Immunopotentiating Polyphosphazene Delivery Systems: Supramolecular Self-Assembly and Stability in the Presence of Plasma Proteins.

Studies on the biological performance of nanomedicines have been increasingly focused on the paradigm shifting role of the protein corona, which is imminently formed once the formulation is placed in a complex physiological environment. This phenomenon is predominantly studied in the context of protein adsorption science, while such interactions for water-soluble systems remain virtually unexplored. In particular, the importance of plasma protein binding is yet to be understood for pharmaceuticals designed on the basis of supramolecular architectures, which generally lack well-defined surfaces. Water-soluble ionic polyphosphazenes, clinically proven immunoadjuvants and vaccine delivery vehicles, represent an example of a system that requires supramolecular coassembly with antigenic proteins to attain an optimal immunopotentiating effect. Herein, the self-assembly behavior and stability of noncovalently bound complexes on the basis of a model antigen─hen egg lysozyme─and polyphosphazene adjuvant are studied in the presence of plasma proteins utilizing isothermal calorimetry, asymmetric flow field flow fractionation, dynamic light scattering, and size exclusion chromatography methods. The results demonstrate that although plasma proteins, such as human serum albumin (HSA), show detectable avidity to polyphosphazene, the strength of such interactions is significantly lower than that for the model antigen. Furthermore, thermodynamic parameters indicate different models of binding: entropy driven, which is consistent with the counterion release mechanism for albumin versus electrostatic interactions for lysozyme, which are characterized by beneficial enthalpy changes. In vitro protein release experiments conducted in Franz diffusion cells using enzyme-linked immunoassay detection suggest that the antigen-adjuvant complex stability is not adversely affected by the presence of the most physiologically abundant protein, which confirms the importance of the delivery modality for this immunoadjuvant. Moreover, HSA shows an unexpected stabilizing effect on complexes with high antigen load─an important consideration for further development of polyphosphazene adjuvanted vaccine formulations and their functional assessment.

Economic evaluation of adjuvant therapy with osimertinib in patients with early-stage non-small cell lung cancer and mutated EGFR.

PURPOSE: The ADAURA trial demonstrated the superiority of osimertinib over a placebo with regard to disease-free survival, showing it to be indicated as an adjuvant therapy for treatment of non-small cell lung cancer with mutated epidermal growth factor receptor (EGFR). The aim of the present study was to conduct a cost-utility analysis and an analysis of the budgetary impact of adjuvant therapy with osimertinib in patients with non-small cell lung cancer with mutated EGFR who had undergone resection surgery with curative intent. METHODS: Analyses were based on the outcomes of the ADAURA clinical trial and were conducted through a Spanish National Health Service perspective. The outcome measures used were quality-adjusted life years (QALY). RESULTS: The average overall cost of adjuvant treatment with osimertinib over a period of 100 months in the overall sample of trial patients (stages IB-IIIA) was 220,961 €, compared with 197,849 € in the placebo group. Effectiveness, estimated according to QALY, was 6.26 years in the osimertinib group and 5.96 years in the placebo group, with the incremental cost-utility ratio being 77,040 €/QALY. With regard to the budgetary impact, it was estimated that, in 2021, approximately 1130 patients would be subsidiaries to receive osimertinib. This pertains to a difference of 17,375,330 € over 100 months to fund this treatment relative to no treatment. CONCLUSION: Taking into account a Spanish threshold of 24,000 €/QALY, the reduction in the acquisition cost of osimertinib will have to be greater than 10%, to obtain a cost-effective alternative.

Polyphosphazene: A New Adjuvant Platform for Cocaine Vaccine Development.

