Development of multivalent mRNA vaccine candidates for seasonal or pandemic influenza

An mRNA vaccine candidate encoding cholera toxin subunit B and conserved antigens of influenza viruses confers cross-protection against influenza a viruses in adult and aged mice

Currently, vaccination with influenza vaccines is still an effective strategy to prevent infection by seasonal influenza virus. However, seasonal influenza vaccines frequently fail to induce effective immune protection against rapidly changing seasonal influenza viruses and emerging zoonotic influenza viruses. In addition, seasonal influenza vaccines may not confer potent protection in elderly and immunocompromised individuals. There is an urgent need to develop potent broad-spectrum influenza vaccines to address this problem. Herein, we designed an mRNA-based broad-spectrum influenza vaccine candidate encoding cholera toxin subunit B and conserved antigens of influenza viruses. In both adult and aged mice, this universal influenza mRNA vaccine candidate stimulated robust T-cell and humoral immune responses and conferred effective protection against broad-spectrum influenza viruses in both adult and aged mice.

Development and efficacy of a novel mRNA cocktail for the delivery of African swine fever virus antigens and induction of immune responses

African swine fever (ASF) is a highly lethal infectious disease affecting pigs. Although several vaccine formulations have been developed to protect from ASF virus (ASFV) infection, none have yet provided complete protection without side effects or the risk of progressing to chronic infection. mRNA vaccines offer unparalleled advantages in terms of safety and ability to induce immune responses. In this study, we designed six mRNA vaccines encoding key antigenic proteins of ASFV- B602L, CD2V, EP153R, P30, P54, and P72 and combined them into an mRNA cocktail for vaccination in mice and pigs. Our findings suggest that the mRNA cocktail is capable of provoking robust multivalent humoral and cellular immune responses while maintaining a favorable safety profile. Thus, it may serve as a potential approach for controlling ASF transmission, contributing to the ongoing efforts to develop effective and safe ASFV vaccines. The administration of the mRNA cocktail induced both humoral and cellular immune responses in mice and pigs, suggesting a potential for future ASFV vaccine development.IMPORTANCEThis study explores an mRNA vaccine encoding six critical African swine fever virus (ASFV) antigens (B602L, CD2V, EP153R, P30, P54, P72), demonstrating its ability to induce robust humoral and cellular immune responses in both mice and pigs. This innovative approach serves as a significant advancement in ASFV vaccine development by addressing safety and efficacy concerns. The findings suggest that the mRNA cocktail developed in this study represents a step forward in ASFV vaccine research and development. This strategy holds promise for contributing to ASFV control by offering possibly safer and more effective alternatives to conventional vaccines. This could significantly impact ASF management and prevention strategies globally, ultimately benefiting animal health and reducing economic losses.

Synthetic and Biogenic Materials for Oral Delivery of Biologics: From Bench to Bedside

The development of nucleic acid and protein drugs for oral delivery has lagged behind their production for conventional nonoral routes. Over the past decade, the evolution of DNA- and RNA-based technologies combined with the innovation of state-of-the-art delivery vehicles for nucleic acids has brought rapid advancements to the biopharmaceutical field. Nucleic acid therapies have the potential to achieve long-lasting effects, or even cures, by inhibiting or editing genes, which is not possible with conventional small-molecule drugs. However, challenges and limitations must be addressed before these therapies can provide cures for chronic conditions and rare diseases, rather than only offering temporary relief. Nucleic acids and proteins face premature degradation in the acidic, enzyme-rich stomach environment and are rapidly cleared by the liver. To overcome these challenges, various delivery vehicles have been developed to transport therapeutic compounds to the intestines, where the active compounds are released and gut microbiota and mucosal immune system also play an important role. This review provides a comprehensive overview of the promises and pitfalls associated with the oral route of administration of biologics, current delivery systems, applications of orally delivered therapeutics, and the challenges and considerations for translation of nucleic acid and protein therapeutics into clinical practice.

Induction of enhanced stem-directed neutralizing antibodies by HA2-16 ferritin nanoparticles with H3 influenza virus boost

Current seasonal influenza vaccines offer limited protection against influenza viruses due to genetic drift. The urgent need for a universal influenza vaccine to combat highly mutated strains is evident. This study utilized the conserved HA2 subunit of hemagglutinin (HA) and a short linear epitope of HA2 (HA2-16) from the H3 influenza virus to conjugate with ferritin, resulting in the construction of recombinant immunogens termed HA2-F and HA2-16-F, respectively. In vitro characterization confirmed the self-assembly of prokaryotically expressed HA2-F and HA2-16-F into nanoparticles (NPs). To simulate natural virus infection in the vaccinated population, intranasal infection with the whole H3N2 virus was administered as a final boost. Enhanced binding activity to A/Hong Kong/4801/2014 (H3N2) and A/17/California/2009/38 (H1N1) virus was detected in the HA2-16 group induced by the A/Wisconsin/67/2005 (H3N2) virus boost (Titer >104). Furthermore, higher titers of neutralizing antibodies were elicited by HA2-16-F NP (ID50: 50.4-631.0) compared to those by HA2-F NP (ID50: 20.3-178.2). These results demonstrated that the H3N2 virus boost focused the antibody response on the HA2-16 epitope. Additionally, our immunization strategy was found to reduce serum ferritin reactive antibodies. In summary, HA2-16 not only holds promise as a vaccine candidate but also exhibits significant potential for influenza vaccine production, particularly in enhancing the levels of induced stem-directed antibodies. This study contributes to the development of recombinant immunogens for improved influenza vaccine efficacy.

Impact of Extended Dosing Intervals and Ipsilateral Versus Contralateral Boosting on mRNA Vaccine Immunogenicity in Mice

BACKGROUND

Although mRNA vaccines have the potential to be developed and deployed rapidly to combat infectious diseases, the ideal method of administration and boosting schedule strategy for generating optimal immunogenicity is an area of active research. We compared the immune responses resulting from different schedules for prime-boost and boosting either ipsilaterally or contralaterally in relation to the initial vaccine dose.

METHODS

Influenza hemagglutinin (HA) was used as a model antigen for different vaccination regimens in mice using both mRNA lipid nanoparticles (mRNA-LNP) and AF03-adjuvanted recombinant protein (rHA-AF03) vaccines.

RESULTS

Increasing the prime-boost interval resulted in higher levels of serum anti-HA IgG and functional antibody hemagglutination inhibition (HAI) responses in mRNA-LNP-vaccinated animals, which correlated with an induction of germinal center (GC) B cells and follicular helper T (Tfh) cells in lymph nodes. In addition, longer prime-boost intervals resulted in higher levels of IL-2 and TNF-α producing CD4+ T cells two weeks after boosting. The number of Ig-secreting long-lived plasma cells increased with the length of prime-boost intervals. Contralateral boosting resulted in an increase in HAI titers and GC B cells compared to an ipsilateral boost. However, significantly higher numbers of GC B cells were induced in the draining lymph nodes following ipsilateral boosting than in the non-draining lymph nodes.

CONCLUSIONS

Overall, our data provides insights into the immune mechanisms of action of mRNA-LNP to develop the optimal vaccine regimen for mRNA vaccine platforms.

Targeting Bottlenecks in Malaria Transmission: Antibody-Epitope Descriptions Guide the Design of Next-Generation Biomedical Interventions

Malaria continues to pose a significant burden to global health. Thus, a strong need exists for the development of a diverse panel of intervention strategies and modalities to combat malaria and achieve elimination and eradication goals. Deploying interventions that target bottlenecks in the transmission life cycle of the causative agent of malaria, Plasmodium parasites, is an attractive strategy. The development of highly potent antibody-based biologics, including vaccines, can be greatly facilitated by an in-depth molecular understanding of antibody-epitope interactions. Here, we provide an overview of structurally characterized antibodies targeting lead vaccine candidates expressed during the bottlenecks of the Plasmodium life cycle which include the pre-erythrocytic and sexual stages. The repeat region of the circumsporozoite protein (CSP), domain 1 of Pfs230 and domains 1 and 3 of Pfs48/45 are critical Plasmodium regions targeted by the most potent antibodies at the two bottlenecks of transmission, with other promising targets emerging and requiring further characterization.

