Gold nanoparticles as a vaccine platform: influence of size and shape on immunological responses in vitro and in vivo

Nanomedicine as a Promising Tool to Overcome Immune Escape in Breast Cancer

Breast cancer is the most common type of malignancy and leading cause of cancer death among women worldwide. Despite the current revolutionary advances in the field of cancer immunotherapy, clinical response in breast cancer is frequently below expectations, in part due to various mechanisms of cancer immune escape that produce tumor variants that are resistant to treatment. Thus, a further understanding of the molecular events underlying immune evasion in breast cancer may guarantee a significant improvement in the clinical success of immunotherapy. Furthermore, nanomedicine provides a promising opportunity to enhance the efficacy of cancer immunotherapy by improving the delivery, retention and release of immunostimulatory agents in targeted cells and tumor tissues. Hence, it can be used to overcome tumor immune escape and increase tumor rejection in numerous malignancies, including breast cancer. In this review, we summarize the current status and emerging trends in nanomedicine-based strategies targeting cancer immune evasion and modulating the immunosuppressive tumor microenvironment, including the inhibition of immunosuppressive cells in the tumor area, the activation of dendritic cells and the stimulation of the specific antitumor T-cell response.

Nano dimensions/adjuvants in COVID-19 vaccines

A favorable outcome of the COVID-19 crisis might be achieved with massive vaccination. The proposed vaccines contain several different vaccine active principles (VAP), such as inactivated virus, antigen, mRNA, and DNA, which are associated with either standard adjuvants or nanomaterials (NM) such as liposomes in Moderna's and BioNTech/Pfizer's vaccines. COVID-19 vaccine adjuvants may be chosen among liposomes or other types of NM composed for example of graphene oxide, carbon nanotubes, micelles, exosomes, membrane vesicles, polymers, or metallic NM, taking inspiration from cancer nano-vaccines, whose adjuvants may share some of their properties with those of viral vaccines. The mechanisms of action of nano-adjuvants are based on the facilitation by NM of targeting certain regions of immune interest such as the mucus, lymph nodes, and zones of infection or blood irrigation, the possible modulation of the type of attachment of the VAP to NM, in particular VAP positioning on the NM external surface to favor VAP presentation to antigen presenting cells (APC) or VAP encapsulation within NM to prevent VAP degradation, and the possibility to adjust the nature of the immune response by tuning the physico-chemical properties of NM such as their size, surface charge, or composition. The use of NM as adjuvants or the presence of nano-dimensions in COVID-19 vaccines does not only have the potential to improve the vaccine benefit/risk ratio, but also to reduce the dose of vaccine necessary to reach full efficacy. It could therefore ease the overall spread of COVID-19 vaccines within a sufficiently large portion of the world population to exit the current crisis.

Active targeting via ligand-anchored pH-responsive strontium nanoparticles for efficient nucleic acid delivery into breast cancer cells

Purpose

Gene therapy is a promising and novel therapeutic strategy for many mutated gene-associated diseases, including breast cancer. However, it poses significant biological drawbacks such as rapid clearance from the circulatory system and low cellular uptake of the exogenously delivered functional nucleic acids. The development of efficient and biocompatible carriers for genetic materials has been extensively explored in the literature, and the functionalization of nanoparticles (NPs) with cancer cell-recognizing ligands has become an attractive approach to promote tumor targetability and efficient cellular internalization via endocytosis.

Methods

This study introduced self-assembling targeting ligands, including transferrin and fibronectin with the ability to electrostatically interact with strontium nanoparticles (SNPs), and then analyzed their influence on size and zeta potential of the resultant hybrid SNPs, cellular uptake and expression efficiency of transgene-loaded hybrid NPs.

Results

Smaller ligand-coated SNPs (LCSNPs) remarkably increased gene transfection activity in both MCF-7 and 4T1 cells as well as nucleic acid localization into tumor tissues with improved tumor regression activity in a 4T1-tumor xenograft mouse model.

Conclusion

LCSNPs-mediated delivery of p53 gene and MAPK siRNA provided a proof-of-concept for the functionalized nanocarrier formulation in order to inhibit breast cancer cell growth.

A Nanoscale Shape-Discovery Framework Supporting Systematic Investigations of Shape-Dependent Biological Effects and Immunomodulation

Since it is now possible to make, in a controlled fashion, an almost unlimited variety of nanostructure shapes, it is of increasing interest to understand the forms of biological control that nanoscale shape allows. However, a priori rational investigation of such a vast universe of shapes appears to present intractable fundamental and practical challenges. This has limited the useful systematic investigation of their biological interactions and the development of innovative nanoscale shape-dependent therapies. Here, we introduce a concept of biologically relevant inductive nanoscale shape discovery and evaluation that is ideally suited to, and will ultimately become, a vehicle for machine learning discovery. Combining the reproducibility and tunability of microfluidic flow nanochemistry syntheses, quantitative computational shape analysis, and iterative feedback from biological responses in vitro and in vivo, we show that these challenges can be mastered, allowing shape biology to be explored within accepted scientific and biomedical research paradigms. Early applications identify significant forms of shape-induced biological and adjuvant-like immunological control.

Anticancer Vaccination with Immunogenic Micelles That Capture and Release Pristine CD8+ T-Cell Epitopes and Adjuvants

The development of nanocarriers capable of codelivering antigens and immune-activating adjuvants is an emerging area of research and is relevant for cancer vaccines that target induction of antigen-specific CD8⁺ T-cell responses. Here, we report a system for delivery of short peptide antigens to dendritic cells for strong cellular immune responses, based on block copolymers chemically modified with a hydrophobic and self-immolative linker. After modification, micelles effectively and reversibly capture antigens and adjuvants via a covalent bond within several minutes in an aqueous solution. After uptake in antigen presenting cells, the polymer disulfide bond is cleaved by intracellular glutathione, leading to release of pristine antigens, along with the upregulated expression of costimulatory molecules. The induced antigen-specific CD8⁺ T cells have strong tumor cell killing efficacy in the murine B16OVA and human papilloma virus-E6/E7 subcutaneous and lung metastasis tumor models. In addition, delivery to lymph nodes can be imaged to visualize vaccine trafficking. Taken together, multifunctional self-immolative micelles represent a versatile class of a vaccine delivery system for the generation of a cellular immune response that warrants further exploration as a component of cancer immunotherapy.

