cell epitopes. Our computational analysis suggests that this chimeric construct is highly stable, non-toxic and also capable of inducing both cell-mediated and humoral immune responses. Furthermore, in silico cloning of the multi-epitope chimeric vaccine construct was done and the stabilization of the vaccine construct is validated with molecular dynamics simulation studies. Finally, our results indicated that our construct could be used for an effective prophylactic and therapeutic vaccine against HPV.

An Update on Human Papilloma Virus Vaccines: History, Types, Protection, and Efficacy

Human papillomavirus (HPV) is the most common sexually transmitted agent worldwide. Early prevention with HPV vaccination is a safe and effective method against this disease. HPV vaccines provided more protection against several oncogenic HPV strains. Three prophylactic HPV vaccines have been approved to target high-risk HPV types and protect against HPV-related disorders. These existing vaccines are based on the recombinant DNA technology and purified L1 protein that is assembled to form HPV empty shells. The prophylactic vaccines are highly immunogenic and can induce production of specific neutralizing antibodies. However, therapeutic vaccines are different from these prophylactic vaccines. They induced cell-mediated immunity against transformed cells, instead of neutralizing antibodies. The second generation of prophylactic HPV vaccines, made from alternative viral components using cost-effective production strategies, is undergoing clinical evaluation. The purpose of this review is to provide a complete and up-to-date review of the types of HPV vaccines and the efficiency of each of them for readers.

Peptide-Based Nanovaccines in the Treatment of Cervical Cancer: A Review of Recent Advances

Persistent infection with high-risk human papillomaviruses (HPVs), such as HPV-16 and HPV-18, can induce cervical cancer in humans. The disease carries high morbidity and mortality among females worldwide. Inoculation with prophylactic HPV vaccines, such as Gardasil^® or Cervarix^®, is the predominant method of preventing cervical cancer in females 6 to 26 years of age. However, despite the availability of commercial prophylactic HPV vaccines, no therapeutic HPV vaccines to eliminate existing HPV infections have been approved. Peptide-based vaccines, which form one of the most potent vaccine platforms, have been broadly investigated to overcome this shortcoming. Peptide-based vaccines are especially effective in inducing cellular immune responses and eradicating tumor cells when combined with nanoscale adjuvant particles and delivery systems. This review summarizes progress in the development of peptide-based nanovaccines against HPV infection.

In silico prediction of T-cell and B-cell epitopes of human papillomavirus type 16 L1 protein

Human papillomavirus type 16 (HPV-16) is one of the most important cause of developing cervical cancer. Therefore, effective epitope-based vaccine design for HPV-16 would be of major medical benefit. The aim of our study was to identify B- and T-cell epitopes of HPV-16 L1 protein. In this study, the HPV-16 L1 gene was isolated from HPV recovered from five vaginal swab samples using specific primers and finally sequenced. The ExPASy translate tool (http://web.expasy.org/translate/) was used to convert nucleotide sequence into amino acid sequence. Bioinformatic analysis was employed to predict suitable B- and T-cell epitopes and immunogenicity, allergenicity, and toxicity of predicted epitopes were then evaluated. Afterward, the selected T-cell epitopes were docked using Molegro Virtual Docker software. The two epitopes ₂₀₇ AMDFTTLQA₂₁₅ and ₂₀₀ MVDTGFGAM₂₀₈ have showed a very strong binding affinity to HLA-A0201 and HLA-B3501 molecules, respectively. Outcome of B-cell epitope prediction showed that epitope ₄₇₅ KAKPKFTLGKRK ATPTTSSTSTTAKRKK₅₀₂ contained overlapped epitope, which might be the epitope associated with the production of neutralizing antibody response. Based on this finding, the predicted B- and T-cell epitopes are promising targets for epitope-based vaccine development against HPV-16. Further in vivo and in vitro experiments are needed to confirm our findings.

Association of antibody to E2 protein of human papillomavirus and p16INK4A with progression of HPV-infected cervical lesions

