Search Results (1,910)

Background: It is still challenging to develop effective vaccines against tumorigenic human gammaherpesviruses such as Epstein–Barr virus (EBV). A major obstacle is the lack of a small animal model that reproduces the natural infection course of human gammaherpesviruses to allow for proper assessment of vaccine efficacy. Murine gammaherpesvirus 68 (MHV68) is a natural pathogen of wild rodents and laboratory mice and therefore can be used as a surrogate for human gammaherpesviruses to evaluate vaccination strategies. Methods: In this study, two mRNA vaccine candidates were generated, one encoding a fusion protein of the MHV68 gH with the gL (gHgL-mRNA) and the other expressing the MHV68 gB protein (gB-mRNA). The immunogenicity and protective efficacy of the mRNA vaccine candidates were evaluated in a mouse model of MHV68 infection. Results: The gHgL-mRNA but not the gB-mRNA candidate vaccine was able to induce neutralizing antibodies in mice, whereas both vaccines could elicit antigen-specific T-cell responses. Following MHV68 intranasal inoculation, complete blocking of the establishment of viral latency was observed in some mice immunized with individual gHgL-mRNA or gB-mRNA vaccines. Notably, co-immunization with the two mRNA vaccines appeared to be more effective than individual vaccines, achieving sterile immunity in 50% of the vaccinated mice. Conclusions: This study demonstrates that immunization with mRNA platform-based subunit vaccines is indeed capable of preventing MHV68 latent infection, thus validating a safe and efficacious vaccination strategy that may be applicable to human gammaherpesviruses. 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

Stage IV colorectal cancer has a poor prognosis, and liver metastases are prone to recurrence, even after resection. This study aimed to identify common cancer antigens, using immunohistochemical staining, as promising targets for antigen-specific immunotherapies in colorectal cancer. We analyzed expression levels and intracellular localization of seven common cancer antigens, CLDN1, EphB4, LAT1, FOXM1, HSP105α, ROBO1, and SPARC, and human leukocyte antigen (HLA) class I via immunohistochemical staining of 85 surgical specimens from primaries and liver metastases. Staining intensity and positive staining were scored to evaluate antigen expression. In 25 primaries, seven cancer antigens were expressed in 88–96% of cases, while HLA class I was expressed on the cell membrane in 80.0% of cases. In 60 liver metastases, FOXM1 and SPARC expression were approximately half that observed in the primaries. Other antigens and HLA class I were highly expressed in both. Most of the primaries and liver metastases may benefit from chimeric antigen receptor-T cell therapy targeting CLDN1, EphB4, and LAT1. Cases with high HLA class I expression may be suitable for vaccine-based and T cell receptor-T cell therapy targeting CLDN1, EphB4, LAT1, FOXM1, HSP105α, ROBO1, and SPARC for primaries and targeting antigens, excluding FOXM1 and SPARC, for liver metastases. Full article

Myxoma virus (MYXV), a rabbit-specific poxvirus and non-pathogenic in humans and mice, is an excellent candidate oncolytic virus for cancer therapy. MYXV also has immunotherapeutic benefits. In ovarian cancer (OC), immunosuppressive tumor-associated macrophages (TAMs) are key to inhibiting antitumor immunity while hindering therapeutic benefit by chemotherapy and dendritic cell (DC) vaccine. Because MYXV favors binding/entry of macrophages/monocytes, we examined the therapeutic potential of MYXV against TAMs. We found previously that a replication-defective MYXV with targeted deletion of an essential gene, M062R, designated ΔM062R MYXV, activated both the host DNA sensing pathway and the SAMD9 pathway. Treatment with ΔM062R confers therapeutic benefit comparable to that of wild-type replicating MYXV in preclinical models. Here we found that ΔM062R MYXV, when integrated with cisplatin and DC immunotherapy, further improved treatment benefit, likely through promoting tumor antigen-specific T cell function. Moreover, we also tested ΔM062R MYXV in targeting human immunosuppressive TAMs from OC patient ascites in a co-culture system. We found that ΔM062R treatment subverted the immunosuppressive properties of TAMs and elevated the avidity of cytokine production in tumor antigen-specific CD4⁺ T cells. Overall, ΔM062R presents a promising immunotherapeutic platform as a beneficial adjuvant to chemotherapy and DC vaccine. 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