Decoding Codon Usage Patterns in High-Risk Human Papillomavirus Genomes: A Comprehensive Analysis

Human Papillomavirus (HPV) is a major contributor to various human cancers, particularly cervical cancer. Despite its significant impact, the codon usage bias in high-risk HPV types has not been extensively studied. Understanding this bias, however, could provide valuable insights into the virus itself and inform the optimization of vaccine design. This study explores codon usage bias within the genomes of 17 high-risk HPV types (HPV-16, 18, 26, 31, 33, 35, 39, 45, 51, 52, 53, 56, 58, 59, 66, 68, and 82) through comparative analysis. While overall codon usage preference across these genotypes is not highly significant, a notable trend emerges in the preference for codons ending in A or U, with 24 out of 26 favored codons (Relative Synonymous Codon Usage > 1) ending in A or U. Moreover, no common optimal codons are shared among the 17 genomes. The study also identifies the underrepresentation of CpG and ApA dinucleotides, alongside the overrepresentation of CpA and UpG, which likely contribute to codon usage preferences that may influence viral replication and immune evasion strategies. Integrated analysis further suggests that natural selection is the primary force driving codon usage bias in these high-risk HPV genomes. Additionally, these HPVs exhibit a limited set of favored codons shared with humans, potentially minimizing competition for translation resources. This study offers new insights into codon usage bias in high-risk HPVs and underscores the importance of this understanding for optimizing vaccine design.

Novel mRNA vaccines induce potent immunogenicity and afford protection against tuberculosis

Introduction

Mycobacterium tuberculosis (Mtb) is the causative agent of tuberculosis (TB), a disease with a severe global burden. The intractability of Mtb has prevented the identification of clear correlates of protection against TB and hindered the development of novel TB vaccines that are urgently required. Lipid nanoparticle (LNP)-formulated mRNA is a highly promising vaccine platform that has yet to be thoroughly applied to TB.

Methods

We selected five Mtb antigens (PPE15, ESAT6, EspC, EsxI, MetE) and evaluated their potential as LNP-formulated mRNA vaccines, both when each antigen was delivered individually, and when all five antigens were combined in a mix regimen (m-Mix).

Results

Each mRNA construct demonstrated unique cellular and humoral immunogenicity, and both m-Mix, as well as the single antigen EsxI, conferred significant protection in a murine Mtb challenge model. Whilst the potent immune responses of each mRNA were maintained when applied as a boost to BCG, there was no additional increase to the efficacy of BCG. Combination of m-Mix with a recombinant, replication-deficient chimpanzee adenovirus (ChAdOx1), in a heterologous prime-boost delivery (C-m-Mix), appeared to result in increased protection upon murine Mtb infection, than either regimen alone.

Discussion

This work warrants further investigation of LNP-formulated mRNA vaccines for TB, whilst indicating the potential of m-Mix and C-m-Mix to progress to further stages of vaccine development.

Advances in nucleic acid-based cancer vaccines

Nucleic acid vaccines have emerged as crucial advancements in vaccine technology, particularly highlighted by the global response to the COVID-19 pandemic. The widespread administration of mRNA vaccines against COVID-19 to billions globally marks a significant milestone. Furthermore, the approval of an mRNA vaccine for Respiratory Syncytial Virus (RSV) this year underscores the versatility of this technology. In oncology, the combination of mRNA vaccine encoding neoantigens and immune checkpoint inhibitors (ICIs) has shown remarkable efficacy in eliciting protective responses against diseases like melanoma and pancreatic cancer. Although the use of a COVID-19 DNA vaccine has been limited to India, the inherent stability at room temperature and cost-effectiveness of DNA vaccines present a viable option that could benefit developing countries. These advantages may help DNA vaccines address some of the challenges associated with mRNA vaccines. Currently, several trials are exploring the use of DNA-encoded neoantigens in combination with ICIs across various cancer types. These studies highlight the promising role of nucleic acid-based vaccines as the next generation of immunotherapeutic agents in cancer treatment. This review will delve into the recent advancements and current developmental status of both mRNA and DNA-based cancer vaccines.

Expert consensus on the benefits of neuraminidase in conventional influenza vaccines: a Delphi study

BACKGROUND

Seasonal vaccination is the mainstay of human influenza prevention. Licensed influenza vaccines are regularly updated to account for viral mutations and antigenic drift and are standardised for their haemagglutinin content. However, vaccine effectiveness remains suboptimal. Neuraminidase (NA) evolves more gradually than hemagglutinin and has been demonstrated to provide added clinical benefits. However, NA is not currently a mandated or standardised component of influenza vaccines.

METHODS

Here, we collated expert opinions on the importance of NA in influenza vaccines in a two-stage Delphi survey. Nine statements about NA were formulated by a steering committee based on a targeted literature review. In the survey's first round, panellists recruited from three continents were requested to report on their agreement with each statement and estimate the strength of evidence for each statement. Panellists were also requested to explain their choice of answer and suggest revisions to the statements. Consensus was considered reached if ≥ 75% of panellists agreed with a statement. If consensus was not reached for a statement, this statement was revised and included in the survey's second round.

RESULTS

Nine panellists with a broad range of NA-related expertise, including clinical, research, and public health experience, completed the survey. They agreed that anti-NA responses acquired via natural infection or vaccination are associated with protective immunity independently of haemagglutinin and that NA provided additional advantages including improving disease severity metrics. The experts identified several knowledge gaps concerning heterologous cross-reactivity of vaccine-induced anti-NA antibodies, correlations between anti-NA titres and reduced transmission or infection risks, and differences in anti-NA responses to seasonal influenza vaccines.

CONCLUSIONS

NA is an important influenza vaccine component and is associated with specific benefits. These benefits would likely be greater if NA content were standardised. Additional research is needed to optimise vaccines for anti-NA effects.

Conjugation of Multiple Proteins Onto the Surface of PLGA/Lipid Hybrid Nanoparticles

Nanoparticles are increasingly being used in the development of vaccines for disease prevention or treatment. Recent research has demonstrated that conjugating a protein onto the surface of nanoparticles can significantly increase its immunogenicity. Considering various pathogens that threaten human health, multivalent vaccines are often desirable. Up to now, nanoparticle-based vaccines are mostly limited to one protein per nanoparticle. No research has been conducted to explore the possibility of conjugating more than one protein onto the surface of a nanoparticle. Here we developed a specific conjugation strategy to conjugate multiple proteins to the PLGA/lipid hybrid nanoparticle surface. The maleimide-thiol Michael addition, Aizde-DBCO (Dibenzocyclooctyne), and TCO (trans-cycloctene)-Tetrazine click chemistry were employed to conjugate three different proteins, subunit keyhole limpet hemocyanin (sKLH), Ovalbumin (OVA), and cross-reactive material 197 (CRM197), to the surface of PLGA/lipid hybrid nanoparticles (hNPs). The successful results of this study pave the way for developing multivalent vaccines against different pathogens.

Immunoprotective effect of chitosan nanoparticles with different particle sizes against H9N2 avian influenza infection

H9N2 is the most common avian influenza virus (AIV), which causes significant losses in chickens. Safe and effective vaccines are crucial for the prevention of H9N2 AIVs. Chitosan nanoparticles, as novel adjuvants, enhance vaccine immunity and biocompatibility; however, the impact of particle size on the immunological effects remains underexplored. To solve these problems and to prepare an efficient novel H9N2 vaccine, we constructed four N-2-HACC/CMCS NPs (NHC NPs) of different particle sizes (165.6 ± 12.0 nm, 272.5 ± 7.0 nm, 343.2 ± 8.0 nm, and 443.5 ± 15.0 nm). Subsequent in vivo immunogenicity screening revealed that H9N2 with the 272.5 ± 7.0 nm NHC NPs vaccine group induced higher levels of neutralizing antibodies in the early stage of the immune response, while the 343.2 ± 8.0 nm NHC NPs vaccine group induced higher levels of neutralizing antibodies in the late stages of the immune response. Subsequently, the results of the optimal particle size combination screening revealed that more neutralizing antibodies were induced when the NHC NPs particle size combination of 272.5 ± 7.0 nm:343.2 ± 8.0 nm ratio was 1.5:1. This optimal particle size combination for NP vaccines promoted lymphocyte proliferation, induced higher IgG2a/IgG1 ratios, and promoted the production of cytokines (i.e., IL-2, IL-4, and IFN-γ). Moreover, a mechanistic analysis revealed that the optimal NHC NPs combination triggered the activation of antigen presenting cells via TLR4 and participated in immune responses through the production of NO and TNF-α. Taken together, our study revealed that the optimal combination of NHC NPs may be a promising strategy against influenza viruses.

