Search Results (578)

Vaccination is the most effective method to counteract infectious diseases in farmed fish. It secures aquaculture production and safeguards the wild stock and aquatic ecosystem from catastrophic contagious diseases. In vaccine development, recombinant subunit vaccines are favorable candidates since they can be economically produced in large quantities without growing many pathogens, as in inactivated or attenuated vaccine production. However, recombinant subunit vaccines are often weak or deficient in immunogenicity, resulting in inadequate defenses against infections. Technologies that can increase the immunogenicity of recombinant subunit vaccines are in desperate need. Enhanced green fluorescence protein (EGFP) has a low antigenicity and is susceptible to folding changes and losing fluorescence after fusing with other proteins. Using these valuable features of EGFP, we comprehend two amphipathic alpha-helical peptides, AH1 and AH3, derived from Hepatitis C virus and Influenza A virus, respectively, that can induce high immune responses of their fused EGFP in fish without affecting their folding. AH3-EGFP has the most elevated cell binding, significantly 62% and 36% higher than EGFP and AH1-EGFP, respectively. Immunizations with AH1-EGFP or AH3-EGFP significantly induced higher anti-EGFP antibody levels 300–500-fold higher than EGFP immunization after the boost injection in rainbow trout. Our results suggest that AH1 and AH3 effectively increase the immunogenicity of EGFP without influencing its structure. Further validation of their value in other recombinant proteins is necessary to demonstrate their broader utility in enhancing the immunogenicity of subunit vaccines. We also suggest that EGFP and its variants are promising candidates for initially screening proper immunogenicity-enhancing peptides or proteins to advance recombinant subunit vaccine development. Full article

Avian influenza A viruses (IAVs) pose a persistent threat to the poultry industry, causing substantial economic losses. Although traditional vaccines have helped reduce the disease burden, they typically rely on multivalent antigens, emphasize humoral immunity, and require intensive production. This study aimed to establish a genetically matched host–cell system to evaluate antigen-specific immune responses and identify conserved CD8+ T cell epitopes in avian influenza viruses. To this end, we developed an MHC class I genotype (B21)-matched host (Lohmann VALO SPF chicken) and cell vector (DF-1 cell line) model. DF-1 cells were engineered to express the hemagglutinin (HA) gene of clade 2.3.4.4b H5N1 either transiently or stably, and to stably express the matrix 1 (M1) and nucleoprotein (NP) genes of A/chicken/South Korea/SL20/2020 (H9N2, Y280-lineage). Following prime-boost immunization with HA-expressing DF-1 cells, only live cells induced strong hemagglutination inhibition (HI) and virus-neutralizing (VN) antibody titers in haplotype-matched chickens. Importantly, immunization with DF-1 cells transiently expressing NP induced stronger IFN-γ production than those expressing M1, demonstrating the platform’s potential for differentiating antigen-specific cellular responses. CD8+ T cell epitope mapping by mass spectrometry identified one distinct MHC class I-bound peptide from each of the HA-, M1-, and NP-expressing DF-1 cell lines. Notably, the identified HA epitope was conserved in 97.6% of H5-subtype IAVs, and the NP epitope in 98.5% of pan-subtype IAVs. These findings highlight the platform’s utility for antigen dissection and rational vaccine design. While limited by MHC compatibility, this approach enables identification of naturally presented epitopes and provides insight into conserved, functionally constrained viral targets. Full article

Background: Bovine babesiosis, caused by the tick-borne apicomplexan parasite Babesia spp., is an economically significant disease that threatens the cattle industry worldwide. Babesia bovis is the most pathogenic species, leading to high morbidity and mortality in infected animals. One promising approach to vaccination against bovine babesiosis involves the use of multiple protective antigens, offering advantages over traditional live-attenuated vaccines. Tools such as immunobioinformatics and reverse vaccinology have facilitated the identification of novel antigens. Enolase, a “moonlighting” enzyme of the glycolytic pathway with demonstrated vaccine potential in other pathogens, has not yet been studied in B. bovis. Methods: In this study, the enolase gene from two B. bovis isolates was successfully identified and sequenced. The gene, consisting of 1366 base pairs, encodes a predicted protein of 438 amino acids. Its expression in intraerythrocytic parasites was confirmed by RT-PCR. Two peptides containing predicted B-cell epitopes were synthesized and used to immunize rabbits. Hyperimmune sera were then analyzed by ELISA, confocal microscopy, Western blot, and an in vitro neutralization assay. Results: The hyperimmune sera showed high antibody titers, reaching up to 1:256,000. Specific antibodies recognized intraerythrocytic merozoites by confocal microscopy and bound to a ~47 kDa protein in erythrocytic cultures of B. bovis as detected by Western blot. In the neutralization assay, antibodies raised against peptide 1 had no observable effect, whereas those targeting peptide 2 significantly reduced parasitemia by 71.99%. Conclusions: These results suggest that B. bovis enolase contains B-cell epitopes capable of inducing neutralizing antibodies and may play a role in parasite–host interactions. Enolase is therefore a promising candidate for further exploration as a vaccine antigen. Nonetheless, additional experimental studies are needed to fully elucidate its biological function and validate its vaccine potential. Full article

