Biomaterials for nanoparticle vaccine delivery systems

Lentinan PLGA-stabilized pickering emulsion for the enhanced vaccination

Lentinan (LNT), a β-1,3-linked-d-glucan with β-1,6 glucose branches, is the main bioactive component extracted from Lentinus edodes. As a carbohydrate polymer, it has attracted increasingly attention because of immune enhancement effect. Pickering emulsion has been widely used in biomedicine due to its great stability, high loading capacity, and appreciable biocompatibility. The aim of this study is to construct an adjuvant delivery system (LNTPP/OVA) (Lentinan PLGA-stabilized Pickering emulsion loading OVA antigen) which can enhance the immune activity of LNT and can together deliver model protein antigen ovalbumin (OVA) into the organism. The characterization of the LNTPP/OVA was demonstrated that the size of LNTPP/OVA was around 1050.68 nm and was stable to store at least 28 days. Pickering emulsion was spherical shape like the raspberry with the high antigen load rate at around 82.53%. Moreover, the adjuvant effect of LNTPP/OVA formulation was detected. Compared with LNT/OVA formulation, our experimental results showed that LNTPP/OVA could promote the uptake of the OVA-antigen by macrophages in vitro. In vivo experiments, LNTPP/OVA facilitated the activation of dendritic cells (DCs) and induced strong humoral and cellular immune responses carrying a Th1 and Th2 immune responses. Therefore, LNTPP/OVA formulation have the latent capacity as a vaccine transmission system.

Tetravalent formulation of Polymeric nanoparticle-based vaccine induces a potent immune response against Dengue virus

Dengue is a mosquito-borne disease caused by the four serotypes of dengue virus (DENV 1-4). It is growing at an alarming rate globally, which could be partly attributed to the...

Design and Synthesis of Protein-Based Nanocapsule Vaccines

Increasing emergence of infectious diseases is driving demand for new vaccine technologies capable of improving antigen delivery and protective efficacy. Nanoparticle technology is a modern approach to antigen delivery, capable of stabilizing and increasing the amount of antigen delivered to immune cells. Protein-based nanoparticles are a biodegradable alternative to existing nanomaterials, offering a versatile and biocompatible approach to nanoparticle vaccine delivery. In this chapter, the methods for the synthesis and characterization of protein-based nanocapsule vaccines are discussed. Initially, the requirements for a suitable nanoparticle vaccine are outlined, and finally, methods for the design and synthesis of protein-based nanocapsule vaccines are explained.

Nanovaccine Delivery Approaches and Advanced Delivery Systems for the Prevention of Viral Infections: From Development to Clinical Application

Viral infections causing pandemics and chronic diseases are the main culprits implicated in devastating global clinical and socioeconomic impacts, as clearly manifested during the current COVID-19 pandemic. Immunoprophylaxis via mass immunisation with vaccines has been shown to be an efficient strategy to control such viral infections, with the successful and recently accelerated development of different types of vaccines, thanks to the advanced biotechnological techniques involved in the upstream and downstream processing of these products. However, there is still much work to be done for the improvement of efficacy and safety when it comes to the choice of delivery systems, formulations, dosage form and route of administration, which are not only crucial for immunisation effectiveness, but also for vaccine stability, dose frequency, patient convenience and logistics for mass immunisation. In this review, we discuss the main vaccine delivery systems and associated challenges, as well as the recent success in developing nanomaterials-based and advanced delivery systems to tackle these challenges. Manufacturing and regulatory requirements for the development of these systems for successful clinical and marketing authorisation were also considered. Here, we comprehensively review nanovaccines from development to clinical application, which will be relevant to vaccine developers, regulators, and clinicians.

Innovations in lymph node targeting nanocarriers

Lymph nodes are secondary lymphoid tissues in the body that facilitate the co-mingling of immune cells to enable and regulate the adaptive immune response. They are also tissues implicated in a variety of diseases, including but not limited to malignancy. The ability to access lymph nodes is thus attractive for a variety of therapeutic and diagnostic applications. As nanotechnologies are now well established for their potential in translational biomedical applications, their high relevance to applications that involve lymph nodes is highlighted. Herein, established paradigms of nanocarrier design to enable delivery to lymph nodes are discussed, considering the unique lymph node tissue structure as well as lymphatic system physiology. The influence of delivery mechanism on how nanocarrier systems distribute to different compartments and cells that reside within lymph nodes is also elaborated. Finally, current advanced nanoparticle technologies that have been developed to enable lymph node delivery are discussed.

Robust Immune Response Induced by Schistosoma mansoni TSP-2 Antigen Coupled to Bacterial Outer Membrane Vesicles

Purpose

The use of adjuvants can significantly strengthen a vaccine’s efficacy. We sought to explore the immunization efficacy of bacterial outer membrane vesicles (OMVs) displaying the Schistosoma mansoni antigen, SmTSP-2, through a biotin-rhizavidin coupling approach. The rationale is to exploit the nanoparticulate structure and the adjuvant properties of OMVs to induce a robust antigen-specific immune response, in light of developing new vaccines against S. mansoni.

Materials and Methods

OMVs were obtained from Neisseria lactamica and conjugated with biotin. The recombinant SmTSP-2 in fusion with the biotin-binding protein rhizavidin (rRzvSmTSP-2) was produced in E. coli and coupled to biotinylated OMVs to generate an OMV complex displaying SmTSP-2 on the membrane surface (OMV:rSmTSP-2). Transmission electron microscopy (TEM) and dynamic light scattering analysis were used to determine particle charge and size. The immunogenicity of the vaccine complex was evaluated in C57BL/6 mice.

Results

The rRzvSmTSP-2 protein was successfully coupled to biotinylated OMVs and purified by size-exclusion chromatography. The OMV:rSmTSP-2 nanoparticles showed an average size of 200 nm, with zeta potential around – 28 mV. Mouse Bone Marrow Dendritic Cells were activated by the nanoparticles as determined by increased expression of the co-stimulatory molecules CD40 and CD86, and the proinflammatory cytokines (TNF-α, IL-6 and IL-12) or IL-10. Splenocytes of mice immunized with OMV:rSmTSP-2 nanoparticles reacted to an in vitro challenge with SmTSP-2 with an increased production of IL-6, IL-10 and IL-17 and displayed a higher number of CD4+ and CD8+ T lymphocytes expressing IFN-γ, IL-4 and IL-2, compared to mice immunized with the antigen alone. Immunization of mice with OMV:rSmTSP-2 induced a 100-fold increase in specific anti-SmTSP-2 IgG antibody titers, as compared to the group receiving the recombinant rSmTSP-2 protein alone or even co-administered with unconjugated OMV.

Conclusion

Our results demonstrate that the SmTSP-2 antigen coupled with OMVs is highly immunogenic in mice, supporting the potential effectiveness of this platform for improved antigen delivery in novel vaccine strategies.

