Rapid and Persistent Delivery of Antigen by Lymph Node Targeting PRINT Nanoparticle Vaccine Carrier To Promote Humoral Immunity

Administration sequence- and formation-dependent vaccination using acid-degradable polymeric nanoparticles with high antigen encapsulation capability

Vaccines aim to efficiently and specifically activate the immune system via a cascade of antigen uptake, processing, and presentation by antigen-presenting cells (APCs) to CD4 and CD8 T cells, which in turn drive humoral and cellular immune responses. The specific formulation of vaccine carriers can not only shield the antigens from premature sequestering before reaching APCs but also favorably promote intracellular antigen presentation and processing. This study compares two different acid-degradable polymeric nanoparticles that are capable of encapsulating a moderately immunogenic antigen, GFP, at nearly full efficacy via electrostatic interactions or molecular affinity between His tag and Ni-NTA-conjugated monomners. This resulted in GFP-encapsulating NPs composed of ketal monomers and crosslinkers (KMX/GFP NPs) and NTA-conjugated ketal monomers and crosslinkers (NKMX/GFP NPs), respectively. Encapsulated GFP was found to be released more rapidly from NKMX/GFP NPs (electrostatic encapsulation) than from KMX/GFP NPs (affinity-driven encapsulation). In vivo vaccination studies demonstrated that while repeated injections of either NP formulation resulted in poorer generation of anti-GFP antibodies than injections of the GFP antigen itself, sequential injections of NPs and GFP as prime and booster vaccines, respectively, restored the humoral response. We proposed that NPs primarily assist APCs in antigen presentation by T cells, and B cells need to be further stimulated by free protein antigens to produce antibodies. The findings of this study suggest that the immune response can be modulated by varying the chemistry of vaccine carriers and the sequences of vaccination with free antigens and antigen-encapsulating NPs.

Biomaterial engineering strategies for B cell immunity modulations

B cell immunity has a penetrating effect on human health and diseases. Therapeutics aiming to modulate B cell immunity have achieved remarkable success in combating infections, autoimmunity, and malignancies. However, current treatments still face significant limitations in generating effective long-lasting therapeutic B cell responses for many conditions. As the understanding of B cell biology has deepened in recent years, clearer regulation networks for B cell differentiation and antibody production have emerged, presenting opportunities to overcome current difficulties and realize the full therapeutic potential of B cell immunity. Biomaterial platforms have been developed to leverage these emerging concepts to augment therapeutic humoral immunity by facilitating immunogenic reagent trafficking, regulating T cell responses, and modulating the immune microenvironment. Moreover, biomaterial engineering tools have also advanced our understanding of B cell biology, further expediting the development of novel therapeutics. In this review, we will introduce the general concept of B cell immunobiology and highlight key biomaterial engineering strategies in the areas including B cell targeted antigen delivery, sustained B cell antigen delivery, antigen engineering, T cell help optimization, and B cell suppression. We will also discuss our perspective on future biomaterial engineering opportunities to leverage humoral immunity for therapeutics.

Lymphatic distribution considerations for subunit vaccine design and development

Subunit vaccines are an important platform for controlling current and emerging infectious diseases. The lymph nodes are the primary site generating the humoral response and delivery of antigens to these sites is critical to effective immunization. Indeed, the duration of antigen exposure within the lymph node is correlated with the antibody response. While current licensed vaccines are typically given through the intramuscular route, injecting vaccines subcutaneously allows for direct access to lymphatic vessels and therefore can enhance the transfer of antigen to the lymph nodes. However, protein subunit antigen uptake into the lymph nodes is inefficient, and subunit vaccines require adjuvants to stimulate the initial immune response. Therefore, formulation strategies have been developed to enhance the exposure of subunit proteins and adjuvants to the lymph nodes by increasing lymphatic uptake or prolonging the retention at the injection site. Given that lymph node exposure is a crucial consideration in vaccine design, in depth analyses of the pharmacokinetics of antigens and adjuvants should be the focus of future preclinical and clinical studies. This review will provide an overview of formulation strategies for targeting the lymphatics and prolonging antigen exposure and will discuss pharmacokinetic evaluations which can be applied toward vaccine development.

Design and Evaluation of Synthetic Delivery Formulations for Peptide-Based Cancer Vaccines

With the recent advances in neoantigen identification, peptide-based cancer vaccines offer substantial potential in the field of immunotherapy. However, rapid clearance, low immunogenicity, and insufficient antigen-presenting cell (APC) uptake limit the efficacy of peptide-based cancer vaccines. This review explores the barriers hindering vaccine efficiency, highlights recent advancements in synthetic delivery systems, and features strategies for the key delivery steps of lymph node (LN) drainage, APC delivery, cross-presentation strategies, and adjuvant incorporation. This paper also discusses the design of preclinical studies evaluating vaccine efficiency, including vaccine administration routes and murine tumor models.

Therapeutic synthetic and natural materials for immunoengineering

Immunoengineering is a rapidly evolving field that has been driving innovations in manipulating immune system for new treatment tools and methods. The need for materials for immunoengineering applications has gained significant attention in recent years due to the growing demand for effective therapies that can target and regulate the immune system. Biologics and biomaterials are emerging as promising tools for controlling immune responses, and a wide variety of materials, including proteins, polymers, nanoparticles, and hydrogels, are being developed for this purpose. In this review article, we explore the different types of materials used in immunoengineering applications, their properties and design principles, and highlight the latest therapeutic materials advancements. Recent works in adjuvants, vaccines, immune tolerance, immunotherapy, and tissue models for immunoengineering studies are discussed.

