Nanoparticles target distinct dendritic cell populations according to their size

A Thermal-Stable Protein Nanoparticle That Stimulates Long Lasting Humoral Immune Response

A thermally stable vaccine platform is considered the missing piece of vaccine technology. In this article, we reported the creation of a novel protein nanoparticle and assessed its ability to withstand extended high temperature incubation while stimulating a long-lasting humoral immune response. This protein nanoparticle was assembled from a fusion protein composed of an amphipathic helical peptide derived from the M2 protein of the H5N1 influenza virus (AH3) and a superfolder green fluorescent protein (sfGFP). Its proposed structure was modeled according to transmission electronic microscope (TEM) images of protein nanoparticles. From this proposed protein model, we created a mutant with two gain-of-function mutations that work synergistically on particle stability. A protein nanoparticle assembled from this gain-of-function mutant is able to remove a hydrophobic patch from its surface. This gain-of-function mutant also contributes to the higher thermostability of protein nanoparticles and stimulates a long lasting humoral immune response after a single immunization. This assembled nanoparticle showed increasing particle stability at higher temperatures and salt concentrations. This novel protein nanoparticle may serve as a thermally-stable platform for vaccine development.

Protein Nanoparticle-Mediated Delivery of Recombinant Influenza Hemagglutinin Enhances Immunogenicity and Breadth of the Antibody Response

The vast majority of seasonal influenza vaccines administered each year are derived from virus propagated in eggs using technology that has changed little since the 1930s. The immunogenicity, durability, and breadth of response would likely benefit from a recombinant nanoparticle-based approach. Although the E2 protein nanoparticle (NP) platform has been previously shown to promote effective cell-mediated responses to peptide epitopes, it has not yet been reported to deliver whole protein antigens. In this study, we synthesized a novel maleimido tris-nitrilotriacetic acid (NTA) linker to couple protein hemagglutinin (HA) from H1N1 influenza virus to the E2 NP, and we evaluated the HA-specific antibody responses using protein microarrays. We found that recombinant H1 protein alone is immunogenic in mice but requires two boosts for IgG to be detected and is strongly IgG1 (Th2) polarized. When conjugated to E2 NPs, IgG2c is produced leading to a more balanced Th1/Th2 response. Inclusion of the Toll-like receptor 4 agonist monophosphoryl lipid A (MPLA) significantly enhances the immunogenicity of H1-E2 NPs while retaining the Th1/Th2 balance. Interestingly, broader homo- and heterosubtypic cross-reactivity is also observed for conjugated H1-E2 with MPLA, compared to unconjugated H1 with or without MPLA. These results highlight the potential of an NP-based delivery of HA for tuning the immunogenicity, breadth, and Th1/Th2 balance generated by recombinant HA-based vaccination. Furthermore, the modularity of this protein-protein conjugation strategy may have utility for future vaccine development against other human pathogens.

Platforms, advances, and technical challenges in virus-like particles-based vaccines

Viral infectious diseases threaten human health and global stability. Several vaccine platforms, such as DNA, mRNA, recombinant viral vectors, and virus-like particle-based vaccines have been developed to counter these viral infectious diseases. Virus-like particles (VLP) are considered real, present, licensed and successful vaccines against prevalent and emergent diseases due to their non-infectious nature, structural similarity with viruses, and high immunogenicity. However, only a few VLP-based vaccines have been commercialized, and the others are either in the clinical or preclinical phases. Notably, despite success in the preclinical phase, many vaccines are still struggling with small-scale fundamental research owing to technical difficulties. Successful production of VLP-based vaccines on a commercial scale requires a suitable platform and culture mode for large-scale production, optimization of transduction-related parameters, upstream and downstream processing, and monitoring of product quality at each step. In this review article, we focus on the advantages and disadvantages of various VLP-producing platforms, recent advances and technical challenges in VLP production, and the current status of VLP-based vaccine candidates at commercial, preclinical, and clinical levels.

pH-Sensitive and Biodegradable Mn3(PO4)2·3H2O Nanoparticles as an Adjuvant of Protein-Based Bivalent COVID-19 Vaccine to Induce Potent and Broad-Spectrum Immunity

Developing a novel and potent adjuvant with great biocompatibility for immune response augmentation is of great significance to enhance vaccine efficacy. In this work, we prepared a long-term stable, pH-sensitive, and biodegradable Mn3(PO4)2·3H2O nanoparticle (nano-MnP) by simply mixing MnCl2/NaH2PO4/Na2HPO4 solution for the first time and employed it as an immune stimulant in the bivalent COVID-19 protein vaccine comprised of wild-type S1 (S1-WT) and Omicron S1 (S1-Omicron) proteins as antigens to elicit a broad-spectrum immunity. The biological experiments indicated that the nano-MnP could effectively activate antigen-presenting cells through the cGAS-STING pathway. Compared with the conventional Alum-adjuvanted group, the nano-MnP-adjuvanted bivalent vaccine elicited approximately 7- and 8-fold increases in IgG antibody titers and antigen-specific IFN-γ secreting T cells, respectively. Importantly, antisera of the nano-MnP-adjuvanted group could effectively cross-neutralize the SARS-CoV-2 and its five variants of concern (VOCs) including Alpha, Beta, Gamma, Delta, and Omicron, demonstrating that this bivalent vaccine based on S1-WT and S1-Omicron proteins is an effective vaccine design strategy to induce broad-spectrum immune responses. Collectively, this nano-MnP material may provide a novel and efficient adjuvant platform for various prophylactic and therapeutic vaccines and provide insights for the development of the next-generation manganese adjuvant.

Polymeric nanoparticle-based nanovaccines for cancer immunotherapy

Therapeutic cancer vaccines, which are designed to amplify tumor-specific T cell responses, have been envisioned as one of the most powerful tools for effective cancer immunotherapy. However, increasing the potency, quality and durability of the vaccine response remains a big challenge. In recent years, materials-based delivery systems focusing on the co-delivery of antigens and adjuvants to enhance cancer vaccination therapy have attracted increasing interest. Among various materials, polymeric nanoparticles (NPs) with different physicochemical properties which can incorporate multiple immunological cues are of great interest. In this review, the recent progress in the design and construction of both ex vivo subunit and in situ cancer vaccines using polymeric NPs is summarized. Especially, we will focus on how these NPs improve the adjuvanticity of vaccines. The design principles of polymeric NPs for ex vivo subunit cancer vaccines and in situ cancer vaccination are also discussed. Finally, we want to briefly discuss molecular chaperones in cancer immunity and the applications of our unique self-assembly mixed shell polymeric micelle-based nanochaperones for cancer vaccines.

