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

Efficacy and Durability of Immune Response after Receipt of HPV Vaccines in People Living with HIV

People living with HIV (PLH) experience higher rates of HPV infection as well as an increased risk of HPV-related disease, including malignancies. Although they are considered a high-priority group for HPV vaccination, there are limited data regarding the long-term immunogenicity and efficacy of HPV vaccines in this population. Seroconversion rates and geometric mean titers elicited by vaccination are lower in PLH compared to immunocompetent participants, especially in individuals with CD4 counts below 200 cells/mm³ and a detectable viral load. The significance of these differences is still unclear, as a correlate of protection has not been identified. Few studies have focused on demonstrating vaccine efficacy in PLH, with variable results depending on the age at vaccination and baseline seropositivity. Although waning humoral immunity for HPV seems to be more rapid in this population, there is evidence that suggests that seropositivity lasts at least 2-4 years following vaccination. Further research is needed to determine the differences between vaccine formulations and the impact of administrating additional doses on durability of immune protection.

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.

Systems serology-based comparison of antibody effector functions induced by adjuvanted vaccines to guide vaccine design

The mechanisms by which antibodies confer protection vary across vaccines, ranging from simple neutralization to functions requiring innate immune recruitment via Fc-dependent mechanisms. The role of adjuvants in shaping the maturation of antibody-effector functions remains under investigated. Using systems serology, we compared adjuvants in licensed vaccines (AS01_B/AS01_E/AS03/AS04/Alum) combined with a model antigen. Antigen-naive adults received two adjuvanted immunizations followed by late revaccination with fractional-dosed non-adjuvanted antigen ( NCT00805389 ). A dichotomy in response quantities/qualities emerged post-dose 2 between AS01_B/AS01_E/AS03 and AS04/Alum, based on four features related to immunoglobulin titers or Fc-effector functions. AS01_B/E and AS03 induced similar robust responses that were boosted upon revaccination, suggesting that memory B-cell programming by the adjuvanted vaccinations dictated responses post non-adjuvanted boost. AS04 and Alum induced weaker responses, that were dissimilar with enhanced functionalities for AS04. Distinct adjuvant classes can be leveraged to tune antibody-effector functions, where selective vaccine formulation using adjuvants with different immunological properties may direct antigen-specific antibody functions.

Immunogenicity, safety, and efficacy of the HPV vaccines among people living with HIV: A systematic review and meta-analysis

Background

Vaccines have been demonstrated to protect against high-risk human papillomavirus infection (HPV), including HPV-16/18, and cervical lesions among HIV negative women. However, their efficacy remains uncertain for people living with HIV (PLHIV).We systematically reviewed available evidence on HPV vaccine on immunological, virological, or other biological outcomes in PLHIV.

Methods

We searched five electronic databases (PubMed, Medline and Embase, clinicaltrials.gov and the WHO clinical trial database) for longitudinal prospective studies reporting immunogenicity, virological, cytological, histological, clinical or safety endpoints following prophylactic HPV vaccination among PLHIV. We included studies published by February 11th, 2021. We summarized results, assessed study quality, and conducted meta-analysis and subgroup analyses, where possible.

Findings

We identified 43 publications stemming from 18 independent studies (Ns =18), evaluating the quadrivalent (Ns =15), bivalent (Ns =4) and nonavalent (Ns =1) vaccines. A high proportion seroconverted for the HPV vaccine types. Pooled proportion seropositive by 28 weeks following 3 doses with the bivalent, quadrivalent, and nonavalent vaccines were 0.99 (95% confidence interval: 0.95-1.00, Ns =1), 0.99 (0.98-1.00, Ns =9), and 1.00 (0.99-1.00, Ns =1) for HPV-16 and 0.99 (0.96-1.00, Ns =1), 0.94 (0.91-0.96, Ns =9), and 1.00 (0.99-1.00, Ns =1) for HPV-18, respectively. Seropositivity remained high among people who received 3 doses despite some declines in antibody titers and lower seropositivity over time, especially for HPV-18, for the quadrivalent than the bivalent vaccine, and for HIV positive than negative individuals. Seropositivity for HPV-18 at 29-99 weeks among PLHIV was 0.72 (0.66-0.79, Ns =8) and 0.96 (0.92-0.99, Ns =2) after 3 doses of the quadrivalent and bivalent vaccine, respectively and 0.94 (0.90-0.98, Ns =3) among HIV-negative historical controls. Evidence suggests that the seropositivity after vaccination declines over time but it can lasts at least 2-4 years. The vaccines were deemed safe among PLHIV with few serious adverse events. Evidence of HPV vaccine efficacy against acquisition of HPV infection and/or associated disease from the eight trials available was inconclusive due to the low quality.

