Nanovaccines against Viral Infectious Diseases

Revolutionizing Nanovaccines: A New Era of Immunization

Infectious diseases continue to pose a significant global health threat. To combat these challenges, innovative vaccine technologies are urgently needed. Nanoparticles (NPs) have unique properties and have emerged as a promising platform for developing next-generation vaccines. Nanoparticles are revolutionizing the field of vaccine development, offering a new era of immunization. They allow the creation of more effective, stable, and easily deliverable vaccines. Various types of NPs, including lipid, polymeric, metal, and virus-like particles, can be employed to encapsulate and deliver vaccine components, such as mRNA or protein antigens. These NPs protect antigens from degradation, target them to specific immune cells, and enhance antigen presentation, leading to robust and durable immune responses. Additionally, NPs can simultaneously deliver multiple vaccine components, including antigens, and adjuvants, in a single formulation, simplifying vaccine production and administration. Nanovaccines offer a promising approach to combat food- and water-borne bacterial diseases, surpassing traditional formulations. Further research is needed to address the global burden of these infections. This review highlights the potential of NPs to revolutionize vaccine platforms. We explore their mechanisms of action, current applications, and emerging trends. The review discusses the limitations of nanovaccines, innovative solutions and the potential role of artificial intelligence in developing more effective and accessible nanovaccines to combat infectious diseases.

Gold Nanoparticles as a Platform for Delivery of Immunogenic Peptides to THP-1 Derived Macrophages: Insights into Nanotoxicity

BACKGROUND

Peptide-based nanovaccines have emerged as a promising strategy for combating infectious diseases, as they overcome the low immunogenicity that is inherent to short epitope-containing synthetic peptides. Gold nanoparticles (AuNPs) present several advantages as peptide nanocarriers, but a deeper understanding of the design criteria is paramount to accelerate the development of peptide-AuNPs nanoconjugates (p-AuNPs).

METHODS

Herein, we synthesized and characterized p-AuNPs of 23 nm (p-Au23) and 68 nm (p-Au68) with varying levels of peptide surface coverage and different peptide designs, investigating their effect on the cell viability (cell death and mitochondrial activity), cellular uptake, and cathepsin B activity in THP-1 macrophages.

RESULTS

p-Au23 proved no negative effect in the cell viability and high levels of nanoconjugate uptake, but p-Au68 induced strong toxicity to the cell line. The peptide sequences were successfully designed with spacer regions and a cell-penetrating peptide (pTAT) that enhanced cellular uptake and cathepsin B activity for p-Au23, while pTAT induced severe effects in the THP-1 viability (~40-60% cell death).

CONCLUSIONS

These findings provide valuable insight into the design criteria of AuNPs and immunogenic peptides, along with nanotoxicity effects associated with AuNP size and surface charge in human monocyte-derived macrophages.

T4 Phage Displaying Dual Antigen Clusters Against H3N2 Influenza Virus Infection

BACKGROUND

The current H3N2 influenza subunit vaccine exhibits weak immunogenicity, which limits its effectiveness in preventing and controlling influenza virus infections.

METHODS

In this study, we aimed to develop a T4 phage-based nanovaccine designed to enhance the immunogenicity of two antigens by displaying the HA1 and M2e antigens of the H3N2 influenza virus on each phage nanoparticle. Specifically, we fused the Soc protein with the HA1 antigen and the Hoc protein with the M2e antigen, assembling them onto a T4 phage that lacks Soc and Hoc proteins (Soc-Hoc-T4), thereby constructing a nanovaccine that concurrently presents both HA1 and M2e antigens.

RESULTS

The analysis of the optical density of the target protein bands indicated that each particle could display approximately 179 HA1 and 68 M2e antigen molecules. Additionally, animal experiments demonstrated that this nanoparticle vaccine displaying dual antigen clusters induced a stronger specific immune response, higher antibody titers, a more balanced Th1/Th2 immune response, and enhanced CD4+ and CD8+ T cell effects compared to immunization with HA1 and M2e antigen molecules alone. Importantly, mice immunized with the T4 phage displaying dual antigen clusters achieved full protection (100% protection) against the H3N2 influenza virus, highlighting its robust protective efficacy.

