Relationship between Humoral Immune Responses against HPV16, HPV18, HPV31 and HPV45 in 12-15 Year Old Girls Receiving Cervarix® or Gardasil® Vaccine

Safety and immunogenicity of a pichia pastoris-expressed bivalent human papillomavirus (types 16 and 18) L1 virus-like particle vaccine in healthy Chinese women aged 9-45 years: A randomized, double-blind, placebo-controlled phase 1 clinical trial

BACKGROUND

We evaluated the safety and immunogenicity of high and low doses of a novel pichia pastoris-expressed bivalent (types 16 and 18) human papillomavirus (HPV) virus-like particle vaccine.

METHODS

In this randomized, double-blind, placebo-controlled phase 1 trial, we enrolled 160 healthy females aged 9-45 years in Guangxi, China who were randomized (1:1:2) to receive either low (0.5 mL) or high (1.0 mL) dosages of bivalent HPV vaccine, or placebo (aluminum adjuvant) in a 0, 2, 6 months schedule. Adverse events and other significant conditions that occurred within 30 days after each vaccination were recorded throughout the trial. Sera were collected at days 0, 60, 180 and 210 to measure anti-HPV 16/18 neutralizing antibodies.

RESULTS

A total of 160 participants received at least one dose of the HPV vaccine and 152 completed the three dose vaccination series. Reporting rates of adverse events in placebo, low dose (0.5 mL) and high dose (1.0 mL) groups were 47.5 %, 55.0 % and 55.0 %, respectively. No serious adverse events occurred during this trial. 100 % of the participants who received three doses of the HPV vaccine produced neutralizing antibodies against HPV 16/18 vaccine. For HPV 16 and HPV 18, the geometric mean titers (GMTs) were similar between the low dose group (GMT_{HPV 16} = 10816 [95 % CI: 7824-14953]), GMT_{HPV 18} = 3966 [95 % CI: 2693-5841]) and high dose group (GMT _{HPV 16} = 14482 [95 % CI: 10848-19333], GMT _{HPV 18} = 3428 [95 % CI: 2533-4639]).

CONCLUSION

The pichia pastoris-expressed bivalent HPV vaccine was safe and immunogenic in Chinese females aged 9-45 years. The low dosage (0.5 mL) was selected for further immunogenicity and efficacy study.

Differences in HPV-specific antibody Fc-effector functions following Gardasil® and Cervarix® vaccination

Gardasil® (Merck) and Cervarix® (GlaxoSmithKline) both provide protection against infection with Human Papillomavirus 16 (HPV16) and Human Papillomavirus 18 (HPV18), that account for around 70% of cervical cancers. Both vaccines have been shown to induce high levels of neutralizing antibodies and are known to protect against progression beyond cervical intraepithelial neoplasia grade 2 (CIN2+), although Cervarix® has been linked to enhanced protection from progression. However, beyond the transmission-blocking activity of neutralizing antibodies against HPV, no clear correlate of protection has been defined that may explain persistent control and clearance elicited by HPV vaccines. Beyond blocking, antibodies contribute to antiviral activity via the recruitment of the cytotoxic and opsonophagocytic power of the immune system. Thus, here, we used systems serology to comprehensively profile Gardasil®- and Cervarix®- induced antibody subclass, isotype, Fc-receptor binding, and Fc-effector functions against the HPV16 and HPV18 major capsid protein (L1). Overall, both vaccines induced robust functional humoral immune responses against both HPV16 and HPV18. However, Cervarix® elicited higher IgG3 and antibody-dependent complement activating responses, and an overall more coordinated response between HPV16 and 18 compared to Gardasil®, potentially related to the distinct adjuvants delivered with the vaccines. Thus, these data point to robust Fc-effector functions induced by both Gardasil® and Cervarix®, albeit with enhanced coordination observed with Cervarix®, potentially underlying immunological correlates of post-infection control of HPV.