Human papillomavirus (HPV) E2 and L1 proteins are expressed in cervical cells during the lytic stage of infection. Overexpression of p16^INK4A is a biomarker of HPV-associated cervical neoplasia. This study investigated antibodies to HPV16 E2, HPV16 L1, and p16^INK4A in sera from women with no squamous intraepithelial lesion (No-SIL) of the cervix, low-grade SIL, high-grade SIL, and cervical squamous cell carcinoma (SCC). HPV DNA was detected by polymerase chain reaction. Anti-E2, -L1, and -p16^INK4A antibodies in sera were determined by western blot. Among 116 samples, 69 (60%) were HPV DNA-positive. Percentages seropositive for anti-E2, -L1, and -p16^INK4A antibodies were 39.6, 22.4, and 23.3%, respectively. Anti-E2 antibody was significantly correlated with HPV DNA-positive cases. Eighty-seven women (75%) were regarded as infected with HPV, having at least one positive result from HPV DNA, L1, or E2 antibody. Antibody to p16^INK4A was associated with HPV infection (odds = 5.444, 95% CI 1.203-24.629, P = 0.028) and precancerous cervical lesions (odds = 5.132, 95% CI 1.604-16.415, P = 0.006). Interestingly, the concurrent detection of anti-E2 and -p16^INK4A antibodies was significantly associated with HPV infection (odds = 1.382, 95% CI 1.228-1.555, P = 0.044). These antibodies might be good candidate biomarkers for monitoring HPV-associated cervical lesion development to cancer.

Virus like particles as a platform for cancer vaccine development

Cancers have killed millions of people in human history and are still posing a serious health problem worldwide. Therefore, there is an urgent need for developing preventive and therapeutic cancer vaccines. Among various cancer vaccine development platforms, virus-like particles (VLPs) offer several advantages. VLPs are multimeric nanostructures with morphology resembling that of native viruses and are mainly composed of surface structural proteins of viruses but are devoid of viral genetic materials rendering them neither infective nor replicative. In addition, they can be engineered to display multiple, highly ordered heterologous epitopes or peptides in order to optimize the antigenicity and immunogenicity of the displayed entities. Like native viruses, specific epitopes displayed on VLPs can be taken up, processed, and presented by antigen-presenting cells to elicit potent specific humoral and cell-mediated immune responses. Several studies also indicated that VLPs could overcome the immunosuppressive state of the tumor microenvironment and break self-tolerance to elicit strong cytotoxic lymphocyte activity, which is crucial for both virus clearance and destruction of cancerous cells. Collectively, these unique characteristics of VLPs make them optimal cancer vaccine candidates. This review discusses current progress in the development of VLP-based cancer vaccines and some potential drawbacks of VLPs in cancer vaccine development. Extracellular vesicles with close resembling to viral particles are also discussed and compared with VLPs as a platform in cancer vaccine developments.

Intention of Mothers in Israel to Vaccinate their Sons against the Human Papilloma Virus

PURPOSE

This study investigated the intention of mothers in Israel to vaccinate their sons against HPV, using the Health Belief Model (HBM) as a framework, while comparing between Arab and Jewish mothers.

DESIGN AND METHODS

The study has a quantitative cross-sectional design. A convenience sample of 200 Jewish and Arab mothers of boys aged 5-18 completed a questionnaire based on the HBM.

RESULTS

The research findings indicate that only 14% of the mothers, constituting mostly Arab mothers, vaccinated their sons against HPV. Moreover, mothers showed a moderate level of intention to vaccinate their sons. This level was similar among Arab and Jewish mothers. However, the health beliefs of Jewish and Arab mothers differed. The HBM was found to explain 68% of mothers' intention to vaccinate their sons against HPV, and the perceived benefits of the vaccine were the factor most affecting this intention.

CONCLUSIONS

Although mothers' health beliefs concerning vaccinating their sons against HPV may vary between sectors, the HBM can be used to explain what motivates mothers to vaccinate their sons.

PRACTICE IMPLICATIONS

The research findings can assist in designing a national project among mothers of boys aimed at raising HPV vaccination rates, in both the Jewish and the Arab sector.

Potential opportunities to reduce cervical cancer by addressing risk factors other than HPV

Cervical cancer is the most common cancer in developing world and 80% of global burden is reported from these nations. Human papillomavirus along with poverty, illiteracy/lower education level and standards, multi-parity, tobacco, malnutrition and poor genital hygiene may act synergistically to cause cervical cancer. Risk factor of cervical cancer may in itself be the reason for non-viability of cervical cancer vaccine program in this part of the world. Interventions to address these risk factors in addition to vaccination of girls before their sexual debut may hold promises of reducing the morbidity and mortality of female genital cancers.

Development and impact of human papillomavirus vaccines

Cervical cancer is a global health crisis that disproportionately affects developing nations and underserved populations. Two vaccines targeting HPV-16 and 18, which account for 70% of invasive cervical carcinomas, are licensed in the United States and numerous countries worldwide. Both vaccine formulations have shown excellent efficacy with minimal toxicity. Numerous questions remain, including cost-effectiveness, vaccination of males, societal acceptance of HPV vaccination, and cervical dysplasia screening in the HPV-immunized population. Access to vaccination for underserved populations both in developed and resource-poor nations remains an issue. Multivalent vaccines that encompass additional oncogenic HPV strains are under development.