CONCLUSIONS

In summary, our findings indicate that particles based on a T4 phage displaying antigen clusters exhibit ideal immunogenicity and protective effects, providing a promising strategy for the development of subunit vaccines against various viruses beyond influenza.

Advancements in nanoparticle-based vaccine development against Japanese encephalitis virus: a systematic review

Vaccination remains the sole effective strategy for combating Japanese encephalitis (JE). Both inactivated and live attenuated vaccines exhibit robust immunogenicity. However, the production of these conventional vaccine modalities necessitates extensive cultivation of the pathogen, incurring substantial costs and presenting significant biosafety risks. Moreover, the administration of live pathogens poses potential hazards for individuals or animals with compromised immune systems or other health vulnerabilities. Subsequently, ongoing research endeavors are focused on the development of next-generation JE vaccines utilizing nanoparticle (NP) platforms. This systematic review seeks to aggregate the research findings pertaining to NP-based vaccine development against JE. A thorough literature search was conducted across established English-language databases for research articles on JE NP vaccine development published between 2000 and 2023. A total of twenty-eight published studies were selected for detailed analysis in this review. Of these, 16 studies (57.14%) concentrated on virus-like particles (VLPs) employing various structural proteins. Other approaches, including sub-viral particles (SVPs), biopolymers, and both synthetic and inorganic NP platforms, were utilized to a lesser extent. The results of these investigations indicated that, despite variations in the usage of adjuvants, dosages, NP types, antigenic proteins, and animal models employed across different studies, the candidate NP vaccines developed were capable of eliciting enhanced humoral and cellular adaptive immune responses, providing effective protection (70-100%) for immunized mice against lethal challenges posed by virulent Japanese encephalitis virus (JEV). In conclusion, prospective next-generation JE vaccines for humans and animals may emerge from these candidate formulations following further evaluation in subsequent vaccine development phases.

Emerging Cationic Nanovaccines

Cationic vaccines of nanometric sizes can directly perform the delivery of antigen(s) and immunomodulator(s) to dendritic cells in the lymph nodes. The positively charged nanovaccines are taken up by antigen-presenting cells (APCs) of the lymphatic system often originating the cellular immunological defense required to fight intracellular microbial infections and the proliferation of cancers. Cationic molecules imparting the positive charges to nanovaccines exhibit a dose-dependent toxicity which needs to be systematically addressed. Against the coronavirus, mRNA cationic nanovaccines evolved rapidly. Nowadays cationic nanovaccines have been formulated against several infections with the advantage of cationic compounds granting protection of nucleic acids in vivo against biodegradation by nucleases. Up to the threshold concentration of cationic molecules for nanovaccine delivery, cationic nanovaccines perform well eliciting the desired Th 1 improved immune response in the absence of cytotoxicity. A second strategy in the literature involves dilution of cationic components in biocompatible polymeric matrixes. Polymeric nanoparticles incorporating cationic molecules at reduced concentrations for the cationic component often result in an absence of toxic effects. The progress in vaccinology against cancer involves in situ designs for cationic nanovaccines. The lysis of transformed cancer cells releases several tumoral antigens, which in the presence of cationic nanoadjuvants can be systemically presented for the prevention of metastatic cancer. In addition, these local cationic nanovaccines allow immunotherapeutic tumor treatment.

Development of a Ferritin-Based Nanoparticle Vaccine against Classical Swine Fever

The occurrence of classical swine fever (CSF) poses a significant threat to the global swine industry. Developing an effective and safe vaccine is crucial for preventing and controlling CSF. Here, we constructed self-assembled ferritin nanoparticles fused with the classical swine fever virus (CSFV) E2 protein and a derived B cell epitope (Fe-E2B) using a baculovirus expression system (BVES), demonstrating enhanced immunogenicity. Furthermore, we provide a detailed evaluation of the immunological efficacy of the FeE2B in rabbits. The results showed that robust and sustained antibody responses were detected in rabbits immunized with the Fe-E2B nanoparticle vaccine, comparable to those elicited by commercially available vaccines. Additionally, we demonstrated that the vaccine effectively activated crucial immune factors IFN-γ and IL-4 in vivo, increasing their levels by 1.41-fold and 1.39-fold, respectively. Immunization with Fe-E2B enabled rabbits to avoid viremia and stereotypic fever after CSFV challenge. In conclusion, this study highlights the potential of ferritin nanoparticles as antigen-presenting carriers to induce robust immune responses, proposing a candidate vaccine strategy for the prevention and control of CSF.