Detachable-dissolvable-microneedle as a potent subunit vaccine delivery device that requires no cold-chain

Although vaccine administration by microneedles has been demonstrated, delivery reliability issues have prevented their implementation. Through an ex vivo porcine skin experiment, we show visual evidence indicating that detachable dissolvable microneedles (DDMN) can deposit cargo into the dermis with insignificant loss of cargo to the stratum corneum. Using ovalbumin (OVA), a model antigen vaccine, as a cargo, the ex vivo experiments yielded a delivery efficiency of 86.08 ± 4.16 %. At room temperature, OVA could be stabilized for up to 35 days in DDMN made from hyaluronic acid and trehalose. The DDMN matrix could improve the denaturation temperature of the OVA from around 70-120 °C to over 150 °C, as demonstrated by differential scanning calorimetric analysis. In vivo delivery of OVA antigen into the mice's skin via DDMN elicited 10 times higher specific antibody responses compared to conventional intramuscular injection. We envision DDMN as an effective, precise dosing, intradermal vaccine delivery system that may require no cold-chain, offers a dose-sparing effect, and can be administered easily.

Research progress of nanovaccine in anti-tumor immunotherapy

Tumor vaccines aim to activate dormant or unresponsive tumor-specific T lymphocytes by using tumor-specific or tumor-associated antigens, thus enhancing the body's natural defense against cancer. However, the effectiveness of tumor vaccines is limited by the presence of tumor heterogeneity, low immunogenicity, and immune evasion mechanisms. Fortunately, multifunctional nanoparticles offer a unique chance to address these issues. With the advantages of their small size, high stability, efficient drug delivery, and controlled surface chemistry, nanomaterials can precisely target tumor sites, improve the delivery of tumor antigens and immune adjuvants, reshape the immunosuppressive tumor microenvironment, and enhance the body's anti-tumor immune response, resulting in improved efficacy and reduced side effects. Nanovaccine, a type of vaccine that uses nanotechnology to deliver antigens and adjuvants to immune cells, has emerged as a promising strategy for cancer immunotherapy due to its ability to stimulate immune responses and induce tumor-specific immunity. In this review, we discussed the compositions and types of nanovaccine, and the mechanisms behind their anti-tumor effects based on the latest research. We hope that this will provide a more scientific basis for designing tumor vaccines and enhancing the effectiveness of tumor immunotherapy.

Targeting lymph node delivery with nanovaccines for cancer immunotherapy: recent advances and future directions

Although cancer immunotherapy is a compelling approach against cancer, its effectiveness is hindered by the challenge of generating a robust and durable immune response against metastatic cancer cells. Nanovaccines, specifically engineered to transport cancer antigens and immune-stimulating agents to the lymph nodes, hold promise in overcoming these limitations and eliciting a potent and sustained immune response against metastatic cancer cells. This manuscript provides an in-depth exploration of the lymphatic system's background, emphasizing its role in immune surveillance and tumor metastasis. Furthermore, it delves into the design principles of nanovaccines and their unique capability to target lymph node metastasis. The primary objective of this review is to provide a comprehensive overview of the current advancements in nanovaccine design for targeting lymph node metastasis, while also discussing their potential to enhance cancer immunotherapy. By summarizing the state-of-the-art in nanovaccine development, this review aims to shed light on the promising prospects of harnessing nanotechnology to potentiate cancer immunotherapy and ultimately improve patient outcomes.

A Retrospective Analysis of Preclinical and Clinical Pharmacokinetics from Administration of Long-Acting Aqueous Suspensions

Administration of long-acting injectable suspensions is an increasingly common approach to increasing patient compliance and improving therapeutic efficacy through less frequent dosing. While several long-acting suspensions have recently been marketed, parameters modulating drug absorption from suspension-based formulations are not well understood. Further, methods for predicting clinical pharmacokinetic data from preclinical studies are not well established. Together, these limitations hamper compound selection, formulation design and formulation selection through heavy reliance on iterative optimization in preclinical and clinical studies. This article identifies key parameters influencing absorption from suspension-based formulations through compilation and analysis of preclinical and clinical pharmacokinetic data of seven compounds marketed as suspensions; achievable margins for predicting the clinical dose and input rate from preclinical studies as a function of the preclinical species, the clinical injection location and the intended therapeutic duration were also established.

Application of Nano-Delivery Systems in Lymph Nodes for Tumor Immunotherapy

Immunotherapy has become a promising research "hotspot" in cancer treatment. "Soldier" immune cells are not uniform throughout the body; they accumulate mostly in the immune organs such as the spleen and lymph nodes (LNs), etc. The unique structure of LNs provides the microenvironment suitable for the survival, activation, and proliferation of multiple types of immune cells. LNs play an important role in both the initiation of adaptive immunity and the generation of durable anti-tumor responses. Antigens taken up by antigen-presenting cells in peripheral tissues need to migrate with lymphatic fluid to LNs to activate the lymphocytes therein. Meanwhile, the accumulation and retaining of many immune functional compounds in LNs enhance their efficacy significantly. Therefore, LNs have become a key target for tumor immunotherapy. Unfortunately, the nonspecific distribution of the immune drugs in vivo greatly limits the activation and proliferation of immune cells, which leads to unsatisfactory anti-tumor effects. The efficient nano-delivery system to LNs is an effective strategy to maximize the efficacy of immune drugs. Nano-delivery systems have shown beneficial in improving biodistribution and enhancing accumulation in lymphoid tissues, exhibiting powerful and promising prospects for achieving effective delivery to LNs. Herein, the physiological structure and the delivery barriers of LNs were summarized and the factors affecting LNs accumulation were discussed thoroughly. Moreover, developments in nano-delivery systems were reviewed and the transformation prospects of LNs targeting nanocarriers were summarized and discussed.

Nanovaccines for cancer immunotherapy: Focusing on complex formation between adjuvant and antigen

As an interesting cancer immunotherapy approach, cancer vaccines have been developed to deliver tumor antigens and adjuvants to antigen-presenting cells (APCs). Although the safety and easy production shifted the vaccine designing platforms toward the subunit vaccines, their efficacy is limited due to inefficient vaccine delivery. Nanotechnology-based vaccines, called nanovaccines, address the delivery limitations through co-delivery of antigens and adjuvants into lymphoid organs and APCs and their intracellular release, leading to cross-presentation of antigens and induction of potent anti-tumor immune responses. Although the nanovaccines, either as encapsulating agents or biomimetic nanoparticles, exert the desired anti-tumor activities, there is evidence that the mixing formulation to form nanocomplexes between antigens and adjuvants based on the electrostatic interactions provokes high levels of immune responses owing to Ags' availability and faster release. Here, we summarized the various platforms for developing cancer vaccines and the advantages of using delivery systems. The cancer nanovaccines, including nanoparticle-based and biomimetic-based nanovaccines, are discussed in detail. Finally, we focused on the nanocomplexes formation between antigens and adjuvants as promising cancer nanovaccine platforms.