Multifunctional inorganic nanomaterials for cancer photoimmunotherapy

Phototherapy and immunotherapy in combination is regarded as the ideal therapeutic modality to treat both primary and metastatic tumors. Immunotherapy uses different immunological approaches to stimulate the immune system to identify tumor cells for targeted elimination. Phototherapy destroys the primary tumors by light irradiation, which induces a series of immune responses through triggering immunogenic cancer cell death. Therefore, when integrating immunotherapy with phototherapy, a novel anti-cancer strategy called photoimmunotherapy (PIT) is emerging. This synergistic treatment modality can not only enhance the effectiveness of both therapies but also overcome their inherent limitations, opening a new era for the current anti-cancer therapy. Recently, the advancement of nanomaterials affords a platform for PIT. From all these nanomaterials, inorganic nanomaterials stand out as ideal mediators in PIT due to their unique physiochemical properties. Inorganic nanomaterials can not only serve as carriers to transport immunomodulatory agents in immunotherapy owing to their excellent drug-loading capacity but also function as photothermal agents or photosensitizers in phototherapy because of their great optical characteristics. In this review, the recent advances of multifunctional inorganic nanomaterial-mediated drug delivery and their contributions to cancer PIT will be highlighted.

Nanomaterials with changeable physicochemical property for boosting cancer immunotherapy

The past decade has witnessed a great progress in cancer immunotherapy with the sequential approvals of therapeutic cancer vaccine, immune checkpoint inhibitor and chimeric antigen receptor (CAR) T cell therapy. However, some hurdles still remain to the wide implementation of cancer immunotherapy, including low immune response, complex tumor heterogeneity, off-target immunotoxicity, poor solid tumor infiltration, and immune evasion-induced treatment tolerance. Owing to changeable physicochemical properties in response to endogenous or exogenous stimuli, nanomaterials hold the remarkable potential in incorporation of multiple agents, efficient biological barrier penetration, precise immunomodulator delivery, and controllable content release for boosting cancer immunotherapy. Herein, we review the recent advances in nanomaterials with changeable physicochemical property (NCPP) to develop cancer vaccine, remold tumor microenvironment and evoke direct T cell activation. Besides, we provide our outlook on this emerging field at the intersection of NCPP design and cancer immunotherapy.

Lactoferrin-Functionalized Noble Metal Nanoparticles as New Antivirals for HSV-2 Infection

(1) Background: Lactoferrin has been recognized as a potent inhibitor of human herpetic viruses, such as herpes simplex type 1 (HSV-1) and 2 (HSV-2). In this work, we tested if silver and gold nanoparticles modified with lactoferrin (LF-Ag/AuNPs) can become novel microbicides with additional adjuvant properties to treat genital herpes infection. (2) Methods: The antiviral and cytotoxic activities of LF-Ag/AuNPs were tested in human skin HaCaT and vaginal VK-2-E6/E7 keratinocytes. Viral titers and immune responses after treatment with LF-Ag/AuNPs were tested in murine vaginal HSV-2 infection. (3) Results: LF-Ag/AuNPs inhibited attachment and entry of HSV-2 in human keratinocytes much better than lactoferrin. Furthermore, pretreatment with LF-AgNPs led to protection from infection. Infected mice treated intravaginally with LF-Ag/AuNPs showed lower virus titers in the vaginal tissues and spinal cords in comparison to treatment with lactoferrin. Following treatment, vaginal tissues showed a significant increase in CD8+/granzyme B + T cells, NK cells and dendritic cells in comparison to NaCl-treated group. LF-Ag/AuNPs-treated animals also showed significantly better expression of IFN-γ, CXCL9, CXCL10, and IL-1β in the vaginal tissues. (4) Conclusions: Our findings show that LF-Ag/AuNPs could become effective novel antiviral microbicides with immune-stimulant properties to be applied upon the mucosal tissues.

Immuno-modulatory biomaterials as anti-inflammatory therapeutics

Biocompatible and biodegradable biomaterials are used extensively in regenerative medicine and serve as a tool for tissue replacement, as a platform for regeneration of injured tissue, and as a vehicle for delivery of drugs. One of the key factors that must be addressed in developing successful biomaterial-based therapeutics is inflammation. Whilst inflammation is initially essential for wound healing; bringing about clearance of debris and infection, prolonged inflammation can result in delayed wound healing, rejection of the biomaterial, further tissue damage and increased scarring and fibrosis. In this context, the choice of biomaterial must be considered carefully to minimise further induction of inflammation. Here we address the ability of the biomaterials themselves to modulate inflammatory responses and outline how the physico-chemical properties of the materials impact on their pro and anti-inflammatory properties (Fig. 1).

Nanoparticle/Nanocarrier Formulation as an Antigen: The Immunogenicity and Antigenicity of Itself

In antibody preparation, the immunogenicity of small molecules is limited due to the instability of adjuvant/hapten emulsions. Nanoparticle-based adjuvants overcome instability and effectively improve immune responses. Immunogenicity and antigenicity are fundamentally important, yet understudied, facets of nanoparticle formulations themselves. Herein, we studied the immunogenicity and antigenicity of nanoparticle formulations. In experiments in a rabbit model, simple inorganic nanoparticle (e.g., gold nanoparticle (AuNP) and silver nanoparticle (AgNP)) immunogens induced higher titers of antiserum. Moreover, several promising nanoparticle drug carrier immunogens (e.g., SiO₂, oleylamine graft polysuccinimide (PSI_OAm), oleylamine and N-(3-aminopropyl)imidazole cograft polysuccinimide (PSI_OAm-NAPI), Fe₃O₄@O-dextran, etc.) showed excellent immunogenicity. Cross-reactivity calculations revealed that the antigenicity properties of AgNP and AuNP antigens are highly size-dependent. Meanwhile, four nanoparticle drug carriers generate antibody-specific immune responses to their antigens. The reactivity of the anti-NP antibodies with nanoparticle antigens was confirmed using immunoassays. This study systematically identified the immunogenicity and antigenicity of the nanoparticle formulation itself. These findings provide insights into the immunological properties of the nanoparticle formulation itself in an organism.

Antitumor Peptide-Based Vaccine in the Limelight

The success of the immune checkpoint blockade has provided a proof of concept that immune cells are capable of attacking tumors in the clinic. However, clinical benefit is only observed in less than 20% of the patients due to the non-specific activation of immune cells by the immune checkpoint blockade. Developing tumor-specific immune responses is a challenging task that can be achieved by targeting tumor antigens to generate tumor-specific T-cell responses. The recent advancements in peptide-based immunotherapy have encouraged clinicians and patients who are struggling with cancer that is otherwise non-treatable with current therapeutics. By selecting appropriate epitopes from tumor antigens with suitable adjuvants, peptides can elicit robust antitumor responses in both mice and humans. Although recent experimental data and clinical trials suggest the potency of tumor reduction by peptide-based vaccines, earlier clinical trials based on the inadequate hypothesis have misled that peptide vaccines are not efficient in eliminating tumor cells. In this review, we highlighted the recent evidence that supports the rationale of peptide-based antitumor vaccines. We also discussed the strategies to select the optimal epitope for vaccines and the mechanism of how adjuvants increase the efficacy of this promising approach to treat cancer.

