Human Papillomavirus L1 Protein Research Articles

Characterization and Structural Analysis of the Human Papilloma Virus L1 Protein in Iran

Characterization and Structural Analysis of the Human Papilloma Virus L1 Protein in Iran

Screening and identification of B cell epitope within the major capsid protein L1 of HPV 52, using monoclonal antibodies

The L1 protein of Human papillomavirus (HPV), the main capsid protein, induces the formation of neutralizing antibodies. In this study, HPV52 L1 protein was induced to be expressed. Monoclonal antibody (mAb) 6A7 against L1 protein were screened by cell fusion techniques. Western Blot and immunofluorescence assay (IFA) demonstrated the specificity of the mAb. The L1 protein was truncated for prokaryotic expression (N1∼N7) and Dot-ELISA showed that 6A7 recognized N3 (aa 200–350). The immunodominant regions were truncated again for expression, with 6A7 recognizing N6 (aa 251–305). The N6 proteins were further truncated and then were constructed an four-segment eukaryotic expression vector. IFA showed that 6A7 could recognize amino acid 262–279. Amino acid 262–279 was selected to be truncated into short peptides P1 and P2. Finally, Peptide-ELISA and Dot-ELISA showed that the epitope regions of mAb 6A7 were amino acid 262–273. The mAbs with defined epitopes can lay the foundation for the analysis of antigenic epitope characteristics and promote the development of epitope peptide vaccines.

A CRR2-Dependent sRNA Sequence Supports Papillomavirus Vaccine Expression in Tobacco Chloroplasts

Human papillomavirus (HPV) infection is the leading cause of cervical cancer, and vaccination with HPV L1 capsid proteins has been successful in controlling it. However, vaccination coverage is not universal, particularly in developing countries, where 80% of all cervical cancer cases occur. Cost-effective vaccination could be achieved by expressing the L1 protein in plants. Various efforts have been made to produce the L1 protein in plants, including attempts to express it in chloroplasts for high-yield performance. However, manipulating chloroplast gene expression requires complex and difficult-to-control expression elements. In recent years, a family of nuclear-encoded, chloroplast-targeted RNA-binding proteins, the pentatricopeptide repeat (PPR) proteins, were described as key regulators of chloroplast gene expression. For example, PPR proteins are used by plants to stabilize and translate chloroplast mRNAs. The objective is to demonstrate that a PPR target site can be used to drive HPV L1 expression in chloroplasts. To test our hypothesis, we used biolistic chloroplast transformation to establish tobacco lines that express two variants of the HPV L1 protein under the control of the target site of the PPR protein CHLORORESPIRATORY REDUCTION2 (CRR2). The transgenes were inserted into a dicistronic operon driven by the plastid rRNA promoter. To determine the effectiveness of the PPR target site for the expression of the HPV L1 protein in the chloroplasts, we analyzed the accumulation of the transgenic mRNA and its processing, as well as the accumulation of the L1 protein in the transgenic lines. We established homoplastomic lines carrying either the HPV18 L1 protein or an HPV16B Enterotoxin::L1 fusion protein. The latter line showed severe growth retardation and pigment loss, suggesting that the fusion protein is toxic to the chloroplasts. Despite the presence of dicistronic mRNAs, we observed very little accumulation of monocistronic transgenic mRNA and no significant increase in CRR2-associated small RNAs. Although both lines expressed the L1 protein, quantification using an external standard suggested that the amounts were low. Our results suggest that PPR binding sites can be used to drive vaccine expression in plant chloroplasts; however, the factors that modulate the effectiveness of target gene expression remain unclear. The identification of dozens of PPR binding sites through small RNA sequencing expands the set of expression elements available for high-value protein production in chloroplasts.

Scientific evaluation of alleged findings in HPV vaccines: Molecular mimicry and mouse models of vaccine-induced disease.

