An H1-H3 chimeric influenza virosome confers complete protection against lethal challenge with PR8 (H1N1) and X47 (H3N2) viruses in mice

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.

Safety and potency of BIV1-CovIran inactivated vaccine candidate for SARS-CoV-2: A preclinical study

The development of effective and safe COVID‐19 vaccines is a major move forward in our global effort to control the SARS‐CoV‐2 pandemic. The aims of this study were (1) to develop an inactivated whole‐virus SARS‐CoV‐2 candidate vaccine named BIV1‐CovIran and (2) to determine the safety and potency of BIV1‐CovIran inactivated vaccine candidate against SARS‐CoV‐2. Infectious virus was isolated from nasopharyngeal swab specimen and propagated in Vero cells with clear cytopathic effects in a biosafety level‐3 facility using the World Health Organization’s laboratory biosafety guidance related to COVID‐19. After characterisation of viral seed stocks, the virus working seed was scaled‐up in Vero cells. After chemical inactivation and purification, it was formulated with alum adjuvant. Finally, different animal species were used to determine the toxicity and immunogenicity of the vaccine candidate. The study showed the safety profile in studied animals including guinea pig, rabbit, mice and monkeys. Immunisation at two different doses (3 or 5 μg per dose) elicited a high level of SARS‐CoV‐2 specific and neutralising antibodies in mice, rabbits and nonhuman primates. Rhesus macaques were immunised with the two‐dose schedule of 5 or 3 μg of the BIV1‐CovIran vaccine and showed highly efficient protection against 10⁴ TCID50 of SARS‐CoV‐2 intratracheal challenge compared with the control group. These results highlight the BIV1‐CovIran vaccine as a potential candidate to induce a strong and potent immune response that may be a promising and feasible vaccine to protect against SARS‐CoV‐2 infection.

A recombinant herpes virus expressing influenza hemagglutinin confers protection and induces antibody-dependent cellular cytotoxicity

Despite widespread yearly vaccination, influenza leads to significant morbidity and mortality across the globe. To make a more broadly protective influenza vaccine, it may be necessary to elicit antibodies that can activate effector functions in immune cells, such as antibody-dependent cellular cytotoxicity (ADCC). There is growing evidence supporting the necessity for ADCC in protection against influenza and herpes simplex virus (HSV), among other infectious diseases. An HSV-2 strain lacking the essential glycoprotein D (gD), was used to create ΔgD-2, which is a highly protective vaccine against lethal HSV-1 and HSV-2 infection in mice. It also elicits high levels of IgG2c antibodies that bind FcγRIV, a receptor that activates ADCC. To make an ADCC-eliciting influenza vaccine, we cloned the hemagglutinin (HA) gene from an H1N1 influenza A strain into the ΔgD-2 HSV vector. Vaccination with ΔgD-2::HA_PR8 was protective against homologous influenza challenge and elicited an antibody response against HA that inhibits hemagglutination (HAI⁺), is predominantly IgG2c, strongly activates FcγRIV, and protects against influenza challenge following passive immunization of naïve mice. Prior exposure of mice to HSV-1, HSV-2, or a replication-defective HSV-2 vaccine (dl5-29) does not reduce protection against influenza by ΔgD-2::HA_PR8 This vaccine also continues to elicit protection against both HSV-1 and HSV-2, including high levels of IgG2c antibodies against HSV-2. Mice lacking the interferon-α/β receptor and mice lacking the interferon-γ receptor were also protected against influenza challenge by ΔgD-2::HA_PR8 Our results suggest that ΔgD-2 can be used as a vaccine vector against other pathogens, while also eliciting protective anti-HSV immunity.

Virosome-based nanovaccines; a promising bioinspiration and biomimetic approach for preventing viral diseases: A review

Vaccination is the most effective means of controlling infectious disease-related morbidity and mortality. However, due to low immunogenicity of viral antigens, nanomedicine as a new opportunity in new generation of vaccine advancement attracted researcher encouragement. Virosome is a lipidic nanomaterial emerging as FDA approved nanocarriers with promising bioinspiration and biomimetic potency against viral infections. Virosome surface modification with critical viral fusion proteins is the cornerstone of vaccine development. Surface antigens at virosomes innovatively interact with targeted receptors on host cells that evoke humoral or cellular immune responses through antibody-producing B cell and internalization by endocytosis-mediated pathways. To date, several nanovaccine based on virosome formulations have been commercialized against widespread and life-threatening infections. Recently, Great efforts were made to fabricate a virosome-based vaccine platform against a new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus. Thus, this review provides a novel overview of the virosome based nanovaccine production, properties, and application on the viral disease, especially its importance in SARS-CoV-2 vaccine discovery.

Bioinspired and Biomimetic Nanotherapies for the Treatment of Infectious Diseases

There are still great challenges for the effective treatment of infectious diseases, although considerable achievement has been made by using antiviral and antimicrobial agents varying from small-molecule drugs, peptides/proteins, to nucleic acids. The nanomedicine approach is emerging as a new strategy capable of overcoming disadvantages of molecular therapeutics and amplifying their anti-infective activities, by localized delivery to infection sites, reducing off-target effects, and/or attenuating resistance development. Nanotechnology, in combination with bioinspired and biomimetic approaches, affords additional functions to nanoparticles derived from synthetic materials. Herein, we aim to provide a state-of-the-art review on recent progress in biomimetic and bioengineered nanotherapies for the treatment of infectious disease. Different biomimetic nanoparticles, derived from viruses, bacteria, and mammalian cells, are first described, with respect to their construction and biophysicochemical properties. Then, the applications of diverse biomimetic nanoparticles in anti-infective therapy are introduced, either by their intrinsic activity or by loading and site-specifically delivering various molecular drugs. Bioinspired and biomimetic nanovaccines for prevention and/or therapy of infectious diseases are also highlighted. At the end, major translation issues and future directions of this field are discussed.

