Intranasal vaccination with a Newcastle disease virus-vectored vaccine protects hamsters from SARS-CoV-2 infection and disease

Intranasal vaccination with an NDV-vectored SARS-CoV-2 vaccine protects against Delta and Omicron challenges

The rapid development and deployment of vaccines following the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been estimated to have saved millions of lives. Despite their immense success, there remains a need for next-generation vaccination approaches for SARS-CoV-2 and future emerging coronaviruses and other respiratory viruses. Here we utilized a Newcastle Disease virus (NDV) vectored vaccine expressing the ancestral SARS-CoV-2 spike protein in a pre-fusion stabilized chimeric conformation (NDV-PFS). When delivered intranasally, NDV-PFS protected both Syrian hamsters and K18 mice against Delta and Omicron SARS-CoV-2 variants of concern. Additionally, intranasal vaccination induced robust, durable protection that was extended to 6 months post-vaccination. Overall, our data provide evidence that NDV-vectored vaccines represent a viable next-generation mucosal vaccination approach.

Mucosal Vaccination with a Newcastle Disease Virus-Vectored Vaccine Reduces Viral Loads in SARS-CoV-2-Infected Cynomolgus Macaques

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged following an outbreak of unexplained viral illness in China in late 2019. Since then, it has spread globally causing a pandemic that has resulted in millions of deaths and has had enormous economic and social consequences. The emergence of SARS-CoV-2 saw the rapid and widespread development of a number of vaccine candidates worldwide, and this never-before-seen pace of vaccine development led to several candidates progressing immediately through clinical trials. Many countries have now approved vaccines for emergency use, with large-scale vaccination programs ongoing. Despite these successes, there remains a need for ongoing pre-clinical and clinical development of vaccine candidates against SARS-CoV-2, as well as vaccines that can elicit strong mucosal immune responses. Here, we report on the efficacy of a Newcastle disease virus-vectored vaccine candidate expressing SARS-CoV-2 spike protein (NDV-FLS) administered to cynomolgus macaques. Macaques given two doses of the vaccine via respiratory immunization developed robust immune responses and had reduced viral RNA levels in nasal swabs and in the lower airway. Our data indicate that NDV-FLS administered mucosally provides significant protection against SARS-CoV-2 infection, resulting in reduced viral burden and disease manifestation, and should be considered as a viable candidate for clinical development.

The protective effect of intranasal immunization with influenza virus recombinant adenovirus vaccine on mucosal and systemic immune response

Influenza virus is a kind of virus that poses several hazards of animal and human health. Therefore, it is important to develop an effective vaccine to prevent influenza. To this end we successfully packaged recombinant adenovirus rAd-NP-M2e-GFP expressing multiple copies of influenza virus conserved antigens NP and M2e and packaged empty vector adenovirus rAd-GFP. The effect of rAd-NP-M2e-GFP on the activation of dendritic cell (DC) in vitro and in vivo was detected by intranasal immunization. The results showed that rAd-NP-M2e-GFP promoted the activation of DC in vitro and in vivo. After the primary immunization and booster immunization of mice through the nasal immune way, the results showed that rAd-NP-M2e-GFP induced enhanced local mucosal-specific T cell responses, increased the content of SIgA in broncho alveolar lavage fluids (BALF) and triggered the differentiation of B cells in the germinal center. It is proved that rAd-NP-M2e-GFP can significantly elicit mucosal immunity and systemic immune response. In addition, rAd-NP-M2e-GFP could effectively protect mice after H1N1 influenza virus challenge. To lay the foundation and provide reference for further development of influenza virus mucosal vaccine in the future.

Newcastle Disease Virus (NDV)-based vaccine candidate against SARS-CoV-2 Omicron by intranasal immunization

Despite global vaccination efforts, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to evolve and spread globally. Currently, the development of affordable vaccine against Omicron variant of concern (VOC) is necessary. Here, we assessed the safety and immunogenicity of a SARS-CoV-2 vaccine consisting of a live Newcastle disease virus vector expressing the spike (S) protein of Omicron BA.1 administrated intranasally (IN) or intramuscularly (IM) in Golden Syrian hamster model. Immunogenicity studies showed that the prime-boost regimen elicited high antibody titers and the modified S antigen (Sm-F) could induce robust antibody response in low dosage immunization through IN route. Sera of the immunized hamsters provided effective cross-neutralizing activity against different Omicron variants, the prototype and delta strains of SARS-CoV-2. Moreover, the vaccine could provide complete immunoprotection in hamsters against the Omicron BA.1 challenge by either intranasal or intramuscular immunization. Overall, our study provides an alternative nasal vaccine against the SARS-CoV-2 Omicron variants.

