Pathogen-mimicking vaccine delivery system designed with a bioactive polymer (inulin acetate) for robust humoral and cellular immune responses

In Silico-Guided Discovery of Polysaccharide Derivatives as Adjuvants in Nanoparticle Vaccines for Cancer Immunotherapy

Cancer vaccines utilizing nanoparticle (NP) structures that integrate antigens and adjuvants to enhance delivery and stimulate immune responses are emerging as a promising avenue in cancer immunotherapy. However, the development of cancer vaccines has been significantly hindered by the low immunogenicity of tumor antigens. To address this challenge, substantial efforts have been made in developing innovative adjuvants to elicit effective immune responses. In this study, we develop a NP cancer vaccine assisted by a polysaccharide derivative adjuvant, designed through a computational strategy, to evoke effective antigen-specific antitumor immunity. Using TLR4 as the putative receptor, we conducted a comprehensive evaluation of a prescreening library consisting of 34 inulin derivatives through docking and molecular dynamics simulation. Consequently, a new derivative, benzoylated inulin (InBz), is selected as the most promising TLR4 agonist. The adjuvant effect of InBz is evaluated by fabricating InBz NPs encapsulating the model antigen ovalbumin (OVA). In vitro, InBz-OVA NPs effectively activate the TLR4 signaling pathways and facilitate dendritic cell maturation, thereby enhancing the antigen delivery and presentation. In vivo, InBz-OVA NPs outperform a commercial aluminum-based adjuvant, elicit robust antibody titers, induce antigen-specific cytotoxic T lymphocytes, and achieve significant tumor suppression in murine models. Besides, the adjuvant effects of other representative derivatives, namely, acetylated and chloroacetylated inulin, with moderate and low potential from the library, are also chemically synthesized and experimentally evaluated and found to be in agreement with computational predictions, confirming the credibility of the strategy. This study provides an effective platform for the pursuit of efficient polysaccharide-based vaccine adjuvants.

Poria cocos polysaccharide-honeycomb manganese oxide nanoparticles as a vaccine adjuvant to induce potent immune responses

As indispensable components of vaccines, adjuvants play a critical role in inducing potent immune responses. In our previous study, we isolated and purified a water-soluble polysaccharide from Poria cocos (PCP), and found that the PCP had the potential to act as an immunostimulant to induce a balanced Th1/Th2 immune response. However, the PCP showed effective immunomodulatory activity only at high concentrations. Herein, we prepared a novel and biodegradable adjuvant system (PCP-hMnOx), in which the PCP was loaded onto the honeycomb manganese oxide nanoparticles (hMnOx). The developed PCP-hMnOx adjuvant system not only acted as an immunostimulant, but also as a delivery system to enhance antigen uptake by antigen-presenting cells (APCs), stimulate the activation of APCs and facilitate the formation of germinal center in draining lymph nodes. Furthermore, the PCP-hMnOx adjuvant system facilitated the antibody production, the activation of CD4+ and CD8+ T cells, and the generation of IFN-γ, thus inducing a robust and durable immune response with a balanced Th1/Th2 response in comparison to commercial alum adjuvant. Our results demonstrated that the PCP-hMnOx adjuvant system improved the immunomodulatory activity of the PCP, and had the potential to provide a simple, safe, and efficient nanoparticles-based strategy to induce potent immune responses.

Improved cellular immune response induced by intranasal boost immunization with chitosan coated DNA vaccine against H9N2 influenza virus challenge

The H9N2 avian influenza virus (AIV) is spreading worldwide. Presence of H9N2 virus tends to increase the chances of infection with other pathogens which can lead to more serious economic losses. In a previous study, a regulated delayed lysis Salmonella vector was used to deliver a DNA vaccine named pYL233 encoding M1 protein, mosaic HA protein and chicken GM-CSF adjuvant. To further increase its efficiency, chitosan as a natural adjuvant was applied in this study. The purified plasmid pYL233 was coated with chitosan to form a DNA containing nanoparticles (named CS233) by ionic gel method and immunized by intranasal boost immunization in birds primed by oral administration with Salmonella strain. The CS233 DNA nanoparticle has a particle size of about 150 nm, with an encapsulation efficiency of 93.2 ± 0.12 % which protected the DNA plasmid from DNase I digestion and could be stable for a period of time at 37°. After intranasal boost immunization, the CS233 immunized chickens elicited higher antibody response, elevated CD4+ T cells and CD8+ T cells activation and increased T-lymphocyte proliferation, as well as increased productions of IL-4 and IFN-γ. After challenge, chickens immunized with CS233 resulted in the lowest levels of pulmonary virus titer and viral shedding as compared to the other challenge groups. The results showed that the combination of intranasal immunization with chitosan-coated DNA vaccine and oral immunization with regulatory delayed lytic Salmonella strain could enhance the immune response and able to provide protection against H9N2 challenge.

A Polysaccharide-Based Oral-Vaccine Delivery System and Adjuvant for the Influenza Virus Vaccine

Influenza virus enters the host body through the mucosal surface of the respiratory tract. An efficient immune response at the mucosal site can interfere with virus entry and prevent infection. However, formulating oral vaccines and eliciting an effective mucosal immune response including at respiratory mucosa presents numerous challenges including the potential degradation of antigens by acidic gastric fluids and the risk of antigen dilution and dispersion over a large surface area of the gut, resulting in minimal antigen uptake by the immune cells. Additionally, oral mucosal vaccines have to overcome immune tolerance in the gut. To address the above challenges, in the current study, we evaluated inulin acetate (InAc) nanoparticles (NPs) as a vaccine adjuvant and antigen delivery system for oral influenza vaccines. InAc was developed as the first polysaccharide polymer-based TLR4 agonist; when tailored as a nanoparticulate vaccine delivery system, it enhanced antigen delivery to dendritic cells and induced a strong cellular and humoral immune response. This study compared the efficacy of InAc-NPs as a delivery system for oral vaccines with Poly (lactic-co-glycolic acid) (PLGA) NPs, utilizing influenza A nucleoprotein (Inf-A) as an antigen. InAc-NPs effectively protected the encapsulated antigen in both simulated gastric (pH 1.1) and intestinal fluids (pH 6.8). Moreover, InAc-NPs facilitated enhanced antigen delivery to macrophages, compared to PLGA-NPs. Oral vaccination studies in Balb/c mice revealed that InAc-Inf-A NPs significantly boosted the levels of Influenza virus-specific IgG and IgA in serum, as well as total and virus-specific IgA in the intestines and lungs. Furthermore, mice vaccinated with InAc-Inf-A-NPs exhibited notably higher hemagglutination inhibition (HI) titers at mucosal sites compared to those receiving the antigen alone. Overall, our study underscores the efficacy of InAc-NPs in safeguarding vaccine antigens post-oral administration, enhancing antigen delivery to antigen-presenting cells, and eliciting higher virus-neutralizing antibodies at mucosal sites following vaccination.

