Intravenous heterologous prime-boost vaccination activates innate and adaptive immunity to promote tumor regression

PRRSV GP4 subunit vaccine combined with adenovirus heterologous prime-boost immunization strategy induced a significant immune response in mice

BACKGROUND

The porcine reproductive and respiratory syndrome virus (PRRSV) continues to cause widespread infections in the pig industry worldwide. Currently, multiple PRRSV vaccine candidates are in preclinical or clinical trials, and each has different advantages and limitations. Glycoprotein 4 (GP4) is rich in epitopes, which can induce the body to produce neutralizing antibodies, plays a vital role in causing the host immune response, and is a key target for PRRSV vaccine development. In this study, we developed a novel candidate vaccine immunization strategy combining a subunit vaccine with an adenovirus vector vaccine through prokaryotic and eukaryotic systems expressing GP4.

RESULTS

In this study, predictive analysis of PRRSV GP4 antigen structures in two expressed modes, and the results showed good antigenicity. The PRRSV GP4 subunit vaccine, as well as the adenovirus vector-based vaccine, were successfully constructed. In the immunization experiment of mouse models, a heterologous primary-boost immunization strategy was implemented: primary immunization with the GP4 subunit vaccine, and boost immunization was followed by an adenovirus vector vaccine. The safety assessment revealed that all candidate vaccine groups demonstrated good safety profiles. With an indirect enzyme-linked immunosorbent assay (ELISA) and neutralizing antibodies, mice in the combined immunization group developed higher levels of PRRSV-specific antibodies with significantly higher neutralizing antibody titers than mice alone. IgG subtype analysis indicated that the proteome favors the Th2-type immune response, while the adenoviral group favors the Th1-type immune response. The secretion levels of cytokines IL-4, IFN-γ, and TNF-α were significantly higher in the serum of the combined immunization group than in the immune group alone. Moreover, the cellular immune response test results showed that the combined immune group significantly enhanced the splenic lymphocyte proliferation capacity, IFN-γ secretion level, and cytokine transcript level. These findings suggest that the heterologous primary-boost immunization strategy of the PRRSV GP4 subunit vaccine developed here, in combination with the adenovirus vaccine, successfully induced strong humoral and cellular immune responses in mice.

CONCLUSIONS

In this study, the PRRSV GP4 subunit and adenovirus vector vaccine were successfully constructed and induced high levels of PRRSV-specific neutralizing antibody and cellular immune responses in mouse models by a heterologous primary-boost immunization strategy. These results support the clinical development of the PRRSV vaccine and bring new hope for PRRSV prevention and control strategies in the swine industry.

Early spatiotemporal evolution of the immune response elicited by adenovirus serotype 26 vector vaccination in mice

As the first responder to immunological challenges, the innate immune system shapes and regulates the ensuing adaptive immune response. Many clinical studies evaluating the role of innate immunity in initiating vaccine-elicited adaptive immune responses have largely been confined to blood due to the inherent difficulty in acquiring tissue samples. However, the absence of vaccine-site and draining lymph node information limits the understanding of early events induced by vaccination that could potentially shape vaccine-elicited immunity. We, therefore, utilized a mouse model to investigate the spatiotemporal evolution of the immune response within the first 24 hours following intramuscular adenovirus serotype 26 (Ad26) vector vaccination in tissues. We show that the Ad26 vaccine-elicited innate immune response commences by 1 hour and rapidly evolves in tissues and blood within the first 24 hours, as reflected by the detection of cytokines, chemokines, cellular responses, and transcriptomic pathways. Furthermore, serum levels of IL-6, MIG, MIP-1α, MIP-1β, and TNF-α at 6 hours post-vaccination correlated with the frequency of vaccine-elicited memory CD8+ T cell responses evaluated at 60 days post-vaccination in blood and tissues. Taken together, our data suggest that the immune response to Ad26 vector vaccination commences quickly in tissues by 1 hour and that events by as early as 6 hours post-vaccination can shape vaccine-elicited CD8+ T cell responses at later memory time points.IMPORTANCEPrior studies have largely concentrated on innate immune activation in peripheral blood following vaccination. In this study, we report the detailed spatial and temporal innate immune activation in tissues following Ad26 vaccination in mice. We observed rapid innate activation not only in peripheral blood but also in draining lymph nodes and at the site of inoculation. Our findings provide a more detailed picture of the host response to vaccination than previously reported.