Interpretation

PLHIV have a robust and safe immune response to HPV vaccination. Antibody titers and seropositivity rates decline over time but remain high. The lack of a formal correlate of protection and efficacy results preclude definitive conclusions on the clinical benefits. Nevertheless, given the burden of HPV disease in PLHIV, although the protection may be shorter or less robust against HPV-18, the robust immune response suggests that PLHIV may benefit from receiving HPV vaccination after acquiring HIV. Better quality studies are needed to demonstrate the clinical efficacy among PLHIV.

Funding

World Health Organization. MRC Centre for Global Infectious Disease Analysis, Canadian Institutes of Health Research, UK Medical Research Council (MRC).

Single-dose HPV vaccine immunity: is there a role for non-neutralizing antibodies?

A single dose of human papillomavirus (HPV) vaccine against HPV infection (prerequisite for cervical cancer) appears to be as efficacious as two or three doses, despite inducing lower antibody titers. Neutralizing antibodies are thought to be the primary mediator of protection, but the threshold for protection is unknown. Antibody functions beyond neutralization have not been explored for HPV vaccines. Here, we discuss the immune mechanisms of HPV vaccines, with a focus on non-neutralizing antibody effector functions. In the context of single-dose HPV vaccination where antibody is limiting, we propose that non-neutralizing antibody functions may contribute to preventing HPV infection. Understanding the immunological basis of protection for single-dose HPV vaccination will provide a rationale for implementing single-dose HPV vaccine regimens.

B Cell Responses upon Human Papillomavirus (HPV) Infection and Vaccination

Infection with human papillomavirus (HPV) is the necessary cause of cervical cancer. Availability of vaccines against HPV makes it a highly preventable disease. HPV vaccines act through type-specific neutralizing antibodies produced by antigen-specific plasma cells known as long-lived plasma cells (LLPC). However, just as any other vaccine, success of HPV vaccine is attributed to the immunologic memory that it builds, which is largely attained through generation and maintenance of a class of B cells named memory B cells (Bmem). Both LLPCs and Bmems are important in inducing and maintaining immune memory and it is therefore necessary to understand their role after HPV vaccination to better predict outcomes. This review summarizes current knowledge of B-cell responses following HPV vaccination and natural infection, including molecular signatures associated with these responses.

Effects of the age of vaccination on the humoral responses to a human papillomavirus vaccine

Adult vaccination programs are receiving increasing attention however, little is known regarding the impact of age on the maintenance of the immune response. We investigated this issue in the context of a human papillomavirus (HPV) vaccination program collecting real-world data on the durability of humoral immunity in 315 female subjects stratified according to vaccination age (adolescents and adults) and sampled at early or late time points after the last vaccine dose. HPV-specific IgGs, but not memory B cells, were induced and maintained at higher levels in subjects vaccinated during adolescence. Nonetheless, antibody functions waned over time to a similar degree in adolescents and adults. To shed light on this phenomena, we analyzed quantitative and qualitative properties of lymphocytes. Similar biochemical features were observed between B-cell subsets from individuals belonging to the two age groups. Long term humoral responses toward vaccines administered at an earlier age were comparably maintained between adolescents and adults. The percentages of naïve B and CD4+ T cells were significantly higher in adolescents, and the latter directly correlated with IgG titers against 3 out of 4 HPV types. Our results indicate that age-specific HPV vaccine responsiveness is mostly due to quantitative differences of immune cell precursors rather than qualitative defects in B cells. In addition, our results indicate that adults also have a good humoral immunogenic profile, suggesting that their inclusion in catch-up programmes is desirable.