The Structural Characterization of a Polysaccharide from the Dried Root of Salvia miltiorrhiza and Its Use as a Vaccine Adjuvant to Induce Humoral and Cellular Immune Responses

In order to supplement the research gap concerning Salvia miltiorrhiza polysaccharide extracted from Danshen in NMR analysis, and to clarify its immune enhancement effect as an adjuvant, we isolated and purified SMPD-2, which is composed of nine monosaccharides such as Ara, Gal, and Glc from Danshen. Its weight average molecular weight was 37.30 ± 0.096 KDa. The main chain was mainly composed of →4)-α-D-Galp-(1→, →3,6)-β-D-Glcp-(1→ and a small amount of α-L-Araf-(1→. After the subcutaneous injection of SMPD-2 as an adjuvant to OVA in mice, we found that it enhanced the immune response by activating DCs from lymph nodes, increasing OVA-specific antibody secretion, stimulating spleen lymphocyte activation, and showing good biosafety. In conclusion, SMPD-2 could be a promising candidate for an adjuvant.

Structural characterization and adjuvant activity of a water soluble polysaccharide from Poria cocos

Adjuvants, as the essential component of vaccines, are crucial in enhancing the magnitude, breadth and durability of immune responses. Unfortunately, commonly used Alum adjuvants predominantly provoke humoral immune response, but fail to evoke cellular immune response, which is crucial for the prevention of various chronic infectious diseases and cancers. Thus, it is necessary to develop effective adjuvants to simultaneously induce humoral and cellular immune response. In this work, we obtained a water soluble polysaccharide isolated and purified from Poria cocos, named as PCP, and explored the possibility of PCP as a vaccine adjuvant. The PCP, with Mw of 20.112 kDa, primarily consisted of →6)-α-D-Galp-(1→, with a small amount of →3)-β-D-Glcp-(1 → and →4)-β-D-Glcp-(1→. Our results demonstrated that the PCP promoted the activation of dendritic cells (DCs) and macrophages in vitro. As the adjuvant to ovalbumin, the PCP facilitated the activation of DCs in lymph nodes, and evoked strong antibody response with a combination of Th1 and Th2 immune responses. Moreover, compared to Alum adjuvant, the PCP markedly induced a potent cellular response, especially the cytotoxic T lymphocytes response. Therefore, we confirmed that the PCP has great potential to be an available adjuvant for simultaneously inducing humoral and cellular immune responses.

Uptake pathways of cell-penetrating peptides in the context of drug delivery, gene therapy, and vaccine development

Cell-penetrating peptides have been extensively utilized for the purpose of facilitating the intracellular delivery of cargo that is impermeable to the cell membrane. The researchers have exhibited proficient delivery capabilities for oligonucleotides, thereby establishing cell-penetrating peptides as a potent instrument in the field of gene therapy. Furthermore, they have demonstrated a high level of efficiency in delivering several additional payloads. Cell penetrating peptides (CPPs) possess the capability to efficiently transport therapeutic molecules to specific cells, hence offering potential remedies for many illnesses. Hence, their utilization is imperative for the improvement of therapeutic vaccines. In contemporary studies, a plethora of cell-penetrating peptides have been unveiled, each characterized by its own distinct structural attributes and associated mechanisms. Although it is widely acknowledged that there are multiple pathways through which particles might be internalized, a comprehensive understanding of the specific mechanisms by which these particles enter cells has to be fully elucidated. The absorption of cell-penetrating peptides can occur through either direct translocation or endocytosis. However, it is worth noting that categories of cell-penetrating peptides are not commonly linked to specific entrance mechanisms. Furthermore, research has demonstrated that cell-penetrating peptides (CPPs) possess the capacity to enhance antigen uptake by cells and facilitate the traversal of various biological barriers. The primary objective of this work is to examine the mechanisms by which cell-penetrating peptides are internalized by cells and their significance in facilitating the administration of drugs, particularly in the context of gene therapy and vaccine development. The current study investigates the immunostimulatory properties of numerous vaccine components administered using different cell-penetrating peptides (CPPs). This study encompassed a comprehensive discussion on various topics, including the uptake pathways and mechanisms of cell-penetrating peptides (CPPs), the utilization of CPPs as innovative vectors for gene therapy, the role of CPPs in vaccine development, and the potential of CPPs for antigen delivery in the context of vaccine development.

Biomimetic nanotechnology for cancer immunotherapy: State of the art and future perspective

Cancer continues to be a significant worldwide cause of mortality. This underscores the urgent need for novel strategies to complement and overcome the limitations of conventional therapies, such as imprecise targeting and drug resistance. Cancer Immunotherapy utilizes the body's immune system to target malignant cells, reducing harm to healthy tissue. Nevertheless, the efficacy of immunotherapy exhibits variation across individuals and has the potential to induce autoimmune responses. Biomimetic nanoparticles (bNPs) have transformative potential in cancer immunotherapy, promising improved accurate targeting, immune system activation, and resistance mechanisms, while also reducing the occurrence of systemic autoimmune side effects. This integration offers opportunities for personalized medicine and better therapeutic outcomes. Despite considerable potential, bNPs face barriers like insufficient targeting, restricted biological stability, and interactions within the tumor microenvironment. The resolution of these concerns is crucial in order to expedite the integration of bNPs from the research setting into clinical therapeutic uses. In addition, optimizing manufacturing processes and reducing bNP-related costs are essential for practical implementation. The present research introduces comprehensive classifications of bNPs as well as recent achievements in their application in cancer immunotherapies, emphasizing the need to address barriers for swift clinical integration.

