Vaccine adjuvant materials for cancer immunotherapy and control of infectious disease

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.

Revolutionizing Cancer Treatment: Recent Advances in Immunotherapy

Cancer immunotherapy has emerged as a transformative approach in oncology, utilizing the body's immune system to specifically target and destroy malignant cells. This review explores the scope and impact of various immunotherapeutic strategies, including monoclonal antibodies, chimeric antigen receptor (CAR)-T cell therapy, checkpoint inhibitors, cytokine therapy, and therapeutic vaccines. Monoclonal antibodies, such as Rituximab and Trastuzumab, have revolutionized treatment paradigms for lymphoma and breast cancer by offering targeted interventions that reduce off-target effects. CAR-T cell therapy presents a potentially curative option for refractory hematologic malignancies, although challenges remain in effectively treating solid tumors. Checkpoint inhibitors have redefined the management of cancers like melanoma and lung cancer; however, managing immune-related adverse events and ensuring durable responses are critical areas of focus. Cytokine therapy continues to play a vital role in modulating the immune response, with advancements in cytokine engineering improving specificity and reducing systemic toxicity. Therapeutic vaccines, particularly mRNA-based vaccines, represent a frontier in personalized cancer treatment, aiming to generate robust, long-lasting immune responses against tumor-specific antigens. Despite these advancements, the field faces significant challenges, including immune resistance, tumor heterogeneity, and the immunosuppressive tumor microenvironment. Future research should address these obstacles through emerging technologies, such as next-generation antibodies, Clustered Regularly Interspaced Short Palindromic Repeat (CRISPR)-based gene editing, and AI-driven drug discovery. By integrating these novel approaches, cancer immunotherapy holds the promise of offering more durable, less toxic, and highly personalized treatment options, ultimately improving patient outcomes and survival rates.

Lung cancer vaccination from concept to reality: A critical review of clinical trials and latest advances

Lung cancer is a highly lethal malignancy that poses a significant burden on public health worldwide. There have been numerous therapeutic approaches, among which cancer vaccines have emerged as a promising approach to harnessing the patient's immune system to induce long-lasting anti-tumor immunity. The current study aims to provide an overview of cancer vaccination in the context of lung cancer to establish a clearer landscape for lung cancer treatment. To provide a comprehensive review, we not only gathered the published studies of lung cancer vaccination and discussed their effectiveness and safety profile but also analyzed all the relevant clinical trials registered on www.clinicaltrials.gov until March 2024. We demonstrated all utilized vaccine platforms along with having a glance at novel technologies such as mRNA vaccines. The present review discussed the challenges and shortcomings of lung cancer vaccination, as well as the way they could be managed to pave the way for reaching the most optimized vaccine formulation.

Vaccine adjuvants: current status, research and development, licensing, and future opportunities

Vaccines represent one of the most significant inventions in human history and have revolutionized global health. Generally, a vaccine functions by triggering the innate immune response and stimulating antigen-presenting cells, leading to a defensive adaptive immune response against a specific pathogen's antigen. As a key element, adjuvants are chemical materials often employed as additives to increase a vaccine's efficacy and immunogenicity. For over 90 years, adjuvants have been essential components in many human vaccines, improving their efficacy by enhancing, modulating, and prolonging the immune response. Here, we provide a timely and comprehensive review of the historical development and the current status of adjuvants, covering their classification, mechanisms of action, and roles in different vaccines. Additionally, we perform systematic analysis of the current licensing processes and highlights notable examples from clinical trials involving vaccine adjuvants. Looking ahead, we anticipate future trends in the field, including the development of new adjuvant formulations, the creation of innovative adjuvants, and their integration into the broader scope of systems vaccinology and vaccine delivery. The article posits that a deeper understanding of biochemistry, materials science, and vaccine immunology is crucial for advancing vaccine technology. Such advancements are expected to lead to the future development of more effective vaccines, capable of combating emerging infectious diseases and enhancing public health.

