Angelica sinensis polysaccharide encapsulated into PLGA nanoparticles as a vaccine delivery and adjuvant system for ovalbumin to promote immune responses

Plant-Derived Immunomodulatory Nanoadjuvants for Cancer Vaccines: Current Status and Future Opportunities

Cancer is a major cause of death worldwide, and vaccine administration is an effective way to stimulate immune responses in patients and to achieve preventive and therapeutic effects. Few vaccines have been used in clinical settings because they have poor immunogenicity, and it is difficult to induce a robust immune response in patients. An adjuvant is an important component of a vaccine that can enhance the intensity, speed, and duration of immune responses. The achievements of adjuvants in the production of stable, safe, and immunogenic tumor vaccines have aroused the enthusiasm of researchers. Recent results have suggested that plant-derived adjuvants have unique advantages, such as greatly improving immune responses to cancer vaccines and promoting humoral and cellular immunity with good biocompatibility and biodegradability. When these adjuvants are used in combination with vaccines, they can not only activate the immune response in vivo but can also promote cytokine secretion and accelerate dendritic cell maturation. This review focused on the application progress of plant adjuvants, including saponins, polysaccharides, flavonoids, and plant virus-like particles, and their combination with nano-delivery systems in cancer vaccines. At the same time, we have also discussed the immunomodulatory mechanisms of these adjuvants and their prospects for improving vaccine efficacy in the treatment of cancer in the future. These promising plant adjuvants may provide prospects and a research basis for the development of tumor vaccines.

Harnessing phytochemicals: Innovative strategies to enhance cancer immunotherapy

Cancer immunotherapy has revolutionized cancer treatment, but therapeutic ineffectiveness-driven by the tumor microenvironment and immune evasion mechanisms-continues to limit its clinical efficacy. This challenge underscores the need to explore innovative approaches, such as multimodal immunotherapy. Phytochemicals, bioactive compounds derived from plants, have emerged as promising candidates for overcoming these barriers due to their immunomodulatory and antitumor properties. This review explores the synergistic potential of phytochemicals in enhancing immunotherapy by modulating immune responses, reprogramming the tumor microenvironment, and reducing immunosuppressive factors. Integrating phytochemicals with conventional immunotherapy strategies represents a novel approach to mitigating resistance and enhancing therapeutic outcomes. For instance, nab-paclitaxel has shown the potential in overcoming resistance to immune checkpoint inhibitors, while QS-21 synergistically enhances the efficacy of tumor vaccines. Furthermore, we highlight recent advancements in leveraging nanotechnology to engineer phytochemicals for improved bioavailability and targeted delivery. These innovations hold great promise for optimizing the clinical application of phytochemicals. However, further large-scale clinical studies are crucial to fully integrate these compounds into immunotherapeutic regimens effectively.

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.

Poria cocos polysaccharide-loaded Alum Pickering emulsion as vaccine adjuvant to enhance immune responses

Traditional Alum adjuvants mainly elicit a Th2 humoral immune response, but fail to generate a robust Th1 cellular immune response. However, the cellular immune response is essential for vaccination against cancer and a number of chronic infectious diseases, including human immunodeficiency virus infection and tuberculosis. In our previous study, we demonstrated that the polysaccharide from Poria cocos (PCP) has the potential to serve as an immunologic stimulant, enhancing both humoral and cellular immune responses. However, this effect was only observed at high concentrations. In this study, to enhance the immune-stimulation effect of PCP and modify the type of immune response elicited by Alum adjuvant, we successfully developed a Pickering emulsion delivery system (PCP-Al-Pickering) using PCP-loaded Alhydrogel particles as the stabilizer. After optimization, the Pickering emulsion exhibited excellent storage capacity and effectively adsorbed the PCP and antigen. As an adjuvant delivery system, the PCP-Al-Pickering emulsion facilitated the antigen uptake by macrophages, increased the recruitment of cells at injection sites, improved the activation of dendritic cells in draining lymph nodes, elicited a potent and durable antibody response, and promoted the activation of CD4+ and CD8+ T cells. Importantly, the PCP-Al-Pickering emulsion adjuvant elicited a balanced Th1 and Th2 immune response, in comparison to Alum adjuvant. The PCP-Al-Pickering emulsion may serve as a safe and promising adjuvant delivery system to enhance immune responses.

Advancements in Nanoparticle-Based Adjuvants for Enhanced Tuberculosis Vaccination: A Review

Tuberculosis (TB) remains a leading cause of morbidity and mortality worldwide, necessitating the development of more effective vaccines. Nanoparticle-based adjuvants represent a promising approach to enhancing tuberculosis vaccine efficacy. This review focuses on the advantages of nanoparticulate-loaded vaccines, emphasizing their ability to improve antigen delivery, safety, and immunogenicity. We discuss the various types of nanoparticles and their unique physicochemical properties that contribute to improved antigen delivery and sustained immune activation. Additionally, we highlight the advantages of nanoparticle-based adjuvants in inducing strong cellular and humoral immunity, enhancing vaccine stability, and reducing adverse effects. Finally, we address current challenges and future perspectives in the application of these novel adjuvants, emphasizing their potential to transform TB vaccine strategies and ultimately contribute to better global health outcomes.

Immune enhancement of rhamnolipid/manganese calcium phosphate mineralized nanoparticle: A promising subunit antigen delivery system

The use of biomimetic mineralization strategy is promising to solve the problem of poor stability and immune effect of subunit antigens. However, non-specifically inducing protein mineralization is still a challenge. we hypothesized that rhamnolipids with both protein and metal binding capacity could be used to develop more functional and biocompatible calcium mineralized nanoparticle (RMCP). The results show that rhamnolipids synergistically enhanced the mineralization of protein with manganese ions and improved 21 % the loading antigens of RMCP compared to manganese calcium phosphate nanoparticles. Transmission electron microscopy (TEM) and Dynamic Light Scattering (DLS) showed particle size of RMCP is 260 ± 12.1 nm with spherical morphology. In vitro experiments have shown that RMCP effectively activate immune cells through the cGAS-STING and NLRP3 pathways and demonstrated a higher level of cytokines in RAW264.7 Macrophages. In vivo, RMCP triggered an increased IgG titer with 16.5-fold IgG2a/IgG1 ratio compared to the aluminum adjuvant which improved the recovery status after challenge in mice. We used biological surfactants for the first time to enhance the biomimetic mineralization process of subunit antigen, which provides a new approach for constructing calcium-based biocompatible antigen delivery vectors, helping to develop a new generation of stable, efficient, and safe subunit vaccines.

Chinese yam polysaccharide-loaded aluminium hydroxide nanoparticles used as vaccine adjuvant to induce potent humoral and cellular immune responses

Due to their safety and efficacy, aluminium salts (Alum) are considered the most important adjuvants in human vaccines. However, Alum adjuvants are unable to elicit a cellular immune response, which is vital for the prevention of various chronic infectious diseases and cancers. Herein, we isolated and purified a water-soluble polysaccharide from Chinese yam, named CYP, which was primarily composed of →4)-α-D-Glcp-(1→, →4,6)-α-D-Glcp-(1→, and α-D-Glcp-(1→. Meanwhile, we prepared aluminium hydroxide nanoparticles (Al NPs) with a nanometer-scale size and thin stick-like shape. Being an immunostimulant, the CYP was then loaded onto the Al NPs to obtain a novel adjuvant delivery system (CYP-Al NPs) that enhances the immunostimulatory activity of CYP. Our findings showed that the CYP-Al NPs facilitated macrophages activation and promoted the antigen uptake by macrophages. The in vivo experiment showed that the CYP-Al NPs, as the adjuvant to ovalbumin, promoted the activation of dendritic cells and germinal center B cells in draining lymph nodes, induced a durable and strong antibody response, especially the Th1-type IgG2a antibody response, and improved the cytotoxic T lymphocytes response. These results demonstrated that the CYP-Al NPs could generate robust humoral and cellular responses, and has the great potential to serve as an adjuvant delivery system.