Biomaterial-assisted biotherapy: A brief review of biomaterials used in drug delivery, vaccine development, gene therapy, and stem cell therapy

Biotherapy has recently become a hotspot research topic with encouraging prospects in various fields due to a wide range of treatments applications, as demonstrated in preclinical and clinical studies. However, the broad applications of biotherapy have been limited by critical challenges, including the lack of safe and efficient delivery systems and serious side effects. Due to the unique potentials of biomaterials, such as good biocompatibility and bioactive properties, biomaterial-assisted biotherapy has been demonstrated to be an attractive strategy. The biomaterial-based delivery systems possess sufficient packaging capacity and versatile functions, enabling a sustained and localized release of drugs at the target sites. Furthermore, the biomaterials can provide a niche with specific extracellular conditions for the proliferation, differentiation, attachment, and migration of stem cells, leading to tissue regeneration. In this review, the state-of-the-art studies on the applications of biomaterials in biotherapy, including drug delivery, vaccine development, gene therapy, and stem cell therapy, have been summarized. The challenges and an outlook of biomaterial-assisted biotherapies have also been discussed.

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Biomaterials possess unique advantages to improve the efficacy and safety of biotherapy.

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Various types of biomaterials can be used in a wide range of biotherapy.

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The functions of biomaterials can be tuned by changing their inherent properties or the surrounding environment.

Review: Development of SARS-CoV-2 immuno-enhanced COVID-19 vaccines with nano-platform

Vaccination is the most effective way to prevent coronavirus disease 2019 (COVID-19). Vaccine development approaches consist of viral vector vaccines, DNA vaccine, RNA vaccine, live attenuated virus, and recombinant proteins, which elicit a specific immune response. The use of nanoparticles displaying antigen is one of the alternative approaches to conventional vaccines. This is due to the fact that nano-based vaccines are stable, able to target, form images, and offer an opportunity to enhance the immune responses. The diameters of ultrafine nanoparticles are in the range of 1-100 nm. The application of nanotechnology on vaccine design provides precise fabrication of nanomaterials with desirable properties and ability to eliminate undesirable features. To be successful, nanomaterials must be uptaken into the cell, especially into the target and able to modulate cellular functions at the subcellular levels. The advantages of nano-based vaccines are the ability to protect a cargo such as RNA, DNA, protein, or synthesis substance and have enhanced stability in a broad range of pH, ambient temperatures, and humidity for long-term storage. Moreover, nano-based vaccines can be engineered to overcome biological barriers such as nonspecific distribution in order to elicit functions in antigen presenting cells. In this review, we will summarize on the developing COVID-19 vaccine strategies and how the nanotechnology can enhance antigen presentation and strong immunogenicity using advanced technology in nanocarrier to deliver antigens. The discussion about their safe, effective, and affordable vaccines to immunize against COVID-19 will be highlighted.

Utilization of metal or non-metal-based functional materials as efficient composites in cancer therapies

There has been great progress in cancer treatment through traditional approaches, even though some of them are still trapped in relative complications such as certain side effects and prospective chances of full recovery. As a conventional method, the immunotherapy approach is regarded as an effective approach to cure cancer. It is mainly promoted by immune checkpoint blocking and adoptive cell therapy, which can utilize the human immune system to attack tumor cells and make them necrose completely or stop proliferating cancer cells. Currently however, immunotherapy shows limited success due to the limitation of real applicable cases of targeted tumor environments and immune systems. Considering the urgent need to construct suitable strategies towards cancer therapy, metallic materials can be used as delivery systems for immunotherapeutic agents in the human body. Metallic materials exhibit a high degree of specificity, effectiveness, diagnostic ability, imaging ability and therapeutic effects with different biomolecules or polymers, which is an effective option for cancer treatment. In addition, these modified metallic materials contain immune-modulators, which can activate immune cells to regulate tumor microenvironments and enhance anti-cancer immunity. Additionally, they can be used as adjuvants with immunomodulatory activities, or as carriers for molecular transport to specific targets, which results in the loading of specific ligands to facilitate specific uptake. Here, we provide an overview of the different types of metallic materials used as efficient composites in cancer immunotherapy. We elaborate on the advancements using metallic materials with functional agents as effective composites in synergistic cancer treatment. Some nonmetallic functional composites also appear as a common phenomenon. Ascribed to the design of the composites themselves, the materials' surface structural characteristics are introduced as the drug-loading substrate. The physical and chemical properties of the functional materials emphasize that further research is required to fully characterize their mechanism, showing appropriate relevance for material toxicology and biomedical applications.

There has been great progress in cancer treatment through traditional approaches, even though some of them are still trapped in relative complications such as certain side effects and prospective chances of full recovery.

Engineered Hydroxyapatite Nanoadjuvants with Controlled Shape and Aspect Ratios Reveal Their Immunomodulatory Potentials

Hydroxyapatite (HAP) has been formulated as adjuvants in vaccines for human use. However, the optimal properties required for HAP nanoparticles to elicit adjuvanticity and the underlying immunopotentiation mechanisms have not been fully elucidated. Herein, a library of HAP nanorods and nanospheres was synthesized to explore the effect of the particle shape and aspect ratio on the immune responses in vitro and adjuvanticity in vivo. It was demonstrated that long aspect ratio HAP nanorods induced a higher degree of cell membrane depolarization and subsequent uptake, and the internalized particles elicited cathepsin B release and mitochondrial reactive oxygen species generation, which further led to pro-inflammatory responses. Furthermore, the physicochemical property-dependent immunostimulation capacities were correlated with their humoral responses in a murine hepatitis B surface antigen immunization model, with long aspect ratio HAP nanorods inducing higher antigen-specific antibody productions. Importantly, HAP nanorods significantly up-regulated the IFN-γ secretion and CD107α expression on CD8⁺ T cells in immunized mice. Further mechanistic studies demonstrated that HAP nanorods with defined properties exerted immunomodulatory effects by enhanced antigen persistence and immune cell recruitments. Our study provides a rational design strategy for engineered nanomaterial-based vaccine adjuvants.