Oil-in-water emulsion formulated with eucalyptus leaves extract inhibit influenza virus binding and replication in vitro

Throughout human history, the human-beings have been used different types of plants as antimicrobial agents in fight against infectious diseases. Influenza virus is one of the most common causes of respiratory infection and transmitted through direct contact with flu infected individuals and contaminated substances or droplets. In the current study, both oil-in-water and water-in-oil emulsions with hydroalcoholic extract of eucalyptus leaves (OLHE) were developed and their antiviral efficiency was evaluated. To doing so, Madin-Darbey Canine Kidney (MDCK) cells were treated with effective minimal cytotoxic concentration of the formulated emulsions. The treated cells were then infected with 50% cell culture infectious dose (100 CCID50) of the A/H1N1 virus (the swine flu). The viral titers were measured by hemagglutination (HA) and cell culture infectious dose 50% (CCID50) assays. Also, to check the virus binding inhibition via the formulated extract, the viruses were incubated with the formulated extracts. Our study showed that the oil-in-water emulsions formulated with 2% eucalyptus leaves extract inhibited virus replication completely when the cells were infected by 100 CCID50 and decreased HA titer up to four fold. Therefore, this formulation, may hold promising application to prevent influenza virus transmission through direct contact among children and passengers.

Nanoparticles: augmenting tumor antigen presentation for vaccine and immunotherapy treatments of cancer

The major goal of immunity is maintaining host survival. Toward this, immune cells recognize and eliminate targets that pose a danger. Primarily, these are external invaders (pathogens) and internal invaders (cancers). Their recognition relies on distinguishing foreign components (antigens) from self-antigens. Since cancer cells are the host's own cells that are harmfully altered, they are difficult to distinguish from normal self. Furthermore, the antigens least resembling the host are often sequestered in parts of the tumor least accessible to immune responses. Therefore, to sufficiently boost immunity, these tumor antigens must be exposed to the immune system. Toward this, nanoparticles provide an innovating means of tumor antigen presentation and are destined to become an integral part of cancer immunotherapy.

Autophagy induction regulates influenza virus replication in a time-dependent manner

PURPOSE

Autophagy plays a key role in host defence responses against microbial infections by promoting degradation of pathogens and participating in acquired immunity. The interaction between autophagy and viruses is complex, and this pathway is hijacked by several viruses. Influenza virus (IV) interferes with autophagy through its replication and increases the accumulation of autophagosomes by blocking lysosome fusion. Thus, autophagy could be an effective area for antiviral research.

METHODOLOGY

In this study, we evaluated the effect of autophagy on IV replication. Two cell lines were transfected with Beclin-1 expression plasmid before (prophylactic approach) and after (therapeutic approach) IV inoculation.Results/Key findings. Beclin-1 overexpression in the cells infected by virus induced autophagy to 26 %. The log10haemagglutinin titre and TCID50 (tissue culture infective dose giving 50 % infection) of replicating virus were measured at 24 and 48 h post-infection. In the prophylactic approach, the virus titre was enhanced significantly at 24 h post-infection (P≤0.01), but it was not significantly different from the control at 48 h post-infection. In contrast, the therapeutic approach of autophagy induction inhibited the virus replication at 24 and 48 h post-infection. Additionally, we showed that inhibition of autophagy using 3-methyladenine reduced viral replication.

CONCLUSION

This study revealed that the virus (H1N1) titre was controlled in a time-dependent manner following autophagy induction in host cells. Manipulation of autophagy during the IV life cycle can be targeted both for antiviral aims and for increasing viral yield for virus production.

Suppressive Effects of Chronic Stress on Influenza Virus Protection after Vaccination with Plasmid DNA-Encoded Nucleoprotein

BACKGROUND

Influenza is a highly infectious and acute respiratory disease caused by an infection of the host respiratory tract mucosa by the influenza virus. The use of DNA vaccines that express conserved genes such as nucleoprotein (NP) represents a new method of vaccination against influenza. In this study, the effect of chronic stress on the efficiency of this type of vaccine has been evaluated in a mouse model.

METHODS

The NP DNA vaccine was administered intradermally 3 times on days 0, 3 and 6 to stressed and nonstressed male BALB/c mice. Two weeks after the last immunization, half of these mice were challenged with A/Puerto Rico/8/34 (PR8) influenza virus and were weighed for 12 days, and their mortality rate was assessed during this period. The cellular immune response of the other half of the mice was evaluated by cytotoxicity assay.

RESULTS

The results indicate a significant reduction in the cytotoxic T-lymphocyte response of stressed mice in comparison with unstressed mice. Also, the percentage of weight loss and mortality after the challenge in stressed mice was significantly increased compared to the other group.

CONCLUSION

These results indicate that the NP DNA vaccine is not able to induce any effective cytotoxic T-lymphocyte response against influenza virus in stressed mice and cannot induce protective immunity against influenza infection in this group of mice.