LncRNA HOTAIR promotes proliferation and inhibits apoptosis by sponging miR-214-3p in HPV16 positive cervical cancer cells

Background

Cervical cancer (CC) is one of the most common gynaecological malignancies all around the world. The mechanisms of cervical carcinoma formation remain under close scrutiny. The long non-coding RNAs (lncRNA) and microRNAs (miRNAs) play important roles in controlling gene expression and promoting the development and progression of cervical cancer by acting as competitive endogenous RNA (ceRNA). However, the roles of lncRNA associated with ceRNAs in cervical carcinogenesis remains unknown. In this study, the expression of long non-coding RNA HOTAIR was investigated in HPV16 positive cervical cancer cells, the candidate miRNAs and target genes were identified to clarify putative ceRNAs of HOTAIR/miRNA in cervical cancer cells.

Methods

The proliferation ability of cells was measured by CCK8 and EdU incorporation assays and cell apoptosis was analyzed by flow cytometry. The expression of HOTAIR, miR-214-3p, HPV16 E7 mRNA were detected by qRT-PCR. As for searching for the interaction between miR-214-3p and HOTAIR, the binding sites for miR-214-3p on HOTAIR was predicted by starbase v2.0 database, then dual-luciferase assay was used to verify the binding sites. In addition, Gene Ontology (GO) and protein–protein interaction (PPI) network analysis of target genes of miR-214-3p were performed with bioinformatics analysis. The potential signal pathway regulated by HOTAIR/miR-214-3p was predicted by KEGG enrichment analysis and confirmed by qPCR and WB analysis in cervical cancer cells.

Results

Our results showed that expression of HOTAIR was up-regulated, while that of miR-214-3p was down-regulated in HPV16-positive cervical cancer cells. The expression status of HPV16 E7 played an important role in regulating expression of HOTAIR or miR-214-3p in cervical cancer cells. HOTAIR knockdown could significantly inhibited cell proliferate ability and promote cellular apoptosis, whereas the inhibition of miR-214-3p expression partially reversed such results. Bioinformatics analysis identified 1451 genes as target genes of miR-214-3p. The Gene ontology (GO) and KEGG Pathway enrichment analysis showed that these target genes were mainly related to regulation of cell communication, protein binding, enzyme binding and transferase activity, and Wnt ligand biogenesis. Pathway enrichment analysis results showed that the predicted target genes were significantly enriched in Wnt/β-catenin signaling pathway. Finally, our results confirmed that miR-214-3p could significantly inhibit β-catenin expression in HPV16 positive cancer cells by qPCR and WB analysis.

Conclusion

HOTAIR could act as a ceRNA through binding to miR-214-3p, promote cell proliferation and inhibit the apoptosis of HPV16 positive cervical cancer. HOTAIR/miR-214-3p/Wnt/β-catenin signal pathway might played important regulated roles in HPV16 positive cervical cancer. Our results provided new insight into defining novel biomarkers for cervical cancer.

Impaired Priming of SARS-CoV-2-Specific Naive CD8+ T Cells in Older Subjects

Advanced age is associated with severe symptoms and death upon SARS-CoV-2 infection. Virus-specific CD8⁺ T-cell responses have shown to be protective toward critical COVID-19 manifestations, suggesting that suboptimal cellular immunity may contribute to the age-pattern of the disease. The induction of a CD8⁺ T-cell response against an emerging pathogen like SARS-CoV-2 relies on the activation of naive T cells. To investigate whether the primary CD8⁺ T-cell response against this virus is defective in advanced age, we used an in vitro approach to prime SARS-CoV-2-specific naive CD8⁺ T cells from healthy, unexposed donors of different age groups. Compared to younger adults, older individuals display a poor SARS-CoV-2-specific T-cell priming capacity in terms of both magnitude and quality of the response. In addition, older subjects recognize a lower number of epitopes. Our results implicate that immune aging is associated with altered primary SARS-CoV-2-specific CD8⁺ T-cell responses.