Role of Ligand Distribution in the Cytoskeleton-Associated Endocytosis of Ellipsoidal Nanoparticles

Nanoparticle (NP)–cell interaction mediated by receptor–ligand bonds is a crucial phenomenon in pathology, cellular immunity, and drug delivery systems, and relies strongly on the shape of NPs and the stiffness of the cell. Given this significance, a fundamental question is raised on how the ligand distribution may affect the membrane wrapping of non-spherical NPs under the influence of cytoskeleton deformation. To address this issue, in this work we use a coupled elasticity–diffusion model to systematically investigate the role of ligand distribution in the cytoskeleton-associated endocytosis of ellipsoidal NPs for different NP shapes, sizes, cytoskeleton stiffness, and the initial receptor densities. In this model, we have taken into account the effects of receptor diffusion, receptor–ligand binding, cytoskeleton and membrane deformations, and changes in the configuration entropy of receptors. By solving this model, we find that the uptake process can be significantly influenced by the ligand distribution. Additionally, there exists an optimal state of such a distribution, which corresponds to the fastest uptake efficiency and depends on the NP aspect ratio and cytoskeleton stiffness. We also find that the optimal distribution usually needs local ligand density to be sufficiently high at the large curvature region. Furthermore, the optimal state of NP entry into cells can tolerate slight changes to the corresponding optimal distribution of the ligands. The tolerance to such a change is enhanced as the average receptor density and NP size increase. These results may provide guidelines to control NP–cell interactions and improve the efficiency of target drug delivery systems.

Innovative vaccine platforms against infectious diseases: Under the scope of the COVID-19 pandemic

While classic vaccines have proved greatly efficacious in eliminating serious infectious diseases, innovative vaccine platforms open a new pathway to overcome dangerous pandemics via the development of safe and effective formulations. Such platforms play a key role either as antigen delivery systems or as immune-stimulators that induce both innate and adaptive immune responses. Liposomes or lipid nanoparticles, virus-like particles, nanoemulsions, polymeric or inorganic nanoparticles, as well as viral vectors, all belong to the nanoscale and are the main categories of innovative vaccines that are currently on the market or in clinical and preclinical phases. In this paper, we review the above formulations used in vaccinology and we discuss their connection with the development of safe and effective prophylactic vaccines against SARS-CoV-2.

Gold nanoparticle-based platforms for vaccine development

Since their discovery, therapeutic or prophylactic vaccines represent a promising option to prevent or cure infections and other pathologies, such as cancer or autoimmune disorders. More recently, among a number of nanomaterials, gold nanoparticles (AuNPs) have emerged as novel tools for vaccine developments, thanks to their inherent ability to tune and upregulate immune response. Moreover, owing to their features, AuNPs can exert optimal actions both as delivery systems and as adjuvants. Notwithstanding the potential huge impact in vaccinology, some challenges remain before AuNPs in vaccine formulations can be translated into the clinic. The current review provides an updated overview of the most recent and effective application of gold nanoparticles as efficient means to develop a new generation of vaccine.

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.

Two step promotion of a hot tumor immune environment by gold decorated iron oxide nanoflowers and light-triggered mild hyperthermia

Nanoparticle-mediated photothermal therapy (PTT) is an emerging modality to treat tumors with both spatial and temporal control provided by light activation. Gold decorated iron oxide nanoflowers (GIONF) are good candidates for PTT due to their biocompatibility, biodegradability and light-to-heat conversion. Profound changes in the tumor immune environment might be early induced by the gold and iron oxide metallic agents in addition to the photothermal effects. This study aims to elucidate the outcome of GIONF on their own, and of GIONF-induced mild hyperthermia in the tumor immune infiltrate in a murine model of triple negative breast cancer. First we explored the effects of 24 h GIONF exposure on bone-marrow derived macrophages (BMDM), revealing significant effects on the BMDM phenotype and secretion, 6 days post-incubation, with important downregulation of several cytokines and MHCII expression, predominantly towards a pro-inflammatory response. Intratumoral administration of GIONF promoted an increase in monocyte recruitment at day 1 post-administration, shifting towards a pro-inflammatory anti-tumor microenvironment with lower Treg population and a 4 fold lower CD4/CD8 ratio compared to the control at day 12. On top of the GIONF effects, mild hyperthermia (43 °C for 15 min), although it does not induce significant changes in tumor growth, resulted in an additional increase of CD8+ T lymphocytes and pro-inflammatory cytokines. The combination of a timely controlled immune response to GIONF and to mild hyperthermia could be used as a remotely triggered adjuvant treatment to immunotherapy approaches at the best favorable time-window.

Modulating Osteoimmune Responses by Mesoporous Silica Nanoparticles

The immune response plays an important role in biomaterial-mediated osteogenesis. Nanomaterials may influence immune responses and thereby alter bone regeneration. Mesoporous silica nanoparticles (MSNs) have received much attention for drug delivery and bone regeneration. Recently, immunomodulatory effects of MSNs on osteogenesis have been reported. In this Review, we summarize the osteoimmunomodulation of MSNs, including the effects of MSN characteristics on immune cells and osteogenesis. Impacts of MSNs on immune cells vary according to nanoparticle properties, including surface topography and charge, particle size, and ion release. MSNs with suitable doses can inhibit inflammation and create an immune microenvironment beneficial for bone regeneration by activating immune cells and stimulating cytokine release. Further work is needed to explore and clarify the underlying mechanisms, including crosstalk between various types of immune cells and how to design MSNs to create a suitable immune environment for osteogenesis.

The Interactions between Nanoparticles and the Innate Immune System from a Nanotechnologist Perspective

The immune system contributes to maintaining the body’s functional integrity through its two main functions: recognizing and destroying foreign external agents (invading microorganisms) and identifying and eliminating senescent cells and damaged or abnormal endogenous entities (such as cellular debris or misfolded/degraded proteins). Accordingly, the immune system can detect molecular and cellular structures with a spatial resolution of a few nm, which allows for detecting molecular patterns expressed in a great variety of pathogens, including viral and bacterial proteins and bacterial nucleic acid sequences. Such patterns are also expressed in abnormal cells. In this context, it is expected that nanostructured materials in the size range of proteins, protein aggregates, and viruses with different molecular coatings can engage in a sophisticated interaction with the immune system. Nanoparticles can be recognized or passed undetected by the immune system. Once detected, they can be tolerated or induce defensive (inflammatory) or anti-inflammatory responses. This paper describes the different modes of interaction between nanoparticles, especially inorganic nanoparticles, and the immune system, especially the innate immune system. This perspective should help to propose a set of selection rules for nanosafety-by-design and medical nanoparticle design.

ncRNAs in Therapeutics: Challenges and Limitations in Nucleic Acid-Based Drug Delivery

Non-coding RNAs (ncRNAs) are emerging therapeutic tools but there are barriers to their translation to clinical practice. Key issues concern the specificity of the targets, the delivery of the molecules, and their stability, while avoiding “on-target” and “off-target” side effects. In this “ncRNA in therapeutics” issue, we collect several studies of the differential expression of ncRNAs in cardiovascular diseases, bone metabolism-related disorders, neurology, and oncology, and their potential to be used as biomarkers or therapeutic targets. Moreover, we review recent advances in the use of antisense ncRNAs in targeted therapies with a particular emphasis on their basic biological mechanisms, their translational potential, and future trends.

