DNA vaccines: prime time is now

The Nuclear DNA Sensor IFI16 Indiscriminately Binds to and Diminishes Accessibility of the HSV-1 Genome to Suppress Infection

Human cells identify invading pathogens and activate immune signaling pathways through a wide array of pattern recognition receptors, including DNA sensors. The interferon-inducible protein 16 (IFI16) is a nuclear DNA sensor that recognizes double-stranded DNA from a number of viral sources, including genomes of nuclear-replicating viruses. Among these is the prevalent human pathogen herpes simplex virus 1 (HSV-1). Upon binding to the HSV-1 DNA genome, IFI16 both induces antiviral cytokine expression and suppresses virus gene expression. Here, we used a multiomics approach of DNA sequencing techniques paired with targeted mass spectrometry to obtain an extensive view of the interaction between IFI16 and the HSV-1 genome and how this binding affects the viral DNA structure and protein expression. Through chromatin immunoaffinity purification coupled with next-generation DNA sequencing (ChIP-seq), we found that IFI16 binds to the HSV-1 genome in a sequence-independent manner while simultaneously exhibiting broad enrichment at two loci: UL30, the viral DNA polymerase gene, and US1 to US7. The assay for transposase-accessible chromatin with sequencing (ATAC-seq) revealed that these two regions are among the most accessible stretches of DNA on the genome, thereby facilitating IFI16 binding. Accessibility of the entire HSV-1 genome is elevated upon IFI16 knockout, indicating that expression of IFI16 globally induces chromatinization of viral DNA. Deletion of IFI16 also results in a global increase in the expression of HSV-1 proteins, as measured by parallel reaction monitoring-mass spectrometry of viral proteins representing 80% of the HSV-1 genome. Altogether, we demonstrate that IFI16 interacts with the HSV-1 genome in a sequence-independent manner, coordinating epigenetic silencing of the viral genome and decreasing protein expression and virus replication. IMPORTANCE Mammalian host defense against viral infection includes broad-acting cellular restriction factors, as well as effectors of intrinsic and innate immunity. IFI16 is a critical nuclear host defense factor and intrinsic immune protein involved in binding viral DNA genomes, thereby repressing the replication of nucleus-replicating viruses, including the human herpes simplex virus 1. What has remained unclear is where on the viral genome IFI16 binds and how binding affects both viral DNA structural accessibility and viral protein expression. Our study provides a global view of where and how a nuclear restriction factor of DNA viruses associates with viral genomes to exert antiviral functions during early stages of an acute virus infection. Our study can additionally serve as a systems-level model to evaluate nuclear DNA sensor interactions with viral genomes, as well as the antiviral outcomes of transcriptionally silencing pathogen-derived DNA.

Why We Need Precision Vaccinology

Vaccine development has moved from an empirical origin to the use of antigenic characterization, structural biology, immune function definition, protein synthesis, and precise definition of immune correlates of protection in order to deal with more difficult biology of current targets.

Robust humoral immune response against rabies virus in rabbits and guinea pigs immunized with plasmid DNA vectors encoding rabies virus glycoproteins - An approach to the production of polyclonal antibody reagents

DNA-based immunization has been previously shown to be an efficient approach to induce robust immunity against infectious diseases in animals and humans. The advantages of DNA vaccines are simplicity of their construction and production, low cost, high stability, and ability to elicit a full spectrum of immune responses to target antigens. The goals of this study were (i) to assess the antibody immune response to rabies virus glycoproteins (rGPs) in rabbits and guinea pigs after intramuscular immunization with pTargeT and pVAC2-mcs mammalian expression vectors encoding either the wild-type (WT) or codon-optimized (cOPT) rGP genes; and (ii) to prepare in-house rabbit anti-rGP polyclonal antibody reagents suitable for in Single Radial Immunodiffusion (SRID) and Indirect Fluorescent Antibody (IFA) assays. The maximum antibody responses against rabies virus in rabbits and guinea pigs were observed after immunization series with 500 μg/dose of pVAC2-mcs vector encoding either the WT or cOPT rGP genes adjuvanted with Emulsigen-D. No significant difference in the anti-rabies virus neutralizing antibody titers was observed in rabbits immunized with the WT and cOPT rGPs. The in-house rabbit anti-rGP polyclonal antibody reagents reacted comparable to the current reference reagents in SRID and IFA assays. The results of the study demonstrated that the DNA immunization of animals with the WT or cOPT rGPs is a promising approach to either induction of high anti-rabies virus neutralizing antibody titers in vivo or for production of polyclonal antibody reagents against rabies.

Vaccination and immunotherapies in neuroimmunological diseases

Neuroimmunological diseases and their treatment compromise the immune system, thereby increasing the risk of infections and serious illness. Consequently, vaccinations to protect against infections are an important part of the clinical management of these diseases. However, the wide variety of immunotherapies that are currently used to treat neuroimmunological disease — particularly multiple sclerosis and neuromyelitis optica spectrum disorders — can also impair immunological responses to vaccinations. In this Review, we discuss what is known about the effects of various immunotherapies on immunological responses to vaccines and what these effects mean for the safe and effective use of vaccines in patients with a neuroimmunological disease. The success of vaccination in patients receiving immunotherapy largely depends on the specific mode of action of the immunotherapy. To minimize the risk of infection when using immunotherapy, assessment of immune status and exclusion of underlying chronic infections before initiation of therapy are essential. Selection of the required vaccinations and leaving appropriate time intervals between vaccination and administration of immunotherapy can help to safeguard patients. We also discuss the rapidly evolving knowledge of how immunotherapies affect responses to SARS-CoV-2 vaccines and how these effects should influence the management of patients on these therapies during the COVID-19 pandemic.

In this Review, the authors discuss how various immunotherapies for neuroimmunological diseases interact with vaccination responses, including responses to SARS-CoV-2 vaccinations, and the implications for the safe and effective use of vaccines in patients with these diseases.

Vaccination against infection is an essential part of the management of neuroimmunological diseases.

All indicated vaccinations should be administered before initiation of immunotherapy whenever possible; appropriate intervals between vaccination and treatment vary with treatment and vaccination.

Inactivated vaccines are considered safe in neuroimmunological diseases but live vaccines are generally contraindicated during immunotherapy.

Vaccination responses during immunotherapy can be diminished or abrogated, depending on the treatment and vaccination; antibody titre testing to monitor responses can be considered where appropriate.

Vaccinations must be avoided during relapses or exacerbations of neuroimmunological diseases.

Vaccination against SARS-CoV-2 is recommended for patients with neuroimmunological disease but some immunotherapies limit the immune response; therefore, timing should be considered carefully.

A global survey in the developmental landscape of possible vaccination strategies for COVID-19

The development of COVID-19 vaccines was promptly regulated to ensure the best possible approach. By January 2022, 75 candidates reached preclinical evaluation in various animal models, 114 vaccines were in clinical trials on humans, and 48 were in the final testing stages. Vaccine platforms range from whole virus vaccines to nucleic acid vaccines, which are the most promising in prompt availability and safety. The USA and Europe have approved vaccines developed by Pfizer-BioNTech (BNT162b2) and Moderna (mRNa1273). So far, Pfizer-BioNTech, Moderna, Johnson & Johnson, AstraZeneca-University of Oxford, Sinopharm, Sinovac Biotech Gamaleya, Bharat Biotech, and Novavax have documented effective vaccines. Even with technological advances and a fast-paced development approach, many limitations and problems need to be overcome before a large-scale production of new vaccines can start. The Key is to ensure equal and fair distribution globally through regulatory measures. Recent studies link Bacillus Calmette-Guérin (BCG) vaccination programs and lower disease severity.