Differential Antibody Response against Conformational and Linear Epitopes of the L1 Proteins from Human Papillomavirus Types 16/18 Is Observed in Vaccinated Women or with Uterine Cervical Lesions

Antibodies against the Human Papillomavirus (HPV) L1 protein are associated with past infections and related to the evolution of the disease, whereas antibodies against L1 Virus-Like Particles (VLPs) are used to follow the neutralizing antibody response in vaccinated women. In this study, serum antibodies against conformational (VLPs) and linear epitopes of HPV16/18 L1 protein were assessed to distinguish HPV-vaccinated women from those naturally infected or those with uterine cervical lesions. The VLPs-16/18 were generated in baculovirus, and L1 proteins were obtained from denatured VLPs. Serum antibodies against VLPs and L1 proteins were evaluated by ELISA. The ELISA-VLPs and ELISA-L1 16/18 assays were validated with a vaccinated women group by ROC analysis and the regression analysis to distinguish the different populations of female patients. The anti-VLPs-16/18 and anti-L1-16/18 antibodies effectively detect vaccinated women (AUC = 1.0/0.79, and 0.94/0.84, respectively). The regression analysis showed that anti-VLPs-16/18 and anti-L1-16/18 antibodies were associated with the vaccinated group (OR = 2.11 × 10⁸/16.50 and 536.0/49.2, respectively). However, only the anti-L1-16 antibodies were associated with the high-grade lesions and cervical cancer (CIN3/CC) group (OR = 12.18). In conclusion, our results suggest that anti-VLPs-16/18 antibodies are effective and type-specific to detect HPV-vaccinated women, but anti-L1-16 antibodies better differentiate the CIN3/CC group. However, a larger population study is needed to validate these results.

Dry Formulation of Virus-Like Particles in Electrospun Nanofibers

Biologics can be combined with liquid polymer materials and electrospun to produce a dry nanofibrous scaffold. Unlike spray-drying and freeze-drying, electrospinning minimizes the physiological stress on sensitive materials, and nanofiber mat properties such as hydrophobicity, solubility, and melting temperature can be tuned based on the polymer composition. In this study, we explored the dry formulation of a virus-like particle (VLP) vaccine by electrospinning VLP derived from rabbit hemorrhagic disease virus modified to carry the MHC-I gp100 tumor-associated antigen epitope. VLP were added to a polyvinylpyrrolidone (PVP) solution (15% w/v) followed by electrospinning at 24 kV. Formation of a nanofibrous mat was confirmed by scanning electron microscopy, and the presence of VLP was confirmed by transmission electron microscopy and Western blot. VLP from the nanofibers induced T-cell activation and interferon- (IFN-) γ production in vitro. To confirm in vivo cytotoxicity, Pmel mice treated by injection with gp100 VLP from nanofibers induced a gp100 specific immune response, lysing approximately 65% of gp100-pulsed target cells, comparable to mice vaccinated with gp100 VLP in PBS. VLP from nanofibers also induced an antibody response. This work shows that electrospinning can be used to dry-formulate VLP, preserving both humoral and cell-mediated immunity.

Induction of cross-neutralizing antibodies by sequential immunization with heterologous papillomavirus L1VLPs and its implications for HPV prophylactic vaccines

Sequential immunization with antigens from different strains of HIV-1, influenza viruses or dengue viruses induced cross-neutralizing antibodies and enhanced the antibody responses against previous antigens. The characteristics of neutralizing antibodies induced by sequential immunization with different types of human papillomavirus (HPV) L1 virus-like particles (L1VLPs) are unclear. In this study, mice were primed with one or two types (HPV-16 or HPV16/18) of L1VLPs, then boosted sequentially with HPV6/18/45/11/31/58 or HPV6/45/11/31/58 L1VLPs, and sera were analyzed with HPV pseudovirus-based neutralization assay. The results showed that neutralizing activities against earlier immunized vaccine types were enhanced gradually by subsequent immunizations, and low levels of neutralizing activities against nonvaccine types (HPV33/35/52/59/68) were also observed. After absorbing the immune sera with vaccine-type (HPV16/18/45) L1VLPs, neutralizing activities against tested priming and boosting types (HPV16/18/58) decreased significantly, and that against nonvaccine type (HPV-33) was also partially eliminated. Moreover, neutralizing activities against vaccine types (HPV16/58) were significantly reduced after absorbing with nonvaccine-type VLPs (HPV33/52). These data suggest that cross-neutralizing epitopes exist among different HPV L1VLPs. The cross-neutralizing activities against nonvaccine types and the enhanced neutralizing activities against earlier immunized vaccine types may result from sequential boosting with these cross-neutralizing epitopes. These observations support early vaccination with more types of L1VLPs derived from HPVs that cause a serious threat to the population.