A Comprehensive review on Pharmacokinetic Studies of Vaccines: Impact of delivery route, carrier-and its modulation on immune response

The lack of knowledge about the absorption, distribution, metabolism, and excretion (ADME) of vaccines makes former biopharmaceutical optimization difficult. This was shown during the COVID-19 immunization campaign, where gradual booster doses were introduced.. Thus, understanding vaccine ADME and its effects on immunization effectiveness could result in a more logical vaccine design in terms of formulation, method of administration, and dosing regimens. Herein, we will cover the information available on vaccine pharmacokinetics, impacts of delivery routes and carriers on ADME, utilization and efficiency of nanoparticulate delivery vehicles, impact of dose level and dosing schedule on the therapeutic efficacy of vaccines, intracellular and endosomal trafficking and in vivo fate, perspective on DNA and mRNA vaccines, new generation sequencing and mathematical models to improve cancer vaccination and pharmacology, and the reported toxicological study of COVID-19 vaccines. Altogether, this review will enhance the reader's understanding of the pharmacokinetics of vaccines and methods that can be implied in delivery vehicle design to improve the absorption and distribution of immunizing agents and estimate the appropriate dose to achieve better immunogenic responses and prevent toxicities.

Advantages and challenges of Newcastle disease virus as a vector for respiratory mucosal vaccines

Newcastle disease virus (NDV) is an avian pathogen with an unsegmented negative-strand RNA genome. Properties such as the ease of genome modification, respiratory tract tropism, and self-limiting replication in mammals make NDV an attractive vector for vaccine development. Experimental NDV-based vaccines against multiple human and animal pathogens elicited both systemic and mucosal immune responses and were protective in preclinical animal studies, but their real-life efficacy remains to be demonstrated. Only recently, the first results of clinical trials of NDV-based vaccines against SARS-CoV-2 became available, highlighting the challenges that need to be overcome to fully realize the potential of NDV as a platform for the rapid development of economically affordable and effective mucosal vaccines.

Multiplex flow cytometry-based assay for quantifying tumor- and virus-associated antibodies induced by immunotherapies

Novel immunotherapies continue to be developed and tested for application against a plethora of diseases. The clinical translation of immunotherapies requires an understanding of their mechanisms. The contributions of antibodies in driving long-term responses following immunotherapies continue to be revealed given their diverse effector functions. Developing an in-depth understanding of the role of antibodies in treatment efficacy is required to optimize immunotherapies and improve the chance of successfully translating them into the clinic. However, analyses of antibody responses can be challenging in the context of antigen-agnostic immunotherapies, particularly in the context of cancers that lack pre-defined target antigens. As such, robust methods are needed to evaluate the capacity of a given immunotherapy to induce beneficial antibody responses, and to identify any therapy-limiting antibodies. We previously developed a comprehensive method for detecting antibody responses induced by antigen-agnostic immunotherapies for application in pre-clinical models of vaccinology and cancer therapy. Here, we extend this method to a high-throughput, flow cytometry-based assay able to identify and quantify isotype-specific virus- and tumor-associated antibody responses induced by immunotherapies using small sample volumes with rapid speed and high sensitivity. This method provides a valuable and flexible protocol for investigating antibody responses induced by immunotherapies, which researchers can use to expand their analyses and optimize their own treatment regimens.

Intranasal administration of a live-attenuated recombinant newcastle disease virus expressing the SARS-CoV-2 Spike protein induces high neutralizing antibody levels and protects from experimental challenge infection in hamsters

The emergence of SARS-CoV-2 in December 2019 resulted in the COVID-19 pandemic. Recurring disease outbreaks repeatedly overloaded the public health sector and severely affected the global economy. We developed a candidate COVID-19 vaccine based on a recombinant Newcastle disease virus (NDV) vaccine vector, encoding a pre-fusion stabilized full-length Spike protein obtained from the original SARS-CoV-2 Wuhan isolate. Vaccination of hamsters by intra-muscular injection or intra-nasal instillation induced high neutralizing antibody responses. Intranasal challenge infection with SARS-CoV-2 strain Lelystad demonstrated that both vaccination routes provided partial protection in the upper respiratory tract, and almost complete protection in the lower respiratory tract, as measured by suppressed viral loads and absence of histological lung lesions. Activity wheel measurements demonstrated that animals vaccinated by intranasal inoculation rapidly recovered to normal activity. NDV constructs encoding the spike of SARS-CoV-2 may be attractive candidates for development of intra-nasal COVID-19 booster vaccines.

Single Immunization with Recombinant ACAM2000 Vaccinia Viruses Expressing the Spike and the Nucleocapsid Proteins Protects Hamsters against SARS-CoV-2-Caused Clinical Disease