Proof of concept in utilizing the peptidoglycan skeleton of pathogenic bacteria as antigen delivery platform for enhanced immune response

Subunit vaccines are becoming increasingly important because of their safety and effectiveness. However, subunit vaccines often exhibit limited immunogenicity, necessitating the use of suitable adjuvants to elicit robust immune responses. In this study, we demonstrated for the first time that pathogenic bacteria can be prepared into a purified peptidoglycan skeleton without nucleic acids and proteins, presenting bacterium-like particles (pBLP). Our results showed that the peptidoglycan skeletons screened from four pathogens could activate Toll-like receptor1/2 receptors better than bacterium-like particles from Lactococcus lactis in macrophages. We observed that pBLP was safe in mouse models of multiple ages. Furthermore, pBLP improved the performance of two commercial vaccines in vivo. We confirmed that pBLP successfully loaded antigens onto the surface and proved to be an effective antigen delivery platform with enhanced antibody titers, antibody avidity, balanced subclass distribution, and mucosal immunity. These results indicate that the peptidoglycan skeleton of pathogenic bacteria represents a new strategy for developing subunit vaccine delivery systems.

Role of toll-like receptor in the pathogenesis of oral cancer

Toll-like receptors are important molecules of innate immunity. They are known as pattern recognition receptors. They recognise certain molecules known as pathogen-associated molecular pattern on a pathogen and release chemicals that causes inflammation. Toll-like receptors (TLR) help in the removal of the infected cell and thus stop the spread of infection and are being studied for their association with cancer. Oral carcinoma has emerged as a major problem of our country today; it is found ranks first in men and third in women. Toll-like receptors have been implicated in the development of cancer. Certain polymorphisms in toll-like receptor can make a cell more susceptible to develop oral cancer. The identification of toll-like receptors and the different genotypes that are involved in the development of cancer can be utilised for using them as biomarkers of the disease. The study revealed that toll-like receptors like TLR7 and TLR5 are found to have a role in suppression of oral cancer while toll-like receptors like TLR4 and TLR2 are found to be associated with the progression of oral cancer. Toll-like receptors can turn out as important target molecules in the future in designing therapeutic strategies for oral cancer.

Cancer Immunotherapy Using Bioengineered Micro/Nano Structured Hydrogels

Hydrogels, a class of materials with a 3D network structure, are widely used in various applications of therapeutic delivery, particularly cancer therapy. Micro and nanogels as miniaturized structures of the bioengineered hydrogels may provide extensive benefits over the common hydrogels in encapsulation and controlled release of small molecular drugs, macromolecular therapeutics, and even cells. Cancer immunotherapy is rapidly developing, and micro/nanostructured hydrogels have gained wide attention regarding their engineered payload release properties that enhance systemic anticancer immunity. Additionally, they are a great candidate due to their local administration properties with a focus on local immune cell manipulation in favor of active and passive immunotherapies. Although applied locally, such micro/nanostructured can also activate systemic antitumor immune responses by releasing nanovaccines safely and effectively inhibiting tumor metastasis and recurrence. However, such hydrogels are mostly used as locally administered carriers to stimulate the immune cells by releasing tumor lysate, drugs, or nanovaccines. In this review, the latest developments in cancer immunotherapy are summarized using micro/nanostructured hydrogels with a particular emphasis on their function depending on the administration route. Moreover, the potential for clinical translation of these hydrogel-based cancer immunotherapies is also discussed.

Advanced subunit vaccine delivery technologies: From vaccine cascade obstacles to design strategies

Designing and manufacturing safe and effective vaccines is a crucial challenge for human health worldwide. Research on adjuvant-based subunit vaccines is increasingly being explored to meet clinical needs. Nevertheless, the adaptive immune responses of subunit vaccines are still unfavorable, which may partially be attributed to the immune cascade obstacles and unsatisfactory vaccine design. An extended understanding of the crosstalk between vaccine delivery strategies and immunological mechanisms could provide scientific insight to optimize antigen delivery and improve vaccination efficacy. In this review, we summarized the advanced subunit vaccine delivery technologies from the perspective of vaccine cascade obstacles after administration. The engineered subunit vaccines with lymph node and specific cell targeting ability, antigen cross-presentation, T cell activation properties, and tailorable antigen release patterns may achieve effective immune protection with high precision, efficiency, and stability. We hope this review can provide rational design principles and inspire the exploitation of future subunit vaccines.

Smart Nanocarriers for the Targeted Delivery of Therapeutic Nucleic Acid for Cancer Immunotherapy

A wide variety of therapeutic approaches and technologies for delivering therapeutic agents have been investigated for treating cancer. Recently, immunotherapy has achieved success in cancer treatment. Successful clinical results of immunotherapeutic approaches for cancer treatment were led by antibodies targeting immune checkpoints, and many have advanced through clinical trials and obtained FDA approval. A major opportunity remains for the development of nucleic acid technology for cancer immunotherapy in the form of cancer vaccines, adoptive T-cell therapies, and gene regulation. However, these therapeutic approaches face many challenges related to their delivery to target cells, including their in vivo decay, the limited uptake by target cells, the requirements for nuclear penetration (in some cases), and the damage caused to healthy cells. These barriers can be avoided and resolved by utilizing advanced smart nanocarriers (e.g., lipids, polymers, spherical nucleic acids, metallic nanoparticles) that enable the efficient and selective delivery of nucleic acids to the target cells and/or tissues. Here, we review studies that have developed nanoparticle-mediated cancer immunotherapy as a technology for cancer patients. Moreover, we also investigate the crosstalk between the function of nucleic acid therapeutics in cancer immunotherapy, and we discuss how nanoparticles can be functionalized and designed to target the delivery and thus improve the efficacy, toxicity, and stability of these therapeutics.