Surface-Engineered Polygonatum Sibiricum Polysaccharide CaCO3 Microparticles as Novel Vaccine Adjuvants to Enhance Immune Response

Micro- and nanoparticles delivery systems have been widely studied as vaccine adjuvants to enhance immunogenicity and sustain long-term immune responses. Polygonatum sibiricum polysaccharide (PSP) has been widely studied as an immunoregulator in improving immune responses. In this study, we synthesized and characterized cationic modified calcium carbonate (CaCO3) microparticles loaded with PSP (PEI-PSP-CaCO3, CTAB-PSP-CaCO3), studied the immune responses elicited by PEI-PSP-CaCO3 and CTAB-PSP-CaCO3 carrying ovalbumin (OVA). Our results demonstrated that PEI-PSP-CaCO3 significantly enhanced the secretion of IgG and cytokines (IL-4, IL-6, IFN-γ, and TNF-α) in vaccinated mice. Additionally, PEI-PSP-CaCO3 induced the activation of dendritic cells (DCs), T cells, and germinal center (GC) B cells in draining lymph nodes (dLNs). It also enhanced lymphocyte proliferation, increased the ratio of CD4+/CD8+ T cells, and elevated the frequency of CD3+ CD69+ T cells in spleen lymphocytes. Therefore, PEI-PSP-CaCO3 microparticles induced a stronger cellular and humoral immune response and could be potentially useful as a vaccine delivery and adjuvant system.

pH-responsive self-assembled nanoparticles for tumor-targeted drug delivery

Recent advances in the field of drug delivery have opened new avenues for the development of novel nanodrug delivery systems (NDDS) in cancer therapy. Self-assembled nanoparticles (SANPs) based on tumour microenvironment have great advantages in improving antitumor effect, and pH-responsive SANPs prepared by the combination of pH-responsive nanomaterials and self-assembly technology can effectively improve the efficacy and reduce the systemic toxicity of antitumor drugs. In this review, we describe the characteristics of self-assembly and its driving force, the mechanism of pH-responsive NDDS, and the nanomaterials for pH-responsive SANPs type. A series of pH-responsive SANPs for tumour-targeted drug delivery are discussed, with an emphasis on the relation between structural features and theranostic performance.

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.

Preparation and adjuvanticity against PCV2 of Viola philippica polysaccharide loaded in Chitosan-Gold nanoparticle

The present Porcine circovirus type 2 virus (PCV2) vaccine adjuvants suffer from numerous limitations, such as adverse effects, deficient cell-mediated immune responses, and inadequate antibody production. In this study, we explored the potential of a novel nanoparticle (CS-Au NPs) based on gold nanoparticles (Au NPs) and chitosan (CS) that modified Viola philippica polysaccharide (VPP) as efficient adjuvants for PCV2 vaccine. The characterization demonstrated that CS-Au-VPP NPs had a mean particle size of 507.42 nm and a zeta potential value of -21.93 mV. CS-Au-VPP NPs also exhibited good dispersion and a stable structure, which did not alter the polysaccharide properties. Additionally, the CS-Au-VPP NPs showed easy absorption and utilization by the organism. To investigate their immune-enhancing potential, mice were immunized with a mixture of CS-Au-VPP NPs and PCV2 vaccine. The evaluation of relevant immunological indicators, including specific IgG antibodies and their subclasses, cytokines, and T cell subpopulations, confirmed their immune-boosting effects. The in vivo experiments revealed that the medium-dose CS-Au-VPP NPs significantly elevated the levels of specific IgG antibodies and their subclasses, cytokines, and T cell subpopulations in PCV2-immunized mice. These findings suggest that CS-Au-VPP NPs can serve as a promising vaccine adjuvant due to their stable structure and immunoenhancement capabilities.

Cistanche deserticola polysaccharide-functionalized dendritic fibrous nano-silica as oral vaccine adjuvant delivery enhancing both the mucosal and systemic immunity

Oral vaccines are a safe and convenient alternative to injected vaccines and have great potential to prevent major infectious diseases. However, the harsh gastrointestinal (GI) environment, mucus barriers, low immunogenicity, and lack of effective and safe mucosal adjuvants are the major challenges for oral vaccine delivery. In recent years, nanoparticle-based strategies have become attractive for improving oral vaccine delivery. Here, the dendritic fibrous nano-silica (DFNS) grafted with Cistanche deserticola polysaccharide (CDP) nanoparticles (CDP-DFNS) were prepared and investigated how to impact the immune responses. CDP-DFNS facilitated the antigen uptake in mouse bone marrow-derived dendritic cells (BMDCs), and induce the activation of DCs in vitro. Furthermore, in vivo experiments, the result showed that the uptake efficiency by Peyer's patches (PPs) of CDP-DFNS/BSA was the best. And CDP-DFNS/BSA then significantly activated the DCs in lamina propria (LP), and T/B cells in PPs and mesenteric lymph nodes (MLNs). Moreover, the memory T cell responses in later period of vaccination was stronger than other groups. In addition, CDP-DFNS/BSA enhanced BSA-specific antibody IgG, IgA production, and SIgA secretion, was effective at inducing a strong mixed Th1/Th2 response and mucosal antibody responses. These results indicated that CDP-DFNS deserves further consideration as an oral vaccine adjuvant delivery system.

Preparation, characterization and immune response of chitosan‑gold loaded Myricaria germanica polysaccharide

In this study, a novel nano-drug delivery system (CS-Au NPs) based on gold nanoparticles (Au NPs) and chitosan (CS) that modified Myricaria germanica polysaccharide (MGP) was developed to enhance immune responses. At a MGP to CS Au ratio of 5:1, CS-Au-MGP NPs had a loading capacity of 78.27 %. The structure of CS-Au-MGP NPs were characterized by Transmission electron microscope, TEM-energy dispersive spectroscopy mapping, Fourier transform infrared spectroscopy, X-ray photoelectron spectrometer, particle size and zeta-potential distribution analysis. Under weakly acidic conditions, in vitro CS-Au-MGP NPs release was most effective. In vivo showed that co-immunization with CS-Au-MGP NPs and PCV2 significantly increased the organ index of the thymus, spleen, and liver in mice. Additionally, CS-Au-MGP NPs significantly increased the levels of IgG, IgG1, and IgG2a antibodies, as well as IFN-γ and IL-6 levels. Furthermore, the CS-Au-MGP NPs promoted proliferation of spleen T and B lymphocytes, increased the number of CD3+, CD4+, and CD8+ cells, and increased the CD4+/CD8+ T cell ratio. Meanwhile, CS-Au-MGP NPs remarkably TLR2/IRAK4 pathway activation and mRNA levels of cytokines (IFN-γ and IL-6). These results indicated that CS-Au-MGP NPs could enhance the immune activity, and it could be potentially used as an MGP delivery system for the induction of strong immune responses.