Holistic View on the Structure of Immune Response: Petri Net Model

The simulation of immune response is a challenging task because quantitative data are scarce. Quantitative theoretical models either focus on specific cell-cell interactions or have to make assumptions about parameters. The broad variation of, e.g., the dimensions and abundance between lymph nodes as well as between individual patients hampers conclusive quantitative modeling. No theoretical model has been established representing a consensus on the set of major cellular processes involved in the immune response. In this paper, we apply the Petri net formalism to construct a semi-quantitative mathematical model of the lymph nodes. The model covers the major cellular processes of immune response and fulfills the formal requirements of Petri net models. The intention is to develop a model taking into account the viewpoints of experienced pathologists and computer scientists in the field of systems biology. In order to verify formal requirements, we discuss invariant properties and apply the asynchronous firing rule of a place/transition net. Twenty-five transition invariants cover the model, and each is assigned to a functional mode of the immune response. In simulations, the Petri net model describes the dynamic modes of the immune response, its adaption to antigens, and its loss of memory.

Lipid nanoparticles technology in vaccines: Shaping the future of prophylactic medicine

Throughout decades, the intrinsic power of the immune system to fight pathogens has inspired researchers to develop techniques that enable the prevention or treatment of infections via boosting the immune response against the target pathogens, which has led to the evolution of vaccines. The recruitment of Lipid nanoparticles (LNPs) as either vaccine delivery platforms or immunogenic modalities has witnessed a breakthrough recently, which has been crowned with the development of effective LNPs-based vaccines against COVID-19. In the current article, we discuss some principles of such a technology, with a special focus on the technical aspects from a translational perspective. Representative examples of LNPs-based vaccines against cancer, COVID-19, as well as other infectious diseases, autoimmune diseases, and allergies are highlighted, considering the challenges and promises. Lastly, the key features that can improve the clinical translation of this area of endeavor are inspired.

Exosome-based delivery of VP1 protein conferred enhanced resistance of mice to CVB3-induced viral myocarditis

Coxsackievirus B3 (CVB3) is an important cause of viral myocarditis with no vaccine available in clinic. Herein we constructed an exosome-based anti-CVB3 vaccine (Exo-VP1), and compared its immunogenicity and immunoprotection with our previously reported recombinant VP1 protein (rVP1) vaccine. We found that compared with the 25 μg rVP1 vaccine, Exo-VP1 vaccine containing only 2 μg VP1 protein induced much stronger CVB3-specific T cell proliferation and CTL responses (with an increase of more than 70% and 40% respectively), and elicited greater splenic Th1/CTL associated cytokines (IFN-γ, TNF-α and IL-12). Furthermore, higher IgG levels with increased neutralizing titers and avidity were also evidenced in Exo-VP1 group. Consistently, Exo-VP1 group exhibited enhanced resistance to viral myocarditis than rVP1 vaccine, reflected by reduced cardiac viral loads, improved myocardial inflammation and an increased survival rate. Collectively, we reported that Exo-VP1 might present a more potent CVB3 vaccine candidate than rVP1 vaccine.

Particle-Based therapies for antigen specific treatment of type 1 diabetes

Type 1 diabetes mellitus (T1D) is the leading metabolic disorder in children worldwide. Over time, incidence rates have continued to rise with 20 million individuals affected globally by the autoimmune disease. The current standard of care is costly and time-consuming requiring daily injections of exogenous insulin. T1D is mediated by autoimmune effector responses targeting autoantigens expressed on pancreatic islet β-cells. One approach to treat T1D is to skew the immune system away from an effector response by taking an antigen-specific approach to heighten a regulatory response through a therapeutic vaccine. An antigen-specific approach has been shown with soluble agents, but the effects have been limited. Micro or nanoparticles have been used to deliver a variety of therapeutic agents including peptides and immunomodulatory therapies to immune cells. Particle-based systems can be used to deliver cargo into the cell and microparticles can passively target phagocytic cells. Further, surface modification and controlled release of encapsulated cargo can enhance delivery over soluble agents. The induction of antigen-specific immune tolerance is imperative for the treatment of autoimmune diseases such as T1D. This review highlights studies that utilize particle-based platforms for the treatment of T1D.

Mycobacterium avium subsp. paratuberculosis antigens induce cellular immune responses in cattle without causing reactivity to tuberculin in the tuberculosis skin test

Mycobacterium avium subspecies paratuberculosis (MAP) causes chronic progressive granulomatous enteritis leading to diarrhea, weight-loss, and eventual death in ruminants. Commercially available vaccine provides only partial protection against MAP infection and can interfere with the use of current diagnostic tests for bovine tuberculosis in cattle. Here, we characterized immune responses in calves to vaccines containing four truncated MAP antigens as a fusion (Ag85A^202-347-SOD^1-72-Ag85B^173-330-74F^{1-148+669-786}), either displayed on protein particles, or expressed as a soluble recombinant MAP (rMAP) fusion protein as well as to commercially available Silirum^® vaccine. The rMAP fusion protein elicited the strongest antigen-specific antibody responses to both PPDA and recombinant antigen and strong and long-lasting T-cell immune responses to these antigens, as indicated by increased production of IFN-γ and IL-17A in antigen-stimulated whole blood cultures. The MAP fusion protein particle vaccine induced minimal antibody responses and weak IFN-γ responses but stimulated IL-17A responses to recombinant antigen. The immune response profile of Silirum^® vaccine was characterized by weak antibodies and strong IFN-γ and IL-17A responses to PPDA. Transcription analysis on antigen-stimulated leukocytes from cattle vaccinated with rMAP fusion protein showed differential expression of several immune response genes and genes involved in costimulatory signaling, TLR4, TLR2, PTX3, PTGS2, PD-L1, IL1B, IL2, IL6, IL12B, IL17A, IL22, IFNG, CD40, and CD86. Moreover, the expression of several genes of immune pathways correlated with cellular immune responses in the rMAP fusion protein vaccinated group. These genes have key roles in pathways of mycobacterial immunity, including autophagy, manipulation of macrophage-mediated killing, Th17- and regulatory T cells- (Treg) mediated responses. Calves vaccinated with either the rMAP fusion protein or MAP fusion protein particle vaccine did not induce reactivity to PPDA and PPDB in a comparative cervical skin test, whereas Silirum^® induced reactivity to these tuberculins in most of the vaccinated animals. Overall, our results suggest that a combination of recombinant MAP antigens in the form of a soluble fusion protein vaccine are capable of inducing strong antigen-specific humoral and a balanced Th1/Th17-cell immune response. These findings, together with the absence of reactivity to tuberculin, suggest this subunit vaccine could provide protective immunity against intracellular MAP infection in cattle without compromising the use of current bovine tuberculosis surveillance test.

Bioresponsive Immunotherapeutic Materials

The human immune system is an interaction network of biological processes, and its dysfunction is closely associated with a wide array of diseases, such as cancer, infectious diseases, tissue damage, and autoimmune diseases. Manipulation of the immune response network in a desired and controlled fashion has been regarded as a promising strategy for maximizing immunotherapeutic efficacy and minimizing side effects. Integration of "smart" bioresponsive materials with immunoactive agents including small molecules, biomacromolecules, and cells can achieve on-demand release of agents at targeted sites to reduce overdose-related toxicity and alleviate off-target effects. This review highlights the design principles of bioresponsive immunotherapeutic materials and discusses the critical roles of controlled release of immunoactive agents from bioresponsive materials in recruiting, housing, and manipulating immune cells for evoking desired immune responses. Challenges and future directions from the perspective of clinical translation are also discussed.