Continuum Modelling for Encapsulation of Anticancer Drugs inside Nanotubes

Nanotubes, such as those made of carbon, silicon, and boron nitride, have attracted tremendous interest in the research community and represent the starting point for the development of nanotechnology. In the current study, the use of nanotubes as a means of drug delivery and, more specifically, for cancer therapy, is investigated. Using traditional applied mathematical modelling, I derive explicit analytical expressions to understand the encapsulation behaviour of drug molecules into different types of single-walled nanotubes. The interaction energies between three anticancer drugs, namely, cisplatin, carboplatin, and doxorubicin, and the nanotubes are observed by adopting the Lennard–Jones potential function together with the continuum approach. This study is focused on determining a favourable size and an appropriate type of nanotube to encapsulate anticancer drugs. The results indicate that the drug molecules with a large size tend to be located inside a large nanotube and that encapsulation depends on the radius and type of the tube. For the three nanotubes used to encapsulate drugs, the results show that the nanotube radius must be at least 5.493 Å for cisplatin, 6.452 Å for carboplatin, and 10.208 Å for doxorubicin, and the appropriate type to encapsulate drugs is the boron nitride nanotube. There are some advantages to using different types of nanotubes as a means of drug delivery, such as improved chemical stability, reduced synthesis costs, and improved biocompatibility.

Chitosan modified squalene nanostructured lipid carriers as a promising adjuvant for freeze-dried ovalbumin vaccine

As immune adjuvants assisting vaccines, nanoparticle delivery systems have been widely exploited. Squalene, the major ingredient of approved adjuvant MF59, has great potential in activating immune responses. In the current study, model antigen ovalbumin (OVA) was encapsulated into squalene-based nanostructured lipid carriers (NLCs), and the chitosan, a cationic polysaccharide, was used for modifying nanoparticles to develop a functionalized and cationic nanoparticle delivery system (OVA-csNLCs). Firstly, the optimal formulation of csNLCs was successfully screened out, and had hydrodynamic diameter of 235.80 ± 5.99 nm and zeta potential of 34.90 ± 6.95 mV. Then, the generated OVA-csNLCs had no significant difference in hydrodynamic diameter and exhibited lower zeta potential of 19.03 ± 0.31 mV and high encapsulation efficiency of 83.4%. Sucrose (10%, w/w) was selected as optimal lyoprotectant, exhibiting good stability of OVA-csNLCs in the form of freeze-dried powder. More importantly, the OVA-csNLCs effectively promoted OVA antigen uptake by macrophage, significantly enhanced the level of OVA-specific IgG, and induced a Th2-based immune response in vivo. Furthermore, mice immunization experiment demonstrated that OVA-csNLCs had well biocompatibility and facilitated spleen lymphocytes proliferation. Above findings indicate that chitosan modified squalene nanostructured lipid carriers show promise as antigen delivery system and an open adjuvant platform.

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.

In situ phase transitional polymeric vaccines for improved immunotherapy

Cancer vaccines have exhibited immense potential in cancer treatment. Through activating the host's immune system, vaccines stimulate extensive functional T cells to eliminate cancer. However, the therapeutic efficacy of cancer vaccines is limited by their inferior lymph node delivery and inadequate uptake of dendritic cells. Herein, we propose an in situ phase transitional strategy on vaccine manufacturing to maximally enhance lymph node drainage while ensuring adequate dendritic cell uptake. The phase transitional vaccines, with dynamic size modulation property, retain a small size (24.4 ± 3.1 nm) during lymph node draining then transform into larger particles (483.0 ± 41.6 nm) on-site by external signal input. Results show that this strategy induced rapid and robust immune response in a mouse melanoma tumor model. Furthermore, a stronger humoral immune response was observed in mice when immunized with MHC-II restricted antigen, which demonstrated that lymph node-targeted cancer vaccine delivery could be effectively manipulated through dynamic size modulation.

Effect of SARS-CoV-2 Mutations on the Efficacy of Antibody Therapy and Response to Vaccines

SARS-CoV-2 causes severe acute respiratory syndrome, which has led to significant morbidity and mortality around the world. Since its emergence, extensive prophylactic and therapeutic countermeasures have been employed to successfully prevent the spread of COVID-19. Extensive work has been undertaken on using monoclonal antibody therapies, mass vaccination programs, and antiviral drugs to prevent and treat COVID-19. However, since antiviral drugs could take years to become widely available, immunotherapy and vaccines currently appear to be the most feasible option. In December 2020, the first vaccine against SARS-CoV-2 was approved by the World Health Organization (WHO) and, subsequently, many other vaccines were approved for use by different international regulators in different countries. Most monoclonal antibodies (mAbs) and vaccines target the SARS-CoV-2 surface spike (S) protein. Recently, mutant (or variant) SARS-CoV-2 strains with increased infectivity and virulence that evade protective host antibodies present either due to infection, antibody therapy, or vaccine administration have emerged. In this manuscript, we discuss the different monoclonal antibody and vaccine therapies available against COVID-19 and how the efficacy of these therapies is affected by the emergence of variants of SARS-CoV-2. We also discuss strategies that might help society cope with variants that could neutralize the effects of immunotherapy and escape the protective immunity conferred by vaccines.

Intranasal immunization with O-2'-Hydroxypropyl trimethyl ammonium chloride chitosan nanoparticles loaded with Newcastle disease virus DNA vaccine enhances mucosal immune response in chickens

Background

There has been a great interest in developing strategies for enhancing antigen delivery to the mucosal immune system as well as identifying mucosal active immunostimulating agents. To elevate the potential of O-2ʹ-Hydroxypropyl trimethyl ammonium chloride chitosan (O-2ʹ-HACC) as an adjuvant and mucosal immune delivery carrier for DNA vaccine, we prepared the O-2ʹ-HACC loaded with Newcastle disease virus (NDV) F gene plasmid DNA and C3d6 molecular adjuvant (O-2ʹ-HACC/pFDNA microparticles).

Results

The O-2ʹ-HACC/pFDNA exhibited a regular spherical morphology with a particle size of 202.3 ± 0.52 nm, a zeta potential of 50.8 ± 8.21 mV, encapsulation efficiency of 90.74 ± 1.10%, and a loading capacity of 49.84 ± 1.20%. The plasmid DNA could be sustainably released from the O-2ʹ-HACC/pFDNA after an initial burst release. Intranasal vaccination of chickens immunized with O-2ʹ-HACC/pFDNA not only induced higher anti-NDV IgG and sIgA antibody titers but also significantly promoted lymphocyte proliferation and produced higher levels of IL-2, IL-4, IFN-γ, CD4+, and CD8 + T lymphocytes compared with the NDV commercial live attenuated vaccine. Intranasal delivery of the O-2ʹ-HACC/pFDNA enhanced humoral, cellular, and mucosal immune responses and protected chickens from the infection of highly virulent NDV compared with the intramuscular delivery.

Conclusions

Collectively, our findings indicated that the O-2ʹ-HACC could be used as a vaccine adjuvant and delivery system for mucosal immunity and have an immense application promise.