Nanovehicles for delivery of antigens and adjuvants as cancer nanovaccines

Cancer vaccines offer a promising strategy for immunotherapy by stimulating the immune system to target and destroy cancer cells. Antigens and adjuvants have been recognized as important components for the preparation of cancer vaccines, with antigens as the keys for immune cells to recognize cancer cells and adjuvants stimulating potent immune effects. Nanovehicles offer great potential advantages for construction of cancer vaccines, including enhanced antigen loading, co-assembly of antigens and adjuvants, targeted delivery, and antigen and adjuvant effects. By leveraging diverse nanovehicles, along with tumor antigens and/or adjuvants, various cancer nanovaccines have been developed, resulting in enhanced immune responses and facilitating the creation of personalized vaccines. This review presents the progress of cancer nanovaccines in clinical trials, systematically summarizing the physicochemical properties and roles of nanovehicles in the delivery of antigens and adjuvants as cancer nanovaccines, including inorganic nanoparticles, polymeric nanovehicles, nanoengineered coordination polymers, lipid nanovehicles, biomimetic nanovehicles, virus-like particles, and self-assembled peptide vehicles. We further discuss challenges in clinical translation and provide insights into future advancements in cancer nanovaccines.

Tailoring mRNA lipid nanoparticles for antifungal vaccines

Vaccination is one of the most effective public health measures for preventing and managing infectious diseases. Despite intensive efforts from the relatively small medical mycology community, developing effective vaccines against invasive fungal infections remains a scientific challenge. This is predominantly due to large antigenic repertoires, complicated life cycles, and the capacity of fungal pathogens to evade the host immune system. Additionally, antifungal vaccines often need to work for at-risk individuals who are immunodeficient. We anticipate that the success of mRNA vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its exploration for various infectious diseases and cancers will usher a new wave of antifungal vaccine research. Herein, we discuss recent advancements and key scientific areas that need to be explored to actualize the development of effective antifungal mRNA vaccines.

Intranasal prime-boost RNA vaccination elicits potent T cell response for lung cancer therapy

The rapid success of RNA vaccines in preventing SARS-CoV-2 has sparked interest in their use for cancer immunotherapy. Although many cancers originate in mucosal tissues, current RNA cancer vaccines are mainly administered non-mucosally. Here, we developed a non-invasive intranasal cancer vaccine utilizing circular RNA encapsulated in lipid nanoparticles to induce localized mucosal immune responses. This strategy elicited potent anti-tumor T cell responses in preclinical lung cancer models while mitigating the systemic adverse effects commonly associated with intravenous RNA vaccination. Specifically, type 1 conventional dendritic cells were indispensable for T cell priming post-vaccination, with both alveolar macrophages and type 1 conventional dendritic cells boosting antigen-specific T cell responses in lung tissues. Moreover, the vaccination facilitated the expansion of both endogenous and adoptive transferred antigen-specific T cells, resulting in robust anti-tumor efficacy. Single-cell RNA sequencing revealed that the vaccination reprograms endogenous T cells, enhancing their cytotoxicity and inducing a memory-like phenotype. Additionally, the intranasal vaccine can modulate the response of CAR-T cells to augment therapeutic efficacy against tumor cells expressing specific tumor-associated antigens. Collectively, the intranasal RNA vaccine strategy represents a novel and promising approach for developing RNA vaccines targeting mucosal malignancies.

Vax-Innate: improving therapeutic cancer vaccines by modulating T cells and the tumour microenvironment

T cells have a critical role in mediating antitumour immunity. The success of immune checkpoint inhibitors (ICIs) for cancer treatment highlights how enhancing endogenous T cell responses can mediate tumour regression. However, mortality remains high for many cancers, especially in the metastatic setting. Based on advances in the genetic characterization of tumours and identification of tumour-specific antigens, individualized therapeutic cancer vaccines targeting mutated tumour antigens (neoantigens) are being developed to generate tumour-specific T cells for improved therapeutic responses. Early clinical trials using individualized neoantigen vaccines for patients with advanced disease had limited clinical efficacy despite demonstrated induction of T cell responses. Therefore, enhancing T cell activity by improving the magnitude, quality and breadth of T cell responses following vaccination is one current goal for improving outcome against metastatic tumours. Another major consideration is how T cells can be further optimized to function within the tumour microenvironment (TME). In this Perspective, we focus on neoantigen vaccines and propose a new approach, termed Vax-Innate, in which vaccination through intravenous delivery or in combination with tumour-targeting immune modulators may improve antitumour efficacy by simultaneously increasing the magnitude, quality and breadth of T cells while transforming the TME into a largely immunostimulatory environment for T cells.