Cocaine is a highly addictive drug that has seen a steady uptrend causing severe health problems worldwide. Currently, there are no approved therapeutics for treating cocaine use disorder; hence, there is an urgent need to identify new medications. Immunopharmacotherapeutics is a promising approach utilizing endogenous antibodies generated through active vaccination, and if properly programmed, can blunt a drug's psychoactive and addictive effects. However, drug vaccine efficacy has largely been limited by the modest levels of antibodies induced. Herein, we explored an adjuvant system consisting of a polyphosphazene macromolecule, specifically poly[di(carboxylatoethylphenoxy)-phosphazene] (PCEP), a biocompatible synthetic polymer that was solicited for improved cocaine conjugate vaccine delivery performance. Our results demonstrated PCEP's superior assembling efficiency with a cocaine hapten as well as with the combined adjuvant CpG oligodeoxynucleotide (ODN). Importantly, this combination led to a higher titer response, balanced immunity, successful sequestering of cocaine in the blood, and a reduction in the drug in the brain. Moreover, a PCEP-cocaine conjugate vaccine was also found to function well via intranasal administration, where its efficacy was demonstrated through the antibody titer, affinity, mucosal IgA production, and a reduction in cocaine's locomotor activity. Overall, a comprehensive evaluation of PCEP integrated within a cocaine vaccine established an advance in the use of synthetic adjuvants in the drugs of abuse vaccine field.

The production and influence of anti-Vibrio parahaemolytics IgY against experimental infection of V. parahaemolyticus in cultured Fenneropenaeus indicus.

The increasing number of antibiotic-resistant bacteria emphasizes the need to find alternatives to complement antibiotics. Immunotherapy may also be used as a complementary treatment against pathogens that are difficult to treat with traditional antibiotics. Eggs are normal dietary components and there is practically no risk of toxic side effects of IgY given orally. In the present study, pathogenic Vibrio parahaemolyticus was isolated from infected shrimp and studied their virulence factors including LD50 (by challenging with Fenneropenaeus indicus), proteolytic and hemolytic activities. The edible antibody IgY was raised by injecting the antigen of Extra Cellular Products (ECP) of V. parahaemolyticus to Gallus gallus domesticus during layoff period with and without the herbal immunoadjuvants, Asparagus racemosus and Glycine max (V.p wo: V. parahaemolyticus ECP without adjuvant; V.p A: V. parahaemolyticus ECP with A. racemosus and V.p G: V. parahaemolyticus ECP with G. max). Eggs were collected after five weeks of immunization and anti- V. parahaemolyticus IgY was extracted and purified. Physicochemical properties of the immunized Chickens' serum and anti- V. parahaemolyticus IgY's cross reactivity, growth inhibition assay, single radial immunodiffusion assay and bacterial agglutination were studied. The results revealed that, the serum protein parameters were significantly (P ≤ 0.001) increased in experimental groups from control group. The antibody raised with immunoadjuvants had significantly (P ≤ 0.001) higher cross reactivity, growth inhibition, single radial immunoassay and bacterial agglutination when compared with and without immunoadjuvant and control groups. Further the control and experimental anti-V. parahaemolytics IgY coated artificial diets were fed to F. indicus for 60 days. After 30 and 60 dpv (days of post vaccination), shrimps from each groups were challenged with virulent V. parahaemolyticus and studied the survival, haematological and immunological parameters. The IgY coated diets (V. p A and V.p G) fed shrimps had decreased cumulative mortality, significantly (P ≤ 0.001) improved coagulase activity, total haemocyte count and oxyhaemocyanin. The immunological parameters such as prophenoloxidase, intracellular anion production, lysozyme production and phagocytosis also improved significantly (P ≤ 0.001) in IgY treated shrimps.

In Vivo and In Vitro Potency of Polyphosphazene Immunoadjuvants with Hepatitis C Virus Antigen and the Role of Their Supramolecular Assembly.