The choice of resin-bound ligand affects the structure and immunogenicity of column-purified human papillomavirus type 16 virus-like particles

Cell growth conditions and purification methods are important in determining biopharmaceutical activity. However, in studies aimed at manufacturing virus-like particles (VLPs) for the purpose of creating a prophylactic vaccine and antigen for human papillomavirus (HPV), the effects of the presence of a resin-bound ligand during purification have never been investigated. In this study, we compared the structural integrity and immunogenicity of two kinds of VLPs derived from HPV type 16 (HPV16 VLPs): one VLP was purified by heparin chromatography (hHPV16 VLP) and the other by cation-exchange chromatography (cHPV16 VLP). The reactivity of anti-HPV16 neutralizing monoclonal antibodies (H16.V5 and H16.E70) towards hHPV16 VLP were significantly higher than the observed cHPV16 VLP reactivities, implying that hHPV16 VLP possesses a greater number of neutralizing epitopes and has a greater potential to elicit anti-HPV16 neutralizing antibodies. After the application of heparin chromatography, HPV16 VLP has a higher affinity for H16.V5 and H16.E70. This result indicates that heparin chromatography is valuable in selecting functional HPV16 VLPs. In regard to VLP immunogenicity, the anti-HPV16 L1 IgG and neutralizing antibody levels elicited by immunizations of mice with hHPV16 VLPs were higher than those elicited by cHPV16 VLP with and without adjuvant. Therefore, the ability of hHPV16 VLP to elicit humoral immune responses was superior to that of cHPV16 VLP. We conclude that the specific chromatographic technique employed for the purification of HPV16 VLPs is an important factor in determining the structural characteristics and immunogenicity of column-purified VLPs.

A general protease digestion procedure for optimal protein sequence coverage and post-translational modifications analysis of recombinant glycoproteins: application to the characterization of human lysyl oxidase-like 2 glycosylation

Using recombinant DNA technology for expression of protein therapeutics is a maturing field of pharmaceutical research and development. As recombinant proteins are increasingly utilized as biotherapeutics, improved methodologies ensuring the characterization of post-translational modifications (PTMs) are needed. Typically, proteins prepared for PTM analysis are proteolytically digested and analyzed by mass spectrometry. To ensure full coverage of the PTMs on a given protein, one must obtain complete sequence coverage of the protein, which is often quite challenging. The objective of the research described here is to design a protocol that maximizes protein sequence coverage and enables detection of post-translational modifications, specifically N-linked glycosylation. To achieve this objective, a highly efficient proteolytic digest protocol using trypsin was designed by comparing the relative merits of denaturing agents (urea and Rapigest SF), reducing agents [dithiothreitol (DTT) and tris(2-carboxyethyl)phophine (TCEP)], and various concentrations of alkylating agent [iodoacetamide (IAM)]. After analysis of human apo-transferrin using various protease digestion protocols, ideal conditions were determined to contain 6 M urea for denaturation, 5 mM TCEP for reduction, 10 mM IAM for alkylation, and 10 mM DTT, to quench excess IAM before the addition of trypsin. This method was successfully applied to a novel recombinant protein, human lysyl oxidase-like 2. Furthermore, the glycosylation PTMs were readily detected at two glycosylation sites in the protein. These digestion conditions were specifically designed for PTM analysis of recombinant proteins and biotherapeutics, and the work described herein fills an unmet need in the growing field of biopharmaceutical analysis.

Simple and convenient chromatography-based methods for purifying the pseudovirus of human papillomavirus type 58

The currently available purification protocol for human papillomavirus (HPV) pseudovirus (PsV), as a substitute for the native HPV virion, utilizes Optiprep gradients (OG), which require costly equipment such as ultracentrifuges, and 4-7 h of working time, and cannot cope with large PsV samples. To develop a convenient method for purifying HPV type 58 PsV (HPV58 PsV) we have examined the use of heparin chromatography (HC) and cation-exchange chromatography (CC), which utilize open column systems and do not require expensive equipment. We confirmed that the PsVs resulting from HC and CC have correctly assembled conformations and are neutralized by anti-HPV58 PsV mouse serum, indicating that their antigenic characteristics make them suitable to substitute for native HPV58 virion. The recoveries of infectious PsV resulting from HC and CC were 39% and 11%, respectively, while that from OG was 58%. The two new purification methods are advantageous with respect to working time (only 30 min) and expense over the OG method, and have considerable potential for large scale purification.