Enhanced mucosal immune responses and reduced viral load in the respiratory tract of ferrets to intranasal lipid nanoparticle-based SARS-CoV-2 proteins and mRNA vaccines

Novel vaccine strategies to induce respiratory mucosal immunity: advances and implications

Rapid advances in vaccine technology are becoming increasingly important in tackling global health crises caused by respiratory virus infections. While traditional vaccines, primarily administered by intramuscular injection, have proven effective, they often fail to provide the broad upper respiratory tract mucosal immunity, which is urgently needed for first-line control of respiratory viral infections. Furthermore, traditional intramuscular vaccines may not adequately address the immune escape of emerging virus variants. In contrast, respiratory mucosal vaccines developed using the body's mucosal immune response mechanism can simultaneously establish both systemic and mucosal immunity. This dual action effectively allows the respiratory mucosal immune system to function as the first line of defense, preventing infections at the entry points. This review highlights the efficacy of respiratory mucosal vaccines, including innovative delivery methods such as nasal and oral formulations, in enhancing local and systemic immune barriers. Notably, respiratory mucosal vaccines offer potential advantages in protecting against emerging virus variants and maintaining long-term and multidimensional immune memory in the upper respiratory tract. In addition, a combination of intramuscular and respiratory mucosal delivery of vaccines largely improves their coverage and effectiveness, providing valuable insights for future vaccine development and public inoculation strategies.

Cell membrane fusion composite lipid nanocarrier: preparation and evaluation of anti-tumor effects

With the advancements in nanotechnology and biomaterials science, the development of nanodrug delivery systems (Nano-DDSs) has provided opportunities for the realization of precise targeted treatment of malignant tumors. Liposomes have become a type of DDS with early clinical application and mature development due to their excellent tissue-targeting capacity and outstanding biocompatibility. However, several obstacles remain, such as recognition and clearance by the immune system, a short half-life, and poor tumor targeting. To address these problems, we propose a new method to transform liposomes, using fusion to reassemble the extracted natural cell membranes and artificial phospholipids to form a composite nanolipid carrier (recombined lipid nanocarriers (RLNs)). We evaluated the different types of cell membrane composite lipid nanocarriers based on parameters such as particle size, stability, drug loading and release capabilities, in vitro and in vivo tumor-targeting efficacy, and safety. The results indicated that these novel tumor cell-derived membrane fusion lipid nanocarriers exhibited promising antitumor effects and safety profiles, offering insights for precision cancer treatment.

Pathogenesis and virulence of coronavirus disease: Comparative pathology of animal models for COVID-19

Animal models that can replicate clinical and pathologic features of severe human coronavirus infections have been instrumental in the development of novel vaccines and therapeutics. The goal of this review is to summarize our current understanding of the pathogenesis of coronavirus disease 2019 (COVID-19) and the pathologic features that can be observed in several currently available animal models. Knowledge gained from studying these animal models of SARS-CoV-2 infection can help inform appropriate model selection for disease modelling as well as for vaccine and therapeutic developments.

Advances and future perspectives of intranasal drug delivery: A scientometric review

Intranasal drug delivery is as a noninvasive and efficient approach extensively utilized for treating the local, central nervous system, and systemic diseases. Despite numerous reviews delving into the application of intranasal drug delivery across biomedical fields, a comprehensive analysis of advancements and future perspectives remains elusive. This review elucidates the research progress of intranasal drug delivery through a scientometric analysis. It scrutinizes several challenges to bolster research in this domain, encompassing a thorough exploration of entry and elimination mechanisms specific to intranasal delivery, the identification of drugs compatible with the nasal cavity, the selection of dosage forms to surmount limited drug-loading capacity and poor solubility, and the identification of diseases amenable to the intranasal delivery strategy. Overall, this review furnishes a perspective aimed at galvanizing future research and development concerning intranasal drug delivery.