Revisiting the role of pulsed electric fields in overcoming the barriers to in vivo gene electrotransfer

Gene therapies are revolutionizing medicine by providing a way to cure hitherto incurable diseases. The scientific and technological advances have enabled the first gene therapies to become clinically approved. In addition, with the ongoing COVID-19 pandemic, we are witnessing record speeds in the development and distribution of gene-based vaccines. For gene therapy to take effect, the therapeutic nucleic acids (RNA or DNA) need to overcome several barriers before they can execute their function of producing a protein or silencing a defective or overexpressing gene. This includes the barriers of the interstitium, the cell membrane, the cytoplasmic barriers and (in case of DNA) the nuclear envelope. Gene electrotransfer (GET), i.e., transfection by means of pulsed electric fields, is a non-viral technique that can overcome these barriers in a safe and effective manner. GET has reached the clinical stage of investigations where it is currently being evaluated for its therapeutic benefits across a wide variety of indications. In this review, we formalize our current understanding of GET from a biophysical perspective and critically discuss the mechanisms by which electric field can aid in overcoming the barriers. We also identify the gaps in knowledge that are hindering optimization of GET in vivo.

Identification of electroporation sites in the complex lipid organization of the plasma membrane

The plasma membrane of a biological cell is a complex assembly of lipids and membrane proteins, which tightly regulate transmembrane transport. When a cell is exposed to strong electric field, the membrane integrity becomes transiently disrupted by formation of transmembrane pores. This phenomenon termed electroporation is already utilized in many rapidly developing applications in medicine including gene therapy, cancer treatment, and treatment of cardiac arrhythmias. However, the molecular mechanisms of electroporation are not yet sufficiently well understood; in particular, it is unclear where exactly pores form in the complex organization of the plasma membrane. In this study, we combine coarse-grained molecular dynamics simulations, machine learning methods, and Bayesian survival analysis to identify how formation of pores depends on the local lipid organization. We show that pores do not form homogeneously across the membrane, but colocalize with domains that have specific features, the most important being high density of polyunsaturated lipids. We further show that knowing the lipid organization is sufficient to reliably predict poration sites with machine learning. Additionally, by analysing poration kinetics with Bayesian survival analysis we show that poration does not depend solely on local lipid arrangement, but also on membrane mechanical properties and the polarity of the electric field. Finally, we discuss how the combination of atomistic and coarse-grained molecular dynamics simulations, machine learning methods, and Bayesian survival analysis can guide the design of future experiments and help us to develop an accurate description of plasma membrane electroporation on the whole-cell level. Achieving this will allow us to shift the optimization of electroporation applications from blind trial-and-error approaches to mechanistic-driven design.

Induction of tier-2 neutralizing antibodies in mice with a DNA-encoded HIV envelope native like trimer

HIV Envelope (Env) is the main vaccine target for induction of neutralizing antibodies. Stabilizing Env into native-like trimer (NLT) conformations is required for recombinant protein immunogens to induce autologous neutralizing antibodies(nAbs) against difficult to neutralize HIV strains (tier-2) in rabbits and non-human primates. Immunizations of mice with NLTs have generally failed to induce tier-2 nAbs. Here, we show that DNA-encoded NLTs fold properly in vivo and induce autologous tier-2 nAbs in mice. DNA-encoded NLTs also uniquely induce both CD4 + and CD8 + T-cell responses as compared to corresponding protein immunizations. Murine neutralizing antibodies are identified with an advanced sequencing technology. The structure of an Env-Ab (C05) complex, as determined by cryo-EM, identifies a previously undescribed neutralizing Env C3/V5 epitope. Beyond potential functional immunity gains, DNA vaccines permit in vivo folding of structured antigens and provide significant cost and speed advantages for enabling rapid evaluation of new HIV vaccines.

Nucleic acid delivery of immune-focused SARS-CoV-2 nanoparticles drives rapid and potent immunogenicity capable of single-dose protection

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines may target epitopes that reduce durability or increase the potential for escape from vaccine-induced immunity. Using synthetic vaccinology, we have developed rationally immune-focused SARS-CoV-2 Spike-based vaccines. Glycans can be employed to alter antibody responses to infection and vaccines. Utilizing computational modeling and in vitro screening, we have incorporated glycans into the receptor-binding domain (RBD) and assessed antigenic profiles. We demonstrate that glycan-coated RBD immunogens elicit stronger neutralizing antibodies and have engineered seven multivalent configurations. Advanced DNA delivery of engineered nanoparticle vaccines rapidly elicits potent neutralizing antibodies in guinea pigs, hamsters, and multiple mouse models, including human ACE2 and human antibody repertoire transgenics. RBD nanoparticles induce high levels of cross-neutralizing antibodies against variants of concern with durable titers beyond 6 months. Single, low-dose immunization protects against a lethal SARS-CoV-2 challenge. Single-dose coronavirus vaccines via DNA-launched nanoparticles provide a platform for rapid clinical translation of potent and durable coronavirus vaccines.

SARS-CoV-2 DNA Vaccine INO-4800 Induces Durable Immune Responses Capable of Being Boosted in a Phase 1 Open-Label Trial

Background

Additional SARS-CoV-2 vaccines that are safe and effective as primary vaccines and boosters remain urgently needed to combat the COVID-19 pandemic. We describe the safety and durability of the immune responses following two primary doses and a homologous booster dose of an investigational DNA vaccine (INO-4800) targeting the full-length spike antigen.

Methods

Three dosage strengths of INO-4800 (0.5 mg, 1.0 mg, and 2.0 mg) were evaluated in 120 age-stratified healthy adults. Intradermal injection of INO-4800 followed by electroporation at 0 and 4 weeks preceded an optional booster 6-10.5 months after the second dose.

Results

INO-4800 appeared well tolerated, with no treatment-related serious adverse events. Most adverse events were mild and did not increase in frequency with age and subsequent dosing. A durable antibody response was observed 6 months following the second dose; a homologous booster dose significantly increased immune responses. Cytokine producing T cells and activated CD8+ T cells with lytic potential were significantly increased in the 2.0 mg dose group.

Conclusion

INO-4800 was well tolerated in a 2-dose primary series and as a homologous booster in all adults, including the elderly. These results support further development of INO-4800 for use as a primary vaccine and as a booster.

Efficacy and immunogenicity of MultiTEP-based DNA vaccines targeting human α-synuclein: prelude for IND enabling studies

Accumulation of misfolded proteins such as amyloid-β (Aβ), tau, and α-synuclein (α-Syn) in the brain leads to synaptic dysfunction, neuronal damage, and the onset of relevant neurodegenerative disorder/s. Dementia with Lewy bodies (DLB) and Parkinson’s disease (PD) are characterized by the aberrant accumulation of α-Syn intracytoplasmic Lewy body inclusions and dystrophic Lewy neurites resulting in neurodegeneration associated with inflammation. Cell to cell propagation of α-Syn aggregates is implicated in the progression of PD/DLB, and high concentrations of anti-α-Syn antibodies could inhibit/reduce the spreading of this pathological molecule in the brain. To ensure sufficient therapeutic concentrations of anti-α-Syn antibodies in the periphery and CNS, we developed four α-Syn DNA vaccines based on the universal MultiTEP platform technology designed especially for the elderly with immunosenescence. Here, we are reporting on the efficacy and immunogenicity of these vaccines targeting three B-cell epitopes of hα-Syn aa85–99 (PV-1947D), aa109–126 (PV-1948D), aa126–140 (PV-1949D) separately or simultaneously (PV-1950D) in a mouse model of synucleinopathies mimicking PD/DLB. All vaccines induced high titers of antibodies specific to hα-Syn that significantly reduced PD/DLB-like pathology in hα-Syn D line mice. The most significant reduction of the total and protein kinase resistant hα-Syn, as well as neurodegeneration, were observed in various brain regions of mice vaccinated with PV-1949D and PV-1950D in a sex-dependent manner. Based on these preclinical data, we selected the PV-1950D vaccine for future IND enabling preclinical studies and clinical development.

