The NIH-led research response to COVID-19

Investment, collaboration, and coordination have been key.

A pan-serotype antiviral to prevent and treat dengue: A journey from discovery to clinical development driven by public-private partnerships

While progress has been made in fighting diseases disproportionally affecting underserved populations, unmet medical needs persist for many neglected tropical diseases. The World Health Organization has encouraged strong public-private partnerships to address this issue and several public and private organizations have set an example in the past showing a strong commitment to combat these diseases. Pharmaceutical companies are contributing in different ways to address the imbalance in research efforts. With this review, we exemplify the role of a public-private partnership in research and development by the journey of our dengue antiviral molecule that is now in early clinical development. We detail the different steps of drug development and outline the contribution of each partner to this process. Years of intensive collaboration resulted in the identification of two antiviral compounds, JNJ-A07 and JNJ-1802, the latter of which has advanced to clinical development.

Digital health technology used in emergency large-scale vaccination campaigns in low- and middle-income countries: a narrative review for improved pandemic preparedness

INTRODUCTION

Large-scale vaccination campaigns can benefit from using digital health tools, particularly in low- and middle-income countries (LMICs). Selecting the best tool to fit into a pre-existing digital landscape can be challenging.

AREAS COVERED

We conducted a narrative review in PubMed and the grey literature for data available within 5 years to provide an overview of digital health tools used in large-scale vaccination campaigns for outbreak response in LMICs. We discuss tools used along the typical steps of a vaccination process. Digital tool functionalities and technical specifications, open-source options, data privacy and security concerns, and lessons learned from the use of these tools are discussed.

EXPERT OPINION

The landscape of digital health tools for large-scale vaccination processes in LMICs is growing. For efficient implementation, countries should prioritize the appropriate tool(s) depending on their needs and available resources, develop a robust framework around data privacy and security, and select sustainable features. Improving internet connectivity and digital literacy in LMICs will facilitate adoption. This review may aid LMICs still needing to prepare large-scale vaccination campaigns in the selection of supporting digital health tools. Further research on impact and cost-effectiveness is needed.

An introduction to the Marburg virus vaccine consortium, MARVAC

The emergence of Marburg virus (MARV) in Guinea and Ghana triggered the assembly of the MARV vaccine "MARVAC" consortium representing leaders in the field of vaccine research and development aiming to facilitate a rapid response to this infectious disease threat. Here, we discuss current progress, challenges, and future directions for MARV vaccines.

Efficacy and Safety of Ensovibep for Adults Hospitalized With COVID-19 : A Randomized Controlled Trial

BACKGROUND

Ensovibep (MP0420) is a designed ankyrin repeat protein, a novel class of engineered proteins, under investigation as a treatment of SARS-CoV-2 infection.

OBJECTIVE

To investigate if ensovibep, in addition to remdesivir and other standard care, improves clinical outcomes among patients hospitalized with COVID-19 compared with standard care alone.

DESIGN

Double-blind, randomized, placebo-controlled, clinical trial. (ClinicalTrials.gov: NCT04501978).

SETTING

Multinational, multicenter trial.

PARTICIPANTS

Adults hospitalized with COVID-19.

INTERVENTION

Intravenous ensovibep, 600 mg, or placebo.

MEASUREMENTS

Ensovibep was assessed for early futility on the basis of pulmonary ordinal scores at day 5. The primary outcome was time to sustained recovery through day 90, defined as 14 consecutive days at home or place of usual residence after hospital discharge. A composite safety outcome that included death, serious adverse events, end-organ disease, and serious infections was assessed through day 90.

RESULTS

An independent data and safety monitoring board recommended that enrollment be halted for early futility after 485 patients were randomly assigned and received an infusion of ensovibep (n = 247) or placebo (n = 238). The odds ratio (OR) for a more favorable pulmonary outcome in the ensovibep (vs. placebo) group at day 5 was 0.93 (95% CI, 0.67 to 1.30; P = 0.68; OR > 1 would favor ensovibep). The 90-day cumulative incidence of sustained recovery was 82% for ensovibep and 80% for placebo (subhazard ratio [sHR], 1.06 [CI, 0.88 to 1.28]; sHR > 1 would favor ensovibep). The primary composite safety outcome at day 90 occurred in 78 ensovibep participants (32%) and 70 placebo participants (29%) (HR, 1.07 [CI, 0.77 to 1.47]; HR < 1 would favor ensovibep).

