A comprehensive comparison of DNA and RNA vaccines.

Nucleic acid technology has revolutionized vaccine development, enabling rapid design and production of RNA and DNA vaccines for prevention and treatment of diseases. The successful deployment of mRNA and plasmid DNA vaccines against COVID-19 has further validated the technology. At present, mRNA platform is prevailing due to its higher efficacy, while DNA platform is undergoing rapid evolution because it possesses unique advantages that can potentially overcome the problems associated with the mRNA platform. To help understand the recent performances of the two vaccine platforms and recognize their clinical potentials in the future, this review compares the advantages and drawbacks of mRNA and DNA vaccines that are currently known in the literature, in terms of development timeline, financial cost, ease of distribution, efficacy, safety, and regulatory approval of products. Additionally, the review discusses the ongoing clinical trials, strategies for improvement, and alternative designs of RNA and DNA platforms for vaccination.

Construction of Toxoplasma gondii SRS29C nucleic acid vaccine and comparative immunoprotective study of an SRS29C and SAG1 combination.

Toxoplasma gondii is an intracellular protozoan parasite that infects all nucleated cells except the red blood cells. Currently, nucleic acid vaccines are being widely investigated in Toxoplasma gondii control, and several nucleic acid vaccine candidate antigens have shown good protection in various studies. The aim of this study was to construct a nucleic acid vaccine with Toxoplasma gondii SRS29C as the target gene. We explored the nucleic acid vaccine with Toxoplasma surface protein SRS29C and the combined gene of SRS29C and SAG1 and evaluated its immunoprotective effect against Toxoplasma gondii. To amplify the gene fragment and clone it to the expression vector, the recombinant plasmid pEGFP-SRS29C was constructed by PCR. Eukaryotic cells were transfected with the plasmid, and the expression of the target protein was assessed using the Western blot method. The level of serum IgG was determined via ELISA, and the splenic lymphocyte proliferation ability was detected using the CCK-8 method. The percentages of CD4+ and CD8+ T cells were measured by flow cytometry. Mice were immunised three times with single-gene nucleic acid vaccine and combination vaccine. Splenic lymphocytokine expression was determined using ELISA kits. The mice's survival time was monitored and recorded during an in vivo insect assault experiment, and the vaccine's protective power was assessed. The outcomes showed that PCR-amplification of an SRS29C gene fragment was successful. The 4,733-bp vector fragment and the 1,119-bp target segment were both recognised by double digestion. Additionally, after transfection of the recombinant plasmid pEGFP-SRS29C, Western blot examination of the extracted protein revealed the presence of a target protein strip at 66 kDa. The test results demonstrated that the IgG content in the serum of the pEGFP-SRS29C group and the co-immunization group was significantly higher than that of the PBS group and the empty vector group. The IgG potency induced by the co-immunization group was higher than that of the pEGFP-SRS29C group and the pEGFP-SAG1 group, the number of splenic lymphocyte proliferation number was higher than that of the PBS group and the empty vector group. The CD4+/CD8+ T ratio was higher than that of the PBS group and the empty vector group. The expression of IFN-γ and TNF-α in the splenocytes of the pEGFP-SRS29C group and the combined immunisation group was significantly higher following antigen stimulation. In the worm attack experiments, mice in the PBS and empty vector groups perished within 9 days of the worm attack, whereas mice in the pEGFP-SRS29C group survived for 18 days, mice in the pEGFP-SAG1 group survived for 21 days, and mice in the co-immunization group survived for 24 days. This demonstrates that the constructed Toxoplasma gondii nucleic acid vaccine pEGFP-SRS29C and the combined gene vaccine can induce mice to develop certain humoral and cellular immune responses, and enhance their ability to resist Toxoplasma gondii infection.

An Overview of SARS-CoV-2 Etiopathogenesis and Recent Developments in COVID-19 Vaccines.