COVID-eVax, an electroporated DNA vaccine candidate encoding the SARS-CoV-2 RBD, elicits protective responses in animal models

The COVID-19 pandemic caused by SARS-CoV-2 has made the development of safe and effective vaccines a critical priority. To date, four vaccines have been approved by European and American authorities for preventing COVID-19, but the development of additional vaccine platforms with improved supply and logistics profiles remains a pressing need. Here we report the preclinical evaluation of a novel COVID-19 vaccine candidate based on the electroporation of engineered, synthetic cDNA encoding a viral antigen in the skeletal muscle. We constructed a set of prototype DNA vaccines expressing various forms of the SARS-CoV-2 spike (S) protein and assessed their immunogenicity in animal models. Among them, COVID-eVax-a DNA plasmid encoding a secreted monomeric form of SARS-CoV-2 S protein receptor-binding domain (RBD)-induced the most potent anti-SARS-CoV-2 neutralizing antibody responses (including against the current most common variants of concern) and a robust T cell response. Upon challenge with SARS-CoV-2, immunized K18-hACE2 transgenic mice showed reduced weight loss, improved pulmonary function, and lower viral replication in the lungs and brain. COVID-eVax conferred significant protection to ferrets upon SARS-CoV-2 challenge. In summary, this study identifies COVID-eVax as an ideal COVID-19 vaccine candidate suitable for clinical development. Accordingly, a combined phase I-II trial has recently started.

Techniques for Developing and Assessing Immune Responses Induced by Synthetic DNA Vaccines for Emerging Infectious Diseases

Vaccines are one of mankind's greatest medical advances, and their use has drastically reduced and in some cases eliminated (e.g., smallpox) disease and death caused by infectious agents. Traditional vaccine modalities including live-attenuated pathogen vaccines, wholly inactivated pathogen vaccines, and protein-based pathogen subunit vaccines have successfully been used to create efficacious vaccines against measles, mumps, rubella, polio, and yellow fever. These traditional vaccine modalities, however, take many months to years to develop and have thus proven less effective for use in creating vaccines to emerging or reemerging infectious diseases (EIDs) including influenza, Human immunodeficiency virus (HIV), dengue virus (DENV), chikungunya virus (CHIKV), West Nile virus (WNV), Middle East respiratory syndrome (MERS), and the severe acute respiratory syndrome coronaviruses 1 and 2 (SARS-CoV and SARS-CoV-2). As factors such as climate change and increased globalization continue to increase the pace of EID development, newer vaccine modalities are required to develop vaccines that can prevent or attenuate EID outbreaks throughout the world. One such modality, DNA vaccines, has been studied for over 30 years and has numerous qualities that make them ideal for meeting the challenge of EIDs including; (1) DNA vaccine candidates can be designed within hours of publishing of a pathogens genetic sequence; (2) they can be manufactured cheaply and rapidly in large quantities; (3) they are thermostable and have reduced requirement for a cold-chain during distribution, and (4) they have a remarkable safety record in the clinic. Optimizations made in plasmid design as well as in DNA vaccine delivery have greatly improved the immunogenicity of these vaccines. Here we describe the process of making a DNA vaccine to an EID pathogen and describe methods used for assessing the immunogenicity and protective efficacy of DNA vaccines in small animal models.

Vaccine Technologies and Platforms for Infectious Diseases: Current Progress, Challenges, and Opportunities

Vaccination is a key component of public health policy with demonstrated cost-effective benefits in protecting both human and animal populations. Vaccines can be manufactured under multiple forms including, inactivated (killed), toxoid, live attenuated, Virus-like Particles, synthetic peptide, polysaccharide, polysaccharide conjugate (glycoconjugate), viral vectored (vector-based), nucleic acids (DNA and mRNA) and bacterial vector/synthetic antigen presenting cells. Several processes are used in the manufacturing of vaccines and recent developments in medical/biomedical engineering, biology, immunology, and vaccinology have led to the emergence of innovative nucleic acid vaccines, a novel category added to conventional and subunit vaccines. In this review, we have summarized recent advances in vaccine technologies and platforms focusing on their mechanisms of action, advantages, and possible drawbacks.

Nanovaccine Delivery Approaches and Advanced Delivery Systems for the Prevention of Viral Infections: From Development to Clinical Application

Viral infections causing pandemics and chronic diseases are the main culprits implicated in devastating global clinical and socioeconomic impacts, as clearly manifested during the current COVID-19 pandemic. Immunoprophylaxis via mass immunisation with vaccines has been shown to be an efficient strategy to control such viral infections, with the successful and recently accelerated development of different types of vaccines, thanks to the advanced biotechnological techniques involved in the upstream and downstream processing of these products. However, there is still much work to be done for the improvement of efficacy and safety when it comes to the choice of delivery systems, formulations, dosage form and route of administration, which are not only crucial for immunisation effectiveness, but also for vaccine stability, dose frequency, patient convenience and logistics for mass immunisation. In this review, we discuss the main vaccine delivery systems and associated challenges, as well as the recent success in developing nanomaterials-based and advanced delivery systems to tackle these challenges. Manufacturing and regulatory requirements for the development of these systems for successful clinical and marketing authorisation were also considered. Here, we comprehensively review nanovaccines from development to clinical application, which will be relevant to vaccine developers, regulators, and clinicians.

Nucleic acid vaccines: A taboo broken and prospect for a hepatitis B virus cure

Although a prophylactic vaccine is available, hepatitis B virus (HBV) remains a major cause of liver-related morbidity and mortality. Current treatment options are improving clinical outcomes in chronic hepatitis B; however, true functional cure is currently the exception rather than the rule. Nucleic acid vaccines are among the emerging immunotherapies that aim to restore weakened immune function in chronically infected hosts. DNA vaccines in particular have shown promising results in vivo by reducing viral replication, breaking immune tolerance in a sustained manner, or even decimating the intranuclear covalently closed circular DNA reservoir, the hallmark of HBV treatment. Although DNA vaccines encoding surface antigens administered by conventional injection elicit HBV-specific T cell responses in humans, initial clinical trials failed to demonstrate additional therapeutic benefit when administered with nucleos(t)ide analogs. In an attempt to improve vaccine immunogenicity, several techniques have been used, including codon/promoter optimization, coadministration of cytokine adjuvants, plasmids engineered to express multiple HBV epitopes, or combinations with other immunomodulators. DNA vaccine delivery by electroporation is among the most efficient strategies to enhance the production of plasmid-derived antigens to stimulate a potent cellular and humoral anti-HBV response. Preliminary results suggest that DNA vaccination via electroporation efficiently invigorates both arms of adaptive immunity and suppresses serum HBV DNA. In contrast, the study of mRNA-based vaccines is limited to a few in vitro experiments in this area. Further studies are needed to clarify the prospects of nucleic acid vaccines for HBV cure.