Gastric cancer (GC) remains a major cause of cancer-related mortality worldwide, with human epidermal growth factor receptor 2 (HER2)-positive disease representing a clinically relevant subset. Trastuzumab combined with chemotherapy is the standard first-line treatment in advanced settings, following the landmark ToGA trial. However, resistance to trastuzumab has emerged as a significant limitation, prompting the need for more effective second-line therapies. Trastuzumab deruxtecan, a novel antibody–drug conjugate (ADC) composed of trastuzumab linked to a cytotoxic payload, has demonstrated promising efficacy in trastuzumab-refractory, HER2-positive GC, including cases with heterogeneous HER2 expression. Other HER2-targeted ADCs are also under investigation as potential alternatives. In addition, strategies to overcome resistance include HER2-specific immune-based therapies, such as peptide vaccines and chimeric antigen receptor T cell therapies, as well as antibodies targeting distinct HER2 domains or downstream signaling pathways like PI3K/AKT. These emerging approaches aim to improve efficacy in both HER2-high and HER2-low GC. As HER2-targeted treatments evolve, addressing resistance mechanisms and optimizing therapy for broader patient populations is critical. This review discusses current and emerging HER2-directed strategies in GC, focusing on trastuzumab deruxtecan and beyond, and outlines future directions to improve outcomes for patients with HER2-positive GC across all clinical settings. Full article

Monkeypox virus (MPXV) has caused 148,892 confirmed cases and 341 deaths from 137 countries worldwide, as reported by the World Health Organization (WHO), highlighting the urgent need for effective vaccines to prevent the spread of MPXV. Traditional vaccine development is low-throughput, expensive, time consuming, and susceptible to reversion to virulence. Alternatively, a reverse vaccinology approach offers a rapid, efficient, and safer alternative for MPXV vaccine design. Here, MPXV proteins associated with viral infection were analyzed for immunogenic epitopes to design multi-epitope vaccines based on B-cell, CD4+, and CD8+ epitopes. Epitopes were selected based on allergenicity, antigenicity, and toxicity parameters. The prioritized epitopes were then combined via peptide linkers and N-terminally fused to various protein adjuvants, including PADRE, beta-defensin 3, 50S ribosomal protein L7/12, RS-09, and the cholera toxin B subunit (CTB). All vaccine constructs were computationally validated for physicochemical properties, antigenicity, allergenicity, safety, solubility, and structural stability. The three-dimensional structure of the selected construct was also predicted. Moreover, molecular docking and molecular dynamics (MD) simulations between the vaccine and the TLR-4 immune receptor demonstrated a strong and stable interaction. The vaccine construct was codon-optimized for high expression in the E. coli and was finally cloned in silico into the pET21a (+) vector. Collectively, these results could represent innovative tools for vaccine formulation against MPXV and be transformative for other infectious diseases. Full article

Viruses use a range of sophisticated strategies to evade detection by cytotoxic T-lymphocytes (CTLs) within host cells. Beyond elaborating dedicated viral proteins that disrupt the MHC class I antigen-presentation machinery, some viruses possess intrinsic, cis-acting genome-encoded elements that interfere with antigen processing and display. These protein features, including G-quadruplex motifs, repetitive peptide sequences, and rare-codon usage, counterintuitively limit production of proteins critical to virus survival, particularly during latency. By slowing viral protein synthesis, these features reduce antigen production and proteosomal degradation, ultimately limiting the generation of peptides for MHC I presentation. These built-in evasion tactics enable viruses to remain “invisible” to CTLs during latency. While these primary sequence intrinsic immune evasion (PSI) mechanisms are well-described in select herpesviruses, emerging evidence suggests that they may also play a critical role in RNA viruses. How these proteins are made, rather than what they functionally target, determines their immune evasion properties. Understanding PSI mechanisms could rationally inform the design of engineered viral antigens with altered or removed evasion elements to restore antigen CTL priming and activation. Such vaccine strategies have the potential to enhance immune recognition, improve clearance of chronically infected cells, and contribute to the treatment of persistent viral infections and virus-associated cancers. Full article