Targeting Siglec-E facilitates tumor vaccine-induced antitumor immunity in renal carcinoma

BACKGROUND

Siglec-E is an immune checkpoint inhibitory molecule. Expression of Siglec-E on the immune cells has been shown to promote tumor regression. This study aimed to develop an adenovirus (Ad) vaccine targeting Siglec-E and carbonic anhydrase IX (CAIX) (Ad-Siglec-E/CAIX) and to evaluate its potential antitumor effects in several preclinical renal cancer models.

METHODS

Ad vaccines encoding Siglec-E or CAIX were developed and evaluated for their therapeutic potential in mouse subcutaneous, lung metastatic, and orthotopic tumor models. The expression of Ad-Siglec-E/CAIX was confirmed via PCR and flow cytometry. Immune responses induced by Ad-Siglec-E/CAIX were assessed in vitro and in vivo using flow cytometry, immunohistochemistry, ELISA, histological analysis, cell proliferation, enzyme-linked immunosorbent spot, cytotoxic T lymphocytes (CTL) killing, and cell depletion assays.

RESULTS

Ad-Siglec-E/CAIX vaccine induced the increase of tumor-infiltrated immune cells, and significantly suppressed the subcutaneous tumor growth of renal carcinoma. Immunization with Ad-Siglec-E/CAIX promoted the induction and maturation of CD11c+ dendritic cells and their subsets, which in turn enhanced tumor-specific CD8+ T cell immune responses, as evidenced by increased CD8+ T cell proliferation and CTL activity. Importantly, the deletion of CD8+ T cells in vivo abolished the antitumor effect of the Ad-Siglec-E/CAIX vaccine, highlighting the essential role of functional CD8+ T cell responses. The potent therapeutic efficacy of the Ad-Siglec-E/CAIX vaccine was also observed in lung metastasis and orthotopic tumor models through tumor-specific CD8+ T cell immune responses.

CONCLUSIONS

Our results indicate that targeting Siglec-E enhances the therapeutic efficacy of Ad-CAIX against renal carcinoma, providing a promising therapeutic option for solid tumors.

Unlocking cancer vaccine potential: What are the key factors?

Cancer is a global health challenge, with changing demographics and lifestyle factors producing an increasing burden worldwide. Screening advancements are enabling earlier diagnoses, but current cancer immunotherapies only induce remission in a small proportion of patients and come at a high cost. Cancer vaccines may offer a solution to these challenges, but they have been mired by poor results in past decades. Greater understanding of tumor biology, coupled with the success of vaccine technologies during the COVID-19 pandemic, has reinvigorated cancer vaccine development. With the first signs of efficacy being reported, cancer vaccines may be beginning to fulfill their potential. Solid tumors, however, present different hurdles than infectious diseases. Combining insights from previous cancer vaccine clinical development and contemporary knowledge of tumor immunology, we ask: who are the 'right' patients, what are the 'right' targets, and which are the 'right' modalities to maximize the chances of cancer vaccine success?

Prognostic and predictive value of pathohistological features in gastric cancer and identification of SLITRK4 as a potential biomarker for gastric cancer

The aim of this study was to develop a quantitative feature-based model from histopathologic images to assess the prognosis of patients with gastric cancer. Whole slide image (WSI) images of H&E-stained histologic specimens of gastric cancer patients from The Cancer Genome Atlas were included and randomly assigned to training and test groups in a 7:3 ratio. A systematic preprocessing approach was employed as well as a non-overlapping segmentation method that combined patch-level prediction with a multi-instance learning approach to integrate features across the slide images. Subjects were categorized into high- or low-risk groups based on the median risk score derived from the model, and the significance of this stratification was assessed using a log-rank test. In addition, combining transcriptomic data from patients and data from other large cohort studies, we further searched for genes associated with pathological features and their prognostic value. A total of 165 gastric cancer patients were included for model training, and a total of 26 features were integrated through multi-instance learning, with each process generating 11 probabilistic features and 2 predictive labeling features. We applied a 10-fold Lasso-Cox regression model to achieve dimensionality reduction of these features. The predictive accuracy of the model was verified using Kaplan-Meyer (KM) curves for stratification with a consistency index of 0.741 for the training set and 0.585 for the test set. Deep learning-based resultant supervised pathohistological features have the potential for superior prognostic stratification of gastric cancer patients, transforming image pixels into an effective and labor-saving tool to optimize the clinical management of gastric cancer patients. Also, SLITRK4 was identified as a prognostic marker for gastric cancer.