Graphic Abstract

Polyacrylate-GnRH Peptide Conjugate as an Oral Contraceptive Vaccine Candidate

Contraceptive vaccines are designed to elicit immune responses against major components of animal reproductive systems. These vaccines, which are most commonly administered via injection, typically target gonadotropin-releasing hormone (GnRH). However, the need to restrain animals for treatment limits the field applications of injectable vaccines. Oral administration would broaden vaccine applicability. We explored contraceptive vaccine candidates composed of GnRH peptide hormone, universal T helper PADRE (P), and a poly(methylacrylate) (PMA)-based delivery system. When self-assembled into nanoparticles, PMA-P-GnRH induced the production of high IgG titers after subcutaneous and oral administration in mice. PADRE was then replaced with pig T helper derived from the swine flu virus, and the vaccine was tested in pigs. High levels of systemic antibodies were produced in pigs after both injection and oral administration of the vaccine. In conclusion, we developed a simple peptide–polymer conjugate that shows promise as an effective, adjuvant-free, oral GnRH-based contraceptive vaccine.

Biomaterials and nanomaterials for sustained release vaccine delivery

Vaccines are considered one of the most significant medical advancements in human history, as they have prevented hundreds of millions of deaths since their discovery; however, modern travel permits disease spread at unprecedented rates, and vaccine shortcomings like thermal sensitivity and required booster shots have been made evident by the COVID-19 pandemic. Approaches to overcoming these issues appear promising via the integration of vaccine technology with biomaterials, which offer sustained-release properties and preserve proteins, prevent conformational changes, and enable storage at room temperature. Sustained release and thermal stabilization of therapeutic biomacromolecules is an emerging area that integrates material science, chemistry, immunology, nanotechnology, and pathology to investigate different biocompatible materials. Biomaterials, including natural sugar polymers, synthetic polyesters produced from biologically derived monomers, hydrogel blends, protein-polymer blends, and metal-organic frameworks, have emerged as early players in the field. This overview will focus on significant advances of sustained release biomaterial in the context of vaccines against infectious disease and the progress made towards thermally stable "single-shot" formulations. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious Disease.

Pollen-Mimetic Metal-Organic Frameworks with Tunable Spike-Like Nanostructures That Promote Cell Interactions to Improve Antigen-Specific Humoral Immunity

The exine capsules of pollen particles exhibit a variety of characteristic surface morphologies that promote their cell interactions; their use as antigen carriers for vaccination has been proposed. However, the allergy-causing substances in pollen particles may not all be removed, even by vigorous chemical treatments. To resolve this issue, this work develops systemic approaches for synthesizing pollen-mimetic metal-organic frameworks (MOFs), which comprise aluminum (Al) ions and an organic linker (2-aminoterephthalic acid), with tunable spike-like nanostructures on their surfaces. The as-synthesized MOFs act not only as a delivery vehicle that carries a model antigen (ovalbumin, OVA) but also as an adjuvant (Al). Scanning and transmission electron microscopies images reveal that the aspect ratio of the nanospikes that are grown on the MOFs can be controlled. A higher aspect ratio of the nanospikes on the MOFs is associated with greater cell attachment and faster and more efficient phagocytosis in cells, which results in greater expressions of pro-inflammatory cytokines. Consequently, a more robust immune response against the antigen of interest is elicited. These findings have broad implications for the rational design of the future antigen/adjuvant-presenting particles for vaccination.

pH-Controlled Release of Antigens Using Mesoporous Silica Nanoparticles Delivery System for Developing a Fish Oral Vaccine

The development of effective vaccines and delivery systems in aquaculture is a long-term challenge for controlling emerging and reemerging infections. Cost-efficient and advanced nanoparticle vaccines are of tremendous applicability in prevention of infectious diseases of fish. In this study, dihydrolipoamide dehydrogenase (DLDH) antigens of Vibrio alginolyticus were loaded into mesoporous silica nanoparticles (MSN) to compose the vaccine delivery system. Hydroxypropyl methylcellulose phthalate (HP55) was coated to provide protection of immunogen. The morphology, loading capacity, acid-base triggered release were characterized and the toxicity of nanoparticle vaccine was determined in vitro. Further, the vaccine immune effects were evaluated in large yellow croaker via oral administration. In vitro studies confirmed that the antigen could be stable in enzymes-rich artificial gastric fluid and released under artificial intestinal fluid environment. In vitro cytotoxicity assessment demonstrated the vaccines within 120 μg/ml have good biocompatibility for large yellow croaker kidney cells. Our data confirmed that the nanoparticle vaccine in vivo could elicit innate and adaptive immune response, and provide good protection against Vibrio alginolyticus challenge. The MSN delivery system prepared may be a potential candidate carrier for fish vaccine via oral administration feeding. Further, we provide theoretical basis for developing convenient, high-performance, and cost-efficient vaccine against infectious diseases in aquaculture.

Cationic chitosan-modified silica nanoparticles for oral delivery of protein vaccine

Mesoporous silica nanoparticles coated with Chitosan are exploited here as a potential carrier for oral vaccine delivery. Bovine serum albumin (BSA) was used as a protein antigen model to reveal the carrier property. Chitosan-coated BSA-loaded silica NPs had particle size 345 ± 60 nm with a cationic surface charge of 18.28 ± 0.71 mV. The encapsulation efficiency, drug loading was 25.34 ± 0.76 and 20.21 ± 0.48%, respectively. Transmission electron microscopy investigation showed the spherical shape of NPs, also confirmed surface coating around modified nanoparticles (NPs), and nitrogen absorption/desorption isotherm confirmed mesostructured inside the NPs. Fourier transform infrared spectroscopy did not show any physiochemical interactions between excipients and formulations. The structural stability of antigen after release from NPs was confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis, and chitosan-coated silica NPs exhibited a slow-release pattern. The results of in vivo experiments presented that chitosan-mesoporous silica NPs could induce a robust immune response in mice, indicating that chitosan-mesoporous silica NPs might be used as a promising carrier for oral vaccine delivery.

Age-Related Differences in Molecular Profiles for Immune Checkpoint Blockade Therapy

Immune checkpoint blockade (ICB) therapies have significantly improved the prognosis and shown considerable promise for cancer therapy; however, differences in ICB treatment efficacy between the elderly and young are unknown. We analyzed the studies enrolled in the meta-analysis using the deft approach, and found no difference in efficacy except melanoma patients receiving anti–PD-1 therapy. Similarly, higher treatment response rate and more favorable prognosis were observed in elderly patients in some cancer types (e.g., melanoma) with data from published ICB treatment clinical trials. In addition, we comprehensively compared immunotherapy-related molecular profiles between elderly and young patients from public trials and The Cancer Genome Atlas (TCGA), and validated these findings in several independent datasets. We discovered a divergent age-biased immune profiling, including the properties of tumors (e.g., tumor mutation load) and immune features (e.g., immune cells), in a pancancer setting across 27 cancer types. We believe that ICB treatment efficacy might vary depending on specific cancer types and be determined by both the tumor internal features and external immune microenvironment. Considering the high mutational properties in elderly patients in many cancer types, modulating immune function could be beneficial to immunotherapy in the elderly, which requires further investigation.

Immunostimulatory effect of chitosan and quaternary chitosan: A review of potential vaccine adjuvants

Vaccines have always been the most effective preventive treatment. Advancements in the field of vaccine is inseparable from adjuvants. Adjuvants are substances added to vaccines to enhance immunogenicity and induce a stronger immune response. Chitosan fascinated considerable attention as vaccine adjuvant due to its unique physicochemical and biological properties. Many studies have shown that chitosan and its derivatives can effectively activate antigen-presenting cells and induce cytokine stimulation to produce an effective immune response and promote the balance of Th1/Th2 response. Among many derivatives, the quaternized chitosan performs better. This review presents the main factors affecting the adjuvant performance of chitosan and quaternized chitosan firstly. Then, we introduced not only the immune response they may cause, but also their metabolic research in detail. Furthermore, their future prospects are forecasted. Overall, chitosan and quaternized chitosan are both promising adjuvant materials, and quaternized chitosan shows greater potential.