In Vivo Electroporation of Plasmid DNA: A Promising Strategy for Rapid, Inexpensive, and Flexible Delivery of Anti-Viral Monoclonal Antibodies

Since the first approval of monoclonal antibodies by the United States Food and Drug Administration (FDA) in 1986, therapeutic antibodies have become one of the predominant classes of drugs in oncology and immunology. Despite their natural function in contributing to antiviral immunity, antibodies as drugs have only more recently been thought of as tools for combating infectious diseases. Passive immunization, or the delivery of the products of an immune response, offers near-immediate protection, unlike the active immune processes triggered by traditional vaccines, which rely on the time it takes for the host's immune system to develop an effective defense. This rapid onset of protection is particularly well suited to containing outbreaks of emerging viral diseases. Despite these positive attributes, the high cost associated with antibody manufacture and the need for a cold chain for storage and transport limit their deployment on a global scale, especially in areas with limited resources. The in vivo transfer of nucleic acid-based technologies encoding optimized therapeutic antibodies transform the body into a bioreactor for rapid and sustained production of biologics and hold great promise for circumventing the obstacles faced by the traditional delivery of antibodies. In this review, we provide an overview of the different antibody delivery strategies that are currently being developed, with particular emphasis on in vivo transfection of naked plasmid DNA facilitated by electroporation.

A brief review on DNA vaccines in the era of COVID-19

This article provides a brief overview of DNA vaccines. First, the basic DNA vaccine design strategies are described, then specific issues related to the industrial production of DNA vaccines are discussed, including the production and purification of DNA products such as plasmid DNA, minicircle DNA, minimalistic, immunologically defined gene expression (MIDGE) and Doggybone™. The use of adjuvants to enhance the immunogenicity of DNA vaccines is then discussed. In addition, different delivery routes and several physical and chemical methods to increase the efficacy of DNA delivery into cells are explained. Recent preclinical and clinical trials of DNA vaccines for COVID-19 are then summarized. Lastly, the advantages and obstacles of DNA vaccines are discussed.

Recognition of Tumor-Associated Antigens and Immune Subtypes in Glioma for mRNA Vaccine Development

Background

Although mRNA vaccines have been efficient for combating a variety of tumors, their effectiveness against glioma remains unclear. There is growing evidence that immunophenotyping can reflect the comprehensive immune status and microenvironment of the tumor, which correlates closely with treatment response and vaccination potency. The purpose of this research was to screen for effective antigens in glioma that could be used for developing mRNA vaccines and to further differentiate the immune subtypes of glioma to create an selection criteria for suitable patients for vaccination.

Methods

Gene expression profiles and clinical data of 698 glioma samples were extracted from The Cancer Genome Atlas, and RNA_seq data of 1018 glioma samples was gathered from Chinese Glioma Genome Atlas. Gene Expression Profiling Interactive Analysis was used to determine differential expression genes and prognostic markers, cBioPortal software was used to verify gene alterations, and Tumor Immune Estimation Resource was used to investigate the relationships among genes and immune infiltrating cells. Consistency clustering was applied for consistent matrix construction and data aggregation, Gene oncology enrichment was performed for functional annotation, and a graph learning-based dimensionality reduction method was applied to describe the subtypes of immunity.

Results

Four overexpressed and mutated tumor antigens associated with poor prognosis and infiltration of antigen presenting cells were identified in glioma, including TP53, IDH1, C3, and TCF12. Besides, four immune subtypes of glioma (IS1-IS4) and 10 immune gene modules were identified consistently in the TCGA data. The immune subtypes had diverse molecular, cellular, and clinical features. IS1 and IS4 displayed an immune-activating phenotype and were associated with worse survival than the other two subtypes, while IS2 and IS3 had lower levels of tumor immune infiltration. Immunogenic cell death regulators and immune checkpoints were also diversely expressed in the four immune subtypes.

Conclusion

TP53, IDH1, C3, and TCF12 are effective antigens for the development of anti-glioma mRNA vaccines. We found four stable and repeatable immune subtypes of human glioma, the classification of the immune subtypes of glioma may play a crucial role in the predicting mRNA vaccine outcome.

Strategic Variants of CSP Delivered as SynDNA Vaccines Demonstrate Heterogeneity of Immunogenicity and Protection from Plasmodium Infection in a Murine Model

Malaria infects millions of people every year, and despite recent advances in controlling disease spread, such as vaccination, it remains a global health concern. The circumsporozoite protein (CSP) has long been acknowledged as a key target in antimalarial immunity. Leveraging the DNA vaccine platform against this formidable pathogen, the following five synthetic DNA vaccines encoding variations of CSP were designed and studied: 3D7, GPI1, ΔGPI, TM, and DD2. Among the single CSP antigen constructs, a range of immunogenicity was observed with ΔGPI generating the most robust immunity. In an intravenous (i.v.) sporozoite challenge, the best protection among vaccinated mice was achieved by ΔGPI, which performed almost as well as the monoclonal antibody 311 (MAb 311) antibody control. Further analyses revealed that ΔGPI develops high-molecular-weight multimers in addition to monomeric CSP. We then compared the immunity generated by ΔGPI versus synDNA mimics for the antimalaria vaccines RTS,S and R21. The anti-CSP antibody responses induced were similar among these three immunogens. T cell responses demonstrated that ΔGPI induced a more focused anti-CSP response. In an infectious mosquito challenge, all three of these constructs generated inhibition of liver-stage infection as well as immunity from blood-stage parasitemia. This study demonstrates that synDNA mimics of complex malaria immunogens can provide substantial protection as can a novel synDNA vaccine ΔGPI.

COVID-19 vaccine platforms: Delivering on a promise?

The emergence of the novel SARS-CoV-2 and COVID-19 has brought into sharp focus the need for a vaccine to prevent this disease. Vaccines have saved millions of lives since their introduction to the public over 200 years ago. The potential for vaccination reached new heights in the mid-20th century with the development of technologies that expanded the ability to create novel vaccines. Since then, there has been continued technological advancement in vaccine development. The resulting platforms provide the promise for solutions for many infectious diseases, including those that have been with us for decades as well as those just now emerging. Each vaccine platform represents a different technology with a unique set of advantages and challenges, especially when considering manufacturing. Therefore, it is essential to understand each platform as a separate product and process with its specific quality considerations. This review outlines the relevant platforms for developing a vaccine for SARS-CoV-2 and discusses the advantages and disadvantages of each.

The impact of Vaccination worldwide on SARS-CoV-2 infection: A Review on Vaccine Mechanisms, Results of Clinical Trials, Vaccinal Coverage and Interactions with Novel Variants

BACKGROUND

The COVID-19 pandemic demanded a global effort towards quickly developing safe and effective vaccines against SARS-CoV-2.

OBJECTIVE

This review aimed to discuss the main vaccines available, their mechanisms of action, results of clinical trials and epidemiological behavior. The implications of viral variants were also debated.

METHODS

A non-systematic literature review was performed between February and March 2021 by searching the Pubmed, Scopus, and SciELO databases, using different combinations of the following terms: "vaccines", "clinical trials" , "SARS-CoV-2", "Coronavirus", "COVID-19", "mechanisms of action". Data regarding clinical trials of SARS-CoV-2 vaccines and epidemiological information were also searched.

RESULTS

The mechanisms of action included vector-virus, mRNA and inactivated virus vaccines. The vaccines showed positive results in phases 2/3 clinical trials. The efficacy of the mRNA 1273 and of mRNA BNT 162b2 vaccines were 94.1% and 95%, respectively. The effectiveness of the ChAdOx1 nCoV-19 vaccine varied according to the scheme, with an overall value of 70.4%. The Gam-COVID-Vac vaccine had an efficacy of 91.6%. Regarding the Ad26.COV2.S vaccine, 99% or more of seroconversion was observed in all subgroups 29 days after vaccination. The CoronaVac vaccine induced an immune response in 92% of the volunteers receiving 3ug and in 98% with 6ug, in comparison to 3% in the placebo group.