Fasciola gigantica (F. gigantica) is a vital parasite that causes fasciolosis. Liver fluke infections affect livestock animals, and the Fasciola species (Fasciola spp.) vaccine has been tested for many types of these diseases. Currently, computer-based vaccine design represents an attractive alternative for constructing vaccines. Thus, this study aimed to design the epitopes of linear B-cells (BCL) and helper T lymphocytes (HTL) using an immunoinformatic approach and to investigate in silico and the mice’s immune response. A non-conserved host region, overlapping F. gigantica cathepsin B proteins (FgCatB), and the highest conserved residue percentages were the criteria used to construct epitopes. The GPGPG linker was used to link epitopes in the multi-epitope Fasciola gigantica cathepsin B (MeFgCatB) peptide. The MeFgCatB peptide has high antigenicity, non-allergenicity, non-toxicity, good solubility, and a high-quality structure. The molecular docking between the MeFgCatB peptide and Toll-like receptor 2 (TLR-2) was evaluated. The IgM, IgG1, and IgG2 levels were elevated in silico. In mice, the MeFgCatB peptide was synthesized and administered as an injection. The MeFgCatB-specific IgG1 and IgG2a levels were elevated after week 2, showing a predominance of IgG1. The rFgCatB1, rFgCatB2, and rFgCatB3 were detected using the MeFgCatB peptide-immunized sera. The MeFgCatB peptide-immunized sera were detected at approximately 28–34 kDa in the whole body. In addition, the MeFgCatB immunized sera can positively signal at the caecal epithelium in the NEJ, 4WKJ, and adult stages. In summary, the MeFgCatB peptide is able to induce mixed Th1/Th2 immune responses with Th2 dominating and to detect the native protein of F. gigantica. The MeFgCatB peptide should help against F. gigantica in future experiments. Full article

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy with high recurrence rates even after curative resection and adjuvant chemotherapy. Although immunotherapeutic approaches, such as immune checkpoint blockade (ICB), have revolutionized the treatment of some solid tumor malignancies, this has not been the case for PDAC. Several characteristics of PDAC, including its distinctive desmoplastic tumor microenvironment (TME), intratumor heterogeneity, and poor antigenicity and immune cell infiltration, contribute to its dismal immunotherapeutic landscape. Cancer vaccines offer one approach to overcoming these barriers, particularly in the resectable or borderline resectable settings, where tumor burden is low and immunosuppression is less pronounced. Various vaccination platforms have been tested in the clinical setting, from off-the-shelf peptide-based vaccines (e.g., AMPLFIFY-201 study, where over 80% of participants exhibited T-cell and biomarker responses) to personalized neoantigen mRNA vaccine approaches (e.g., autogene cevumeran, with significant responders experiencing longer median recurrence-free survival (RFS)). The key considerations for enhancing the efficacy of vaccination include combinations with chemotherapy, radiotherapy, and/or ICBs, as well as selecting appropriate immunomodulators or adjuvants. Recent results suggest that with continued mechanistic advancement and novel therapeutic development, cancer vaccines may finally be poised for clinical success in PDAC. Full article

Background/Objectives: Head and neck squamous cell carcinoma (HNSCC) is the seventh most common cancer, with limited responsiveness to immune checkpoint inhibitors (ICIs). Cancer vaccine therapy is a promising novel immunotherapeutic approach that stimulates tumor-specific T cells. Receptor tyrosine kinase-like orphan receptor 1 (ROR1), which is overexpressed in malignant tumors but minimally expressed in normal tissues, presents a promising target for immunotherapy. This study aimed to evaluate ROR1 as a target for helper T lymphocyte (HTL)-based peptide vaccine immunotherapy in HNSCC. Methods: ROR1 expression in HNSCC tissues was assessed by immunohistochemistry. A novel ROR1-derived epitope (ROR1_403–417) was identified and used to generate ROR1-reactive HTLs. Functional assays measuring IFN-γ and granzyme B secretion, as well as direct cytotoxicity, were performed. The effects of ICIs on HTL activity were also examined. The presence of ROR1-reactive T cells in the peripheral blood of patients with HNSCC was evaluated. Results: ROR1 positivity rates in HNSCC tissues were significantly higher (80.0%) than those in healthy controls (16.7%), and high ROR1 expression correlated with advanced clinical stages. HTL lines recognized the ROR1_403–417 peptide in a human leukocyte antigen (HLA)-DR-restricted manner, secreted effector cytokines, and exhibited direct cytotoxicity against ROR1+ tumor cells. Dual PD-L1/PD-L2 blockade further enhanced HTL responses. ROR1-reactive T cells were detected in the peripheral blood of patients with HNSCC. Conclusions: ROR1 represents a promising target for immunotherapy in HNSCC. The ROR1_403–417 peptide can elicit ROR1-reactive HTLs that exhibit antitumor responses against HNSCC cell lines, which can be enhanced by ICIs. These findings support the potential of ROR1-targeted peptide vaccine therapy for HNSCC. Full article

