mRNA vaccines - a new era in vaccinology

Induction of protective immune responses at respiratory mucosal sites

Many pathogens enter the host through mucosal sites. Thus, interfering with pathogen entry through local neutralization at mucosal sites therefore is an effective strategy for preventing disease. Mucosally administered vaccines have the potential to induce protective immune responses at mucosal sites. This manuscript delves into some of the latest developments in mucosal vaccination, particularly focusing on advancements in adjuvant technologies and the role of these adjuvants in enhancing vaccine efficacy against respiratory pathogens. It highlights the anatomical and immunological complexities of the respiratory mucosal immune system, emphasizing the significance of mucosal secretory IgA and tissue-resident memory T cells in local immune responses. We further discuss the differences between immune responses induced through traditional parenteral vaccination approaches vs. mucosal administration strategies, and explore the protective advantages offered by immunization through mucosal routes.

Long-term stability and immunogenicity of lipid nanoparticle COVID-19 mRNA vaccine is affected by particle size

Messenger ribonucleic acid (mRNA) technology has been rapidly applied for the development of the COVID-19 vaccine. However, naked mRNA itself is inherently unstable. Lipid nanoparticles (LNPs) protect mRNAs from extracellular ribonucleases and facilitate mRNA trafficking. For mRNA vaccines, antigen-presenting cells utilize LNPs through uptake to elicit antigen-specific immunity. There are reports on the impact of various physical characteristics of LNPs, particularly those with sizes less than 200 nm, especially 50 to 150 nm, on the overall stability and protective efficacy of mRNA vaccines. To address this, a single change in the size of LNPs using the same mRNA stock solution was assessed for the physicochemical characterization of the resulting mRNA-LNPs vaccine, along with the evaluation of their protective efficacy. Particles of smaller sizes generally disperse more effectively in solutions, with minimized occurrence of particle precipitation and aggregation. Here, we demonstrate that the vaccine containing 80-100 nm mRNA-LNPs showed the best stability and protection at 4°C and -20°C. Furthermore, we can conclude that freezing the vaccine at -20°C is more appropriate for maintaining stability over the long term. This effort is poised to provide a scientific basis for improving the quality of ongoing mRNA vaccine endeavors and providing information on the development of novel products.

Seasonal influenza vaccine performance and the potential benefits of mRNA vaccines

Influenza remains a public health threat, partly due to suboptimal effectiveness of vaccines. One factor impacting vaccine effectiveness is strain mismatch, occurring when vaccines no longer match circulating strains due to antigenic drift or the incorporation of inadvertent (eg, egg-adaptive) mutations during vaccine manufacturing. In this review, we summarize the evidence for antigenic drift of circulating viruses and/or egg-adaptive mutations occurring in vaccine strains during the 2011-2020 influenza seasons. Evidence suggests that antigenic drift led to vaccine mismatch during four seasons and that egg-adaptive mutations caused vaccine mismatch during six seasons. These findings highlight the need for alternative vaccine development platforms. Recently, vaccines based on mRNA technology have demonstrated efficacy against SARS-CoV-2 and respiratory syncytial virus and are under clinical evaluation for seasonal influenza. We discuss the potential for mRNA vaccines to address strain mismatch, as well as new multi-component strategies using the mRNA platform to improve vaccine effectiveness.

Immunotherapy and delivery systems for melanoma

Melanoma is a highly malignant tumor of melanocyte origin that is prone to early metastasis and has a very poor prognosis. Early melanoma treatment modalities are mainly surgical, and treatment strategies for advanced or metastatic melanoma contain chemotherapy, radiotherapy, targeted therapy and immunotherapy. The efficacy of chemotherapy and radiotherapy has been unsatisfactory due to low sensitivity and strong toxic side effects. And targeted therapy is prone to drug resistance, so its clinical application is limited. Melanoma has always been the leader of immunotherapy for solid tumors, and how to maximize the role of immunotherapy and how to implement immunotherapy more accurately are still urgent to be explored. This review summarizes the common immunotherapies and applications for melanoma, illustrates the current research status of melanoma immunotherapy delivery systems, and discusses the advantages and disadvantages of each delivery system and its prospects for clinical application.

Recent progress in mRNA cancer vaccines

The research and development of messenger RNA (mRNA) cancer vaccines have gradually overcome numerous challenges through the application of personalized cancer antigens, structural optimization of mRNA, and the development of alternative RNA-based vectors and efficient targeted delivery vectors. Clinical trials are currently underway for various cancer vaccines that encode tumor-associated antigens (TAAs), tumor-specific antigens (TSAs), or immunomodulators. In this paper, we summarize the optimization of mRNA and the emergence of RNA-based expression vectors in cancer vaccines. We begin by reviewing the advancement and utilization of state-of-the-art targeted lipid nanoparticles (LNPs), followed by presenting the primary classifications and clinical applications of mRNA cancer vaccines. Collectively, mRNA vaccines are emerging as a central focus in cancer immunotherapy, offering the potential to address multiple challenges in cancer treatment, either as standalone therapies or in combination with current cancer treatments.

Development of mRNA rabies vaccines

Rabies, primarily transmitted to humans by dogs (accounting for 99% of cases). Once rabies occurs, its mortality rate is approximately 100%. Post-exposure prophylaxis (PEP) is critical for preventing the onset of rabies after exposure to rabid animals, and vaccination is a pivotal element of PEP. However, high costs and complex immunization protocols have led to poor adherence to rabies vaccinations. Consequently, there is an urgent need to develop new rabies vaccines that are safe, highly immunogenic, and cost-effective to improve compliance and effectively prevent rabies. In recent years, mRNA vaccines have made significant progress in the structural modification and optimization of delivery systems. Various mRNA vaccines are currently undergoing clinical trials, positioning them as viable alternatives to the traditional rabies vaccines. In this article, we discuss a novel mRNA rabies vaccine currently undergoing clinical and preclinical testing, and evaluate its potential to replace existing vaccines.

Bibliometric analysis of dendritic cell-based vaccines over the past 15 years

Dendritic cells, which are crucial for inducing T-cell responses, are pivotal in current immunotherapy strategies aiming to replenish depleted T cells within the tumor microenvironment to combat tumors. Consequently, dendritic cell vaccine-based cancer therapies have garnered significant attention. Through bibliometric analysis, we examined research trends in this field. We searched the Web of Science core database and identified 16,476 articles on dendritic cell-based vaccines published from January 1, 2009, to December 30, 2023. The United States leads in this research domain, with Emory University being a prominent collaborator. The Journal of Immunology is the primary publication outlet, and Banchereau, J emerges as the most influential author. Recent hot keywords include nanoparticle, delivery, cancer vaccine, and clinical trial, indicating that cancer immunotherapy research, especially dendritic cell-based vaccines, is poised to become a future trend and hotspot.