CONCLUSION

Global efforts have resulted in vaccines available in record time, with good safety and immunogenicity profile. However, only long-term studies can provide more information on duration of immunity and the need for additional doses.

A Therapeutic Hepatitis B Virus DNA Vaccine Induces Specific Immune Responses in Mice and Non-Human Primates

Despite the availability of an effective prophylactic vaccine for more than 30 years, nearly 300 million people worldwide are chronically infected with the hepatitis B virus (HBV), leading to 1 death every 30 s mainly from viral hepatitis-related cirrhosis and liver cancer. Chronic HBV patients exhibit weak, transient, or dysfunctional CD8⁺ T-cell responses to HBV, which contrasts with high CD8+ T-cell responses seen for resolvers of acute HBV infection. Therefore, a therapeutic DNA vaccine was designed, expressing both HBV core and polymerase proteins, and was sequence optimized to ensure high protein expression and secretion. Although the vaccine, administered intramuscularly via electroporation, had no effect on plasma viral parameters in a mouse model of persistent HBV infection, it did induce robust HBV-specific immune responses in healthy and adeno-associated hepatitis B virus (AAV-HBV) infected mice as well as in healthy non-human primates.

DNA Vaccine Administered by Cationic Lipoplexes or by In Vivo Electroporation Induces Comparable Antibody Responses against SARS-CoV-2 in Mice

In view of addressing the global necessity of an effective vaccine in the SARS-CoV-2 pandemic, a plasmid DNA vaccine, expressing for the spike (S) protein and formulated in lipoplexes, was manufactured and tested for in vitro transfection and in vivo immunogenicity. Blank cationic liposomes of 130.9 ± 5.8 nm in size and with a zeta potential of +48 ± 12 mV were formulated using the thin-film layer rehydration method. Liposomes were complexed with pCMVkan-S at different N/P ratios. Ratios of 0.25:1 and 1:1 were selected according to their complex stability and controlled size compared to other ratios and tested in vitro for transfection studies and in vivo for immunogenicity. Both selected formulations showed enhanced neutralizing antibody responses compared to pCMVkan-S injected alone, as well as an increased T cell response. The titers observed were similar to those of intramuscular electroporation (IM-EP), which was set as an efficacy goal.

Combining Cancer Vaccines with Immunotherapy: Establishing a New Immunological Approach

Therapeutic cancer vaccines have become increasingly qualified for use in personalized cancer immunotherapy. A deeper understanding of tumor immunology and novel antigen delivery technologies has assisted in optimizing vaccine design. Therapeutic cancer vaccines aim to establish long-lasting immunological memory against tumor cells, thereby leading to effective tumor regression and minimizing non-specific or adverse events. However, due to several resistance mechanisms, significant challenges remain to be solved in order to achieve these goals. In this review, we describe our current understanding with respect to the use of the antigen repertoire in vaccine platform development. We also summarize various intrinsic and extrinsic resistance mechanisms behind the failure of cancer vaccine development in the past. Finally, we suggest a strategy that combines immune checkpoint inhibitors to enhance the efficacy of cancer vaccines.

Platforms for Production of Protein-Based Vaccines: From Classical to Next-Generation Strategies

To date, vaccination has become one of the most effective strategies to control and reduce infectious diseases, preventing millions of deaths worldwide. The earliest vaccines were developed as live-attenuated or inactivated pathogens, and, although they still represent the most extended human vaccine types, they also face some issues, such as the potential to revert to a pathogenic form of live-attenuated formulations or the weaker immune response associated with inactivated vaccines. Advances in genetic engineering have enabled improvements in vaccine design and strategies, such as recombinant subunit vaccines, have emerged, expanding the number of diseases that can be prevented. Moreover, antigen display systems such as VLPs or those designed by nanotechnology have improved the efficacy of subunit vaccines. Platforms for the production of recombinant vaccines have also evolved from the first hosts, Escherichia coli and Saccharomyces cerevisiae, to insect or mammalian cells. Traditional bacterial and yeast systems have been improved by engineering and new systems based on plants or insect larvae have emerged as alternative, low-cost platforms. Vaccine development is still time-consuming and costly, and alternative systems that can offer cost-effective and faster processes are demanding to address infectious diseases that still do not have a treatment and to face possible future pandemics.

Red Blood Cell Hitchhiking: A Novel Approach for Vascular Delivery of Nanocarriers

Red blood cell (RBC) hitchhiking is a method of drug delivery that can increase drug concentration in target organs by orders of magnitude. In RBC hitchhiking, drug-loaded nanoparticles (NPs) are adsorbed onto red blood cells and then injected intravascularly, which causes the NPs to transfer to cells of the capillaries in the downstream organ. RBC hitchhiking has been demonstrated in multiple species and multiple organs. For example, RBC-hitchhiking NPs localized at unprecedented levels in the brain when using intra-arterial catheters, such as those in place immediately after mechanical thrombectomy for acute ischemic stroke. RBC hitchhiking has been successfully employed in numerous preclinical models of disease, ranging from pulmonary embolism to cancer metastasis. In addition to summarizing the versatility of RBC hitchhiking, we also describe studies into the surprisingly complex mechanisms of RBC hitchhiking as well as outline future studies to further improve RBC hitchhiking's clinical utility.

A single subcutaneous or intranasal immunization with adenovirus-based SARS-CoV-2 vaccine induces robust humoral and cellular immune responses in mice

Optimal vaccines are needed for sustained suppression of SARS-CoV-2 and other novel coronaviruses. Here, we developed a recombinant type 5 adenovirus vector encoding the gene for the SARS-CoV-2 S1 subunit antigen (Ad5.SARS-CoV-2-S1) for COVID-19 immunization and evaluated its immunogenicity in mice. A single immunization with Ad5.SARS-CoV-2-S1 via S.C. injection or I.N delivery induced robust antibody and cellular immune responses. Vaccination elicited significant S1-specific IgG, IgG1, and IgG2a endpoint titers as early as 2 weeks, and the induced antibodies were long lasting. I.N. and S.C. administration of Ad5.SARS-CoV-2-S1 produced S1-specific GC B cells in cervical and axillary LNs, respectively. Moreover, I.N. and S.C. immunization evoked significantly greater antigen-specific T-cell responses compared to unimmunized control groups with indications that S.C. injection was more effective than I.N. delivery in eliciting cellular immune responses. Mice vaccinated by either route demonstrated significantly increased virus-specific neutralization antibodies on weeks 8 and 12 compared to control groups, as well as BM antibody forming cells (AFC), indicative of long-term immunity. Thus, this Ad5-vectored SARS-CoV-2 vaccine candidate showed promising immunogenicity following delivery to mice by S.C. and I.N. routes of administration, supporting the further development of Ad-based vaccines against COVID-19 and other infectious diseases for sustainable global immunization programs.

Nano-therapeutic strategies to target coronavirus

The coronaviruses have caused severe acute respiratory syndrome (SARS), the Middle East respiratory syndrome (MERS), and the more recent coronavirus pneumonia (COVID-19). The global COVID-19 pandemic requires urgent action to develop anti-virals, new therapeutics, and vaccines. In this review, we discuss potential therapeutics including human recombinant ACE2 soluble, inflammatory cytokine inhibitors, and direct anti-viral agents such as remdesivir and favipiravir, to limit their fatality. We also discuss the structure of the SARS-CoV-2, which is crucial to the timely development of therapeutics, and previous attempts to generate vaccines against SARS-CoV and MERS-CoV. Finally, we provide an overview of the role of nanotechnology in the development of therapeutics as well as in the diagnosis of the infection. This information is key for computational modeling and nanomedicine-based new therapeutics by counteracting the variable proteins in the virus. Further, we also try to effectively share the latest information about many different aspects of COVID-19 vaccine developments and possible management to further scientific endeavors.