Prevalence of antibodies against a cyclic peptide mimicking the FG loop of the human papillomavirus type 16 capsid among Tunisian women

Background

In the past decade, cervical cancer has gone from being the second to the fourth most common cancer in women worldwide, but remains the second most common in developing countries. This cancer is most commonly caused by high-risk types of human papillomavirus (HPV), mainly type 16 (HPV16), which are sexually transmitted. This study aimed to investigate the usefulness of a cyclic synthetic peptide designed from the major L1 capsid protein of HPV16 for detecting anti-HPV16 antibodies.

Methods

We designed and synthetized a peptide that corresponds to the full sequence of the surface-exposed FG loop. We tested the antigenicity of the linear and the cyclic peptides against HPV16 L1 monoclonal antibodies. We used ELISA to detect anti-peptide antibodies in sera and cervical secretions of 179 Tunisian women, and we applied polymerase chain reaction and direct sequencing methods to detect and genotype HPV DNA.

Results

Both the linear and the cyclic peptides were recognized by the same neutralizing monoclonal antibodies, but the cyclic peptide was more reactive with human sera. The prevalence of the anti-peptide antibodies in sera was higher in women with low-grade squamous intraepithelial lesions (LGSIL) than in women with high-grade squamous intraepithelial lesions (HGSIL) (44% and 15%, respectively). This contrasts with HPV16 DNA prevalence. Compared to women from the general population, systemic IgG prevalence was significantly higher among sex workers (25%; P = 0.002) and women with LGSIL (44%; P = 0.001). In addition, systemic IgA and cervical IgG prevalence was higher among sex workers only (P = 0.002 and P = 0.001, respectively). We did not observe anti-peptide IgG antibodies in women with a current HPV16 infection.

Conclusion

Anti-peptide IgG in sera or in cervical secretions could be markers of an effective natural immunization against HPV16. This may open novel perspectives for monitoring vaccinated women and for the design of synthetic peptide-based vaccines.

Natural and vaccine-induced B cell-derived systemic and mucosal humoral immunity to human papillomavirus

Introduction: Human papillomavirus (HPV) are the causative agent of mucosal neoplasia. Both cervical, anal and oropharyngeal cancers incidence is constantly increasing, making the HPV infection, a significant worldwide concern. Together, the CD8+ T cytotoxic cell-mediated response and the HPV-specific antibody response control most of the HPV infections before the development of cancers.Areas covered: We searched the MEDLINE and EMBASE databases and identified 228 eligible studies from 1987 to 2019 which examines both naturally acquired and vaccine induced humoral immunity against HPV infection in female and male subjects from worldwide origin. Herein, we synthesize current knowledge on the features of systemic and mucosal humoral immunity against HPV. We discuss the issues of the balance between the viral clearance or the escape to the host immune response, the differences between natural and vaccine-induced HPV-specific antibodies and their neutralizing capability. We also discuss the protection afforded after natural infection or following prophylactic vaccination.Expert opinion: Understanding the antibody response induced by HPV infection has led to the design of first-generation prophylactic vaccines. Now, prophylactic vaccination induces protective and long-lasting antibody response which would also strengthened the natural moderate humoral response in people previously exposed to the virus.