Cervical cancer is caused by infections of the human papillomavirus (HPV), which can be prevented by vaccinations. In Japan, although about 3000 people die of cervical cancer annually, the HPV vaccination rate has remained extremely low in the eligible population since many Japanese have been concerned that “diverse symptoms,” such as chronic pain, movement disorders, and cognitive impairment, may occur as adverse reactions after HPV vaccination. The concern has been raised by media coverage of the ongoing HPV vaccine lawsuits, in which the plaintiffs complained of their symptoms caused by HPV vaccination. The claims have been based on the alleged pathogenic findings in research articles on HPV vaccines, summarized in the document prepared by the plaintiffs' attorneys. We critically evaluated these articles, in which the authors proposed the following findings/hypothesis: (i) molecular mimicry between HPV L1 and human proteins leads to the production of cross‐reactive antibodies; and (ii) HPV vaccine injection in mice causes damage in the brain, a mouse model for HPV vaccine associated neuro‐immunopathic syndrome (HANS). We found that these hypotheses were based mainly on the findings from a few research groups and that all the articles had flaws in the method, result, or discussion sections. Our current evaluation should help better understand the validity of the findings, which have been often misunderstood as the truth by the general public. We propose to accumulate high‐quality data on potential adverse events following HPV vaccination and to continue critically evaluating them.

Construction, expression, and in vitro assembly of virus-like particles of L1 protein of human papillomavirus type 52 in Escherichia coli BL21 DE3

BackgroundA major discovery in human etiology recognized that cervical cancer is a consequence of an infection caused by some mucosatropic types of human papillomavirus (HPV). Since L1 protein of HPV is able to induce the formation of neutralizing antibodies, it becomes a protein target to develop HPV vaccines. Therefore, this study aims to obtain and analyze the expression of HPV subunit recombinant protein, namely L1 HPV 52 in E. coli BL21 DE3. The raw material used was L1 HPV 52 protein, while the synthetic gene, which is measured at 1473 bp in pD451-MR plasmid, was codon-optimized (ATUM) and successfully integrated into 5643 base pairs (bps) of pETSUMO. Bioinformatic studies were also conducted to analyze B cell epitope, T cell epitope, and immunogenicity prediction for L1HPV52 protein. ResultsThe pETSUMO-L1HPV52 construct was successfully obtained in a correct ligation size when it was cut with EcoRI. Digestion by EcoRI revealed a size of 5953 and 1160 bps for both TA cloning petSUMO vector and gene of interest, respectively. Furthermore, the right direction of construct pETSUMO-L1HPV52 was proven by PCR techniques using specific primer pairs then followed by sequencing, which shows 147 base pairs. Characterization of L1 HPV 52 by SDS-PAGE analysis confirms the presence of a protein band at a size of ~55 kDa with 6.12 mg/L of total protein concentration. Observation under by transmission electron microscope demonstrates the formation of VLP-L1 at a size between 30 and 40 nm in assembly buffer under the condition of pH 5.4. Based on bioinformatics studies, we found that there are three B cell epitopes (GFPDTSFYNPET, DYLQMASEPY, KEKFSADLDQFP) and four T cell epitopes (YLQMASEPY, PYGDSLFFF, DSLFFFLRR, MFVRHFFNR). Moreover, an immunogenicity study shows that among all the T cell epitopes, the one that has the highest affinity value is DSLFFFLRR for Indonesian HLAs. ConclusionRegarding the achievement on successful formation of L1 HPV52-VLPs, followed by some possibilities found from bioinformatics studies, this study suggests promising results for future development of L1 HPV type 52 vaccine in Indonesia.

Presence of HPV in prostate tissue from patients submitted to prostate biopsy

Prostate cancer (PCa) is the second most frequent cancer among men in the Western population. Infections, such as the one caused by the human papillomavirus (HPV), have been shown to promote inflammation that can lead to the appearance of neoplasms. This study aimed to verify the presence of HPV in neoplastic and non-neoplastic prostate tissue in patients undergoing prostate biopsy and its possible relationship with PCa. Prostate tissue fragments were collected by prostate biopsy and subjected to polymerase chain reaction with primers for the HPV L1 gene to identify the presence of the virus. Among 162 patients, 10 (6.2%) had HPV and in 152 (93.8%) HPV was not identified in prostate biopsies. HPV was detected in 7/95 (7.4%) of patients with PCa, in 2/55 (3.6%) of patients without PCa, and in no patient with an inconclusive diagnosis of PCa. There was no significant difference (p = 0.487) of HPV presence in the tissue of patients with PCa. There were no significant levels of HPV L1 protein in prostate tissue. The findings suggest the absence of HPV oncogenic activity in the prostate tissue of patients with PCa.