Metal-organic coordination polymers for delivery of immunomodulatory agents, and infectious disease and cancer vaccines

Metal-organic coordination polymers (CPs) are a broad class of materials that include metal-organic frameworks (MOFs). CPs are highly ordered crystalline materials that are composed of metal ions (or metal ion clusters) and multidentate organic ligands that serve as linkers. One-, two-, and three-dimensional CPs can be formed, with 2D and 3D structures referred to as MOFs. CPs have gained a lot of attention due to attractive structural features like structure versatility and tunability, and well-defined pores that enable the encapsulation of cargo. Further, CPs show a lot of promise for drug delivery applications, but only a very limited number of CPs are currently being evaluated in clinical trials. In this review, we outlined features that are desired for CP-based drug delivery platform, and briefly described most relevant characterization techniques. We highlighted some of the recent efforts directed toward developing CP-based drug delivery platforms with the emphasis on vaccines against cancer, infectious diseases, and viruses. We hope this review will be a helpful guide for those interested in the design and evaluation of CP-based immunological drug delivery platforms. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious Disease Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Protein-based nanocages for vaccine development

Protein nanocages have attracted considerable attention in various fields of nanomedicine due to their intrinsic properties, including biocompatibility, biodegradability, high structural stability, and ease of modification of their surfaces and inner cavities. In vaccine development, these protein nanocages are suited for efficient targeting to and retention in the lymph nodes and can enhance immunogenicity through various mechanisms, including excellent uptake by antigen-presenting cells and crosslinking with multiple B cell receptors. This review highlights the superiority of protein nanocages as antigen delivery carriers based on their physiological and immunological properties such as biodistribution, immunogenicity, stability, and multifunctionality. With a focus on design, we discuss the utilization and efficacy of protein nanocages such as virus-like particles, caged proteins, and artificial caged proteins against cancer and infectious diseases such as coronavirus disease 2019 (COVID-19). In addition, we summarize available knowledge on the protein nanocages that are currently used in clinical trials and provide a general outlook on conventional distribution techniques and hurdles faced, particularly for therapeutic cancer vaccines.

Self-assembled nanoparticles: A new platform for revolutionizing therapeutic cancer vaccines

Cancer vaccines have had some success in the past decade. Based on in-depth analysis of tumor antigen genomics, many therapeutic vaccines have already entered clinical trials for multiple cancers, including melanoma, lung cancer, and head and neck squamous cell carcinoma, which have demonstrated impressive tumor immunogenicity and antitumor activity. Recently, vaccines based on self-assembled nanoparticles are being actively developed as cancer treatment, and their feasibility has been confirmed in both mice and humans. In this review, we summarize recent therapeutic cancer vaccines based on self-assembled nanoparticles. We describe the basic ingredients for self-assembled nanoparticles, and how they enhance vaccine immunogenicity. We also discuss the novel design method for self-assembled nanoparticles that pose as a promising delivery platform for cancer vaccines, and the potential in combination with multiple therapeutic approaches.

Lipid Microparticles Show Similar Efficacy With Lipid Nanoparticles in Delivering mRNA and Preventing Cancer

PURPOSE

Messenger RNA (mRNA) has shown great promise for vaccine against both infectious diseases and cancer. However, mRNA is unstable and requires a delivery vehicle for efficient cellular uptake and degradation protection. So far, lipid nanoparticles (LNPs) represent the most advanced delivery platform for mRNA delivery. However, no published studies have compared lipid microparticles (LMPs) with lipid nanoparticles (LNPs) in delivering mRNA systematically, therefore, we compared the impact of particle size on delivery efficacy of mRNA vaccine and subsequent immune responses.

METHODS

Herein, we prepared 3 different size lipid particles, from nano-sized to micro-sized, and they loaded similar amounts of mRNA. These lipid particles were investigated both in vitro and in vivo, followed by evaluating the impact of particle size on inducing cellular and humoral immune responses.

RESULTS

In this study, all mRNA vaccines showed a robust immune response and lipid microparticles (LMPs) show similar efficacy with lipid nanoparticles (LNPs) in delivering mRNA and preventing cancer. In addition, immune adjuvants, either toll like receptors or active molecules from traditional Chinese medicine, can improve the efficacy of mRNA vaccines.

CONCLUSIONS

Considering the efficiency of delivery and endocytosis, besides lipid nanoparticles with size smaller than 150 nm, lipid microparticles (LMPs) also have the potential to be an alternative and promising delivery system for mRNA vaccines.

Nanoimmunoengineering strategies in cancer diagnosis and therapy

Cancer immunotherapy strategies in combination with engineered nanosystems have yielded beneficial results in the treatment of cancer and their application is increasing day by day. The pivotal role of stimuli-responsive nanosystems and nanomedicine-based cancer immunotherapy, as a subsidiary discipline in the field of immunology, cannot be ignored. Today, rapid advances in nanomedicine are used as a platform for exploring new therapeutic applications and modern smart healthcare management strategies. The progress of nanomedicine in cancer treatment has confirmed the findings of immunotherapy in the medical research phase. This study concentrates on approaches connected to the efficacy of nanoimmunoengineering strategies for cancer immunotherapies and their applications. By assessing improved approaches, different aspects of the nanoimmunoengineering strategies for cancer therapies are discussed in this study.

Virus-like Particles as Antiviral Vaccine: Mechanism, Design, and Application

Virus-like particles (VLPs) are viral structural protein that are noninfectious as they do not contain viral genetic materials. They are safe and effective immune stimulators and play important roles in vaccine development because of their intrinsic immunogenicity to induce cellular and humoral immune responses. In the design of antiviral vaccine, VLPs based vaccines are appealing multifunctional candidates with the advantages such as self-assembling nanoscaled structures, repetitive surface epitopes, ease of genetic and chemical modifications, versatility as antigen presenting platforms, intrinsic immunogenicity, higher safety profile in comparison with live-attenuated vaccines and inactivated vaccines. In this review, we discuss the mechanism of VLPs vaccine inducing cellular and humoral immune responses. We outline the impact of size, shape, surface charge, antigen presentation, genetic and chemical modification, and expression systems when constructing effective VLPs based vaccines. Recent applications of antiviral VLPs vaccines and their clinical trials are summarized.

Virus-like Particles for TEM Regulation and Antitumor Therapy

Tumor development and metastasis are intimately associated with the tumor microenvironment (TME), and it is difficult for vector-restricted drugs to act on the TME for long-term cancer immunotherapy. Virus-like particles (VLPs) are nanocage structures self-assembled from nucleic acid free viral proteins. Most VLPs range from 20-200 nm in diameter and can naturally drain into lymph nodes to induce robust humoral immunity. As natural nucleic acid nanocarriers, their surfaces can also be genetically or chemically modified to achieve functions such as TME targeting. This review focuses on the design ideas of VLP as nanocarriers and the progress of their research in regulating TME.