Two well-defined synthetic polyphosphazene immunoadjuvants, PCPP and PCEP, were studied for their ability to potentiate the immune response to the hepatitis C virus (HCV) E2 glycoprotein antigen in vivo. We report that PCEP induced significantly higher serum neutralization and HCV-specific IgG titers in mice compared to other adjuvants used in the study: PCPP, Alum, and Addavax. PCEP also shifted the response toward the desirable balanced Th1/Th2 immunity, as evaluated by the antibody isotype ratio (IgG2a/IgG1). The in vivo results were analyzed in the context of antigen-adjuvant molecular interactions in the system and in vitro immunostimulatory activity of formulations. Asymmetric flow field flow fractionation (AF4) and dynamic light scattering (DLS) analysis showed that both PCPP and PCEP spontaneously self-assemble with the E2 glycoprotein with the formation of multimeric water-soluble complexes, which demonstrates the role of polyphosphazene macromolecules as vaccine delivery vehicles. Intrinsic in vitro immunostimulatory activity of polyphosphazene adjuvants, which was assessed using a mouse macrophage cell line, revealed comparable activities of both polymers and did not provide an explanation of their in vivo performance. However, PCEP complexes with E2 displayed greater stability against agglomeration and improved in vitro immunostimulatory activity compared to those of PCPP, which is in line with superior in vivo performance of PCEP. The results emphasize the importance of often neglected antigen-polyphosphazene self-assembly mechanisms in formulations, which can provide important insights on their in vivo behavior and facilitate the establishment of a structure-activity relationship for this important class of immunoadjuvants.

Physicochemical properties of anti Vibrio harveyi egg yolk antibody (IgY) and its immunological influence in Indian white shrimp Fenneropenaeus indicus.

Edible antibodies specific to host pathogens is an attractive approach to establish protective immunity, especially against gastrointestinal pathogens both in humans and animals. The edible antibody of anti-Vibrio harveyi IgY (anti-V. h IgY) was produced by antigen mixed with immunoadjuvant Asparagus racemosus and Glycine max. Hens were immunized and eggs were collected five weeks after the immunization. Anti-V. harveyi IgY stability in different digestive enzymes such as trypsin and chymotrypsin were evaluated to determine its ability to withstand in the gastrointestinal tract of F. indicus. Specific binding activity and concentration (average 9.5% of total IgY content) of the anti-V. h IgY were determined by the ELISA using V. harveyi antigen. Further the anti-V. h IgY diets including V.h wo, V.h A, V.h G and control diets were fed to F. indicus for 60 days. After 30 and 60 of feeding, group of shrimps were challenged with virulent V. harveyi. After the respective days of feeding, haematological and immunological changes were studied. The parameters including total haemocyte count (THC), coagulase activity, oxyhaemocyanin level, prophenoloxidase, intracellular superoxide anion production, lysozyme, phagocytosis and bacterial agglutinin had significantly (P ≤ .001) increased in the experimental groups in comparission with the control diet fed shrimps. The anti-V. h IgY coated diets helped to reduce the Vibrio load and boosted the immune system in F. indicus's against V. harveyi challenge. The research work shows the potential applications of egg yolk antibodies as anti-bacterial prophylactic uses for infectious diseases and suggests an edible antibody concept as an alternative to conventional antibiotics.

PCPP-Adjuvanted Respiratory Syncytial Virus (RSV) sF Subunit Vaccine: Self-Assembled Supramolecular Complexes Enable Enhanced Immunogenicity and Protection.

PCPP, a well-defined polyphosphazene macromolecule, has been studied as an immunoadjuvant for a soluble form of the postfusion glycoprotein of respiratory syncytial virus (RSV sF), which is an attractive vaccine candidate for inducing RSV-specific immunity in mice and humans. We demonstrate that RSV sF-PCPP formulations induce high neutralization titers to RSV comparable to alum formulations even at a low PCPP dose and protect animals against viral challenge both in the lung and in the upper respiratory tract. PCPP formulations were also characterized by Th1-biased responses, compared to Th2-biased responses that are more typical for RSV sF alone or RSV sF-alum formulations, suggesting an inherent immunostimulating activity of the polyphosphazene adjuvant. We defined these immunologically active RSV sF-PCPP formulations as self-assembled water-soluble protein-polymer complexes with distinct physicochemical parameters. The secondary structure and antigenicity of the protein in the complex were fully preserved during the spontaneous aqueous self-assembly process. These findings further advance the concept of polyphosphazene immunoadjuvants as unique dual-functionality adjuvants integrating delivery and immunostimulating modalities in one water-soluble molecule.