LIMITATION

The trial was prematurely stopped because of futility, limiting power for the primary outcome.

CONCLUSION

Compared with placebo, ensovibep did not improve clinical outcomes for hospitalized participants with COVID-19 receiving standard care, including remdesivir; no safety concerns were identified.

PRIMARY FUNDING SOURCE

National Institutes of Health.

Enabling personalized medicine in Europe by the European Commission's funding activities

Personalized medicine (PM) is an emerging approach to prevention, diagnosis, treatment and care. It helps to address the challenge of the aging of the population, an increase in chronic disease and increasing healthcare costs. The EU is developing policies to move toward PM. This is underpinned by a sustained and significant investment starting in 2010. So far, a total of €3.2 billion has been invested in PM research across the medical innovation cycle ‘from bench to bedside’. This investment has come from the research framework programs FP7 and Horizon 2020. About a third of the total investment has been made in the context of the Innovative Medicines Initiative, the largest public–private partnership in life sciences globally.

European Union research in support of environment and health: Building scientific evidence base for policy

Opinion polls show that the European Union citizens are increasingly concerned about the impact of environmental factors on their health. In order to respond and provide solid scientific evidence for the numerous policies related to the protection of human health and the environment managed at the Union level, the European Union made a substantial investment in research and innovation in the past two decades through its Framework Programmes for Research and Technological Development, including the current programme, Horizon 2020, which started in 2014. This policy review paper analysed the portfolio of forty collaborative projects relevant to environment and health, which received a total amount of around 228 million euros from the EU. It gives details on their contents and general scientific trends observed, the profiles of the participating countries and institutions, and the potential policy implications of the results obtained. The increasing knowledge base is needed to make informed policy decisions in Europe and beyond, and should be useful to many stakeholders including the scientific community and regulatory authorities.

European strategy for vaccine development against infectious diseases

Immunisation efforts save millions of lives every year, but vaccines hold the potential to deliver even greater health benefits for mankind. Vaccine research and development is highly complex, and it requires concerted public funding efforts to support. In this paper we discuss EU funding priorities and the resulting recent advancements in European vaccine research, and we lay out the EU strategy for aiding promising vaccine candidates to successfully reach the market.

Better safe than sorry: ethics review in European Union-funded health research

Public scrutiny and the increasing number of projects addressing later stages of the research and innovation process announced the need for an enhanced attention to be paid to identify and address ethics concerns. Ex-ante ethics review as implemented in EU-funded health research and a proactive ethics management are a genuinely useful exercise and ensures top-quality research, from the lab to the patient.

Toward an international initiative for traumatic brain injury research

The European Commission (EC) and the National Institutes of Health (NIH) jointly sponsored a workshop on October 18-20, 2011 in Brussels to discuss the feasibility and benefits of an international collaboration in the field of traumatic brain injury (TBI) research. The workshop brought together scientists, clinicians, patients, and industry representatives from around the globe as well as funding agencies from the EU, Spain, the United States, and Canada. Sessions tackled both the possible goals and governance of a future initiative and the scientific questions that would most benefit from an integrated international effort: how to optimize data collection and sharing; injury classification; outcome measures; clinical study design; and statistical analysis. There was a clear consensus that increased dialogue and coordination of research at an international level would be beneficial for advancing TBI research, treatment, and care. To this end, the EC, the NIH, and the Canadian Institutes of Health Research expressed interest in developing a framework for an international initiative for TBI Research (InTBIR). The workshop participants recommended that InTBIR initially focus on collecting, standardizing, and sharing clinical TBI data for comparative effectiveness research, which will ultimately result in better management and treatments for TBI.