Safety and efficiency of COVID-19 vaccine in North Africa

Background In the absence of a specific treatment for COVID-19, preventive measures have been implemented to control this pandemic and vaccination is one of them. However, it is crucial to verify the safety and efficiency of every vaccine. The aim was to determinate the predictive factors of side effects and reinfection after COVID-19 vaccine. Methods A cross-sectional study was conducted in February 2022 among Tunisians infected with COVID-19 between March 2020 and February 2022, using an online self-administered questionnaire. We conducted univariate and multivariate analyses using binary stepwise logistic regression. Results A total of 1541 was selected from 1911 individuals. Comorbidities affected a quarter of the population (22.3%). Before the initial infection, 39.3% had received full vaccination, and 8.7% had received partial vaccination. By February 2022, the majority (82.9%) had received at least two vaccine doses. The reinfection rate was 30.6%. All vaccines prior to the first infection was identified as a protective factor against reinfection. Inactivated virus vaccinations were less likely to induce adverse effects. Conclusion ach vaccine has its own set of advantages and disadvantages: mRNA-based vaccines had a higher incidence of side effects but all vaccines provided better protection against reinfection.

A long-term stable cold-chain-friendly HIV mRNA vaccine encoding multi-epitope viral protease cleavage site immunogens inducing immunogen-specific protective T cell immunity

The lack of success in clinical trials for HIV vaccines highlights the need to explore novel strategies for vaccine development. Research on highly exposed seronegative (HESN) HIV-resistant Kenyan female sex workers revealed naturally protective immunity is correlated with a focused immune response mediated by virus-specific CD8 T cells. Further studies indicated that the immune response is unconventionally focused on highly conserved sequences around HIV viral protease cleavage sites (VPCS). Thus, taking an unconventional approach to HIV vaccine development, we designed lipid nanoparticles loaded with mRNA that encodes multi-epitopes of VPCS (MEVPCS-mRNA LNP), a strategic design to boost antigen presentation by dendritic cells, promoting effective cellular immunity. Furthermore, we developed a novel cold-chain compatible mRNA LNP formulation, ensuring long-term stability and compatibility with cold-chain storage/transport, widening accessibility of mRNA LNP vaccine in low-income countries. The in-vivo mouse study demonstrated that the vaccinated group generated VPCS-specific CD8 memory T cells, both systemically and at mucosal sites of viral entry. The MEVPCS-mRNA LNP vaccine-induced CD8 T cell immunity closely resembled that of the HESN group and displayed a polyfunctional profile. Notably, it induced minimal to no activation of CD4 T cells. This proof-of-concept study underscores the potential of the MEVPCS-mRNA LNP vaccine in eliciting CD8 T cell memory specific to the highly conserved multiple VPCS, consequently having a broad coverage in human populations and limiting viral escape mutation. The MEVPCS-mRNA LNP vaccine holds promise as a candidate for an effective prophylactic HIV vaccine.

Recombinant T7 RNA polymerase production using ClearColi BL21(DE3) and animal-free media for in vitro transcription

In vitro transcription (IVT) using T7 RNA polymerase (RNAP) is integral to RNA research, yet producing this enzyme in E. coli presents challenges regarding endotoxins and animal-sourced toxins. This study demonstrates the viable production and characterization of T7 RNAP using ClearColi BL21(DE3) (an endotoxin-free E. coli strain) and animal-free media. Compared to BL21(DE3) with animal-free medium, soluble T7 RNAP expression is ~50% lower in ClearColi BL21(DE3). Optimal soluble T7 RNAP expression in flask fermentation is achieved through the design of experiments (DoE). Specification and functional testing showed that the endotoxin-free T7 RNAP has comparable activity to conventional T7 RNAP. After Ni-NTA purification, endotoxin levels were approximately 109-fold lower than T7 RNAP from BL21(DE3) with animal-free medium. Furthermore, a full factorial DoE created an optimal IVT system that maximized mRNA yield from the endotoxin-free and animal-free T7 RNAP. This work addresses critical challenges in recombinant T7 RNAP production through innovative host and medium combinations, avoided endotoxin risks and animal-derived toxins. Together with an optimized IVT reaction system, this study represents a significant advance for safe and reliable reagent manufacturing and RNA therapeutics. KEY POINTS: • Optimized IVT system maximizes mRNA yields, enabling the synthesis of long RNAs. • Novel production method yields endotoxin-free and animal-free T7 RNAP. • The T7 RNAP has equivalent specifications and function to conventional T7 RNAP.

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.

A statistical-physics approach for codon usage optimisation

The concept of "codon optimisation" involves adjusting the coding sequence of a target protein to account for the inherent codon preferences of a host species and maximise protein expression in that species. However, there is still a lack of consensus on the most effective approach to achieve optimal results. Existing methods typically depend on heuristic combinations of different variables, leaving the user with the final choice of the sequence hit. In this study, we propose a new statistical-physics model for codon optimisation. This model, called the Nearest-Neighbour interaction (NN) model, links the probability of any given codon sequence to the "interactions" between neighbouring codons. We used the model to design codon sequences for different proteins of interest, and we compared our sequences with the predictions of some commercial tools. In order to assess the importance of the pair interactions, we additionally compared the NN model with a simpler method (Ind) that disregards interactions. It was observed that the NN method yielded similar Codon Adaptation Index (CAI) values to those obtained by other commercial algorithms, despite the fact that CAI was not explicitly considered in the algorithm. By utilising both the NN and Ind methods to optimise the reporter protein luciferase, and then analysing the translation performance in human cell lines and in a mouse model, we found that the NN approach yielded the highest protein expression in vivo. Consequently, we propose that the NN model may prove advantageous in biotechnological applications, such as heterologous protein expression or mRNA-based therapies.

Development of multi-epitope mRNA vaccine against Clostridioides difficile using reverse vaccinology and immunoinformatics approaches

Clostridioides difficile (C. difficile), as the major pathogen of diarrhea in healthcare settings, has become increasingly prevalent within community populations, resulting in significant morbidity and mortality. However, the therapeutic options for Clostridioides difficile infection (CDI) remain limited, and as of now, no authorized vaccine is available to combat this disease. Therefore, the development of a novel vaccine against C. difficile is of paramount importance. In our study, the complete proteome sequences of 118 strains of C. difficile were downloaded and analyzed. We found four antigenic proteins that were highly conserved and can be used for epitope identification. We designed two vaccines, WLcd1 and WLcd2, that contain the ideal T-cell and B-cell epitopes, adjuvants, and the pan HLA DR-binding epitope (PADRE) sequences. The biophysical and chemical assessments of these vaccine candidates indicated that they were suitable for immunogenic applications. Molecular docking analyses revealed that WLcd1 bonded with higher affinity to Toll-like receptors (TLRs) than WLcd2. Furthermore, molecular dynamics (MD) simulations, performed using Gmx_MMPBSA v1.56, confirmed the binding stability of WLcd1 with TLR2 and TLR4. The preliminary findings suggested that this multi-epitope vaccine could be a promising candidate for protection against CDI; however, experimental studies are necessary to confirm these predictions.