Recent Advances in Delivery Systems for Genetic and Other Novel Vaccines

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

Toll-like receptor (TLRs) agonists and antagonists for COVID-19 treatments

Severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) rapidly infects humans and animals which make coronavirus disease 2019 (COVID-19) a grievous epidemic worldwide which broke out in 2020. According to data analysis of the other coronavirus family, for instance severe acute respiratory syndrome SARS coronavirus (SARS-CoV), can provide experience for the mutation of SARS-CoV-2 and the prevention and treatment of COVID-19. Toll-like receptors (TLRs) as a pattern recognition receptor (PRRs), have an indispensable function in identifying the invader even activate the innate immune system. It is possible for organism to activate different TLR pathways which leads to secretion of proinflammatory cytokines such as Interleukin 1 (IL-1), Interleukin 6 (IL-6), Tumor necrosis factor α (TNFα) and type Ⅰ interferon. As a component of non-specific immunity, TLRs pathway may participate in the SARS-CoV-2 pathogenic processes, due to previous works have proved that TLRs are involved in the invasion and infection of SARS-CoV and MERS to varying degrees. Different TLR, such as TLR2, TLR4, TLR7, TLR8 and TLR9 probably have a double-sided in COVID-19 infection. Therefore, it is of great significance for a correctly acknowledging how TLR take part in the SARS-CoV-2 pathogenic processes, which will be the development of treatment and prevention strategies.

Tracing New Landscapes in the Arena of Nanoparticle-Based Cancer Immunotherapy

Over the past two decades, unique and comprehensive cancer treatment has ushered new hope in the holistic management of the disease. Cancer immunotherapy, which harnesses the immune system of the patient to attack the cancer cells in a targeted manner, scores over others by being less debilitating compared to the existing treatment strategies. Significant advancements in the knowledge of immune surveillance in the last few decades have led to the development of several types of immune therapy like monoclonal antibodies, cancer vaccines, immune checkpoint inhibitors, T-cell transfer therapy or adoptive cell therapy (ACT) and immune system modulators. Intensive research has established cancer immunotherapy to be a safe and effective method for improving survival and the quality of a patient’s life. However, numerous issues with respect to site-specific delivery, resistance to immunotherapy, and escape of cancer cells from immune responses, need to be addressed for expanding and utilizing this therapy as a regular mode in the clinical treatment. Development in the field of nanotechnology has augmented the therapeutic efficiency of treatment modalities of immunotherapy. Nanocarriers could be used as vehicles because of their advantages such as increased surface areas, targeted delivery, controlled surface and release chemistry, enhanced permeation and retention effect, etc. They could enhance the function of immune cells by incorporating immunomodulatory agents that influence the tumor microenvironment, thus enabling antitumor immunity. Robust validation of the combined effect of nanotechnology and immunotherapy techniques in the clinics has paved the way for a better treatment option for cancer than the already existing procedures such as chemotherapy and radiotherapy. In this review, we discuss the current applications of nanoparticles in the development of ‘smart’ cancer immunotherapeutic agents like ACT, cancer vaccines, monoclonal antibodies, their site-specific delivery, and modulation of other endogenous immune cells. We also highlight the immense possibilities of using nanotechnology to accomplish leveraging the coordinated and adaptive immune system of a patient to tackle the complexity of treating unique disease conditions and provide future prospects in the field of cancer immunotherapy.

Potential of cell-penetrating peptides (CPPs) in delivery of antiviral therapeutics and vaccines

Viral infections are a great threat to human health. Currently, there are no effective vaccines and antiviral drugs against the majority of viral diseases, suggesting the need to develop novel and effective antiviral agents. Since the intracellular delivery of antiviral agents, particularly the impermeable molecules, such as peptides, proteins, and nucleic acids, are essential to exert their therapeutic effects, using a delivery system is highly required. Among various delivery systems, cell-penetrating peptides (CPPs), a group of short peptides with the unique ability of crossing cell membrane, offer great potential for the intracellular delivery of various biologically active cargoes. The results of numerous in vitro and in vivo studies with CPP conjugates demonstrate their promise as therapeutic agents in various medical fields including antiviral therapy. The CPP-mediated delivery of various antiviral agents including peptides, proteins, nucleic acids, and nanocarriers have been associated with therapeutic efficacy both in vitro and in vivo. This review describes various aspects of viruses including their biology, pathogenesis, and therapy and briefly discusses the concept of CPP and its potential in drug delivery. Particularly, it will highlight a variety of CPP applications in the management of viral infections.

Recent Advances in Antioxidant Polymers: From Sustainable and Natural Monomers to Synthesis and Applications

Advances in technology have led to the production of sustainable antioxidants and natural monomers for food packaging and targeted drug delivery applications. Of particular importance is the synthesis of lignin polymers, and graft polymers, dopamine, and polydopamine, inulin, quercetin, limonene, and vitamins, due to their free radical scavenging ability, chemical potency, ideal functional groups for polymerization, abundance in the natural environment, ease of production, and activation of biological mechanisms such as the inhibition of the cellular activation of various signaling pathways, including NF-κB and MAPK. The radical oxygen species are responsible for oxidative damage and increased susceptibility to cancer, cardiovascular, degenerative musculoskeletal, and neurodegenerative conditions and diabetes; such biological mechanisms are inhibited by both synthetic and naturally occurring antioxidants. The orientation of macromolecules in the presence of the plasticizing agent increases the suitability of quercetin in food packaging, while the commercial viability of terpenes in the replacement of existing non-renewable polymers is reinforced by the recyclability of the precursors (thyme, cannabis, and lemon, orange, mandarin) and marginal ecological effect and antioxidant properties. Emerging antioxidant nanoparticle polymers have a broad range of applications in tumor-targeted drug delivery, food fortification, biodegradation of synthetic polymers, and antimicrobial treatment and corrosion inhibition. The aim of the review is to present state-of-the-art polymers with intrinsic antioxidant properties, including synthesis scavenging activity, potential applications, and future directions. This review is distinct from other works given that it integrates different advances in antioxidant polymer synthesis and applications such as inulin, quercetin polymers, their conjugates, antioxidant-graft-polysaccharides, and polymerization vitamins and essential oils. One of the most comprehensive reviews of antioxidant polymers was published by Cirillo and Iemma in 2012. Since then, significant progress has been made in improving the synthesis, techniques, properties, and applications. The review builds upon existing research by presenting new findings that were excluded from previous reviews.