Immunotherapy against HPV16/18 generates potent TH1 and cytotoxic cellular immune responses

Despite the development of highly effective prophylactic vaccines against human papillomavirus (HPV) serotypes 16 and 18, prevention of cervical dysplasia and cancer in women infected with high-risk HPV serotypes remains an unmet medical need. We report encouraging phase 1 safety, tolerability, and immunogenicity results for a therapeutic HPV16/18 candidate vaccine, VGX-3100, delivered by in vivo electroporation (EP). Eighteen women previously treated for cervical intraepithelial neoplasia grade 2 or 3 (CIN2/3) received a three-dose (intramuscular) regimen of highly engineered plasmid DNA encoding HPV16 and HPV18 E6/E7 antigens followed by EP in a dose escalation study (0.3, 1, and 3 mg per plasmid). Immunization was well tolerated with reports of mild injection site reactions and no study-related serious or grade 3 and 4 adverse events. No dose-limiting toxicity was noted, and pain was assessed by visual analog scale, with average scores decreasing from 6.2/10 to 1.4 within 10 min. Average peak interferon-γ enzyme-linked immunospot magnitudes were highest in the 3 mg cohort in comparison to the 0.3 and 1 mg cohorts, suggesting a trend toward a dose effect. Flow cytometric analysis revealed the induction of HPV-specific CD8(+) T cells that efficiently loaded granzyme B and perforin and exhibited full cytolytic functionality in all cohorts. These data indicate that VGX-3100 is capable of driving robust immune responses to antigens from high-risk HPV serotypes and could contribute to elimination of HPV-infected cells and subsequent regression of the dysplastic process.

Enabling personalized medicine in Europe: a look at the European Commission's funding activities in the field of personalized medicine research

The potential benefits that personalized medicine approaches can bring to healthcare are discussed with much interest throughout the EU. This novel approach is based on a better understanding of the molecular mechanisms of health and disease and it has now begun to show results. There is, however, a long way to go before the area is fully exploited. This special report reviews the European Commission's funding activities related to personalized medicine research. Although the specific focus on personalized medicine is relatively new, the European Commission has already committed significant funding to research in enabling technologies relevant to the field, as well as to specific disease areas for their application. A stocktaking exercise which started in 2010 has helped identify immediate and future challenges in personalized medicine research. The outcome of this exercise, summarized below, will contribute to developing a vision for future research funding at the EU level.

Emphasising the European Union's Commitment to Cancer Research: a helicopter view of the Seventh Framework Programme for Research and Technological Development

This article discusses the efforts undertaken in the European Union toward basic, translational, and clinical cancer research on prevention, early diagnosis, prognosis, treatment, cancer control, quality of life, and survivorship.

The selection of experts evaluating health projects for the EU Sixth Framework Program

Aim

The Framework Programmes for Research and Technological Development (FP) are the European Union’s funding programmes for research in Europe. The study analyses the features of external experts involved in evaluating the research proposals in FP6 (years 2003–2006) in the area of Life Sciences.

Subjects and methods

Experts were analysed with respect to nationality, gender, organisational affiliation and rotation. The correlations between the number of experts by nationality and scientific research indicators were also explored.

Result

Experts from 70 countries participated, with 70% coming from 10 countries. The gender composition was relatively stable, with approximately 30% of female experts. The majority of experts came from higher education establishments (51%) and 12% from industry. About 40% of experts participated in the evaluation process two or more times. The number of experts by nationality was linearly correlated with gross national income (r = 0.95, p < 0.0001), population (r = 0.91, p < 0.0001), and number of research publications in health sciences (r = 0.93, p < 0.0001). However, using multiple linear regression analysis, only gross national income had partial regression coefficients significantly different from zero (p = 0.017). The observed value of experts for Italy (312) and Belgium (155) were higher than predicted by this regression model (231 and 71 respectively).

Conclusion

The expert panels involved were balanced with respect to nationalities, whereas the gender distribution was lower than the target. There was a satisfactory degree of rotation of experts between evaluation rounds. The percentage of experts from industry was lower than expected.

Multivalent smallpox DNA vaccine delivered by intradermal electroporation drives protective immunity in nonhuman primates against lethal monkeypox challenge

The threat of a smallpox-based bioterrorist event or a human monkeypox outbreak has heightened the importance of new, safe vaccine approaches for these pathogens to complement older poxviral vaccine platforms. As poxviruses are large, complex viruses, they present technological challenges for simple recombinant vaccine development where a multicomponent mixtures of vaccine antigens are likely important in protection. We report that a synthetic, multivalent, highly concentrated, DNA vaccine delivered by a minimally invasive, novel skin electroporation microarray can drive polyvalent immunity in macaques, and offers protection from a highly pathogenic monkeypox challenge. Such a diverse, high-titer antibody response produced against 8 different DNA-encoded antigens delivered simultaneously in microvolumes has not been previously described. These studies represent a significant improvement in the efficiency of the DNA vaccine platform, resulting in immune responses that mimic live viral infections, and would likely have relevance for vaccine design against complex human and animal pathogens.