The Clinical Significance of HPV L1/PD-L1 Tests Combined with Colposcopy for Cervical Precancerous Lesions and Cervical Cancer

To explore the expression of human papilloma virus (HPV) L1 protein and programmed cell death ligand-1 (PD-L1) protein in cervical precancerous lesions and cervical cancer, to analyze the correlation between HPV L1 and PD-L1 expression tests combined with colposcopy and the occurrence and development of of cervical lesions, and to determine the significance of the combined examination for auxiliary differential diagnosis. 260 patients with high-risk HPV (HR-HPV) infection who were treated at West China Second University Hospital, Sichuan University from January, 2018 to January, 2020 were included in the study. 260 cervical cytology specimens were collected, of which 218 cervical histology specimens were collected, of which 202 cases underwent colposcopy. Among the 260 cervical cytology specimens, 40 were of cervical inflammatory cells, 40 were of low-grade squamous intraepithilia lesions (LSIL) with mild atypical hyperplasia, 80 were of high-grade squamous intraepithilia lesions (HSIL) with moderate and severe atypical hyperplasia, and 100 were of cervical carcinoma cells (CCC). Among the 218 cervical histology specimens, 15 were of chronic cervicitis tissue, 20 were of cervical intraepithelial neoplasia (CIN) 1, 32 were of CIN 2, 51 were of CIN 3, and 100 were of cervical cancer (CC). Among the 260 patients, 202 underwent colposcopy. Immunocytochemistry and immunohistochemistry were used to assess the expression of HPV L1 protein and PD-L1 protein, and real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) was used to assess the level of PD-L1 mRNA in chronic cervicitis tissues and CC. The sensitivity, specificity, positive predictive value and negative predictive value of HPV L1 and PD-L1 tests combined with colposcopy in the detection of cervical lesions were studied. ①In the cervical cytology group, the positive rate of HPV L1 expression was 82.50%, 57.50%, 11.25%, and 3.00% in cervical inflammatory cells, low-grade squamous intraepithilia lesions (LSIL), high-grade squamous intraepithilia lesions (HSIL) and CCC, respectively, showing decreasing levels of positive expression rate ( P<0.05). In the cervical histology group, the positive rate of HPV L1 expression was 86.67%, 65.00%, 34.38%, 11.76% and 4.00% in chronic cervicitis tissues, CIN 1 group, CIN 2 group, CIN 3 group and CC group, respectively, showing decreasing levels of positive expression ( P<0.05). ②In the cervical cytology group, the average positive expression scores of PD-L1 in the cervical inflammatory cells, LSIL group, HSIL group, and CCC group were 0.25±0.12, 1.05±0.67, 1.39±0.11 and 2.14±0.17, respectively, showing increasing levels of positive expression scores ( P<0.05). In the cervical histology group, the average positive expression scores of PD-L1 were 0.28±0.24, 1.21±0.79, 1.56±0.26, 1.80±0.24, and 2.10±0.19 in the chronic cervicitis tissue, CIN 1 group, CIN 2 group, CIN 3 group and CC group, respectively, showing increasing levels of positive expression scores ( P<0.05). The relative expression of PD-L1 mRNA in chronic cervicitis tissue and CC is 1.02±0.04 and 1.81±0.22, respectively ( P<0.05). ③The sensitivity and specificity of diagnosis of cervical tissue CIN2 and abovelesions, HPV L1 detection alone was 95.8%, 47.2%, PD-L1 detection alone was 96.5%, 32.8%, colposcopy alone was 77.5%, 70.8%, HPV L1/PD-L1 tests combined detection was 92.4%, 64.5%, HPV L1/PD-L1 detection combined colposcopy was 71.6% and 89.6%, respectively. The sensitivity and specificity of the HPV L1/PD-L1 combined test for the diagnosis of CIN3 and above cervical lesions were 71.9% and 86.1%, HPV L1/PD-L1 combined with colposcopy were 50.5% and 100.0%, respectively. The specificity of HPV L1/PD-L1 detection combined with colposcopy for CIN2 and above lesions is higher than that of HPV L1 detection alone, PD-L1 detection alone and colposcopy alone. HPV L1/PD-L1 detection combined with colposcopy detection for CIN3 and above lesions has an important auxiliary diagnostic value.