Spleen-Targeted mRNA Vaccine Doped with Manganese Adjuvant for Robust Anticancer Immunity In Vivo

The successful application of mRNA vaccines in preventing and treating infectious diseases highlights their potential as therapeutic vaccines for cancer treatment. However, unlike infectious diseases, effective antitumor therapy, particularly for solid tumors, necessitates the activation of more powerful cellular and humoral immunity to achieve clinical efficacy. Here, we report a spleen-targeted mRNA vaccine (Mn@mRNA-LNP) designed to deliver tumor antigen-encoding mRNA and manganese adjuvant (Mn2+) simultaneously to dendritic cells (DCs) in the spleen. This delivery system promotes DC maturation and surface antigen presentation and stimulates the production of cytotoxic T cells. Additionally, Mn2+ codelivered in the system serves as a safe and effective immune adjuvant, activating the stimulator of interferon genes (STING) signaling pathway and promoting the secretion of type I interferon, further enhancing the antigen-specific T cell responses. Mn@mRNA-LNP effectively inhibits tumor progression in established melanoma and colon tumor models as well as in a model of tumor recurrence after resection. Notably, the combination of Mn@mRNA-LNP with immune checkpoint inhibitors further enhances complete tumor suppression and prolonged the overall survival in mice. Overall, this "All-in-One" mRNA vaccine significantly boosts antitumor immunity responses by improving spleen targeting and immune activation, providing an attractive strategy for the future clinical translation of therapeutic mRNA vaccines.

High-Throughput Algorithmic Optimization of In Vitro Transcription for SARS-CoV-2 mRNA Vaccine Production

The in vitro transcription (IVT) of messenger ribonucleic acid (mRNA) from the linearized deoxyribonucleic acid (DNA) template of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Delta variant (B.1.617.2) was optimized for total mRNA yield and purity (by percent intact mRNA) utilizing machine learning in conjunction with automated, high-throughput liquid handling technology. An iterative Bayesian optimization approach successfully optimized 11 critical process parameters in 42 reactions across 5 experimental rounds. Once the optimized conditions were achieved, an automated, high-throughput screen was conducted to evaluate commercially available T7 RNA polymerases for rate and quality of mRNA production. Final conditions showed a 12% yield improvement and a 50% reduction in reaction time, while simultaneously significantly decreasing (up to 44% reduction) the use of expensive reagents. This novel platform offers a powerful new approach for optimizing IVT reactions for mRNA production.

Oxaliplatin lipidated prodrug synergistically enhances the anti-colorectal cancer effect of IL12 mRNA

Colorectal cancer (CRC) is the fourth most common cancer in the world, with the second highest incidence rate after lung cancer. Oxaliplatin (OXA) is a broad-spectrum anti-tumor agent with significant therapeutic efficacy in colorectal cancer, and as a divalent platinum analog, it is not selective in its distribution in the body and has systemic toxicity with continued use. Interleukin-12 (IL12) is an immunostimulatory cytokine with cytokine monotherapy that has made advances in the fight against cancer, limiting the clinical use of cytokines due to severe toxicity. Here, we introduced a long alkyl chain and N-methyl-2,2-diaminodiethylamine to the ligand of OXA to obtain OXA-LIP, which effectively reduces its toxicity and improves the uptake of the drug by tumor cells. We successfully constructed IL12 mRNA and used LNPs to deliver IL12 mRNA, and in vivo pharmacodynamic studies demonstrated that OXA-LIP combined with IL12 mRNA had better tumor inhibition and higher biosafety. In addition, it was investigated by pharmacokinetic experiments that the OXA-LIP drug could accumulate in nude mice at the tumor site, which prolonged the half-life and enhanced the anti-tumor efficiency of OXA. It is hoped that these results will provide an important reference for the subsequent research and development of OXA-LIP with IL12 mRNA, as well as provide new therapeutic approaches for the treatment of colon cancer.

mRNA vaccines for infectious diseases - advances, challenges and opportunities

The concept of mRNA-based vaccines emerged more than three decades ago. Groundbreaking discoveries and technological advancements over the past 20 years have resolved the major roadblocks that initially delayed application of this new vaccine modality. The rapid development of nucleoside-modified COVID-19 mRNA vaccines demonstrated that this immunization platform is easy to develop, has an acceptable safety profile and can be produced at a large scale. The flexibility and ease of antigen design have enabled mRNA vaccines to enter development for a wide range of viruses as well as for various bacteria and parasites. However, gaps in our knowledge limit the development of next-generation mRNA vaccines with increased potency and safety. A deeper understanding of the mechanisms of action of mRNA vaccines, application of novel technologies enabling rational antigen design, and innovative vaccine delivery strategies and vaccination regimens will likely yield potent novel vaccines against a wide range of pathogens.

Tetradecanol-wrapped, CpG-loaded porous Prussian blue nanoimmunomodulator for photothermal-responsive in situ anti-tumor vaccine-like immunotherapy

Therapeutic vaccine becomes a promising strategy to fight cancer by enhancing and sustaining specific anti-tumor immune responses. However, its efficacy is often impeded by low immunogenicity, the immunosuppressive tumor microenvironment (TME), and immune-related adverse events. Herein, we introduce 1-tetradecanol (TD)-wrapped, CpG-loaded porous Prussian blue nanoparticles (pPBNPs-CpG@TD) as a nanoimmunomodulator to initiate photothermal-induced immunogenic cell death (ICD) and photothermal-responsive release of CpG for augmenting the ICD effect. It was revealed that the dual-photothermal action significantly potentiated the in situ anti-tumor vaccine-like immunotherapy in terms of enhanced immunogenicity, promoted dendritic cell maturation, and increased T lymphocyte infiltration, consequently eliciting a robust immune response for inhibiting both primary and rechallenge tumors on a subcutaneous 4T1 tumor-bearing mouse model. The development and use of photoactive nanoimmunomodulators represents a novel and effective strategy to boost immunogenicity and counteract immunosuppressive TME, marking a significant advancement in the realm of ICD-driven in situ anti-tumor vaccine-like immunotherapy.

LNP-mRNA vaccine prevents type 1 diabetes in non-obese diabetes mice

Islet-antigen-specific tolerization is a key goal of experimental immunotherapies for type 1 diabetes. mRNA-based vaccines have demonstrated the feasibility of RNA delivery in inducing antigen tolerance in autoimmune diseases. In this study, mRNA vaccine, encoded tandem glutamic acid decarboxylase 65 (GAD65) epitopes and cholera toxin B subunit (CTB-GADIII), prepared by an in vitro transcription (IVT) system and encapsulated with lipid nanoparticles (LNP), was intramuscularly administered to non-obese diabetic (NOD) and cyclophosphamide (Cy)-NOD mice respectively. The results showed that the mRNA vaccines significantly reduced the incidence rate of type 1 diabetes, delayed the disease progression, improved glucose tolerance, and protected pancreatic morphology and function compared with the controls. Meanwhile, the vaccines also reduced the levels of autoantibodies to glutamic acid decarboxylase (GADA) and insulin (IAA) in the serum. Furthermore, the proportion of CD4+ T helper cell subsets was modulated in the spleen of mice treated with mRNA vaccines, in correspondence with the increased levels of IL-10 and TGF-β in serum, suggesting the possible mechanism of immune tolerance. This study provides experimental evidence for the application of mRNA vaccines encoding self-antigens in the prevention or treatment of type 1 diabetes.