Functionally Designed Nanovaccines against SARS-CoV-2 and Its Variants

COVID-19, generated by SARS-CoV-2, has significantly affected healthcare systems worldwide. The epidemic has highlighted the urgent need for vaccine development. Besides the conventional vaccination models, which include live-attenuated, recombinant protein, and inactivated vaccines, nanovaccines present a distinct opportunity to progress vaccine research and offer convenient alternatives. This review highlights the many widely used nanoparticle vaccine vectors, outlines their benefits and drawbacks, and examines recent developments in nanoparticle vaccines to prevent SARS-CoV-2. It also offers a thorough overview of the many advantages of nanoparticle vaccines, including an enhanced host immune response, multivalent antigen delivery, and efficient drug delivery. The main objective is to provide a reference for the development of innovative antiviral vaccines.

Self-Assembling Nanoparticle Hemagglutinin Influenza Vaccines Induce High Antibody Response

As a highly pathogenic avian virus, H5 influenza poses a serious threat to livestock, the poultry industry, and public health security. Hemagglutinin (HA) is both the dominant epitope and the main target of influenza-neutralizing antibodies. Here, we designed a nanoparticle hemagglutinin influenza vaccine to improve the immunogenicity of the influenza vaccine. In this study, HA5 subtype influenza virus was used as the candidate antigen and was combined with the artificially designed double-branch scaffold protein I53_dn5 A and B. A structurally correct and bioactive trimer HA5-I53_dn5B/Y98F was obtained through secretion and purification using an insect baculovirus expression system; I53_dn5A was obtained by purification using a prokaryotic expression system. HA5-I53_dn5B/Y98F and I53_dn5A self-assembled into spherical nanoparticles (HA5-I53_dn5) in vitro with a diameter of about 45 nm. Immunization and serum test results showed that both HA5-I53_dn5B/Y98F and HA5-I53_dn5 could induce HA5-specific antibodies; however, the immunogenicity of HA5-I53_dn5 was better than that of HA5-I53_dn5B/Y98F. Groups treated with HA5-I53_dn5B and HA5-I53_dn5 nanoparticles produced IgG antibody titers that were not statistically different from those of the nanoparticle-containing adjuvant group. This production of trimerized HA5-I53_dn5B and HA5-I53_dn5 nanoparticles using baculovirus expression provides a reference for the development of novel, safe, and efficient influenza vaccines.

Harnessing Nanovaccines for Effective Immunization─A Special Concern on COVID-19: Facts, Fidelity, and Future Prospective

Nanotechnology has emerged as a transformative pathway in vaccine research and delivery. Nanovaccines, encompassing lipid and nonlipid formulations, exhibit considerable advantages over traditional vaccine techniques, including enhanced antigen stability, heightened immunogenicity, targeted distribution, and the potential for codelivery with adjuvants or immune modulators. This review provides a comprehensive overview of the latest advancements and applications of lipid and non-lipid-based nanovaccines in current vaccination strategies for immunization. The review commences by outlining the fundamental concepts underlying lipid and nonlipid nanovaccine design before delving into the diverse components and production processes employed in their development. Subsequently, a comparative analysis of various nanocarriers is presented, elucidating their distinct physicochemical characteristics and impact on the immune response, along with preclinical and clinical studies. The discussion also highlights how nanotechnology enables the possibility of personalized and combined vaccination techniques, facilitating the creation of tailored nanovaccines to meet the individual patient needs. The ethical aspects concerning the use of nanovaccines, as well as potential safety concerns and public perception, are also addressed. The study underscores the gaps and challenges that must be overcome before adopting nanovaccines in clinical practice. This comprehensive analysis offers vital new insights into lipid and nonlipid nanovaccine status. It emphasizes the significance of continuous research, collaboration among interdisciplinary experts, and regulatory measures to fully unlock the potential of nanotechnology in enhancing immunization and ensuring a healthier, more resilient society.