Percutaneous Intratumoral Immunoadjuvant Gel Increases the Abscopal Effect of Cryoablation for Checkpoint Inhibitor Resistant Cancer.

Percutaneous cryoablation is a common clinical therapy for metastatic and primary cancer. There are rare clinical reports of cryoablation inducing regression of distant metastases, known as the "abscopal" effect. Intratumoral immunoadjuvants may be able to augment the abscopal rate of cryoablation, but existing intratumoral therapies suffer from the need for frequent injections and inability to confirm target delivery, leading to poor clinical trial outcomes. To address these shortcomings, an injectable thermoresponsive gel-based controlled release formulation is developed for the FDA-approved Toll-like-receptor 7 (TLR7) agonist imiquimod ("Imigel") that forms a tumor-resident depot upon injection and contains a contrast agent for visualization under computed tomography (CT). The poly-lactic-co-glycolic acid-polyethylene glycol-poly-lactic-co-glycolic acid (PLGA-PEG-PLGA)-based amphiphilic copolymer gel's underlying micellar nature enables high drug concentration and a logarithmic release profile that is additive with the neo-antigen release from cryoablation, requiring only a single injection. Rheological testing demonstrated the thermoresponsive increase in viscosity at body temperature and radio-opacity via microCT. Its ability to significantly augment the abscopal rate of cryoablation is demonstrated in otherwise immunotherapy resistant metastatic tumors in two aggressive colorectal and breast cancer dual tumor models with an all or nothing response, responders generally demonstrating complete regression of bilateral tumors in 90-day survival studies.

Immunotherapy with STING and TLR9 agonists promotes synergistic therapeutic efficacy with suppressed cancer-associated fibroblasts in colon carcinoma.

The innate immune sensing of nucleic acids using effective immunoadjuvants is critical for increasing protective immune responses against cancer. Stimulators of interferon genes (STING) and toll-like receptor 9 (TLR9) agonists are considered promising candidates in several preclinical tumor models with the potential to be used in clinical settings. However, the effects of such treatment on tumor stroma are currently unknown. In this study, we investigated the immunotherapeutic effects of ADU-S100 as a STING agonist and CpG ODN1826 as a TLR9 agonist in a preclinical model of colon carcinoma. Tumor-bearing mice were treated intratumorally on days 10 and 16 post-tumor inoculation with ADU-S100 and CpG ODN1826. Cytokine profiles in the tumor and spleen, tumor cell apoptosis, the infiltration of immune cells, and cancer-associated fibroblasts (CAFs) in the tumor microenvironment (TME) were evaluated to identify the immunological mechanisms after treatment. The powerful antitumor activity of single and combination treatments, the upregulation of the expression of pro-inflammatory cytokines in the tumor and spleen, and the recruitment and infiltration of the TME by immune cells revealed the synergism of immunoadjuvants in the eradication of the colon carcinoma model. Remarkably, the significant downregulation of CAFs in the TME indicated that suppression of tumorigenesis occurred after immunoadjuvant therapy. The results illustrate the potential of targeting the STING and TLR9 pathways as powerful immunoadjuvants in the treatment of preclinical colon carcinoma and the possibility of harnessing these pathways in future therapeutic approaches.

Ferroptosis and Necroptosis Produced Autologous Tumor Cell Lysates Co-Delivering with Combined Immnoadjuvants as Personalized In Situ Nanovaccines for Antitumor Immunity.