Increasing cases of SARS-CoV-2 breakthrough infections from immunization with current spike protein-based COVID-19 vaccines highlight the need to develop alternative vaccines using different platforms and/or antigens. In this study, we expressed SARS-CoV-2 spike and nucleocapsid proteins based on a novel vaccinia virus (VACV) ACAM2000 platform (rACAM2000). In this platform, the vaccinia virus host range and immunoregulatory gene E3L was deleted to make the virus attenuated and to enhance innate immune responses, and another host range gene, K3L, was replaced with a poxvirus ortholog gene, taterapox virus 037 (TATV037), to make virus replication competent in both hamster and human cells. Following a single intramuscular immunization, the rACAM2000 coexpressing the spike and nucleocapsid proteins induced significantly improved protection against SARS-CoV-2 challenge in comparison to rACAM2000 expressing the individual proteins in a hamster model, as shown by reduced weight loss and shorter recovery time. The protection was associated with reduced viral loads, increased neutralizing antibody titer, and reduced neutrophil-to-lymphocyte ratio. Thus, our study demonstrates that rACAM2000 expressing a combination of the spike and nucleocapsid antigens is a promising COVID-19 vaccine candidate, and further studies will investigate if the rACAM2000 vaccine candidate can induce a long-lasting immunity against infection by SARS-CoV-2 variants of concern. IMPORTANCE Continuous emergence of SARS-CoV-2 variants which cause breakthrough infection from the immunity induced by current spike protein-based COVID-19 vaccines highlights the need for new generations of vaccines that will induce long-lasting immunity against a wide range of the variants. To this end, we investigated the protective efficacy of the recombinant COVID-19 vaccine candidates based on a novel VACV ACAM2000 platform, in which an immunoregulatory gene, E3L, was deleted and both the SARS-CoV-2 spike (S) and nucleocapsid (N) antigens were expressed. Thus, it is expected that the vaccine candidate we constructed should be more immunogenic and safer. In the initial study described in this work, we demonstrated that the vaccine candidate expressing both the S and N proteins is superior to the constructs expressing an individual protein (S or N) in protecting hamsters against SARS-CoV-2 challenge after a single-dose immunization, and further investigation against different SARS-CoV-2 variants will warrant future clinical evaluations.

Development and Scalable Production of Newcastle Disease Virus-Vectored Vaccines for Human and Veterinary Use

The COVID-19 pandemic has highlighted the need for efficient vaccine platforms that can rapidly be developed and manufactured on a large scale to immunize the population against emerging viruses. Viral-vectored vaccines are prominent vaccine platforms that have been approved for use against the Ebola virus and SARS-CoV-2. The Newcastle Disease Virus is a promising viral vector, as an avian paramyxovirus that infects poultry but is safe for use in humans and other animals. NDV has been extensively studied not only as an oncolytic virus but also a vector for human and veterinary vaccines, with currently ongoing clinical trials for use against SARS-CoV-2. However, there is a gap in NDV research when it comes to process development and scalable manufacturing, which are critical for future approved vaccines. In this review, we summarize the advantages of NDV as a viral vector, describe the steps and limitations to generating recombinant NDV constructs, review the advances in human and veterinary vaccine candidates in pre-clinical and clinical tests, and elaborate on production in embryonated chicken eggs and cell culture. Mainly, we discuss the existing data on NDV propagation from a process development perspective and provide prospects for the next steps necessary to potentially achieve large-scale NDV-vectored vaccine manufacturing.

Intranasal COVID-19 vaccines: From bench to bed

Currently licensed COVID-19 vaccines are all designed for intramuscular (IM) immunization. However, vaccination today failed to prevent the virus infection through the upper respiratory tract, which is partially due to the absence of mucosal immunity activation. Despite the emerging severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants, the next generation of COVID-19 vaccine is in demand and intranasal (IN) vaccination method has been demonstrated to be potent in inducing both mucosal and systemic immune responses. Presently, although not licensed, various IN vaccines against SARS-CoV-2 are under intensive investigation, with 12 candidates reaching clinical trials at different phases. In this review, we give a detailed description about current status of IN COVID-19 vaccines, including virus-vectored vaccines, recombinant subunit vaccines and live attenuated vaccines. The ongoing clinical trials for IN vaccines are highlighted. Additionally, the underlying mechanisms of mucosal immunity and potential mucosal adjuvants and nasal delivery devices are also summarized.

Process Development for Newcastle Disease Virus-Vectored Vaccines in Serum-Free Vero Cell Suspension Cultures

The ongoing COVID-19 pandemic drew global attention to infectious diseases, attracting numerous resources for development of pandemic preparedness plans and vaccine platforms—technologies with robust manufacturing processes that can quickly be pivoted to target emerging diseases. Newcastle Disease Virus (NDV) has been studied as a viral vector for human and veterinary vaccines, but its production relies heavily on embryonated chicken eggs, with very few studies producing NDV in cell culture. Here, NDV is produced in suspension Vero cells, and analytical assays (TCID₅₀ and ddPCR) are developed to quantify infectious and total viral titer. NDV-GFP and NDV-FLS (SARS-CoV-2 full-length spike protein) constructs were adapted to replicate in Vero and HEK293 suspension cultures using serum-free media, while fine-tuning parameters such as MOI, temperature, and trypsin concentration. Shake flask productions with Vero cells resulted in infectious titers of 1.07 × 10⁸ TCID₅₀/mL for NDV-GFP and 1.33 × 10⁸ TCID₅₀/mL for NDV-FLS. Production in 1 L batch bioreactors also resulted in high titers in culture supernatants, reaching 2.37 × 10⁸ TCID₅₀/mL for NDV-GFP and 3.16 × 10⁷ TCID₅₀/mL for NDV-FLS. This shows effective NDV production in cell culture, building the basis for a scalable vectored-vaccine manufacturing process that can be applied to different targets.