Toll-like Receptor 9 Agonists in HPV Vaccine Gardasil9

Gardasil9 is a recombinant human papillomavirus (HPV) 9-valent vaccine, containing purified major capsid L1 protein of HPV types 6, 11, 16, 18, 31, 33, 45, 52, and 58 re-assembled into virus-like particles (VLPs) as the active ingredients. Since the antigens are purified recombinant proteins, in theory Gardasil9 needs a potent adjuvant to generate high and sustained levels of antibodies. Historically, amorphous aluminum hydroxyphosphate sulfate (AAHS), listed as the adjuvant for Gardasil9, was known to require one or more Toll-like receptor agonists, such as the phospholipids in the recombinant hepatitis B vaccine, Recombivax HB®. However, there are no phospholipids in the purified HPV L1 proteins or in Gardasil9. But the Food and Drug Administration (FDA) reports that Gardasil4 does contain recombinant HPV L1-specific DNA fragments, and they may serve as Toll-like receptor 9 agonists in Gardasil9. The author has tested 5 samples of Gardasil9 from 4 manufacturing lots by PCR amplification with a set of degenerate primers followed by heminested PCR or by another 5 sets of non-degenerate nested PCR primers in an attempt to detect all 9 vaccine-relevant HPV type-specific L1 gene DNAs bound to AAHS in the vaccine. Sanger sequencing confirmed the presence of HPV 18, 11, 16 and 6 L1 gene DNA bound to insoluble AAHS nanoparticles, but they were unevenly distributed even within the same vaccine sample. Also, these fragments were at least partially in non-B conformations. Since no L1 gene DNA of HPV 31, 33, 45, 52, and 58 was amplified by the commonly used degenerate PCR primers, the results suggest that these may all be in non-B conformations or may have been removed as contaminants by a purification protocol. Further research is warranted to standardize the HPV DNA fragments in Gardasil which are known to be potent Toll-like receptor 9 agonists.

Obtaining an immunoaffinity monolithic material: poly(GMA-co-EDMA) functionalized with an HPV-derived peptide using a thiol-maleimide reaction.

Metabolites have great potential for the design of biomarkers, since their presence or absence provides valuable information about a biological system. In this context, polyclonal antibodies are important metabolites for diagnostic procedures, but in some pathologies, it has been found that these metabolites are present at low concentrations, so it could be difficult to detect them. In this investigation, an organic monolithic material of poly(GMA-co-EDMA) was functionalized with a peptide via Michael addition (thiol–maleimide) click chemistry. The peptide, covalently bound to the monolith, contains the SPINNTKPHEAR sequence derived from the human papilloma virus L1 protein. It was determined that the obtained monolithic support allows selectively isolating polyclonal antibodies against the SPINNTKPHEAR sequence, since they are retained on the chemical surface of the material by an immunoaffinity interaction. The monolithic material functionalization protocol reported here could be applied to incorporate any peptide with a terminal cysteine in order to recover a specific analyte. A new method was developed for isolating and pre-concentrating antibodies using monolithic materials, which could contribute to the improvement of disease detection strategies based on immunoaffinity interactions.

Competitive Adsorption on Nanomaterials for Human Papillomavirus 16 L1 Protein Sensitive Detection

Human papillomavirus (HPV) L1 protein is a biomarker of HPV infection. The identification of HPV L1 protein provides valuable information regarding the viral infection status, reflect the status of HPV virus replication in cervical cells, and help understand cervical lesions Fade and progress. Graphene oxide is an important nanomaterial. Owing to the optical properties of graphene oxide (GO) itself and the interaction between GO and HPV16 L1 nucleic acid aptamer, we established a method for quantitative detection of HPV16 L1 protein by UV absorption spectrophotometry. The recovery rate of the method is 87%–102%, and the limit of detection is 2 pg/mL. We analyzed the HPV16 L1 protein quantitatively in clinical samples by adopting this method. The current method is simple and has promising reliability and profound sensitivity.