Efficacy of a nanoparticle vaccine administered in-ovo against Salmonella in broilers

Salmonella is a zoonotic pathogen that persists in poultry. Salmonella vaccines that can be delivered in-ovo can be cost-effective and can decrease Salmonella load in poultry. This study evaluates the efficacy of a Salmonella chitosan-nanoparticle (CNP) vaccine, administered in-ovo, in broilers. CNP vaccine was synthesized with Salmonella Enteritidis (SE) outer-membrane-proteins (OMPs) and flagellin proteins. At embryonic-d18, one-hundred-thirty-six eggs were injected with 200μl PBS or 1000μg CNP into the amniotic cavity. At d1-of-age, 132 chicks were allocated in 6 pens/treatment with 11 chicks/pen. At d7, birds were orally challenged with 1×109 CFU/bird SE. At d1, 8h-post-challenge, d14, and d21, serum anti-SE-OMPs IgY were analyzed. At d14 and d21, cloacal swabs and bile anti-SE-OMPs IgA, CD4+/CD8+-T-cell ratios, and ceca SE loads were analyzed. At d21, cecal tonsil IL-1β, IL-10, and iNOS mRNA were analyzed. Body-weight-gain (BWG) and feed-conversion-ratio (FCR) were recorded weekly. Data were analyzed by Student's t-test at P<0.05. There were no significant differences in BWG or FCR between vaccinated birds compared to control. At d1, CNP-vaccinated birds had 5.62% greater levels (P<0.05) of anti-SE-OMPs IgY, compared to control. At 8h-post-challenge, CNP-vaccinated birds had 6.39% greater levels (P<0.05) of anti-SE-OMPs IgY, compared to control. At 2wk-post-challenge, CNP-vaccinated birds had 7.34% lower levels (P<0.05) of anti-SE-OMPs IgY, compared to control. At 1wk-post-challenge, CNP-vaccinated birds had 15.30% greater levels (P<0.05) of bile anti-SE-OMPs IgA, compared to control. At d14 and d21, CNP-vaccinated birds had 0.62 and 0.85 Log10 CFU/g, decreased SE ceca load (P<0.05), respectively, compared to control. There were no significant differences in CD4+/CD8+-T-cell ratios between vaccinated birds compared to control. There were no significant differences in IL-1β, IL-10, iNOS mRNA between vaccinated birds compared to control. Findings demonstrate that the in-ovo administration of CNP vaccine can induce an antigen-specific immune response against SE and can decrease SE cecal load in broilers.

Microarray patches enable the development of skin-targeted vaccines against COVID-19

The COVID-19 pandemic is a serious threat to global health and the global economy. The ongoing race to develop a safe and efficacious vaccine to prevent infection by SARS-CoV-2, the causative agent for COVID-19, highlights the importance of vaccination to combat infectious pathogens. The highly accessible cutaneous microenvironment is an ideal target for vaccination since the skin harbors a high density of antigen-presenting cells and immune accessory cells with broad innate immune functions. Microarray patches (MAPs) are an attractive intracutaneous biocargo delivery system that enables safe, reproducible, and controlled administration of vaccine components (antigens, with or without adjuvants) to defined skin microenvironments. This review describes the structure of the SARS-CoV-2 virus and relevant antigenic targets for vaccination, summarizes key concepts of skin immunobiology in the context of prophylactic immunization, and presents an overview of MAP-mediated cutaneous vaccine delivery. Concluding remarks on MAP-based skin immunization are provided to contribute to the rational development of safe and effective MAP-delivered vaccines against emerging infectious diseases, including COVID-19.

Poly (D, L-lactide-co-glycolide) delivery system improve the protective efficacy of recombinant antigen TA4 against Eimeria tenella infection

Eimeria tenella is a protozoan parasite endemic in chickens and is one of the causative agents of avian coccidiosis. The aim of this research was to determine if poly (D, L-lactide-co-glycolide) (PLGA) nanoparticles carrying recombinant TA4 protein of E. tenella (rEtTA4) could improve the level of protective immunity against E. tenella challenge. Recombinant TA4 protein was expressed and purified. Poly (D, L-lactide-co-glycolide) loaded with rEtTA4 (PLGA-rEtTA4) nanoparticles was prepared and was delivered to 2-week-old layer chickens via intramuscular inoculation. Chickens injected with PBS and PLGA nanoparticles were served as control groups. The rEtTA4 and PLGA-rEtTA4 nanoparticles induced changes of serum cytokines, IgY levels, and T lymphocytes subpopulation, and the protective efficacy against E. tenella challenge was evaluated. Results showed that both rEtTA4 and PLGA-rEtTA4 vaccination groups induced significantly higher levels of specific EtTA4 IgY antibody and IL-17 and higher proportion of CD8⁺ T lymphocytes. However, no significant differences were observed in the proportion of CD4⁺ T lymphocytes compared with the PBS control. Chickens immunized with rEtTA4 and PLGA-rEtTA4 prominently increased the BW gains and decreased oocyst output compared with chickens immunized with PBS and PLGA after oral challenge with E. tenella. Poly (D, L-lactide-co-glycolide) encapsulated rEtTA4 nanoparticles–immunized chickens significantly induced higher levels of interferon gamma, IL-6, and IL-17 and a little bit higher proportion of CD8⁺ T lymphocytes compared with rEtTA4 subunit vaccine–immunized chickens. Thus, PLGA encapsulated rEtTA4 nanoparticles appeared to have great potential to enhance the immune response and improved the protective efficacy against E. tenella infection. Our results provided available protective subunit vaccine rEtTA4 and PLGA loaded with rEtTA4 nanoparticles against coccidiosis and suggested that PLGA nanoparticles could be an effective adjuvant to enhance the protective efficacy of rEtTA4 subunit vaccine.

Haemonchus contortus hepatocellular carcinoma-associated antigen 59 with poly (lactic-co-glycolic acid): A promising nanovaccine candidate against Haemonchus contortus infection

Hepatocellular carcinoma-associated antigen 59 (HCA59), one of significant excretory/secretory products of Haemonchus contortus (HcESPs), is identified to have immunomodulatory eff ;ects on host cells. However, protection potential of the molecule in H. contortus remains poorly understood. In this study, H. contortus recombinant HCA59 protein amalgamated with poly (lactic-co-glycolic acid) (PLGA) nanoparticle adjuvant was tested for its protection against H. contortus infection in goats. Fifteen goats were allocated into three groups. On days 0 and 14, rHCA59 group was immunized with PLGA nanoparticles encapsulated with recombinant protein HCA59 (rHCA59-PLGA) respectively. Positive control group was unvaccinated, but challenged with H. contortus third stage larvae (L3). Negative control group was unvaccinated and unchallenged with L3. Goats in rHCA59 group and positive control group were challenged with 8000 H. contortus L3 after 14 days of the second immunization. Following immunization, high level of sera IgG, IgA, and IgE, as well as significantly high production of IL-4 and IL-9 was produced in rHCA59 group. After L3 challenge, the level of IL-17 and TGF-β in rHCA59 group increased obviously. Meanwhile, the fecal eggs and the abomasal worm burdens in rHCA59 group was reduced by 44.1 % and 54.6 %, respectively. The studies suggested that rHCA59-PLGA nanoparticles conferred partial protection and could be a good candidate for the development of nanovaccines against H. contortus infection in goats.