DNA vaccination induced protective immunity against SARS CoV-2 infection in hamsterss

The development of efficient vaccines against COVID-19 is an emergent need for global public health. The spike protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a major target for the COVID-19 vaccine. To quickly respond to the outbreak of the SARS-CoV-2 pandemic, a nucleic acid-based vaccine is a novel option, beyond the traditional inactivated virus vaccine or recombinant protein vaccine. Here, we report a DNA vaccine containing the spike gene for delivery via electroporation. The spike genes of SARS-CoV and SARS-CoV-2 were codon optimized for mammalian cell expression and then cloned into mammalian cell expression vectors, called pSARS-S and pSARS2-S, respectively. Spike protein expression was confirmed by immunoblotting after transient expression in HEK293T cells. After immunization, sera were collected for antigen-specific antibody and neutralizing antibody titer analyses. We found that both pSARS-S and pSARS2-S immunization induced similar levels of antibodies against S2 of SARS-CoV-2. In contrast, only pSARS2-S immunization induced antibodies against the receptor-binding domain of SARS-CoV-2. We further found that pSARS2-S immunization, but not pSARS-S immunization, could induce very high titers of neutralizing antibodies against SARS-CoV-2. We further analyzed SARS-CoV-2 S protein-specific T cell responses and found that the immune responses were biased toward Th1. Importantly, pSARS2-S immunization in hamsters could induce protective immunity against SARS-CoV-2 challenge in vivo. These data suggest that DNA vaccination could be a promising approach for protecting against COVID-19.

Immunopeptidomics for next-generation bacterial vaccine development

Antimicrobial resistance is an increasing global threat and alternative treatments substituting failing antibiotics are urgently needed. Vaccines are recognized as highly effective tools to mitigate antimicrobial resistance; however, the selection of bacterial antigens as vaccine candidates remains challenging. In recent years, advances in mass spectrometry-based proteomics have led to the development of so-called immunopeptidomics approaches that allow the untargeted discovery of bacterial epitopes that are presented on the surface of infected cells. Especially for intracellular bacterial pathogens, immunopeptidomics holds great promise to uncover antigens that can be encoded in viral vector- or nucleic acid-based vaccines. This review provides an overview of immunopeptidomics studies on intracellular bacterial pathogens and considers future directions and challenges in advancing towards next-generation vaccines.

[Review of candidate vaccines for the prevention of Lassa fever]

The Lassa virus one of the main etiological agent of hemorrhagic fevers in the world: according to WHO estimates, it affects 100,000 to 300,000 people annually, which results in up to 10,000 deaths [1]. Although expansion of Lassa fever caused by this pathogen is mostly limited to the West African countries: Sierra Leone, Liberia, Guinea and Nigeria, imported cases have been historically documented in Europe, the United States of America (USA), Canada, Japan, and Israel [2]. In 2017, WHO included the Lassa virus in the list of priority pathogens in need of accelerated research, development of vaccines, therapeutic agents and diagnostic tools regarding infections they cause [3]. This review describes main technological platforms used for the development of vaccines for the prevention of Lassa fever.

Advances in the development of personalized neoantigen-based therapeutic cancer vaccines

Within the past decade, the field of immunotherapy has revolutionized the treatment of many cancers with the development and regulatory approval of various immune-checkpoint inhibitors and chimeric antigen receptor T cell therapies in diverse indications. Another promising approach to cancer immunotherapy involves the use of personalized vaccines designed to trigger de novo T cell responses against neoantigens, which are highly specific to tumours of individual patients, in order to amplify and broaden the endogenous repertoire of tumour-specific T cells. Results from initial clinical studies of personalized neoantigen-based vaccines, enabled by the availability of rapid and cost-effective sequencing and bioinformatics technologies, have demonstrated robust tumour-specific immunogenicity and preliminary evidence of antitumour activity in patients with melanoma and other cancers. Herein, we provide an overview of the complex process that is necessary to generate a personalized neoantigen vaccine, review the types of vaccine-induced T cells that are found within tumours and outline strategies to enhance the T cell responses. In addition, we discuss the current status of clinical studies testing personalized neoantigen vaccines in patients with cancer and considerations for future clinical investigation of this novel, individualized approach to immunotherapy.

Vaccines: Underlying Principles of Design and Testing

In this paper, we review the key elements that should be considered to take a novel vaccine from the laboratory through to licensure in the modern era. This paper is divided into four sections. First, we discuss the host immune responses that we engage with vaccines. Second, we discuss how in vivo and in vitro studies can inform vaccine design. Third, we discuss different vaccine modalities that have been licensed or are in testing in humans. Last, we overview the basic principles of vaccine approvals. Throughout we provide real-world examples of vaccine development against infectious diseases, including coronavirus disease 2019 (COVID-19).

Advances in the development of personalized neoantigen-based therapeutic cancer vaccines

Within the past decade, the field of immunotherapy has revolutionized the treatment of many cancers with the development and regulatory approval of various immune-checkpoint inhibitors and chimeric antigen receptor T cell therapies in diverse indications. Another promising approach to cancer immunotherapy involves the use of personalized vaccines designed to trigger de novo T cell responses against neoantigens, which are highly specific to tumours of individual patients, in order to amplify and broaden the endogenous repertoire of tumour-specific T cells. Results from initial clinical studies of personalized neoantigen-based vaccines, enabled by the availability of rapid and cost-effective sequencing and bioinformatics technologies, have demonstrated robust tumour-specific immunogenicity and preliminary evidence of antitumour activity in patients with melanoma and other cancers. Herein, we provide an overview of the complex process that is necessary to generate a personalized neoantigen vaccine, review the types of vaccine-induced T cells that are found within tumours and outline strategies to enhance the T cell responses. In addition, we discuss the current status of clinical studies testing personalized neoantigen vaccines in patients with cancer and considerations for future clinical investigation of this novel, individualized approach to immunotherapy.

DNA Nanodevices with Selective Immune Cell Interaction and Function

DNA nanotechnology produces precision nanostructures of defined chemistry. Expanding their use in biomedicine requires designed biomolecular interaction and function. Of topical interest are DNA nanostructures that function as vaccines with potential advantages over nonstructured nucleic acids in terms of serum stability and selective interaction with human immune cells. Here, we describe how compact DNA nanobarrels bind with a 400-fold selectivity via membrane anchors to white blood immune cells over erythrocytes, without affecting cell viability. The selectivity is based on the preference of the cholesterol lipid anchor for the more fluid immune cell membranes compared to the lower membrane fluidity of erythrocytes. Compacting DNA into the nanostructures gives rise to increased serum stability. The DNA barrels furthermore functionally modulate white blood cells by suppressing the immune response to pro-inflammatory endotoxin lipopolysaccharide. This is likely due to electrostatic or steric blocking of toll-like receptors on white blood cells. Our findings on immune cell-specific DNA nanostructures may be applied for vaccine development, immunomodulatory therapy to suppress septic shock, or the targeting of bioactive substances to immune cells.