Precisely Shaped Self-Adjuvanting Peptide Vaccines with Enhanced Immune Responses for HPV-Associated Cancer Therapy

Peptide vaccines exhibit great potential in cancer therapy via eliciting antigen-specific host immune response and long-term immune memory to defend cancer cells. However, the low induced immune response of many developing vaccines implies the imperatives for understanding the favorable structural features of efficient cancer vaccines. Herein, we report on the two groups of self-adjuvanting peptide vaccines with distinct morphology and investigate the relationship between the morphology of peptide vaccines and the induced immune response. Two nanofibril peptide vaccines were created via co-assembly of a pentapeptide with a central 4-aminoproline residue, with its derivative functionalized with antigen epitopes derived from human papillomavirus E7 proteins, whereas utilization of a pentapeptide with a natural proline residue led to the formation of two nanoparticle peptide vaccines. The immunological results of dendritic cell (DCs) maturation and antigen presentation induced by the peptide assemblies implied the self-adjuvanting property of the resulting peptide vaccines. In particular, cellular uptake studies revealed the enhanced internalization and elongated retention of the nanofibril peptide vaccines in DCs, leading to their advanced performance in DC maturation, accumulation at lymph nodes, infiltration of cytotoxic T lymphocytes into tumor tissues, and eventually lysis of in vivo tumor cells, compared to the nanoparticle counterparts. The antitumor immune response caused by the nanofibril peptide vaccines was further augmented when simultaneously administrated with anti-PD-1 checkpoint blockades, suggesting the opportunity of the combinatorial immunotherapy by utilizing the nanofibril peptide vaccines. Our findings strongly demonstrate a robust relationship between the immune response of peptide vaccines and their morphology, thereby elucidating the critical role of morphological control in the design of efficient peptide vaccines and providing the guidance for the design of efficient peptide vaccines in the future.

A nano perspective behind the COVID-19 pandemic

The global pandemic scenario has definitely pushed the scientific community to develop COVID-19 vaccines at unprecedented speed. Nevertheless, a worldwide vaccination campaign is still far from being achieved, making the usual precautionary measures as necessary as at the beginning of the outbreak. Many aspects of the SARS-CoV-2 infectious potential and disease severity do not solely rely on interactions at the molecular level but also on physical-chemical parameters that often involve nanoscale effects. Here the SARS-CoV-2 journey to infect a susceptible host is reviewed, focusing on the nanoscale aspects that play a role in the viral infectivity and disease progression. These nanoscale-driven interactions are essential to establish mitigation-related strategies.

Recent advances in lipopolysaccharide-based glycoconjugate vaccines

INTRODUCTION

The public health burden caused by pathogenic Gram-negative bacteria is increasingly prominent due to antimicrobial resistance. The surface carbohydrates are potential antigens for vaccines against Gram-negative bacteria. The enhanced immunogenicity of the O-specific polysaccharide (O-SP) moiety of LPS when coupled to a carrier protein may protect against bacterial pathogens. However, because of the toxic lipid A moiety and relatively high costs of O-SP isolation, LPS has not been a popular vaccine antigen until recently.

AREAS COVERED

In this review, we discuss the rationales for developing LPS-based glycoconjugate vaccines, principles of glycoconjugate-induced immunity, and highlight the recent developments and challenges faced by LPS-based glycoconjugate vaccines.

EXPERT OPINION

Advances in LPS harvesting, LPS chemical synthesis, and newer carrier proteins in the past decade have propelled LPS-based glycoconjugate vaccines toward further development, through to clinical evaluation. The development of LPS-based glycoconjugates offers a new horizon for vaccine prevention of Gram-negative bacterial infection.

Functionalized Nanoparticles Targeting Tumor-Associated Macrophages as Cancer Therapy

The tumor microenvironment (TME) plays a central role in regulating antitumor immune responses. As an important part of the TME, alternatively activated type 2 (M2) macrophages drive the development of primary and secondary tumors by promoting tumor cell proliferation, tumor angiogenesis, extracellular matrix remodeling and overall immunosuppression. Immunotherapy approaches targeting tumor-associated macrophages (TAMs) in order to reduce the immunosuppressive state in the TME have received great attention. Although these methods hold great potential for the treatment of several cancers, they also face some limitations, such as the fast degradation rate of drugs and drug-induced cytotoxicity of organs and tissues. Nanomedicine formulations that prevent TAM signaling and recruitment to the TME or deplete M2 TAMs to reduce tumor growth and metastasis represent encouraging novel strategies in cancer therapy. They allow the specific delivery of antitumor drugs to the tumor area, thereby reducing side effects associated with systemic application. In this review, we give an overview of TAM biology and the current state of nanomedicines that target M2 macrophages in the course of cancer immunotherapy, with a specific focus on nanoparticles (NPs). We summarize how different types of NPs target M2 TAMs, and how the physicochemical properties of NPs (size, shape, charge and targeting ligands) influence NP uptake by TAMs in vitro and in vivo in the TME. Furthermore, we provide a comparative analysis of passive and active NP-based TAM-targeting strategies and discuss their therapeutic potential.

Safety Evaluation of Nanotechnology Products

Nanomaterials are now being used in a wide variety of biomedical applications. Medical and health-related issues, however, have raised major concerns, in view of the potential risks of these materials against tissue, cells, and/or organs and these are still poorly understood. These particles are able to interact with the body in countless ways, and they can cause unexpected and hazardous toxicities, especially at cellular levels. Therefore, undertaking in vitro and in vivo experiments is vital to establish their toxicity with natural tissues. In this review, we discuss the underlying mechanisms of nanotoxicity and provide an overview on in vitro characterizations and cytotoxicity assays, as well as in vivo studies that emphasize blood circulation and the in vivo fate of nanomaterials. Our focus is on understanding the role that the physicochemical properties of nanomaterials play in determining their toxicity.