VelcroVax: a "Bolt-On" Vaccine Platform for Glycoprotein Display

Having varied approaches to the design and manufacture of vaccines is critical in being able to respond to worldwide needs and newly emerging pathogens. Virus-like particles (VLPs) form the basis of two of the most successful licensed vaccines (against hepatitis B virus [HBV] and human papillomavirus). They are produced by recombinant expression of viral structural proteins, which assemble into immunogenic nanoparticles. VLPs can be modified to present unrelated antigens, and here we describe a universal "bolt-on" platform (termed VelcroVax) where the capturing VLP and the target antigen are produced separately. We utilize a modified HBV core (HBcAg) VLP with surface expression of a high-affinity binding sequence (Affimer) directed against a SUMO tag and use this to capture SUMO-tagged gp1 glycoprotein from the arenavirus Junín virus (JUNV). Using this model system, we have solved the first high-resolution structures of VelcroVax VLPs and shown that the VelcroVax-JUNV gp1 complex induces superior humoral immune responses compared to the noncomplexed viral protein. We propose that this system could be modified to present a range of antigens and therefore form the foundation of future rapid-response vaccination strategies. IMPORTANCE The hepatitis B core protein (HBc) forms noninfectious virus-like particles, which can be modified to present a capturing molecule, allowing suitably tagged antigens to be bound on their surface. This system can be adapted and provides the foundation for a universal "bolt-on" vaccine platform (termed VelcroVax) that can be easily and rapidly modified to generate nanoparticle vaccine candidates.

Locoregional Lymphatic Delivery Systems Using Nanoparticles and Hydrogels for Anticancer Immunotherapy

The lymphatic system has gained significant interest as a target tissue to control cancer progress, which highlights its central role in adaptive immune response. Numerous mechanistic studies have revealed the benefits of nano-sized materials in the transport of various cargos to lymph nodes, overcoming barriers associated with lymphatic physiology. The potential of sustained drug delivery systems in improving the therapeutic index of various immune modulating agents is also being actively discussed. Herein, we aim to discuss design rationales and principles of locoregional lymphatic drug delivery systems for invigorating adaptive immune response for efficient antitumor immunotherapy and provide examples of various advanced nanoparticle- and hydrogel-based formulations.

Sustained delivery approaches to improving adaptive immune responses

The immune system is one of the most important, complex biological networks regulating and protecting human health. Its precise modulation can prevent deadly infections and fight cancer. Accordingly, prophylactic vaccines and cancer immunotherapies are some of the most powerful technologies to protect against potential dangers through training of the immune system. Upon immunization, activation and maturation of B and T cells of the adaptive immune system are necessary for development of proper humoral and cellular protection. Yet, the exquisite organization of the immune system requires spatiotemporal control over the exposure of immunomodulatory signals. For example, while the human immune system has evolved to develop immunity to natural pathogenic infections that often last for weeks, current prophylactic vaccination technologies only expose the immune system to immunomodulatory signals for hours to days. It has become clear that leveraging sustained release technologies to prolong immunogen and adjuvant exposure can increase the potency, durability, and quality of adaptive immune responses. Over the past several years, tremendous breakthroughs have been made in the design of novel biomaterials such as nanoparticles, microparticles, hydrogels, and microneedles that can precisely control and the presentation of immunomodulatory signals to the immune system. In this review, we discuss relevant sustained release strategies and their corresponding benefits to cellular and humoral responses.

Immunotherapeutic nanoparticles: From autoimmune disease control to the development of vaccines

The development of nanoparticles (NPs) with potential therapeutic uses represents an area of vast interest in the scientific community during the last years. Recently, the pandemic caused by COVID-19 motivated a race for vaccines creation to overcome the crisis generated. This is a good demonstration that nanotechnology will most likely be the basis of future immunotherapy. Moreover, the number of publications based on nanosystems has significantly increased in recent years and it is expected that most of these developments can go on to experimentation in clinical stages soon. The therapeutic use of NPs to combat different diseases such as cancer, allergies or autoimmune diseases will depend on their characteristics, their targets, and the transported molecules. This review presents an in-depth analysis of recent advances that have been developed in order to obtain novel nanoparticulate based tools for the treatment of allergies, autoimmune diseases and for their use in vaccines. Moreover, it is highlighted that by providing targeted delivery an increase in the potential of vaccines to induce an immune response is expected in the future. Definitively, the here gathered analysis is a good demonstration that nanotechnology will be the basis of future immunotherapy.

Biological Nanoparticles in Vaccine Development

Vaccines represent one of the most successful public health initiatives worldwide. However, despite the vast number of highly effective vaccines, some infectious diseases still do not have vaccines available. New technologies are needed to fully realize the potential of vaccine development for both emerging infectious diseases and diseases for which there are currently no vaccines available. As can be seen by the success of the COVID-19 mRNA vaccines, nanoscale platforms are promising delivery vectors for effective and safe vaccines. Synthetic nanoscale platforms, including liposomes and inorganic nanoparticles and microparticles, have many advantages in the vaccine market, but often require multiple doses and addition of artificial adjuvants, such as aluminum hydroxide. Biologically derived nanoparticles, on the other hand, contain native pathogen-associated molecular patterns (PAMPs), which can reduce the need for artificial adjuvants. Biological nanoparticles can be engineered to have many additional useful properties, including biodegradability, biocompatibility, and are often able to self-assemble, thereby allowing simple scale-up from benchtop to large-scale manufacturing. This review summarizes the state of the art in biologically derived nanoparticles and their capabilities as novel vaccine platforms.

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.