Antibody avidity, persistence, and response to antigen recall: comparison of vaccine adjuvants

Differences in innate immune ‘imprinting’ between vaccine adjuvants may mediate dissimilar effects on the quantity/quality of persisting adaptive responses. We compared antibody avidity maturation, antibody/memory B cell/CD4⁺ T cell response durability, and recall responses to non-adjuvanted fractional-dose antigen administered 1-year post-immunization (Day [D]360), between hepatitis B vaccines containing Adjuvant System (AS)01_B, AS01_E, AS03, AS04, or Alum (NCT00805389). Both the antibody and B cell levels ranked similarly (AS01_B/E/AS03 > AS04 > Alum) at peak response, at D360, and following their increases post-antigen recall (D390). Proportions of high-avidity antibodies increased post-dose 2 across all groups and persisted at D360, but avidity maturation appeared to be more strongly promoted by AS vs. Alum. Post-antigen recall, frequencies of subjects with high-avidity antibodies increased only markedly in the AS groups. Among the AS, total antibody responses were lowest for AS04. However, proportions of high-avidity antibodies were similar between groups, suggesting that MPL in AS04 contributes to avidity maturation. Specific combinations of immunoenhancers in the AS, regardless of their individual nature, increase antibody persistence and avidity maturation.

Current Status of COVID-19 Vaccine Development: Focusing on Antigen Design and Clinical Trials on Later Stages

The global outbreak of coronavirus disease 2019 (COVID-19) is still threatening human health, economy, and social life worldwide. As a counteraction for this devastating disease, a number of vaccines are being developed with unprecedented speed combined with new technologies. As COVID-19 vaccines are being developed in the absence of a licensed human coronavirus vaccine, there remain further questions regarding the long-term efficacy and safety of the vaccines, as well as immunological mechanisms in depth. This review article discusses the current status of COVID-19 vaccine development, mainly focusing on antigen design, clinical trials in later stages, and immunological considerations for further study.

Connecting METTL3 and intratumoural CD33+ MDSCs in predicting clinical outcome in cervical cancer

Background

Methyltransferase-like 3 (METTL3) is a member of the m⁶A methyltransferase family and acts as an oncogene in cancers. Recent studies suggest that host innate immunity is regulated by the enzymes controlling m⁶A epitranscriptomic changes. Here, we aim to explore the associations between the levels of METTL3 and CD33⁺ myeloid-derived suppressor cells (MDSCs) in tumour tissues and the survival of patients with cervical cancer (CC).

Methods

Specimens of paraffin embedded tumour from 197 CC patients were collected. The expression levels of METTL3 and CD33 were measured by immunohistochemical (IHC) staining. The clinical associations of the IHC variants were analysed by Pearson’s or Spearman’s chi-square tests. Overall survival (OS) and disease-free survival (DFS) were estimated by the Kaplan–Meier method and log-rank test. Hazard ratios (HRs) and independent significance were obtained via Cox proportional hazards models for multivariate analyses. METTL3 in CD33⁺ cells or CC-derived cells was knocked down by METTL3-specific siRNA, and MDSC induction in vitro was performed in a co-culture system in the presence of METTL3-siRNA and METTL3-knockdown-CC-derived cells compared with that of the corresponding controls.

Results

We found that tumour tissues displayed increased levels of METTL3 and CD33⁺ MDSCs compared with tumour-adjacent tissues from the same CC patients. Importantly, METTL3 expression was positively related to the density of CD33⁺ cells in tumour tissues (P = 0.011). We further found that the direct CD33⁺CD11b⁺HLA-DR⁻ MDSC induction and tumour-derived MDSC induction in vitro were decreased in the absence of METTL3. The level of METTL3 in tumour microenvironments was significantly related to advanced tumour stage. The levels of METTL3 and CD33⁺ MDSCs in tumour tissues were notably associated with reduced DFS or OS. Cox model analysis revealed that the level of METTL3 in tumour cells was an independent factor for patient survival, specifically for DFS (HR = 3.157, P = 0.022) and OS (HR = 3.271, P = 0.012), while the CD33⁺ MDSC number was an independent predictor for DFS (HR: 3.958, P = 0.031). Interestingly, in patients with advanced-disease stages (II–IV), METTL3 in tumour cells was an independent factor for DFS (HR = 6.725, P = 0.010) and OS (HR = 5.140, P = 0.021), while CD33⁺ MDSC density was an independent factor for OS (HR = 8.802, P = 0.037).