Intranasal G5-BGG/pDNA Vaccine Elicits Protective Systemic and Mucosal Immunity against SARS-CoV-2 by Transfecting Mucosal Dendritic Cells

Infectious disease pandemics, including the coronavirus disease 2019 pandemic, have heightened the demand for vaccines. Although parenteral vaccines induce robust systemic immunity, their effectiveness in respiratory mucosae is limited. Considering the crucial role of nasal-associated lymphoid tissue (NALT) in mucosal immune responses, in this study, the intranasal complex composed of G5-BGG and antigen-expressing plasmid DNA (pSP), named G5-BGG/pSP complex, is developed to activate NALT and to promote both systemic and mucosal immune defense. G5-BGG/pSP could traverse mucosal barriers and deliver DNA to the target cells because of its superior nasal retention and permeability characteristics. The intranasal G5-BGG/pSP complex elicits robust antigen-specific immune responses, such as the notable production of IgG antibody against several virus variants. More importantly, it induces elevated levels of antigen-specific IgA antibody and a significant expansion of the lung-resident T lymphocyte population. Notably, the intranasal G5-BGG/pSP complex results in antigen expression and maturation of dendritic cells in nasal mucosae. These findings exhibit the potential of G5-BGG, a novel cationic material, as an effective gene carrier for intranasal vaccines to obtain robust systemic and mucosal immunity.

An intranasal live-attenuated SARS-CoV-2 vaccine limits virus transmission

The development of effective SARS-CoV-2 vaccines has been essential to control COVID-19, but significant challenges remain. One problem is intramuscular administration, which does not induce robust mucosal immune responses in the upper airways-the primary site of infection and virus shedding. Here we compare the efficacy of a mucosal, replication-competent yet fully attenuated virus vaccine, sCPD9-ΔFCS, and the monovalent mRNA vaccine BNT162b2 in preventing transmission of SARS-CoV-2 variants B.1 and Omicron BA.5 in two scenarios. Firstly, we assessed the protective efficacy of the vaccines by exposing vaccinated male Syrian hamsters to infected counterparts. Secondly, we evaluated transmission of the challenge virus from vaccinated and subsequently challenged male hamsters to naïve contacts. Our findings demonstrate that the live-attenuated vaccine (LAV) sCPD9-ΔFCS significantly outperformed the mRNA vaccine in preventing virus transmission in both scenarios. Our results provide evidence for the advantages of locally administered LAVs over intramuscularly administered mRNA vaccines in preventing infection and reducing virus transmission.

Can the Revolution in mRNA-Based Vaccine Technologies Solve the Intractable Health Issues of Current Ruminant Production Systems?

To achieve the World Health Organization's global Sustainable Development Goals, increased production of high-quality protein for human consumption is required while minimizing, ideally reducing, environmental impacts. One way to achieve these goals is to address losses within current livestock production systems. Infectious diseases are key limiters of edible protein production, affecting both quantity and quality. In addition, some of these diseases are zoonotic threats and potential contributors to the emergence of antimicrobial resistance. Vaccination has proven to be highly successful in controlling and even eliminating several livestock diseases of economic importance. However, many livestock diseases, both existing and emerging, have proven to be recalcitrant targets for conventional vaccination technologies. The threat posed by the COVID-19 pandemic resulted in unprecedented global investment in vaccine technologies to accelerate the development of safe and efficacious vaccines. While several vaccination platforms emerged as front runners to meet this challenge, the clear winner is mRNA-based vaccination. The challenge now is for livestock industries and relevant stakeholders to harness these rapid advances in vaccination to address key diseases affecting livestock production. This review examines the key features of mRNA vaccines, as this technology has the potential to control infectious diseases of importance to livestock production that have proven otherwise difficult to control using conventional approaches. This review focuses on the challenging diseases of ruminants due to their importance in global protein production. Overall, the current literature suggests that, while mRNA vaccines have the potential to address challenges in veterinary medicine, further developments are likely to be required for this promise to be realized for ruminant and other livestock species.