Cyclophosphamide (CPX) is an alkylating agent commonly used for various hematological and solid malignancies. In addition to its use as a cytotoxic agent to directly kill tumor cells, numerous immunomodulatory properties of CPX in the tumor microenvironment (TME) of several cancer types have also been documented. These properties include the selective depletion of immune-suppressive regulatory T cells (Tregs), triggering of immunogenic cell death (ICD) and enhanced antigen presentation, and release of type I interferons (IFNs). Moreover, preclinical models as well as human clinical trials have investigated the efficacy of the low-dose “metronomic” scheduling of CPX in combination with immunotherapies such as immune checkpoint inhibitors, dendritic cell tumor vaccines, and tumor antigen peptide vaccines. The metronomic dosing schedule involves administering a continuous (or frequent, such as daily) low dose of chemotherapy rather than using the canonical approach of administering the maximum tolerated dose. Despite the approval of immune checkpoint inhibitors for clinical usage against an increasing number of cancers, many malignancies simply do not respond to checkpoint inhibition, in part due to the heterogeneous intratumoral network of immune-suppressive cell populations. The immunomodulatory effects of cyclophosphamide have strong translational applicability and could serve to enhance and bolster anti-tumor immunity, potentially synergizing with immune checkpoint inhibitors and other existing immunotherapy agents. Full article

Background/Objectives: Leishmaniasis is a prevailing infectious disease transmitted via infected phlebotomine sandflies. The lack of an efficient vaccine with respect to immunogenic antigens and adjuvanted delivery systems impedes its control. Following the induction of immune responses in mice vaccinated with multi-epitope Leishmania peptides (LeishPts) encapsulated in doubly adjuvanted self-nanoemulsifying drug delivery systems (ST-SNEDDSs), this study aims to assess ST-SNEDDS-based nanoemulsions as vehicles for the delivery of antigenic proteins. Methods: Model antigens (e.g., BSA-FITC, OVA) were encapsulated in ST-SNEDDS after being complexed with the cationic phospholipid dimyristoyl phosphatidylglycerol (DMPG) via hydrophobic ion pairing. The nanoemulsions were characterized with respect to droplet diameter, zeta potential, stability, protein loading, protein release from the nanodroplets in different release media and cell uptake. Results: Both model antigens exhibited high encapsulation efficiency (>95%) and their release from the nanodroplets was shown to be strongly affected by the type of release medium (e.g., PBS, FBS 10% v/v) and the ratio of its volume to that of the oily phase, in agreement with predictions of protein release. Protein-loaded nanoemulsion droplets labeled with Cy-5 were found to be efficiently taken up by macrophages (J774A.1) in vitro. However, no colocalization of the labeled nanodroplets and BSA-FITC could be observed. Conclusions: It was revealed that in contrast with LeishPts, whole protein molecules may not be appropriate antigenic cargo for ST-SNEDDS formulations due to the rapid protein release from the nanodroplets in release media simulating in vitro culture and in vivo conditions such as FBS 10% v/v. Full article

Background: Cancer vaccines represent a groundbreaking advancement in cancer immunotherapy, utilizing tumor antigens to induce tumor-specific immune responses. However, challenges like tumor-induced immune resistance and technical barriers limit the widespread application of predefined antigen vaccines. Here, we investigated the potential of viral protein R (Vpr) peptides as effective candidates for constructing anonymous antigen vaccines in situ by directly injecting at the tumor site and releasing whole-tumor antigens, inducing robust anti-tumor immune responses to overcome the limitations of predefined antigen vaccines. Methods: The cytotoxic effects of Vpr peptides were evaluated using the CCK8 reagent kit. Membrane penetration ability of Vpr peptides was observed using a confocal laser scanning microscope and quantitatively analyzed using flow cytometry. EGFR levels in the cell culture supernatants of cells treated with Vpr peptides were evaluated using an ELISA. Surface exposure of CRT on the tumor cell surface was observed using a confocal laser scanning microscope and quantitatively analyzed using flow cytometry. The secretion levels of ATP from tumor cells were evaluated using an ATP assay kit. HMGB1 release was evaluated using an ELISA. Mouse (Male C57BL/6 mice aged 4 weeks) MC38 and LLC bilateral subcutaneous tumor models were established to evaluate the therapeutic effects of Vpr peptides through in situ vaccination. Proteomic analysis was performed to explore the mechanism of anti-tumor activity of Vpr peptides. Results: Four Vpr peptides were designed and synthesized, with P1 and P4 exhibiting cytotoxic effects on tumor cells, inducing apoptosis and immunogenic cell death. In mouse tumor models, in situ vaccination with Vpr peptide significantly inhibited tumor growth and activated various immune cells. High-dose P1 monotherapy demonstrated potent anti-tumor effects, activating DCs, T cells, and macrophages. Combining ISV of P1 with a CD47 inhibitor SIRPαFc fusion protein showed potent distant tumor suppression effects. Proteomic analysis suggested that Vpr peptides exerted anti-tumor effects by disrupting tumor cell morphology, movement, and adhesion, and promoting immune cell infiltration. Conclusions: The designed Vpr peptides show promise as candidates for in situ vaccination, with significant anti-tumor effects, immune activation, and favorable safety profiles observed in mouse models. In situ vaccination with Vpr-derived peptides represents a potential approach for cancer immunotherapy. Full article