Background: Fowl typhoid (FT), a septicemic infection caused by Salmonella Gallinarum (SG), and H9N2 avian influenza are two economically important diseases that significantly affect the global poultry industry. Methods: We exploited the live attenuated Salmonella Gallinarum (SG) mutant JOL3062 (SG: ∆lon ∆pagL ∆asd) as a delivery system for H9N2 antigens to induce an immunoprotective response against both H9N2 and FT. To enhance immune protection against H9N2, a prokaryotic and eukaryotic dual expression plasmid, pJHL270, was employed. The hemagglutinin (HA) consensus sequence from South Korean avian influenza A virus (AIV) was cloned under the Ptrc promoter for prokaryotic expression, and the B cell epitope of neuraminidase (NA) linked with matrix protein 2 (M2e) was placed for eukaryotic expression. In vitro and in vivo expressions of the H9N2 antigens were validated by qRT-PCR and Western blot, respectively. Results: Oral immunization with JOL3121 induced a significant increase in SG and H9N2-specific serum IgY and cloacal swab IgA antibodies, confirming humoral and mucosal immune responses. Furthermore, FACS analysis showed increased CD4+ and CD8+ T cell populations. On day 28 post-immunization, there was a substantial rise in the hemagglutination inhibition titer in the immunized birds, demonstrating neutralization capabilities of immunization. Both IFN-γ and IL-4 demonstrated a significant increase, indicating a balance of Th1 and Th2 responses. Intranasal challenge with the H9N2 Y280 strain resulted in minimal to no clinical signs with significantly lower lung viral titer in the JOL3121 group. Upon SG wildtype challenge, the immunized birds in the JOL3121 group yielded 20% mortality, while 80% mortality was recorded in the PBS control group. Additionally, bacterial load in the spleen and liver was significantly lower in the immunized birds. Conclusions: The current vaccine model, designed with a host-specific pathogen, SG, delivers a robust immune boost that could enhance dual protection against FT and H9N2 infection, both being significant diseases in poultry, as well as ensure public health. Full article

Vaccine adjuvants are non-immunogenic agents that enhance or modulate immune responses to co-administered antigens and are essential to modern vaccines. Despite their importance, few are approved for human use. The rise of new pathogens and limited efficacy of some existing vaccines underscore the need for more advanced and effective formulations, particularly for vulnerable populations. Aluminum-based adjuvants are commonly used in vaccines and effectively promote humoral immunity. However, they mainly induce a Th2-biased response, making them suboptimal for diseases requiring cell-mediated immunity. In contrast, saponin-based adjuvants from the Quillajaceae family elicit a more balanced Th1/Th2 response and generate antigen-specific cytotoxic T cells (CTL). Due to ecological damage and limited availability caused by overharvesting Quillaja saponaria Molina barks, efforts have intensified to identify alternative plant-derived saponins with enhanced efficacy and lower toxicity. Quillaja brasiliensis (A.St.-Hil. and Tul.) Mart. (syn. Quillaja lancifolia D.Don), a related species native to South America, is considered a promising renewable source of Quillajaceae saponins. In this review, we highlight recent advances in vaccine adjuvant research, with a particular focus on saponins extracted from Q. brasiliensis leaves as a sustainable alternative to Q. saponaria saponins. These saponin fractions are structurally and functionally comparable, exhibiting similar adjuvant activity when they were formulated with different viral antigens. An alternative application involves formulating saponins into nanoparticles known as ISCOMs (immune-stimulating complexes) or ISCOM-matrices. These formulations significantly reduce hemolytic activity while preserving strong immunoadjuvant properties. Therefore, research advances using saponin-based adjuvants (SBA) derived from Q. brasiliensis and their incorporation into new vaccine platforms may represent a viable and sustainable solution for the development of more less reactogenic, safer, and effective vaccines, especially for diseases that require a robust cellular immunity. Full article