An influenza mRNA vaccine protects ferrets from lethal infection with highly pathogenic avian influenza A(H5N1) virus

The global spread of the highly pathogenic avian influenza (HPAI) A(H5N1) virus poses a serious pandemic threat, necessitating the swift development of effective vaccines. The success of messenger RNA (mRNA) vaccine technology in the COVID-19 pandemic, marked by its rapid development and scalability, demonstrates its potential for addressing other infectious threats, such as HPAI A(H5N1). We therefore evaluated mRNA vaccine candidates targeting panzootic influenza A(H5) clade 2.3.4.4b viruses, which have been shown to infect a range of mammalian species, including most recently being detected in dairy cattle. Ferrets were immunized with mRNA vaccines encoding either hemagglutinin alone or hemagglutinin and neuraminidase, derived from a 2.3.4.4b prototype vaccine virus recommended by the World Health Organization. Kinetics of the immune responses, as well as protection against a lethal challenge dose of A(H5N1) virus, were assessed. Two doses of mRNA vaccination elicited robust neutralizing antibody titers against a 2022 avian isolate and a 2024 human isolate. Further, mRNA vaccination conferred protection from lethal challenge, whereas all unvaccinated ferrets succumbed to infection. It also reduced viral titers in the upper and lower respiratory tracts of infected ferrets. These results underscore the effectiveness of mRNA vaccines against HPAI A(H5N1), showcasing their potential as a vaccine platform for future influenza pandemics.

Advantages of Broad-Spectrum Influenza mRNA Vaccines and Their Impact on Pulmonary Influenza

Influenza poses a significant global health challenge due to its rapid mutation and antigenic variability, which often leads to seasonal epidemics and frequent outbreaks. Traditional vaccines struggle to offer comprehensive protection because of mismatches with circulating viral strains. The development of a broad-spectrum vaccine is therefore crucial. This paper explores the potential of mRNA vaccine technology to address these challenges by providing a swift, adaptable, and broad protective response against evolving influenza strains. We detail the mechanisms of antigenic variation in influenza viruses and discuss the rapid design and production, enhanced immunogenicity, encoding of multiple antigens, and safety and stability of mRNA vaccines compared to traditional methods. By leveraging these advantages, mRNA vaccines represent a revolutionary approach in influenza prevention, potentially offering broad-spectrum protection and significantly improving global influenza management and response strategies.

Herpes zoster mRNA vaccine induces superior vaccine immunity over licensed vaccine in mice and rhesus macaques

Herpes zoster remains an important global health issue and mainly occurs in aged and immunocompromised individuals with an early exposure history to Varicella Zoster Virus (VZV). Although the licensed vaccine Shingrix has remarkably high efficacy, undesired reactogenicity and increasing global demand causing vaccine shortage urged the development of improved or novel VZV vaccines. In this study, we developed a novel VZV mRNA vaccine candidate (named as ZOSAL) containing sequence-optimized mRNAs encoding full-length glycoprotein E encapsulated in an ionizable lipid nanoparticle. In mice and rhesus macaques, ZOSAL demonstrated superior immunogenicity and safety in multiple aspects over Shingrix, especially in the induction of strong T-cell immunity. Transcriptomic analysis revealed that both ZOSAL and Shingrix could robustly activate innate immune compartments, especially Type-I IFN signalling and antigen processing/presentation. Multivariate correlation analysis further identified several early factors of innate compartments that can predict the magnitude of T-cell responses, which further increased our understanding of the mode of action of two different VZV vaccine modalities. Collectively, our data demonstrated the superiority of VZV mRNA vaccine over licensed subunit vaccine. The mRNA platform therefore holds prospects for further investigations in next-generation VZV vaccine development.

Design and development of mRNA and self-amplifying mRNA vaccine nanoformulations

The rapid evolution of mRNA vaccines, highlighted by Pfizer-BioNTech and Moderna's COVID-19 vaccines, has transformed vaccine development and therapeutic approaches. Self-amplifying mRNA (saRNA) vaccines, a groundbreaking advancement in RNA-based vaccines, offer promising possibilities for disease prevention and treatment, including potential applications in cancer and neurodegenerative diseases. This review explores the complex design and development of these innovative vaccines, with a focus on their nanoscale formulations that utilize nanotechnology to improve their delivery and effectiveness. It articulates the fundamental principles of mRNA and saRNA vaccines, their mechanisms of action, and the role of synthetic mRNA in eliciting immune responses. The review further elaborates on various nanoscale delivery systems (e.g., lipid nanoparticles, polymeric nanoparticles and other nanocarriers), emphasizing their advantages in enhancing mRNA stability and cellular uptake. It addresses advanced nanoscale delivery techniques such as microfluidics and discusses the challenges in formulating mRNA and saRNA vaccines. By incorporating the latest technologies and current research, this review provides a thorough overview of recent mRNA and saRNA nanovaccines advancements, highlighting their potential to revolutionize vaccine technology and broaden clinical applications.

Prophylactic and therapeutic vaccine development: advancements and challenges

Biomedical research is fundamental in developing preventive and therapeutic vaccines, serving as a cornerstone of global public health. This review explores the key concepts, methodologies, tools, and challenges in the vaccine development landscape, focusing on transitioning from basic biomedical sciences to clinical applications. Foundational disciplines such as virology, immunology, and molecular biology lay the groundwork for vaccine creation, while recent innovations like messenger RNA (mRNA) technology and reverse vaccinology have transformed the field. Additionally, it highlights the role of pharmaceutical advancements in translating lab discoveries into clinical solutions. Techniques like CRISPR-Cas9, genome sequencing, monoclonal antibodies, and computational modeling have significantly enhanced vaccine precision and efficacy, expediting the development of vaccines against infectious diseases. The review also discusses challenges that continue to hinder progress, including stringent regulatory pathways, vaccine hesitancy, and the rapid emergence of new pathogens. These obstacles underscore the need for interdisciplinary collaboration and the adoption of innovative strategies. Integrating personalized medicine, nanotechnology, and artificial intelligence is expected to revolutionize vaccine science further. By embracing these advancements, biomedical research has the potential to overcome existing challenges and usher in a new era of therapeutic and prophylactic vaccines, ultimately improving global health outcomes. This review emphasizes the critical role of vaccines in combating current and future health threats, advocating for continued investment in biomedical science and technology.

Immunogenicity and Efficacy of Combined mRNA Vaccine Against Influenza and SARS-CoV-2 in Mice Animal Models

Background. The combined or multivalent vaccines are actively used in pediatric practice and offer a series of advantages, including a reduced number of injections and visits to the doctor, simplicity of the vaccination schedule and minimization of side effects, easier vaccine monitoring and storage, and lower vaccination costs. The practice of widespread use of the combined vaccines has shown the potential to increase vaccination coverage against single infections. The mRNA platform has been shown to be effective against the COVID-19 pandemic and enables the development of combined vaccines. There are currently no mRNA-based combined vaccines approved for use in humans. Some studies have shown that different mRNA components in a vaccine can interact to increase or decrease the immunogenicity and efficacy of the combined vaccine. Objectives. In the present study, we investigated the possibility of combining the mRNA vaccines, encoding seasonal influenza and SARS-CoV-2 antigens. In our previous works, both vaccine candidates have shown excellent immunogenicity and efficacy profiles in mice. Methods. The mRNA-LNPs were prepared by microfluidic mixing, immunogenicity in mice was assessed by hemagglutination inhibition assay, enzyme-linked immunoassay and virus neutralization assay. Immunological efficacy was assessed in a mouse viral challenge model. Results. In this work, we demonstrated that the individual mRNA components of the combined vaccine did not affect the immunogenicity level of each other. The combined vaccine demonstrated excellent protective efficacy, providing a 100% survival rate when mice were infected with the H1N1 influenza virus and reducing the viral load in the lungs. Four days after the challenge with SARS-CoV-2 EG.5.1.1., no viable virus and low levels of detectable viral RNA were observed in the lungs of vaccinated mice. Conclusions. The combination does not lead to mutual interference between the individual vaccines. We believe that such a combined mRNA-based vaccine could be a good alternative to separated human vaccinations for the prevention of COVID-19 and influenza.