Toll-like Receptor 9 Agonists in HPV Vaccine Gardasil9

Gardasil9 is a recombinant human papillomavirus (HPV) 9-valent vaccine, containing purified major capsid L1 protein of HPV types 6, 11, 16, 18, 31, 33, 45, 52, and 58 re-assembled into virus-like particles (VLPs) as the active ingredients. Since the antigens are purified recombinant proteins, in theory Gardasil9 needs a potent adjuvant to generate high and sustained levels of antibodies. Historically, amorphous aluminum hydroxyphosphate sulfate (AAHS), listed as the adjuvant for Gardasil9, was known to require one or more Toll-like receptor agonists, such as the phospholipids in the recombinant hepatitis B vaccine, Recombivax HB®. However, there are no phospholipids in the purified HPV L1 proteins or in Gardasil9. But the Food and Drug Administration (FDA) reports that Gardasil4 does contain recombinant HPV L1-specific DNA fragments, and they may serve as Toll-like receptor 9 agonists in Gardasil9. The author has tested 5 samples of Gardasil9 from 4 manufacturing lots by PCR amplification with a set of degenerate primers followed by heminested PCR or by another 5 sets of non-degenerate nested PCR primers in an attempt to detect all 9 vaccine-relevant HPV type-specific L1 gene DNAs bound to AAHS in the vaccine. Sanger sequencing confirmed the presence of HPV 18, 11, 16 and 6 L1 gene DNA bound to insoluble AAHS nanoparticles, but they were unevenly distributed even within the same vaccine sample. Also, these fragments were at least partially in non-B conformations. Since no L1 gene DNA of HPV 31, 33, 45, 52, and 58 was amplified by the commonly used degenerate PCR primers, the results suggest that these may all be in non-B conformations or may have been removed as contaminants by a purification protocol. Further research is warranted to standardize the HPV DNA fragments in Gardasil which are known to be potent Toll-like receptor 9 agonists.

HPV Infection Affects Human Sperm Functionality by Inhibition of Aquaporin-8.

Human sperm cells express different aquaporins (AQPs), AQP3, 7, 8, 11, which are localized both in the plasma membrane and in intracellular structures. Besides cell volume regulation and end stage of cytoplasm removal during sperm maturation, the role of AQPs extends also to reactive oxygen species (ROS) elimination. Moreover, oxidative stress has been shown to inhibit AQP-mediated H2O2 permeability. A decrease in AQPs functionality is related to a decrease in sperm cells number and motility. Here we investigate the possible effect of human Papillomavirus (HPV) on both expression and function of AQPs in human sperm cells of patients undergoing infertility couple evaluation. Stopped-flow light-scattering experiments demonstrated that HPV infection heavily reduced water permeability of sperm cells in normospermic samples. Confocal immunofluorescence experiments showed a colocalization of HPV L1 protein with AQP8 (Pearson’s correlation coefficient of 0.61), confirmed by co-immunoprecipitation experiments. No interaction of HPV with AQP3 and AQP7 was observed. A 3D model simulation of L1 protein and AQP8 interaction was also performed. Present findings may suggest that HPV infection directly inhibits AQP8 functionality and probably makes sperm cells more sensitive to oxidative stress.

The possible regions to design Human Papilloma Viruses vaccine in Iranian L1 protein.

Human Papilloma Virus (HPV) genome encodes several proteins, as L1is major capsid protein and L2 is minor capsid protein. Among all HPV types HPV-16 and HPV-18 are the most common high-risk HPV (HR-HPV) types globally and the majority of cases are infected with these types. HPV entry and the initial interaction with the host cell are mainly related to the L1 protein which is the main component of HPV vaccines. The aim of this research was comparison analysis among all Iranian L1 protein sequences submitted in NCBI GenBank to find the major substitutions as well as structural and immune properties of this protein. All sequences HPV L1 protein from Iranian isolates from 2014 to 2016 were selected and obtained from NCBI data bank. “CLC Genomics Workbench” was used to translate alignment. To predict B cell epitopes, we employed several programs. Modification sites such as phosphorylation, glycosylation, and disulfide bonds were determined. Secondary and tertiary structures of all sequences were analyzed. Several mutations were found and major mutations were in amino acid residues 102, 202, 207, 292, 379, and 502. The mentioned mutations showed the minor effect on B cell and physicochemical properties of the L1 protein. Six disulfide bonds were determined in L1 protein and also in several N-link glycosylation and phosphorylation sites. Five L1 loops were determined, which had great potential to be B cell epitopes with high antigenic properties. All in all, this research as the first report from Iran described the tremendous potential of two L1 loops (BC and FG) to induce immune system which can be used as the descent candidate to design a new vaccine against HPV in the Iranian population. In addition, some differences between the reference sequence and Iranian patients’ sequences were determined. It is essential to consider these differences to monitor the effectiveness and efficacy of the vaccine for the Iranian population. Our results provide a vast understanding of L1 protein that can be useful for further studies on HPV infections and new vaccine generations.