Nanovaccine-based immunotherapy has been considered as a major pillar to stimulate the host immune system to recognize and eradicate tumor cells as well as establish a long-term immune memory to prevent tumor relapse and metastasis. However, the weak specificity and low cross-presentation of antigens, as well as the immunosuppressive microenvironments of tumor tissues, are still the major obstacles on exerting the therapeutic performance of tumor nanovaccines sufficiently. Herein, we design and construct cytosine guanine dinucleotide (CpG) oligodeoxynucleotide (ODN)-loaded aluminum hydroxyphosphate nanoparticles covered by Fe-Shikonin metal-phenolic networks (MPNs) (Alum-CpG@Fe-Shikonin NPs) as personalized in situ nanovaccines for antitumor immunity. Upon internalization by tumor cells, the shell of Fe-Shikonin MPNs will disassemble into Fe2+ and Shikonin to elicit the immunogenic cell death of tumor cells through ferroptosis and necroptosis. Then, dying tumor cell-released autologous tumor cell lysates will be absorbed by Alum NPs and codelivered with CpG ODN to professional antigen-presenting cells temporally and spatially to activate multistep cascade antitumor immune responses, including dendritic cell maturation, antigen cross-presentation, natural killer cell and cytotoxic T lymphocyte infiltrations, and tumor-associated macrophage repolarization. Benefiting from the synergistic effects of Alum NPs, CpG ODN, and Fe-Shikonin MPNs, our Alum-CpG@Fe-Shikonin NPs exhibit drastic cytotoxicity and accurate selectivity on eradicating primary tumor, strong abscopal effect on inhibiting distant tumor, and a long-term immune memory effect on preventing tumor metastasis and recurrence. Because our report provides a feasible strategy to in situ make full use of autologous tumor cell lysates, which present an entire spectrum of the patient's personal epitopes without complicated ex vivo processes, such as extraction, purification, and sequencing, it may promote the development of personalized nanovaccines for antitumor immunity.

Fe(III)-Shikonin supramolecular nanomedicines as immunogenic cell death stimulants and multifunctional immunoadjuvants for tumor vaccination.

Immunoadjuvants, as an indispensable component of tumor vaccines, can observably enhance the magnitude, breadth, and durability of antitumor immunity. However, current immunoadjuvants suffer from different issues such as weak immunogenicity, inadequate cellular internalization, poor circulation time, and mono-functional bioactivity. Methods: Herein, we construct Fe3+-Shikonin metal-phenolic networks (FeShik) nanomedicines as immunogenic cell death (ICD) stimulants and multifunctional immunoadjuvants for tumor vaccination. The multifunctionality of FeShik nanomedicines is investigated by loading ovalbumin (OVA) as the model antigen to construct OVA@FeShik nanovaccines or 4T1 tumor cell fragment (TF) as homologous antigen to construct TF@FeShik nanovaccines. In vitro examinations including GSH responsive, •OH generation, colloid stability, cellular uptake, cytotoxicity mechanism of ferroptosis and necroptosis, ICD effect, the promotion of DC maturation and antigen cross-presentation were studied. In vivo observations including pharmacokinetics and biodistribution, antitumor effect, abscopal effect, immune memory effect, and biosafety were performed. Results: The presence of FeShik nanomedicines can significantly prolong the blood circulation time of antigens, increasing the bioavailability of antigens. Upon phagocytosis by tumor cells, FeShik nanomedicines can disassemble into Fe2+ and Shikonin in response to tumor microenvironments, leading to ICD of tumor cells via ferroptosis and necroptosis. Consequently, ICD-released autologous tumor cell lysates and pro-inflammatory cytokines not only stimulate DC maturation and antigen cross-presentation, but also promote macrophage repolarization and cytotoxic T lymphocyte infiltration, resulting in the activation of adaptive immune responses toward solid tumors. Conclusion: In a word, our FeShik supramolecular nanomedicines integrate bioactivities of ICD stimulants and immunoadjuvants, such as eradicating tumor cells, activating antitumor immune responses, modulating immunosuppressive tumor microenvironments, and biodegradation after immunotherapy. Encouraged by the diversity of polyphenols and metal ions, our research may provide a valuable paradigm to establish a large library for tumor vaccination.

Anti-tumor antibody isotype response can be modified with locally administered immunoadjuvants.