Mannose-binding lectin and complement mediate follicular localization and enhanced immunogenicity of diverse protein nanoparticle immunogens

Nanoparticle (NP) vaccine formulations promote immune responses through multiple mechanisms. We recently reported that mannose-binding lectin (MBL) triggers trafficking of glycosylated HIV Env-immunogen NPs to lymph node follicles. Here, we investigate effects of MBL and complement on NP forms of HIV and other viral antigens. MBL recognition of oligomannose on gp120 nanoparticles significantly increases antigen accumulation in lymph nodes and antigen-specific germinal center (GC) responses. MBL and complement also mediate follicular trafficking and enhance GC responses to influenza, HBV, and HPV particulate antigens. Using model protein nanoparticles bearing titrated levels of glycosylation, we determine that mannose patches at a minimal density of 2.1 × 10^-3 mannose patches/nm² are required to trigger follicular targeting, which increases with increasing glycan density up to at least ∼8.2 × 10^-3 patches/nm². Thus, innate immune recognition of glycans has a significant impact on humoral immunity, and these findings provide a framework for engineering glycan recognition to optimize vaccine efficacy.

Nanotechnology-Based Approaches to Promote Lymph Node Targeted Delivery of Cancer Vaccines

Vaccines are a promising immunotherapy that awakens the human immune system to inhibit and eliminate cancer with fewer side effects compared with traditional radiotherapy and chemotherapy. Although cancer vaccines have shown some efficacy, there are still troublesome bottlenecks to expand their benefits in the clinic, including weak immune effects and limited therapeutic outcomes. In the past few years, in addition to neoantigen screening, a main branch of the efforts has been devoted to promoting the lymph nodes (LNs) targeting of cancer vaccines and the cross-presentation of antigens by dendritic cells (DCs), two cardinal stages in effective initiation of the immune response. Especially, nanomaterials have shown hopeful biomedical applications in the improvement of vaccine effectiveness. This Review briefly outlines the possible mechanisms by which nanoparticle properties affect LN targeting and antigen cross-presentation and then gives an overview of state-of-the-art advances in improving these biological outcomes with nanotechnology.

Designing spatial and temporal control of vaccine responses

Vaccines are the key technology to combat existing and emerging infectious diseases. However, increasing the potency, quality and durability of the vaccine response remains a challenge. As our knowledge of the immune system deepens, it becomes clear that vaccine components must be in the right place at the right time to orchestrate a potent and durable response. Material platforms, such as nanoparticles, hydrogels and microneedles, can be engineered to spatially and temporally control the interactions of vaccine components with immune cells. Materials-based vaccination strategies can augment the immune response by improving innate immune cell activation, creating local inflammatory niches, targeting lymph node delivery and controlling the time frame of vaccine delivery, with the goal of inducing enhanced memory immunity to protect against future infections. In this Review, we highlight the biological mechanisms underlying strong humoral and cell-mediated immune responses and explore materials design strategies to manipulate and control these mechanisms.

Strategy and clinical application of up-regulating cross presentation by DCs in anti-tumor therapy

The cross presentation of exogenous antigen (Ag) by dendritic cells (DCs) facilitates a diversified mode of T-cell activation, orchestrates specific humoral and cellular immunity, and contributes to an efficient anti-tumor immune response. DCs-mediated cross presentation is subject to both intrinsic and extrinsic factors, including the homing and phenotype of DCs, the spatiotemporal trafficking and degradation kinetics of Ag, and multiple microenvironmental clues, with many details largely unexplored. Here, we systemically review the current mechanistic understanding and regulation strategies of cross presentation by heterogeneous DC populations. We also provide insights into the future exploitation of DCs cross presentation for a better clinical efficacy in anti-tumor therapy.

The ancillary effects of nanoparticles and their implications for nanomedicine

Nanoparticles are often engineered as a scaffolding system to combine targeting, imaging and/or therapeutic moieties into a unitary agent. However, mostly overlooked, the nanomaterial itself interacts with biological systems exclusive of application-specific particle functionalization. This nanoparticle biointerface has been found to elicit specific biological effects, which we term 'ancillary effects'. In this Review, we describe the current state of knowledge of nanobiology gleaned from existing studies of ancillary effects with the objectives to describe the potential of nanoparticles to modulate biological effects independently of any engineered function; evaluate how these effects might be relevant for nanomedicine design and functional considerations, particularly how they might be useful to inform clinical decision-making; identify potential clinical harm that arises from adverse nanoparticle interactions with biology; and, finally, highlight the current lack of knowledge in this area as both a barrier and an incentive to the further development of nanomedicine.

Transdermal vaccination via 3D-printed microneedles induces potent humoral and cellular immunity

Vaccination is an essential public health measure for infectious disease prevention. The exposure of the immune system to vaccine formulations with the appropriate kinetics is critical for inducing protective immunity. In this work, faceted microneedle arrays were designed and fabricated utilizing a three-dimensional (3D)-printing technique called continuous liquid interface production (CLIP). The faceted microneedle design resulted in increased surface area as compared with the smooth square pyramidal design, ultimately leading to enhanced surface coating of model vaccine components (ovalbumin and CpG). Utilizing fluorescent tags and live-animal imaging, we evaluated in vivo cargo retention and bioavailability in mice as a function of route of delivery. Compared with subcutaneous bolus injection of the soluble components, microneedle transdermal delivery not only resulted in enhanced cargo retention in the skin but also improved immune cell activation in the draining lymph nodes. Furthermore, the microneedle vaccine induced a potent humoral immune response, with higher total IgG (Immunoglobulin G) and a more balanced IgG1/IgG2a repertoire and achieved dose sparing. Furthermore, it elicited T cell responses as characterized by functional cytotoxic CD8⁺ T cells and CD4⁺ T cells secreting Th1 (T helper type 1)-cytokines. Taken together, CLIP 3D-printed microneedles coated with vaccine components provide a useful platform for a noninvasive, self-applicable vaccination.