Comparison of capillary electrophoresis-based methods for the analytical characterization of purity and stability of in vitro transcribed mRNA

Messenger RNA (mRNA) is rapidly growing as a therapeutic modality for vaccination and the treatment of a wide range of diseases. As a result, there is an increased demand for mRNA-based analytical methods capable of assessing purity and stability, which are considered critical quality attributes (CQAs). In recent decades capillary electrophoresis (CE) has emerged alongside liquid chromatography (LC) as an important tool for the assessment of purity and stability of mRNA therapeutics. CE offers a variety of advantages over conventional LC or gel-based analytical methods, including reduced injection volume, increased resolution, and increased separation efficiency. In this study we compared CE-based analytical methods: the Agilent RNA 6000 Nano Kit, the Revvity RNA Reagent Kit, the Sciex RNA 9000 Purity and Integrity Kit, and the Agilent HS RNA Kit. These methods were evaluated on their vendor-recommended instruments: the Bioanalyzer, LabChip GXII, PA800 Plus, and Fragment Analyzer, respectively. We assessed the ability of these methods to measure mRNA integrity, purity, and stability. Furthermore, several parameters for each method were also assessed: selectivity, precision, resolution, analysis time, and ease of use. Based on our results, all four methods are suitable for use in the characterization of in vitro transcribed (IVT) mRNA, depending on the intended application. The Sciex RNA 9000 Purity and Integrity kit method achieved the highest selectivity and resolving power compared with the other methods, making it the most suitable for high-resolution, in-depth sample characterization. In comparison, the Agilent RNA 6000 Nano Kit, Revvity RNA Reagent Kit, and Agilent HS RNA Kit achieved lower selectivity and resolution, but their faster analysis times make them more suitable for high-throughput and screening applications.

Preclinical immunogenicity and safety of hemagglutinin-encoding modRNA influenza vaccines

Seasonal epidemics of influenza viruses are responsible for a significant global public health burden. Vaccination remains the most effective way to prevent infection; however, due to the persistence of antigenic drift, vaccines must be updated annually. The selection of vaccine strains occurs months in advance of the influenza season to allow adequate time for production in eggs. RNA vaccines offer the potential to accelerate production and improve efficacy of influenza vaccines. We leveraged the nucleoside-modified RNA (modRNA) platform technology and lipid nanoparticle formulation process of the COVID-19 mRNA vaccine (BNT162b2; Comirnaty®) to create modRNA vaccines encoding hemagglutinin (HA) (modRNA-HA) for seasonal human influenza strains and evaluated their preclinical immunogenicity and toxicity. In mice, a monovalent modRNA vaccine encoding an H1 HA demonstrated robust antibody responses, HA-specific Th1-type CD4+ T cell responses, and HA-specific CD8+ T cell responses. In rhesus and cynomolgus macaques, the vaccine exhibited durable functional antibody responses and HA-specific IFN-γ+ CD4+ T cell responses. Immunization of mice with monovalent, trivalent, and quadrivalent modRNA-HA vaccines generated functional antibody responses targeting the seasonal influenza virus(es) encoded in the vaccines that were greater than, or similar to, those of a licensed quadrivalent influenza vaccine. Monovalent and quadrivalent modRNA-HA vaccines were well-tolerated by Wistar Han rats, with no evidence of systemic toxicity. These nonclinical immunogenicity and safety data support further evaluation of the modRNA-HA vaccines in clinical studies.

Bivalent norovirus mRNA vaccine elicits cellular and humoral responses protecting human enteroids from GII.4 infection

Nucleoside-modified mRNA-LNP vaccines have revolutionized vaccine development against infectious pathogens due to their ability to elicit potent humoral and cellular immune responses. In this article, we present the results of the first norovirus vaccine candidate employing mRNA-LNP platform technology. The mRNA-LNP bivalent vaccine encoding the major capsid protein VP1 from GI.1 and GII.4 of human norovirus, generated high levels of neutralizing antibodies, robust cellular responses, and effectively protected human enteroids from infection by the most prevalent genotype (GII.4). These results serve as a proof of concept, demonstrating that a modified-nucleoside mRNA-LNP vaccine based on norovirus VP1 sequences can stimulate an immunogenic response in vivo and generates neutralizing antibodies capable of preventing viral infection in models of human gastrointestinal tract infection.

CircRNA based multivalent neuraminidase vaccine induces broad protection against influenza viruses in mice

Developing broad-spectrum influenza vaccines is crucial for influenza control and potential pandemic preparedness. Here, we reported a novel vaccine design utilizing circular RNA (circRNA) as a delivery platform for multi-subtype neuraminidases (NA) (influenza A N1, N2, and influenza B Victoria lineage NA) immunogens. Individual NA circRNA lipid nanoparticles (LNP) elicited robust NA-specific antibody responses with neuraminidase inhibition activity (NAI), preventing the virus from egressing and infecting neighboring cells. Additionally, the administration of circRNA LNP induced cellular immunity in mice. To achieve a universal influenza vaccine, we combined all three subtypes of NA circRNA-LNPs to generate a trivalent circRNA vaccine. The trivalent vaccine elicited a balanced antibody response against all three NA subtypes and a Th1-biased immune response in mice. Moreover, it protected mice against the lethal challenge of matched and mismatched H1N1, H3N2, and influenza B viruses, encompassing circulating and ancestral influenza virus strains. This study highlights the potential of delivering multiple NA antigens through circRNA-LNPs as a promising strategy for effectively developing a universal influenza vaccine against diverse influenza viruses.

A combination influenza mRNA vaccine candidate provided broad protection against diverse influenza virus challenge

Influenza viruses present a significant threat to global health. The production of a universal vaccine is considered essential due to the ineffectiveness of current seasonal influenza vaccines against mutant strains. mRNA technology offers new prospects in vaccinology, with various candidates for different infectious diseases currently in development and testing phases. In this study, we encapsulated a universal influenza mRNA vaccine. The vaccine encoded influenza hemagglutinin (HA), nucleoprotein (NP), and three tandem repeats of matrix protein 2 (3M2e). Twice-vaccinated mice exhibited strong humoral and cell-mediated immune responses in vivo. Notably, these immune responses led to a significant reduction in viral load of the lungs in challenged mice, and also conferred protection against future wild-type H1N1, H3N2, or H5N1 influenza virus challenges. Our findings suggest that this mRNA-universal vaccine strategy for influenza virus may be instrumental in mitigating the impact of future influenza pandemics.

Recombinant Hemagglutinin Protein from H9N2 Avian Influenza Virus Exerts Good Immune Effects in Mice

The H9N2 subtype of avian influenza virus (AIV) causes enormous economic losses and poses a significant threat to public health; the development of vaccines against avian influenza is ongoing. To study the immunogenicity of hemagglutinin (HA) protein, we constructed a recombinant pET-32a-HA plasmid, induced HA protein expression with isopropyl β-D-1-thiogalactopyranoside (IPTG), verified it by SDS-PAGE and Western blotting, and determined the sensitivity of the recombinant protein to acid and heat. Subsequently, mice were immunized with the purified HA protein, and the immunization effect was evaluated according to the hemagglutination inhibition (HI) titer, serum IgG antibody titer, and cytokine secretion level of the mice. The results showed that the molecular weight of the HA protein was approximately 84 kDa, and the protein existed in both soluble and insoluble forms; in addition, the HA protein exhibited good acid and thermal stability, the HI antibody titer reached 6 log2-8 log2, and the IgG-binding antibody titer was 1:1,000,000. Moreover, the levels of IL-2, IL-4, and IL-5 in the immunized mouse spleen cells were significantly increased compared with those in the control group. However, the levels of IL-1β, IL-6, IL-13, IFN-γ, IL-18, TNF-α, and GM-CSF were decreased in the immunized group. The recombinant HA protein utilized in this study exhibited good stability and exerted beneficial immune effects, providing a theoretical basis for further research on influenza vaccines.

Multivalent mRNA Vaccine Elicits Broad Protection against SARS-CoV-2 Variants of Concern

SARS-CoV-2 new waves are primarily caused by changes to the spike protein (S), which can substantially decrease the efficacy of vaccines. Therefore, we tested several multivalent mRNA-LNP vaccines, targeting the full-length S proteins of different variants, and identified an optimal combination for protection against VOCs in BALB/c mice. The tested formulations included trivalent (WT + BA.5 + XBB.1.5), pentavalent (WT + BA.5 + XBB.1.5 + BQ.1.1 + CH.1.1), and octavalent (WT + BA.5 + XBB.1.5 + BQ.1.1 + CH.1.1 + Alpha + Delta + BA.2) vaccines. Among these multivalent vaccines, the pentavalent vaccine showed superior protection for almost all tested variants. Despite this, each multivalent vaccine elicited greater broad-spectrum neutralizing antibodies than the previously evaluated bivalent vaccine (WT + BA.5). Subsequently, we redesigned the multivalent vaccine to efficiently generate neutralizing antibodies against recent VOCs, including EG.5.1. Immunization with the redesigned pentavalent vaccine (WT + EG.5.1 + XBB.1.16 + Delta + BA.5) showed moderate levels of protection against recent Omicron VOCs. Results suggest that the neutralization activity of multivalent vaccines is better than those of the tested bivalent vaccines against WT + BA.5 and WT + EG.5.1. Moreover, the pentavalent vaccine we developed may be highly useful for neutralizing new Omicron VOCs.