Association of a vaccine adjuvant with endogenous HDL increases lymph uptake and dendritic cell activation

Vaccines are a powerful health intervention but there is still an unmet need for effective preventative and therapeutic vaccines for many diseases such as cancer and infections. Interstitial (e.g. subcutaneous (SC)) injection in nano-sized carriers such as high density lipoproteins (HDLs) can improve the access of vaccine subunit antigens or adjuvants to target immune cells in the lymphatics and potentiate vaccination responses such as cytotoxic T lymphocyte (CTL) responses[1-3]. Here we examined how cholesterol conjugation to the vaccine adjuvant CpG, and incorporation into HDL, changes lymphatic absorption and association with, and processing by, dendritic cells (DCs), ultimately influencing adjuvant efficacy. We investigated the lymphatic disposition of cholesterol conjugated CpG incorporated into HDL (HDL(Chol-CpG-Cy5)) relative to cholesterol conjugated (Chol-CpG-Cy5) and unconjugated CpG (free CpG-Cy5) alone after SC administration into rats and mice. HDL (Chol-CpG-Cy5) and Chol-CpG-Cy5 differentially altered CpG absorption into lymph vs. blood, but surprisingly resulted in similarly higher LN accumulation relative to free CpG. The mechanism of access of Chol-CpG-Cy5 into lymph might be partly due to association with endogenous HDL at the injection site followed by transport into lymph in association with the HDL. To measure CpG association with and processing by DCs and the strength of the immune response, mice were vaccinated with free ovalbumin (OVA) co-administered with the different CpG constructs. There were significant changes in DC activation that were reflective of the trend in LN accumulation at 24h post-vaccination. However, T cell response at 24h and 7 days post-vaccination were not significantly different across the CpG groups although the response was less variable for Chol-CpG-Cy5 compared to free CpG Cy5 and also HDL(Chol-CpG-Cy5) - despite similar LN accumulation with the latter. Overall, our data indicate that cholesterol conjugation and incorporation into HDL increases adjuvant lymph disposition and DC activation.

Role of different types of nanomaterials against diagnosis, prevention and therapy of COVID-19

In 2019, a novel type of coronavirus emerged in China called SARS-COV-2, known COVID-19, threatens global health and possesses negative impact on people's quality of life, leading to an urgent need for its diagnosis and remedy. On the other hand, the presence of hazardous infectious waste led to the increase of the risk of transmitting the virus by individuals and by hospitals during the COVID-19 pandemic. Hence, in this review, we survey previous researches on nanomaterials that can be effective for guiding strategies to deal with the current COVID-19 pandemic and also decrease the hazardous infectious waste in the environment. We highlight the contribution of nanomaterials that possess potential to therapy, prevention, detect targeted virus proteins and also can be useful for large population screening, for the development of environmental sensors and filters. Besides, we investigate the possibilities of employing the nanomaterials in antiviral research and treatment development, examining the role of nanomaterials in antiviral- drug design, including the importance of nanomaterials in drug delivery and vaccination, and for the production of medical equipment. Nanomaterials-based technologies not only contribute to the ongoing SARS- CoV-2 research efforts but can also provide platforms and tools for the understanding, protection, detection and treatment of future viral diseases.

Nanotechnology-empowered vaccine delivery for enhancing CD8+ T cells-mediated cellular immunity

After centuries of development, using vaccination to stimulate immunity has become an effective method for prevention and treatment of a variety of diseases including infective diseases and cancers. However, the tailor-made efficient delivery system for specific antigens is still urgently needed due to the low immunogenicity and stability of antigens, especially for vaccines to induce CD8⁺ T cells-mediated cellular immunity. Unlike B cells-mediated humoral immunity, CD8⁺ T cells-mediated cellular immunity mainly aims at the intracellular antigens from microorganism in virus-infected cells or genetic mutations in tumor cells. Therefore, the vaccines for stimulating CD8⁺ T cells-mediated cellular immunity should deliver the antigens efficiently into the cytoplasm of antigen presenting cells (APCs) to form major histocompatibility complex I (MHCI)-antigen complex through cross-presentation, followed by activating CD8⁺ T cells for immune protection and clearance. Importantly, nanotechnology has been emerged as a powerful tool to facilitate these multiple processes specifically, allowing not only enhanced antigen immunogenicity and stability but also APCs-targeted delivery and elevated cross-presentation. This review summarizes the process of CD8⁺ T cells-mediated cellular immunity induced by vaccines and the technical advantages of nanotechnology implementation in general, then provides an overview of the whole spectrum of nanocarriers studied so far and the recent development of delivery nanotechnology in vaccines against infectious diseases and cancer. Finally, we look forward to the future development of nanotechnology for the next generation of vaccines to induce CD8⁺ T cells-mediated cellular immunity.

Gold nanorods enhance different immune cells and allow for efficient targeting of CD4+ Foxp3+ Tregulatory cells

Gold nanoparticles (AuNPs) hold great promise in nanomedicine, yet their successful clinical translation has not been realized. Some challenges include effective AuNP targeting and delivery to improve modulation of immune cells of interest while limiting potential adverse effects. In order to overcome these challenges, we must fully understand how AuNPs impact different immune cell subsets, particularly within the dendritic cell and T cell compartments. Herein, we show that polyethylene glycol coated (PEG) gold nanorods (AuNRs) and PEG AuNRs covered with a thin layer of silver (AuNR/Ag) may enhance the immune response towards immune suppression or activation. We also studied the ability to enhance CD4+ Foxp3+ Tregs in vitro using AuNRs functionalized with interleukin 2 (IL2), a cytokine that is important in Treg development and homeostasis. Our results indicate that AuNRs enhance different immune cells and that NP composition matters in immune targeting. This knowledge will help us understand how to better design AuNRs to target and enhance the immune system.

Nanotechnology against COVID-19: Immunization, diagnostic and therapeutic studies

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in early 2020 soon led to the global pandemic of Coronavirus Disease 2019 (COVID-19). Since then, the clinical and scientific communities have been closely collaborating to develop effective strategies for controlling the ongoing pandemic. The game-changing fields of recent years, nanotechnology and nanomedicine have the potential to not only design new approaches, but also to improve existing methods for the fight against COVID-19. Nanomaterials can be used in the development of highly efficient, reusable personal protective equipment, and antiviral nano-coatings in public settings could prevent the spread of SARS-CoV-2. Smart nanocarriers have accelerated the design of several therapeutic, prophylactic, or immune-mediated approaches against COVID-19. Some nanovaccines have even entered Phase IΙ/IIΙ clinical trials. Several rapid and cost-effective COVID-19 diagnostic techniques have also been devised based on nanobiosensors, lab-on-a-chip systems, or nanopore technology. Here, we provide an overview of the emerging role of nanotechnology in the prevention, diagnosis, and treatment of COVID-19.