Numb and NumbL inhibit melanoma tumor growth by influencing the immune microenvironment

OBJECTIVE

Many investigation have sought to identify therapeutic targets and treatment strategies for skin cutaneous melanoma (SKCM). Numb, an endocytic adaptor protein, is known to act as a tumor suppressor in various human cancers. However, the roles of Numb and its homolog NumbL in immune microenvironment, and their effect on melanoma remain largely unexplored.

METHODS

We analyzed the expression levels of Numb and NumbL, as well as immune signatures of SKCM patients by UCSCXenaShiny v1 database. We also constructed animal model using Numb and NumbL conditional knockout (cKO) mice. Distribution analysis of immune cells in tumors was performed by flow cytometry and pathology staining.

RESULTS

Numb and NumbL were found to be consistently expressed at low levels in SKCM patients. In addition, alterations in tumor immune microenvironment were identified. The CD8+ T, CD19+ B, and NK1.1+ CD49+ cells were decreased in tumors of Numb and NumbL cKO mice, confirming previous bioinformatics analysis of immune signatures. Additionally, we observed CD68+ macrophages to be increased as judged by tumor pathology staining.

CONCLUSION

Numb and NumbL were found to inhibit melanoma cell growth by modulating immune cell activity. These results suggested that Numb and NumbL may be potential therapeutic targets for SKCM patient immunotherapy.

Cancer Vaccines: Recent Insights and Future Directions

The field of cancer immunotherapy has seen incredible advancements in the past decades. mRNA-based cancer vaccines generating de novo T cell responses, particularly against tumor-specific antigens (TSAs), have demonstrated promising clinical outcomes and overcome diverse challenges. Despite the high potential of neoantigens to provide personalized immunotherapies through their tumor specificity and immunogenicity, challenges related to the scarcity of immunogenic neoepitopes have prompted continuous research towards finding new tumor-associated antigens (TAAs) and broader therapeutic frameworks, which may now learn from the genuine successes obtained with neoantigens. As an example, human endogenous retroviruses (HERVs) have emerged as potential alternatives to tumor neoantigens due to their high tumoral expression and ability to elicit both T cell reactivity and B cell responses associated with the efficacy of existing immunotherapies. This review aims to assess the status and limitations of TSA-directed mRNA cancer vaccines and the lessons that can be derived from these and checkpoint inhibitor studies to guide TAA vaccine development. We expect that shared B cell, CD4 and CD8 T cell antigen presentation will be key to stimulate continuous T cell expansion and efficacy for tumors that do not contain pre-existing tertiary lymphoid structures. When these structures are present in highly mutated tumors, the current checkpoint-based immunotherapies show efficacy even in immune privileged sites, and vaccines may hold the key to broaden efficacy to more tumor types and stages.

Early spatiotemporal evolution of the immune response elicited by adenovirus serotype 26 vector vaccination in mice

As the first responder to immunological challenges, the innate immune system shapes and regulates the ensuing adaptive immune response. Many clinical studies evaluating the role of innate immunity in initiating vaccine-elicited adaptive immune responses have largely been confined to blood due to inherent difficulty in acquiring tissue samples. However, the absence of vaccine-site and draining lymph node information limits understanding of early events induced by vaccination that could potentially shape vaccine-elicited immunity. We therefore utilized a mouse model to investigate the spatiotemporal evolution of the immune response within the first 24 hours following intramuscular adenovirus serotype 26 (Ad26) vector vaccination in tissues. We show that the Ad26 vaccine-elicited innate immune response commences by one hour and rapidly evolves in tissues and blood within the first 24 hours as reflected by the detection of cytokines, chemokines, cellular responses, and transcriptomic pathways. Furthermore, serum levels of IL-6, MIG, MIP-1α, and MIP-1β at 6 hours post-vaccination correlated with the frequency of vaccine-elicited memory CD8+ T cell responses evaluated at 60 days post-vaccination in blood and tissues. Taken together, our data suggests that the immune response to Ad26 vector vaccination commences quickly in tissues by one hour and that events by as early as 6 hours post-vaccination can shape vaccine-elicited CD8+ T cell responses at later memory time points.