Distinct dynamics of mRNA LNPs in mice and nonhuman primates revealed by in vivo imaging

The characterization of vaccine distribution to relevant tissues after in vivo administration is critical to understanding their mechanisms of action. Vaccines based on mRNA lipid nanoparticles (LNPs) are now being widely considered against infectious diseases and cancer. Here, we used in vivo imaging approaches to compare the trafficking of two LNP formulations encapsulating mRNA following intramuscular administration: DLin-MC3-DMA (MC3) and the recently developed DOG-IM4. The mRNA formulated in DOG-IM4 LNPs persisted at the injection site, whereas mRNA formulated in MC3 LNPs rapidly migrated to the draining lymph nodes. Furthermore, MC3 LNPs induced the fastest increase in blood neutrophil counts after injection and greater inflammation, as shown by IL-1RA, IL-15, CCL-1, and IL-6 concentrations in nonhuman primate sera. These observations highlight the influence of the nature of the LNP on mRNA vaccine distribution and early immune responses.

Vaccine approaches and treatment aspects against Crimean Congo hemorrhagic fever

Crimean-Congo hemorrhagic fever [CCHF] is a severe infectious viral disease caused by a tick borne virus which can lead to fatal hemorrhagic disease in humans. It has been reported from some continents including Africa, Asia and Europe. Virus is transmitted to human mainly through tick bite, whose acquire infection from reservoirs wild and domesticated mammalians and ostriches. Currently no approved vaccine or drug is available for CCHF and prevention is mainly based on biosecurity measures. Ribavirin is the only approved drug that has been used in some countries to treat human disease, however some new studies did not prove the Ribavirin efficacy. Different strategies to design effective vaccines, have been conducted through years, from inactivated virus to nucleotide-based ones including DNA and mRNA vaccines. In this study we review of pioneering vaccine candidate platforms.

Frameworks for transformational breakthroughs in RNA-based medicines

RNA has sparked a revolution in modern medicine, with the potential to transform the way we treat diseases. Recent regulatory approvals, hundreds of new clinical trials, the emergence of CRISPR gene editing, and the effectiveness of mRNA vaccines in dramatic response to the COVID-19 pandemic have converged to create tremendous momentum and expectation. However, challenges with this relatively new class of drugs persist and require specialized knowledge and expertise to overcome. This Review explores shared strategies for developing RNA drug platforms, including layering technologies, addressing common biases and identifying gaps in understanding. It discusses the potential of RNA-based therapeutics to transform medicine, as well as the challenges associated with improving applicability, efficacy and safety profiles. Insights gained from RNA modalities such as antisense oligonucleotides (ASOs) and small interfering RNAs are used to identify important next steps for mRNA and gene editing technologies.

The antigenic landscape of human influenza N2 neuraminidases from 2009 until 2017

Human H3N2 influenza viruses are subject to rapid antigenic evolution which translates into frequent updates of the composition of seasonal influenza vaccines. Despite these updates, the effectiveness of influenza vaccines against H3N2-associated disease is suboptimal. Seasonal influenza vaccines primarily induce hemagglutinin-specific antibody responses. However, antibodies directed against influenza neuraminidase (NA) also contribute to protection. Here, we analysed the antigenic diversity of a panel of N2 NAs derived from human H3N2 viruses that circulated between 2009 and 2017. The antigenic breadth of these NAs was determined based on the NA inhibition (NAI) of a broad panel of ferret and mouse immune sera that were raised by infection and recombinant N2 NA immunisation. This assessment allowed us to distinguish at least four antigenic groups in the N2 NAs derived from human H3N2 viruses that circulated between 2009 and 2017. Computational analysis further revealed that the amino acid residues in N2 NA that have a major impact on susceptibility to NAI by immune sera are in proximity of the catalytic site. Finally, a machine learning method was developed that allowed to accurately predict the impact of mutations that are present in our N2 NA panel on NAI. These findings have important implications for the renewed interest to develop improved influenza vaccines based on the inclusion of a protective NA antigen formulation.

The Platform Technology Approach to mRNA Product Development and Regulation

mRNA-lipid nanoparticle (LNP) medicinal products can be considered a platform technology because the development process is similar for different diseases and conditions, with similar noncoding mRNA sequences and lipid nanoparticles and essentially unchanged manufacturing and analytical methods often utilised for different products. It is critical not to lose the momentum built using the platform approach during the development, regulatory approval and rollout of vaccines for SARS-CoV-2 and its variants. This review proposes a set of modifications to existing regulatory requirements for mRNA products, based on a platform perspective for quality, manufacturing, preclinical, and clinical data. For the first time, we address development and potential regulatory requirements when the mRNA sequences and LNP composition vary in different products as well. In addition, we propose considerations for self-amplifying mRNA, individualised oncology mRNA products, and mRNA therapeutics. Providing a predictable development pathway for academic and commercial groups so that they can know in detail what product characterisation and data are required to develop a dossier for regulatory submission has many potential benefits. These include: reduced development and regulatory costs; faster consumer/patient access and more agile development of products in the face of pandemics; and for rare diseases where alternatives may not exist or to increase survival and the quality of life in cancer patients. Therefore, achieving consensus around platform approaches is both urgent and important. This approach with mRNA can be a template for similar platform frameworks for other therapeutics and vaccines to enable more efficient development and regulatory review.

Building pyramids against the evolutionary emergence of pathogens

Mutations allowing pathogens to escape host immunity promote the spread of infectious diseases in heterogeneous host populations and can lead to major epidemics. Understanding the conditions that slow down this evolution is key for the development of durable control strategies against pathogens. Here, we use theory and experiments to compare the efficacy of three strategies for the deployment of resistance: (i) a mixing strategy where the host population contains two single-resistant genotypes, (ii) a pyramiding strategy where the host carries a double-resistant genotype, (iii) a combining strategy where the host population is a mix of a single-resistant genotype and a double-resistant genotype. First, we use evolutionary epidemiology theory to clarify the interplay between demographic stochasticity and evolutionary dynamics to show that the pyramiding strategy always yields lower probability of evolutionary emergence. Second, we test experimentally these predictions with the introduction of bacteriophages into bacterial populations where we manipulated the diversity and the depth of immunity using a Clustered Regularly Interspaced Short Palindromic Repeats-CRISPR associated (CRISPR-Cas) system. These biological assays confirm that pyramiding multiple defences into the same host genotype and avoiding combination with single-defence genotypes is a robust way to reduce pathogen evolutionary emergence. The experimental validation of these theoretical recommendations has practical implications in various areas, including for the optimal deployment of resistance varieties in agriculture and for the design of durable vaccination strategies.

mRNA vaccines encoding computationally optimized hemagglutinin elicit protective antibodies against future antigenically drifted H1N1 and H3N2 influenza viruses isolated between 2018-2020

Background

The implementation of mRNA vaccines against COVID-19 has successfully validated the safety and efficacy of the platform, while at the same time revealing the potential for their applications against other infectious diseases. Traditional seasonal influenza vaccines often induce strain specific antibody responses that offer limited protection against antigenically drifted viruses, leading to reduced vaccine efficacy. Modern advances in viral surveillance and sequencing have led to the development of in-silico methodologies for generating computationally optimized broadly reactive antigens (COBRAs) to improve seasonal influenza vaccines.

Methods

In this study, immunologically naïve mice were intramuscularly vaccinated with mRNA encoding H1 and H3 COBRA hemagglutinins (HA) or wild-type (WT) influenza HAs encapsulated in lipid nanoparticles (LNPs).

Results

Mice vaccinated with H1 and H3 COBRA HA-encoding mRNA vaccines generated robust neutralizing serum antibody responses against more antigenically distinct contemporary and future drifted H1N1 and H3N2 influenza strains than those vaccinated with WT H1 and H3 HA-encoding mRNA vaccines. The H1 and H3 COBRA HA-encoding mRNA vaccines also prevented influenza illness, including severe disease in the mouse model against H1N1 and H3N2 viruses.