Nanoparticles for generating antigen-specific T cells for immunotherapy

T cell therapy shows promise as an immunotherapy in both immunostimulatory and immunosuppressive applications. However, the forms of T cell-based therapy that are currently in the clinic, such as adoptive cell transfer and vaccines, are limited by cost, time-to-treatment, and patient variability. Nanoparticles offer a modular, universal platform to improve the efficacy of various T cell therapies as nanoparticle properties can be easily modified for enhanced cell targeting, organ targeting, and cell internalization. Nanoparticles can enhance or even replace endogenous cells during each step of generating an antigen-specific T cell response - from antigen presentation and T cell activation to T cell maintenance. In this review, we discuss the unique applications of nanoparticles for antigen-specific T cell therapy, focusing on nanoparticles as vaccines (to activate endogenous antigen presenting cells (APCs)), as artificial Antigen Presenting Cells (aAPCs, to directly activate T cells), and as drug delivery vehicles (to support activated T cells).

A self-assembling nanoparticle: Implications for the development of thermostable vaccine candidates

Effective controls on viral infections rely on the continuous development in vaccine technology. Nanoparticle (NP) antigens are highly immunogenic based on their unique physicochemical properties, making them molecular scaffolds to present soluble vaccine antigens. Here, viral targets (113-354 aas) were genetically fused to N terminal of mi3, a protein that self-assembles into nanoparticles composed of 60 subunits. With transmission electron microscopy, it was confirmed that target-mi3 fusion proteins which have insertions of up to 354 aas in N terminal form intact NPs. Moreover, viral targets are surface-displayed on NPs as indicated in dynamic light scattering. NPs exhibit perfect stability after long-term storage at room temperature. Moreover, SP-E2-mi3 NPs enhance antigen uptake and maturation in dendritic cells (DCs) via up-regulating marker molecules and immunostimulatory cytokines. Importantly, in a mouse model, SP-E2-mi3 nanovaccines against Classical swine fever virus (CSFV) remarkably improved CSFV-specific neutralizing antibodies (NAbs) and cellular immunity related cytokines (IFN-γ and IL-4) as compared to monomeric E2. Specially, improved NAb response with more than tenfold increase in NAb titer against both CSFV Shimen and HZ-08 strains indicated better cross-protection against different genotypes. Collectively, this structure-based, self-assembling NP provides an attractive platform to improve the potency of subunit vaccine for emerging pathogens.

Green synthesis of gold nanoparticles for immune response regulation: Mechanisms, applications, and perspectives

Immune responses are involved in the pathogenesis of many diseases, including cancer, autoimmune diseases, and chronic inflammation. These responses are attributed to immune cells that produce cytokines, mediate cytotoxicity, and synthesize antibodies. Gold nanoparticles (GNPs) are novel agents that intervene with immune responses because of their unique physical-chemical properties. In particular, GNPs enhance anti-tumour activity during immunotherapy and eliminate excessive inflammation in autoimmune diseases. However, GNPs synthesized by conventional methods are toxic to living organisms. Green biosynthesis provides a safe and eco-friendly method to obtain GNPs from microbes or plant extracts. In this review, we describe several patterns for green GNP biosynthesis. The applications of GNPs to target immune cells and modulate the immune response are summarized. In particular, we elaborate on how GNPs regulate innate immunity and adaptive immunity, including inflammatory signaling and immune cell differentiation. Finally, perspectives and challenges in utilizing green biosynthesized GNPs for novel therapeutic approaches are discussed.

Targeting immunosuppressor cells with nanoparticles in autoimmunity: How far have we come to?

Autoimmunity is the assault of immune response towards self-antigens, resulting to inflammation and tissue injury. It is staged into three phases and caused by malfunction of immune tolerance. In our body, immune tolerance is synchronized by several immunosuppressor cells such as regulatory T cells and B cells as well as myeloid-derived suppressor cells, which are prominently dysregulated in autoimmunity. Hence, targeting these cell populations serve as a significant potential in the therapy of autoimmunity. Nanotechnology with its advantageous properties is shown to be a remarkable tool as drug delivery system in this field. This review focused on the development of therapeutics in autoimmune diseases utilizing various nanoparticles formulation based on two targeting approaches in autoimmunity, passive and active targeting. Lastly, this review outlined the approved present nanomedicines as well as in clinical evaluations and issues regarding the lack of translation of these nanomedicines into the market, despite the abundant of positive experimental observations.

Polymer-Functionalized Upconversion Nanoparticles for Light/Imaging-Guided Drug Delivery

The strong upconversion luminescence (UCL) of upconversion nanoparticles (UCNPs) endows the nanoparticles with attractive features for combined imaging and drug delivery. UCNPs convert near-infrared (NIR) light into light of shorter wavelengths such as light in the ultraviolet (UV) and visible regions, which can be used for light-guided drug delivery. Although light-responsive drug delivery systems as such have been known for many years, their application in medicine is limited, as strong UV-light can be damaging to tissue; moreover, UV light will not penetrate deeply into the skin, an issue that UCNPs can now address. However, UCNPs, as obtained after synthesis, are usually hydrophobic and require further surface functionalization to be stable in plasma. Polymers can serve as versatile surface coatings, as they can provide good colloidal stability, prevent the formation of a protein corona, provide a matrix for drugs, and be stimuli-responsive. In this Review, we provide a brief overview of the most recent progress in the synthesis of UCNPs with different shapes/sizes. We will then discuss the purpose of polymer coating for drug delivery before summarizing the strategies to coat UCNPs with various polymers. We will introduce the different polymers that have so far been used to coat UCNPs with the purpose to create a drug delivery system, focusing in detail on light-responsive polymers. To expand the application of UCNPs to allow photothermal therapy or magnetic resonance imaging (MRI) or to simply enhance the loading capacity of drugs, UCNPs were often combined with other materials to generate multifunctional nanoparticles such as carbon-based NPs and nanoMOFs. We then conclude with a discussion on drug loading and release and summarize the current knowledge on the toxicity of these polymer-coated UCNPs.