The Coronavirus disease-2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), has significantly impacted the health and socioeconomic status of humans worldwide. Pulmonary infection of SARS-CoV-2 results in exorbitant viral replication and associated onset of inflammatory cytokine storm and disease pathology in various internal organs. However, the etiopathogenesis of SARS-CoV-2 infection is not fully understood. Currently, there are no targeted therapies available to cure COVID-19, and most patients are treated empirically with anti-inflammatory and/or anti-viral drugs, based on the disease symptoms. Although several types of vaccines are currently implemented to control COVID-19 and prevent viral dissemination, the emergence of new variants of SARS-CoV-2 that can evade the vaccine-induced protective immunity poses challenges to current vaccination strategies and highlights the necessity to develop better and improved vaccines. In this review, we summarize the etiopathogenesis of SARS-CoV-2 and elaborately discuss various types of vaccines and vaccination strategies, focusing on those vaccines that are currently in use worldwide to combat COVID-19 or in various stages of clinical development to use in humans.

Regulatory circular RNAs in viral diseases: applications in diagnosis and therapy.

Circular RNA (circRNA) forms closed loops via back-splicing in precursor mRNA, resisting exonuclease degradation. In higher eukaryotes, protein-coding genes create circRNAs through exon back-splicing. Unlike mRNAs, circRNAs possess unique production and structural traits, bestowing distinct cellular functions and biomedical potential. In this review, we explore the pivotal roles of viral circRNAs and associated RNA in various biological processes. Analysing the interactions between viral circRNA and host cellular machinery yields fresh insights into antiviral immunity, catalysing the development of potential therapeutics. Furthermore, circRNAs serve as enduring biomarkers in viral diseases due to their stable translation within specific tissues. Additionally, a deeper understanding of translational circRNA could expedite the establishment of circRNA-based expression platforms, meeting the rising demand for broad-spectrum viral vaccines. We also highlight the applications of circular RNA in biomarker studies as well as circRNA-based therapeutics. Prospectively, we expect a technological revolution in combating viral infections using circRNA.

Transient inhibition of lysosomal functions potentiates nucleic acid vaccines.

Nucleic acid vaccines have shown promising results in the clinic against infectious diseases and cancers. To robustly improve the vaccine efficacy and safety, we developed an approach to increase the intracellular stability of nucleic acids by transiently inhibiting lysosomal function in targeted tissues using sucrose. To achieve efficient and localized delivery of sucrose in animals, we designed a biomimetic lipid nanoparticle (LNP) to target the delivery of sucrose into mouse muscle cells. Using this approach, viral antigen expression in mouse muscle after DNA vaccination was substantially increased and prolonged without inducing local or systemic inflammation or toxicity. The same change in antigen expression would be achieved if the vaccine dose could be increased by 3,000 folds, which is experimentally and clinically impractical due to material restrictions and severe toxicity that will be induced by such a high dose of nucleic acids. The increase in antigen expression augmented the infiltration and activation of antigen-presenting cells, significantly improved vaccine-elicited humoral and T cell responses, and fully protected mice against the viral challenge at a low dose of vaccine. Based on these observations, we conclude that transient inhibition of lysosome function in target tissue by sucrose LNPs is a safe and potent approach to substantially improve nucleic acid-based vaccines.

Progress and prospects on vaccine development against monkeypox infection.