Mannosylated Polycations Target CD206+ Antigen-Presenting Cells and Mediate T-Cell-Specific Activation in Cancer Vaccination

Immunotherapy is deemed one of the most powerful therapeutic approaches to treat cancer. However, limited response and tumor specificity are still major challenges to address. Herein, mannosylated polycations targeting mannose receptor- are developed as vectors for plasmid DNA (pDNA)-based vaccines to improve selective delivery of genetic material to antigen-presenting cells and enhance immune cell activation. Three diblock glycopolycations (M₁₅A₁₂, M₂₉A₂₅, and M₅₈A₄₅) and two triblock copolymers (M₂₉A₂₉B₉ and M₆₂A₅₂B₃₂) are generated by using mannose (M), agmatine (A), and butyl (B) derivatives to target CD206, complex nucleic acids, and favor the endosomal escape, respectively. All glycopolycations efficiently complex pDNA at N/P ratios <5, protecting the pDNA from degradation in a physiological milieu. M₅₈A₄₅ and M₆₂A₅₂B₃₂ complexed with plasmid encoding for antigenic ovalbumin (pOVA) trigger the immune activation of cultured dendritic cells, which present the SIINFEKL antigenic peptide via specific major histocompatibility complex-I. Importantly, administration of M₅₈A₄₅/pOVA elicits SIINFEKL-specific T-cell response in C56BL/6 mice bearing the melanoma tumor model B16-OVA, well in line with a reduction in tumor growth. These results qualify mannosylation as an efficient strategy to target immune cells in cancer vaccination and emphasize the potential of these glycopolycations as effective delivery vehicles for nucleic acids.

Modular capsid decoration boosts adenovirus vaccine-induced humoral immunity against SARS-CoV-2

Adenovirus vector vaccines have been widely and successfully deployed in response to coronavirus disease 2019 (COVID-19). However, despite inducing potent T cell immunity, improvement of vaccine-specific antibody responses upon homologous boosting is modest compared with other technologies. Here, we describe a system enabling modular decoration of adenovirus capsid surfaces with antigens and demonstrate potent induction of humoral immunity against these displayed antigens. Ligand attachment via a covalent bond was achieved using a protein superglue, DogTag/DogCatcher (similar to SpyTag/SpyCatcher), in a rapid and spontaneous reaction requiring only co-incubation of ligand and vector components. DogTag was inserted into surface-exposed loops in the adenovirus hexon protein to allow attachment of DogCatcher-fused ligands on virus particles. Efficient coverage of the capsid surface was achieved using various ligands, with vector infectivity retained in each case. Capsid decoration shielded particles from vector neutralizing antibodies. In prime-boost regimens, adenovirus vectors decorated with the receptor-binding domain of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) spike induced >10-fold higher SARS-CoV-2 neutralization titers compared with an undecorated vector encoding spike. Importantly, decorated vectors achieved equivalent or superior T cell immunogenicity against encoded antigens compared with undecorated vectors. We propose capsid decoration using protein superglues as a novel strategy to improve efficacy and boostability of adenovirus-based vaccines and therapeutics.

Osmotic Pressure as Driving Force for Reducing the Size of Nanoparticles in Emulsions

We describe here a method to decrease particle size of nanoparticles synthesized by miniemulsion polymerization. Small nanoparticles or nanocapsules were obtained by generating an osmotic pressure to induce the diffusion of monomer molecules from the dispersed phase of a miniemulsion before polymerization to an upper oil layer. The size reduction is dependent on the difference in concentration of monomer in the dispersed phase and in the upper oil layer and on the solubility of the monomer in water. By labeling the emulsion droplets with a copolymer of stearyl methacrylate and a polymerizable dye, we demonstrated that the migration of the monomer to the upper hexadecane layer relied on molecular diffusion rather than diffusion of monomer droplets to the oil layer. Moreover, surface tension measurements confirmed that the emulsions were still in the miniemulsion regime and not in the microemulsion regime. The particle size can be tuned by controlling the duration during which the miniemulsion stayed in contact with the hexadecane layer, the interfacial area between the miniemulsion and the hexadecane layer and by the concentration of surfactant. Our method was applied to reduce the size of polystyrene and poly(methyl methacrylate) nanoparticles, nanocapsules of a copolymer of styrene and methyl methacrylic acid, and silica nanocapsules. This work demonstrated that a successful reduction of nanoparticle size in the miniemulsion process can be achieved without using excess amounts of surfactant. The method relies on building osmotic pressure in oil droplets dispersed in water which acts as semipermeable membrane.

Penetration and translocation of functional inorganic nanomaterials into biological barriers

With excellent physicochemical properties, inorganic nanomaterials (INMs) have exhibited a series of attractive applications in biomedical fields. Biological barriers prevent successful delivery of nanomedicine in living systems that limits the development of nanomedicine especially for sufficient delivery of drugs and effective therapy. Numerous researches have focused on overcoming these biological barriers and homogeneity of organisms to enhance therapeutic efficacy, however, most of these strategies fail to resolve these challenges. In this review, we present the latest progress about how INMs interact with biological barriers and penetrate these barriers. We also summarize that both native structure and components of biological barriers and physicochemical properties of INMs contributed to the penetration capacity. Knowledge about the relationship between INMs structure and penetration capacity will guide the design and application of functional and efficient nanomedicine in the future.

Synthetic Melanin Acts as Efficient Peptide Carrier in Cancer Vaccine Strategy

We previously reported that a novel peptide vaccine platform, based on synthetic melanin nanoaggregates, triggers strong cytotoxic immune responses and significantly suppresses tumor growth in mice. However, the mechanisms underlying such an efficacy remained poorly described. Herein, we investigated the role of dendritic cells (DCs) in presenting the antigen embedded in the vaccine formulation, as well as the potential stimulatory effect of melanin upon these cells, in vitro by coculture experiments and ELISA/flow cytometry analysis. The vaccine efficiency was evaluated in FLT3-L^-/- mice constitutively deficient in DC1, DC2, and pDCs, in Zbtb46^DTR chimera mice deficient in DC1 and DC2, and in Langerin^DTR mice deficient in dermal DC1 and Langerhans cells. We concluded that DCs, and especially migratory conventional type 1 dendritic cells, seem crucial for mounting the immune response after melanin-based vaccination. We also assessed the protective effect of L-DOPA melanin on peptides from enzymatic digestion, as well as the biodistribution of melanin-peptide nanoaggregates, after subcutaneous injection using [¹⁸F]MEL050 PET imaging in mice. L-DOPA melanin proved to act as an efficient carrier for peptides by fully protecting them from enzymatic degradation. L-DOPA melanin did not display any direct stimulatory effects on dendritic cells in vitro. Using PET imaging, we detected melanin-peptide nanoaggregates up to three weeks after subcutaneous injections within the secondary lymphoid tissues, which could explain the sustained immune response observed (up to 4 months) with this vaccine technology.