Exosome-based immunotherapy as an innovative therapeutic approach in melanoma

The malignant form of melanoma is one of the deadliest human cancers that accounts for almost all of the skin tumor-related fatalities in its later stages. Achieving an exhaustive understanding of reliable cancer-specific markers and molecular pathways can provide numerous practical techniques and direct the way toward the development of rational curative medicines to increase the lifespan of patients. Immunotherapy has significantly enhanced the treatment of metastatic and late-stage melanoma, resulting in an incredible increase in positive responses to therapy. Despite the increasing occurrence of melanoma, the median survival rate for patients with advanced, inoperable terminal disease has increased from around six months to almost six years. The current knowledge of the tumor microenvironment (TME) and its interaction with the immune system has resulted in the swift growth of innovative immunotherapy treatments. Exosomes are small extracellular vesicles (EVs), ranging from 30 to 150 nm in size, that the majority of cells released them. Exosomes possess natural advantages such as high compatibility with living organisms and low potential for causing immune reactions, making them practical for delivering therapeutic agents like chemotherapy drugs, nucleic acids, and proteins. This review highlights recent advancements in using exosomes as an approach to providing medications for the treatment of melanoma.

Assessment of the herpes zoster risk among renal transplant recipients administered the influenza vaccine

BACKGROUND

Reactivation of the latent varicella-zoster virus can cause herpes zoster (HZ) infection, and renal transplant recipients undergoing immunosuppressive therapy are particularly susceptible to this condition. This study aims to evaluate the potential increase in HZ incidence following influenza vaccination among this specific patient population.

METHODS

This study was a population-based, retrospective, self-controlled case series. Data were retrieved from Taiwan's National Health Insurance Research Database spanning the years 2008 to 2017. Patients diagnosed with HZ within a 6-month period before and after receiving the influenza vaccine were eligible for inclusion. Two distinct time intervals were defined for analysis: the initial 15 days and 30 days following vaccination were categorized as risk intervals, while all other periods served as control intervals. Incidence rate ratios (IRRs) were computed to compare HZ incidence during the risk intervals with that during the control intervals.

RESULTS

This study encompassed a cohort of 4,222 renal transplant recipients who had received the influenza vaccine. Among this group, 67 recipients were subsequently diagnosed with HZ. The IRR during both the initial 15 days (IRR = 0.63; 95 % CI, 0.23-1.89) and the first 30 days (IRR = 1.50; 95 % CI, 0.71-3.16) following influenza vaccination did not demonstrate a statistically significant increase when compared to the post-exposure observation times. Comparable results were also observed when comparing these IRR values to the pre-exposure observation times. The subgroup analysis, stratified by age, sex, and underlying medical conditions (including cancer and autoimmune diseases), revealed that the IRRs did not exhibit statistically significant differences.

CONCLUSIONS

No significant association between the influenza vaccine and an elevated risk of HZ was detected. The administration of annual influenza vaccines appears to be a reasonable practice for renal transplant recipients.

Multiple tail ionizable lipids improve in vivo mRNA delivery efficiency with biosafety

Ionizable lipid-based lipid nanoparticles (LNP) play a crucial role in the delivery of mRNA. The hydrophobic tail of ionizable lipid affects the formation of LNP and the release of mRNA. In this report, we focus on the effect of the number, chain length, and double bond number of the hydrophobic tail on the delivery efficiency. First, a series of ionizable lipids with two, three and four tails were synthesized and characterized featured with imidazole group as the head. The ionizable lipids derived LNP were prepared using a microfluidic co-mixing device, yielding particles primarily in the size range of 100 to 150 nm, with a polydispersity index (PDI) below 0.2. Screening identified ionizable lipids with four tails exhibiting superior delivery efficiency, of which U-15, U-17, U-18 and U-19 demonstrated the highest performance. Additionally, the U-19 significantly prolongs mRNA expression duration, and along with specific extrahepatic delivery effect compared to ALC-0315. Tissue slice tests on representatives (U-06: two tails, U-19: four tails, U-29: three tails) revealed no notable abnormalities. Analysis of immunogenicity, liver and kidney function tests indicated that all samples exhibited no evident immunogenicity or in vivo toxicity. Findings from tests on lysosome escape, cell transfection, and cytotoxicity revealed excellent in vitro delivery effectiveness. In summary, among the 35 imidazole-based ionizable lipids screened, optimal effects were exhibited by four tails, which providing a new strategy for the development of ionizable lipids.

Advanced technologies for the development of infectious disease vaccines

Vaccines play a critical role in the prevention of life-threatening infectious disease. However, the development of effective vaccines against many immune-evading pathogens such as HIV has proven challenging, and existing vaccines against some diseases such as tuberculosis and malaria have limited efficacy. The historically slow rate of vaccine development and limited pan-variant immune responses also limit existing vaccine utility against rapidly emerging and mutating pathogens such as influenza and SARS-CoV-2. Additionally, reactogenic effects can contribute to vaccine hesitancy, further undermining the ability of vaccination campaigns to generate herd immunity. These limitations are fuelling the development of novel vaccine technologies to more effectively combat infectious diseases. Towards this end, advances in vaccine delivery systems, adjuvants, antigens and other technologies are paving the way for the next generation of vaccines. This Review focuses on recent advances in synthetic vaccine systems and their associated challenges, highlighting innovation in the field of nano- and nucleic acid-based vaccines.

Updated ASM Curriculum Guidelines describe core microbiology content to modernize the framework for microbiology education

Curricular guidelines promote standardized approaches to coverage of essential knowledge and skills in undergraduate education. The American Society for Microbiology (ASM) Curriculum Guidelines for Undergraduate Microbiology were developed in 2012. Continuous, rapid growth of knowledge in science and a dynamic, changing world necessitate updates to these guidelines. As such, ASM formed a task force in the summer of 2022. The task force assessed the 2012 ASM Curriculum Guidelines considering advancements in technology, an understanding of an expanded role of microbes, and a broader scope addressing relevant social and environmental aspects of microbiology. Language in the updated guidelines was also modified to better include eukaryotic microbes, viruses, and other acellular microbes. The task force formed working groups, each aimed at revising specific sections of the 2012 ASM Curriculum Guidelines. The revisions to the ASM Curriculum Guidelines were reviewed by subject matter experts and education stakeholders. Feedback from this peer review was incorporated into the updated guidelines, and further comments were solicited from the ASM Conference of Undergraduate Educators (ASMCUE) attendees in November 2023 before these guidelines were finalized. In this article, we describe the rationale and development of updated ASM Curriculum Guidelines which identify foundational concepts that will serve to improve microbial literacy and that can be expanded upon to address more advanced and specialized topics.

Simple Enzymatic Incorporation of 2'OMeU Nucleotide at the End of the Poly-A Tail for Enhancement of the mRNA Stability and Protein Expression

This study focused on the efficient post-transcriptional incorporation of a modified nucleoside at the end of the poly-A tail of mRNA. The modified mRNA was obtained in high yield and served to enhance protein expression. Utilizing poly-U polymerase, our method successfully enabled a single 2'OMeU residue to be incorporated into mRNA, which unexpectedly provided significant stabilization, even with only a single incorporation, to enhance the resistance of mRNA to degradation by cellular exonuclease. This stabilization effect allowed the mRNA to remain viable within the cell for an extended period to ultimately increase the translation efficiency at least 3-fold. This approach to mRNA modification at the 3' end with a single 2'OMeU residue, by utilizing a straightforward tailing method, surpasses other ligation methods in terms of mRNA modification efficiency. Collectively, our results highlight the potential of this method to significantly advance the development of highly effective mRNA-based therapies in the future.