The monkeypox virus (MPOX) is an uncommon zoonotic illness brought on by an orthopoxvirus (OPXV). MPOX can occur with symptoms similar to smallpox. Since April 25, 2023, 110 nations have reported 87,113 confirmed cases and 111 fatalities. Moreover, the outspread prevalence of MPOX in Africa and a current outbreak of MPOX in the U.S. have made it clear that naturally occurring zoonotic OPXV infections remain a public health concern. Existing vaccines, though they provide cross-protection to MPOX, are not specific for the causative virus, and their effectiveness in the light of the current multi-country outbreak is still to be verified. Furthermore, as a sequel of the eradication and cessation of smallpox vaccination for four decades, MPOX found a possibility to re-emerge, but with distinct characteristics. The World Health Organization (WHO) suggested that nations use affordable MPOX vaccines within a framework of coordinated clinical effectiveness and safety evaluations. Vaccines administered in the smallpox control program and conferred immunity against MPOX. Currently, vaccines approved by WHO for use against MPOX are replicating (ACAM2000), low replicating (LC16m8), and non-replicating (MVA-BN). Although vaccines are accessible, investigations have demonstrated that smallpox vaccination is approximately 85% efficient in inhibiting MPOX. In addition, developing new vaccine methods against MPOX can help prevent this infection. To recognize the most efficient vaccine, it is essential to assess effects, including reactogenicity, safety, cytotoxicity effect, and vaccine-associated side effects, especially for high-risk and vulnerable people. Recently, several orthopoxvirus vaccines have been produced and are being evaluated. Hence, this review aims to provide an overview of the efforts dedicated to several types of vaccine candidates with different strategies for MPOX, including inactivated, live-attenuated, virus-like particles (VLPs), recombinant protein, nucleic acid, and nanoparticle-based vaccines, which are being developed and launched.

Nucleic acid immunotherapeutics and vaccines: A promising approach to glioblastoma multiforme treatment.

Glioblastoma multiforme (GBM) is a deadly and difficult to treat primary brain tumor for which satisfactory therapeutics have yet to be discovered. While cancer immunotherapeutics, such as immune checkpoint inhibitors, have successfully improved the treatment of some other types of cancer, the poorly immunogenic GBM tumor cells and the immunosuppressive GBM tumor microenvironment have made it difficult to develop GBM immunotherapeutics. Nucleic acids therapeutics and vaccines, particularly those of mRNA, have become a popular field of research in recent years. This review presents the progress of nucleic acid therapeutics and vaccines for GBM and briefly covers some representative delivery methods of nucleic acids to the central nervous system (CNS) for GBM therapy.

SARS-CoV-2 Vaccines: Types, Working Principle, and Its Impact on Thrombosis and Gastrointestinal Disorders.

In the current scenario of the coronavirus pandemic caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), considerable efforts have been made to control the pandemic by the development of a strong immune system through massive vaccination. Just after the discovery of the genetic sequences of SARS-CoV-2, the development of vaccines became the prime focus of scientists around the globe. About 200 SARS-CoV-2 candidate vaccines have already been entered into preclinical and clinical trials. Various traditional and novel approaches are being utilized as a broad range of platforms. Viral vector (replicating and non-replicating), nucleic acid (DNA and RNA), recombinant protein, virus-like particle, peptide, live attenuated virus, an inactivated virus approaches are the prominent attributes of the vaccine development. This review article includes the current knowledge about the platforms used for the development of different vaccines, their working principles, their efficacy, and the impacts of COVID-19 vaccines on thrombosis. We provide a detailed description of the vaccines that are already approved by administrative authorities. Moreover, various strategies utilized in the development of emerging vaccines that are in the trial phases along with their mode of delivery have been discussed along with their effect on thrombosis and gastrointestinal disorders.

Perspectives from recent advances of Helicobacter pylori vaccines research.

BACKGROUND: Helicobacter pylori (H. pylori) infection is the main factor leading to some gastric diseases. Currently, H. pylori infection is primarily treated with antibiotics. However, with the widespread application of antibiotics, H. pylori resistance to antibiotics has also gradually increased year by year. Vaccines may be an alternative solution to clear H. pylori. AIMS: By reviewing the recent progress on H. pylori vaccines, we expected it to lead to more research efforts to accelerate breakthroughs in this field. MATERIALS & METHODS: We searched the research on H. pylori vaccine in recent years through PubMed®, and then classified and summarized these studies. RESULTS: The study of the pathogenic mechanism of H. pylori has led to the development of vaccines using some antigens, such as urease, catalase, and heat shock protein (Hsp). Based on these antigens, whole-cell, subunit, nucleic acid, vector, and H. pylori exosome vaccines have been tested. DISCUSSION: At present, researchers have developed many types of vaccines, such as whole cell vaccines, subunit vaccines, vector vaccines, etc. However, although some of these vaccines induced protective immunity in mouse models, only a few were able to move into human trials. We propose that mRNA vaccine may play an important role in preventing or treating H. pylori infection. The current study shows that we have developed various types of vaccines based on the virulence factors of H. pylori. However, only a few vaccines have entered human clinical trials. In order to improve the efficacy of vaccines, it is necessary to enhance T-cell immunity. CONCLUSION: We should fully understand the pathogenic mechanism of H. pylori and find its core antigen as a vaccine target.