Novel H-2Db-restricted CD8 epitope derived from mouse MAGE-type antigen P1A mediates antitumor immunity in C57BL/6 mice

BACKGROUND

Melanoma antigen gene (MAGE)-type antigens are promising targets for cancer immunotherapy as they are expressed in cancer cells but not in normal tissues, except for male germline cells. The mouse P1A antigen shares this MAGE-type expression pattern and has been used as a target antigen in preclinical tumor models aiming to induce antitumor CD8+ T-cell responses. However, so far only one MHC I-restricted P1A epitope has been identified. It is presented by H-2Ld in mice of the H-2d genetic background such as DBA/2 and BALB/c. Given the availability of multiple genetically altered strains of mice in the C57BL/6 background, it would be useful to define P1A T-cell epitopes presented by the H-2b haplotype, to facilitate more refined mechanistic studies.

METHODS

We employed a heterologous prime-boost vaccination strategy based on a chimpanzee adenovirus (ChAdOx1) and a modified vaccinia Ankara (MVA) encoding P1A, to induce P1A-specific T-cell responses in C57BL/6 mice. Vaccine-induced responses were measured by intracellular cytokine staining and multiparameter flow cytometry. We mapped the immunogenic CD8 epitope and cloned the cognate T-cell receptor (TCR), which we used for adoptive cell therapy.

RESULTS

ChAdOx1/MVA-P1A vaccination induces a strong P1A-specific CD8+ T-cell response in C57BL/6 mice. This response is directed against a single 9-amino acid peptide with sequence FAVVTTSFL, corresponding to P1A amino acids 43-51. It is presented by H-2Db. P1A vaccination, especially with ChAdOx1 administered intramuscularly and MVA delivered intravenously, protected mice against P1A-expressing EL4 (EL4.P1A) tumor cell challenge. We identified and cloned four TCRs that are specific for the H-2Db-restricted P1A43-51 peptide. T cells transduced with these TCRs recognized EL4.P1A but not MC38.P1A and B16F10.P1A tumor cells, likely due to differences in the proteasome subtypes present in these cells. Adoptive transfer of these T cells in mice bearing EL4.P1A tumors reduced tumor growth and increased survival.

CONCLUSIONS

We identified the first CD8+ T-cell epitope of the MAGE-type P1A tumor antigen presented in the H-2b background. This opens new perspectives for mechanistic studies dissecting MAGE-type specific antitumor immunity, making use of the wealth of genetically altered mouse strains available in the C57BL/6 background. This should facilitate the advancement of specific cancer immunotherapies.

Combination Immunotherapy with Vaccine and Oncolytic HSV Virotherapy Is Time Dependent

Oncolytic virotherapy or immunovirotherapy is a strategy that utilizes viruses to selectively infect and kill tumor cells while also stimulating an immune response against the tumor. Early clinical trials in both pediatric and adult patients using oncolytic herpes simplex viruses (oHSV) have demonstrated safety and promising efficacy; however, combinatorial strategies designed to enhance oncolysis while also promoting durable T-cell responses for sustaining disease remission are likely required. We hypothesized that combining the direct tumor cell killing and innate immune stimulation by oHSV with a vaccine that promotes T cell-mediated immunity may lead to more durable tumor regression. To this end, we investigated the preclinical efficacy and potential synergy of combining oHSV with a self-assembling nanoparticle vaccine codelivering peptide antigens and Toll-like receptor 7 and 8 agonists (referred to as SNAPvax),which induces robust tumor-specific T-cell immunity. We then assessed how timing of the treatments (i.e., vaccine before or after oHSV) impacts T-cell responses, viral replication, and preclinical efficacy. The sequence of treatments was critical, as survival was significantly enhanced when the SNAPvax vaccine was given prior to oHSV. Increased clinical efficacy was associated with reduced tumor volume and increases in virus replication and tumor antigen-specific CD8+ T cells. These findings substantiate the criticality of combination immunotherapy timing and provide preclinical support for combining SNAPvax with oHSV as a promising treatment approach for both pediatric and adult tumors.