HPV-Specific Systemic Antibody Responses and Memory B Cells are Independently Maintained up to 6 Years and in a Vaccine-Specific Manner Following Immunization with Cervarix and Gardasil in Adolescent and Young Adult Women in Vaccination Programs in Italy

Human papillomavirus (HPV) persistent infections are associated with cervical cancer and other HPV-related diseases and tumors. Thus, the characterization of long lasting immunity to currently available HPV vaccines is important. A total of 149 female subjects vaccinated with Cervarix or Gardasil participated to the study and they were stratified according to age (10–12-year-old and 16–20-year-old). Humoral immune responses (IgG and neutralizing antibody titers, antibody avidity) and circulating memory B cells were analyzed after an average of 4–6 years from the third immunization. The humoral responses against HPV-16 and HPV-18 (and HPV-6 and HPV-11 for Gardasil) were high in both age groups and vaccines up to six years from the third dose. However, Cervarix induced significantly higher and more persistent antibody responses, while the two vaccines were rather equivalent in inducing memory B cells against HPV-16 and HPV-18. Moreover, the percentage of subjects with vaccine-specific memory B cells was even superior among Gardasil vaccinees and, conversely, Cervarix vaccinated individuals with circulating antibodies, but undetectable memory B cells were found. Finally, a higher proportion of Cervarix-vaccinated subjects displayed cross-neutralizing responses against non-vaccine types HPV-31 and HPV-45. Gardasil and Cervarix may, thus, differently affect long-lasting humoral immunity from both the quantitative and qualitative point of view.

Selective Persistence of HPV Cross-Neutralising Antibodies following Reduced-Dose HPV Vaccine Schedules

The duration of cross-neutralising antibody responses (cross-NAb) following HPV immunisation is unknown. We compared cross-NAb responses in cohort of girls who were either unimmunised or had received immunisation with one, two or three doses of 4vHPV (Gardasil^®, Merck Inc., Kenilworth, NJ, USA) six years earlier, before and one month after a booster dose of 2vHPV (Cervarix^®, GSK, Brentford, UK). NAb to potentially cross-reactive HPV genotypes 31, 33, 45, 52 and 58 were measured using a HPV pseudovirion-based neutralisation assay. Girls who had previously received at least one dose of 4vHPV had significantly higher NAb titres for HPV31 when compared with unimmunised girls, whereas no difference in NAb titre was observed for four other genotypes (33, 45, 52 and 58). Following a single further immunisation with 2vHPV, NAb titres to each of the five tested HPV genotypes were comparable for girls who previously received one, two or three doses of 4vHPV, and were significantly higher than for previously unimmunised girls. Immunisation with one, two or three doses of 4vHPV induced NAb to HPV31 that persisted for six years, but there was no persistence of NAb to HPV33, 45, 52 or 58. Our results suggest that one or two doses of 4vHPV may provide long-term protection against HPV31.

Recombinant human papillomavirus nonavalent vaccine in the prevention of cancers caused by human papillomavirus

Human papillomavirus (HPV) types 16 and 18 cause 70% of cervical cancer cases globally. The nonavalent HPV vaccine (9vHPV) was licensed in 2014 and protects against the next five most common cancer-causing HPV types (HPV 31/33/45/52/58) after HPV 16/18. Phase III clinical studies have demonstrated high vaccine efficacy (>90%) against cervical, vulvar, and vaginal precancers caused by these additional types, and have shown comparable immunogenicity to the shared genotypes to quadrivalent HPV vaccine (4vHPV). Vaccine efficacy and antibody responses for 9vHPV are found to persist for at least five years while longer-term observational studies are ongoing to monitor long-term vaccine effectiveness. The implementation of 9vHPV has the potential to prevent up to 93% of cervical cancer cases, as well as a significant proportion of other HPV-related anogenital cancers. This review article summarizes the current evidence for 9vHPV in terms of vaccine efficacy against HPV infection and related anogenital precancers, safety, and immunogenicity, as well as discussing the potential impact of this vaccine on the cervical cancer burden globally.