In situ vaccination with immunostimulatory compounds is a demonstrated means to treat tumors preclinically. While these therapeutic effects have been attributed to the actions of T cells or innate immune activation, characterisation of the humoral immune response is seldom performed. This study aims to identify whether the injection of immunoadjuvants, Addavax (Adda) and cytosine-phosphorothioate-guanine oligodeoxynucleotide (CpG), intratumorally can influence the antibody response. Specifically, whether intratumoral injection of immunoadjuvants can alter the tumor-specific antibody target, titre and isotype. Following this, the study aimed to investigate whether serum obtained from in situ vaccinated mice could neutralise circulating tumor cells. Serum was obtained from mice bearing B16F10-OVA-Luc-GFP tumors treated with immunoadjuvants. Antibody targets' titre and isotype were assessed by indirect ELISA. The ability of serum to neutralise circulating cancer cells was evaluated in a B16F10 pseudo-metastatic model. It was observed that tumor-bearing mice mount a specific anti-tumor antibody response. Antibody titre and target were unaffected by in situ vaccination with immunoadjuvants; however, a higher amount of IgG2c was produced in mice receiving Adda plus CpG. Serum from in situ vaccinated mice was unable to neutralise circulating B16F10 cells. Thus, this study has demonstrated that anti-tumor antibody isotype may be modified using in situ vaccination; however, this alone is not sufficient to neutralise circulating cancer cells.

Reactive oxygen species-powered cancer immunotherapy: Current status and challenges.

Reactive oxygen species (ROS) are crucial signaling molecules that can arouse immune system. In recent decades, ROS has emerged as a unique therapeutic strategy for malignant tumors as (i) it can not only directly reduce tumor burden but also trigger immune responses by inducing immunogenic cell death (ICD); and (ii) it can be facilely generated and modulated by radiotherapy, photodynamic therapy, sonodynamic therapy and chemodynamic therapy. The anti-tumor immune responses are, however, mostly downplayed by the immunosuppressive signals and dysfunction of effector immune cells within the tumor microenvironment (TME). The past years have seen fierce developments of various strategies to power ROS-based cancer immunotherapy by e.g. combining with immune checkpoints inhibitors, tumor vaccines, and/or immunoadjuvants, which have shown to potently inhibit primary tumors, metastatic tumors, and tumor relapse with limited immune-related adverse events (irAEs). In this review, we introduce the concept of ROS-powered cancer immunotherapy, highlight the innovative strategies to boost ROS-based cancer immunotherapy, and discuss the challenges in terms of clinical translation and future perspectives.

Cationic PLGA Nanoparticle Formulations as Biocompatible Immunoadjuvant for Serum Production and Immune Response against Bothrops jararaca Venom.

Snakebite envenoming represents a worldwide public health issue. Suitable technologies have been investigated for encapsulated recombinant or native proteins capable of inducing an effective and long-lasting adaptive immune response. Nanoparticles are colloidal dispersions that have been used as drug delivery systems for bioactive biological compounds. Venom-loaded nanoparticles modulate the protein release and activate the immune response to produce specific antibodies. In this study, biocompatible cationic nanoparticles with Bothrops jararaca venom were prepared to be used as a novel immunoadjuvant that shows a similar or improved immune response in antibody production when compared to a conventional immunoadjuvant (aluminum hydroxide). We prepared stable, small-sized and spherical particles with high Bothrops jararaca venom protein association efficiency. The high protein loading efficiency, electrophoresis, and zeta potential results demonstrated that Bothrops jararaca venom is adsorbed on the particle surface, which remained as a stable colloidal dispersion over 6 weeks. The slow protein release occurred and followed parabolic diffusion release kinetics. The in vivo studies demonstrated that venom-loaded nanoparticles were able to produce an immune response similar to that of aluminum hydroxide. The cationic nanoparticles (CNp) as carriers of bioactive molecules, were successfully developed and demonstrated to be a promising immunoadjuvant.

Stereotactic Body Radiotherapy Immunological Planning-A Review With a Proposed Theoretical Model.