Conclusions

This study highlights the potential benefits of combining universal influenza antigen design technology with modern vaccine delivery platforms and exhibits how these vaccines can be advantageous over traditional WT vaccine antigens at eliciting superior protective antibody responses against a broader number of influenza virus isolates.

Recent Advances, Approaches and Challenges in the Development of Universal Influenza Vaccines

Every year, influenza virus infections cause significant morbidity and mortality worldwide. They pose a substantial burden of disease, in terms of not only health but also the economy. Owing to the ability of influenza viruses to continuously evolve, annual seasonal influenza vaccines are necessary as a prophylaxis. However, current influenza vaccines against seasonal strains have limited effectiveness and require yearly reformulation due to the virus undergoing antigenic drift or shift. Vaccine mismatches are common, conferring suboptimal protection against seasonal outbreaks, and the threat of the next pandemic continues to loom. Therefore, there is a great need to develop a universal influenza vaccine (UIV) capable of providing broad and durable protection against all influenza virus strains. In the quest to develop a UIV that would obviate the need for annual vaccination and formulation, a multitude of strategies is currently underway. Promising approaches include targeting the highly conserved epitopes of haemagglutinin (HA), neuraminidase (NA), M2 extracellular domain (M2e) and internal proteins of the influenza virus. The identification and characterization of broadly neutralizing antibodies (bnAbs) targeting conserved regions of the viral HA protein, in particular, have provided important insight into novel vaccine designs and platforms. This review discusses universal vaccine approaches presently under development, with an emphasis on those targeting the highly conserved stalk of the HA protein, recent technological advancements used and the future prospects of a UIV in terms of its advantages, developmental obstacles and potential shortcomings.

Zika Virus-A Reemerging Neurotropic Arbovirus Associated with Adverse Pregnancy Outcomes and Neuropathogenesis

Zika virus (ZIKV) is a reemerging flavivirus that is primarily spread through bites from infected mosquitos. It was first discovered in 1947 in sentinel monkeys in Uganda and has since been the cause of several outbreaks, primarily in tropical and subtropical areas. Unlike earlier outbreaks, the 2015-2016 epidemic in Brazil was characterized by the emergence of neurovirulent strains of ZIKV strains that could be sexually and perinatally transmitted, leading to the Congenital Zika Syndrome (CZS) in newborns, and Guillain-Barre Syndrome (GBS) along with encephalitis and meningitis in adults. The immune response elicited by ZIKV infection is highly effective and characterized by the induction of both ZIKV-specific neutralizing antibodies and robust effector CD8+ T cell responses. However, the structural similarities between ZIKV and Dengue virus (DENV) lead to the induction of cross-reactive immune responses that could potentially enhance subsequent DENV infection, which imposes a constraint on the development of a highly efficacious ZIKV vaccine. The isolation and characterization of antibodies capable of cross-neutralizing both ZIKV and DENV along with cross-reactive CD8+ T cell responses suggest that vaccine immunogens can be designed to overcome these constraints. Here we review the structural characteristics of ZIKV along with the evidence of neuropathogenesis associated with ZIKV infection and the complex nature of the immune response that is elicited by ZIKV infection.

PEDV-spike-protein-expressing mRNA vaccine protects piglets against PEDV challenge

Porcine epidemic diarrhea virus (PEDV), a swine enteropathogenic coronavirus, causes severe diarrhea in neonatal piglets, which is associated with a high mortality rate. Thus, developing effective and safe vaccines remains a top priority for controlling PEDV infection. Here, we designed two lipid nanoparticle (LNP)-encapsulated mRNA (mRNA-LNP) vaccines encoding either the full-length PEDV spike (S) protein or a multiepitope chimeric spike (Sm) protein. We found that the S mRNA-LNP vaccine was superior to the Sm mRNA-LNP vaccine at inducing antibody and cellular immune responses in mice. Evaluation of the immunogenicity and efficacy of the S mRNA vaccine in piglets confirmed that it induced robust PEDV-specific humoral and cellular immune responses in vivo. Importantly, the S mRNA-LNP vaccine not only protected actively immunized piglets against PEDV but also equipped neonatal piglets with effective passive anti-PEDV immunity in the form of colostrum-derived antibodies after the immunization of sows. Our findings suggest that the PEDV-S mRNA-LNP vaccine is a promising candidate for combating PEDV infection.IMPORTANCEPorcine epidemic diarrhea virus (PEDV) continues to harm the global swine industry. It is important to develop a highly effective vaccine to control PEDV infection. Here, we report a PEDV spike (S) mRNA vaccine that primes a potent antibody response and antigen-specific T-cell responses in immunized piglets. Active and passive immunization can protect piglets against PED following the virus challenge. This study highlights the efficiency of the PEDV-S mRNA vaccine and represents a viable approach for developing an efficient PEDV vaccine.

Self-Assembled Nanostructures Presenting Repetitive Arrays of Subunit Antigens for Enhanced Immune Response

Infectious diseases pose persistent threats to public health, demanding advanced vaccine technologies. Nanomaterial-based delivery systems offer promising solutions to enhance immunogenicity while minimizing reactogenicity. We introduce a self-assembled vaccine (SAV) platform employing antigen-polymer conjugates designed to facilitate robust immune responses. The SAVs exhibit efficient cellular uptake by dendritic cells (DCs) and macrophages, which are crucial players in the innate immune system. The high-density antigen presentation of this SAV platform enhances the affinity for DCs through multivalent recognition, significantly augmenting humoral immunity. SAV induced high levels of immunoglobulin G (IgG), IgG1, and IgG2a, suggesting that mature DCs efficiently induced B cell activation through multivalent antigen recognition. Universality was confirmed by applying it to respiratory viruses, showcasing its potential as a versatile vaccine platform. Furthermore, we have also demonstrated strong protection against influenza A virus infection with SAV containing hemagglutinin, which is used in influenza A virus subunit vaccines. The efficacy and adaptability of this nanostructured vaccine present potential utility in combating infectious diseases.

Lipid Nanoparticle (LNP) Delivery Carrier-Assisted Targeted Controlled Release mRNA Vaccines in Tumor Immunity

In recent years, lipid nanoparticles (LNPs) have attracted extensive attention in tumor immunotherapy. Targeting immune cells in cancer therapy has become a strategy of great research interest. mRNA vaccines are a potential choice for tumor immunotherapy, due to their ability to directly encode antigen proteins and stimulate a strong immune response. However, the mode of delivery and lack of stability of mRNA are key issues limiting its application. LNPs are an excellent mRNA delivery carrier, and their structural stability and biocompatibility make them an effective means for delivering mRNA to specific targets. This study summarizes the research progress in LNP delivery carrier-assisted targeted controlled release mRNA vaccines in tumor immunity. The role of LNPs in improving mRNA stability, immunogenicity, and targeting is discussed. This review aims to systematically summarize the latest research progress in LNP delivery carrier-assisted targeted controlled release mRNA vaccines in tumor immunity to provide new ideas and strategies for tumor immunotherapy, as well as to provide more effective treatment plans for patients.

An antibody-free evaluation of an mRNA COVID-19 vaccine

This manuscript describes the use of an analytical assay that combines transfection of mammalian cells and isotope dilution mass spectrometry (IDMS) for accurate quantification of antigen expression. Expired mRNA COVID-19 vaccine material was stored at 4 °C, room temperature (∼25 °C), and 56 °C over a period of 5 weeks. The same vaccine was also exposed to 5 freeze-thaw cycles. Every week, the spike protein antigenic expression in mammalian (BHK-21) cells was evaluated. Housekeeping proteins, β-actin and GAPDH, were simultaneously quantified to account for the variation in cell counts that occurs during maintenance and growth of cell cultures. Data show that vaccine stored at elevated temperatures results in reduced spike protein expression. Also, maintaining the vaccine in ultracold conditions or exposing the vaccine to freeze-thaw cycles had less effect on the vaccine's ability to produce the antigen in mammalian cells. We describe the use of IDMS as an antibody-free means to accurately quantify expressed protein from mammalian cells transfected with mRNA vaccine.