Nanovaccines: A game changing approach in the fight against infectious diseases

The field of nanotechnology has revolutionised global attempts to prevent, treat, and eradicate infectious diseases in the foreseen future. Nanovaccines have proven to be a valuable pawn in this novel technology. Nanovaccines are made up of nanoparticles that are associated with or prepared with components that can stimulate the host's immune system. In addition to their delivery capabilities, the nanocarriers have been demonstrated to possess intrinsic adjuvant properties, working as immune cell stimulators. Thus, nanovaccines have the potential to promote rapid as well as long-lasting humoral and cellular immunity. The nanovaccines have several possible benefits, including site-specific antigen delivery, increased antigen bioavailability, and a diminished adverse effect profile. To avail these benefits, several nanoparticle-based vaccines are being developed, including virus-like particles, liposomes, polymeric nanoparticles, nanogels, lipid nanoparticles, emulsion vaccines, exomes, and inorganic nanoparticles. Inspired by their distinctive properties, researchers are working on the development of nanovaccines for a variety of applications, such as cancer immunotherapy and infectious diseases. Although a few challenges still need to be overcome, such as modulation of the nanoparticle pharmacokinetics to avoid rapid elimination from the bloodstream by the reticuloendothelial system, The future prospects of this technology are also assuring, with multiple options such as personalised vaccines, needle-free formulations, and combination nanovaccines with several promising candidates.

An Overview of the Use of Nanoparticles in Vaccine Development

Vaccines represent one of the most significant advancements in public health since they prevented morbidity and mortality in millions of people every year. Conventionally, vaccine technology focused on either live attenuated or inactivated vaccines. However, the application of nanotechnology to vaccine development revolutionized the field. Nanoparticles emerged in both academia and the pharmaceutical industry as promising vectors to develop future vaccines. Regardless of the striking development of nanoparticles vaccines research and the variety of conceptually and structurally different formulations proposed, only a few of them advanced to clinical investigation and usage in the clinic so far. This review covered some of the most important developments of nanotechnology applied to vaccine technologies in the last few years, focusing on the successful race for the preparation of lipid nanoparticles employed in the successful anti-SARS-CoV-2 vaccines.

A Ferritin Nanoparticle-Based Zika Virus Vaccine Candidate Induces Robust Humoral and Cellular Immune Responses and Protects Mice from Lethal Virus Challenge

The severe consequences of the Zika virus (ZIKV) infections resulting in congenital Zika syndrome in infants and the autoimmune Guillain-Barre syndrome in adults warrant the development of safe and efficacious vaccines and therapeutics. Currently, there are no approved treatment options for ZIKV infection. Herein, we describe the development of a bacterial ferritin-based nanoparticle vaccine candidate for ZIKV. The viral envelope (E) protein domain III (DIII) was fused in-frame at the amino-terminus of ferritin. The resulting nanoparticle displaying the DIII was examined for its ability to induce immune responses and protect vaccinated animals upon lethal virus challenge. Our results show that immunization of mice with a single dose of the nanoparticle vaccine candidate (zDIII-F) resulted in the robust induction of neutralizing antibody responses that protected the animals from the lethal ZIKV challenge. The antibodies neutralized infectivity of other ZIKV lineages indicating that the zDIII-F can confer heterologous protection. The vaccine candidate also induced a significantly higher frequency of interferon (IFN)-γ positive CD4 T cells and CD8 T cells suggesting that both humoral and cell-mediated immune responses were induced by the vaccine candidate. Although our studies showed that a soluble DIII vaccine candidate could also induce humoral and cell-mediated immunity and protect from lethal ZIKV challenge, the immune responses and protection conferred by the nanoparticle vaccine candidate were superior. Further, passive transfer of neutralizing antibodies from the vaccinated animals to naïve animals protected against lethal ZIKV challenge. Since previous studies have shown that antibodies directed at the DIII region of the E protein do not to induce antibody-dependent enhancement (ADE) of ZIKV or other related flavivirus infections, our studies support the use of the zDIII-F nanoparticle vaccine candidate for safe and enhanced immunological responses against ZIKV.