Ganglioside-Functionalized Nanoparticles for Chimeric Antigen Receptor T-Cell Activation at the Immunological Synapse

Chimeric Antigen Receptor (CAR) T cell therapy has proven to be an effective strategy against hematological malignancies but persistence and activity against solid tumors must be further improved. One emerging strategy for enhancing efficacy is based on directing CAR T cells to antigen presenting cells (APCs). Activation of CAR T cells at the immunological synapse (IS) formed between APC and T cell is thought to promote strong, persistent antigen-specific T cell-mediated immune responses but requires integration of CAR ligands into the APC/T-cell interface. Here, we demonstrate that CAR ligand functionalized, lipid-coated, biodegradable polymer nanoparticles (NPs) that contain the ganglioside GM3 (GM3-NPs) bind to CD169 (Siglec-1)-expressing APCs and localize to the cell contact site between APCs and CAR T cells upon initiation of cell conjugates. The CD169+ APC/CAR T-cell interface is characterized by a strong optical colocalization of GM3-NPs and CARs, enrichment of F-actin, and recruitment of ZAP-70, indicative of integration of GM3-NPs into a functional IS. Ligands associated with GM3-NPs localized to the APC/T-cell contact site remain accessible to CARs and result in robust T-cell activation. Overall, this work identifies GM3-NPs as a potential antigen delivery platform for active targeting of CD169 expressing APCs and enhancement of CAR T-cell activation at the NP-containing IS.

Short term, low dose alpha-ketoglutarate based polymeric nanoparticles with methotrexate reverse rheumatoid arthritis symptoms in mice and modulate T helper cell responses

Activated effector T cells induce pro-inflammatory responses in rheumatoid arthritis (RA) which then lead to inflammation of the joints. In this report, we demonstrate that polymeric nanoparticles with alpha keto-glutarate (aKG) in their polymer backbone (termed as paKG NPs) modulate T cell responses in vitro and in vivo. Impressively, a low dose of only three administrations of methotrexate, a clinically and chronically administered drug for RA, in conjunction with two doses of paKG NPs, reversed arthritis symptoms in collagen-induced arthritis (CIA) mice. This was further followed by significant decreases in pro-inflammatory antigen-specific T helper type 17 (TH17) responses and a significant increase in anti-inflammatory regulatory T cell (TREG) responses when CIA treated splenic cells were isolated and re-exposed to the CIA self-antigen. Overall, this study supports the concurrent and short term, low dose of paKG NPs and methotrexate for the reversal of RA symptoms.

Long-Term Vaccine Delivery and Immunological Responses Using Biodegradable Polymer-Based Carriers

Biodegradable polymers are largely employed in the biomedical field, ranging from tissue regeneration to drug/vaccine delivery. The biodegradable polymers are highly biocompatible and possess negligible toxicity. In addition, biomaterial-based vaccines possess adjuvant properties, thereby enhancing immune responses. This Review introduces the use of different biodegradable polymers and their degradation mechanism. Different kinds of vaccines, as well as the interaction between the carriers with the immune system, then are highlighted. Natural and synthetic biodegradable micro-/nanoplatforms, hydrogels, and scaffolds for local or targeted and controlled vaccine release are subsequently discussed.

Innate immune mechanisms of mRNA vaccines

The lipid nanoparticle (LNP)-encapsulated, nucleoside-modified mRNA platform has been used to generate safe and effective vaccines in record time against COVID-19. Here, we review the current understanding of the manner whereby mRNA vaccines induce innate immune activation and how this contributes to protective immunity. We discuss innate immune sensing of mRNA vaccines at the cellular and intracellular levels and consider the contribution of both the mRNA and the LNP components to their immunogenicity. A key message that is emerging from recent observations is that the LNP carrier acts as a powerful adjuvant for this novel vaccine platform. In this context, we highlight important gaps in understanding and discuss how new insight into the mechanisms underlying the effectiveness of mRNA-LNP vaccines may enable tailoring mRNA and carrier molecules to develop vaccines with greater effectiveness and milder adverse events in the future.

Recent Advances in Delivery Systems for Genetic and Other Novel Vaccines

Vaccination is one of the most successful and cost-effective prophylactic measures against diseases, especially infectious diseases including smallpox and polio. However, the development of effective prophylactic or therapeutic vaccines for other diseases such as cancer remains challenging. This is often due to the imprecise control of vaccine activity in vivo which leads to insufficient/inappropriate immune responses or short immune memory. The development of new vaccine types in recent decades has created the potential for improving the protective potency against these diseases. Genetic and subunit vaccines are two major categories of these emerging vaccines. Owing to their nature, they rely heavily on delivery systems with various functions, such as effective cargo protection, immunogenicity enhancement, targeted delivery, sustained release of antigens, selective activation of humoral and/or cellular immune responses against specific antigens, and reduced adverse effects. Therefore, vaccine delivery systems may significantly affect the final outcome of genetic and other novel vaccines and are vital for their development. This review introduces these studies based on their research emphasis on functional design or administration route optimization, presents recent progress, and discusses features of new vaccine delivery systems, providing an overview of this field.

Multifunctional plant virus nanoparticles in the next generation of cancer immunotherapies

Plant virus nanoparticles (PVNPs) have inherent immune stimulatory ability, and have been investigated as immune adjuvants to stimulate an anti-tumor immune response. The combination of immune stimulation, nanoparticle structure and the ability to deliver other therapeutic molecules provides a flexible platform for cancer immunotherapy. Researching multifunctional PVNPs and their modification will generate novel reagents for cancer immunotherapy. Here we review the properties of PVNPs, and their potential for clinical utilization to activate anti-tumor innate and lymphoid immune responses. PVNPs have potential utility for cancer immunotherapy as vaccine adjuvant, and delivery systems for other reagents as mono immunotherapy or combined with other immunotherapies. This review outlines the potential and challenges in developing PVNPs as cancer immunotherapy reagents.

Evaluation of Adjuvant Activity and Bio-Distribution of Archaeosomes Prepared Using Microfluidic Technology

Archaeosomes, composed of sulfated lactosyl archaeol (SLA) glycolipids, have been proven to be an effective vaccine adjuvant in multiple preclinical models of infectious disease or cancer. They have classically been prepared using a thin-film hydration method with an average particle size of 100-200 nm. In this study, we developed methods to generate SLA archaeosomes at different sizes, i.e., 30 nm and 100 nm, via microfluidic mixing technology and evaluated their physicochemical characteristics, as well as adjuvant activity and in vivo biodistribution in mice. Archaeosomes, prepared using thin-film and microfluidic mixing techniques, had similar nanostructures and physicochemical characteristics, with both appearing stable during the course of this study when stored at 4 °C or 37 °C. They also demonstrated similar adjuvant activity when admixed with ovalbumin antigen and used to immunize mice, generating equivalent antigen-specific immune responses. Archaeosomes, labeled with CellVueTM NIR815, had an equivalent biodistribution with both sizes, namely the highest signal at the injection site at 24 h post injection, followed by liver, spleen and inguinal lymph node. The presence of SLA archaeosomes of either size helped to retain OVA antigen (OVA-Cy5.5) longer at the injection site than unadjuvanted OVA. Overall, archaeosomes of two sizes (30 nm and 100 nm) prepared using microfluidic mixing maintained similar physicochemical properties, adjuvant activity and biodistribution of antigen, in comparison to those compared by the conventional thin film hydration method. This suggests that microfluidics based approaches could be applied to generate consistently sized archaeosomes for use as a vaccine adjuvant.