Transmission-Blocking Vaccines against Schistosomiasis Japonica

Control of schistosomiasis japonica, endemic in Asia, including the Philippines, China, and Indonesia, is extremely challenging. Schistosoma japonicum is a highly pathogenic helminth parasite, with disease arising predominantly from an immune reaction to entrapped parasite eggs in tissues. Females of this species can generate 1000-2200 eggs per day, which is about 3- to 15-fold greater than the egg output of other schistosome species. Bovines (water buffalo and cattle) are the predominant definitive hosts and are estimated to generate up to 90% of parasite eggs released into the environment in rural endemic areas where these hosts and humans are present. Here, we highlight the necessity of developing veterinary transmission-blocking vaccines for bovines to better control the disease and review potential vaccine candidates. We also point out that the approach to producing efficacious transmission-blocking animal-based vaccines before moving on to human vaccines is crucial. This will result in effective and feasible public health outcomes in agreement with the One Health concept to achieve optimum health for people, animals, and the environment. Indeed, incorporating a veterinary-based transmission vaccine, coupled with interventions such as human mass drug administration, improved sanitation and hygiene, health education, and snail control, would be invaluable to eliminating zoonotic schistosomiasis.

Innovative Genoceuticals in Human Gene Therapy Solutions: Challenges and Safe Clinical Trials of Orphan Gene Therapy Products

The success of gene therapy attempts is controversial and inconclusive. Currently, it is popular among the public, the scientific community, and manufacturers of Gene Therapy Medical Products. In the absence of any remedy or treatment options available for untreatable inborn metabolic orphan or genetic diseases, cancer, or brain diseases, gene therapy treatment by genoceuticals and T-cells for gene editing and recovery remains the preferred choice as the last hope. A new concept of "Genoceutical Gene Therapy" by using orphan 'nucleic acid-based therapy' aims to introduce scientific principles of treating acquired tissue damage and rare diseases. These Orphan Genoceuticals provide new scope for the 'genodrug' development and evaluation of genoceuticals and gene products for ideal 'gene therapy' use in humans with marketing authorization application (MAA). This perspective study focuses on the quality control, safety, and efficacy requirements of using 'nucleic acid-based and human cell-based new gene therapy' genoceutical products to set scientific advice on genoceutical-based 'orphan genodrug' design for clinical trials as per Western and European guidelines. The ethical Western FDA and European EMA guidelines suggest stringent legal and technical requirements on genoceutical medical products or orphan genodrug use for other countries to frame their own guidelines. The introduction section proposes lessknown 'orphan drug-like' properties of modified RNA/DNA, human cell origin gene therapy medical products, and their transgene products. The clinical trial section explores the genoceutical sources, FDA/EMA approvals for genoceutical efficacy criteria with challenges, and ethical guidelines relating to gene therapy of specific rare metabolic, cancer and neurological diseases. The safety evaluation of approved genoceuticals or orphan drugs is highlighted with basic principles and 'genovigilance' requirements (to observe any adverse effects, side effects, developed signs/symptoms) to establish their therapeutic use. Current European Union and Food and Drug Administration guidelines continuously administer fast-track regulatory legal framework from time to time, and they monitor the success of gene therapy medical product efficacy and safety. Moreover, new ethical guidelines on 'orphan drug-like genoceuticals' are updated for biodistribution of the vector, genokinetics studies of the transgene product, requirements for efficacy studies in industries for market authorization, and clinical safety endpoints with their specific concerns in clinical trials or public use.

An mRNA-based broad-spectrum vaccine candidate confers cross-protection against heterosubtypic influenza A viruses

Influenza virus is a prominent cause of respiratory illness in humans. Current influenza vaccines offer strain-specific immunity, while provide limited protection against drifted strains. Broad-spectrum influenza vaccines can induce broad and long-term immunity, and thus are regarded as a future direction for the development of next-generation influenza vaccines. In this study, we have conceptualized a novel mRNA-based multi-antigen influenza vaccine consisting of three conserved antigens of influenza A virus, including the ectodomain of the M2 ion channel (M2e), the long alpha helix of haemagglutinin stalk region (LAH), and nucleoprotein (NP). The vaccine design aims to enhance its potency and promote the development of a future broad-spectrum influenza vaccine. Our mRNA-based vaccine demonstrated potent humoral and cellular responses throughout the time points of the murine model, inducing viral neutralizing antibodies, antibody-dependent cell cytotoxicity effect mediating antibodies and cross-reactive CD8+ T cell immune responses. The vaccine conferred broad protection against H1N1, H3N2, and H9N2 viruses. Moreover, the single-cell transcriptional profiling of T cells in the spleens of vaccinated mice revealed that the mRNA-based vaccine significantly promoted CD8+ T cells and memory T cells by prime-boost immunization. Our results suggest that the mRNA-based influenza vaccine encoding conserved proteins is a promising approach for eliciting broadly protective humoral and cellular immunity against various influenza viruses.

Harnessing synthetic biology for advancing RNA therapeutics and vaccine design

Recent global events have drawn into focus the diversity of options for combatting disease across a spectrum of prophylactic and therapeutic approaches. The recent success of the mRNA-based COVID-19 vaccines has paved the way for RNA-based treatments to revolutionize the pharmaceutical industry. However, historical treatment options are continuously updated and reimagined in the context of novel technical developments, such as those facilitated through the application of synthetic biology. When it comes to the development of genetic forms of therapies and vaccines, synthetic biology offers diverse tools and approaches to influence the content, dosage, and breadth of treatment with the prospect of economic advantage provided in time and cost benefits. This can be achieved by utilizing the broad tools within this discipline to enhance the functionality and efficacy of pharmaceutical agent sequences. This review will describe how synthetic biology principles can augment RNA-based treatments through optimizing not only the vaccine antigen, therapeutic construct, therapeutic activity, and delivery vector. The enhancement of RNA vaccine technology through implementing synthetic biology has the potential to shape the next generation of vaccines and therapeutics.

An immune-enhanced multivalent DNA nanovaccine to prevent H7 and H9 avian influenza virus in mice

H7 avian influenza virus has caused multiple human infections and poses a severe public health threat. In response to the highly variable nature of AIVs, a novel, easily regenerated DNA vaccine has great potential in treating or preventing avian influenza pandemics. Nevertheless, DNA vaccines have many disadvantages, such as weak immunogenicity and poor in vivo delivery. To further characterize and solve these issues and develop a novel H7 AIV DNA vaccine with enhanced stability and immunogenicity, we constructed nine AIV DNA plasmids, and the immunogenicity screened showed that mice immunized with pβH7N2SH9 elicited stronger hemagglutination-inhibiting (HI) antibodies than other eight plasmid DNAs. Then, to address the susceptibility to degradation and low transfection rate of DNA vaccine in vivo, we developed pβH7N2SH9/DGL NPs by encapsulating the pβH7N2SH9 within the dendrigraft poly-l-lysines nanoparticles. As expected, these NPs exhibited excellent physical and chemical properties, were capable of promote lymphocyte proliferation, and induce stronger humoral and cellular responses than the naked pβH7N2SH9, including higher levels of HI antibodies than naked pβH7N2SH9, as well as the production of cytokines, namely, IL-2, IFN-α. Taken together, our results suggest that the construction of an immune-enhanced H7-AIV DNA nanovaccine may be a promising strategy against most influenza viruses.

Seasonal quadrivalent mRNA vaccine prevents and mitigates influenza infection

Annually, seasonal influenza is responsible for millions of infections and hundreds of thousands of deaths. The current method for managing influenza is vaccination using a standardized amount of the influenza virus' primary surface antigen, hemagglutinin (HA), as the intended target of the immune response. This vaccination strategy results in vaccines with variable efficacy year to year due to antigenic drift of HA, which can be further exacerbated by manufacturing processes optimizing growth of vaccine virus in eggs. Due to these limitations, alternative vaccine platforms are actively being explored to improve influenza vaccine efficacy, including cell-based, recombinant protein, and mRNA vaccines. mRNA's rapid, in vitro production makes it an appealing platform for influenza vaccination, and the success of SARS-CoV-2 mRNA vaccines in the clinic has encouraged the development of mRNA vaccines for other pathogens. Here, the immunogenicity and protective efficacy of a quadrivalent mRNA vaccine encoding HA from four seasonal influenza viruses, A/California/07/2009 (H1N1), A/Hong Kong/4801/2014 (H3N2), B/Brisbane/60/2008 (B-Victoria lineage), and B/Phuket/3073/2013 (B-Yamagata lineage), was evaluated. In mice, a 120 μg total dose of this quadrivalent mRNA vaccine induced robust antibody titers against each subtype that were commensurate with titers when each antigen was administered alone. Following A/California/04/2009 challenge, mice were fully protected from morbidity and mortality, even at doses as low as 1 μg of each antigen. Additionally, a single administration of 10 μg of quadrivalent mRNA was sufficient to prevent weight loss caused by A/California/04/2009. These results support the promise of this mRNA vaccine for prevention and mitigation of influenza vaccine.