Enhanced Muscle Fibers of Epinephelus coioides by Myostatin Autologous Nucleic Acid Vaccine.

Epinephelus coioides is a fish species with high economic value due to its delicious meat, high protein content, and rich fatty acid nutrition. It has become a high-economic fish in southern parts of China and some other Southeast Asian countries. In this study, the myostatin nucleic acid vaccine was constructed and used to immunize E. coioides. The results from body length and weight measurements indicated the myostatin nucleic acid vaccine promoted E. coioides growth performance by increasing muscle fiber size. The results from RT-qPCR analysis showed that myostatin nucleic acid vaccine upregulated the expression of myod, myog and p21 mRNA, downregulated the expression of smad3 and mrf4 mRNA. This preliminary study is the first report that explored the role of myostatin in E. coioides and showed positive effects of autologous nucleic acid vaccine on the muscle growth of E. coioides. Further experiments with increased numbers of animals and different doses are needed for its application to E. coiodes aquaculture production.

Advances in the polymeric delivery of nucleic acid vaccines.

Nucleic acid vaccines, especially messenger RNA (mRNA) vaccines, display unique benefits in the current COVID-19 pandemic. The application of polymeric materials as delivery carriers has greatly promoted nucleic acid vaccine as a promising prophylactic and therapeutic strategy. The inherent properties of polymeric materials render nucleic acid vaccines with excellent in vivo stability, enhanced biosafety, specific cellular uptake, endolysosomal escape, and promoted antigen expression. Although polymeric delivery of nucleic acid vaccines has progressed significantly in the past decades, clinical translation of polymer-gene vaccine systems still faces insurmountable challenges. This review summarizes the diverse polymers and their characterizations and representative formulations for nucleic acid vaccine delivery. We also discussed existing problems, coping strategies, and prospect relevant to applications of nucleic acid vaccines and polymeric carriers. This review highlights the rational design and development of polymeric vaccine delivery systems towards meeting the goals of defending serious or emerging diseases.

Polyclonal antibodies against potato spindle tuber viroid RNA.

Ribonucleic acid (RNA) can act as a hapten in the direct immunization of animals. For antigen synthesis, 65 mg of viroid RNA were obtained by in vitro transcription of the recombinant DNA. We received a reasonable immune response in mice and rabbits with synthesized conjugate viroid RNA-lysozyme. Analyses of polyclonal mouse and rabbit antisera as well as estimates of antibody specificity were performed by dot-Enzyme Linked Immunosorbent Assay (ELISA), sandwich ELISA, and northern immunoblotting. Antiserum obtained showed strong cross-reactions with cellular RNA. The viroid polyclonal antibody cross-reactions with cellular RNAs were depleted via titration antibodies by the plant cellular or commercial yeast RNA. We successfully used antibodies against the viroid RNA-lysozyme antigen to detect the wild-type potato viroid and diagnose potato viroid infection. We presume that intrinsic cross-reactions of RNA antibodies are potentially dangerous after nucleic acid vaccination. Research into the specificity of antibodies against viral RNAs is underway.

SARS-CoV-2-Specific Vaccine Candidates; the Contribution of Structural Vaccinology.

SARS-CoV-2 vaccine production has taken us by storm. We aim to fill in the history of concepts and the work of pioneers and provide a framework of strategies employing structural vaccinology. Cryo-electron microscopy became crucial in providing three-dimensional (3D) structures and creating candidates eliciting T and B cell-mediated immunity. It also determined structural changes in the emerging mutants in order to design new constructs that can be easily, quickly and safely added to the vaccines. The full-length spike (S) protein, the S1 subunit and its receptor binding domain (RBD) of the virus are the best candidates. The vaccine development to cease this COVID-19 pandemic sets a milestone for the pan-coronavirus vaccine's designing and manufacturing. By employing structural vaccinology, we propose that the mRNA and the protein sequences of the currently approved vaccines should be modified rapidly to keep up with the more infectious new variants.