Expression of human papillomavirus L1 protein and NuMA1 at cervical intraepithelial neoplasia

Relevance. Cervical cancer – one of malignant new growths most often met among women. Intraepithelial changes precede to it; these changes can disappear spontaneously or progress to cancer. For the present moment, there are no markers describing the outcome of cervical intraepithelial neoplasia.The objective was to research the expression L1 HPV and NuMA1 as factors of prognosis HPV-positive cervical intraepithelial neoplasias by high-risk human papillomavirus.Material and methods. The biopsies of 178 women from HPV-positive cervical neoplasias were studied by cytological, histological, immunocytochemical methods and PCR.Results. We verified HPV-HR-positive: mild (42.7 %), moderate (34.27 %), severe (21.91 %) dysplasias, Ca in situ (1.12 %). In 81.13 % of researches, CIN with expression of L1 and NuMA1 had regression of dysplasia, in 13.21 % – persistence of grade squamous intraepithelial lesion, in 5.66 % – progression of dysplasia. In 73.33 % of cases, CIN with expression of NuMA1 had regression, in 26.67 % – persistence of dysplasia. In 45.45 % of researches, CIN with expression of L1 had regression of dysplasia, in 48.48 % – persistence of grade squamous intraepithelial lesion, in 6.06 % – progression of dysplasia. Regression or progression of dysplasia with expression L1 and NuMA1 or one of these proteins for the first time was revealed later 6 months.Conclusion. CIN could come to the end with regression, persistence or progression. At expression of atypical cells L1 and NuMA1, the greatest quantity – 81.13 %, of cases of CIN regression was noted. At expression of atypical cells only NuMA1, CIN came to the end with regression or long persistence. Course of CIN with expression L1 HPV was characterized by the greatest parameters of persistence and progression marked, accordingly, in 48.48 and 6.06 % of cases.

The Underlying Mechanism of 3-Hydroxyphthalic Anhydride-Modified Bovine Beta-Lactoglobulin to Block Human Papillomavirus Entry Into the Host Cell.

We have previously demonstrated that 3-hydroxyphthalic anhydride (3HP)-modified bovine beta-lactoglobulin (3HP-β-LG) is highly effective in inhibiting entry of pseudovirus (PsV) of high- and low-risk human papillomavirus (HPV) into the target cell. Intravaginally applied 3HP-β-LG-containing vaginal gel could significantly inhibit HPV infection and reduce viral load in the cervical region. However, we still do not understand the underlying molecular mechanism by which 3HP-β-LG is able to inhibit HPV infection. Here, though, we showed that 3HP-β-LG did not inactivate HPV PsV, but rather blocked entry of HPV PsV into the target cell via its interaction with virus, not cell. It bound to the positively charged region in the HPV L1 protein, suggesting that 3HP-β-LG binds to HPV L1 protein through the interaction between the negatively charged region in 3HP-β-LG and the positively charged region in HPV L1 protein, thus competitively blocking the binding of HPV to the receptor on the basement membrane in vaginal mucosa. Although 3HP-modified chicken ovalbumin (3HP-OVA) also carries high net negative charges, it exhibited no anti-HPV activity, suggesting that the interaction between 3HP-modified protein and HPV L1 protein relies on both electrostatic and matchable conformation of the binding sites in both proteins. When topically applied, 3HP-β-LG did not enter the host cell or blood circulation. These findings suggest that 3HP-β-LG targets HPV L1 protein and blocks HPV entry into the host cell, thus being safe and effective for topical application in the treatment of HPV infection.

Cricket paralysis virus internal ribosome entry site-derived RNA promotes conventional vaccine efficacy by enhancing a balanced Th1/Th2 response

An ideal adjuvant should increase vaccine efficacy through balanced Th1/Th2 responses and be safe to use. Recombinant protein-based vaccines are usually formulated with aluminum (alum)-based adjuvants to ensure an adequate immune response. However, use of alum triggers a Th2-biased immune induction, and hence is not optimal. Although the adjuvanticity of RNA has been reported, a systematic and overall investigation on its efficacy is lacking. We found that single strand RNA (termed RNA adjuvant) derived from cricket paralysis virus intergenic region internal ribosome entry site induced the expression of various adjuvant-function-related genes, such as type 1 and 2 interferon (IFN) and toll-like receptor (TLR), T cell activation, and leukocyte chemotaxis in human peripheral blood mononuclear cells; furthermore, its innate and IFN transcriptome profile patterns were similar to those of a live-attenuated yellow fever vaccine. This suggests that protein-based vaccines formulated using RNA adjuvant function as live-attenuated vaccines. Application of the RNA adjuvant in mouse enhanced the efficacy of Middle East respiratory syndrome spike protein, a protein-subunit vaccine and human papillomavirus L1 protein, a virus-like particle vaccine, by activating innate immune response through TLR7 and enhancing pAPC chemotaxis, leading to a balanced Th1/Th2 responses. Moreover, the combination of alum and the RNA adjuvant synergistically induced humoral and cellular immune responses and endowed long-term immunity. Therefore, RNA adjuvants have broad applicability and can be used with all conventional vaccines to improve vaccine efficacy qualitatively and quantitively.