Background: Vaccines are crucial for preventing infectious diseases, as both humoral and cellular immune responses play a vital role in combating viral infections. The cellular immune response is crucial against SARS-CoV-2, particularly with the emergence of new variants that evade antibody neutralization. This study focuses on the immune memory response in individuals who have been vaccinated with the Sinopharm BBIBP-CorV vaccine. Methods: A cross-sectional study evaluated lymphocyte subpopulations using flow cytometry in 52 vaccinated adults (30 females, 22 males) who had been exposed to SARS-CoV-2 or diagnosed with COVID-19. Conducted from February to June 2023 during the Omicron variant’s circulation, this study assessed antigens—CD154 in CD4+ T cells, CD107 and CD314 in CD8+ T cells, CD314 in NK cells, and CD86 in CD19 B cells—after stimulation with viral peptides and an inactivated virus. Granzyme B and IFN-γ were quantified using ELISA. Results: The memory response, regardless of gender, age, or Body Mass Index (BMI), was mild but significant upon exposure to a viral antigen or inactivated virus. An increase in the secretion of IFN-γ and granzyme B was also observed. Conclusions: It is suggested that the vaccine was able to generate a mild long-term memory against the SARS-CoV-2 virus in vaccinated adult individuals, independent of gender and BMI. Full article

Helicobacter pylori (H. pylori) infection is a leading cause of gastritis, peptic ulcers, and gastric cancer, affecting more than half of the global population. Its persistence in the acidic gastric environment and its ability to evade host immunity present major treatment challenges. Although antibiotics remain the standard therapy, rising antimicrobial resistance has reduced treatment efficacy, prompting the search for alternative and adjunct approaches. Emerging therapies include probiotics, antimicrobial peptides (AMPs), and plant-derived compounds, which target H. pylori through membrane disruption, immunomodulation, or direct antimicrobial activity. Novel drug delivery systems and microbiota-sparing interventions are also being investigated. Additionally, vaccine development offers a promising strategy for long-term protection, though challenges related to antigenic variability and host-specific responses remain. Despite these advances, treatment variability and the limited clinical validation of alternatives hinder progress. A multifaceted approach integrating microbiome research, host–pathogen interactions, and new therapeutic agents is essential for future success. Full article

Therapeutic cancer vaccines are a new growth point of biomedicine with broad industrial prospects in the post-COVID-19 era. Many large international pharmaceutical companies and emerging biotechnology companies are deploying different tumor therapeutic cancer vaccine projects, focusing on promoting their clinical transformation, and the vaccine industry has strong momentum for development. Such vaccines are also the core engine and pilot site for the development of new vaccine targets, new vectors, new adjuvants, and new technologies, which play a key role in promoting the innovation and development of vaccines. Various therapeutic cancer vaccines, such as viral vector vaccines, bacterial vector vaccines, cell vector vaccines, peptide vaccines, and nucleic acid vaccines, have all been applied in clinical research. With the continuous development of technology, therapeutic cancer vaccines are evolving towards the trends of precise antigens, efficient carriers, diversified adjuvants, and combined applications. For instance, the rapidly advancing mRNA-4157 vaccine is a typical representative that combines personalized antigens with efficient delivery vectors (lipid nanoparticles, LNPs), and it also shows synergistic advantages in melanoma patients treated in combination with immune checkpoint inhibitors. In this article, we will systematically discuss the current research and development status and clinical research progress of various therapeutic cancer vaccines. Full article