Toll-like Receptor-4 (TLR4) Agonist-Based Intranasal Nanovaccine Delivery System for Inducing Systemic and Mucosal Immunity

Eliciting a robust immune response at mucosal sites is critical in preventing the entry of mucosal pathogens such as influenza and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This task is challenging to achieve without the inclusion of a strong and safe mucosal adjuvant. Previously, inulin acetate (InAc), a plant-based polymer, is shown to activate toll-like receptor-4 (TLR4) and elicit a robust systemic immune response as a vaccine adjuvant. This study investigates the potential of nanoparticles prepared with InAc (InAc-NPs) as an intranasal vaccine delivery system to generate both mucosal and systemic immune responses. InAc-NPs (∼250 nm in diameter) activated wild-type (WT) macrophages but failed to activate macrophages from TLR4 knockout mice or WT macrophages when pretreated with a TLR4 antagonist (lipopolysaccharide-RS (LPS-RS)), which indicates the selective nature of a InAc-based nanodelivery system as a TLR4 agonist. Intranasal immunization using antigen-loaded InAc-NPs generated ∼65-fold and 19-fold higher serum IgG1 and IgG2a titers against the antigen, respectively, as compared to PLGA-NPs as a delivery system. InAc-NPs have also stimulated the secretion of sIgA at various mucosal sites, including nasal-associated lymphoid tissues (NALTs), lungs, and intestine, and produced a strong memory response indicative of both humoral and cellular immune activation. Overall, by stimulating both systemic and mucosal immunity, InAc-NPs laid a basis for a potential intranasal delivery system for mucosal vaccination.

Novel formulations and drug delivery systems to administer biological solids

Recent advances in formulation sciences have expanded the previously limited design space for biological modalities, including peptide, protein, and vaccine products. At the same time, the discovery and application of new modalities, such as cellular therapies and gene therapies, have presented formidable challenges to formulation scientists. We explore these challenges and highlight the opportunities to overcome them through the development of novel formulations and drug delivery systems as biological solids. We review the current progress in both industry and academic laboratories, and we provide expert perspectives in those settings. Formulation scientists have made a tremendous effort to accommodate the needs of these novel delivery routes. These include stability-preserving formulations and dehydration processes as well as dosing regimes and dosage forms that improve patient compliance.

Engineering a sustained release vaccine with a pathogen-mimicking manner for robust and durable immune responses

Sustained release vaccine carriers can facilitate an increased interaction time between the antigen and immune system to strengthen immune responses, but their promotion on adaptive immune responses, especially cellular immunity, are still unfavorable. Herein, we report a sustained antigen delivery vector, which carries abundant antigens, a nucleic acid adjuvant and pathogen-associated molecular patterns to simulate a natural pathogen to reinforce immune responses. Specifically, murine colorectal cancer cells MC38 lysate and Toll-like receptor 9 agonist CpG are loaded into yeast derived β-glucan particles (GPs). After vaccination, these particles can form a vaccine depot that continuously release the antigen similar to the traditional aluminum hydroxide gel, but recruit more immune cells and induce more cytokine secretion at the injection site. Stronger antibody responses, Th1 and Th17 biased cellular immunity and immune memory are achieved compared with aluminum hydroxide gel. More importantly, treatment with these particles significantly suppress tumor growth in a therapeutic tumor model. This work shed light on the efficacy of combining sustained antigen release with pathogen-mimicking manner in vaccine design.

Ionotropic Gelation of Chitosan Flat Structures and Potential Applications

The capability of some polymers, such as chitosan, to form low cost gels under mild conditions is of great application interest. Ionotropic gelation of chitosan has been used predominantly for the preparation of gel beads for biomedical application. Only in the last few years has the use of this method been extended to the fabrication of chitosan-based flat structures. Herein, after an initial analysis of the major applications of chitosan flat membranes and films and their usual methods of synthesis, the process of ionotropic gelation of chitosan and some recently proposed novel procedures for the synthesis of flat structures are presented.

Potential applications of hydrophobically modified inulin as an active ingredient in functional foods and drugs - A review

•

Inulin is a substance found in a wide variety of fruits, vegetables, and herbs.

•

Inulin was modified by physical and chemical means to improve functionality.

•

HMI has been used in the stability of emulsions and suspensions.

•

SCFAs inulin esters have transformed the gut microbiota and improved the bioavailability of SCFAs.

•

HMI based bioconjugates, hydrogel, and nanomicelles were used as a controlled release of drugs and vaccines.

Over the past few years, hydrophobically modified inulin (HMI) has gained considerable attention due to its multitudinous features. The targeted release of drugs remains a subject of research interest. Moreover, it is important to explore the properties of short-chain fatty acids (SCFAs) inulin esters because they are less studied. Additionally, HMI has been used to stabilize various dispersion formulations, which have been observed to be safe because inulin is generally recognized as safe (GRAS). However, the results regarding HMI-based dispersion products are dispersed throughout the literature. This comprehensive review is discussed the possible limitations regarding SCFAs inulin esters, real food dispersion formulations, and HMI drugs. The results revealed that SCFAs inulin esters can regulate the human gut microbiota and increase the biological half-life of SCFAs in the human body. This comprehensive review discusses the versatility of HMI as a promising excipient for the production of hydrophobic drugs.