European Union vaccine research--an overview

Recent developments in vaccine research provide new momentum for an important area in health innovation. Particularly interesting are novel DNA vaccine approaches, many of which are already under clinical investigation. The Framework Programmes of the European Union play an important role in supporting collaborative efforts in vaccine research to develop new and better vaccines and bring them to the market. With a timely strategic reorientation towards a sustainable investment in innovation, the current seventh Framework Programme will help to bring large industry and small and medium-sized enterprises (SME) on board and foster partnership between stakeholders. As the first human DNA vaccines progresses through the development pipeline, more and more questions revolve around licensing and regulation and appropriate guidelines are being developed.

Systemic immunization with CCL27/CTACK modulates immune responses at mucosal sites in mice and macaques

Plasmid DNA is a promising vaccine platform that has been shown to be safe and able to be administered repeatedly without vector interference. Enhancing the potency of DNA vaccination through co-delivery of molecular adjuvants is one strategy currently under investigation. Here we describe the use of the novel chemokine adjuvant CCL27/CTACK to enhance immune responses to an HIV-1 or SIV antigen in mice and rhesus macaques. CCL27 has been shown to play a role in inflammatory responses through chemotaxis of CCR10+ cells, and we hypothesized that CCL27 may modulate adaptive immune responses. Immunizations in mice with HIV-1gag/CCL27 enhanced immune responses both at peripheral and, surprisingly, at mucosal sites. To confirm these findings in a large-animal model, we created optimized CCL27 and SIV antigenic plasmid constructs for rhesus macaques. 10 macaques (n=5/group) were immunized intramuscularly with 1mg/construct of antigenic plasmids+/-CCL27 with electroporation. We observed significant IFN-gamma secretion and CD8+ T-cell proliferation in peripheral blood. Interestingly, CCL27 co-immunized macaques exhibited a trend toward greater effector CD4+ T cells in the bronchiolar lavage (BAL). CCL27 co-delivery also elicited greater antigen-specific IgA at unique sites including BAL and fecal samples but not in the periphery. Future studies incorporating CCL27 as an adjuvant in vaccine or therapy models where eliciting immune responses in the lung are warranted.

Production of pharmaceutical-grade plasmids at high concentration and high supercoiled percentage

The increased use of plasmid-based vaccines to replace their more challenging viral counterparts has increased the demand for high purity and high concentration plasmids. Here we report the production of plasmids encoding different transgenes for DNA vaccine candidates at gram scale with an integrated process consisting of batch fermentation and limited steps of purification. Plasmid products encoding for eight smallpox antigens that were combined into a bioterrorism DNA vaccine exhibited high purity with undetectable RNA, protein and endotoxin, concentration of up to 13.6mg/mL and supercoiled percentage of 94.5+/-1.1% after storage at -80 degrees C for over 1 year. The process has been scaled up for the cGMP manufacture of pharmaceutical-grade human papillomavirus and influenza DNA vaccines up to a 50g scale, also demonstrating high purity and high concentration.

High dose of plasmid IL-15 inhibits immune responses in an influenza non-human primates immunogenicity model

Interleukin (IL)-15, is a cytokine that is important for the maintenance of long-lasting, high-avidity T cell response to invading pathogens and has, therefore, been used in vaccine and therapeutic platforms as an adjuvant. In addition to pure protein delivery, plasmids encoding the IL-15 gene have been utilized. However, it is critical to determine the appropriate dose to maximize the adjuvanting effects. We immunized rhesus macaques with different doses of IL-15 expressing plasmid in an influenza non-human primate immunogenicity model. We found that co-immunization of rhesus macaques with a Flu DNA-based vaccine and low doses of plasmid encoding macaque IL-15 enhanced the production of IFN-gamma (0.5 mg) and the proliferation of CD4(+) and CD8(+) T cells, as well as T(CM) levels in proliferating CD8(+) T cells (0.25 mg). Whereas, high doses of IL-15 (4 mg) decrease the production of IFN-gamma and the proliferation of CD4(+) and CD8(+) T cells and T(CM) levels in the proliferating CD4(+) and CD8(+) T cells. In addition, the data of hemagglutination inhibition (HI) antibody titer suggest that although not significantly different, there appears to be a slight increase in antibodies at lower doses of IL-15. Importantly, however, the higher doses of IL-15 decrease the antibody levels significantly. This study demonstrates the importance of optimizing DNA-based cytokine adjuvants.