Optimization of Zika DNA vaccine by delivery systems

In our previous study, we designed and evaluated the efficacy of six DNA vaccine candidates based on the E protein of Zika virus (ZIKV). To optimize the DNA vaccine, we inoculated C57BL/6 and IFNAR1^- mice with the vaccine candidate expressing tandem repeated ZIKV envelope domain III (ED III × 3) doses; 50 μg by intramuscular (IM), jet injection (JET), or electroporation (EP) routes. Results showed that vaccination by all routes induced humoral and cellular immunity. Among them, EP induced robust ZIKV E specific-total IgG and neutralizing antibodies, as well as T cell responses. Additionally, EP showed superior protective efficacy against the ZIKV Brazil strain compared to the IM and JET routes. Finally, in the dose optimization test of EP route, cellular immunity of 50 μg was induced a significant level than other dose groups. These results showed that the EP delivery system enhanced the potential immunogenicity and protective efficacy of DNA vaccines.

CrossTORC and WNTegration in Disease: Focus on Lymphangioleiomyomatosis

The mechanistic target of rapamycin (mTOR) and wingless-related integration site (Wnt) signal transduction networks are evolutionarily conserved mammalian growth and cellular development networks. Most cells express many of the proteins in both pathways, and this review will briefly describe only the key proteins and their intra- and extracellular crosstalk. These complex interactions will be discussed in relation to cancer development, drug resistance, and stem cell exhaustion. This review will also highlight the tumor-suppressive tuberous sclerosis complex (TSC) mutated, mTOR-hyperactive lung disease of women, lymphangioleiomyomatosis (LAM). We will summarize recent advances in the targeting of these pathways by monotherapy or combination therapy, as well as future potential treatments.

Review on Up-to-Date Status of Candidate Vaccines for COVID-19 Disease

The global pandemic of COVID-19 caused by SARS-CoV-2 continues to spread and poses serious threats to public health and economic stability throughout the world. Thus, to protect the global population, developing safe and effective vaccines is mandatory to control the spread of SARS-CoV-2 pandemic. Since genomic sequences of SARS-CoV-2 and SARS-CoV-1 have similarity and use the same receptor (ACE2), it is important to learn from the development of SARS-CoV-1 vaccines for the development of SARS-CoV-2 vaccines. Normally vaccine development takes 10-15 years but vaccine development against SARS-CoV2 is going on at a very fast pace resulting in almost breakthrough methods of vaccine development by several research institutions. The whole process of vaccine development including clinical trials gets shortened and may be fast tracked to 15-18 months. Global collaborations and increased research efforts among the scientific community have led to more than 214 candidate vaccines globally. The current review highlights the different approaches and technologies used around the world for the design and development of the vaccines and also focuses on the recent status of the SARS-CoV-2 vaccine candidates under development by various institutions to combat the world threat of COVID-19 pandemic.

Priming with DNA Expressing Trimeric HIV V1V2 Alters the Immune Hierarchy Favoring the Development of V2-Specific Antibodies in Rhesus Macaques

The RV144 vaccine trial revealed a correlation between reduced risk of HIV infection and the level of nonneutralizing-antibody (Ab) responses targeting specific epitopes in the second variable domain (V2) of the HIV gp120 envelope (Env) protein, suggesting this region as a target for vaccine development. To favor induction of V2-specific Abs, we developed a vaccine regimen that included priming with DNA expressing an HIV V1V2 trimeric scaffold immunogen followed by booster immunizations with a combination of DNA and protein in rhesus macaques. Priming vaccination with DNA expressing the HIV recombinant subtype CRF01_AE V1V2 scaffold induced higher and broader V2-specific Ab responses than vaccination with DNA expressing CRF01_AE gp145 Env. Abs recognizing the V2 peptide that was reported as a critical target in RV144 developed only after the priming immunization with V1V2 DNA. The V2-specific Abs showed several nonneutralizing Fc-mediated functions, including ADCP and C1q binding. Importantly, robust V2-specific Abs were maintained upon boosting with gp145 DNA and gp120 protein coimmunization. In conclusion, priming with DNA expressing the trimeric V1V2 scaffold alters the hierarchy of humoral immune responses to V2 region epitopes, providing a method for more efficient induction and maintenance of V2-specific Env Abs associated with reduced risk of HIV infection.IMPORTANCE The aim of this work was to design and test a vaccine regimen focusing the immune response on targets associated with infection prevention. We demonstrated that priming with a DNA vaccine expressing only the HIV Env V1V2 region induces Ab responses targeting the critical region in V2 associated with protection. This work shows that V1V2 scaffold DNA priming immunization provides a method to focus immune responses to the desired target region, in the absence of immune interference by other epitopes. This induced immune responses with improved recognition of epitopes important for protective immunity, namely, V2-specific humoral immune responses inversely correlating with HIV risk of infection in the RV144 trial.

Intramuscular and Intradermal Electroporation of HIV-1 PENNVAX-GP® DNA Vaccine and IL-12 Is Safe, Tolerable, Acceptable in Healthy Adults

Background: Several techniques are under investigation to improve the immunogenicity of HIV-1 DNA vaccine candidates. DNA vaccines are advantageous due to their ease of design, expression of multiple antigens, and safety.

METHODS

The HVTN 098 trial assessed the PENNVAX^®-GP DNA vaccine (encoding HIV env, gag, pol) administered with or without plasmid IL-12 at 0-, 1-, 3-, and 6-month timepoints via intradermal (ID) or intramuscular (IM) electroporation (EP) in healthy, adult participants. We report on safety, tolerability, and acceptability.

RESULTS

HVTN 098 enrolled 94 participants: 85 received PENNVAX^®-GP and nine received placebo. Visual analog scale (VAS) pain scores immediately after each vaccination were lower in the ID/EP than in the IM/EP group (medians 4.1-4.6 vs. 6-6.5, p < 0.01). IM/EP participants reported greater pain and/or tenderness at the injection site. Most ID/EP participants had skin lesions such as scabs/eschars, scars, and pigmentation changes, which resolved within 6 months in 51% of participants (24/55). Eighty-two percent of IM/EP and 92% of ID/EP participant survey responses showed acceptable levels of discomfort.

CONCLUSIONS

ID/EP and IM/EP are distinct experiences; however, HIV-1 DNA vaccination by either route was safe, tolerable and acceptable by most study participants.

A novel liposome-polymer hybrid nanoparticles delivering a multi-epitope self-replication DNA vaccine and its preliminary immune evaluation in experimental animals

DNA vaccine is an attractive immune platform for the prevention and treatment of infectious diseases, but existing disadvantages limit its use in preclinical and clinical assays, such as weak immunogenicity and short half-life. Here, we reported a novel liposome-polymer hybrid nanoparticles (pSFV-MEG/LNPs) consisting of a biodegradable core (mPEG-PLGA) and a hydrophilic shell (lecithin/PEG-DSPE-Mal 2000) for delivering a multi-epitope self-replication DNA vaccine (pSFV-MEG). The pSFV-MEG/LNPs with optimal particle size (161.61 ± 15.63 nm) and high encapsulation efficiency (87.60 ± 8.73%) induced a strong humoral (3.22-fold) and cellular immune responses (1.60-fold) compared to PBS. Besides, the humoral and cellular immune responses of pSFV-MEG/LNPs were 1.58- and 1.05-fold than that of pSFV-MEG. All results confirmed that LNPs was a very promising tool to enhance the humoral and cellular immune responses of pSFV-MEG. In addition, the rational design and delivery platform can be used for the development of DNA vaccines for other infectious diseases.