Polymeric Nanoparticle-Based Vaccine Adjuvants and Delivery Vehicles

As vaccine formulations have progressed from including live or attenuated strains of pathogenic components for enhanced safety, developing new adjuvants to more effectively generate adaptive immune responses has become necessary. In this context, polymeric nanoparticles have emerged as a promising platform with multiple advantages, including the dual capability of adjuvant and delivery vehicle, administration via multiple routes, induction of rapid and long-lived immunity, greater shelf-life at elevated temperatures, and enhanced patient compliance. This comprehensive review describes advances in nanoparticle-based vaccines (i.e., nanovaccines) with a particular focus on polymeric particles as adjuvants and delivery vehicles. Examples of the nanovaccine approach in respiratory infections, biodefense, and cancer are discussed.

Immunostimulatory biomaterials to boost tumor immunogenicity

Cancer immunotherapy is exhibiting great promise as a new therapeutic modality for cancer treatment. However, immunotherapies are limited by the inability of some tumors to provoke an immune response. These tumors with a 'cold' immunological phenotype are characterized by low numbers of tumor-infiltrating lymphocytes, high numbers of immunosuppressive leukocytes (e.g. regulatory T cells, tumor-associated macrophages), and high production of immune-dampening signals (e.g. IL-10, TGF-β, IDO-1). Strategies to boost the aptitude of tumors to initiate an immune response (i.e. boost tumor immunogenicity) will turn 'cold' tumors 'hot' and augment the anti-tumor efficacy of current immunotherapies. Approaches to boost tumor immunogenicity already show promise; however, multifaceted delivery and immunobiology challenges exist. For instance, systemic delivery of many immune-stimulating agents causes off-target toxicity and/or the development of autoimmunity, limiting the administrable dose below the threshold needed to achieve efficacy. Moreover, once administered in vivo, molecules such as the nucleic acid-based agonists for many pattern recognition receptors are either rapidly cleared or degraded, and don't efficiently traffic to the intracellular compartments where the receptors are located. Thus, these nucleic acid-based drugs are ineffective without a delivery system. Biomaterials-based approaches aim to enhance current strategies to boost tumor immunogenicity, enable novel strategies, and spare dose-limiting toxicities. Here, we review recent progress to improve cancer immunotherapies by boosting immunogenicity within tumors using immunostimulatory biomaterials.

Polyethylenimine-coated PLGA nanoparticles-encapsulated Angelica sinensis polysaccharide as an adjuvant for H9N2 vaccine to improve immune responses in chickens compared to Alum and oil-based adjuvants

Inactivated H9N2 influenza vaccines required adjuvants to induce strong immune responses to protect poultry from the infections of H9N2 influenza viruses. Recently, positively charged nanoparticles-based adjuvant delivery systems have been extensively investigated as the novel vaccine adjuvant due to the protection antigens and drugs from degradation, promoting antigens and drugs uptake by antigen presenting cells (APCs), and inducing strong humoral and cellular immune responses. In this study, the immunostimulant Angelica sinensis polysaccharide (ASP) was encapsulated into Poly (lactic-co-glycolic acid) PLGA nanoparticles, and the Polyethylenimine (PEI) was coated on the nanoparticles to develop a novel adjuvant (ASP-PLGA-PEI). To further investigate the adjuvant activities of ASP-PLGA-PEI nanoparticles for H9N2 vaccines in chickens and compare the adjuvant activities of nanoparticles adjuvant and conventional adjuvants (Alum and oil-based adjuvant), the H9N2 antigen was incubated with three different adjuvants and then immunized with chickens to evaluate the ability of inducing humoral and cellular immune responses. The results revealed that compared to Alum adjuvant, ASP-PLGA-PEI nanoparticles adjuvant stimulated higher antibody responses, promoted the activation of CD4⁺ T cells and CD8⁺ T cells, increased the expression of Th1 cytokines IFN-γ. Compared to oil-based adjuvant (ISA-206), ASP-PLGA-PEI nanoparticles adjuvant induced comparable antibody immune responses at later period after immunization, improved the activation of CD4⁺ T cells and CD8⁺ T cells. Therefore, compared to Alum and oil-based adjuvant, the ASP-PLGA-PEI nanoparticles serve as an efficient adjuvant for H9N2 vaccine and have the potential to induce vigorous humoral and cellular immune responses in chickens.

The physiological functions and pharmaceutical applications of inulin: A review

Inulin (IN), a fructan-type plant polysaccharide, is widely found in nature. The major plant sources of IN include chicory, Jerusalem artichoke, dahlia etc. Studies have found that IN possessed a wide array of biological activities, e.g. as a prebiotic to improve the intestinal microbe environment, regulating blood sugar, regulating blood lipids, antioxidant, anticancer, immune regulation and so on. Currently, IN is widely used in the food and pharmaceutical industries. IN can be used as thickener, fat replacer, sweetener and water retaining agent in the food industry. IN also can be applied in the pharmaceutics as stabilizer, drug carrier, and auxiliary therapeutic agent for certain diseases such as constipation and diabetes. This paper reviews the physiological functions of IN and its applications in the field of pharmaceutics, analyzes its present research status and future research direction. This review will serve as a one-in-all resource for the researchers who are interested to work on IN.

Chemical Strategies to Boost Cancer Vaccines

Personalized cancer vaccines (PCVs) are reinvigorating vaccine strategies in cancer immunotherapy. In contrast to adoptive T-cell therapy and checkpoint blockade, the PCV strategy modulates the innate and adaptive immune systems with broader activation to redeploy antitumor immunity with individualized tumor-specific antigens (neoantigens). Following a sequential scheme of tumor biopsy, mutation analysis, and epitope prediction, the administration of neoantigens with synthetic long peptide (SLP) or mRNA formulations dramatically improves the population and activity of antigen-specific CD4+ and CD8+ T cells. Despite the promising prospect of PCVs, there is still great potential for optimizing prevaccination procedures and vaccine potency. In particular, the arduous development of tumor-associated antigen (TAA)-based vaccines provides valuable experience and rational principles for augmenting vaccine potency which is expected to advance PCV through the design of adjuvants, delivery systems, and immunosuppressive tumor microenvironment (TME) reversion since current personalized vaccination simply admixes antigens with adjuvants. Considering the broader application of TAA-based vaccine design, these two strategies complement each other and can lead to both personalized and universal therapeutic methods. Chemical strategies provide vast opportunities for (1) exploring novel adjuvants, including synthetic molecules and materials with optimizable activity, (2) constructing efficient and precise delivery systems to avoid systemic diffusion, improve biosafety, target secondary lymphoid organs, and enhance antigen presentation, and (3) combining bioengineering methods to innovate improvements in conventional vaccination, "smartly" re-educate the TME, and modulate antitumor immunity. As chemical strategies have proven versatility, reliability, and universality in the design of T cell- and B cell-based antitumor vaccines, the union of such numerous chemical methods in vaccine construction is expected to provide new vigor and vitality in cancer treatment.