Potential of DPD ((S)-4,5-dihydroxy-2,3-pentanedione) Analogs in Microparticulate Formulation as Vaccine Adjuvants

The molecule (S)-4,5-dihydroxy-2,3-pentanedione (DPD) is produced by many different species of bacteria and is involved in bacterial communication. DPD is the precursor of signal molecule autoinducer-2 (AI-2) and has high potential to be used as a vaccine adjuvant. Vaccine adjuvants are compounds that enhance the stability and immunogenicity of vaccine antigens, modulate efficacy, and increase the immune response to a particular antigen. Previously, the microparticulate form of (S)-DPD was found to have an adjuvant effect with the gonorrhea vaccine. In this study, we evaluated the immunogenicity and adjuvanticity of several synthetic analogs of the (S)-DPD molecule, including ent-DPD((R)-4,5-dihydroxy-2,3-pentanedione), n-butyl-DPD ((S)-1,2-dihydroxy-3,4-octanedione), isobutyl-DPD ((S)-1,2-dihydroxy-6-methyl-3,4-heptanedione), n-hexyl-DPD ((S)-1,2-dihydroxy-3,4-decanedione), and phenyl-DPD ((S)-3,4-dihydroxy-1-phenyl-1,2-butanedione), in microparticulate formulations. The microparticulate formulations of all analogs of (S)-DPD were found to be noncytotoxic toward dendritic cells. Among these analogs, ent-DPD, n-butyl-DPD, and isobutyl-DPD were found to be immunogenic toward antigens and showed adjuvant efficacy with microparticulate gonorrhea vaccines. It was observed that n-hexyl-DPD and phenyl-DPD did not show any adjuvant effect. This study shows that synthetic analogs of (S)-DPD molecules are capable of eliciting adjuvant effects with vaccines. A future in vivo evaluation will further confirm that these analogs are promising vaccine adjuvants.

Lentinan-functionalized graphene oxide hydrogel as a sustained antigen delivery system for vaccines

Hydrogel has been proven to have the ability to deliver antigens continuously to achieve slow vaccine delivery, which makes it a promising candidate for an adjuvant delivery platform. Meanwhile, graphene oxide (GO) has garnered significant attention due to its good biosafety, excellent surface area and easy modification. However, GO exists as weak colloidal particles and poses challenges in self-assembling into a hydrogel structure. Here, we propose an innovative strategy involving self-assembling lentinan-functionalized graphene oxide hydrogel ((LNT-GO Gel) by simply mixing lentinan (LNT)-functionalized GO with polyethylene imide (PEI), which can simultaneously encapsulate antigens, achieve long-lasting release of antigens and generate excellent adjuvant activity. The results indicated that the LNT-GO Gel can control the release of OVA at the injection site and confer targeted delivering capacity to lymph nodes. And the date demonstrates that LNT-GO Gel displays favorable safety and biodegradability in vivo. Moreover, LNT-GO Gel can enhance the activation and maturation of dendritic cells (DCs) in lymph node, induce stronger OVA-specific antibody response, and promote spleen T lymphocyte differentiation, which underscores that LNT-GO Gel has ability to generate stronger antigen-specific humoral and cellular immune responses. Collectively, these results demonstrate the adjuvant potential of the lentinan-functionalized graphene oxide hydrogel (LNT-GO Gel) for subunit vaccine.

Nanotechnology Platform for Advancing Vaccine Development against the COVID-19 Virus

The COVID-19 pandemic has had a profound impact on societies, public health, healthcare systems, and the world economy. With over 771 million people infected worldwide and a staggering death toll exceeding 6,960,783 as of 4 October 2023 (according to the World Health Organization), the urgency for a solution was paramount. Since the outbreak, the demand for immediate treatment for COVID-19 viral infection, as well as for effective vaccination against this virus, was soaring, which led scientists, pharmaceutical/biotech companies, government health agencies, etc., to think about a treatment strategy that could control and minimize this outbreak as soon as possible. Vaccination emerged as the most effective strategy to combat this infectious disease. For vaccination strategies, any conventional vaccine approach using attenuated live or inactivated/engineered virus, as well as other approaches, typically requires years of research and assessment. However, the urgency of the situation promoted a faster and more effective approach to vaccine development against COVID-19. The role of nanotechnology in designing, manufacturing, boosting, and delivering vaccines to the host to counter this virus was unquestionably valued and assessed. Several nanoformulations are discussed here in terms of their composition, physical properties, credibility, and applications in past vaccine development (as well as the possibility of using those used in previous applications for the generation of the COVID-19 vaccine). Controlling and eliminating the spread of the virus and preventing future recurrence requires a safe, tolerable, and effective vaccine strategy. In this review, we discuss the potential of nanoformulations as the basis for an effective vaccine strategy against COVID-19.

Peptide-Based Vaccine against Breast Cancer: Recent Advances and Prospects

Breast cancer is considered the second-leading cancer after lung cancer and is the most prevalent cancer among women globally. Currently, cancer immunotherapy via vaccine has gained great attention due to specific and targeted immune cell activity that creates a potent immune response, thus providing long-lasting protection against the disease. Despite peptides being very susceptible to enzymatic degradation and poor immunogenicity, they can be easily customized with selected epitopes to induce a specific immune response and particulate with carriers to improve their delivery and thus overcome their weaknesses. With advances in nanotechnology, the peptide-based vaccine could incorporate other components, thereby modulating the immune system response against breast cancer. Considering that peptide-based vaccines seem to show remarkably promising outcomes against cancer, this review focuses on and provides a specific view of peptide-based vaccines used against breast cancer. Here, we discuss the benefits associated with a peptide-based vaccine, which can be a mainstay in the prevention and recurrence of breast cancer. Additionally, we also report the results of recent trials as well as plausible prospects for nanotechnology against breast cancer.

Cationic Nanoparticle-Stabilized Vaccine Delivery System for the H9N2 Vaccine to Promote Immune Response in Chickens

Chinese yam polysaccharides (CYPs) have received wide attention for their immunomodulatory activity. Our previous studies had discovered that the Chinese yam polysaccharide PLGA-stabilized Pickering emulsion (CYP-PPAS) can serve as an efficient adjuvant to trigger powerful humoral and cellular immunity. Recently, positively charged nano-adjuvants are easily taken up by antigen-presenting cells, potentially resulting in lysosomal escape, the promotion of antigen cross-presentation, and the induction of CD8 T-cell response. However, reports on the practical application of cationic Pickering emulsions as adjuvants are very limited. Considering the economic damage and public-health risks caused by the H9N2 influenza virus, it is urgent to develop an effective adjuvant for boosting humoral and cellular immunity against influenza virus infection. Here, we applied polyethyleneimine-modified Chinese yam polysaccharide PLGA nanoparticles as particle stabilizers and squalene as the oil core to fabricate a positively charged nanoparticle-stabilized Pickering emulsion adjuvant system (PEI-CYP-PPAS). The cationic Pickering emulsion of PEI-CYP-PPAS was utilized as an adjuvant for the H9N2 Avian influenza vaccine, and the adjuvant activity was compared with the Pickering emulsion of CYP-PPAS and the commercial adjuvant (aluminum adjuvant). The PEI-CYP-PPAS, with a size of about 1164.66 nm and a ζ potential of 33.23 mV, could increase the H9N2 antigen loading efficiency by 83.99%. After vaccination with Pickering emulsions based on H9N2 vaccines, PEI-CYP-PPAS generated higher HI titers and stronger IgG antibodies than CYP-PPAS and Alum and increased the immune organ index of the spleen and bursa of Fabricius without immune organ injury. Moreover, treatment with PEI-CYP-PPAS/H9N2 induced CD4⁺ and CD8⁺ T-cell activation, a high lymphocyte proliferation index, and increased cytokine expression of IL-4, IL-6, and IFN-γ. Thus, compared with the CYP-PPAS and aluminum adjuvant, the cationic nanoparticle-stabilized vaccine delivery system of PEI-CYP-PPAS was an effective adjuvant for H9N2 vaccination to elicit powerful humoral and cellular immune responses.