Electroporation for the delivery of DNA-based vaccines and immunotherapeutics: current clinical developments

Electroporation (EP) has been used in basic research for the past 25 years to aid in the transfer of DNA into cells in vitro. EP in vivo enhances transfer of DNA vaccines and therapeutic plasmids to the skin, muscle, tumors, and other tissues resulting in high levels of expression, often with serological and clinical benefits. The recent interest in nonviral gene transfer as treatment options for a vast array of conditions has resulted in the refinement and optimization of EP technology. Current research has revealed that EP can be successfully used in many species, including humans. Clinical trials are currently under way. Herein, the transition of EP from basic science to clinical trials will be discussed.

Intramuscular delivery of a plasmid-encoded molecular adjuvant elicits immune responses at mucosal sites in a macaque model (39.51)

As the primary site of HIV-1 replication is the mucosa, a desirable feature of a HIV-1 vaccine would be the generation of immune responses at mucosal sites. We created an optimized CCL27 DNA construct as well as optimized SIV gag, pol, and env plasmids for immunizing rhesus macaques. Macaques (n=5/group) were immunized with SIV plasmids +/- CCL27. Both immunization groups had significant IFN-g responses against the encoded SIV antigens (~12,000 SFU/106 PBMCs). CD8+ T cell proliferation as measured by CFSE staining was similar between the groups at ~22%. While systemic immune responses were robust, co-delivery of CCL27 did not adjuvant peripheral responses similar to what was observed in mice. Interestingly, macaques that received CCL27 had greater antigen specific IgA at mucosal sites including bronchial lavage and fecal samples. In addition, CD4+ T cells secreting effector cytokines were enhanced in the CCL27 group at mucosal, but not peripheral sites when compared to the antigenic group alone. The CCL27 group also had more polyfunctional CD8+ T cells in the bronchial lavage than the DNA group post-challenge. These data show that a novel chemokine adjuvant may be capable of targeting immune responses to mucosal sites. This strategy may also be applicable to other diseases than HIV-1 where mucosal immune responses are desirable.

In vivo electroporation of gene sequences for therapeutic and vaccination applications

Many recent studies have addressed the impact of gene patents and methods of gene delivery on downstream research and innovation. The field of gene therapy has progressed over the last 10 years due to the rapid advancement in delivery technology. Efficient delivery of genes into target cells depends on the absence of cell injury, oncogenic mutation or inflammation. Gene transfer technology saw a significant boost by the applications of in vivo electroporation. This approach is versatile and safe and can be used to deliver nucleic acid fragments, oligonucleotides, siRNA, and plasmids to a wide variety of tissues, such as skeletal muscle, skin and liver. Many have applied this approach in autoimmune or inflammatory diseases, for the intratumoral delivery of therapeutic vectors, or for systemic delivery of endocrine hormones, hematopoietic factors, antibodies, enzymes, or numerous other protein drugs. This technique has been found to strongly boost DNA vaccination against infectious agents or tumor antigens. in vivo Electroporation has been performed in humans. This review will focus on the intellectual property revolving around recent developments in the area of electroporation, including devices and methodology for various applications.

Gene therapy by electroporation for the treatment of chronic renal failure in companion animals

Background

Growth hormone-releasing hormone (GHRH) plasmid-based therapy for the treatment of chronic renal failure and its complications was examined. Companion dogs (13.1 ± 0.8 years, 29.4 ± 5.01 kg) and cats (13.2 ± 0.9 years, 8.5 ± 0.37 kg) received a single 0.4 mg or 0.1 mg species-specific plasmid injection, respectively, intramuscularly followed by electroporation, and analyzed up to 75 days post-treatment; controls underwent electroporation without plasmid administration.