Ionizable Cationic Lipids and Helper Lipids Synergistically Contribute to RNA Packing and Protection in Lipid-Based Nanomaterials

Lipid-based nanomaterials are used as a common delivery vehicle for RNA therapeutics. They typically include a formulation containing ionizable cationic lipids, cholesterol, phospholipids, and a small molar fraction of PEGylated lipids. The ionizable cationic lipids are considered a crucial element of the formulation for the way they mediate interactions with the anionic RNA as a function of pH. Here, we show, by means of molecular dynamics simulation of lipid formulations containing two different ionizable cationic lipids (DLinDMA and DLinDAP), that the direct interactions of those lipids with RNA, taken alone, may not be sufficient to determine the level of protection and packaging of mRNA. Our simulations help and highlight how the collective behavior of the lipids in the formulation, which determines the ability to envelop the RNA, and the level of hydration of the lipid-RNA interface may also play a significant role. This allows the drawing of a hypothesis about the experimentally observed differences in the transfection efficiency of the two ionizable cationic lipids.

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.

Impact of glycosylation on viral vaccines

Glycosylation is the most prominent modification important for vaccines and its specific pattern depends on several factors that need to be considered when developing a new biopharmaceutical. Tailor-made glycosylation can be exploited to develop more effective and safer vaccines; for this reason, a deep understanding of both glycoengineering strategies and glycans structures and functions is required. In this review we discuss the recent advances concerning glycoprotein expression systems and the explanation of glycans immunomodulation mechanisms. Furthermore, we highlight how glycans tune the immunological properties among different vaccines platforms (whole virus, recombinant protein, nucleic acid), also comparing commercially available formulations and describing the state-of-the-art analytical technologies for glycosylation analysis. The whole review stresses the aspect of glycoprotein glycans as a potential tool to overcome nowadays medical needs in vaccine field.

An Integrated Signaling Threshold Initiates IgG Response toward Virus-like Immunogens

Class-switched neutralizing Ab (nAb) production is rapidly induced upon many viral infections. However, due to the presence of multiple components in virions, the precise biochemical and biophysical signals from viral infections that initiate nAb responses remain inadequately defined. Using a reductionist system of synthetic virus-like structures, in this study, we show that a foreign protein on a virion-sized liposome can serve as a stand-alone danger signal to initiate class-switched nAb responses without T cell help or TLR but requires CD19. Introduction of internal nucleic acids (iNAs) obviates the need for CD19, lowers the epitope density (ED) required to elicit the Ab response, and transforms these structures into highly potent immunogens that rival conventional virus-like particles in their ability to elicit strong Ag-specific IgG. As early as day 5 after immunization, structures harboring iNAs and decorated with just a few molecules of surface Ag at doses as low as 100 ng induced all IgG subclasses of Ab in mice and reproduced the IgG2a/2c restriction that is long observed in live viral infections. These findings reveal a shared mechanism for the nAb response in mice. High ED is capable but not necessary for driving Ab secretion. Instead, even a few molecules of surface Ag, when combined with nucleic acids within these structures, can trigger strong IgG production. As a result, the signaling threshold for induction of IgG in individual B cells is set by dual signals originating from both ED on the surface and the presence of iNAs within viral particulate immunogens.

Using nucleolytic toxins as restriction enzymes enables new RNA applications

Over the past five decades, DNA restriction enzymes have revolutionized biotechnology. While these enzymes are widely used in DNA research and DNA engineering, the emerging field of RNA and mRNA therapeutics requires sequence-specific RNA endoribonucleases. Here, we describe EcoToxN1, a member of the type III toxin-antitoxin family of sequence-specific RNA endoribonucleases, and its use in RNA and mRNA analysis. This enzyme recognizes a specific pentamer in a single-stranded RNA and cleaves the RNA within this sequence. The enzyme is neither dependent on annealing of guide RNA or DNA oligos to the template nor does it require magnesium. Furthermore, it performs over a wide range of temperatures. With its unique functions and characteristics, EcoToxN1 can be classified as an RNA restriction enzyme. EcoToxN1 enables new workflows in RNA analysis and biomanufacturing, meeting the demand for faster, cheaper, and more robust analysis methods.

Accelerated Ten-Gram-Scale Synthesis of One-Component Multifunctional Sequence-Defined Ionizable Amphiphilic Janus Dendrimer 97

One-component multifunctional sequence-defined ionizable amphiphilic Janus dendrimers (IAJDs) were discovered in our laboratories in 2021 to represent a new class of synthetic vectors for the targeted delivery of messenger RNA (mRNA). They coassemble with mRNA by simple injection of their ethanol solution into a pH 4 acetate buffer containing the nucleic acid into monodisperse dendrimersome nanoparticles (DNPs) with predictable dimensions. DNPs are competitive with 4-component lipid nanoparticles (LNPs), which are used in commercial COVID-19 vaccines, except that IAJDs are prepared in fewer reaction steps than each individual component of the LNPs. This simple methodology for the synthesis of IAJDs and their coassembly with mRNA into DNPs, together with the precise placement of their individual components and indefinite stability at room temperature in air, make them attractive candidates for the development of nanomedicine-based targeted mRNA delivery. Access to the large-scale synthesis of IAJDs without the need for sophisticated technologies, instrumentation, and synthetic skills is expected to open numerous new opportunities worldwide in nanomedicine. The goal of this publication is to report an accelerated ten-gram-scale synthesis of IAJD97 from inexpensive food additives obtained from renewable plant phenolic acid starting materials by methodologies accessible to any laboratory. This accelerated synthesis can be accomplished in 4 days. We expect that the work reported here will impact the field of nanomedicine in both developed and less developed countries.

Modelling the Relative Vaccine Efficacy of ARCT-154, a Self-Amplifying mRNA COVID-19 Vaccine, versus BNT162b2 Using Immunogenicity Data

Background: Self-amplifying mRNA vaccines have the potential to increase the magnitude and duration of protection against COVID-19 by boosting neutralizing antibody titers and cellular responses. Methods: In this study, we used the immunogenicity data from a phase 3 randomized trial comparing the immunogenicity of ARCT-154, a self-amplifying mRNA COVID-19 vaccine, with BNT162b2 mRNA COVID-19 vaccine to estimate the relative vaccine efficacy (rVE) of the two vaccines over time in younger (<60 years) and older (≥60 years) adults. Results: By day 181 post-vaccination, the rVE against symptomatic and severe Wuhan-Hu-1 disease was 9.2-11.0% and 1.2-1.5%, respectively, across age groups whereas the rVE against symptomatic and severe Omicron BA.4/5 disease was 26.8-48.0% and 5.2-9.3%, respectively, across age groups. Sensitivity analysis showed that varying the threshold titer for 50% protection against severe disease up to 10% of convalescent sera revealed incremental benefits of ARCT-154 over BNT162b2, with an rVE of up to 28.0% against Omicron BA.4/5 in adults aged ≥60 year. Conclusions: Overall, the results of this study indicate that ARCT-154 elicits broader and more durable immunogenicity against SARS-CoV-2, translating to enhanced disease protection, particularly for older adults against Omicron BA.4/5.