Cancer Cell Membrane-Coated Gambogic Acid Nanoparticles for Effective Anticancer Vaccination by Activating Dendritic Cells

Purpose

Recent studies have shown that traditional Chinese medicine (TCM), such as gambogic acid (GA), is involved in the regulation of tumor immune microenvironment and can be combined with other anti-tumor treatment strategies. Here, we used GA as an adjuvant to construct a nano-vaccine to improve the anti-tumor immune response of colorectal cancer (CRC).

Materials and Methods

We used a previously reported two-step emulsification method to obtain poly (lactic-co-glycolic acid) /GA nanoparticles (PLGA/GA NPs), and then CT26 colon cancer cell membrane (CCM) was used to obtain CCM-PLGA/GA NPs. This novel nano-vaccine, CCM-PLGA/GA NPs, was co-synthesized with GA as an adjuvant and neoantigen provided by CT26 CCM. We further confirmed the stability, tumor targeting, and cytotoxicity of CCM-PLGA/GA NPs. The regulatory effect on the tumor immune microenvironment, the anti-tumor efficacy, and the combined anti-tumor efficacy with anti-PD-1 monoclonal Antibodies (mAbs) of this novel nano-vaccine was also detected in vivo.

Results

We successfully constructed the CCM-PLGA/GA NPs. In vitro and in vivo tests showed low biological toxicity, as well as the high tumor-targeting ability of the CCM-PLGA/GA NPs. Besides, we revealed a remarkable effect of CCM-PLGA/GA NPs to activate the maturation of dendritic cells (DCs) and the formation of a positive anti-tumor immune microenvironment.

Conclusion

This novel nano-vaccine constructed with GA as the adjuvant and CCM providing the tumor antigen can not only directly kill tumors by enhancing the ability of GA to target tumors, but also indirectly kill tumors by regulating tumor immune microenvironment, providing a new strategy for immunotherapy of CRC.

Metabolites of medicine food homology-derived endophytic fungi and their activities

Medicine food homology (MFH) substances not only provide essential nutrients as food but also have corresponding factors that can prevent and help treat nutritional imbalances, chronic disease, and other related issues. Endophytic fungi associated with plants have potential for use in drug discovery and food therapy. However, the endophytic fungal metabolites from MFH plants and their effects have been overlooked. Therefore, this review focuses on the various biological activities of 108 new metabolites isolated from 53 MFH-derived endophytic fungi. The paper explores the potential nutritional and medicinal value of metabolites of MFH-derived endophytic fungi for food and medical applications. This research is important for the future development of effective, safe, and nontoxic therapeutic nutraceuticals for the prevention and treatment of human diseases.

Herb Polysaccharide-Based Drug Delivery System: Fabrication, Properties, and Applications for Immunotherapy

Herb polysaccharides (HPS) have been studied extensively for their healthcare applications. Though the toxicity was not fully clarified, HPS were widely accepted for their biodegradability and biocompatibility. In addition, as carbohydrate polymers with a unique chemical composition, molecular weight, and functional group profile, HPS can be conjugated, cross-linked, and functionally modified. Thus, they are great candidates for the fabrication of drug delivery systems (DDS). HPS-based DDS (HPS-DDS) can bypass phagocytosis by the reticuloendothelial system, prevent the degradation of biomolecules, and increase the bioavailability of small molecules, thus exerting therapeutic effects. In this review, we focus on the application of HPS as components of immunoregulatory DDS. We summarize the principles governing the fabrication of HPS-DDS, including nanoparticles, micelles, liposomes, microemulsions, hydrogels, and microneedles. In addition, we discuss the role of HPS in DDS for immunotherapy. This comprehensive review provides valuable insights that could guide the design of effective HPS-DDS.

Chinese yam polysaccharides PLGA-stabilized Pickering emulsion as an adjuvant system for PCV- 2 vaccine to enhance immune response

Chinese yam polysaccharides (CYP) exhibit superior adjuvant activity and modulate the immune response, but the low bioavailability limits their clinical application. Pickering emulsions have been proven as an efficient vaccine delivery system to enhance the immune response. Here, we used the Chinese yam polysaccharides PLGA-stabilized Pickering emulsion adjuvant system (CYP-PPAS) loaded with Porcine circovirus 2 as a vaccine and focused on investigating its adjuvant activity on humoral and cellular immunity in mice. The CYP-PPAS increased PCV-2 antigen loading efficiency and showed a high antigen uptake efficiency by macrophages in vitro. In vivo, CYP-PPAS significantly facilitated DCs maturation in draining lymph nodes than CYP or PPAS alone group. The CYP-PPAS also induced an increased proliferation index and a CD4⁺/CD8⁺ ratio. Meanwhile, in contrast to the CYP and PPAS groups, CYP-PPAS elicited a stronger anti-PCV-2 IgG and mixed Th1/Th2 immune response. Specifically, the CYP-PPAS group displayed the high expression of CD107a, FasL, and Granzyme B secretion to augment a strong cytotoxic lymphocyte response. Overall, the CYP-PPAS was a successful adjuvant system for promoting humoral and cellular immune responses, which opens up an avenue for the development of effective adjuvants against infectious diseases.

Preparation and sulfate modified of Lagenaria siceraria (Molina) Standl polysaccharide and its immune-enhancing adjuvant activity

Herbal polysaccharides and their modifiers used as vaccine adjuvants have been widely investigated due to their safety and good immunoenhancing activity. In this study, the 50% ethanol concentration precipitated Lagenaria siceraria(Molina) standl polysaccharide (LSP50) and sulfated modified LSP50 (sLSP50) was prepared, and their characterization was investigated. LSP50 and sLSP50_-1.5 were used as vaccine adjuvants to immunize chickens, and the strength and type of immune responses induced by different adjuvants were detected. Our results showed that LSP50 was homogeneous polysaccharides, and the carbohydrate content was 98.6%. The sLSP50_-1.5 with the DS value of 1.5 was optimized by response surface methodology. The sLSP50_-1.5 has both characteristics of polysaccharide functional groups and sulfate functional groups. Adjuvant activity of LSP50 and sLSP50_-1.5 showed that LSP50 and sLSP50_-1.5 could induce long-lasting and high hemagglutination (HI) titers, antigen-specific lgG-NDV antibody, splenic lymphocyte proliferation, high immune organ index. Moreover, chicken immunized with sLSP50_-1.5 showed a strong mixed Th1-type (IFN-γ and TNF-α) and Th2-type (IL-4 and IL-6) cytokines expression. Thus, these findings demonstrated that sLSP50_-1.5 as a vaccine adjuvant can induce a mixed cellular and humoral immune response and can potentially serve as an effective vaccine adjuvant for NDV antigen.

