Superior efficacy of a skin-applied microprojection device for delivering a novel Zika DNA vaccine.

Zika virus (ZIKV) infections are spreading silently with limited global surveillance in at least 89 countries and territories. There is a pressing need to develop an effective vaccine suitable for equitable distribution globally. Consequently, we previously developed a proprietary DNA vaccine encoding secreted non-structural protein 1 of ZIKV (pVAX-tpaNS1) to elicit rapid protection in a T cell-dependent manner in mice.

Enhanced T Cell Responses Induced by a Necrotic Dendritic Cell Vaccine, Expressing HCV NS3.

A vaccine that induces potent, broad and sustained cell-mediated immunity, resulting in effective memory has the potential to restrict hepatitis C (HCV) virus infection. Early, multi-functional CD4 and CD8 T cell responses against non-structural protein 3 (NS3) have been associated with HCV clearance. Necrotic cells generate strong immune responses and represent a major antigenic source used by dendritic cells (DC) for processing and presentation, but there is conflicting evidence as to their immunogenicity in vaccination.

Structural and functional characterization of C0021158, a high-affinity monoclonal antibody that inhibits Arginase 2 function via a novel non-competitive mechanism of action.

Arginase 2 (ARG2) is a binuclear manganese metalloenzyme that catalyzes the hydrolysis of L-arginine. The dysregulated expression of ARG2 within specific tumor microenvironments generates an immunosuppressive niche that effectively renders the tumor 'invisible' to the host's immune system. Increased ARG2 expression leads to a concomitant depletion of local L-arginine levels, which in turn leads to suppression of anti-tumor T-cell-mediated immune responses.

Extensive sequence and structural evolution of Arginase 2 inhibitory antibodies enabled by an unbiased approach to affinity maturation.

Affinity maturation is a powerful technique in antibody engineering for the in vitro evolution of antigen binding interactions. Key to the success of this process is the expansion of sequence and combinatorial diversity to increase the structural repertoire from which superior binding variants may be selected. However, conventional strategies are often restrictive and only focus on small regions of the antibody at a time.

Safety Profile of a Multi-Antigenic DNA Vaccine Against Hepatitis C Virus.

Despite direct acting antivirals (DAAs) curing >95% of individuals infected with hepatitis C (HCV), in order to achieve the World Health Organization HCV Global Elimination Goals by 2030 there are still major challenges that need to be overcome. DAAs alone are unlikely to eliminate HCV in the absence of a vaccine that can limit viral transmission. Consequently, a prophylactic HCV vaccine is necessary to relieve the worldwide burden of HCV disease.

NS1 DNA vaccination protects against Zika infection through T cell-mediated immunity in immunocompetent mice.

The causal association of Zika virus (ZIKV) with microcephaly, congenital malformations in infants, and Guillain-Barré syndrome in adults highlights the need for effective vaccines. Thus far, efforts to develop ZIKV vaccines have focused on the viral envelope. ZIKV NS1 as a vaccine immunogen has not been fully explored, although it can circumvent the risk of antibody-dependent enhancement of ZIKV infection, associated with envelope antibodies.

Single-Dose Vaccination with a Hepatotropic Adeno-associated Virus Efficiently Localizes T Cell Immunity in the Liver with the Potential To Confer Rapid Protection against Hepatitis C Virus.

Hepatitis C virus (HCV) is a significant contributor to the global disease burden, and development of an effective vaccine is required to eliminate HCV infections worldwide. CD4 and CD8 T cell immunity correlates with viral clearance in primary HCV infection, and intrahepatic CD8 tissue-resident memory T (T) cells provide lifelong and rapid protection against hepatotropic pathogens. Consequently, we aimed to develop a vaccine to elicit HCV-specific CD4 and CD8 T cells, including CD8 T cells, in the liver, given that HCV primarily infects hepatocytes.

Pre-clinical evaluation of a quadrivalent HCV VLP vaccine in pigs following microneedle delivery.

The introduction of directly acting antiviral agents (DAAs) has produced significant improvements in the ability to cure chronic hepatitis C infection. However, with over 2% of the world's population infected with HCV, complications arising from the development of cirrhosis of the liver, chronic hepatitis C infection remains the leading indication for liver transplantation. Several modelling studies have indicated that DAAs alone will not be sufficient to eliminate HCV, but if combined with an effective vaccine this regimen would provide a significant advance towards achieving this critical World Health Organisation goal.