Virus-Like Particles as an Instrument of Vaccine Production

The paper discusses the techniques which are currently implemented for vaccine production based on virus-like particles (VLPs). The factors which determine the characteristics of VLP monomers assembly are provided in detail. Analysis of the literature demonstrates that the development of the techniques of VLP production and immobilization of target antigens on their surface have led to the development of universal platforms which make it possible for virtually any known antigen to be exposed on the particle surface in a highly concentrated form. As a result, the focus of attention has shifted from the approaches to VLP production to the development of a precise interface between the organism's immune system and the peptides inducing a strong immune response to pathogens or the organism's own pathological cells. Immunome-specified methods for vaccine design and the prospects of immunoprophylaxis are discussed. Certain examples of vaccines against viral diseases and cancers are considered.

Correlates of GLA family adjuvants' activities

Lipopolysaccharide (LPS) is a well-defined agonist of Toll-like receptor (TLR) 4 that activates innate immune responses and influences the development of the adaptive response during infection with Gram-negative bacteria. Many years ago, Dr. Edgar Ribi separated the adjuvant activity of LPS from its toxic effects, an effort that led to the development of monophosphoryl lipid A (MPL). MPL, derived from Salmonella minnesota R595, has progressed through clinical development and is now used in various product-enabling formulations to support the generation of antigen-specific responses in several commercial and preclinical vaccines. We have generated several synthetic lipid A molecules, foremost glucopyranosyl lipid adjuvant (GLA) and second-generation lipid adjuvant (SLA), and have advanced these to clinical trial for various indications. In this review we summarize the potential and current positioning of TLR4-based adjuvant formulations in approved and emerging vaccines.

Immunogenicity of HPV prophylactic vaccines: Serology assays and their use in HPV vaccine evaluation and development

When administered as standard three-dose schedules, the licensed HPV prophylactic vaccines have demonstrated extraordinary immunogenicity and efficacy. We summarize the immunogenicity of these licensed vaccines and the most commonly used serology assays, with a focus on key considerations for one-dose vaccine schedules. Although immune correlates of protection against infection are not entirely clear, both preclinical and clinical evidence point to neutralizing antibodies as the principal mechanism of protection. Thus, immunogenicity assessments in vaccine trials have focused on measurements of antibody responses to the vaccine. Non-inferiority of antibody responses after two doses of HPV vaccines separated by 6 months has been demonstrated and this evidence supported the recent WHO recommendations for two-dose vaccination schedules in both boys and girls 9-14 years of age. There is also some evidence suggesting that one dose of HPV vaccines may provide protection similar to the currently recommended two-dose regimens but robust data on efficacy and immunogenicity of one-dose vaccine schedules are lacking. In addition, immunogenicity has been assessed and reported using different methods, precluding direct comparison of results between different studies and vaccines. New head-to-head vaccine trials evaluating one-dose immunogenicity and efficacy have been initiated and an increase in the number of trials relying on immunobridging is anticipated. Therefore, standardized measurement and reporting of immunogenicity for the up to nine HPV types targeted by the current vaccines is now critical. Building on previous HPV serology assay standardization and harmonization efforts initiated by the WHO HPV LabNet in 2006, new secondary standards, critical reference reagents and testing guidelines will be generated as part of a new partnership to facilitate harmonization of the immunogenicity testing in new HPV vaccine trials.

Human papillomavirus first and second generation vaccines-current status and future directions

It has been more than 10 years that the first prophylactic papillomavirus vaccine became available, although distribution has been mainly limited to the more affluent countries. The first two vaccines have been a great success, hundreds of millions of women and a much smaller number of men have been vaccinated ever since. In a few countries with high vaccination coverage, in particular Australia but also parts of Great Britain and others, clinical impact of vaccination programs is already visible and there are indications for herd immunity as well. Vaccine efficacy is higher than originally estimated and the vaccines have an excellent safety profile. Gardasil9 is a second generation HPV virus-like particle vaccine that was licensed in 2015 and there are more to come in the near future. Currently, burning questions in respect to HPV vaccination are the duration of protection - especially in regard to cross-protection - reduction of the three-dose regimen and its impact on cross-protection; and duration of response, as well as protection against oropharyngeal HPV infections. Furthermore, researchers are seeking to overcome limitations of the VLP vaccines, namely low thermal stability, cost, invasive administration, limited coverage of non-vaccine HPV types, and lack of therapeutic efficacy. In this review we summarize the current status of licensed VLP vaccines and address questions related to second and third generation HPV vaccines.