Bestatin, A Pluripotent Immunomodulatory Small Molecule, Drives Robust and Long-Lasting Immune Responses as an Adjuvant in Viral Vaccines

An inactivated whole-virus vaccine is currently used to prevent foot-and-mouth disease (FMD). Although this vaccine is effective, it offers short-term immunity that requires regular booster immunizations and has several side effects, including local reactions at the vaccination site. To address these limitations, herein, we evaluated the efficacy of bestatin as a novel small molecule adjuvant for inactivated FMD vaccines. Our findings showed that the FMD vaccine formulated with bestatin enhanced early, intermediate-, and particularly long-term immunity in experimental animals (mice) and target animals (pigs). Furthermore, cytokines (interferon (IFN)α, IFNβ, IFNγ, and interleukin (IL)-29), retinoic acid-inducible gene (RIG)-I, and T-cell and B-cell core receptors (cluster of differentiation (CD)28, CD19, CD21, and CD81) markedly increased in the group that received the FMD vaccine adjuvanted with bestatin in pigs compared with the control. These results indicate the significant potential of bestatin to improve the efficacy of inactivated FMD vaccines in terms of immunomodulatory function for the simultaneous induction of potent cellular and humoral immune response and a long-lasting memory response.

Combining in situ vaccination and immunogenic apoptosis to treat cancer

Immunization approaches are designed to stimulate the immune system and eliminate the tumor. Studies indicate that cancer immunization combined with certain chemotherapeutics and immunostimulatory agents can improve outcomes. Chemotherapeutics-based immunogenic cell death makes the tumor more recognizable by the immune system. In situ vaccination (ISV) utilizes established tumors as antigen sources and directly applies an immune adjuvant to the tumor to reverse a cold tumor microenvironment to a hot one. Immunogenic cell death and ISV highlight for the immune system the tumor antigens that are recognizable by immune cells and support a T-cell attack of the tumor cells. This review presents the concept of immunogenic apoptosis and ISV as a powerful platform for cancer immunization.

Evaluation of Immune Modulation by β-1,3; 1,6 D-Glucan Derived from Ganoderma lucidum in Healthy Adult Volunteers, A Randomized Controlled Trial

Fungi-derived β-glucan, a type of glucopolysaccharide, has been shown to possess immune-modulatory properties in clinical settings. Studies have indicated that β-glucan derived from Ganoderma lucidum (commonly known as Reishi) holds particular promise in this regard, both in laboratory and in vivo settings. To further investigate the efficacy and safety of Reishi β-glucan in human subjects, a randomized, double-blinded, placebo-controlled clinical trial was conducted among healthy adult volunteers aged 18 to 55. Participants were instructed to self-administer the interventions or placebos on a daily basis for 84 days, with bloodwork assessments conducted at the beginning and end of the study. The results of the trial showed that subjects in the intervention group, who received Reishi β-glucan, exhibited a significant enhancement in various immune cell populations, including CD3+, CD4+, CD8+ T-lymphocytes, as well as an improvement in the CD4/CD8 ratio and natural killer cell counts when compared to the placebo group. Additionally, a statistically significant difference was observed in serum immunoglobulin A levels and natural killer cell cytotoxicity between the intervention and placebo groups. Notably, the intervention was found to be safe and well tolerated, with no statistically significant changes observed in markers of kidney or liver function in either group. Overall, the study provides evidence for the ability of Reishi β-glucan to modulate immune responses in healthy adults, thereby potentially bolstering their defense against opportunistic infections.