Thinking Outside the Bug: Targeting Outer Membrane Proteins for Burkholderia Vaccines

Increasing antimicrobial resistance due to misuse and overuse of antimicrobials, as well as a lack of new and innovative antibiotics in development has become an alarming global threat. Preventative therapeutics, like vaccines, are combative measures that aim to stop infections at the source, thereby decreasing the overall use of antibiotics. Infections due to Gram-negative pathogens pose a significant treatment challenge because of substantial multidrug resistance that is acquired and spread throughout the bacterial population. Burkholderia spp. are Gram-negative intrinsically resistant bacteria that are responsible for environmental and nosocomial infections. The Burkholderia cepacia complex are respiratory pathogens that primarily infect immunocompromised and cystic fibrosis patients, and are acquired through contaminated products and equipment, or via patient-to-patient transmission. The Burkholderia pseudomallei complex causes percutaneous wound, cardiovascular, and respiratory infections. Transmission occurs through direct exposure to contaminated water, water-vapors, or soil, leading to the human disease melioidosis, or the equine disease glanders. Currently there is no licensed vaccine against any Burkholderia pathogen. This review will discuss Burkholderia vaccine candidates derived from outer membrane proteins, OmpA, OmpW, Omp85, and Bucl8, encompassing their structures, conservation, and vaccine formulation.

Development and evaluation of polymeric nanoparticles as a delivery system for snake envenoming prevention

Polymer-based nanoparticles have become an appealing carrier for improving vaccine delivery efficiency. In this study, we investigated an interesting approach based on PLGA nanoparticles encapsulating Cerastes cerastes venom as an intranasal vaccine delivery system for snake envenomation prevention. Particles were synthesized by double emulsion solvent evaporation method and characterized for their size, morphology, distribution, and venom-nanoparticles interactions. An immunization trial was performed in mice by the intranasal route to evaluate the immune response, the reactogenicity, and the protective effect of this nanovaccine. The physicochemical and structural characteristics of Cc-loaded PLGA NPs revealed that the particles exhibited a spherical shape with a diameter of 370 nm, and a negatively charged surface with a zeta potential value of 19,9 mV. The immunization with Cc-PLGA NPs can induce a systemic innate and humoral immune response and confers protection against Cerastes cerastes venom (Cc) over than 6 LD50 with a cross-protection against Vipera lebetina venom (Vl) over than 5 LD50. Nano-encapsulation of Cc venom reduced its toxicity and the induced tissue alterations. Our results confirm that the nano-formulation Cc-PLGA NPs is a potent adjuvant system that improve the humoral immune response and provide protection against high lethal doses of viper venoms.

Toll-like Receptor 9 Agonists as Adjuvants for Nanoparticle-Based Nicotine Vaccine

Nicotine vaccine was considered a promising therapy against smoking addiction. The level of immune response that a nicotine vaccine can induce is pivotal to its efficacy. In this study, Toll-like receptor 9 agonists, namely, CpG ODN 1555 and CpG ODN 1826, were incorporated into a nanoparticle-based nicotine vaccine (NanoNicVac) to enhance its immunogenicity. The results showed that NanoNicVac containing either CpG ODN 1555 or CpG ODN 1826 could be rapidly internalized by dendritic cells. In mice trials, it was found that NanoNicVac with CpG ODN 1555 and CpG ODN 1826 induced 3.3- and 3.2-fold higher anti-nicotine antibody titer than that by the native NanoNicVac after two injections, respectively. Instead of enhancing the immunogenicity of the vaccine, however, mixtures of the two CpG ODNs were observed to exert an immune-suppressing effect on NanoNicVac. Finally, the histopathological examination on major organs of the mice immunized with the NanoNicVacs proved that NanoNicVac with either CpG ODN 1555 or CpG ODN 1826 as adjuvants did not cause detectable toxicity to the mice.

A review article on nanotechnology in aquaculture sustainability as a novel tool in fish disease control

In recent decades, aquaculture has played a significant role in fulfilling the vast demand for animal protein requirements and consequently in food security. However, environmental contamination and disease prevalence are considered essential challenges for the sector. In this regard, new approaches have been paved in technology to deal effectively with such challenges. Among these, nanotechnology-as a novel and innovative tool-has a broad spectrum of uses and a tremendous potential in aquaculture and seafood preservation. It can provide new technologies for management of drugs as liberation of vaccines and therefore hold the assurance for civilized protection of farmed fish against disease-causing pathogens. This article presents a review of nanotechnology and its applications in aquaculture. Additionally, it gives a brief idea about the fish disease and classical ways of controlling pathogens. On the other hand, this review sheds the light on nanotechnology as a potential novel tool which may possibly enhance the management and the control of disease prevalence. Therefore, the importance of this technology to promote sustainable aquaculture has also been highlighted. Focusing on the role of selenium nanoparticles as an efficient element is discussed also in this article.

Mannose-Modified Liposome Co-Delivery of Human Papillomavirus Type 16 E7 Peptide and CpG Oligodeoxynucleotide Adjuvant Enhances Antitumor Activity Against Established Large TC-1 Grafted Tumors in Mice

Background

Previously, we demonstrated the therapeutic efficacy of a human papillomavirus (HPV) vaccine, including HPV16 E7 peptide and CpG oligodeoxynucleotides (CpG ODN), against small TC-1 grafted tumors. Here, we developed an HPV16 E7 peptide and CpG ODN vaccine delivered using liposomes modified with DC-targeting mannose, Lip E7/CpG, and determined its anti-tumor effects and influence on systemic immune responses and the tumor microenvironment (TME) in a mouse large TC-1 grafted tumor model.

Methods

L-alpha-phosphatidyl choline (SPC), cholesterol (CHOL), 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy (polyethylene glycol-2000)] (DSPE-PEG-2000), 1,2-dioleoyl-3-trimethylammonium-propane chloride salt (DOTAP) and Mannose-PEG-DSPE, loaded with HPV16 E7 peptide and CpG ODN, were used to construct the Lip E7/CpG vaccine. The anti-tumor effects and potential mechanism of Lip E7/CpG were assessed by assays of tumor growth inhibition, immune cells, in vivo cytotoxic T lymphocyte (CTL) responses and cytokines, chemokines, CD31, Ki67 and p53 expression in the TME. In addition, toxicity of Lip E7/CpG to major organs was evaluated.