ATP stabilised and sensitised calcium phosphate nanoparticles as effective adjuvants for a DNA vaccine against cancer

Cancer vaccines based on DNA encoding oncogenes have shown great potential in preclinical studies. However, the efficacy of DNA vaccines is limited by their weak immunogenicity because of low cellular internalisation and insufficient activation of dendritic cells (DCs). Calcium phosphate (CP) nanoparticles (NPs) are biodegradable vehicles with low toxicity and high loading capacity of DNA but suffer from stability issues. Here we employed adenosine triphosphate (ATP) as a dual functional agent, i.e. stabiliser for CP and immunological adjuvant, and applied the ATP-modified CP (ACP) NPs to the DNA vaccine. ACP NP-enhanced cellular uptake and improved transfection efficiency of DNA vaccine, and further showed the ability to activate DCs that are critical for them to prime T cells in cancer immunotherapy. As a result, a higher level of antigen-specific antibody with stronger tumour growth inhibition was achieved in mice immunised with the ACP-DNA vaccine. Overall, this one-step synthesised ACP NPs are an efficient nano-delivery system and nano-adjuvant for cancer DNA vaccines.

Distinct endocytosis and immune activation of poly(lactic-co-glycolic) acid nanoparticles prepared by single- and double-emulsion evaporation

Background: Poly(lactic-co-glycolic) acid (PLGA) nanoparticles can be prepared by emulsion-solvent-evaporation from o/w and w₁/o/w₂ emulsions. Aims: To elaborate similarities and differences regarding mechanical, morphological and physicochemical properties, as well as endocytosis and dose-dependent immune responses by primary human leukocytes between nanoparticles prepared by these two methods. Methods: Fluorescently labeled as well as TLR agonist (R848)-loaded PLGA nanoparticles were prepared via both single- and double-emulsion solvent evaporation. Results: Particles prepared by both methods were similar in chemical composition and surface charge but exhibited slight differences in size and morphology. Pronounced differences were found for loading, dissolution and mechanical properties. The particles were differently endocytosed by monocytes and induced qualitatively and quantitatively different immune responses. Conclusions: Variations in nanoparticle preparation can affect particle-derived immunological characteristics.

Mechanism of a COVID-19 nanoparticle vaccine candidate that elicits a broadly neutralizing antibody response to SARS-CoV-2 variants

Vaccines that induce potent neutralizing antibody (NAb) responses against emerging variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are essential for combating the coronavirus disease 2019 (COVID-19) pandemic. We demonstrated that mouse plasma induced by self-assembling protein nanoparticles (SApNPs) that present 20 rationally designed S2GΔHR2 spikes of the ancestral Wuhan-Hu-1 strain can neutralize the B.1.1.7, B.1.351, P.1, and B.1.617 variants with the same potency. The adjuvant effect on vaccine-induced immunity was investigated by testing 16 formulations for the multilayered I3-01v9 SApNP. Using single-cell sorting, monoclonal antibodies (mAbs) with diverse neutralization breadth and potency were isolated from mice immunized with the receptor binding domain (RBD), S2GΔHR2 spike, and SApNP vaccines. The mechanism of vaccine-induced immunity was examined in mice. Compared with the soluble spike, the I3-01v9 SApNP showed 6-fold longer retention, 4-fold greater presentation on follicular dendritic cell dendrites, and 5-fold stronger germinal center reactions in lymph node follicles.

Advances and Perspectives in the Use of Carbon Nanotubes in Vaccine Development

Advances in nanobiotechnology have allowed the utilization of nanotechnology through nanovaccines. Nanovaccines are powerful tools for enhancing the immunogenicity of a specific antigen and exhibit advantages over other adjuvant approaches, with features such as expanded stability, prolonged release, decreased immunotoxicity, and immunogenic selectivity. We introduce recent advances in carbon nanotubes (CNTs) to induce either a carrier effect as a nanoplatform or an immunostimulatory effect. Several studies of CNT-based nanovaccines revealed that due to the ability of CNTs to carry immunogenic molecules, they can act as nonclassical vaccines, a quality not possessed by vaccines with traditional formulations. Therefore, adapting and modifying the physicochemical properties of CNTs for use in vaccines may additionally enhance their efficacy in inducing a T cell-based immune response. Accordingly, the purpose of this study is to renew and awaken interest in and knowledge of the safe use of CNTs as adjuvants and carriers in vaccines.

Aliphatic Polyester-Based Materials for Enhanced Cancer Immunotherapy

Poly(lactic acid) (PLA) and its copolymer, poly(lactic-co-glycolic acid) (PLGA), based aliphatic polyesters have been extensively used for biomedical applications, such as drug delivery system and tissue engineering, thanks to their biodegradability, benign toxicity, renewability, and adjustable mechanical properties. A rapidly growing field of cancer research, the development of therapeutic cancer vaccines or treatment modalities is aimed to deliver immunomodulatory signals that control the quality of immune responses against tumors. Herein, the progress and applications of PLA and PLGA are reviewed in delivering immunotherapeutics to treat cancers.

Non-viral COVID-19 vaccine delivery systems

The novel corona virus termed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread throughout the globe at a formidable speed, causing tens of millions of cases and more than one million deaths in less than a year of its report in December 2019. Since then, companies and research institutions have raced to develop SARS-CoV-2 vaccines, ranging from conventional viral and protein-based vaccines to those that are more cutting edge, including DNA- and mRNA-based vaccines. Each vaccine exhibits a different potency and duration of efficacy, as determined by the antigen design, adjuvant molecules, vaccine delivery platforms, and immunization method. In this review, we will introduce a few of the leading non-viral vaccines that are under clinical stage development and discuss delivery strategies to improve vaccine efficacy, duration of protection, safety, and mass vaccination.