How promising are HIV-1-based virus-like particles for medical applications

New approaches aimed at identifying patient-specific drug targets and addressing unmet clinical needs in the framework of precision medicine are a strong motivation for researchers worldwide. As scientists learn more about proteins that drive known diseases, they are better able to design promising therapeutic approaches to target those proteins. The field of nanotechnology has been extensively explored in the past years, and nanoparticles (NPs) have emerged as promising systems for target-specific delivery of drugs. Virus-like particles (VLPs) arise as auspicious NPs due to their intrinsic properties. The lack of viral genetic material and the inability to replicate, together with tropism conservation and antigenicity characteristic of the native virus prompted extensive interest in their use as vaccines or as delivery systems for therapeutic and/or imaging agents. Owing to its simplicity and non-complex structure, one of the viruses currently under study for the construction of VLPs is the human immunodeficiency virus type 1 (HIV-1). Typically, HIV-1-based VLPs are used for antibody discovery, vaccines, diagnostic reagent development and protein-based assays. This review will be centered on the use of HIV-1-based VLPs and their potential biomedical applications.

Contributions of PD-L1 reverse signaling to dendritic cell trafficking

Programmed death-1 (PD-1)/programmed death-ligand 1 (PD-L1) interactions are critical for dampening the immune response to both self and foreign antigens. The signaling of PD-L1 via its cytoplasmic domain, rather than through its interactions with PD-1 via the extracellular domain, has been termed PD-L1 reverse signaling. While this signaling is beneficial for cancer progression, little is understood about the consequences of PD-L1 reverse signaling in immune cells that express PD-L1 at steady state or in response to infection. Loss of PD-L1 during infection leads to unchecked T-cell proliferation and increased autoimmune T-cell responses. While the T-cell intrinsic role of PD-1 for inhibiting T-cell responses has been well explored, little to no effort has been directed at investigating the consequences of PD-L1 reverse signaling on the DCs interacting with PD-1+ T cells. We recently reported a defect in dendritic cell (DC) trafficking from the skin to the draining lymph node (LN) following immunization or infection in the absence of PD-L1. We demonstrated that a region within the cytoplasmic tail was responsible for the defect in DC trafficking. Here, we review the processes involved in DC trafficking and highlight what we know about PD-L1 expression, PD-L1 post-translational modifications, PD-L1 intracellular interactions, and PD-L1 extracellular interactions.

A proposed mathematical description of in vivo nanoparticle delivery

Nanoparticles are promising vehicles for the precise delivery of molecular therapies to diseased sites. Nanoparticles interact with a series of tissues and cells before they reach their target, which causes less than 1% of administered nanoparticles to be delivered to these target sites. Researchers have been studying the nano-bio interactions that mediate nanoparticle delivery to develop guidelines for designing nanoparticles with enhanced delivery properties. In this review article, we describe these nano-bio interactions with a series of mathematical equations that quantitatively define the nanoparticle delivery process. We employ a compartment model framework to describe delivery where nanoparticles are either (1) at the site of administration, (2) in the vicinity of target cells, (3) internalized by the target cells, or (4) sequestered away in off-target sites or eliminated from the body. This framework explains how different biological processes govern nanoparticle transport between these compartments, and the role of intercompartmental transport rates in determining the final nanoparticle delivery efficiency. Our framework provides guiding principles to engineer nanoparticles for improved targeted delivery.

Nano toolbox in immune modulation and nanovaccines

Despite the great success of vaccines over two centuries, the conventional strategy is based on attenuated/altered microorganisms. However, this is not effective for all microbes and often fails to elicit a protective immune response, and sometimes poses unexpected safety risks. The expanding nano toolbox may overcome some of the roadblocks in vaccine development given the plethora of unique nanoparticle (NP)-based platforms that can successfully induce specific immune responses leading to exciting and novel solutions. Nanovaccines necessitate a thorough understanding of the immunostimulatory effect of these nanotools. We present a comprehensive description of strategies in which nanotools have been used to elicit an immune response and provide a perspective on how nanotechnology can lead to future personalized nanovaccines.

Novel Proteoliposome-Based Vaccine against E. coli: A Potential New Tool for the Control of Bovine Mastitis

Simple Summary

Mastitis is a highly prevalent disease in dairy cattle, affecting animal welfare and generating economic losses for the dairy industry. Control measures for coliform mastitis are limited, due to the constant exposure of the teat to bacteria and the emergence of antimicrobial-resistant bacteria, making vaccination an important strategy for control of mastitis. However, currently available vaccines show limited efficacy, which could be attributed to inactivation processes that alter the antigenic preservation of the vaccines. The aim of this study was to assess the efficacy of a novel vaccine against mastitis using proteoliposomes obtained from E. coli in a murine model of coliform mastitis. We demonstrated that the proteoliposome vaccine was safe, immunogenic and effective against an experimental model of E. coli mastitis, decreasing bacterial count and tissue damage. This proteoliposome vaccine is a potential new tool for prevention of mastitis.

Abstract

Escherichia coli is an important causative agent of clinical mastitis in cattle. Current available vaccines have shown limited protection. We evaluated the efficacy of a novel vaccine based on bacterial proteoliposomes derived from an E. coli field strain. Female BALB/c mice were immunized subcutaneously with two doses of the vaccine, 3 weeks apart. Between days 5 and 8 after the first inoculation, the females were mated. At 5–8 days postpartum, the mice were intramammary challenged with the same E. coli strain. Two days after bacterial infection, mice were euthanized, and the mammary glands were examined and removed to evaluate the efficacy and safety of the vaccine as well as the immune response generated by the new formulation. The vaccinated mice showed mild clinical symptoms and a lower mammary bacterial load as compared to non-vaccinated animals. The vaccination induced an increase in levels of IgG, IgG1 and IgG2a against E. coli in blood and mammary glands that showed less inflammatory infiltration and tissue damage, as compared to the control group. In summary, the vaccine based on bacterial proteoliposomes is safe, immunogenic, and effective against E. coli, constituting a new potential tool for mastitis control.

Current knowledge on the tissue distribution of mRNA nanocarriers for therapeutic protein expression

Exogenously delivered mRNA-based drugs are emerging as a new class of therapeutics with the potential to treat several diseases. Over the last decade, advancements in the design of non-viral delivery tools have enabled mRNA to be evaluated for several therapeutic purposes including protein replacement therapies, gene editing, and vaccines. However, in vivo delivery of mRNA to targeted organs and cells remains a critical challenge. Evaluation of the biodistribution of mRNA vehicles is of utmost importance for the development of effective pharmaceutical candidates. In this review, we discuss the recent advances in the design of nanoparticles loaded with mRNA and extrapolate the key factors influencing their biodistribution following administration. Finally, we highlight the latest developments in the preclinical and clinical translation of mRNA therapeutics for protein supplementation therapy.