Advances in Infectious Disease Vaccine Adjuvants

Vaccines are one of the most significant medical interventions in the fight against infectious diseases. Since their discovery by Edward Jenner in 1796, vaccines have reduced the worldwide transmission to eradication levels of infectious diseases, including smallpox, diphtheria, hepatitis, malaria, and influenza. However, the complexity of developing safe and effective vaccines remains a barrier for combating many more infectious diseases. Immune stimulants (or adjuvants) are an indispensable factor in vaccine development, especially for inactivated and subunit-based vaccines due to their decreased immunogenicity compared to whole pathogen vaccines. Adjuvants are widely diverse in structure; however, their overall function in vaccine constructs is the same: to enhance and/or prolong an immunological response. The potential for adverse effects as a result of adjuvant use, though, must be acknowledged and carefully managed. Understanding the specific mechanisms of adjuvant efficacy and safety is a key prerequisite for adjuvant use in vaccination. Therefore, rigorous pre-clinical and clinical research into adjuvant development is essential. Overall, the incorporation of adjuvants allows for greater opportunities in advancing vaccine development and the importance of immune stimulants drives the emergence of novel and more effective adjuvants. This article highlights recent advances in vaccine adjuvant development and provides detailed data from pre-clinical and clinical studies specific to infectious diseases. Future perspectives into vaccine adjuvant development are also highlighted.

Neoantigens and their potential applications in tumor immunotherapy

The incidence of malignant tumors is increasing, the majority of which are associated with high morbidity and mortality rates worldwide. The traditional treatment method for malignant tumors is surgery, coupled with radiotherapy or chemotherapy. However, these therapeutic strategies are frequently accompanied with adverse side effects. Over recent decades, tumor immunotherapy shown promise in demonstrating notable efficacy for the treatment of cancer. With the development of sequencing technology and bioinformatics algorithms, neoantigens have become compelling targets for cancer immunotherapy due to high levels of immunogenicity. In addition, neoantigen-based vaccines have demonstrated potential for cancer therapy, primarily by augmenting T-cell responses. Neoantigens have also been shown to be effective in immune checkpoint blockade therapy. Therefore, neoantigens may serve to be predictive biomarkers and synergistic treatment targets in cancer immunotherapy. The aim of the present review was to provide an overview of the recent progress in the classification, screening and clinical application of neoantigens for cancer therapy.

Novel adjuvants enhance immune responses elicited by a replication-defective human cytomegalovirus vaccine in nonhuman primates

Adjuvants have long been explored to enhance vaccine efficacy. Current adjuvants approved for human vaccines are mostly studied for their ability to improve antibody responses. There remains a need for development of novel adjuvants, especially those able to enhance cell-mediated immunity (CMI). In this preclinical study we assessed the effect of two novel adjuvants, a delta inulin microparticle Advax formulated with or without a toll-like receptor 9 (TLR9) agonist CpG oligonucleotide, and a Merck & Co., Inc., Kenilworth, NJ, USA proprietary lipid nanoparticle (LNP), on immune responses elicited by V160, an experimental replication-defective human cytomegalovirus vaccine. Adult rhesus macaques were immunized with a low dose of V160 (10 units) either alone or in combination with the adjuvants as compared to those immunized with a high dose of V160 alone (100 units). While neither adjuvant conferred a significant benefit to vaccine-elicited humoral immune responses at the dose tested, both enhanced cellular immune responses to V160, where Advax promoted both CD4⁺ and CD8⁺ T cells and LNP predominantly impacted the CD4⁺ T cell response. Transcriptome analyses of peripheral blood samples demonstrated different modes of action for these adjuvants. One day post vaccination, LNP induced upregulation of a large number of genes involved in the innate immune response similar to those triggered by viral infection. In contrast, Advax did not activate any known inflammatory pathways and did not significantly impact gene expression pattern until day 7 post administration, suggesting a unique, non-inflammatory mechanism. These data warrant further exploration of Advax and LNP as adjuvants in clinical trials for vaccines desiring to elicit both humoral and T cell responses.

Dairy-Derived and Egg White Proteins in Enhancing Immune System Against COVID-19

Coronavirus disease (COVID-19) is a global health challenge, caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) triggers a plethora of respiratory disturbances and even multiple organs failure that can be fatal. Nutritional intervention is one of the key components toward to a proper management of COVID-19 patients, especially in those requiring medication, and should thus be considered the first-line treatment. Immuno-modulation and -stimulation are currently being explored in COVID-19 management and are gaining interest by food and pharmaceutical industries. Various dietary combinations, bioactive components, nutrients and fortified foods have been reported to modulate inflammation during disease progression. Dietary combinations of dairy-derived products and eggs are gaining an increasing attention given the huge immunomodulatory and anti-inflammatory properties attributed to some of their chemical constituents. Eggs are complex dietary components containing many essential nutrients and bioactive compounds as well as a high-quality proteins. Similarly, yogurts can replenish beneficial bacteria and contains macronutrients capable of stimulating immunity by enhancing cell immunity, reducing oxidative stress, neutralizing inflammation and regulating the intestinal barriers and gut microbiome. Thus, this review highlights the impact of nutritional intervention on COVID-19 management, focusing on the immunomodulatory and inflammatory effects of immune-enhancing nutrients.