Mannan-Decorated Lipid Calcium Phosphate Nanoparticle Vaccine Increased the Antitumor Immune Response by Modulating the Tumor Microenvironment

With the rapid development of tumor immunotherapy, nanoparticle vaccines have attracted much attention as potential therapeutic strategies. A systematic review and analysis must be carried out to investigate the effect of mannose modification on the immune response to nanoparticles in regulating the tumor microenvironment, as well as to explore its potential clinical application in tumor therapy. Despite the potential advantages of nanoparticle vaccines in immunotherapy, achieving an effective immune response in the tumor microenvironment remains a challenge. Tumor immune escape and the overexpression of immunosuppressive factors limit its clinical application. Therefore, our review explored how to intervene in the immunosuppressive mechanism in the tumor microenvironment through the use of mannan-decorated lipid calcium phosphate nanoparticle vaccines to improve the efficacy of immunotherapy in patients with tumors and to provide new ideas and strategies for the field of tumor therapy.

Resident memory T cells and cancer

Tissue-resident memory T (TRM) cells positively correlate with cancer survival, but the anti-tumor mechanisms underlying this relationship are not understood. This review reconciles these observations, summarizing concepts of T cell immunosurveillance, fundamental TRM cell biology, and clinical observations on the role of TRM cells in cancer and immunotherapy outcomes. We also discuss emerging strategies that utilize TRM-phenotype cells for patient diagnostics, staging, and therapy. Current challenges are highlighted, including a lack of standardized T cell nomenclature and our limited understanding of relationships between T cell markers and underlying tumor biology. Existing findings are integrated into a summary of the field while emphasizing opportunities for future research.

Next-generation cancer vaccines and emerging immunotherapy combinations

Therapeutic cancer vaccines have been a subject of research for several decades as potential new weapons to tackle malignancies. Their goal is to induce a long-lasting and efficient antitumour-directed immune response, capable of mediating tumour regression, preventing tumour progression, and eradicating minimal residual disease, while avoiding major adverse effects. Development of new vaccine technologies and antigen prediction methods has led to significant improvements in cancer vaccine efficacy. However, for their successful clinical application, certain obstacles still need to be overcome, especially tumour-mediated immunosuppression and escape mechanisms. In this review, we introduce therapeutic cancer vaccines and subsequently discuss combination approaches of next-generation cancer vaccines and existing immunotherapies, particularly immune checkpoint inhibitors (ICIs) and adoptive cell transfer/cell-based immunotherapies.

Long Prime-Boost Interval and Heightened Anti-GD2 Antibody Response to Carbohydrate Cancer Vaccine

The carbohydrate ganglioside GD2/GD3 cancer vaccine adjuvanted by β-glucan stimulates anti-GD2 IgG1 antibodies that strongly correlate with improved progression-free survival (PFS) and overall survival (OS) among patients with high-risk neuroblastoma. Thirty-two patients who relapsed on the vaccine (first enrollment) were re-treated on the same vaccine protocol (re-enrollment). Titers during the first enrollment peaked by week 32 at 751 ± 270 ng/mL, which plateaued despite vaccine boosts at 1.2-4.5 month intervals. After a median wash-out interval of 16.1 months from the last vaccine dose during the first enrollment to the first vaccine dose during re-enrollment, the anti-GD2 IgG1 antibody rose to a peak of 4066 ± 813 ng/mL by week 3 following re-enrollment (p < 0.0001 by the Wilcoxon matched-pairs signed-rank test). Yet, these peaks dropped sharply and continually despite repeated boosts at 1.2-4.5 month intervals, before leveling off by week 20 to the first enrollment peak levels. Despite higher antibody titers, patients experienced no pain or neuropathic side effects, which were typically associated with immunotherapy using monoclonal anti-GD2 antibodies. By the Kaplan-Meier method, PFS was estimated to be 51%, and OS was 81%. The association between IgG1 titer during re-enrollment and β-glucan receptor dectin-1 SNP rs3901533 was significant (p = 0.01). A longer prime-boost interval could significantly improve antibody responses in patients treated with ganglioside conjugate cancer vaccines.

Design and Evaluation of Synthetic Delivery Formulations for Peptide-Based Cancer Vaccines

With the recent advances in neoantigen identification, peptide-based cancer vaccines offer substantial potential in the field of immunotherapy. However, rapid clearance, low immunogenicity, and insufficient antigen-presenting cell (APC) uptake limit the efficacy of peptide-based cancer vaccines. This review explores the barriers hindering vaccine efficiency, highlights recent advancements in synthetic delivery systems, and features strategies for the key delivery steps of lymph node (LN) drainage, APC delivery, cross-presentation strategies, and adjuvant incorporation. This paper also discusses the design of preclinical studies evaluating vaccine efficiency, including vaccine administration routes and murine tumor models.