In the stereotactic body radiotherapy (SBRT) and immunotherapy era, we are moving toward an "immunological radiation plan", i.e., radiation scheduling with abscopal effect as a vital endpoint as well. The literature review of part A enumerates the advantages of the intermediate dose of SBRT 6-10 Gy per fraction, appropriate use of dose painting, proper timing with immunotherapy, and the potential of immunoadjuvants to maximize cell kill in the irradiated lesions, found to have improved the abscopal effects. Part B summarizes part A, primarily the findings of animal trials, forming the basis of the tenets of the proposed model given in part C to realize the true abscopal potential of the SBRT tumor cell kill of the index lesions. Part C proposes a theoretical model highlighting tumor vasculature integrity as the central theme for converting "abscopal effect by chance" to "abscopal effect by design" using a harmonized combinatorial approach. The proposed model principally deals with the use of SBRT in strategizing increased cell kill in irradiated index tumors along with immunomodulators as a basis for improving the consistency of the abscopal effect. Included is the possible role of integrating immunotherapy just after SBRT, "cyclical" antiangiogenics, and immunoadjuvants/immune metabolites as abscopal effect enhancers of SBRT tumor cell kill. The proposed model suggests convergence research in adopting existing numerous SBRT abscopal enhancing strategies around the central point of sustained vascular integrity to develop decisive clinical trial protocols in the future.

Plant-derived immuno-adjuvants in vaccines formulation: a promising avenue for improving vaccines efficacy against SARS-CoV-2 virus.

The SARS-CoV-2 outbreak has posed a plethora of problems for the global healthcare system and socioeconomic burden. Despite valiant efforts to contain the COVID-19 outbreak, the situation has deteriorated to the point that there are no viable preventive therapies to treat this disease. The case count has skyrocketed globally due to the newly evolved variants. Despite vaccination drives, the re-occurrence of recent pandemic waves has reinforced the importance of innovation/utilization of immune-booster to achieve appropriate long-term vaccine protection. Plant-derived immuno-adjuvants, which have multifaceted functions, can impede infections by boosting the immune system. Many previous studies have shown that formulation of vaccines using plant-derived adjuvant results in long-lasting immunity may overcome the natural tendency of coronavirus immunity to wane quickly. Plant polysaccharides, glycosides, and glycoprotein extracts have reportedly been utilized as enticing adjuvants in experimental vaccines, such as Advax, Matrix-M, and Mistletoe lectin, which have been shown to be highly immunogenic and safe. When employed in vaccine formulation, Advax and Matrix-M generate long-lasting antibodies, a balanced robust Th1/Th2 cytokine profile, and the stimulation of cytotoxic T cells. Thus, the use of adjuvants derived from plants may increase the effectiveness of vaccines, resulting in the proper immunological response required to combat COVID-19. A few have been widely used in epidemic outbreaks, including SARS and H1N1 influenza, and their use could also improve the efficacy of COVID-19 vaccines. In this review, the immunological adjuvant properties of plant compounds as well as their potential application in anti-COVID-19 therapy are thoroughly discussed.

Inhalable Polymeric Micro and Nano-immunoadjuvants for Developing Therapeutic Vaccines in the Treatment of Non-small Cell Lung Cancer.

Non-small cell lung cancer (NSCLC) is a leading cause of death in millions of cancer patients. Lack of diagnosis at an early stage in addition to no specific guidelines for its treatment, and a higher rate of treatment- related toxicity further deteriorate the conditions. Current therapies encompass surgery, chemotherapy, radiation therapy, and immunotherapy according to the pattern and the stage of lung cancer. Among all, with a longlasting therapeutic action, reduced side-effects, and a higher rate of survival, therapeutic cancer vaccine is a new, improved strategy for treating NSCLC. Immunoadjuvants are usually incorporated into the therapeutic vaccines to shield the antigen against environmental and physiological harsh conditions in addition to boosting the immune potential. Conventional immunoadjuvants are often associated with an inadequate cellular response, poor target specificity, and low antigen load. Recently, inhalable polymeric nano/micro immunoadjuvants have exhibited immense potential in the development of therapeutic vaccines for the treatment of NSCLC with improved mucosal immunization. The development of polymeric micro/nano immunoadjuvants brought a new era for vaccines with increased strength and efficiency. Therefore, in the present review, we explained the potential application of micro/nano immunoadjuvants for augmenting the stability and efficacy of inhalable vaccines in the treatment of NSCLC. In addition, the role of biodegradable, biocompatible, and non-toxic polymers has also been discussed with case studies.