Results

Lip E7/CpG had a diameter of 122.21±8.37 nm and remained stable at 4°C for 7 days. Co-delivery of HPV16 E7 peptide and CpG ODN by liposomes exerted potent anti-tumor effects in large (tumor volume ≥200mm³) TC-1 grafted tumor-bearing mice with inhibition rates of 80% and 78% relative to the control and Free E7/CpG groups, respectively. Vaccination significantly increased numbers of CD4+ and CD8+ T cells, and IFN-γ-producing cells in spleens and tumors and enhanced HPV-specific CTL responses, while reducing numbers of inhibitory cells including myeloid-derived suppressor cells and macrophages. Expression of cytokines and chemokines was altered and formation of tumor blood vessels was reduced in the Lip E7/CpG group, indicating possible modulation of the immunosuppressive TME to promote anti-tumor responses. Lip E7/CpG did not cause morphological changes in major organs.

Conclusion

Lip E7/CpG induced anti-tumor effects by enhancing cellular immunity and improving tumor-associated immunosuppression. Mannose-modified liposomes are the promising vaccine delivery strategy for cancer immunotherapy.

Leveraging the modularity of biomaterial carriers to tune immune responses

Biomaterial carriers offer modular features to control the delivery and presentation of vaccines and immunotherapies. This tunability is a distinct capability of biomaterials. Understanding how tunable material features impact immune responses is important to improve vaccine and immunotherapy design, as well as clinical translation. Here we discuss the modularity of biomaterial properties as a means of controlling encounters with immune signals across scales - tissue, cell, molecular, and time - and ultimately, to direct stimulation or regulation of immune function. We highlight these advances using illustrations from recent literature across infectious disease, cancer, and autoimmunity. As the immune engineering field matures, informed design criteria could support more rational biomaterial carriers for vaccination and immunotherapy.

Therapeutic Vaccines for Cancer Immunotherapy

The rapid development of nanobiotechnology has enabled progress in therapeutic cancer vaccines. These vaccines stimulate the host innate immune response by tumor antigens followed by a cascading adaptive response against cancer. However, an improved antitumor immune response is still in high demand because of the unsatisfactory clinical performance of the vaccine in tumor inhibition and regression. To date, a complicated tumor immunosuppressive environment and suboptimal design are the main obstacles for therapeutic cancer vaccines. The optimization of tumor antigens, vaccine delivery pathways, and proper adjuvants for innate immune response initiation, along with reprogramming of the tumor immunosuppressive environment, is essential for therapeutic cancer vaccines in triggering an adequate antitumor immune response. In this review, we aim to review the challenges in and strategies for enhancing the efficacy of therapeutic vaccines. We start with the summary of the available tumor antigens and their properties and then the optimal strategies for vaccine delivery. Subsequently, the vaccine adjuvants focused on the intrinsic adjuvant properties of nanostructures are further discussed. Finally, we summarize the combination strategies with therapeutic cancer vaccines and discuss their positive impact in cancer immunity.

Liposome-Based Drug Delivery Systems in Cancer Immunotherapy

Cancer immunotherapy has shown remarkable progress in recent years. Nanocarriers, such as liposomes, have favorable advantages with the potential to further improve cancer immunotherapy and even stronger immune responses by improving cell type-specific delivery and enhancing drug efficacy. Liposomes can offer solutions to common problems faced by several cancer immunotherapies, including the following: (1) Vaccination: Liposomes can improve the delivery of antigens and other stimulatory molecules to antigen-presenting cells or T cells; (2) Tumor normalization: Liposomes can deliver drugs selectively to the tumor microenvironment to overcome the immune-suppressive state; (3) Rewiring of tumor signaling: Liposomes can be used for the delivery of specific drugs to specific cell types to correct or modulate pathways to facilitate better anti-tumor immune responses; (4) Combinational therapy: Liposomes are ideal vehicles for the simultaneous delivery of drugs to be combined with other therapies, including chemotherapy, radiotherapy, and phototherapy. In this review, different liposomal systems specifically developed for immunomodulation in cancer are summarized and discussed.

Nanoparticle cancer vaccines: Design considerations and recent advances

Vaccines therapeutics manipulate host's immune system and have broad potential for cancer prevention and treatment. However, due to poor immunogenicity and limited safety, fewer cancer vaccines have been successful in clinical trials. Over the past decades, nanotechnology has been exploited to deliver cancer vaccines, eliciting long-lasting and effective immune responses. Compared to traditional vaccines, cancer vaccines delivered by nanomaterials can be tuned towards desired immune profiles by (1) optimizing the physicochemical properties of the nanomaterial carriers, (2) modifying the nanomaterials with targeting molecules, or (3) co-encapsulating with immunostimulators. In order to develop vaccines with desired immunogenicity, a thorough understanding of parameters that affect immune responses is required. Herein, we discussed the effects of physicochemical properties on antigen presentation and immune response, including but not limited to size, particle rigidity, intrinsic immunogenicity. Furthermore, we provided a detailed overview of recent preclinical and clinical advances in nanotechnology for cancer vaccines, and considerations for future directions in advancing the vaccine platform to widespread anti-cancer applications.

Lymphatic targeting by albumin-hitchhiking: Applications and optimisation

The lymphatic system plays an integral role in the development and progression of a range of disease conditions, which has impelled medical researchers and clinicians to design, develop and utilize advanced lymphatic drug delivery systems. Following interstitial administration, most therapeutics and molecules are cleared from tissues via the draining blood capillaries. Macromolecules and delivery systems >20 kDa in size or 10-100 nm in diameter are, however, transported from the interstitium via draining lymphatic vessels as they are too large to cross the blood capillary endothelium. Lymphatic uptake of small molecules can be promoted by two general approaches: administration in association with synthetic macromolecular constructs, or through hitchhiking on endogenous cells or macromolecular carriers that are transported from tissues via the lymphatics. In this paper we review the latter approach where molecules are targeted to lymph by hitchhiking on endogenous albumin transport pathways after subcutaneous, intramuscular or intradermal injection. We describe the properties of the lymphatic system and albumin that are relevant to lymphatic targeting, the characteristics of drugs and delivery systems designed to hitchhike on albumin trafficking pathways and how to further optimise these properties, and finally the current applications and potential future directions for albumin-hitchhiking approaches to target the lymphatics.

Gold nanoparticles for preparation of antibodies and vaccines against infectious diseases

INTRODUCTION

Vaccination remains very effective in stimulating protective immune responses against infections. An important task in antibody and vaccine preparation is to choose an optimal carrier that will ensure a high immune response. Particularly promising in this regard are nanoscale particle carriers. An antigen that is adsorbed or encapsulated by nanoparticles can be used as an adjuvant to optimize the immune response during vaccination. a very popular antigen carrier used for immunization and vaccination is gold nanoparticles, with are being used to make new vaccines against viral, bacterial, and parasitic infections.

AREAS COVERED

This review summarizes what is currently known about the use of gold nanoparticles as an antigen carrier and adjuvant to prepare antibodies in vivo and design vaccines against viral, bacterial, and parasitic infections. The basic principles, recent advances, and current problems in the use of gold nanoparticles are discussed.

EXPERT OPINION

Gold nanoparticles can be used as adjuvants to increase the effectiveness of vaccines by stimulating antigen-presenting cells and ensuring controlled antigen release. Studying the characteristics of the immune response obtained from the use of gold nanoparticles as a carrier and an adjuvant will permit the particles' potential for vaccine design to be increased.