A Hybrid Glioma Tumor Cell Lysate Immunotherapy Vaccine Demonstrates Good Clinical Efficacy in the Rat Model

Background

Conventional immunotherapy for glioma is not only expensive but also demonstrates less-than-desired clinical efficacy. In this study, we evaluated the immunotherapeutic efficacy of a tumor cell lysate-based hybrid glioma vaccine developed using a molecular-based approach.

Methods

First, the ability of the autologous (9L-cell lysate) and allogeneic (C6-cell lysate) vaccines against glioma, individually and in combination, to activate Fischer344 rat dendritic cells (DCs) was determined. Next, the activated DCs were co-cultured with T lymphocytes and screened for the optimal DC-to-T-cell ratio. The in vitro efficacy of the DC/T-cell vaccine formulations subjected to different immunogen treatments and co-cultured with glioma cells was evaluated based on glioma cell viability and monocyte chemoattractant protein (MCP)-2 and interferon (IFN)-γ secretion. Subsequently, the efficacy of the 9L + C6 hybrid vaccine was evaluated in 32 glioma rat models, randomly allocated to the following five treatment groups: blank control, tumor, vaccine treatment, thymosin treatment, and vaccine + thymosin treatment (combined treatment). Changes in survival duration, intracranial tumor volume, peripheral blood immune-cell (CD4+ T, CD8+ T, and natural killer [NK] cell) count, and serum cytokine (interleukin [IL]-2, IL-10) levels were assessed in these groups.

Results

The hybrid vaccine demonstrated the highest glioma cell apoptosis and the lowest cell viability and promoted MCP-2 and IFN-γ secretion in vitro. The vaccine treatment and combined treatment groups demonstrated longer survival duration, lower intracranial tumor volume, and higher immune cell glioma tissue infiltration and IL-2 secretion than the untreated tumor group, indicating the vaccine's good in vivo efficacy. Thymosin treatment had minimal effect in enhancing anti-glioma immunity.

Conclusion

We demonstrated the feasibility of combining autologous and allogeneic tumor cell lysates to stimulate specific host cell immune response against glioma cells. The good clinical efficacy of our developed glioma hybrid vaccine in rat models suggests its potential clinical application.

Induction of Robust Immune Responses by CpG-ODN-Loaded Hollow Polymeric Nanoparticles for Antiviral and Vaccine Applications in Chickens

Background

Poultry vaccine has limited choices of adjuvants and is facing severe threat of infectious diseases due to ineffective of widely used commercial vaccines. Thus, development of novel adjuvant that offers safe and effective immunity is of urgent need.

Materials and Methods

The present research engineers a novel chicken adjuvant with potent immune-potentiating capability by incorporating avian toll-like receptor 21 (TLR21) agonist CpG ODN 2007 with a poly(lactic-co-glycolic acid) (PLGA)-based hollow nanoparticle platform (CpG-NP), which subsequently assessed ex vivo and in vivo.

Results

CpG-NPs with an average diameter of 164 nm capable of sustained release of CpG for up to 96 hours were successfully prepared. With the ex vivo model of chicken bone marrow-derived dendritic cells (chBMDCs), CpG-NP was engulfed effectively and found to induce DC maturation, promoting dendrite formation and upregulation of CD40, CD80 and CCR7. In addition to enhanced expression of IL-1β, IL-6, IL-12 and IFN-γ, 53/84 immune-related genes were found to be stimulated in CpG-NP-treated chBMDCs, whereas only 39 of such genes were stimulated in free CpG-treated cells. These upregulated genes suggest immune skewing toward T helper cell 1 bias and evidence of improved mucosal immunity upon vaccination with the CpG-NP. The CpG-NP-treated chBMDCs showed protective effects to DF-1 cells against avian influenza virus H6N1 infection. Upon subsequent coupling with infectious bronchitis virus subunit antigen administration, chickens were immunostimulated to acquire higher humoral immune response and protective response against viral challenge.

Conclustion

This work presents a novel hollow CpG-NP formulation, demonstrating effective and long-lasting immunostimulatory ability ex vivo and in vivo for chickens, as systemically compared to free CpG. This enhanced immune stimulation benefits from high stability and controlled release of internal component of nanoparticles that improve cellular delivery, lymphoid organ targeting and sustainable DC activation. CpG-NP has broad application potential in antiviral and vaccine development.

Integrating Biomaterials and Immunology to Improve Vaccines Against Infectious Diseases

Despite the success of vaccines in preventing many infectious diseases, effective vaccines against pathogens with ongoing challenges - such as HIV, malaria, and tuberculosis - remain unavailable. The emergence of new pathogen variants, the continued prevalence of existing pathogens, and the resurgence of yet other infectious agents motivate the need for new, interdisciplinary approaches to direct immune responses. Many current and candidate vaccines, for example, are poorly immunogenic, provide only transient protection, or create risks of regaining pathogenicity in certain immune-compromised conditions. Recent advances in biomaterials research are creating new potential to overcome these challenges through improved formulation, delivery, and control of immune signaling. At the same time, many of these materials systems - such as polymers, lipids, and self-assembly technologies - may achieve this goal while maintaining favorable safety profiles. This review highlights ways in which biomaterials can advance existing vaccines to safer, more efficacious technologies, and support new vaccines for pathogens that do not yet have vaccines. Biomaterials that have not yet been applied to vaccines for infectious disease are also discussed, and their potential in this area is highlighted.