Results

Plasmid-treated animals showed an increase in body weight (dogs 22.5% and cats 3.2%) compared to control animals, and displayed improved quality of life parameters including significant increases in appetite, activity, mentation and exercise tolerance levels. Insulin-like growth factor I (IGF-I, the downstream effector of GHRH) levels were increased in the plasmid treated animals. Hematological parameters were also significantly improved. Protein metabolism changes were observed suggesting a shift from a catabolic to an anabolic state in the treated animals. Blood urea nitrogen and creatinine did not show any significant changes suggesting maintenance of kidney function whereas the control animal's renal function deteriorated. Treated animals survived longer than control animals with 70% of dogs and 80% of cats surviving until study day 75. Only 17% and 40% of the control dogs and cats, respectively, survived to day 75.

Conclusion

Improved quality of life, survival and general well-being indicate that further investigation is warranted, and show the potential of a plasmid-based therapy by electroporation in preventing and managing complications of renal insufficiency.

Effects of plasmid growth hormone-releasing hormone treatment during heat stress

A gene therapy treatment with plasmid-based growth hormone-releasing hormone (GHRH) delivered by electroporation (EP) was investigated during heat stress; 32 primiparous cows received 2.5 mg of a GHRH-expressing myogenic plasmid (pSP-HV-GHRH), while 20 were designated as controls. Offspring of treated animals showed a reduction in mortality (47%; p < 0.02), and survival from birth to 260 days was dramatically improved (0% mortality vs. 21% in controls) along with an increase in weight gain (p < 0.05). Milk production was increased compared to controls with an average yield gain of 421 kg/cow (p = 0.028). Prolactin (PRL) levels were also significantly increased compared to controls (p < 0.05). The second pregnancy rate was improved by GHRH treatment (53.3% vs. 30.8%). This study shows that the use of plasmid-mediated therapy delivered by EP can maintain health status during periods of heat stress, important for both animals and potentially humans in hot, challenging climates.

Plasmid growth hormone releasing hormone therapy in healthy and laminitis-afflicted horses-evaluation and pilot study

BACKGROUND

In vivo electroporation dramatically improves the potency of plasmid-mediated therapies, including in large animal models. Laminitis and arthritis are common and debilitating diseases in the horse, as well as humans.

METHODS

The effects of growth hormone releasing hormone (GHRH) on healthy horses and on horses with laminitis that were followed for 6 months after a single intramuscular injection and electroporation of 2.5 mg of an optimized myogenic GHRH-expressing plasmid were examined.

RESULTS

In the first study on six healthy horses, we observed a significant increase in body mass by day 180 compared to baseline (P < 0.003), and an increase in erythrocyte production (hematocrit, red blood cells, hemoglobin, P = 0.03). IGF-I levels were increased by 7% by day 120 (P = 0.02). A pilot study was performed on two horses with chronic laminitis, a vascular condition often associated with arthritis, with two horses with similar clinical disease serving as non-treated controls. Treated horses experienced an increase in weight compared to control horses that received standard care (P = 0.007). By 6 months post-treatment, treated subjects were rated pasture sound. Physical and radiographic evaluation demonstrated significant improvement with reduced inflammation and decreased lameness.

CONCLUSIONS

These results demonstrate that a plasmid therapy delivered by electroporation can potentially be used to treat chronic conditions in horses, and possibly other very large mammals. While further studies are needed, overall this proof-of-concept work presents encouraging data for studying gene therapeutic treatments for Raynaud's syndrome and arthritis in humans.

Strong HCV NS3- and NS4A-specific cellular immune responses induced in mice and Rhesus macaques by a novel HCV genotype 1a/1b consensus DNA vaccine

Hepatitis C virus (HCV) represents a major health burden with more than 170 million individuals currently infected worldwide, equaling roughly 3% of the world's population. HCV preferentially infects hepatocytes and is able to persist in up to 70% of infected individuals. It is estimated that up to 30% of chronically infected individuals will go on to develop progressive liver disease as a result of HCV infection, making the virus the leading cause of liver transplantation in the world. Currently there is no vaccine for HCV. In this study, we have taken a multi-step approach to develop a novel genotype 1a/1b consensus HCV NS3/NS4A DNA vaccine able to induce strong cellular immunity. We show that this construct is able to induce strong anti-NS3/NS4A T cell responses in C57BL/6 mice, as well as, in Rhesus macaques. Our data suggest that DNA vaccines encoding HCV proteins NS3/NS4A merit further study in the context of future prophylactic and therapeutic HCV T cell based vaccines.