Beyond Sequencing: Prioritizing and Delivering Neoantigens for Cancer Vaccines.

Neoantigens are tumor-specific proteins and peptides that can be highly immunogenic. Immune-mediated tumor rejection is strongly associated with cytotoxic responses to neoantigen-derived peptides in noncovalent association with self-HLA molecules. Neoantigen-based therapies, such as adoptive T cell transfer, have shown the potential to induce remission of treatment-resistant metastatic disease in select patients. Cancer vaccines are similarly designed to elicit or amplify antigen-specific T cell populations and stimulate directed antitumor immunity, but the selection and prioritization of the neoantigens remains a challenge. Bioinformatic algorithms can predict tumor neoantigens from somatic mutations, insertion-deletions, and other aberrant peptide products, but this often leads to hundreds of potential neoepitopes, all unique for that tumor. Selecting neoantigens for cancer vaccines is complicated by the technical challenges of neoepitope discovery, the diversity of HLA molecules, and intratumoral heterogeneity of passenger mutations leading to immune escape. Despite strong preclinical evidence, few neoantigen cancer vaccines tested in vivo have generated epitope-specific T cell populations, suggesting suboptimal immune system activation. In this chapter, we review factors affecting the prioritization and delivery of candidate neoantigens in the design of therapeutic and preventive cancer vaccines and consider synergism with standard chemotherapies.

Tick immunity using mRNA, DNA and protein-based Salp14 delivery strategies.

Guinea pigs exposed to multiple infestations with Ixodes scapularis ticks develop acquired resistance to ticks, which is also known as tick immunity. The I. scapularis salivary components that contribute to tick immunity are likely multifactorial. An anticoagulant that inhibits factor Xa, named Salp14, is present in tick saliva and is associated with partial tick immunity. A tick bite naturally releases tick saliva proteins into the vertebrate host for several days, which suggests that the mode of antigen delivery may influence the genesis of tick immunity. We therefore utilized Salp14 as a model antigen to examine tick immunity using mRNA lipid nanoparticles (LNPs), plasmid DNA, or recombinant protein platforms. salp14 containing mRNA-LNPs vaccination elicited erythema at the tick bite site after tick challenge that occurred earlier, and that was more pronounced, compared with DNA or protein immunizations. Humoral and cellular responses associated with tick immunity were directed towards a 25 amino acid region of Salp14 at the carboxy terminus of the protein, as determined by antibody responses and skin-testing assays. This study demonstrates that the model of antigen delivery, also known as the vaccine platform, can influence the genesis of tick immunity in guinea pigs. mRNA-LNPs may be useful in helping to elicit erythema at the tick bite site, one of the most important early hallmarks of acquired tick resistance. mRNA-LNPs containing tick genes is a useful platform for the development of vaccines that can potentially prevent selected tick-borne diseases.

Co-Delivery of mRNA and pDNA Using Thermally Stabilized Coacervate-Based Core-Shell Nanosystems.

Co-delivery of different species of protein-encoding polynucleotides, e.g., messenger RNA (mRNA) and plasmid DNA (pDNA), using the same nanocarrier is an interesting topic that remains scarcely researched in the field of nucleic acid delivery. The current study hence aims to explore the possibility of the simultaneous delivery of mRNA (mCherry) and pDNA (pAmCyan) using a single nanocarrier. The latter is based on gelatin type A, a biocompatible, and biodegradable biopolymer of broad pharmaceutical application. A core-shell nanostructure is designed with a thermally stabilized gelatin-pDNA coacervate in its center. Thermal stabilization enhances the core's colloidal stability and pDNA shielding effect against nucleases as confirmed by nanoparticle tracking analysis and gel electrophoresis, respectively. The stabilized, pDNA-loaded core is coated with the cationic peptide protamine sulfate to enable additional surface-loading with mRNA. The dual-loaded core-shell system transfects murine dendritic cell line DC2.4 with both fluorescent reporter mRNA and pDNA simultaneously, showing a transfection efficiency of 61.4 ± 21.6% for mRNA and 37.6 ± 19.45% for pDNA, 48 h post-treatment, whereas established commercial, experimental, and clinical transfection reagents fail. Hence, the unique co-transfectional capacity and the negligible cytotoxicity of the reported system may hold prospects for vaccination among other downstream applications.