Chitosan Derivatives and Their Application in Biomedicine

Chitosan is a product of the deacetylation of chitin, which is widely found in nature. Chitosan is insoluble in water and most organic solvents, which seriously limits both its application scope and applicable fields. However, chitosan contains active functional groups that are liable to chemical reactions; thus, chitosan derivatives can be obtained through the chemical modification of chitosan. The modification of chitosan has been an important aspect of chitosan research, showing a better solubility, pH-sensitive targeting, an increased number of delivery systems, etc. This review summarizes the modification of chitosan by acylation, carboxylation, alkylation, and quaternization in order to improve the water solubility, pH sensitivity, and the targeting of chitosan derivatives. The applications of chitosan derivatives in the antibacterial, sustained slowly release, targeting, and delivery system fields are also described. Chitosan derivatives will have a large impact and show potential in biomedicine for the development of drugs in future.

Biomimic strategies for modulating the interaction between particle adjuvants and antigen-presenting cells

The design strategies of particle adjuvants by mimicking natural pathogens to strengthen their interaction with antigen-presenting cells.

Nanotechnology platforms for cancer immunotherapy

Various cancer therapies have advanced remarkably over the past decade. Unlike the direct therapeutic targeting of tumor cells, cancer immunotherapy is a new strategy that boosts the host's immune system to detect specific cancer cells for efficient elimination. Nanoparticles incorporating immunomodulatory agents can activate immune cells and modulate the tumor microenvironment to enhance antitumor immunity. Such nanoparticle-based cancer immunotherapies have received considerable attention and have been extensively studied in recent years. This review thus focuses on nanoparticle-based platforms (especially naturally derived nanoparticles and synthetic nanoparticles) utilized in recent advances; summarizes delivery systems that incorporate various immune-modulating agents, including peptides and nucleic acids, immune checkpoint inhibitors, and other small immunostimulating agents; and introduces combinational cancer immunotherapy with nanoparticles, especially nanoparticle-based photo-immunotherapy and nanoparticle-based chemo-immunotherapy. Undoubtedly, the recent studies introduced in this review prove that nanoparticle-incorporated cancer immunotherapy is a highly promising treatment modality for patients with cancer. Nonetheless further research is needed to solve safety concerns and improve efficacy of nanoplatform-based cancer immunotherapy for future clinical application. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Antigen uptake and immunoadjuvant activity of pathogen-mimetic hollow silica particles conjugated with β-glucan

The aim of vaccines is to imitate the immune responses induced by pathogen infection without causing disease. Therefore, strategies of designing vaccine delivery systems by mimicking key features of pathogens are often used. For this purpose, the present study prepares pathogen-mimicking β-glucan-conjugated hollow silica particles by using polystyrene or bacteria particles as templates. The particles perfectly duplicate the structure and morphology of pathogens and possess excellent properties of hollow silica particles, including large opening pore channels, large interior cavities, high loading of OVA (ovalbumin) and controlled release capability, biocompatibility, tunability of surface functionality and immunopotentiating activity. In addition, the particles are antigen presenting cells (APCs) targeted by specific interaction with β-glucan specific receptors on the surface of APCs, which can enhance the uptake and sustained proteolytic processing of antigens and induce APC maturation. Eventually, potent Th1 and Th2-type immune responses are aroused. The size and shape of the particles have a significant impact on the antigen uptake and immunoadjuvant activity. The degree of antigen uptake enhancement is ranked in the following order: PS HSP@glucan (nanoscale spherical) > E. coli HSP@glucan (micron-sized rod-like) > S. aureus HSP@glucan (micron-sized spherical). The PS HSP@glucan is more apt to induce a Th1-type immune response, while the E. coli HSP@glucan is more apt to induce a Th2-type immune response. The particles may thus provide a promising strategy for development of novel vaccine delivery systems for inducing robust humoral and cellular immune responses against infectious diseases and cancers.

Dendritic Cell-Targeted Nanovaccine Delivery System Prepared with an Immune-Active Polymer

Targeting dendritic cells (DCs), either ex vivo (Ex. Sipuleucel-T) or in vivo, for stimulating cellular immunity has been a leading approach for cancer vaccines. We have rationally engineered a nanoparticle (NP)-based delivery system for vaccines (InAc-NPs) using inulin acetate (InAc) as the polymer to target DCs. The material and the antigen-encapsulated InAc-NPs (∼190 nm in diameter) were characterized for their physicochemical properties. As a potent vaccine adjuvant, InAc-NPs activated TLR4 on multiple immune cells, including DCs and primary swine and human cells, to secrete various cytokines as detected by enzyme-linked immunosorbent assay and quantitative polymerase chain reaction. In addition, InAc-NPs promoted the maturation of DCs as observed by a decreased phagocytic ability and enhanced capability to activate various maturation markers (MHC-I, MHC-II, CD40, and CD80) quantified using flow cytometry. In mice, the InAc-NPs produced strong serum antibody titers (total IgG, IgG1, and IgG2a) against the encapsulated antigen (ovalbumin) similar to complete Freund's adjuvant. Additionally, as a dose-sparing delivery system, antigen delivered through InAc-NPs generated higher antibody titers (IgG1, 1.57 times; IgG-total, 1.66 times; and IgG2a, 29.8 times) even at 100 times less antigen dose. High amounts of cytokines representing both humoral (IL4 and IL10) and cell-mediated (IL2 and IFN-γ) immunities were secreted from splenocytes of mice immunized with InAc-NPs. Importantly, InAc-NPs provided complete protection in 100% of the vaccinated mice from metastasis of intravenously injected melanoma cells (B₁₆-F₁₀) to lungs. In addition, the InAc-NPs were cleared from the injection site within 30 h of injection (in vivo imaging) and displayed no toxicity at the injection site (histology). The current study demonstrates that the multifunctional InAc-based nanovaccine delivery system has potential applications in cancer immunotherapy and delivering vaccines against various infectious diseases.