Emerging role of natural products in cancer immunotherapy

Cancer immunotherapy has become a new generation of anti-tumor treatment, but its indications still focus on several types of tumors that are sensitive to the immune system. Therefore, effective strategies that can expand its indications and enhance its efficiency become the key element for the further development of cancer immunotherapy. Natural products are reported to have this effect on cancer immunotherapy, including cancer vaccines, immune-check points inhibitors, and adoptive immune-cells therapy. And the mechanism of that is mainly attributed to the remodeling of the tumor-immunosuppressive microenvironment, which is the key factor that assists tumor to avoid the recognition and attack from immune system and cancer immunotherapy. Therefore, this review summarizes and concludes the natural products that reportedly improve cancer immunotherapy and investigates the mechanism. And we found that saponins, polysaccharides, and flavonoids are mainly three categories of natural products, which reflected significant effects combined with cancer immunotherapy through reversing the tumor-immunosuppressive microenvironment. Besides, this review also collected the studies about nano-technology used to improve the disadvantages of natural products. All of these studies showed the great potential of natural products in cancer immunotherapy.

Polysaccharides derived from Chinese medicinal herbs: A promising choice of vaccine adjuvants

Adjuvants have been used in vaccines for a long time to promote the body's immune response, reducing vaccine dosage and production costs. Although many vaccine adjuvants are developed, the use in human vaccines is limited because of either limited action or side effects. Therefore, the development of new vaccine adjuvants is required. Many studies have found that natural polysaccharides derived from Traditional Chinese medicine (TCM) possess good immune promoting effects and simultaneously improve humoral, cellular and mucosal immunity. Recently polysaccharide adjuvants have attracted much attention in vaccine preparation because of their intrinsic characteristics: immunomodulation, biocompatibility, biodegradability, low toxicity and safety. This review article systematically analysed the literature on polysaccharides possessing vaccine adjuvant activity from TCM plants, such as Astragalus polysaccharide (APS), Rehmannia glutinosa polysaccharide (RGP), Isatis indigotica root polysaccharides (IRPS), etc. and their derivatives. We believe that polysaccharide adjuvants can be used to prepare the vaccines for clinical use provided their mechanisms of action are studied in detail.

Alhagi honey polysaccharides encapsulated into PLGA nanoparticle-based pickering emulsion as a novel adjuvant to induce strong and long-lasting immune responses

Alhagi honey polysaccharides, extracted from a perennial plant Alhagi pseudalhagi syn, possessed many biological activities such as immune enhancement, anti-tumor effect, and antioxygenation. In this study, we used Alhagi honey polysaccharide encapsulated (poly lactic-co-glycolic acid) (PLGA) nanoparticles to prepare an assembled particles-oil pickering emulsion: PPAS and PEI-PPAS. We investigated the characterization of two pickering emulsions, and the possible mechanism to enhance immune responses. The results showed that PPAS and PEI-PPAS both could load high adsorption of OVA and had ability to sustained controlled release OVA. In vivo experiment, PEI-PPAS/OVA enhanced the levels of IgG and cytokines. Meanwhile, it could effectively target dendritic cells (DCs), promoted the cellular uptake of OVA then activated DCs in lymph nodes. And this effect of PEI-PPAS might be induced through the MHC II and MHC I pathway in DCs. Thus, these findings demonstrated that PEI-PPAS could induce a strong and long-term cellular and humoral immune response, and have potential to applied to vaccine adjuvant delivery system.

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.

LDH nanoparticle adjuvant subunit vaccine induces an effective immune response for porcine epidemic diarrhea virus

Porcine Epidemic Diarrhea (PED) is a highly contagious intestinal disease which mostly caused by Porcine Epidemic Diarrhea Virus (PEDV). The PED has caused huge economic losses to the pig industry all over the world and a valid PEDV vaccine is needed to prevent the infection. In this study, we constructed expression plasmid based on the spike (S) gene of the epidemic PEDV strain. The recombinant eukaryotic S (Se) and prokaryotic S (Sp) subunit proteins were expressed and purified as vaccine antigens. We designed a new subunit vaccine based on S proteins, adjuvanted with layered double hydroxide (LDH). The results indicated that the LDH adjuvanted subunit vaccines induced a better immune effect in terms of antibody level and cellular immune response. In conclusion, this study showed a new design of a PEDV subunit vaccine with nanotechnology and demonstrated the potential for its clinical application.

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

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

Spiky titanium dioxide nanoparticles-loaded Plantaginis Semen polysaccharide as an adjuvant to enhance immune responses

The purpose of this study was to prepare spiky titanium dioxide nanoparticles-loaded Plantaginis Semen polysaccharide (SN-TiO₂-PSP), and the structural characterization and immune response of infectious laryngotracheitis (ILT) vaccine in Hetian chickens were investigated. The structural characterization of SN-TiO₂-PSP was analyzed by FT-IR, TEM, and TGA analysis. And the immune organs indexes, lymphocytes proliferation, specific antibody levels, and ratios of CD4⁺ and CD8⁺ T lymphocytes were studied. Structural characterization results showed that SN-TiO₂-PSP has a typical polysaccharide absorption peak and good stability. The SN-TiO₂-PSP's shape was similar to sea urchin, and its zeta potential and particle size were 27.56 mV and 976.11 nm, respectively. In vivo results showed that SN-TiO₂-PSP could enhance the proliferation of peripheral lymphocytes, specific antibody levels, CD4⁺ and CD8⁺ T lymphocytes ratios, IL-4 and INF-γ levels in Hetian chickens vaccinated with ILT vaccine on D₇, D₁₄, D₂₁, and D₂₈. In addition, SN-TiO₂-PSP not only enhanced the indexes of immune organs but also promoted the development of immune organs. Therefore, SN-TiO₂-PSP has immune adjuvant activity and may become a new potential immune adjuvant.

Mannosylated polylactic-co-glycolic acid (MN-PLGA) nanoparticles induce potent anti-tumor immunity in murine model of breast cancer

Nanoparticle-based cancer immunotherapy is considered a novel and promising therapeutic strategy aimed at stimulating host immune responses against tumors. To this end, in the present study, mannan-decorated polylactic-co-glycolic acid (PLGA) nanoparticles containing tumor cell lysate (TCL) and poly riboinosinic polycytidylic acid (poly I:C) were used as antigen delivery systems to immunize breast tumor-bearing Balb/c mice. PLGA nanoparticles were fabricated employing a double emulsion solvent evaporation method. The formation of spherical and uniform nanoparticles (NPs) ranging 150-250 nm was detected by field emission scanning electron microscopy (FESEM) and dynamic light scattering (DLS). Four nanoformulation were used to treat mice and vaccination-induced immunological responses. Tumor regression and overall survival rate were evaluated in four experimental groups. Tumor cell lysate and poly I:C loaded mannan-decorated nanoparticles (TCL-Poly I:C) NP-MN caused a significant decrease in tumor growth and 2- to 3-fold improvement in survival times of the treated mice. The NPs with or without mannan decoration elicited stronger responses in terms of lymphocyte proliferation, delayed-type hypersensitivity and CD107a expression. Moreover, our data indicated that the production of IFN-γ and IL-2 increased while the production of IL-4 and IL-10 decreased in splenocytes culture supernatants. In the pathological evaluations, we found that necrosis and immune cells infiltration rate in the tumor tissue of the treated mice was elevated, while tumor cellularity and lung metastases significantly decreased in particular in the group that received (TCL-Poly I:C) NP-MN. Altogether, our findings suggested that the mannan-decorated PLGA NPs antigen delivery system had significant anti-tumor effects against the murine model of breast cancer and it could be considered as a step forward to human breast cancer immunotherapy.