Cancer Vaccines: Adjuvant Potency, Importance of Age, Lifestyle, and Treatments

Although the discovery and characterization of multiple tumor antigens have sparked the development of many antigen/derived cancer vaccines, many are poorly immunogenic and thus, lack clinical efficacy. Adjuvants are therefore incorporated into vaccine formulations to trigger strong and long-lasting immune responses. Adjuvants have generally been classified into two categories: those that ‘depot’ antigens (e.g. mineral salts such as aluminum hydroxide, emulsions, liposomes) and those that act as immunostimulants (Toll Like Receptor agonists, saponins, cytokines). In addition, several novel technologies using vector-based delivery of antigens have been used. Unfortunately, the immune system declines with age, a phenomenon known as immunosenescence, and this is characterized by functional changes in both innate and adaptive cellular immunity systems as well as in lymph node architecture. While many of the immune functions decline over time, others paradoxically increase. Indeed, aging is known to be associated with a low level of chronic inflammation—inflamm-aging. Given that the median age of cancer diagnosis is 66 years and that immunotherapeutic interventions such as cancer vaccines are currently given in combination with or after other forms of treatments which themselves have immune-modulating potential such as surgery, chemotherapy and radiotherapy, the choice of adjuvants requires careful consideration in order to achieve the maximum immune response in a compromised environment. In addition, more clinical trials need to be performed to carefully assess how less conventional form of immune adjuvants, such as exercise, diet and psychological care which have all be shown to influence immune responses can be incorporated to improve the efficacy of cancer vaccines. In this review, adjuvants will be discussed with respect to the above-mentioned important elements.

Abscopal Effect Following Radiation Therapy in Cancer Patients: A New Look from the Immunological Point of View

Abscopal effect, a radiobiology term meaning “away from target”, was practically unheard of just ten years ago. This effect describes the elimination and cure of a non-treated tumor when another part of the body is irradiated. Successful treatment of cancer in patients with multiple metastatic foci has sporadically been reported. Abscopal effect after radiotherapy has been introduced as the key factor which induced an anticancer response in these metastatic lesions. Moreover, not receiving chemotherapy is reported to have a role in cancer regression after radiotherapy. Given this consideration, it can be hypothesized that standard radiotherapy doses, which usually classified as high-dose, may cause cancer cells to expose or release their sequestered antigens that had been previously masked. Furthermore, radiotherapy can decrease the suppressive effect of regulatory T cells which usually down modulate immune responses against cancers. Moreover, some data show that low dose total-body irradiation (TBI) alone (without standard localized high dose radiotherapy) may cause suppression of distant metastasis of tumor cells. Induction of a “whole body abscopal effect” can be involved in suppression of distant metastasis. Here we discuss whether cancer treatments could be more successful if immune system is boosted, not destroyed by the treatments such as chemotherapy

Encapsulation of Poly I:C and the natural phosphodiester CpG ODN enhanced the efficacy of a hyaluronic acid-modified cationic lipid-PLGA hybrid nanoparticle vaccine in TC-1-grafted tumors