Induction of neutralizing antibodies by human papillomavirus vaccine generated in mammalian cells.

ABSTRACTBackgroundCervical cancer caused by human papillomavirus (HPV) infections is one of the most common cancers affecting women worldwide. Current preventative HPV vaccines on the market are composed of HPV L1 protein produced either in the yeast such as Gardasil or in the insect cells such as Cervarix. The duration of efficacy and cross-protection remain highly desirable for the improvement of current prophylactic HPV vaccine. Given that HPV carries out infection and replicates in mammalian cells, L2 protein, which is not included in the current licensed vaccines, is included in the third generation of HPV vaccine in pursuing of providing broader prevention. We hypothesize that a virus-like particle (VLP) consisting of HPV L1 plus L2 proteins generated in mammalian cells will present conformations more closely to native HPV, thus it will provide more durable and broader efficacy of prevention.MethodsWe took advantage of 293TT cells to produce VLP containing L1 and L2 proteins of HPV16 and HPV18, respectively.ResultsVLP particles of uniformed size and morphology were observed, and potent and broadly neutralizing antibodies were induced in mice and rabbits. In addition, compared to bivalent HPV vaccine of Cervarix, our HPV L1-L2 VLPs elicited higher titer of anti-sera, and the anti-sera also presented comparable neutralization potency against HPV16 and HPV18 infections even a much less potent adjuvant was used in our case.ConclusionOur VLPs were capable of eliciting stronger and more broadly neutralizing activities against various HPV subtypes and were potential candidate HPV vaccines.

Human papillomavirus DNA, HPV L1 capsid protein and p16INK4a protein as markers to predict cervical lesion progression.

Cervical cancer is the most common malignant tumors in women leading to serious morbidity and mortality worldwide, especially among developing countries. A main cause of the disease is the high-risk human papillomavirus (HR-HPV) infection. HSIL usually progress to cervical cancer, and low-grade lesions, including LSIL and ASCUS, mostly turn to normal or benign lesions, but there are still a small number of patients who will progress to HSIL. Up to now there is no efficient biomarker clinically available to predict people with high risk to progress into HSIL. This study was conducted to evaluate the value of human papillomavirus (HPV) DNA, p16INK4a protein, and HPV L1 capsid protein in predicting HSIL and minimizing unnecessary colposcopy treatments. 1222 patients with HR-HPV infection or with abnormal Thinprep cytologic test (TCT) were chosen to conduct colposcopy in the cervical out-patient clinic of Shanghai First Maternity and Infant Hospital affiliated to Shanghai Tongji University from June 2014 to January 2017. TCT, cervical biopsy, HPV DNA and HPVL1 were performed on all patients. 110 patients were selected to detect p16INK4a protein. Hybrid capture 2 (HC-2) was used to detect HPV DNA, and their subgroups using gene typing system. Immunohistochemical technology was used to detect HPV L1 and p16. HPV DNA was positive in 1097 cases, with the positive rate of 89.7% (1097/1222). In particular, the positive expression rates of HPV DNA were 82.3, 95.7, 96.6 and 100% in Normal/CC, LSIL, HSIL and cervical cancer groups, respectively (p < 0.001). HPV L1 was negative in 781 cases with HR-HPV infection, and the overall negative rate is 71.1%. In patients with Normal/CC, LSIL and HSIL, the negative expression rates of HPV L1 were 91.3, 40 and 81.2%, respectively (p value < 0.001). In the 110 patients, HPV L1 was negative in 98.1% (53/54) of Normal/CC, 42.9% (12/28) of LSIL and 85.1% (23/27) of HSIL (p value = 0.0043). P16-positive rates in patients with Normal/CC, LSIL and HSIL were 33.3% (18/54), 75% (21/28) and 96.2% (26/27), respectively (p value < 0.001). 18 out of 28 cases express low positive (+) in LSIL, 25 out of 27 cases express strong positive (3+) in HSIL. Patients with L1(-)p16(+) including 18.5% (10/54) of normal/cervicitis, 60.7% (17/28) of LSIL and 85.1% (23/27) of HSIL (p value < 0.005). Furthermore, patients with L1(-)p16(1+) included 37% (10/27) of normal/cervicitis 59.3% (16/27) of LSIL and 3.7% (1/27) of HSIL; patients with L1(-)p16(2+) consisted of 0% of normal/cervicitis/LSIL and 100% (1/1) of HSIL; patients with L1(-)p16(3+) were composed of 0% of normal/cervicitis, 4.5% (1/22) of LSIL and 95.5% (21/22) of HSIL (p value < 0.005) (Table6). With the increase in the degree of the cervical lesions, the expression of HPV DNA and p16 is up-regulated while HPV L1 protein is down-regulated. HPV DNA, HPV L1 and p16 are useful markers for the prediction of HSIL. Combined detection of these three markers has important potential to predicting HSIL and minimizing unnecessary colposcope examination.