Immunosenescence: How Aging Increases Susceptibility to Bacterial Infections and Virulence Factors

The process of aging leads to a progressive decline in the immune system function, known as immunosenescence, which compromises both innate and adaptive responses. This includes impairments in phagocytosis and decreased production, activation, and function of T- and B-lymphocytes, among other effects. Bacteria exploit immunosenescence by using various virulence factors to evade the host's defenses, leading to severe and often life-threatening infections. This manuscript explores the complex relationship between immunosenescence and bacterial virulence, focusing on the underlying mechanisms that increase vulnerability to bacterial infections in the elderly. Additionally, it discusses how machine learning methods can provide accurate modeling of interactions between the weakened immune system and bacterial virulence mechanisms, guiding the development of personalized interventions. The development of vaccines, novel antibiotics, and antivirulence therapies for multidrug-resistant bacteria, as well as the investigation of potential immune-boosting therapies, are promising strategies in this field. Future research should focus on how machine learning approaches can be integrated with immunological, microbiological, and clinical data to develop personalized interventions that improve outcomes for bacterial infections in the growing elderly population.

Vaccine skepticism and vaccine development stages; inoculation from "cowpox" lesion to the current mRNA vaccine of COVID-19: review

Global pandemics can be tackled by two means: lockdowns and vaccinations. As vaccination has a low impact on economic outcomes and better acceptance by people, it is the preferred method by most governments as a medium- to long-term solution. Vaccines have played a significant role in reducing the global burden of infectious diseases. They are designed to teach the immune system how to fight a particular infection before it causes a disease in subsequent exposures by creating a memory. Although vaccines effectiveness is well known, anti-vaccination movements pose significant challenges, even in high-income settings, leading to outbreaks of life-threatening infectious diseases. Hesitancy to take vaccines is not new and began with the first vaccination of smallpox. At that time, the problem was solved by a regulatory obligation to take vaccines, declared in England and Wales in 1853, which eventually led to its eradication in 1980. Different studies show that there is a decline in awareness of vaccines, hesitancy to take them, and concerns and trust issues regarding healthcare professionals. These problems have been rising over the past few decades for several reasons, notably, because of misinformation spread by social media. Therefore, the objective of this review is to provide a brief overview about vaccine hesitancy and attributable factors, illustrate the different types of vaccines, show the major challenges of vaccine development, and illustrate the pros and cons of each type.

Focused Ultrasound in Cancer Immunotherapy: A Review of Mechanisms and Applications

Ultrasound is well-perceived for its diagnostic application. Meanwhile, ultrasound, especially focused ultrasound (FUS), has also demonstrated therapeutic capabilities, such as thermal tissue ablation, hyperthermia, and mechanical tissue ablation, making it a viable therapeutic approach for cancer treatment. Cancer immunotherapy is an emerging cancer treatment approach that boosts the immune system to fight cancer, and it has also exhibited enhanced effectiveness in treating previously considered untreatable conditions. Currently, cancer immunotherapy is regarded as one of the four pillars of cancer treatment because it has fewer adverse effects than radiation and chemotherapy. In recent years, the unique capabilities of FUS in ablating tumors, regulating the immune system, and enhancing anti-tumor responses have resulted in a new field of research known as FUS-induced/assisted cancer immunotherapy. In this work, we provide a comprehensive overview of this new research field by introducing the basics of focused ultrasound and cancer immunotherapy and providing the state-of-the-art applications of FUS in cancer immunotherapy: the mechanisms and preclinical and clinical studies. This review aims to offer the scientific community a reliable reference to the exciting field of FUS-induced/assisted cancer immunotherapy, hoping to foster the further development of related technology and expand its medical applications.

Advances and applications of RNA vaccines in tumor treatment

Compared to other types of tumor vaccines, RNA vaccines have emerged as promising alternatives to conventional vaccine therapy due to their high efficiency, rapid development capability, and potential for low-cost manufacturing and safe drug delivery. RNA vaccines mainly include mRNA, circular RNA (circRNA), and Self-amplifying mRNA(SAM). Different RNA vaccine platforms for different tumors have shown encouraging results in animal and human models. This review comprehensively describes the advances and applications of RNA vaccines in antitumor therapy. Future directions for extending this promising vaccine platform to a wide range of therapeutic uses are also discussed.

Recent Advances in Lipid Nanoparticles and Their Safety Concerns for mRNA Delivery

INTRODUCTION

The advent of lipid nanoparticles (LNPs) as a delivery platform for mRNA therapeutics has revolutionized the biomedical field, particularly in treating infectious diseases, cancer, genetic disorders, and metabolic diseases. Recent Advances in Therapeutic LNPs: LNPs, composed of ionizable lipids, phospholipids, cholesterol, and polyethylene glycol (PEG) lipids, facilitate efficient cellular uptake and cytosolic release of mRNA while mitigating degradation by nucleases. However, as synthetic entities, LNPs face challenges that alter their therapeutic efficacy and safety concerns. Toxicity/Reactogenicity/Immunogenicity: This review provides a comprehensive overview of the latest advancements in LNP research, focusing on preclinical safety assessments encompassing toxicity, reactogenicity, and immunogenicity. Summary and Outlook: Additionally, it outlines potential strategies for addressing these challenges and offers insights into future research directions for enhancing the application of LNPs in mRNA therapeutics.

Construction and Immunogenicity of a Recombinant Porcine Pseudorabies Virus (PRV) Expressing the Major Neutralizing Epitope Regions of S1 Protein of Variant PEDV

Porcine epidemic diarrhea virus (PEDV) infection causes severe diarrhea and high mortality in neonatal piglets. Pseudorabies causes acute and often fatal infections in young piglets, respiratory disorders in growing pigs, and reproductive failure in sows. In late 2011, pseudorabies virus (PRV) variants occurred in Bartha-K61-vaccine-immunized swine herds, resulting in economic losses to the global pig industry. Therefore, it is essential to develop a safe and effective vaccine against both PEDV and PRV infections. In this study, we constructed a recombinant virus rPRV-PEDV S1 expressing the major neutralizing epitope region (COE, SS2, and SS6) of the PEDV S1 protein by homologous recombination technology and CRISPR/Cas9 gene editing technology, and then evaluated its biological characteristics in vitro and immunogenicity in pigs. The recombinant virus rPRV-PEDV S1 had similar growth kinetics in vitro to the parental rPRV NY-gE-/gI-/TK- strain, and was proven genetically stable in swine testicle (ST) cells and safe for piglets. PEDV S1-specific antibodies were detected in piglets immunized with rPRV-PEDV S1 on the 7th day post-immunization (dpi), and the antibody level increased rapidly at 14-21 dpi. Moreover, the immunized piglets receiving the recombinant virus exhibited alleviated clinical signs and reduced viral load compared to the unvaccinated group following a virulent PEDV HN2021 strain challenge. Also, piglets immunized with rPRV-PEDV S1 developed a PRV-specific humoral immune response and elicited complete protection against a lethal PRV NY challenge. These data indicate that the recombinant rPRV-PEDV S1 is a promising vaccine candidate strain for the prevention and control of PEDV and PRV infections.