FDA approval of CpG oligodeoxynucleotide (CpG ODN) adjuvants for a human hepatitis B virus vaccine has been delayed until late 2017 because of concerns regarding the severe side effects, which may be attributed to the high dosage and systemic diffusion of this proinflammatory material. Considering that PLGA could provide shelter to resist nucleases in tissue and that cationic lipids could confine anionic oligonucleotides in the nanoparticles via electrostatic attraction to avoid systemic diffusion, we encapsulated a natural phosphodiester or the expensive phosphorothioate CpG ODNs in our previously reported hyaluronic acid-modified cationic lipid-PLGA hybrid nanoparticles and evaluated vaccine efficacy in a TC-1-grafted mouse model. Our results showed that together with Poly I:C, CpG ODN could promote the maturation of bone marrow-derived dendritic cells and the cross-presentation of exogenous antigens in vitro. For the coencapsulation with Poly I:C, in vivo studies showed that adjuvant effects on the vaccine efficacy of tumor depression, immune cell activation, and memory T-cell elevation of phosphodiester CpG ODNs were comparable to those of the phosphorothioate CpG ODNs at a low concentration (5 µg/dose). In conclusion, the combination of oligonucleotide adjuvants and synthetic particulate systems not only potentiated the immunogenicity of these nanoparticles but also made these adjuvants safer and more economical, which may be helpful for their wide application.

Recent advances in cancer immunology and immunology-based anticancer therapies

Cancer immunotherapies offer promise for cure of cancer with specificity and minimal toxicity. Recent developments in cancer immunology have led to the better understanding of role of immune regulatory mechanisms in cancer. There is rapid progress in this field in the last few years. Several clinical studies report the efficacy of immunotherapies for treating cancer. The immunology-based anticancer therapies have shown better safety profiles in clinic as compared to other chemotherapeutic agents, thus increasing interest in this area. This review summarizes recent advances in cancer immunology and discusses tumor microenvironment and immunology-based anticancer therapies, including vaccines and therapies targeting immune checkpoints.

Immunotherapy as an Option for Cancer Treatment

The progress in melanoma immunotherapy highlights the importance of immunotherapy for cancer treatment. Although the concept of immunotherapy emerged in the beginning of the twentieth century, the end of the century signaled the start of modern immunotherapy, which has recently allowed a staggering progress in the field of cancer immunotherapy. Currently, there is a wide variety of immunotherapeutic approaches and critical improvements are continually being made. Among different immunotherapeutic strategies, therapies based on the blockade of immune checkpoint molecules have shown unparalleled efficacy in late-stage cancer patients. Pre-clinical research using ex vivo and in vivo approaches demonstrates the promise of numerous novel strategies for the immunotherapy of cancer.

The Novel Toll-Like Receptor 2 Agonist SUP3 Enhances Antigen Presentation and T Cell Activation by Dendritic Cells

Dendritic cells (DCs) are highly specialized antigen-presenting cells that play crucial roles in innate and adaptive immunity. Previous studies suggested that Toll-like receptor (TLR) agonists could be used as potential adjuvants, as activation of TLRs can boost DC-induced immune responses. TLR2 agonists have been shown to enhance DC-mediated immune responses. However, classical TLR2 agonists such as Pam3CSK4 are not stable enough in vivo, which limits their clinical applications. In this study, a novel structurally stable TLR2 agonist named SUP3 was designed. Functional analysis showed that SUP3 induced much stronger antitumor response than Pam3CSK4 by promoting cytotoxic T lymphocytes activation in vivo. This effect was achieved through the following mechanisms: SUP3 strongly enhanced the ability of antigen cross-presentation by DCs and subsequent T cell activation. SUP3 upregulated the expression of costimulatory molecules on DCs and increased antigen deposition in draining lymph nodes. More interestingly, SUP3 induced less amount of pro-inflammatory cytokine production in vivo compared to other TLR agonists such as lipopolysaccharide. Taken together, SUP3 could serve as a novel promising immune adjuvant in vaccine development and immune modulations.

Potentiation of human papilloma vaccine candidate using naloxone/alum mixture as an adjuvant: increasing immunogenicity of HPV-16E7d vaccine

OBJECTIVES

Many types of human papillomaviruses (HPVs) have been identified, with some leading to cancer and others to skin lesions such as anogenital warts. Studies have demonstrated an association between oncogenic HPV and cervical cancer and many researchers have focused on therapeutic vaccines development. At present, the modulatory effect of opioids on the innate and acquired immune system is characterized. Antagonists of opioid receptors such as naloxone (NLX) can contribute to the shifting Th2 response toward Th1. Herein; we studied the adjuvant activity of NLX/Alum mixture for improvement of the immunogenicity of HPV-16E7d vaccine.