Recurrent respiratory papillomatosis (RRP)-time for a reckoning?

Objectives

Recurrent respiratory papillomatosis (RRP) is a rare disease, but one with severe morbidity and occasional mortality. The aetiological agent is human papillomavirus (HPV), and HPV types 6 and 11 account for over 90% of all cases. In the active phase of the disease, patients require multiple hospital admissions for surgical removal or ablation of these benign tumors, which are likely to obstruct the airways if left unchecked. Long‐term sequelae include scarring of the vocal cords, change in voice timbre, or even muteness if a tracheostomy is required. The aim of this study was to determine if adjuvant vaccination with the quadrivalent HPV L1 vaccine (Gardasil™) would decrease numbers of surgical treatments post‐vaccination.

Methods

A prospective pilot study following a cohort of 12 RRP patients, all of whom gave fully informed consent to participate. All patients had their papillomas typed and if they were found to have types 6 or 11, were vaccinated at the time of first surgical treatment in the hospital, according to the manufacturer's protocols. Patients were followed up closely with 3 or 6 month follow‐up visits. Standard surgical treatments were given and were not affected by whether they participated in the study.

Results

We found a >7‐fold decrease in the incidence rates of papillomatosis requiring surgical intervention from the pre‐vaccination period (47.44/1000 patient‐months) compared to the post‐vaccination period (6.71/1000 patient‐months).

Discussion

Surgical treatments for RRP are robust markers for papillomata which require treatment because of the dangers of obstruction of the airway. Despite the small size of this cohort (due to the rarity of this disease), the data suggests that adjuvant use of quadrivalent HPV L1 vaccine imparts significant benefit to this group of patients. A large multi‐center randomized placebo controlled trial is required to definitively establish whether this hypothesis is true and can become the new standard of therapy.

Level of Evidence

3b

HPV vaccines - A review of the first decade

Pre-adolescent girls (9-15years) have the option of receiving a two dose HPV vaccine series at either a six month or one year interval to provide protection from HPV 16, the most prevalent type associated with cervical cancers, as well as several other less prevalent types. This series of vaccinations is highly likely to protect her from HPV infection until she enters the routine screening program, whether that be primary HPV testing or a combination of HPV testing and cytology. The two dose program has been recommended by the World Health Organization (WHO) since 2015. For women 15years and older, the three dose vaccine schedule is still recommended. The past ten years of Gardasil use has provided evidence of reduced HPV 16/18 infections in countries where there has been high coverage. Gardasil9 has replaced Gardasil. Gardasil9 has the same rapid anti-HPV 18 and HPV45 titer loss as Gardasil did. Cervarix remains equivalent to Gardasil9 in the prevention of HPV infections and precancers of any HPV type; Cervarix also has demonstrated sustained high antibody titers for at least 10years. One dose of Cervarix provides protection against HPV 16/18 infection with robust antibody titers well above natural infection titers. This may offer the easiest and most cost effective vaccination program over time, especially in low and lower middle income countries. Cervical cancer screening must continue to control cancer incidence over the upcoming decades. Future studies of prophylactic HPV vaccines, as defined by the WHO, must demonstrate protection against six month type specific persistent infections, not actual cervical cancer precursor disease endpoints, such as cervical intraepithelial neoplasia grade 3 (CIN 3) or adenocarcinoma in situ (AIS). This simplifies and makes less expensive future comparative studies between existing and new generic vaccines.