SARS-CoV-2 Aerosol and Intranasal Exposure Models in Ferrets

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of the worldwide COVID-19 pandemic. Animal models are extremely helpful for testing vaccines and therapeutics and for dissecting the viral and host factors that contribute to disease severity and transmissibility. Here, we report the assessment and comparison of intranasal and small particle (~3 µm) aerosol SARS-CoV-2 exposure in ferrets. The primary endpoints for analysis were clinical signs of disease, recovery of the virus in the upper respiratory tract, and the severity of damage within the respiratory tract. This work demonstrated that ferrets were productively infected with SARS-CoV-2 following either intranasal or small particle aerosol exposure. SARS-CoV-2 infection of ferrets resulted in an asymptomatic disease course following either intranasal or small particle aerosol exposure, with no clinical signs, significant weight loss, or fever. In both aerosol and intranasal ferret models, SARS-CoV-2 replication, viral genomes, and viral antigens were detected within the upper respiratory tract, with little to no viral material detected in the lungs. The ferrets exhibited a specific IgG immune response to the SARS-CoV-2 full spike protein. Mild pathological findings included inflammation, necrosis, and edema within nasal turbinates, which correlated to positive immunohistochemical staining for the SARS-CoV-2 virus. Environmental sampling was performed following intranasal exposure of ferrets, and SARS-CoV-2 genomic material was detected on the feeders and nesting areas from days 2-10 post-exposure. We conclude that both intranasal and small particle aerosol ferret models displayed measurable parameters that could be utilized for future studies, including transmission studies and testing SARS-CoV-2 vaccines and therapeutics.

Mucosal SARS-CoV-2 Nanoparticle Vaccine Based on Mucosal Adjuvants and Its Immune Effectiveness by Intranasal Administration

SARS-CoV-2 is a respiratory virus that causes significant threats to human health. Mucosal immunity provides a first-line defense to prevent the infection of SARS-CoV-2 in the respiratory tract. Because most SARS-CoV-2 vaccines could not stimulate mucosal immunity in the respiratory tract, appropriate mucosal adjuvants or delivery systems are needed for mucosal vaccine development. Mannan, polyarginine, and 2',3'-cGAMP are three mucosal adjuvants that could stimulate mucosal immunity. In the present study, the three adjuvants were assembled with a receptor-binding domain (RBD) by electrostatic interaction to generate a nanoparticle vaccine (RBD-MP-cG). RBD-MP-cG elicited mucosal IgA and IgG response in bronchoalveolar lavage and nasal lavage by intranasal administration. It induced a robust RBD-specific antibody response, high levels of protective neutralizing antibody, and ACE2-blocking activity in the mouse sera. It stimulated the splenic secretion of high levels of Th1-, Th2-, and Th17-type cytokines. Thus, RBD-MP-cG elicited strong mucosal immunity and systematic immunity by intranasal administration. RBD-MP-cG was expected to act as a safe, effective, and easily produced mucosal nanoparticle vaccine to combat the infection of SARS-CoV-2.

Advances in intranasal vaccine delivery: A promising non-invasive route of immunization

The importance of vaccination has been proven particularly significant the last three years, as it is revealed to be the most efficient weapon for the prevention of several infections including SARS-COV-2. Parenteral vaccination is the most applicable method of immunization, for the prevention of systematic and respiratory infections, or central nervous system disorders, involving T and B cells to a whole-body immune response. However, the mucosal vaccines, such as nasal vaccines, can additionally activate the immune cells localized on the mucosal tissue of the upper and lower respiratory tract. This dual stimulation of the immune system, along with their needle-free administration favors the development of novel nasal vaccines to produce long-lasting immunity. In recent years, the nanoparticulate systems have been extensively involved in the formulation of nasal vaccines as polymeric, polysaccharide and lipid ones, as well as in the form of proteosomes, lipopeptides and virosomes. Advanced delivery nanosystems have been designed and evaluated as carriers or adjuvants for nasal vaccination. To this end, several nanoparticulate vaccines are undergone clinical trials as promising candidates for nasal immunization, while nasal vaccines against influenza type A and B and hepatitis B have been approved by health authorities. This comprehensive literature review aims to summarize the critical aspects of these formulations and highlight their potential for the future establishment of nasal vaccination. Both preclinical (in vitro and in vivo) and clinical studies are incorporated, summarized, and critically discussed, as well as the limitations of nasal immunization.