Self-assembled aggregations in Coptidis Rhizoma decoction dynamically regulate intestinal tissue permeability through Peyer's patch-associated immunity

Objective

To investigate the dynamic regulation of self-assembled aggregations (SAA) in Coptidis Rhizoma decoction on the permeability of intestinal tissue and the mechanism underlying.

Methods

The effects of SAA on berberine (Ber) absorption were respectively analyzed in an in situ intestinal perfusion model and in an Ussing Chamber jejunum model with or without Peyer's patches (PPs). The expression levels of ZO-1, Occludin and Claudin-1 were detected by immunofluorescence to evaluate the tight junction (TJ) between intestinal epithelium cells. The expression levels of T-box-containing protein expressed in T cells, signal transducers and activators of tranion-6, retinoic acid receptor-related orphan receptor γt and forkhead box P3 in PPs were detected by the reverse transcription-polymerase chain reaction and the secretions of interferon-γ (IFN-γ), interleukin-4 (IL-4), interleukin-17 (IL-17) and transforming growth factor-β (TGF-β) in PPs were evaluated by immunohistochemistry, to reflect the differentiation of T lymphocyte in PPs to helper T (Th) cell 1, Th2, Th17 and regulatory T (Treg) cell. To confirm the correlation between SAA in Coptidis Rhizoma decoction, PPs-associated immunity and intestinal epithelium permeability, SAA were administrated on an Ussing Chamber jejunum model with immunosuppressed PPs and evaluated its influences on intestinal tissue permeability and TJ proteins expression.

Results

SAA in Coptidis Rhizoma decoction could dose-dependently promote Ber absorption in jejunum segment, with the participation of PPs. The dose-dependent and dynamical regulations of SAA on permeability of intestinal tissue and TJ proteins expression level between intestinal epithelium cells occurred along with the dynamically changed T lymphocyte differentiation and immune effectors secretion in PPs. The administration of SAA on immunosuppressed PPs exhibited dose-dependent PPs activation, inducing dynamic promotion on intestinal tissue permeability and inhibition on TJ proteins expression.

Conclusion

SAA can improve the Ber absorption in small intestine, through the PPs-associated immunity induced dynamic regulation on intestinal tissue permeability and TJ proteins expression. These findings might enlighten the research of traditional Chinese medicine decoction.

Extraction, structure, pharmacological activities and drug carrier applications of Angelica sinensis polysaccharide

Angelica sinensis polysaccharide (ASP) is one of the main active components of Angelica sinensis (AS) that is widely used in traditional Chinese medicine. ASP is water-soluble polysaccharides, and it is mainly composed of glucose (Glc), galactose (Gal), arabinose (Ara), rhamnose (Rha), fucose (Fuc), xylose (Xyl) and galacturonic acid (GalUA). The extraction methods of ASP include hot water extraction and ultrasonic wave extraction, and different extraction methods can affect the yield of ASP. ASP has a variety of pharmacological activities, including hematopoietic activity, promoting immunity, antitumor, anti-inflammatory, antioxidant, anti-aging, anti-virus, liver protection, and so on. As a kind of natural polysaccharide, ASP has potential application as drug carriers. This review provides a comprehensive summary of the latest extraction and purification methods of ASP, the strategies used for monosaccharide compositional analysis plus polysaccharide structural characterization, pharmacological activities and drug carrier applications, and it can provide a basis for further study on ASP.

Recent Advances and Future Perspectives in Polymer-Based Nanovaccines

Vaccination is the most valuable and cost-effective health measure to prevent and control the spread of infectious diseases. A significant number of infectious diseases and chronic disorders are still not preventable by existing vaccination schemes; therefore, new-generation vaccines are needed. Novel technologies such as nanoparticulate systems and adjuvants can enable safe and effective vaccines for difficult target populations such as newborns, elderly, and the immune-compromised. More recently, polymer-based particles have found application as vaccine platforms and vaccine adjuvants due to their ability to prevent antigen degradation and clearance, coupled with enhanced uptake by professional antigen-presenting cells (APCs). Polymeric nanoparticles have been applied in vaccine delivery, showing significant adjuvant effects as they can easily be taken up by APCs. In other words, polymer-based systems offer a lot of advantages, including versatility and flexibility in the design process, the ability to incorporate a range of immunomodulators/antigens, mimicking infection in different ways, and acting as a depot, thereby persisting long enough to generate adaptive immune responses. The aim of this review is to summarize the properties, the characteristics, the added value, and the limitations of the polymer-based nanovaccines, as well as the process of their development by the pharmaceutical industry.

Administration Routes of Polyethylenimine-Coated PLGA Nanoparticles Encapsulating Angelica Sinensis Polysaccharide Vaccine Delivery System Affect Immune Responses

Nanoparticle vaccine delivery systems have been emerging strategies for inducing potent immune responses to prevent and treat infectious diseases and cancers. The properties of nanoparticle vaccine delivery systems, such as nanoparticle size, surface charge, and antigen release kinetics, have been extensively studied and proven to effectively influence the efficacy of vaccine responses. However, a few types of research have focused on the influence of administration routes of nanoparticle vaccines on immune responses. Herein, to investigate how the administration routes affect the immune responses of nanoparticles vaccines, we developed a nanoparticles system (NPs), in which the ovalbumin (OVA) and Angelica sinensis polysaccharide (ASP) were incorporated into poly(lactic-co-glycolic acid) (PLGA) nanoparticles and the polyethylenimine (PEI) was coated on the surface of nanoparticles. The NPs vaccine was intramuscularly and subcutaneously injected (im and sc) into mice, and the immune responses induced by these two delivery routes were compared. The results showed that both im and sc administration of NPs vaccines elicited strong antigen-specific IgG, IgG1, and IgG2a antibody responses, with no significant difference. In contrast, NP vaccines with sc administration significantly enhanced immune responses, such as enhancing the recruitment and activation of dendritic cells (DCs) in lymph nodes (LNs), promoting the antigen transport into draining lymph nodes, increasing the secretion of cytokines, improving the ratio of CD4⁺T cells to CD8⁺ T cells, activating cytotoxic T lymphocyte response, and inducing a strong cellular immune response. These results may provide a new insight onto the development of vaccine delivery systems.

Natural Polysaccharides and Their Derivates: A Promising Natural Adjuvant for Tumor Immunotherapy

The treatment process of tumor is advanced with the development of immunotherapy. In clinical experience, immunotherapy has achieved very significant results. However, the application of immunotherapy is limited by a variety of immune microenvironment. For a long time in the past, polysaccharides such as lentinan and Ganoderma lucidum glycopeptide have been used in clinic as adjuvant drugs to widely improve the immunity of the body. However, their mechanism in tumor immunotherapy has not been deeply discussed. Studies have shown that natural polysaccharides can stimulate innate immunity by activating upstream immune cells so as to regulate adaptive immune pathways such as T cells and improve the effect of immunotherapy, suggesting that polysaccharides also have a promising future in cancer therapy. This review systematically discusses that polysaccharides can directly or indirectly activate macrophages, dendritic cells, natural killer cells etc., binding to their surface receptors, inducing PI3K/Akt, mitogen-activated protein kinase, Notch and other pathways, promote their proliferation and differentiation, increasing the secretion of cytokines, and improve the state of immune suppression. These results provide relevant basis for guiding polysaccharide to be used as adjuvants of cancer immunotherapy.