Efficacy of chitosan-based nanoparticle vaccine administered to broiler birds challenged with Salmonella

Two experiments were conducted to evaluate the immune response of broilers vaccinated with Salmonella chitosan-nanoparticle (CNP) vaccine and challenged with Salmonella. The Salmonella CNP vaccine was synthesized with Salmonella enterica outer membrane proteins (OMPs) and flagellin proteins. In Experiment I, birds were orally gavaged with PBS or 500, 1000, or 2000μg of CNP vaccine 1 and 7d-of-age. At 14d-of-age, birds were orally challenged with 1 X 10⁵ CFU/bird of live S. Enteritidis (SE). Macrophage-nitrite production 11d-post-challenge was higher (P<0.05) in the 500μg group when compared to the control. At d14 (8h-post-challenge), broilers vaccinated with 1000μg CNP had higher (P<0.05) serum anti-OMPs IgG and IgA and cloacal anti-OMP IgA amounts. At 11d-post-challenge, birds vaccinated with 1000μg CNP vaccine had greater (P<0.05) bile anti-OMP and anti-flagellin IgA amounts. At 11d-post-challenge, birds administered 1000μg CNP vaccine has increased (P<0.05) IL-1β and IL-10 mRNA in cecal tonsils. In Experiment II, birds were orally gavaged with PBS or 1000μg CNP or a live commercial vaccine at 1 and 7d-of-age. At 14d-of-age, birds were orally challenged with 1 X 10⁵ CFU/bird of live SE or S. Heidelberg (SH). Birds vaccinated with CNP showed higher (P<0.05) serum anti-OMPs IgG amounts at 8h-post-challenge. At 4d-post-SH challenge, birds vaccinated with CNP had higher (P<0.05) bile anti-flagellin IgA amounts. CNP decreased (P<0.05) anti-OMPs IgG levels in serum at 2d-post-SE challenge and 4d-post-SH or SE challenge. Salmonella Enteritidis loads in cecal content at 2d-post-challenge was decreased (P<0.05) by 65.9% in birds vaccinated with CNP, when compared to the control. Chitosan-nanovaccine had no adverse effects on bird’s production performance. In conclusion, 1000μg CNP vaccine can induce a specific immune response against Salmonella and has the potential to mitigate SE cecal colonization in broiler birds.

Immunology-Guided Biomaterial Design for Mucosal Cancer Vaccines

Cancer of mucosal tissues is a major cause of worldwide mortality for which only palliative treatments are available for patients with late-stage disease. Engineered cancer vaccines offer a promising approach for inducing antitumor immunity. The route of vaccination plays a major role in dictating the migratory pattern of lymphocytes, and thus vaccine efficacy in mucosal tissues. Parenteral immunization, specifically subcutaneous and intramuscular, is the most common vaccination route. However, this induces marginal mucosal protection in the absence of tissue-specific imprinting signals. To circumvent this, the mucosal route can be utilized, however degradative mucosal barriers must be overcome. Hence, vaccine administration route and selection of materials able to surmount transport barriers are important considerations in mucosal cancer vaccine design. Here, an overview of mucosal immunity in the context of cancer and mucosal cancer clinical trials is provided. Key considerations are described regarding the design of biomaterial-based vaccines that will afford antitumor immune protection at mucosal surfaces, despite limited knowledge surrounding mucosal vaccination, particularly aided by biomaterials and mechanistic immune-material interactions. Finally, an outlook is given of how future biomaterial-based mucosal cancer vaccines will be shaped by new discoveries in mucosal vaccinology, tumor immunology, immuno-therapeutic screens, and material-immune system interplay.

A Novel Transdermal Protein Delivery Strategy via Electrohydrodynamic Coating of PLGA Microparticles onto Microneedles

Transdermal delivery of biological therapeutics is emerging as a potent alternative to intravenous or subcutaneous injections. The latter possess major challenges including patient discomfort, the necessity for trained personnel, specialized sharps disposal, and risk of infection. The microneedle (MN) technology circumvents many of the abovementioned challenges, delivering biological materials directly into the skin and allowing sustained release of the active ingredient both in animal models and in humans. This study describes the use of electrohydrodynamic atomization (EHDA) to coat ovalbumin (OVA)-loaded PLGA nanoparticles onto hydrogel-forming MN arrays. The particles showed extended release of OVA over ca. 28 days. Microscopic analysis demonstrated that EHDA could generate a uniform particle coating on the MNs, with 30% coating efficiency. Furthermore, the coated MN array manifested similar mechanical characteristics and insertion properties to the uncoated system, suggesting that the coating should have no detrimental effects on the application of the MNs. The coated MNs resulted in no significant increase in anti-OVA-specific IgG titres in C57BL/6 mice in vivo as compared to the untreated mice (paired t-test, p > 0.05), indicating that the formulations are nonimmunogenic. The approach of using EHDA to coat an MN array thus appears to have potential as a novel noninvasive protein delivery strategy.

Synergistic anti-tumor efficacy by combination therapy of a self-assembled nanogel vaccine with an immune checkpoint anti-PD-1 antibody

Therapeutic strategies for cancer involving immune checkpoint inhibitors (ICIs) have been gaining widespread attention, but their efficacy remains limited. Thus, combination of ICI therapies with other therapeutic modalities may be required to improve their outcomes. In this study, we examined the improved efficacy of a CHP nanogel-based vaccine delivery system after combination with ICI therapy. For this, we evaluated the therapeutic efficacy of combining an anti-PD-1 antibody as an ICI with an OVA antigen-complexed CHP nanogel vaccine delivery system in a mouse E.G7-OVA tumor model. Mice were subcutaneously inoculated with E.G7-OVA tumor cells on one side of the back, and subcutaneously injected with OVA or the OVA/CHP nanogel vaccine on the other side of the back. Anti-PD-1 antibody was administered at defined intervals. Tumor volume, immune responses, and tumor-infiltrating cells were evaluated. Mice treated with OVA vaccine alone showed weak tumor suppression compared with untreated control mice. Mice receiving combined OVA/CHP nanogel vaccine and anti-PD-1 antibody therapy exhibited strong tumor growth suppression and markedly improved survival, suggesting that PD-1 signaling blockade by the anti-PD-1 antibody enhanced the anti-tumor efficacy of the OVA vaccine. Furthermore, tumor-infiltrating cells and immune responses were increased in the combined therapy group. No serious side effects were observed for any of the treatments. Taken together, the immune system activation induced by the CHP nanogel vaccine was synergistically enhanced by the anti-PD-1 antibody. The present findings suggest the potential for enhanced therapeutic efficacy by combining the CHP nanogel vaccine delivery system with ICI therapy for various cancer types.

Combination therapy of OVA/CHP nanogel vaccine with anti-PD-1 antibody synergistically improved anti-tumor effect and survival rate without side effects.