Personalized mRNA vaccines in glioblastoma therapy: from rational design to clinical trials

Glioblastomas (GBMs) are the most common and aggressive malignant brain tumors, presenting significant challenges for treatment due to their invasive nature and localization in critical brain regions. Standard treatment includes surgical resection followed by radiation and adjuvant chemotherapy with temozolomide (TMZ). Recent advances in immunotherapy, including the use of mRNA vaccines, offer promising alternatives. This review focuses on the emerging use of mRNA vaccines for GBM treatment. We summarize recent advancements, evaluate current obstacles, and discuss notable successes in this field. Our analysis highlights that while mRNA vaccines have shown potential, their use in GBM treatment is still experimental. Ongoing research and clinical trials are essential to fully understand their therapeutic potential. Future developments in mRNA vaccine technology and insights into GBM-specific immune responses may lead to more targeted and effective treatments. Despite the promise, further research is crucial to validate and optimize the effectiveness of mRNA vaccines in combating GBM.

Evolving understanding of autoimmune mechanisms and new therapeutic strategies of autoimmune disorders

Autoimmune disorders are characterized by aberrant T cell and B cell reactivity to the body's own components, resulting in tissue destruction and organ dysfunction. Autoimmune diseases affect a wide range of people in many parts of the world and have become one of the major concerns in public health. In recent years, there have been substantial progress in our understanding of the epidemiology, risk factors, pathogenesis and mechanisms of autoimmune diseases. Current approved therapeutic interventions for autoimmune diseases are mainly non-specific immunomodulators and may cause broad immunosuppression that leads to serious adverse effects. To overcome the limitations of immunosuppressive drugs in treating autoimmune diseases, precise and target-specific strategies are urgently needed. To date, significant advances have been made in our understanding of the mechanisms of immune tolerance, offering a new avenue for developing antigen-specific immunotherapies for autoimmune diseases. These antigen-specific approaches have shown great potential in various preclinical animal models and recently been evaluated in clinical trials. This review describes the common epidemiology, clinical manifestation and mechanisms of autoimmune diseases, with a focus on typical autoimmune diseases including multiple sclerosis, type 1 diabetes, rheumatoid arthritis, systemic lupus erythematosus, and sjögren's syndrome. We discuss the current therapeutics developed in this field, highlight the recent advances in the use of nanomaterials and mRNA vaccine techniques to induce antigen-specific immune tolerance.

Oligonucleotide-Linked Lipid Nanoparticles as a Versatile mRNA Nanovaccine Platform

An effective delivery platform is crucial for the development of mRNA vaccines and therapeutics. Here, a versatile platform utilizing cholesterol-modified oligonucleotides (L-oligo) that bind to the mRNA within lipid nanoparticles (LNP), and enables the effective delivery of the mRNA into target cells is introduced. mRNA incorporated into LNPs via linkage with L-oligo, termed oligonucleotide-linked LNP (lnLNP), is superior in cellular uptake and transfection efficiency in target cells in vitro and in vivo, compared to the conventional LNP formulations. It is further applied lnLNP as an mRNA vaccine platform for SARS-CoV-2, demonstrating robust induction of neutralizing activity as well as polyfunctional SARS-CoV-2-specific T-cell response in vivo. The current strategy can be versatilely applied to different LNP platforms, for vaccine and therapeutic applications against various diseases, such as infections and cancers.

Recent advances in the influenza virus vaccine landscape: a comprehensive overview of technologies and trials

SUMMARYIn the United Kingdom (UK) in 2022/23, influenza virus infections returned to the levels recorded before the COVID-19 pandemic, exerting a substantial burden on an already stretched National Health Service (NHS) through increased primary and emergency care visits and subsequent hospitalizations. Population groups ≤4 years and ≥65 years of age, and those with underlying health conditions, are at the greatest risk of influenza-related hospitalization. Recent advances in influenza virus vaccine technologies may help to mitigate this burden. This review aims to summarize advances in the influenza virus vaccine landscape by describing the different technologies that are currently in use in the UK and more widely. The review also describes vaccine technologies that are under development, including mRNA, and universal influenza virus vaccines which aim to provide broader or increased protection. This is an exciting and important era for influenza virus vaccinations, and advances are critical to protect against a disease that still exerts a substantial burden across all populations and disproportionately impacts the most vulnerable, despite it being over 80 years since the first influenza virus vaccines were deployed.

Comparison of protection against mpox following mRNA or modified vaccinia Ankara vaccination in nonhuman primates

In 2022, mpox virus (MPXV) spread worldwide, causing 99,581 mpox cases in 121 countries. Modified vaccinia Ankara (MVA) vaccine use reduced disease in at-risk populations but failed to deliver complete protection. Lag in manufacturing and distribution of MVA resulted in additional MPXV spread, with 12,000 reported cases in 2023 and an additional outbreak in Central Africa of clade I virus. These outbreaks highlight the threat of zoonotic spillover by Orthopoxviruses. mRNA-1769, an mRNA-lipid nanoparticle (LNP) vaccine expressing MPXV surface proteins, was tested in a lethal MPXV primate model. Similar to MVA, mRNA-1769 conferred protection against challenge and further mitigated symptoms and disease duration. Antibody profiling revealed a collaborative role between neutralizing and Fc-functional extracellular virion (EV)-specific antibodies in viral restriction and ospinophagocytic and cytotoxic antibody functions in protection against lesions. mRNA-1769 enhanced viral control and disease attenuation compared with MVA, highlighting the potential for mRNA vaccines to mitigate future pandemic threats.

Immunotherapy for pediatric low-grade gliomas

Pediatric low-grade gliomas (pLGGs) are the most common brain tumor types affecting children. Although gross-total resection remains the treatment of choice, many tumors are not amenable to complete removal, because they either involve midline structures, such as the optic chiasm or hypothalamus, and are not conducive to aggressive resection, or have diffuse biological features and blend with the surrounding brain. Historically, radiation therapy was used as the second-line option for disease control, but with the recognition that this often led to adverse long-term sequelae, particularly in young children, conventional chemotherapy assumed a greater role in initial therapy for unresectable tumors. A variety of agents demonstrated activity, but long-term disease control was suboptimal, with more than 50% of tumors exhibiting disease progression within 5 years. More recently, it has been recognized that a high percentage of these tumors in children exhibit constitutive activation of the mitogen-activated protein kinase (MAPK) pathway because of BRAF translocations or mutations, NFI mutations, or a host of other anomalies that converged on MAPK. This led to phase 1, 2, and 3 trials that explored the activity of blocking this signaling pathway, and the efficacy of this approach compared to conventional chemotherapy. Despite initial promise of these strategies, not all children tolerate this therapy, and many tumors resume growth once MAPK inhibition is stopped, raising concern that long-term and potentially life-long treatment will be required to maintain tumor control, even among responders. This observation has led to interest in other treatments, such as immunotherapy, that may delay or avoid the need for additional treatments. This chapter will summarize the place of immunotherapy in the current armamentarium for these tumors and discuss prior results and future options to improve disease control, with a focus on our prior efforts and experience in this field.