Astaxanthin Prevents Human Papillomavirus L1 Protein Binding in Human Sperm Membranes.

Astaxanthin (Asta), red pigment of the carotenoid family, is known for its anti-oxidant, anti-cancer, anti-diabetic, and anti-inflammatory properties. In this study, we evaluated the effects of Asta on isolated human sperm in the presence of human papillomavirus (HPV) 16 capsid protein, L1. Sperm, purified by gradient separation, were treated with HPV16-L1 in both a dose and time-dependent manner in the absence or presence of 30 min-Asta pre-incubation. Effects of HPV16-L1 alone after Asta pre-incubation were evaluated by rafts (CTB) and Lyn dislocation, Tyr-phosphorylation (Tyr-P) of the head, percentages of acrosome-reacted cells (ARC) and endogenous reactive oxygen species (ROS) generation. Sperm membranes were also analyzed for the HPV16-L1 content. Results show that HPV16-L1 drastically reduced membrane rearrangement with percentage of sperm showing head CTB and Lyn displacement decreasing from 72% to 15.8%, and from 63.1% to 13.9%, respectively. Accordingly, both Tyr-P of the head and ARC decreased from 68.4% to 10.2%, and from 65.7% to 14.6%, respectively. Asta pre-incubation prevented this drop and restored values of the percentage of ARC up to 40.8%. No alteration was found in either the ROS generation curve or sperm motility. In conclusion, Asta is able to preserve sperm by reducing the amount of HPV16-L1 bound onto membranes.

N-terminal truncations on L1 proteins of human papillomaviruses promote their soluble expression in Escherichia coli and self-assembly in vitro

Human papillomavirus (HPV) is the causative agent in genital warts and nearly all cervical, anogenital, and oropharyngeal cancers. Nine HPV types (6, 11, 16, 18, 31, 33, 45, 52, and 58) are associated with about 90% of cervical cancers and 90% of genital warts. HPV neutralization by vaccine-elicited neutralizing antibodies can block viral infection and prevent HPV-associated diseases. However, there is only one commercially available HPV vaccine, Gardasil 9, produced from Saccharomyces cerevisiae that covers all nine types, raising the need for microbial production of broad-spectrum HPV vaccines. Here, we investigated whether N-terminal truncations of the major HPV capsid proteins L1, improve their soluble expression in Escherichia coli. We found that N-terminal truncations promoted the soluble expression of HPV 33 (truncated by 10 amino acids [aa]), 52 (15 aa), and 58 (10 aa). The resultant HPV L1 proteins were purified in pentamer form and extensively characterized with biochemical, biophysical, and immunochemical methods. The pentamers self-assembled into virus-like particles (VLPs) in vitro, and 3D cryo-EM reconstructions revealed that all formed T = 7 icosahedral particles having 50–60-nm diameters. Moreover, we formulated a nine-valent HPV vaccine candidate with aluminum adjuvant and L1 VLPs from four genotypes used in this study and five from previous work. Immunogenicity assays in mice and non-human primates indicated that this HPV nine-valent vaccine candidate elicits neutralizing antibody titers comparable to those induced by Gardasil 9. Our study provides a method for producing a nine-valent HPV vaccine in E. coli and may inform strategies for the soluble expression of other vaccine candidates.