Nanomaterials and Advances in Tumor Immune-Related Therapy: A Bibliometric Analysis

With the rapid growth of the research content of nanomaterials and tumor immunity, the hot spots and urgent problems in the field become blurred. In this review, noticing the great development potential of this research field, we collected and sorted out the research articles from The Clarivate Analytics Web of Science (WOS) Core Collection database in the field over the past 20 years. Next, we use Excel 2019 from Microsoft (Microsoft Corp, Redmond,WA, USA), VOSviewer (version 1.6.18, Leiden University, Leiden, Netherlands), CiteSpace (Chaomei Chen, Drexel University, USA) and other softwares to conduct bibliometric analysis on the screened literatures. This paper not only analyzes the countries, institutions and authors with outstanding contributions in the current research field, but also comes up with the hot spots of current research. We hope that by analyzing and sorting out the past data, we can provide help for the current clinical work and future scientific research.

Mesoporous Silica Materials as an Emerging Tool for Cancer Immunotherapy

Cancer immunotherapy has emerged in the past decade as a promising strategy for treating many forms of cancer by stimulating the patient's immune system. Although immunotherapy has achieved some promising results in clinics, more efforts are required to improve the limitations of current treatments related to lack of effective and targeted cancer antigens delivery to immune cells, dose-limiting toxicity, and immune-mediated adverse effects, among others. In recent years, the use of nanomaterials has proven promising to enhance cancer immunotherapy efficacy and reduce side effects. Among nanomaterials, attention has been recently paid to mesoporous silica nanoparticles (MSNs) as a potential multiplatform for enhancing cancer immunotherapy by considering their unique properties, such as high porosity, and good biocompatibility, facile surface modification, and self-adjuvanticity. This review explores the role of MSN and other nano/micro-materials as an emerging tool to enhance cancer immunotherapy, and it comprehensively summarizes the different immunotherapeutic strategies addressed to date by using MSN.

Tumor-Targeted Polydopamine-Based Nanoparticles for Multimodal Mapping Following Photothermal Therapy of Metastatic Lymph Nodes

Purpose

Lymphadenectomy with lymph node (LN) mapping is essential for surgical removal of solid tumors. Existing agents do not provide accurate multimodal mapping and antitumor therapy for metastatic LNs; therefore, we fabricated a polydopamine (PDA) nanoparticle (NP)-based tumor-targeted LN mapping agent capable of multimodal mapping and guided photothermal therapy (PTT) for metastatic LNs.

Materials and Methods

PDA NPs modified with polyethylene glycol (PEG) were obtained by polymerization under alkaline conditions. The PEG-PDA NPs were loaded with the circular tripeptide Arg-Gly-Asp (cRGD) to achieve tumor-targeting capacity and with the fluorescent dye IR820 and magnetic resonance imaging (MRI) contrast Gd(NH₂)₂ for in situ detection. The resulting cRGD-PEG-PDA@IR820/Gd(NH₂)₂ (cRGD-PPIG) NPs were tested for their biosafety and metastatic LN mapping ability. They were drained specifically into LNs and selectively taken up by gastric MKN45 cells via α_vβ3 integrin-mediated endocytosis.

Results

This phenomenon enabled MR/optical/near-infrared fluorescence multimodal metastatic LN mapping, guiding the creation of accurate and highly efficient PTT for gastric cancer metastatic LNs in mice.

Conclusion

In summary, we fabricated tumor-targeted cRGD-PPIG NPs with MR/optical/near-infrared fluorescence multimodal metastatic LN mapping capacity for surgery and efficient PTT guidance post-surgery.

Cutting-Edge Delivery Systems and Adjuvants in Tolerogenic Vaccines: A Review

Conventional therapies for immune-mediated diseases, including autoimmune disorders, transplant reactions, and allergies, have undergone a radical evolution in the last few decades; however, they are still not specific enough to avoid widespread immunosuppression. The idea that vaccine usage could be extended beyond its traditional immunogenic function by encompassing the ability of vaccines to induce antigen-specific tolerance may revolutionize preventive and therapeutic strategies in several clinical fields that deal with immune-mediated disorders. This approach has been supported by improved data relating to the several mechanisms involved in controlling unwanted immune responses and allowing peripheral tolerance. Given these premises, several approaches have been developed to induce peripheral tolerance against the antigens that are involved in the pathological immune response, including allergens, autoantigens, and alloantigens. Technological innovations, such as nucleic acid manipulation and the advent of micro- and nanoparticles, have further supported these novel preventive and therapeutic approaches. This review focuses on the main strategies used in the development of tolerogenic vaccines, including the technological issues used in their design and the role of “inverse adjuvants”. Even though most studies are still limited to the preclinical field, the enthusiasm generated by their results has prompted some initial clinical trials, and they show great promise for the future management of immune-mediated pathological conditions.

Breast cancer vaccines: New insights into immunomodulatory and nano-therapeutic approaches

Breast cancer (BC) is known to be a highly heterogeneous disease that is clinically subdivided into four primary molecular subtypes, each having distinct morphology and clinical implications. These subtypes are principally defined by hormone receptors and other proteins involved (or not involved) in BC development. BC therapeutic vaccines [including peptide-based vaccines, protein-based vaccines, nucleic acid-based vaccines (DNA/RNA vaccines), bacterial/viral-based vaccines, and different immune cell-based vaccines] have emerged as an appealing class of cancer immunotherapeutics when used alone or combined with other immunotherapies. Employing the immune system to eliminate BC cells is a novel therapeutic modality. The benefit of active immunotherapies is that they develop protection against neoplastic tissue and readjust the immune system to an anti-tumor monitoring state. Such immunovaccines have not yet shown effectiveness for BC treatment in clinical trials. In recent years, nanomedicines have opened new windows to increase the effectiveness of vaccinations to treat BC. In this context, some nanoplatforms have been designed to efficiently deliver molecular, cellular, or subcellular vaccines to BC cells, increasing the efficacy and persistence of anti-tumor immunity while minimizing undesirable side effects. Immunostimulatory nano-adjuvants, liposomal-based vaccines, polymeric vaccines, virus-like particles, lipid/calcium/phosphate nanoparticles, chitosan-derived nanostructures, porous silicon microparticles, and selenium nanoparticles are among the newly designed nanostructures that have been used to facilitate antigen internalization and presentation by antigen-presenting cells, increase antigen stability, enhance vaccine antigenicity and remedial effectivity, promote antigen escape from the endosome, improve cytotoxic T lymphocyte responses, and produce humoral immune responses in BC cells. Here, we summarized the existing subtypes of BC and shed light on immunomodulatory and nano-therapeutic strategies for BC vaccination. Finally, we reviewed ongoing clinical trials on BC vaccination and highlighted near-term opportunities for moving forward.