A Hepatitis C Virus DNA Vaccine Encoding a Secreted, Oligomerized Form of Envelope Proteins Is Highly Immunogenic and Elicits Neutralizing Antibodies in Vaccinated Mice.

Hepatitis C virus (HCV) persistently infects approximately 71 million people globally. To prevent infection a vaccine which elicits neutralizing antibodies against the virus envelope proteins (E1/E2) which are required for entry into host cells is desirable. DNA vaccines are cost-effective to manufacture globally and despite recent landmark studies highlighting the therapeutic efficacy of DNA vaccines in humans against cervical cancer, DNA vaccines encoding E1/E2 developed thus far are poorly immunogenic.

Cytolytic Perforin as an Adjuvant to Enhance the Immunogenicity of DNA Vaccines.

DNA vaccines present one of the most cost-effective platforms to develop global vaccines, which have been tested for nearly three decades in preclinical and clinical settings with some success in the clinic. However, one of the major challenges for the development of DNA vaccines is their poor immunogenicity in humans, which has led to refinements in DNA delivery, dosage in prime/boost regimens and the inclusion of adjuvants to enhance their immunogenicity. In this review, we focus on adjuvants that can enhance the immunogenicity of DNA encoded antigens and highlight the development of a novel cytolytic DNA platform encoding a truncated mouse perforin.

Toward DNA-Based T-Cell Mediated Vaccines to Target HIV-1 and Hepatitis C Virus: Approaches to Elicit Localized Immunity for Protection.

Human immunodeficiency virus (HIV)-1 and hepatitis C virus (HCV) are major contributors to the global disease burden with many experts recognizing the requirement of an effective vaccine to bring a durable end to these viral epidemics. The most promising vaccine candidates that have advanced into pre-clinical models and the clinic to eliminate or provide protection against these chronic viruses are viral vectors [e.g.

Viral vector and route of administration determine the ILC and DC profiles responsible for downstream vaccine-specific immune outcomes.

This study demonstrates that route and viral vector can significantly influence the innate lymphoid cells (ILC) and dendritic cells (DC) recruited to the vaccination site, 24 h post delivery. Intranasal (i.n.

Immunological responses following administration of a genotype 1a/1b/2/3a quadrivalent HCV VLP vaccine.

The significant public health problem of Hepatitis C virus (HCV) has been partially addressed with the advent of directly acting antiviral agents (DAAs). However, the development of an effective preventative vaccine would have a significant impact on HCV incidence and would represent a major advance towards controlling and possibly eradicating HCV globally. We previously reported a genotype 1a HCV viral-like particle (VLP) vaccine that produced neutralizing antibodies (NAb) and T cell responses to HCV.

Antibody Responses to a Quadrivalent Hepatitis C Viral-Like Particle Vaccine Adjuvanted with Toll-Like Receptor 2 Agonists.

The development of an effective preventative hepatitis C virus (HCV) vaccine will reside, in part, in its ability to elicit neutralizing antibodies (NAbs). We previously reported a genotype 1a HCV virus like particle (VLP) vaccine that produced HCV specific NAb and T cell responses that were substantially enhanced by Toll-like receptor 2 (TLR2) agonists. We have now produced a quadrivalent genotype 1a/1b/2a/3a HCV VLP vaccine and tested the ability of two TLR2 agonists, RPamCys and EPamCys, to stimulate the production of NAb.

Induction of Genotype Cross-Reactive, Hepatitis C Virus-Specific, Cell-Mediated Immunity in DNA-Vaccinated Mice.

A universal hepatitis C virus (HCV) vaccine should elicit multiantigenic, multigenotypic responses, which are more likely to protect against challenge with the range of genotypes and subtypes circulating in the community. A vaccine cocktail and vaccines encoding consensus HCV sequences are attractive approaches to achieve this goal. Consequently, in a series of mouse vaccination studies, we compared the immunogenicity of a DNA vaccine encoding a consensus HCV nonstructural 5B (NS5B) protein to that of a cocktail of DNA plasmids encoding the genotype 1b (Gt1b) and Gt3a NS5B proteins.

Preclinical Development and Production of Virus-Like Particles As Vaccine Candidates for Hepatitis C.