Double-edged sword: Therapeutic efficacy versus toxicity evaluations of doped titanium implants

Titanium-based orthopaedic/dental implants modified with various metal-doping strategies can enhance local therapy and bioactivity. Intentional or unintentional (because of loading and wear) release of metal ions/nanoparticles (NPs) from metal-doped implants can be therapeutic or cause adverse local tissue reactions, compromising long-term survival. Strategies to incorporate metals into implants, such as superficial or deep loading inside nano-engineered surfaces, including nanotubes, and the physiochemical characteristics of the released species significantly influence both their therapeutic and cytotoxic potential. In this review, we compare and contrast this 'double-edged sword' to arrive at an improved understanding of metal-doped implants to enable controlled therapy while minimising cytotoxicity concerns.

Impact of lipid nanoparticle size on mRNA vaccine immunogenicity

Lipid nanoparticles (LNP) are effective delivery vehicles for messenger RNA (mRNA) and have shown promise for vaccine applications. Yet there are no published reports detailing how LNP biophysical properties can impact vaccine performance. In our hands, a retrospective analysis of mRNA LNP vaccine in vivo studies revealed a relationship between LNP particle size and immunogenicity in mice using LNPs of various compositions. To further investigate this, we designed a series of studies to systematically change LNP particle size without altering lipid composition and evaluated biophysical properties and immunogenicity of the resulting LNPs. While small diameter LNPs were substantially less immunogenic in mice, all particle sizes tested yielded a robust immune response in non-human primates (NHP).

Recent advances in regenerative medicine strategies for cancer treatment

Cancer stands as one of the most leading causes of death worldwide, while one of the most significant challenges in treating it is revealing novel alternatives to predict, diagnose, and eradicate tumor cell growth. Although various methods, such as surgery, chemotherapy, and radiation therapy, are used today to treat cancer, its mortality rate is still high due to the numerous shortcomings of each approach. Regenerative medicine field, including tissue engineering, cell therapy, gene therapy, participate in cancer treatment and development of cancer models to improve the understanding of cancer biology. The final intention is to convey fundamental and laboratory research to effective clinical treatments, from the bench to the bedside. Proper interpretation of research attempts helps to lessen the burden of treatment and illness for patients. The purpose of this review is to investigate the role of regenerative medicine in accelerating and improving cancer treatment. This study examines the capabilities of regenerative medicine in providing novel cancer treatments and the effectiveness of these treatments to clarify this path as much as possible and promote advanced future research in this field.

Nanovaccine-Based Strategies to Overcome Challenges in the Whole Vaccination Cascade for Tumor Immunotherapy

Nanovaccine-based immunotherapy (NBI) has received greater attention recently for its potential to prime tumor-specific immunity and establish a long-term immune memory that prevents tumor recurrence. Despite encouraging results in the recent studies, there are still numerous challenges to be tackled for eliciting potent antitumor immunity using NBI strategies. Based on the principles that govern immune response, here it is proposed that these challenges need to be addressed at the five critical cascading events: Loading tumor-specific antigens by nanoscale drug delivery systems (L); Draining tumor antigens to lymph nodes (D); Internalization by dendritic cells (DCs) (I); Maturation of DCs by costimulatory signaling (M); and Presenting tumor-peptide-major histocompatibility complexes to T cells (P) (LDIMP cascade in short). This review provides a detailed and objective overview of emerging NBI strategies to improve the efficacy of nanovaccines in each step of the LDIMP cascade. It is concluded that the balance between each step must be optimized by delicate designing and modification of nanovaccines and by combining with complementary approaches to provide a synergistic immunity in the fight against cancer.

Development of Effective Tumor Vaccine Strategies Based on Immune Response Cascade Reactions

To solve the problems of high toxicity and poor efficacy of existing tumor treatment methods, researchers have developed a variety of tumor immunotherapies. Among them, tumor vaccines activate antigen-presenting cells and T lymphocytes upstream of the cancer-immunity cycle are considered the most promising therapy to activate the immune system. Nanocarriers are considered the most promising tumor vaccine delivery vehicles, including polymer nanocarriers, lipid nanocarriers, inorganic nanocarriers, and biomimetic nanocarriers that have been developed for vaccine delivery. Based on the cascade reaction for tumor vaccines to exert their effects, this review summarizes the four key factors for the design and construction of nano-tumor vaccines. The composition and functional characteristics of the corresponding preferred nanocarriers are illustrated to provide a reference for the development of effective tumor vaccines. Finally, potential challenges and perspectives are illustrated in the hope of improving the efficacy of tumor vaccine immunotherapy and accelerating the clinical transformation of next-generation tumor vaccines.

Multicomponent Gold-Linked Glycoconjugate Vaccine Elicits Antigen-Specific Humoral and Mixed TH1-TH17 Immunity, Correlated with Increased Protection against Burkholderia pseudomallei

Burkholderia pseudomallei is the causative agent of melioidosis, a fatal disease with a high mortality rate. The intrinsic resistance to commonly used antibiotics combined with the complex bacterial life cycle has hampered the development of preventive and therapeutic interventions and vaccines. Furthermore, the need of humoral and cell-mediated immunity in protection against B. pseudomallei has complicated the development of effective vaccines. Antigen delivery vaccine platforms that promote humoral and cellular responses while maintaining a safe profile are a roadblock to developing subunit vaccines against intracellular pathogens. Gold nanoparticles (AuNPs) were used for the delivery of multicomponent antigens with the goal of inducing vaccine-mediated immunity, promoting protection against melioidosis disease. Different nanoglycoconjugates using predicted immunogenic protein candidates, Hcp1, FlgL, OpcP, OpcP1, OmpW, and hemagglutinin, were covalently coupled to AuNPs, together with the lipopolysaccharide (LPS) from Burkholderia thailandensis, which acted as an additional antigen. Animals immunized with individually coupled (AuNP-protein-LPS) formulations containing OpcP or OpcP1, together with CpG as an adjuvant, showed a significant increase in protection, whereas a nanovaccine combination (AuNP-Combo2-LPS) showed significant and complete protection against a lethal intranasal B. pseudomallei challenge. Animals immunized with AuNP-Combo2-LPS showed robust humoral antigen-specific (IgG and IgA) responses with higher IgG2c titer, indicating a T_H1-skewed response and promotion of macrophage uptake. In addition, immunization with the nanovaccine combination resulted in a mixed antigen-specific T_H1-T_H17 cytokine profile after immunization. This study provides the basis for an elegant and refined multicomponent glycoconjugate vaccine formulation capable of eliciting both humoral and cell-mediated responses against lethal B. pseudomallei challenge.