A nanoparticle-based COVID-19 vaccine candidate elicits broad neutralizing antibodies and protects against SARS-CoV-2 infection

A vaccine candidate to SARS-CoV-2 was constructed by coupling the viral receptor binding domain (RBD) to the surface of the papaya mosaic virus (PapMV) nanoparticle (nano) to generate the RBD-PapMV vaccine. Immunization of mice with the coupled RBD-PapMV vaccine enhanced the antibody titers and the T-cell mediated immune response directed to the RBD antigen as compared to immunization with the non-coupled vaccine formulation (RBD + PapMV nano). Anti-RBD antibodies, generated in vaccinated animals, neutralized SARS-CoV-2 infection in vitro against the ancestral, Delta and the Omicron variants. At last, immunization of mice susceptible to the infection by SARS-CoV-2 (K18-hACE2 transgenic mice) with the RBD-PapMV vaccine induced protection to the ancestral SARS-CoV-2 infectious challenge. The induction of the broad neutralization against SARS-CoV-2 variants induced by the RBD-PapMV vaccine demonstrate the potential of the PapMV vaccine platform in the development of efficient vaccines against viral respiratory infections.

Progress towards the Development of a Universal Influenza Vaccine

Influenza viruses are responsible for millions of cases globally and significantly threaten public health. Since pandemic and zoonotic influenza viruses have emerged in the last 20 years and some of the viruses have resulted in high mortality in humans, a universal influenza vaccine is needed to provide comprehensive protection against a wide range of influenza viruses. Current seasonal influenza vaccines provide strain-specific protection and are less effective against mismatched strains. The rapid antigenic drift and shift in influenza viruses resulted in time-consuming surveillance and uncertainty in the vaccine protection efficacy. Most recent universal influenza vaccine studies target the conserved antigen domains of the viral surface glycoproteins and internal proteins to provide broader protection. Following the development of advanced vaccine technologies, several innovative strategies and vaccine platforms are being explored to generate robust cross-protective immunity. This review provides the latest progress in the development of universal influenza vaccines.

Immunogenicity Risk Assessment of Spontaneously Occurring Therapeutic Monoclonal Antibody Aggregates

Aggregates of therapeutic proteins have been associated with increased immunogenicity in pre-clinical models as well as in human patients. Recent studies to understand aggregates and their immunogenicity risks use artificial stress methods to induce high levels of aggregation. These methods may be less biologically relevant in terms of their quantity than those that occur spontaneously during processing and storage. Here we describe the immunogenicity risk due to spontaneously occurring therapeutic antibody aggregates using peripheral blood mononuclear cells (PBMC) and a cell line with a reporter gene for immune activation: THP-1 BLUE NFκB. The spontaneously occurring therapeutic protein aggregates were obtained from process intermediates and final formulated drug substance from stability retains. Spontaneously occurring aggregates elicited innate immune responses for several donors in a PBMC assay with cytokine and chemokine production as a readout for immune activation. Meanwhile, no significant adaptive phase responses to spontaneously occurring aggregate samples were detected. While the THP-1 BLUE NFκB cell line and PBMC assays both responded to high stress induced aggregates, only the PBMC from a limited subset of donors responded to processing-induced aggregates. In this case study, levels of antibody aggregation occurring at process relevant levels are lower than those induced by stirring and may pose lower risk in vivo. Our methodologies can further inform additional immunogenicity risk assessments using a pre-clinical in vitro risk assessment approach utilizing human derived immune cells.

Nanotechnology-facilitated vaccine development during the coronavirus disease 2019 (COVID-19) pandemic

Coronavirus disease 2019 (COVID-19) continually poses a significant threat to the human race, and prophylactic vaccination is the most potent approach to end this pandemic. Nanotechnology is widely adopted during COVID-19 vaccine development, and the engineering of nanostructured materials such as nanoparticles has opened new possibilities in innovative vaccine development by improving the design and accelerating the development process. This review aims to comprehensively understand the current situation and prospects of nanotechnology-enabled vaccine development against the COVID-19 pandemic, with an emphasis on the interplay between nanotechnology and the host immune system.

The Big Potential of Small Particles: Lipid-Based Nanoparticles and Exosomes in Vaccination

Some of the most significant medical achievements in recent history are the development of distinct and effective vaccines, and the improvement of the efficacy of previously existing ones, which have contributed to the eradication of many dangerous and life-threatening diseases. Immunization depends on the generation of a physiological memory response and protection against infection. It is therefore crucial that antigens are delivered in an efficient manner, to elicit a robust immune response. The recent approval of COVID-19 vaccines containing lipid nanoparticles encapsulating mRNA demonstrates the broad potential of lipid-based delivery systems. In light of this, the present review article summarizes currently synthesized lipid-based nanoparticles such as liposomes, lipid-nano particles, or cell-derived exosomes.

Nano-bio interactions: A major principle in the dynamic biological processes of nano-assemblies

Controllable nano-assembly with stimuli-responsive groups is emerging as a powerful strategy to generate theranostic nanosystems that meet unique requirements in modern medicine. However, this prospective field is still in a proof-of-concept stage due to the gaps in our understanding of complex-(nano-assemblies)-complex-(biosystems) interactions. Indeed, stimuli-responsive assembly-disassembly is, in and of itself, a process of nano-bio interactions, the key steps for biological fate and functional activity of nano-assemblies. To provide a comprehensive understanding of these interactions in this review, we first propose a 4W1H principle (Where, When, What, Which and How) to delineate the relevant dynamic biological processes, behaviour and fate of nano-assemblies. We further summarize several key parameters that govern effective nano-bio interactions. The effects of these kinetic parameters on ADMET processes (absorption, distribution, metabolism, excretion and transformation) are then discussed. Furthermore, we provide an overview of the challenges facing the evaluation of nano-bio interactions of assembled nanodrugs. We finally conclude with future perspectives on safe-by-design and application-driven-design of nano-assemblies. This review will highlight the dynamic biological and physicochemical parameters of nano-bio interactions and bridge discrete concepts to build a full spectrum understanding of the biological outcomes of nano-assemblies. These principles are expected to pave the way for future development and clinical translation of precise, safe and effective nanomedicines with intelligent theranostic features.

Extrahepatic targeting of lipid nanoparticles in vivo with intracellular targeting for future nanomedicines

A new era of nanomedicines that involve nucleic acids/gene therapy has been opened after two decades in 21^st century and new types of more efficient drug delivery systems (DDS) are highly expected and will include extrahepatic delivery. In this review, we summarize the possibility and expectations for the extrahepatic delivery of small interfering RNA/messenger RNA/plasmid DNA/genome editing to the spleen, lung, tumor, lymph nodes as well as the liver based on our studies as well as reported information. Passive targeting and active targeting are discussed in in vivo delivery and the importance of controlled intracellular trafficking for successful therapeutic results are also discussed. In addition, mitochondrial delivery as a novel strategy for nucleic acids/gene therapy is introduced to expand the therapeutic dimension of nucleic acids/gene therapy in the liver as well as the heart, kidney and brain.