The Bioactivities and Potential Clinical Values of Angelica Sinensis Polysaccharides

Angelica sinensis Radix (ASR), one of the most commonly used traditional Chinese medicines, contains many chemical components such as polysaccharides, volatile oil, flavonoids, amino acids, and organic acids, among which polysaccharides play an indispensable role in the therapeutic effect of ASR. A. sinensis polysaccharide (ASP) has many biological activities, for instance, hematopoietic, anti-tumor, and liver protection, which are closely related to the treatment of human diseases such as chronic anemia, leukemia, and diabetes. In addition, there are excellent application prospects for drug delivery in nanoparticles. This paper reviews the chemical compositions, extraction methods, biological activity, action mechanism, potential clinical applications, nanoparticles, and research prospect of ASP from 2010 to 2020, so as to provide references for its further development.

Coptis chinensis Franch polysaccharides provide a dynamically regulation on intestinal microenvironment, based on the intestinal flora and mucosal immunity

ETHNOPHARMACOLOGICAL RELEVANCE

Coptis chinensis Franch is one of the most widely used traditional Chinese herbs in China and was firstly recorded in "Shennong's Classic of Materia Medica" in the Han Dynasty. The medical records in past thousands years have fully confirmed the clinical efficacies of Coptis chinensis Franch against intestinal diseases. The polysaccharides in herbal medicines can be digested by the flora and uptaken by the Peyer's patches (PPs) in intestine. It can be reasonably presumed that the polysaccharides in Coptis chinensis Franch (CCP) should be one of the critical element in the regulation of intestinal microenvironment.

AIM OF THE STUDY

This study intended to explore the dynamic regulation of CCP on intestinal microenvironment from the perspective of the intestinal mucosal immunity and the intestinal flora, in order to provide a new research perspective for the pharmacological mechanism of Coptis chinensis Franch.

MATERIALS AND METHODS

The absorption and distribution of CCP in intestinal tissues were observed after the perfusion of FITC labeled CCP. The influences of CCP on intestinal flora were evaluated by the 16sRNA gene illumina-miseq sequencing after gavage. The regulations of CCP on intestinal mucosal immunity were evaluated by the immunohistochemical analysis of the interferon-γ (IFN-γ), interleukin-4 (IL-4), interleukin-17 (IL-17) and transforming growth factor-β (TGF-β) secretion in PPs and intestinal epithelial tissue.

RESULTS

With the self-aggregation into particles morphology, CCP can be up-taken by PPs and promote the IFN-γ, IL-4, IL-17 and TGF-β secretion in PPs in a dose-dependent manner. The CCP can also be utilized by the intestinal flora and dynamically regulate the diversity, composition and distribution of the intestinal flora. The temporal regulations of CCP on IFN-γ, IL-4, IL-17 and TGF-β secretions in intestinal epithelial tissues are consistent with the variation tendency of intestinal flora.

CONCLUSION

CCP can provide effective, dynamical and dose-dependent regulations on intestinal microenvironment, not only the intestinal flora but also the PPs and intestinal epithelium related immune response. These may be involved in the multiple biological activities of Coptis chinensis Franch.

Carbohydrate-based adjuvants

Carbohydrate adjuvants are safe and biocompatible compounds usable as sustained delivery systems and stimulants of ongoing humoral and cellular immune responses, being especially suitable for the development of vaccines against intracellular pathogens where alum is useless. The development of new adjuvants is difficult and expensive, however, in the last two years, seven new carbohydrate-based adjuvants have been patented, also there are twelve ongoing clinical trials of vaccines that contain carbohydrate-based adjuvants, as well as numerous publications on their mechanism of action and safety. More research is necessary to improve the existent adjuvants and develop innovative ones.

Antiviral activity against porcine epidemic diarrhea virus of Pogostemon cablin polysaccharide

ETHNOPHARMACOLOGICAL RELEVANCE

The dry overground parts of Pogostemon cablin (Blanco) Benth. is widely used in China as a traditional Chinese medicine for the treatment of diarrhea, vomiting, nausea and fever. Polysaccharide is an important component of Pogostemon cablin (Blanco) Benth. but has not been studied. Pogostemon cablin (Blanco) Benth. is used to treat porcine epidemic diarrhea. But it is not known whether Pogostemon cablin polysaccharides (PCPs) has the antiviral activities against porcine epidemic diarrhea virus (PEDV).

AIM OF THE STUDY

The purpose of present study is to investigate the structural characterization and the anti-PEDV activities of PCPs.

MATERIALS AND METHODS

PCPs were prepared by water extraction and alcohol precipitation method and purified with DEAE-52 cellulose column and Sephadex G-100 column. Then, the structural characterization of the polysaccharides including the infrared spectrum, molecular weight and monosaccharide composition were analyzed. Afterwards, the antiviral effect of PCPs against PEDV on IPEC-J2 cells was studied by MTT method and real-time PCR method. Additionally, the effects of PCPs on PEDV adsorption, penetration and replication were analyzed by real-time PCR method. Furthermore, we also investigate whether the anti-oxidative effects of PCPs were important to the anti-PEDV activities.

RESULTS

Four polysaccharides were obtained and named as PCP1.1 (31.3 kDa), PCP1.2 (3.5 kDa), PCP2.1 (9.1 kDa) and PCP2.2 (8.3 kDa). PCP1.1, PCP1.2 and PCP2.1 were composed of fucose, arabinose, galactose, glucose, mannose, galacturonic acid and glucuronic acid; and PCP2.2 was composed of arabinose, galactose, glucose, galacturonic acid and glucuronic acid. All PCPs showed anti-PEDV activities. PCP1.1 and PCP1.2 inhibited PEDV replication, while PCP2.1 and PCP2.2 inhibited PEDV penetration and replication. All PCPs showed anti-oxidative effects, which were important to the anti-PEDV activities.

CONCLUSIONS

The treatment effect of Pogostemon cablin (Blanco) Benth. on porcine epidemic diarrhea might be related to the anti-PEDV effect of PCPs. Furthermore, the anti-oxidative effects of PCPs play important roles in their antiviral activities against PEDV.

Lentinan-Functionalized Graphene Oxide Is an Effective Antigen Delivery System That Modulates Innate Immunity and Improves Adaptive Immunity

Graphene oxide (GO) and lentinan have received great attention because of their utility in biomedical applications. Graphene oxide is utilized in drug- and vaccine-delivery systems due to its biocompatibility, large surface area, and outstanding adsorption capability, while lentinan has immunity-enhancing effects. In this study, we synthesized and characterized GO grafted with lentinan (LNT) as an adjuvant and investigated how to impact the immune responses. Lentinan-modified GO (GO-LNT) facilitated antigen uptake in macrophages and improved the efficiency of antigen application in vitro. Furthermore, in vivo, compared with GO/OVA, GO-LNT/OVA decreased the release rate of ovalbumin (OVA) to sustain long-term immune responses and boost the levels of IgG and IgG subtypes. Hence, we can infer that the effects of GO-LNT were a result of the increased amounts of antigen uptake by cells. Overall, our studies demonstrated that GO-LNT could suffice for a safe and effective vaccine-delivery system as well as an excellent adjuvant that both elicits a long-term immune memory response and potentiates cellular and humoral immunity.