Hepatitis C Virus (HCV) infects 2% of the world's population and is the leading cause of liver disease and liver transplantation. It poses a serious and growing worldwide public health problem that will only be partially addressed with the introduction of new antiviral therapies. However, these treatments will not prevent re-infection particularly in high risk populations.

Emerging Targets for Developing T Cell-Mediated Vaccines for Human Immunodeficiency Virus (HIV)-1.

Human immunodeficiency virus (HIV)-1 has infected >75 million individuals globally, and, according to the UN, is responsible for ~2.1 million new infections and 1.1 million deaths each year.

Cytolytic DNA vaccine encoding lytic perforin augments the maturation of- and antigen presentation by- dendritic cells in a time-dependent manner.

The use of cost-effective vaccines capable of inducing robust CD8 T cell immunity will contribute significantly towards the elimination of persistent viral infections and cancers worldwide. We have previously reported that a cytolytic DNA vaccine encoding an immunogen and a truncated mouse perforin (PRF) protein significantly augments anti-viral T cell (including CD8 T cell) immunity. Thus, the current study investigated whether this vaccine enhances activation of dendritic cells (DCs) resulting in greater priming of CD8 T cell immunity.

Human Rhinovirus-A1 as an Expression Vector.

Expression vectors that are based on live human rhinoviruses (HRVs) are attractive, yet often overlooked in vaccine development due to their limited capacity for foreign gene inserts and poor genetic stability. This chapter describes a novel methodology to engineer a replication-competent genetically stable recombinant HRV (rHRV) without affecting viral replication capability. We have previously used these methods to generate live, genetically stable recombinant HRVs encoding HIV Gag and Tat proteins (rHRV-Gag-Tat), a potential mucosally targeted HIV vaccine.

Mucosal vaccination with a live recombinant rhinovirus followed by intradermal DNA administration elicits potent and protective HIV-specific immune responses.

Mucosal immunity is deemed crucial to control sexual transmission of human immunodeficiency virus (HIV). Herein we report the efficacy of a mucosal HIV vaccine strategy comprising intranasal (IN) vaccination with a cocktail of live recombinant human rhinoviruses (HRVs) encoding overlapping fragments of HIV Gag and full length Tat (rHRV-Gag/Tat) followed by intradermal (ID) vaccination with DNA vaccines encoding HIV Gag and Tat (pVAX-Gag-Tat). This heterologous prime-boost strategy will be referred to hereafter as rHRV-DNA.

Delivery methods to increase cellular uptake and immunogenicity of DNA vaccines.

DNA vaccines are ideal candidates for global vaccination purposes because they are inexpensive and easy to manufacture on a large scale such that even people living in low-income countries can benefit from vaccination. However, the potential of DNA vaccines has not been realized owing mainly to the poor cellular uptake of DNA in vivo resulting in the poor immunogenicity of DNA vaccines. In this review, we discuss the benefits and shortcomings of several promising and innovative non-biological methods of DNA delivery that can be used to increase cellular delivery and efficacy of DNA vaccines.

Large scale production of a mammalian cell derived quadrivalent hepatitis C virus like particle vaccine.

A method for the large-scale production of a quadrivalent mammalian cell derived hepatitis C virus-like particles (HCV VLPs) is described. The HCV core E1 and E2 coding sequences of genotype 1a, 1b, 2a or 3a were co-expressed in Huh7 cell factories using a recombinant adenoviral expression system. The structural proteins self-assembled into VLPs that were purified from Huh7 cell lysates by iodixanol ultracentrifugation and Stirred cell ultrafiltration.

A HIV-Tat/C4-binding protein chimera encoded by a DNA vaccine is highly immunogenic and contains acute EcoHIV infection in mice.

DNA vaccines are cost-effective to manufacture on a global scale and Tat-based DNA vaccines have yielded protective outcomes in preclinical and clinical models of human immunodeficiency virus (HIV), highlighting the potential of such vaccines. However, Tat-based DNA vaccines have been poorly immunogenic, and despite the administration of multiple doses and/or the addition of adjuvants, these vaccines are not in general use. In this study, we improved Tat immunogenicity by fusing it with the oligomerisation domain of a chimeric C4-binding protein (C4b-p), termed IMX313, resulting in Tat heptamerisation and linked Tat to the leader sequence of tissue plasminogen activator (TPA) to ensure that the bulk of heptamerised Tat is secreted.