In Vivo Validation of a Reversible Small Molecule-Based Switch for Synthetic Self-Amplifying mRNA Regulation

Synthetic mRNA therapeutics have the potential to revolutionize healthcare, as they enable patients to produce therapeutic proteins inside their own bodies. However, convenient methods that allow external control over the timing and magnitude of protein production after in vivo delivery of synthetic mRNA are lacking. In this study, we validate the in vivo utility of a synthetic self-amplifying mRNA (RNA replicon) whose expression can be turned off using a genetic switch that responds to oral administration of trimethoprim (TMP), a US Food and Drug Administration (FDA)-approved small-molecule drug. After intramuscular electroporation, the engineered RNA replicon exhibited dose-dependent and reversible expression of its encoded protein upon TMP administration. The TMP serum level needed for maximal downregulation of protein translation was approximately 45-fold below that used in humans for therapeutic purposes. To demonstrate the therapeutic potential of the technology, we injected mice with a TMP-responsive RNA replicon encoding erythropoietin (EPO) and successfully controlled the timing and magnitude of EPO production as well as changes in hematocrit. This work demonstrates the feasibility of controlling mRNA kinetics in vivo, thereby broadly expanding the clinical versatility of mRNA therapeutics.

Heterologous prime-boost immunization co-targeting dual antigens inhibit tumor growth and relapse

Therapeutic cancer vaccines aim to induce an effective immune response against cancer, and the effectiveness of these vaccines is influenced by the choice of immunogen, vaccine type, and immunization strategy. Although treatment with cancer vaccines can improve tumor burden and survival, in most animal studies, it is challenging to achieve a complete response against tumor growth and recurrence, without the use of other therapies in combination. Here, we present a novel approach where dual antigens (survivin and MUC1) are co-targeted using three DNA vaccines, followed by a single booster of a recombinant modified vaccinia Ankara (MVA) vaccine. This heterologous vaccination strategy induced higher levels of interferon (IFN)-γ-secretion and stronger antigen-specific T-cell responses than those induced individually by the DNA vaccines and the MVA vaccine in mice. This strategy also increased the number of active tumor-infiltrating T cells that efficiently inhibit tumor growth in tumor-bearing mice. Heterologous DNA prime-MVA boost immunization was capable of inducing a robust antigen-specific immune-memory, as seen from the resistance to subsequent survivin- and MUC1-expressing tumors. Moreover, the therapeutic effects of DNA prime-MVA boost and DNA prime-adenovirus boost strategies were compared. DNA prime-MVA boost immunization performed better, as indicated by the T effector ratio and the induction of Th1 immunity. This study provides the basis for the use of heterologous DNA prime-MVA boost vaccination regime targeting two antigens simultaneously as a promising immunotherapeutic strategy against cancer.

Immune responses and protective effects against Japanese encephalitis induced by a DNA vaccine encoding the prM/E proteins of the attenuated SA14-14-2 strain

Japanese encephalitis virus (JEV) is the causal pathogen of Japanese encephalitis (JE), which has become a severe public health problem and is one of the most rapidly spreading mosquito-borne diseases worldwide. Currently, there is no specific treatment for JEV. A vaccine would be an effective measure for reducing morbidity and mortality. Although the live attenuated vaccine SA14-14-2 has been approved in some countries, it is still necessary to develop safer, more effective, and less costly vaccines. In this study, a DNA vaccine candidate, pV-SA14ME, expressing the prM/E proteins of SA14-14-2 was inoculated into BALB/c mice via intramuscular electroporation, and the immunogenicity and degree of protection were evaluated. We found that administration of 50 μg pV-SA14ME via electroporation via three immunizations could induce persistent humoral and cellular immune responses and effectively protect mice against lethal JEV challenge. This study provides a basis for the subsequent promotion and use of the vaccine and lays the foundation for its further use in swine and humans.

Engineering Antiviral Vaccines

Despite the vital role of vaccines in fighting viral pathogens, effective vaccines are still unavailable for many infectious diseases. The importance of vaccines cannot be overstated during the outbreak of a pandemic, such as the coronavirus disease 2019 (COVID-19) pandemic. The understanding of genomics, structural biology, and innate/adaptive immunity have expanded the toolkits available for current vaccine development. However, sudden outbreaks and the requirement of population-level immunization still pose great challenges in today's vaccine designs. Well-established vaccine development protocols from previous experiences are in place to guide the pipelines of vaccine development for emerging viral diseases. Nevertheless, vaccine development may follow different paradigms during a pandemic. For example, multiple vaccine candidates must be pushed into clinical trials simultaneously, and manufacturing capability must be scaled up in early stages. Factors from essential features of safety, efficacy, manufacturing, and distributions to administration approaches are taken into consideration based on advances in materials science and engineering technologies. In this review, we present recent advances in vaccine development by focusing on vaccine discovery, formulation, and delivery devices enabled by alternative administration approaches. We hope to shed light on developing better solutions for faster and better vaccine development strategies through the use of biomaterials, biomolecular engineering, nanotechnology, and microfabrication techniques.

Harnessing Recent Advances in Synthetic DNA and Electroporation Technologies for Rapid Vaccine Development Against COVID-19 and Other Emerging Infectious Diseases

DNA vaccines are considered as a third-generation vaccination approach in which antigenic materials are encoded as DNA plasmids for direct in vivo production to elicit adaptive immunity. As compared to other platforms, DNA vaccination is considered to have a strong safety profile, as DNA plasmids neither replicate nor elicit vector-directed immune responses in hosts. While earlier work found the immune responses induced by DNA vaccines to be sub-optimal in larger mammals and humans, recent developments in key synthetic DNA and electroporation delivery technologies have now allowed DNA vaccines to elicit significantly more potent and consistent responses in several clinical studies. This paper will review findings from the recent clinical and preclinical studies on DNA vaccines targeting emerging infectious diseases (EID) including COVID-19 caused by the SARS-CoV-2 virus, and the technological advancements pivotal to the improved responses-including the use of the advanced delivery technology, DNA-encoded cytokine/mucosal adjuvants, and innovative concepts in immunogen design. With continuous advancement over the past three decades, the DNA approach is now poised to develop vaccines against COVID-19, as well as other EIDs.

Soil-Transmitted Helminth Vaccines: Are We Getting Closer?

Parasitic helminths infect over one-fourth of the human population resulting in significant morbidity, and in some cases, death in endemic countries. Despite mass drug administration (MDA) to school-aged children and other control measures, helminth infections are spreading into new areas. Thus, there is a strong rationale for developing anthelminthic vaccines as cost-effective, long-term immunological control strategies, which, unlike MDA, are not haunted by the threat of emerging drug-resistant helminths nor limited by reinfection risk. Advances in vaccinology, immunology, and immunomics include the development of new tools that improve the safety, immunogenicity, and efficacy of vaccines; and some of these tools have been used in the development of helminth vaccines. The development of anthelminthic vaccines is fraught with difficulty. Multiple lifecycle stages exist each presenting stage-specific antigens. Further, helminth parasites are notorious for their ability to dampen down and regulate host immunity. One of the first significant challenges in developing any vaccine is identifying suitable candidate protective antigens. This review explores our current knowledge in lead antigen identification and reports on recent pre-clinical and clinical trials in the context of the soil-transmitted helminths Trichuris, the hookworms and Ascaris. Ultimately, a multivalent anthelminthic vaccine could become an essential tool for achieving the medium-to long-term goal of controlling, or even eliminating helminth infections.

On Complex Coacervate Core Micelles: Structure-Function Perspectives

The co-assembly of ionic-neutral block copolymers with oppositely charged species produces nanometric colloidal complexes, known, among other names, as complex coacervates core micelles (C3Ms). C3Ms are of widespread interest in nanomedicine for controlled delivery and release, whilst research activity into other application areas, such as gelation, catalysis, nanoparticle synthesis, and sensing, is increasing. In this review, we discuss recent studies on the functional roles that C3Ms can fulfil in these and other fields, focusing on emerging structure-function relations and remaining knowledge gaps.