Cancer Immunotherapy and Application of Nanoparticles in Cancers Immunotherapy as the Delivery of Immunotherapeutic Agents and as the Immunomodulators

Simple Summary

Cancer becomes one of the major public health problems globally and the burden is expected to be increasing. Currently, both the medical and research communities have attempted an approach to nonconventional cancer therapies that can limit damage or loss of healthy tissues and be able to fully eradicate the cancer cells. In the last few decades, cancer immunotherapy becomes an important tactic for cancer treatment. Immunotherapy of cancer must activate the host’s anti-tumor response by enhancing the innate immune system and the effector cell number, while, minimizing the host’s suppressor mechanisms. However, many immunotherapies are still limited by poor therapeutic targeting and unwanted side effects. Hence, a deeper understanding of tumor immunology and antitumor immune responses is essential for further improvement of cancer immunotherapy. In addition, effective delivery systems are required to deliver immunotherapeutic agents to the site of interest (such as: to Tumor microenvironments, to Antigen-Presenting Cells, and to the other immune systems) to enhance their efficacy by minimizing off-targeted and unwanted cytotoxicity.

Abstract

In the last few decades, cancer immunotherapy becomes an important tactic for cancer treatment. However, some immunotherapy shows certain limitations including poor therapeutic targeting and unwanted side effects that hinder its use in clinics. Recently, several researchers are exploring an alternative methodology to overcome the above limitations. One of the emerging tracks in this field area is nano-immunotherapy which has gone through rapid progress and revealed considerable potentials to solve limitations related to immunotherapy. Targeted and stimuli-sensitive biocompatible nanoparticles (NPs) can be synthesized to deliver immunotherapeutic agents in their native conformations to the site of interest to enhance their antitumor activity and to enhance the survival rate of cancer patients. In this review, we have discussed cancer immunotherapy and the application of NPs in cancer immunotherapy, as a carrier of immunotherapeutic agents and as a direct immunomodulator.

Polymeric nanoparticle vaccines to combat emerging and pandemic threats

Subunit vaccines are more advantageous than live attenuated vaccines in terms of safety and scale-up manufacture. However, this often comes as a trade-off to their efficacy. Over the years, polymeric nanoparticles have been developed to improve vaccine potency, by engineering their physicochemical properties to incorporate multiple immunological cues to mimic pathogenic microbes and viruses. This review covers recent advances in polymeric nanostructures developed toward particulate vaccines. It focuses on the impact of microbe mimicry (e.g. size, charge, hydrophobicity, and surface chemistry) on modulation of the nanoparticles’ delivery, trafficking, and targeting antigen-presenting cells to elicit potent humoral and cellular immune responses. This review also provides up-to-date progresses on rational designs of a wide variety of polymeric nanostructures that are loaded with antigens and immunostimulatory molecules, ranging from particles, micelles, nanogels, and polymersomes to advanced core-shell structures where polymeric particles are coated with lipids, cell membranes, or proteins.

Metabolic labeling and targeted modulation of dendritic cells

Targeted immunomodulation of dendritic cells (DCs) in vivo will enable manipulation of T-cell priming and amplification of anticancer immune responses, but a general strategy has been lacking. Here we show that DCs concentrated by a biomaterial can be metabolically labelled with azido groups in situ, which allows for their subsequent tracking and targeted modulation over time. Azido-labelled DCs were detected in lymph nodes for weeks, and could covalently capture dibenzocyclooctyne (DBCO)-bearing antigens and adjuvants via efficient Click chemistry for improved antigen-specific CD8⁺ T-cell responses and antitumour efficacy. We also show that azido labelling of DCs allowed for in vitro and in vivo conjugation of DBCO-modified cytokines, including DBCO-IL-15/IL-15Rα, to improve priming of antigen-specific CD8⁺ T cells. This DC labelling and targeted modulation technology provides an unprecedented strategy for manipulating DCs and regulating DC-T-cell interactions in vivo.

Advanced nanomedicines for the treatment of inflammatory diseases

Inflammation, a common feature of many diseases, is an essential immune response that enables survival and maintains tissue homeostasis. However, in some conditions, the inflammatory process becomes detrimental, contributing to the pathogenesis of a disease. Targeting inflammation by using nanomedicines (i.e. nanoparticles loaded with a therapeutic active principle), either through the recognition of molecules overexpressed onto the surface of activated macrophages or endothelial cells, or through enhanced vasculature permeability, or even through biomimicry, offers a promising solution for the treatment of inflammatory diseases. After providing a brief insight on the pathophysiology of inflammation and current therapeutic strategies, the review will discuss, at a pre-clinical stage, the main innovative nanomedicine approaches that have been proposed in the past five years for the resolution of inflammatory disorders, finally focusing on those currently in clinical trials.

Controlling timing and location in vaccines

Vaccines are one of the most powerful technologies supporting public health. The adaptive immune response induced by immunization arises following appropriate activation and differentiation of T and B cells in lymph nodes. Among many parameters impacting the resulting immune response, the presence of antigen and inflammatory cues for an appropriate temporal duration within the lymph nodes, and further within appropriate subcompartments of the lymph nodes– the right timing and location– play a critical role in shaping cellular and humoral immunity. Here we review recent advances in our understanding of how vaccine kinetics and biodistribution impact adaptive immunity, and the underlying immunological mechanisms that govern these responses. We discuss emerging approaches to engineer these properties for future vaccines, with a focus on subunit vaccines.

Enabling sublingual peptide immunization with molecular self-assemblies

Short peptides are poorly immunogenic when delivered sublingually - under the tongue. Nanomaterial delivery of peptides could be utilized to improve immunogenicity towards designed sublingual vaccines, but nanomaterials have not been widely successful in sublingual vaccines owing to the challenges of transport through the sublingual mucosa. Here, we report that the sublingual immunogenicity of peptides is negligible, even in the presence of sublingual adjuvants or when PEGylated, but can be dramatically enhanced by assembly into supramolecular polymer-peptide nanofibers bearing low-molecular weight PEG, optimally between 2000 and 3000 Da. Neither PEGylation nor a sublingual adjuvant were capable of rendering peptides immunogenic without assembly into nanofibers. We found that PEG decreased nanofiber interactions with mucin and promoted longer residence time at the sublingual immunization site. Parallel investigations with shortened nanofibers indicated that the size of the assemblies had a surprisingly negligible influence over sublingual immunogenicity. In mice, optimized formulations were capable of raising strong and highly durable systemic antibody responses, antibodies in the upper respiratory and reproductive tracts, and systemic antigen-specific T-cell responses. These nanofiber-based sublingual vaccines were effective with both protein and nucleotide adjuvants and raised responses against both a model peptide epitope and a peptide epitope from M. tuberculosis. Further, PASylation (modification of nanofibers with peptide sequences rich in Pro, Ala, and Ser) could be substituted for PEGylation to also achieve sublingual immunogenicity. These findings indicated that surface properties supersede nanomaterial size in modulating sublingual nanomaterial immunogenicity, having important implications for the design of synthetic sublingual vaccines.