Development and in vitro evaluation of a new adjuvant system containing Salmonella Typhi porins and chitosan

In order to improve the immunogenicity of the highly purified vaccine antigens, addition of an adjuvant to formulation, without affecting the safety of the vaccine, has been the key aim of the vaccine formulators. In recent years, adjuvants which are composed of a delivery system and immunopotentiators have been preferred to induce potent immune responses. In this study, we have combined Salmonella Typhi porins and chitosan to develop a new adjuvant system to enhance the immunogenicity of the highly purified antigens. Cationic gels, microparticle (1.69 ± 0.01 μm) and nanoparticles (337.7 ± 1.7 nm) based on chitosan were prepared with high loading efficiency of porins. Cellular uptake was examined by confocal laser scanning microscopy, and the macrophage activation was investigated by measuring the surface marker as well as the cytokine release in vitro in J774A.1 macrophage murine cells. Porins alone were not taken up by the macrophage cells whereas in combination with chitosan a significant uptake was obtained. Porins-chitosan combination systems were found to induce CD80, CD86 and MHC-II expressions at different levels by different formulations depending on the particle size. Similarly, TNF-α and IL-6 levels were found to increase with porins-chitosan combination. Our results demonstrated that combination of porins with chitosan as a particulate system exerts enhanced adjuvant effect, suggesting a promising adjuvant system for subunit vaccines with combined immunostimulating activity.

A self-aggregating peptide: implications for the development of thermostable vaccine candidates

BACKGROUND

The use of biomaterials has been expanded to improve the characteristics of vaccines. Recently we have identified that the peptide PH_(1-110) from polyhedrin self-aggregates and incorporates foreign proteins to form particles. We have proposed that this peptide can be used as an antigen carrying system for vaccines. However, the immune response generated by the antigen fused to the peptide has not been fully characterized. In addition, the adjuvant effect and thermostability of the particles has not been evaluated.

RESULTS

In the present study we demonstrate the use of a system developed to generate nano and microparticles carrying as a fusion protein peptides or proteins of interest to be used as vaccines. These particles are purified easily by centrifugation. Immunization of animals with the particles in the absence of adjuvant result in a robust and long-lasting immune response. Proteins contained inside the particles are maintained for over 1 year at ambient temperature, preserving their immunological properties.

CONCLUSION

The rapid and efficient production of the particles in addition to the robust immune response they generate position this system as an excellent method for the rapid response against emerging diseases. The thermostability conferred by the particle system facilitates the distribution of the vaccines in developing countries or areas with no electricity.

Polyacrylate-Peptide Antigen Conjugate as a Single-Dose Oral Vaccine against Group A Streptococcus

Group A Streptococcus (GAS)-associated rheumatic heart disease is a leading cause of death caused by GAS infection. While antibiotics can treat the infection in most cases, growing antibiotic resistance, late medical intervention, and recurrent infection are major obstacles to the effective treatment of GAS-associated diseases. As GAS infection typically originates from the bacterial colonization of mucosal tissue in the throat, an oral vaccine that can generate both systemic and mucosal immune responses would solve problems associated with traditional medical interventions. Moreover, orally delivered vaccines are more easily administered and less expensive for mass immunization. In this study, the B-cell epitope J8, derived from GAS M protein, and universal T-helper Pan HLA-DR-binding epitope peptide (PADRE), were conjugated to poly (methyl acrylate) (PMA) to form a self-assembled nanoparticle vaccine candidate (PMA-P-J8). Strong systemic and mucosal immune responses were induced upon single oral immunization of mice with the conjugate. The antibodies generated were opsonic against GAS clinical isolates as measured after boost immunization. Thus, we developed a simple conjugate as an effective, adjuvant-free oral peptide-based vaccine.

Double-Layered M2e-NA Protein Nanoparticle Immunization Induces Broad Cross-Protection against Different Influenza Viruses in Mice

The development of a universal influenza vaccine is an ideal strategy to eliminate public health threats from influenza epidemics and pandemics. This ultimate goal is restricted by the low immunogenicity of conserved influenza epitopes. Layered protein nanoparticles composed of well-designed conserved influenza structures have shown improved immunogenicity with new physical and biochemical features. Herein, structure-stabilized influenza matrix protein 2 ectodomain (M2e) and M2e-neuraminidase fusion (M2e-NA) recombinant proteins are generated and M2e protein nanoparticles and double-layered M2e-NA protein nanoparticles are produced by ethanol desolvation and chemical crosslinking. Immunizations with these protein nanoparticles induce immune protection against different viruses of homologous and heterosubtypic NA in mice. Double-layered M2e-NA protein nanoparticles induce higher levels of humoral and cellular responses compared with their comprising protein mixture or M2e nanoparticles. Strong cytotoxic T cell responses are induced in the layered M2e-NA protein nanoparticle groups. Antibody responses contribute to the heterosubtypic NA immune protection. The protective immunity is long lasting. These results demonstrate that double-layered protein nanoparticles containing structure-stabilized M2e and NA can be developed into a universal influenza vaccine or a synergistic component of such vaccines. Layered protein nanoparticles can be a general vaccine platform for different pathogens.

An overview of biodegradable nanomaterials and applications in vaccines

Vaccination is the most cost-effective and sustainable way to prevent and eliminate infectious diseases. Compared with traditional vaccines, novel vaccines have better stability, longer duration and require less antigen usage. In addition, novel vaccines have better immune effects and significantly less toxic side effects. However, both novel vaccines and traditional vaccines require carrier molecules or adjuvants to produce an optimal immune response. There is an increasing demand for vaccine adjuvants and delivery systems that can induce stronger immune response whilst reducing production cost and the dose of vaccine. In recent years, nanotechnology has played an important role in the development of novel vaccine adjuvants and nano-delivery systems. Biodegradable materials have also received a lot of attention in medical science because they have excellent biocompatibility, biodegradability and low toxicity, which can protect antigens from degradation, increase antigen stability and provide slow release; resulting in enhanced immunogenicity. Therefore, biodegradable nanoparticles have attracted much attention in the formulation of vaccines. In this review, we outline some key features of biodegradable nanomaterials in the developing safer and more effective vaccines. The properties, structural characteristics, advantages and disadvantage of the biodegradable nanomaterials will be systematically reviewed. Additionally, applications, research progress and future prospects of biodegradable nanomaterials are discussed. This review will be help in future research work directed at developing biodegradable vaccine adjuvants or delivery carriers.

The roles of mesoporous silica and carbon nanoparticles in antigen stability and intensity of immune response against recombinant subunit B of cholera toxin in a rabbit animal model

Vaccines are the front line in the fight against diseases. However, setbacks with existing cholera vaccines have ignited a considerable effort to develop more suitable vaccine formulations. In this study, we aim to investigate the effect of antigen stability and controlled release in inducing an immune response. Therefore, two types of silica and carbon mesoporous nanoparticles of the same size and shape but different pore architectures were synthesized and loaded with recombinant cholera toxin subunit B to serve as a model for antigen stability and controlled release of antigenic CTB. In order to evaluate immune response efficacy for these model formulations, IgG and IgA responses and fluid accumulation (FA) index were measured in immunized rabbits, which were challenged with wild-type Vibrio cholerae. Our result suggests that mesoporous silica nanoparticles have greater efficacy in inducing mucosal immune responses, and it proved more proficiency in overall immune responses in challenge experiments and FA index (p < 0.05). These findings indicate that mesoporous nanoparticles and, in particular, mesoporous silica nanoparticles, could be used in oral vaccine formulation against cholera.