Cationic Nanostructures as Adjuvants for Vaccines.

Spherical or discoidal lipid polymer nanostructures bearing cationic charges successfully adsorb a variety of oppositely charged antigens (Ag) such as proteins, peptides, nucleic acids, or oligonucleotides. This report provides instructions for the preparation and physical characterization of four different cationic nanostructures able to combine and deliver antigens to the immune system: (1) dioctadecyl dimethylammonium bromide (DODAB) bilayer fragments (DODAB BF); (2) polystyrene sulfate (PSS) nanoparticles (NPs) covered with one cationic dioctadecyl dimethylammonium bromide bilayer (DODAB) named (PSS/DODAB); (3) cationic NPs of biocompatible polymer poly(methyl methacrylate) (PMMA) prepared by emulsion polymerization of the methyl methacrylate (MMA) monomer in the presence of DODAB BF (PMMA/DODAB NPs); (4) antigen NPs (NPs) where the cationic polymer poly(diallyl dimethyl ammonium chloride) (PDDA) directly combined at nontoxic and low dose with the antigen (Ag); when the oppositely charged model antigen is ovalbumin (OVA), NPs are named PDDA/OVA. These nanostructures provide adequate microenvironments for carrying and delivering antigens to the antigen-presenting cells of the immune system.

Immunopotentiating and Delivery Systems for HCV Vaccines.

Development of preventive vaccines against hepatitis C virus (HCV) remains one of the main strategies in achieving global elimination of the disease. The effort is focused on the quest for vaccines capable of inducing protective cross-neutralizing humoral and cellular immune responses, which in turn dictate the need for rationally designed cross-genotype vaccine antigens and potent immunoadjuvants systems. This review provides an assessment of the current state of knowledge on immunopotentiating compounds and vaccine delivery systems capable of enhancing HCV antigen-specific immune responses, while focusing on the synergy and interplay of two modalities. Structural, physico-chemical, and biophysical features of these systems are discussed in conjunction with the analysis of their in vivo performance. Extreme genetic diversity of HCV-a well-known hurdle in the development of an HCV vaccine, may also present a challenge in a search for an effective immunoadjuvant, as the effort necessitates systematic and comparative screening of rationally designed antigenic constructs. The progress may be accelerated if the preference is given to well-defined molecular immunoadjuvants with greater formulation flexibility and adaptability, including those capable of spontaneous self-assembly behavior, while maintaining their robust immunopotentiating and delivery capabilities.

Polyphosphazene immunoadjuvants: Historical perspective and recent advances.

The development of successful vaccines has been increasingly reliant on the use of immunoadjuvants - additives, which can enhance and modulate immune responses to vaccine antigens. Immunoadjuvants of the polyphosphazene family encompass synthetic biodegradable macromolecules, which attain in vivo activity via antigen delivery and immunostimulation mechanisms. Over the last decades, the technology has witnessed evolvement of next generation members, expansion to include various antigens and routes of administration, and progression to clinical phase. This was accompanied by gaining important insights into the mechanism of action and the development of a novel class of virus-mimicking nano-assemblies for antigen delivery. The present review evaluates in vitro and in vivo data generated to date in the context of latest advances in understanding the primary function and biophysical behavior of these macromolecules. It also provides an overview of relevant synthetic and characterization methods, macromolecular biodegradation pathways, and polyphosphazene-based multi-component, nanoparticulate, and microfabricated formulations.