Immune-adjuvant activity of lentinan-modified calcium carbonate microparticles on a H5N1 vaccine

In recent years, the high prevalence of avian influenza viruses especially H₅N₁ subtype isolated from poultry and human has become a major public health concern. Vaccination is still a major strategy for preventing H₅N₁ infections. Lentinan (LNT), a β-1,3-glucohexaose with β-1,6-branches, is extracted from Lentinus edodes and has been extensively studied for its immunoenhancement effects. In this study, we synthesized and characterized calcium carbonate (CaCO₃) microparticles which modified with LNT as an adjuvant for H₅N₁ vaccine and investigated their ability to enhance immune responses. We prepared spherical and uniform CaCO₃-LNT microparticles with a mean hydrodynamic size was around 2 μm. The H₅N₁ antigen-loaded CaCO₃-LNT particles were injected into mice to evaluate their effectiveness as an adjuvant for H₅N₁ vaccines. The results demonstrated that CaCO₃-LNT/H₅N₁ significantly enhanced the expression of MHC-II and CD86 in lymph node dendritic cells, and increased the ratio of CD4⁺ to CD8⁺ T cells in lymphocytes. Moreover, CaCO₃-LNT/H₅N₁ surprisingly increased the HI titers and induced the secretion of IgG subtypes (IgG1 and IgG2b) and Th-associated cytokines (TNF-α, IFN-γ and IL-4) in immunized mice. Therefore, by combining with the immunostimulatory activity of LNT and the drug/antigen delivery capabilities of CaCO₃, the CaCO₃-LNT/H₅N₁ could induce a stronger cellular and humoral immune response and could be a potential adjuvant for the H₅N₁ vaccine.

Extraction and structural analysis of Angelica sinensis polysaccharide with low molecular weight and its lipid-lowering effect on nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is one of the prevalent and typical chronic liver diseases. In this study, we extracted a novel Angelica sinensis polysaccharide (ASP) with low molecular weight (MW) of 3.2 kDa through optimized "one-step" purification process. The major monosaccharide components of ASP were mannose, rhamnose, glucuronic acid, galactose, arabinose, and xylose with weight ratio of 0.23:0.17:14.41:0.39:1.68:0.87, respectively. Herein, "small" ASP could serve as an effective therapeutic option for NAFLD both in free fatty acid-induced L02 models and in high-fat diet-induced mice models. Results revealed that low MW ASP dose-dependently decreased TG, TC in vitro and TG, TC, ALT, HDL-C, and LDL-C in vivo. Oil Red O-positive area and Nile red fluorescence intensity decreased in ASP treatment groups both in vitro and in vivo which suggested ASP could reduce lipid accumulation and fatty regeneration. Hematoxylin-eosin staining results shown a decrease in hepatocytes ballooning indicating that ASP could ameliorate liver lipid degeneration. Briefly, a novel polysaccharide with low MW was successfully obtained which can prospectively act as NAFLD therapy.

Preparation of lentinan-calcium carbonate microspheres and their application as vaccine adjuvants

Adjuvants improve vaccine potency by enhancing immunogenicity and sustaining long-term immune responses. Lentinan (LNT), a β-1,3-glucohexaose with β-1,6-branches, is extracted from the mushroom Lentinus edodes and functions as an effective immunostimulatory drug. Previous studies have demonstrated the adjuvant activity of calcium carbonate (CaCO₃) microspheres as well as their use as antigen delivery systems. In this study, we successfully loaded CaCO₃ microspheres with LNT and evaluated their physicochemical characteristics prior to the adsorption of ovalbumin. Our experimental results demonstrated that LNT-CaCO₃ significantly enhanced lymphocyte proliferation, and boosted the frequency of CD69 + B cells and the ratio of CD4+ to CD8 + T cells in spleen lymphocytes. Moreover, LNT-CaCO₃ unexpectedly induced the secretion of IgG and Th-associated cytokines (IL-2, IL-4, IFN-γ, and TNF-α) in immunized mice. Therefore, LNT-CaCO₃ microspheres induce robust cellular and humoral immune responses and have potential utility as vaccine delivery systems.

Adjuvant activities of CTAB-modified Polygonatum sibiricum polysaccharide cubosomes on immune responses to ovalbumin in mice

Recently, the cubosomes have been widely studied as drug carriers. It has been described that cubosomes could further stimulate the immune response after carrying the immune enhancer. Polygonatum sibiricum polysaccharide (PSP), one of the most important biologically active ingredients of Polygonatum sibiricum, has been reported as an immunostimulant to improve immune responses. This study was aimed to observe the immunomodulation effects of ovalbumin (OVA) absorbed cetyltrimethylammonium bromide-modified Polygonatum sibiricum polysaccharide cubosomes (CTAB-modified PSP-Cubs/OVA). Firstly, the antigen uptake of CTAB-modified PSP-Cubs/OVA by macrophages was determined in vitro. After that, mice were immunized with CTAB-modified PSP-Cubs/OVA. The activation of dendritic cells in lymph nodes, activation of lymphocyte, ratios of CD4⁺ to CD8⁺, the concentrations of OVA-specific IgG in serum and the cytokines concentrations were analyzed. As the results showed, CTAB-modified PSP-Cubs/OVA could promote the production of OVA-specific IgG in serum. The ratio of CD4⁺ to CD8⁺ in CTAB-modified PSP-Cubs/OVA group was significantly increased compared with other groups. CTAB-modified PSP-Cubs/OVA could significantly activate dendritic cells and promote lymphocyte proliferation. The results indicated that CTAB-modified PSP-Cubs/OVA could promote the secretion of related cytokines and the proliferation of lymphocytes, stimulate the cellular immune response and increase the level of humoral immunity. Above all, CTAB-modified PSP-Cubs had good adjuvant activity.

Polyethylenimine-coated PLGA nanoparticles-encapsulated Angelica sinensis polysaccharide as an adjuvant to enhance immune responses

Nanoparticle delivery systems have been widely investigated as new vaccines strategy to enhance the immune responses to antigens against infectious diseases. The positively charged nanoparticles could efficiently improve the immune responses due to targeting and activating the antigen-presenting cells. In this study, the immunopotentiator Angelica sinensis polysaccharide (ASP) was encapsulated into Poly (lactic-co-glycolic acid) (PLGA) nanoparticles, and the polyethylenimine, one of the cationic polymers, was used to coat nanoparticles to develop a new nanoparticle delivery system (ASP-PLGA-PEI) with positively charged. The ASP-PLGA-PEI nanoparticles significantly activated macrophages, and promoted the expression of the MHCII and CD86 and the production of IL-1β and IL-12p70 cytokines of macrophages. Furthermore, the antigen adsorbed on the surface of the ASP-PLGA-PEI nanoparticles enhanced the antigen uptake by macrophages. Moreover, the mice immunized with PCV2 antigen adsorbed ASP-PLGA-PEI nanoparticles significantly enhanced PCV2-specific IgG immune response and the levels of cytokines, induced a mixed Th1/Th2 immune response with Th1 bias compared with other groups. These findings demonstrate that the positively charged nanoparticles (ASP-PLGA-PEI) have the potential to serve as an effective vaccine delivery and adjuvant system to induce vigorous and long-term immune responses.