Revisiting the dimensions of universal vaccine with special focus on COVID-19: Efficacy versus methods of designing

Even though the use of SARS-CoV-2 vaccines during the COVID-19 pandemic showed unprecedented success in a short time, it also exposed a flaw in the current vaccine design strategy to offer broad protection against emerging variants of concern. However, developing broad-spectrum vaccines is still a challenge for immunologists. The development of universal vaccines against emerging pathogens and their variants appears to be a practical solution to mitigate the economic and physical effects of the pandemic on society. Very few reports are available to explain the basic concept of universal vaccine design and development. This review provides an overview of the innate and adaptive immune responses generated against vaccination and essential insight into immune mechanisms helpful in designing universal vaccines targeting influenza viruses and coronaviruses. In addition, the characteristics, safety, and factors affecting the efficacy of universal vaccines have been discussed. Furthermore, several advancements in methods worthy of designing universal vaccines are described, including chimeric immunogens, heterologous prime-boost vaccines, reverse vaccinology, structure-based antigen design, pan-reactive antibody vaccines, conserved neutralizing epitope-based vaccines, mosaic nanoparticle-based vaccines, etc. In addition to the several advantages, significant potential constraints, such as defocusing the immune response and subdominance, are also discussed.

Lipid nanoparticles-based RNA therapies for breast cancer treatment

Breast cancer (BC) prevails as a major burden on global healthcare, being the most prevalent form of cancer among women. BC is a complex and heterogeneous disease, and current therapies, such as chemotherapy and radiotherapy, frequently fall short in providing effective solutions. These treatments fail to mitigate the risk of cancer recurrence and cause severe side effects that, in turn, compromise therapeutic responses in patients. Over the last decade, several strategies have been proposed to overcome these limitations. Among them, RNA-based technologies have demonstrated their potential across various clinical applications, notably in cancer therapy. However, RNA therapies are still limited by a series of critical issues like off-target effect and poor stability in circulation. Thus, novel approaches have been investigated to improve the targeting and bioavailability of RNA-based formulations to achieve an appropriate therapeutic outcome. Lipid nanoparticles (LNPs) have been largely proven to be an advantageous carrier for nucleic acids and RNA. This perspective explores the most recent advances on RNA-based technology with an emphasis on LNPs' utilization as effective nanocarriers in BC therapy and most recent progresses in their clinical applications.

The interaction of innate immune and adaptive immune system

The innate immune system serves as the body's first line of defense, utilizing pattern recognition receptors like Toll-like receptors to detect pathogens and initiate rapid response mechanisms. Following this initial response, adaptive immunity provides highly specific and sustained killing of pathogens via B cells, T cells, and antibodies. Traditionally, it has been assumed that innate immunity activates adaptive immunity; however, recent studies have revealed more complex interactions. This review provides a detailed dissection of the composition and function of the innate and adaptive immune systems, emphasizing their synergistic roles in physiological and pathological contexts, providing new insights into the link between these two forms of immunity. Precise regulation of both immune systems at the same time is more beneficial in the fight against immune-related diseases, for example, the cGAS-STING pathway has been found to play an important role in infections and cancers. In addition, this paper summarizes the challenges and future directions in the field of immunity, including the latest single-cell sequencing technologies, CAR-T cell therapy, and immune checkpoint inhibitors. By summarizing these developments, this review aims to enhance our understanding of the complexity interactions between innate and adaptive immunity and provides new perspectives in understanding the immune system.

NeoDesign: a computational tool for optimal selection of polyvalent neoantigen combinations

MOTIVATION

Tumor polyvalent neoantigen mRNA vaccines are gaining prominence in immunotherapy. The design of sequences in vaccine development is crucial for enhancing both the immunogenicity and safety of vaccines. However, a major challenge lies in selecting the optimal sequences from the large pools generated by multiple peptide combinations and synonymous codons.

RESULTS

We introduce NeoDesign, a computational tool designed to tackle the challenge of sequence design. NeoDesign comprises four modules: Library Construction, Optimal Path Filtering, Linker Addition, and λ-Evaluation. It aims to identify the optimal protein sequence for tumor polyvalent neoantigen vaccines by minimizing linker usage, avoiding unexpected neoantigens and functional domains, and simplifying the structure. It also provides a preference scheme to balance mRNA stability and protein expression when designing mRNA sequences for the optimal protein sequence. This tool can potentially improve the sequence design of tumor polyvalent neoantigen mRNA vaccines, thereby significantly advancing immunotherapy strategies.

AVAILABILITY AND IMPLEMENTATION

NeoDesign is freely available on https://github.com/HuangLab-Fudan/neoDesign and https://figshare.com/projects/NeoDesign/221704.

Delivery approaches of immunomodulatory nucleic acids for cancer therapy

Messenger RNA (mRNA) vaccines have made remarkable public health contributions during the pandemic and initiated a new era for nucleic acid-based therapeutics. With the unique strength of nucleic acids, including not only mRNA but also DNA, microRNA, small interfering RNA (siRNA), and other nucleic acids, either in tuning off genes or introducing function, nucleic acid therapeutics have been regarded as potential candidates for the treatment of many different diseases, especially for the immunomodulation in cancer. However, the scope of the applications was limited by the challenges in delivery due to intrinsic properties of nucleic acids including low stability, immunogenicity, and toxicity. Bioengineering approaches toward efficient and targeted delivery of therapeutic nucleic acids have gained momentum in clinical applications in the past few decades. Recent advances in the biotechnological approaches for the delivery of mRNA, siRNA, and clustered regularly interspaced short palindromic repeats (CRISPR)/Cas for immunomodulatory are promising alternatives in designing future cancer immunotherapy.

Combinatorial design of siloxane-incorporated lipid nanoparticles augments intracellular processing for tissue-specific mRNA therapeutic delivery

Systemic delivery of messenger RNA (mRNA) for tissue-specific targeting using lipid nanoparticles (LNPs) holds great therapeutic potential. Nevertheless, how the structural characteristics of ionizable lipids (lipidoids) impact their capability to target cells and organs remains unclear. Here we engineered a class of siloxane-based ionizable lipids with varying structures and formulated siloxane-incorporated LNPs (SiLNPs) to control in vivo mRNA delivery to the liver, lung and spleen in mice. The siloxane moieties enhance cellular internalization of mRNA-LNPs and improve their endosomal escape capacity, augmenting their mRNA delivery efficacy. Using organ-specific SiLNPs to deliver gene editing machinery, we achieve robust gene knockout in the liver of wild-type mice and in the lungs of both transgenic GFP and Lewis lung carcinoma (LLC) tumour-bearing mice. Moreover, we showed effective recovery from viral infection-induced lung damage by delivering angiogenic factors with lung-targeted Si5-N14 LNPs. We envision that our SiLNPs will aid in the clinical translation of mRNA therapeutics for next-generation tissue-specific protein replacement therapies, regenerative medicine and gene editing.