MATERIALS AND METHODS

The mice were administered different regimens of vaccine; E7d, E7d-NLX, E7d-Alum, E7d-NLX-Alum, NLX, alum and PBS via subcutaneous route for three times with two weeks interval. Two weeks after the last immunization, the sera were assessed for total antibody, IgG1 and IgG2a with an optimized ELISA method. The splenocytes culture supernatant was analyzed by ELISA for the presence of IL-4, IFN-γ and IL-17 cytokines and lymphocyte proliferation was evaluated with Brdu method.

RESULTS

Immunization of mice with HPV-16 E7d vaccine formulated in NLX/Alum mixture significantly increased lymphocyte proliferation and Th1 and Th17 cytokines responses compared to other experimental groups. Analysis of humoral immune responses revealed that administration of vaccine with NLX/Alum mixture significantly increased specific IgG responses and also isotypes compared to control groups.

CONCLUSION

NLX/Alum mixture as an adjuvant could improve cellular and humoral immune responses and the adjuvant maybe useful for HPV vaccines model for further studies in human clinical trial.

Therapeutic Cancer Vaccines

Cancer is one of the major leading death causes of diseases. Prevention and treatment of cancer is an important way to decrease the incidence of tumorigenesis and prolong patients' lives. Subversive achievements on cancer immunotherapy have recently been paid much attention after many failures in basic and clinical researches. Based on deep analysis of genomics and proteomics of tumor antigens, a variety of cancer vaccines targeting tumor antigens have been tested in preclinical and human clinical trials. Many therapeutic cancer vaccines alone or combination with other conventional treatments for cancer obtained spectacular efficacy, indicating the tremendously potential application in clinic. With the illustration of underlying mechanisms of cancer immune regulation, valid, controllable, and persistent cancer vaccines will play important roles in cancer treatment, survival extension and relapse and cancer prevention. This chapter mainly summarizes the recent progresses and developments on cancer vaccine research and clinical application, thus exploring the existing obstacles in cancer vaccine research and promoting the efficacy of cancer vaccine.

Innate Immune Memory: The Latest Frontier of Adjuvanticity

Recent findings in the field of immune memory have demonstrated that B and T cell mediated immunity following infections are enhanced by the so-called trained immunity. This effect has been most extensively investigated for the tuberculosis vaccine strain Bacillus Calmette-Guérin (BCG). Epidemiological studies suggest that this vaccine is associated with a substantial reduction in overall child mortality that cannot be solely explained by prevention of the target disease but that it seems to rely on inducing resistance to other infections. Upon infection or vaccination, monocytes/macrophages can be functionally reprogrammed so as to display an enhanced defensive response against unrelated infections. Epigenetic modifications seem to play a key role in the induction of this “innate memory.” These findings are revolutionising our knowledge of the immune system, introducing the concept of memory also for mammalian innate immunity. Thus, vaccines are likely to nonspecifically affect the overall immunological status of individuals in a clinically relevant manner. As a consequence, future vaccine strategies ought to take into account the contribution of innate memory through appropriate design of formulations and administration scheduling.

Vaccines, Adjuvants, and Dendritic Cell Activators--Current Status and Future Challenges

Cancer vaccines offer a low-toxicity approach to induce anticancer immune responses. They have shown promise for clinical benefit with one cancer vaccine approved in the United States for advanced prostate cancer. As other immune therapies are now clearly effective for treatment of advanced cancers of many histologies, there is renewed enthusiasm for optimizing cancer vaccines for use to prevent recurrence in early-stage cancers and/or to combine with other immune therapies for therapy of advanced cancers. Future advancements in vaccine therapy will involve the identification and selection of effective antigen formulations, optimization of adjuvants, dendritic cell (DC) activation, and combination therapies. In this summary we present the current practice, the broad collection of challenges, and the promising future directions of vaccine therapy for cancer.