Promising Technologies in the Field of Helminth Vaccines.

Helminths contribute a larger global burden of disease than both malaria and tuberculosis. These eukaryotes have caused human infections since before our earliest recorded history (i.e.: earlier than 1200 B.C. for Schistosoma spp.). Despite the prevalence and importance of these infections, helminths are considered a neglected tropical disease for which there are no vaccines approved for human use. Similar to other parasites, helminths are complex organisms which employ a plethora of features such as: complex life cycles, chronic infections, and antigenic mimicry to name a few, making them difficult to target by conventional vaccine strategies. With novel vaccine strategies such as viral vectors and genetic elements, numerous constructs are being defined for a wide range of helminth parasites; however, it has yet to be discussed which of these approaches may be the most effective. With human trials being conducted, and a pipeline of potential anti-helminthic antigens, greater understanding of helminth vaccine-induced immunity is necessary for the development of potent vaccine platforms and their optimal design. This review outlines the conventional and the most promising approaches in clinical and preclinical helminth vaccinology.

[Progress and analysis on the development of 2019-nCoV vaccine].

As the COVID-19 pandemic is intensifying globally, more and more people are pinning their hopes on the development of vaccines. At present, there are many research teams who have adopted different vaccine technology routes to develop 2019-nCoV vaccines. This article reviews and analyzes the current development and research status of 2019-nCoV vaccines in different routes, and explores their possible development in the future.

Progress and analysis on the development of 2019-nCoV vaccine / 生物医学工程学杂志

As the COVID-19 pandemic is intensifying globally, more and more people are pinning their hopes on the development of vaccines. At present, there are many research teams who have adopted different vaccine technology routes to develop 2019-nCoV vaccines. This article reviews and analyzes the current development and research status of 2019-nCoV vaccines in different routes, and explores their possible development in the future.

Nucleic Acid Vaccine Targeting Nogo-66 Receptor and Paired Immunoglobulin-Like Receptor B as an Immunotherapy Strategy for Spinal Cord Injury in Rats.

Nogo-66 receptor (NgR) and paired immunoglobulin-like receptor B (PirB) are two common receptors of various myelin-associated inhibitors (MAIs) and, thus, play an important role in MAIs-induced inhibitory signalling of regeneration following spinal cord injury (SCI). Based on the concept of protective autoimmunity, vaccine approaches could induce the production of antibodies against inhibitors in myelin, such as using purified myelin, spinal cord homogenates, or MAIs receptor NgR, in order to block the inhibitory effects and promote functional recovery in SCI models. However, due to the complication of the molecules and the mechanisms involved in MAIs-mediated inhibitory signalling, these immunotherapy strategies have yielded inconsistent outcomes. Therefore, we hypothesized that the choice and modification of self-antigens, and co-regulating multiple targets, may be more effective in repairing the injured spinal cord and improving functional recovery. In this study, NgR and PirB were selected to construct a double-targeted granulocyte-macrophage colony stimulating factor-NgR-PirB (GMCSF-NgR-PirB) nucleic acid vaccine, and investigate the efficacy of this immunotherapy in a spinal cord injury model in rats. The results showed that this vaccination could stimulate the production of antibodies against NgR and PirB, block the inhibitory effects mediated by various MAIs, and promote nerve regeneration and functional recovery after spinal cord injury. These findings suggest that nucleic acid vaccination against NgR and PirB can be a promising therapeutic strategy for SCI and other central nervous system diseases and injuries.