Understanding structure activity relationships of Good HEPES lipids for lipid nanoparticle mRNA vaccine applications

Lipid nanoparticles (LNPs) have shown great promise as delivery vehicles to transport messenger ribonucleic acid (mRNA) into cells and act as vaccines for infectious diseases including COVID-19 and influenza. The ionizable lipid incorporated within the LNP is known to be one of the main driving factors for potency and tolerability. Herein, we describe a novel family of ionizable lipids synthesized with a piperazine core derived from the HEPES Good buffer. These ionizable lipids have unique asymmetric tails and two dissimilar degradable moieties incorporated within the structure. Lipids tails of varying lengths, degrees of unsaturation, branching, and the inclusion of additional ester moieties were evaluated for protein expression. We observed several key lipid structure activity relationships that correlated with improved protein production in vivo, including lipid tails of 12 carbons on the ester side and the effect of carbon spacing on the disulfide arm of the lipids. Differences in LNP physical characteristics were observed for lipids containing an extra ester moiety. The LNP structure and lipid bilayer packing, visualized through Cryo-TEM, affected the amount of protein produced in vivo. In non-human primates, the Good HEPES LNPs formulated with an mRNA encoding an influenza hemagglutinin (HA) antigen successfully generated functional HA inhibition (HAI) antibody titers comparable to the industry standards MC3 and SM-102 LNPs, demonstrating their promise as a potential vaccine.

Understanding the Global Burden of Influenza in Adults Aged 18-64 years: A Systematic Literature Review from 2012 to 2022

INTRODUCTION

Adults aged 18-64 years comprise most of the working population, meaning that influenza infection can be disruptive, causing prolonged absence from the workplace, and reduced productivity and the ability to care for dependents. Influenza vaccine uptake is relatively low, even among the older adults in this population (i.e., aged 50-64 years), reflecting a lack of perceived need for vaccination. This systematic literature review (SLR) aimed to characterize the global burden of influenza in the 18-64 years population.

METHODS

An electronic database search was conducted and supplemented with conference and gray literature searches. Eligible studies described at least one of clinical, humanistic, or economic outcomes in adults aged 18-64 years and conducted across several global regions. Included studies were published in English, between January 1, 2012, and September 20, 2022.

RESULTS

A total of 40 publications were included, with clinical, humanistic, and economic outcomes reported in 39, 5, and 15, respectively. Risk of influenza-associated clinical outcomes were reported to increase with age among the 18-64 years population, including hospitalizations (Yamana et al. in Intern Med 60:3401-3408, 2021; Derqui et al. in Influenza Other Respir Viruses 16:862-872, 2022; Fuller et al. in Influenza Other Respir Viruses 16:265-275, 2022; Ortiz et al. in Crit Care Med 42:2325-2332, 2014; Yandrapalli et al. in Ann Transl Med 6:318, 2018; Zimmerman et al. in Influenza Other Respir Viruses 16:1133-1140, 2022). ICU admissions, mortality, ER/outpatient visits, and use of mechanical ventilation were recorded. Adults aged 18-64 years with underlying comorbidities were at higher risk of influenza-related hospitalizations, ICU admission, and mortality than otherwise healthy individuals. Length of hospital stay increased with age, although a lack of stratification across other economic outcomes prevented identification of further trends across age groups.

CONCLUSIONS

High levels of hospitalization and outpatient visits demonstrated a clinical influenza-associated burden on patients and healthcare systems, which is exacerbated by comorbidities. Considering the size and breadth of the general population aged 18-64 years, the limited humanistic and economic findings of this SLR likely reflect an underreported burden. Greater investigation into indirect costs and prolonged absenteeism associated with influenza infection is required to fully understand the economic burden in this population.

An RNA-Scaffold Protein Subunit Vaccine for Nasal Immunization

Developing recombinant proteins as nasal vaccines for inducing systemic and mucosal immunity against respiratory viruses is promising. However, additional adjuvants are required to overcome the low immunogenicity of protein antigens. Here, a self-adjuvanted protein-RNA ribonucleoprotein vaccine was developed and found to be an effective nasal vaccine in mice and the SARS-CoV-2 infection model. The vaccine consisted of spike RBD (as an antigen), nucleoprotein (as an adaptor), and ssRNA (as an adjuvant and RNA scaffold). This combination robustly induced mucosal IgA, neutralizing antibodies and activated multifunctional T-cells, while also providing sterilizing immunity against live virus challenge. In addition, high-resolution scRNA-seq analysis highlighted airway-resident immune cells profile during prime-boost immunization. The vaccine also possesses modularity (antigen/adaptor/RNA scaffold) and can be made to target other viruses. This protein-RNA ribonucleoprotein vaccine is a novel and promising approach for developing safe and potent nasal vaccines to combat respiratory virus infections.

mRNA vaccines in disease prevention and treatment

mRNA vaccines have emerged as highly effective strategies in the prophylaxis and treatment of diseases, thanks largely although not totally to their extraordinary performance in recent years against the worldwide plague COVID-19. The huge superiority of mRNA vaccines regarding their efficacy, safety, and large-scale manufacture encourages pharmaceutical industries and biotechnology companies to expand their application to a diverse array of diseases, despite the nonnegligible problems in design, fabrication, and mode of administration. This review delves into the technical underpinnings of mRNA vaccines, covering mRNA design, synthesis, delivery, and adjuvant technologies. Moreover, this review presents a systematic retrospective analysis in a logical and well-organized manner, shedding light on representative mRNA vaccines employed in various diseases. The scope extends across infectious diseases, cancers, immunological diseases, tissue damages, and rare diseases, showcasing the versatility and potential of mRNA vaccines in diverse therapeutic areas. Furthermore, this review engages in a prospective discussion regarding the current challenge and potential direction for the advancement and utilization of mRNA vaccines. Overall, this comprehensive review serves as a valuable resource for researchers, clinicians, and industry professionals, providing a comprehensive understanding of the technical aspects, historical context, and future prospects of mRNA vaccines in the fight against various diseases.

Safety and immunogenicity of a phase 1/2 randomized clinical trial of a quadrivalent, mRNA-based seasonal influenza vaccine (mRNA-1010) in healthy adults: interim analysis

Despite vaccine availability, influenza remains a substantial global public health concern. Here, we report interim findings on the primary and secondary objectives of the safety, reactogenicity, and humoral immunogenicity of a quadrivalent messenger RNA (mRNA) vaccine against seasonal influenza, mRNA-1010, from the first 2 parts of a 3-part, first-in-human, phase 1/2 clinical trial in healthy adults aged ≥18 years (NCT04956575). In the placebo-controlled Part 1, a single dose of mRNA-1010 (50 µg, 100 µg, or 200 µg) elicited hemagglutination inhibition (HAI) titers against vaccine-matched strains. In the active-comparator-controlled Part 2, mRNA-1010 (25 µg, 50 µg, or 100 µg) elicited higher HAI titers than a standard dose, inactivated seasonal influenza vaccine for influenza A strains and comparable HAI titers for influenza B strains. No safety concerns were identified; solicited adverse reactions were dose-dependent and more frequent after receipt of mRNA-1010 than the active comparator. These interim data support continued development of mRNA-1010.

The impact of nucleoside base modification in mRNA vaccine is influenced by the chemistry of its lipid nanoparticle delivery system

The use of modified nucleosides is an important approach to mitigate the intrinsic immunostimulatory activity of exogenous mRNA and to increase its translation for mRNA therapeutic applications. However, for vaccine applications, the intrinsic immunostimulatory nature of unmodified mRNA could help induce productive immunity. Additionally, the ionizable lipid nanoparticles (LNPs) used to deliver mRNA vaccines can possess immunostimulatory properties that may influence the impact of nucleoside modification. Here we show that uridine replacement with N1-methylpseudouridine in an mRNA vaccine encoding influenza hemagglutinin had a significant impact on the induction of innate chemokines/cytokines and a positive impact on the induction of functional antibody titers in mice and macaques when MC3 or KC2 LNPs were used as delivery systems, while it impacted only minimally the titers obtained with L319 LNPs, indicating that the impact of nucleoside modification on mRNA vaccine efficacy varies with LNP composition. In line with previous observations, we noticed an inverse correlation between the induction of high innate IFN-α titers in the macaques and antigen-specific immune responses. Furthermore, and consistent with the species specificity of pathogen recognition receptors, we found that the effect of uridine replacement did not strictly translate from mice to non-human primates.