Sugar-Nanocapsules Imprinted with Microbial Molecular Patterns for mRNA Vaccination

Innate immune cells recognize and respond to pathogen-associated molecular patterns. In particular, polysaccharides found in the microbial cell wall are potent activators of dendritic cells (DCs). Here, we report a new class of nanocapsules, termed sugar-capsules, entirely composed of polysaccharides derived from the microbial cell wall. We show that sugar-capsules with a flexible polysaccharide shell and a hollow core efficiently drain to lymph nodes and activate DCs. In particular, sugar-capsules composed of mannan (Mann-capsule) carrying mRNA (mRNA) promote strong DC activation, mRNA translation, and antigen presentation on DCs. Mann-capsules elicit robust antigen-specific CD4+ and CD8α+ T-cell responses with antitumor efficacy in vivo. The strategy presented in this study is generally applicable for utilizing pathogen-derived molecular patterns for vaccines and immunotherapies.

Critical design criteria for engineering a nanoparticulate HIV-1 vaccine

Inducing a long-lasting as well as broad and potent immune response by generating broadly neutralizing antibodies is a major goal and at the same time the main challenge of preventive HIV-1 vaccine design. Immunization with soluble, stabilized and native-like envelope (Env) glycoprotein so far only led to low neutralization breadth and displayed low immunogenicity. A promising approach to generate a potent immune response is the presentation of Env on the surface of nanoparticles. In this review, we will focus on two key processes essential for the induction of immune response that can be addressed by specific features of nanoparticulate carriers: first, the trafficking to and within distinct compartments of the lymph node, and second, the use of multivalent Env display allowing for high avidity interactions. To optimize these pivotal steps critical design criteria should be considered for the presentation of Env on nanoparticles. These include an optimal particle size below 100 nm, distances between two adjacent Env antigens of approximately 10-15 nm, an appropriate orientation of Env, and finally, the stability of both the Env attachment and the nanoparticle platform. Hence, an interdisciplinary approach that combines a suitable delivery system and a straightforward presentation of the Env antigen may have the potential to drive the immune response towards increased breadth and potency.

Design of polymeric nanocapsules to improve their lympho-targeting capacity

Aim: To design lympho-targeted nanocarriers with the capacity to enhance the activity of associated drugs/antigens whose target is within the lymphatic system. Materials & methods: Inulin (INU)-based nanocapsules (NCs), negatively charged and positively charged chitosan NCs were prepared by the solvent displacement techniques. The NCs were produced in two sizes: small (70 nm) and medium (170-250 nm). Results: In vitro results indicated that small NCs interacted more efficiently with dendritic cells than the larger ones. The study of the NCs biodistribution in mice, using 3D reconstruction of the popliteal lymph node, showed that small INU NCs have the greatest access and uniform accumulation in different subsets of resident immune cells. Conclusion: Small and negatively charged INU NCs have a potential as lympho-targeted antigen/drug nanocarriers.

Nanoparticle Size Influences Antigen Retention and Presentation in Lymph Node Follicles for Humoral Immunity

Lymph node follicles capture and retain antigens to induce germinal centers and long-lived humoral immunity. However, control over antigen retention has been limited. Here we discovered that antigen conjugated to nanoparticle carriers of different sizes impacts the intralymph node transport and specific cell interaction. We found that follicular dendritic cell (FDC) networks determine the intralymph node follicle fate of these nanoparticles by clearing smaller ones (5-15 nm) within 48 h and retaining larger ones (50-100 nm) for over 5 weeks. The 50-100 nm-sized nanoparticles had 175-fold more delivery of antigen at the FDC dendrites, 5-fold enhanced humoral immune responses of germinal center B cell formation, and 5-fold more antigen-specific antibody production over 5-15 nm nanoparticles. Our results show that we can tune humoral immunity by simply manipulating the carrier size design to produce effectiveness of vaccines.

Review of polysaccharide particle-based functional drug delivery

This review investigates the significant role polysaccharide particles play in functional drug delivery. The importance of these systems is due to the wide variety of polysaccharides and their natural source meaning that they can provide biocompatible and biodegradable systems with a range of both biological and chemical functionality valuable for drug delivery. This functionality includes protection and presentation of working therapeutics through avoidance of the reticuloendothelial system, stabilization of biomacromolecules and increasing the bioavailability of incorporated small molecule drugs. Transport of the therapeutic is also key to the utility of polysaccharide particles, moving drugs from the site of administration through mucosal binding and transport and using chemistry, size and receptor mediated drug targeting to specific tissues. This review also scrutinizes the methods of synthesizing and constructing functional polysaccharide particle drug delivery systems that maintain and extend the functionality of the natural polysaccharides.

PCSK9 Hapten Multicopy Displayed onto Carrier Protein Nanoparticle: An Antiatherosclerosis Vaccine

In recent years, various vaccination strategies have shed new light on the treatment of atherosclerosis. Proprotein convertase subtilisin/Kexin type 9 (PCSK9) is a hot target in the development of antiatherosclerosis vaccine. However, the efficacy of conventional PCSK9 is largely limited by poor immunogenicity and low hapten density. Therefore, we hypothesized whether a nanostructure synthesized by self-assembled carrier protein accompanied by multicopy hapten display could improve the efficacy of vaccine. In this study, bovine serum albumin (BSA) was self-assembled into sub-100 nm nanoparticles via an intermolecular disulfide network as the inner core. Then, sequences of PCSK9 were conjugated onto the surface of nanoparticles by "click" chemistry to consequently form an orderly structured of nanovaccine with repetitive hapten display. Compared with conventional PCSK9 peptide vaccine, our immunization study demonstrated that the PCSK9 multicopy display nanovaccine (PMCDN) was able to induce higher titers of PCSK9 antibody and more efficient lymph node drainage and improve endocytosis by antigen presenting cells.