Conclusion

Our findings suggest that CD33⁺ MDSC expansion is linked to high levels of METTL3 and that METTL3 and CD33⁺ MDSCs are independent prognostic factors in CC.

Vaccination and Vaccine Effectiveness: A Commentary of Special Issue Editors

The Special Issue “Vaccination and Vaccine Effectiveness”, published in the journal Vaccines, has the main aim to increase international literature data on vaccine effectiveness and safety and on vaccination strategies in order to reduce vaccine hesitancy and improve vaccination coverage rates. The main topics included in the call for papers were vaccines administered to infants, adolescents, adults, elderly people, at-risk populations (due to comorbidities and personal risk factors) and healthcare workers and strategies adopted to promote vaccination adherence among these categories. This Special Issue started from the assumption that, despite vaccination being universally recognized as one of the best strategies to increase duration and quality of life during the last centuries, vaccination coverage rates are often under the levels recommended to reduce circulation and to extinguish vaccine-preventable diseases. Vaccine hesitancy involves at least 15% of the general population, and healthcare workers also sometimes demonstrate doubts on vaccination effectiveness and safety. At the end of the six-month submission period, 16 articles (15 research article and one review) were accepted after the peer-review processes and published online.

Immunology of HPV-mediated cervical cancer: current understanding

Human papilloma virus (HPV) has emerged as a primary cause of cervical cancer worldwide. HPV is a relatively small (55 nm in diameter) and non-enveloped virus containing approximately 8 kb long double stranded circular DNA genome. To date, 228 genotypes of HPV have been identified. Although all HPV infections do not lead to the development of malignancy of cervix, only persistent infection of high-risk types of HPV (mainly with HPV16 and HPV18) results in the disease. In addition, the immunity of the patients also acts as a key determinant in the carcinogenesis. Since, no HPV type specific medication is available for the patient suffering with cervical cancer, hence, a deep understanding of the disease etiology may be vital for developing an effective strategy for its prevention and management. From the immunological perspectives, the entire mechanisms of disease progression still remain unclear despite continuous efforts. In the present review, the recent developments in immunology of HPV-mediated cervix carcinoma were discussed. At the end, the prevention of disease using HPV type specific recombinant vaccines was also highlighted.

The Tat Protein of HIV-1 Prevents the Loss of HSV-Specific Memory Adaptive Responses and Favors the Control of Viral Reactivation

The development of therapeutic strategies to control the reactivation of the Herpes Simplex Virus (HSV) is an unaddressed priority. In this study, we evaluated whether Tat, a HIV-1 protein displaying adjuvant functions, could improve previously established HSV-specific memory responses and prevent viral reactivation. To this aim, mice were infected with non-lethal doses of HSV-1 and, 44 days later, injected or not with Tat. Mice were then monitored to check their health status and measure memory HSV-specific cellular and humoral responses. The appearance of symptoms associated with HSV-reactivation was observed at significantly higher frequencies in the control group than in the Tat-treated mice. In addition, the control animals experienced a time-dependent decrease in HSV-specific Immunoglobulin G (IgG), while the Tat-treated mice maintained antibody titers over time. IgG levels were directly correlated with the number of HSV-specific CD8⁺ T cells, suggesting an effect of Tat on both arms of the adaptive immunity. Consistent with the maintenance of HSV-specific immune memory, Tat-treated mice showed a better control of HSV-1 re-infection. Although further studies are necessary to assess whether similar effects are observed in other models, these results indicate that Tat exerts a therapeutic effect against latent HSV-1 infection and re-infection by favoring the maintenance of adaptive immunity.