Heterosubtypic protection against pathogenic human and avian influenza viruses via in vivo electroporation of synthetic consensus DNA antigens

Background

The persistent evolution of highly pathogenic avian influenza (HPAI) highlights the need for novel vaccination techniques that can quickly and effectively respond to emerging viral threats. We evaluated the use of optimized consensus influenza antigens to provide broad protection against divergent strains of H5N1 influenza in three animal models of mice, ferrets, and non-human primates. We also evaluated the use of in vivo electroporation to deliver these vaccines to overcome the immunogenicity barrier encountered in larger animal models of vaccination.

Methods and Findings

Mice, ferrets and non-human primates were immunized with consensus plasmids expressing H5 hemagglutinin (pH5HA), N1 neuraminidase (pN1NA), and nucleoprotein antigen (pNP). Dramatic IFN-γ-based cellular immune responses to both H5 and NP, largely dependent upon CD8+ T cells were seen in mice. Hemaggutination inhibition titers classically associated with protection (>1:40) were seen in all species. Responses in both ferrets and macaques demonstrate the ability of synthetic consensus antigens to induce antibodies capable of inhibiting divergent strains of the H5N1 subtype, and studies in the mouse and ferret demonstrate the ability of synthetic consensus vaccines to induce protection even in the absence of such neutralizing antibodies. After challenge, protection from morbidity and mortality was seen in mice and ferrets, with significant reductions in viral shedding and disease progression seen in vaccinated animals.

Conclusions

By combining several consensus influenza antigens with in vivo electroporation, we demonstrate that these antigens induce both protective cellular and humoral immune responses in mice, ferrets and non-human primates. We also demonstrate the ability of these antigens to protect from both morbidity and mortality in a ferret model of HPAI, in both the presence and absence of neutralizing antibody, which will be critical in responding to the antigenic drift that will likely occur before these viruses cross the species barrier to humans.

Muscle and fat mass modulation in different clinical models

Studies described in the recent literature support the idea that gene therapy can lead to genuine clinical benefits when mediated by plasmid delivery in conjunction with electroporation. Plasmid-mediated muscle-targeted gene transfer offers the potential of a cost-effective pharmaceutical-grade therapy delivered by simple intramuscular injection. This approach is particularly appropriate for modulating muscle and fat mass and their intrinsic properties, from treatment of conditions such as cachexia associated with chronic diseases, autoimmune diseases, e.g., myasthenia gravis, to stimulation or suppression of appetite, and further to in vivo manipulation of glucose metabolism and fat deposition in patients with diabetes, or to basic studies of muscle-specific transcription factors and their impact in development. Recent innovations, including in situ electroporation, enabling sustained systemic protein delivery within the therapeutic range, are reviewed. Translation of these advances to human clinical trials will enable muscle- and fat-targeted gene therapy to become a viable therapeutic alternative.

Increased immune responses in rhesus macaques by DNA vaccination combined with electroporation

We used optimized DNA expression vectors to compare two gene delivery methodologies in rhesus macaques, namely direct DNA injection and in vivo adaptive constant-current electroporation via the intramuscular route. The use of in vivo electroporation increased levels of gene expression and immune responses. We used an optimized HIV gag expression plasmid to show the development of new cellular immune responses in SIV-infected animals controlling viremia. Furthermore, after vaccination with SIV expression plasmids the recall responses to the SIV antigens were very high, indicating that DNA is a strong boost in the presence of antiretroviral treatment in SIV-infected animals. There was substantial animal-to-animal variability in DNA expression, revealed by plasma measurements of IL-15 produced by co-injected IL-15 DNA. IL-15 expression levels correlated with peak immune responses. Electroporation led to an expansion of antigen-specific CD4+ and CD8+ T cells of both central and effector memory phenotype. These results indicate that improved gene delivery and expression by electroporation dramatically increases immunogenicity of DNA vaccines. Electroporation is thus an important method to improve the effectiveness of DNA vaccination.