Are nanotechnological approaches the future of treating inflammatory diseases?

The current treatments for chronic inflammatory diseases cause severe side effects due to nonspecific drug accumulation. Nanotechnology opens the way to new therapeutic strategies that exploit the ability of immune cells, and especially of phagocytes, to internalize nanoparticles. The cellular uptake of nanoparticles requires specific interactions and is affected by the chemical and physical properties of the carriers. Therefore, optimizing these properties is crucial for designing nanodrugs for immunotherapy. In perspective, we discuss the nanoparticle-based approaches that have been proposed to induce tolerance in autoimmune disorders and lessen the symptoms of inflammatory diseases.

National Cancer Institute Alliance for nanotechnology in cancer-Catalyzing research and translation toward novel cancer diagnostics and therapeutics

Nanotechnology has been a burgeoning research field, which is finding compelling applications in several practical areas of everyday life. It has provided novel, paradigm shifting solutions to medical problems and particularly to cancer. In order to accelerate integration of nanotechnology into cancer research and oncology, the National Cancer Institute (NCI) of the National Institutes of Health (NIH) established the NCI Alliance for Nanotechnology in Cancer program in 2005. This effort brought together scientists representing physical sciences, chemistry, and engineering working at the nanoscale with biologists and clinicians working on cancer to form a uniquely multidisciplinary cancer nanotechnology research community. The last 14 years of the program have produced a remarkable body of scientific discovery and demonstrated its utility to the development of practical cancer interventions. This paper takes stock of how the Alliance program influenced melding of disparate research disciplines into the field of nanomedicine and cancer nanotechnology, has been highly productive in the scientific arena, and produced a mechanism of seamless transfer of novel technologies developed in academia to the clinical and commercial space. This article is categorized under: Toxicology and Regulatory Issues in Nanomedicine > Regulatory and Policy Issues in Nanomedicine Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Diagnostic Tools > in vivo Nanodiagnostics and Imaging.

Mannose-Modified Multi-Walled Carbon Nanotubes as a Delivery Nanovector Optimizing the Antigen Presentation of Dendritic Cells

Dendritic cells (DCs) based cancer immunotherapy is largely dependent on adequate antigen delivery and efficient induction of DCs maturation to produce sufficient antigen presentation and ultimately lead to substantial activation of tumor-specific CD8+ T cells. Carbon nanotubes (CNTs) have attracted great attention in biomedicine because of their unique physicochemical properties. In order to effectively deliver tumor antigens to DCs and trigger a strong anti-tumor immune response, herein, a specific DCs target delivery system was assembled by using multi-walled carbon nanotubes modified with mannose which can specifically bind to the mannose receptor on DCs membrane. Ovalbumin (OVA) as a model antigen, could be adsorbed on the surface of mannose modified multi-walled carbon nanotubes (Man-MWCNTs) with a large drug loading content. This nanotube-antigen complex showed low cytotoxicity to DCs and was efficiently engulfed by DCs to induce DCs maturation and cytokine release in vitro, indicating that it could be a potent antigen-adjuvant nanovector of efficient antigen delivery for therapeutic purpose.

Tailored Polymers with Complement Activation Ability To Improve Antitumor Immunity

The complement system plays an important role in host innate immunity, and its activation can be exploited as a potential strategy for vaccine adjuvants. Herein, a pH-responsive micellar vaccine platform (COOH-NPs) was developed using a carboxyl-modified diblock copolymer of poly(2-ethyl-2-oxazoline)-poly(d,l-lactide) (COOH-PEOz-PLA). The copolymer self-assembled into micelles with hydroxyl groups shielding on the surface, which activated the complement system for the enhanced immune responses. Compared with the control nanoparticles (OCH₃-NPs), COOH-NPs significantly enhanced lymph node-resident dendritic cell maturation, antigen-specific IgG production, antigen-specific CD4⁺ and CD8⁺ T-cell activation, and the amount of memory T-cell generation in vivo. Furthermore, immunization with COOH-NPs/OVA in E.G7-OVA tumor-bearing mice not only remarkably inhibited tumor growth but also prolonged the survival of tumor-bearing mice. These results indicated that COOH-NPs with the capability of complement activation efficiently boosted the immune responses for the antitumor effect. The study demonstrated the significance of taking advantage of a complement-activating vaccine platform for cancer immunotherapy.

Link between Low-Fouling and Stealth: A Whole Blood Biomolecular Corona and Cellular Association Analysis on Nanoengineered Particles

Upon exposure to human blood, nanoengineered particles interact with a multitude of plasma components, resulting in the formation of a biomolecular corona. This corona modulates downstream biological responses, including recognition by and association with human immune cells. Considerable research effort has been directed toward the design of materials that can demonstrate a low affinity for various proteins (low-fouling materials) and materials that can exhibit low association with human immune cells (stealth materials). An implicit assumption common to bio-nano research is that nanoengineered particles that are low-fouling will also exhibit stealth. Herein, we investigated the link between the low-fouling properties of a particle and its propensity for stealth in whole human blood. High-fouling mesoporous silica (MS) particles and low-fouling zwitterionic poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) particles were synthesized, and their interaction with blood components was assessed before and after precoating with serum albumin, immunoglobulin G, or complement protein C1q. We performed an in-depth proteomics characterization of the biomolecular corona that both identifies specific proteins and measures their relative abundance. This was compared with observations from a whole blood association assay that identified with which cell type each particle system associates. PMPC-based particles displayed reduced association both with cells and with serum proteins compared with MS-based particles. Furthermore, the enrichment of specific proteins within the biomolecular corona was found to correlate with association with specific cell types. This study demonstrates how the low-fouling properties of a material are indicative of its stealth with respect to immune cell association.