Background: Toxoplasma gondii (T. gondii) causes severe disease in immunocompromised individuals and pregnant women, underscoring the urgent need for effective vaccines against toxoplasmosis. The dense granule protein 5 (GRA5) of T. gondii plays a key role in parasitic cyst formation. Methods: This study evaluated the protective immune responses induced by a virus-like particle (VLP) vaccine expressing the T. gondii-derived antigen GRA5 in a mouse model challenged with the ME49 strain of T. gondii. GRA5 VLPs were generated using a baculovirus expression system, and VLP formation was confirmed by Western blotting and visualized using transmission electron microscopy. Mice were intranasally immunized with GRA5 VLPs three times at 4-week intervals to induce immune responses, followed by infection with T. gondii ME49. Results: Intranasal immunization with GRA5 VLPs induced parasite-specific IgG antibody responses in the serum and both IgG and IgA antibody responses in the brain. Compared to the non-immunized group, immunized mice exhibited significantly higher levels of germinal center B cells and antibody-secreting cell responses. Moreover, the VLP vaccine suppressed the production of IFN-γ and IL-6 cytokines, leading to a significant reduction in brain inflammation and decreased cyst counts following lethal challenge with T. gondii ME49 infection. Conclusion: These findings suggest that the GRA5 VLP vaccine derived from T. gondii elicits a protective immune response, highlighting its potential as an effective vaccine candidate against toxoplasmosis. Full article

Human cytomegalovirus (HCMV) establishes lifelong latency in the host, with the bone marrow (BM) CD34+ cells serving as a key reservoir. To investigate tissue-specific immune responses to CMV, we analysed paired peripheral blood mononuclear cells (PBMCs) and bone marrow mononuclear cells (BMMNCs) from HCMV-seropositive donors using multiparametric flow cytometry and cytokine FluroSpot assays. We assessed immune cell composition, memory T cell subsets, cytokine production, cytotoxic potential, activation marker expression, and checkpoint inhibitory receptor (CIR) profiles, both ex vivo and following stimulation with lytic and latent HCMV antigens. BMMNCs were enriched in CD34+ progenitor cells and exhibited distinct T cell memory subset distributions. HCMV-specific responses were compartmentalised: IFN-γ responses predominated in PBMCs following lytic antigen stimulation, while IL-10 and TNF-α responses were more prominent in BMMNCs, particularly in response to latent antigens. US28-specific T cells in the BM showed elevated expression of CD39, PD-1, BTLA, CTLA-4, ICOS, and LAG-3 on CD4+ T cells and increased expression of PD-1, CD39, BTLA, TIGIT, LAG-3, and ICOS on CD8+ T cell populations, suggesting a more immunoregulatory phenotype. These findings highlight functional and phenotypic differences in HCMV-specific T cell responses between blood and bone marrow, underscoring the role of the BM niche in shaping antiviral immunity and maintaining viral latency. 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

Adoptive cell therapies have transformed the treatment landscape for hematologic malignancies. Yet, translation to solid tumors remains constrained by antigen heterogeneity, an immunosuppressive tumor microenvironment (TME), and poor persistence of conventional CAR-T cells. In response, innate immune cell platforms, particularly chimeric antigen receptor–engineered natural killer (CAR-NK) cells and chimeric antigen receptor–macrophages (CAR-MΦ), have emerged as promising alternatives. This review summarizes recent advances in the design and application of CAR-NK and CAR-MΦ therapies for solid tumors. We highlight key innovations, including the use of lineage-specific intracellular signaling domains (e.g., DAP12, 2B4, FcRγ), novel effector constructs (e.g., NKG7-overexpressing CARs, TME-responsive CARs), and scalable induced pluripotent stem cell (iPSC)-derived platforms. Preclinical data support enhanced antitumor activity through mechanisms such as major histocompatibility complex (MHC)-unrestricted cytotoxicity, phagocytosis, trogocytosis, cytokine secretion, and cross-talk with adaptive immunity. Early-phase clinical studies (e.g., CT-0508) demonstrate feasibility and TME remodeling with CAR-MΦ. However, persistent challenges remain, including transient in vivo survival, manufacturing complexity, and risks of off-target inflammation. Emerging combinatorial strategies, such as dual-effector regimens (CAR-NK⁺ CAR-MΦ), cytokine-modulated cross-support, and bispecific or logic-gated CARs, may overcome these barriers and provide more durable, tumor-selective responses. Taken together, CAR-NK and CAR-MΦ platforms are poised to expand the reach of engineered cell therapy into the solid tumor domain. Full article

Background/Objectives: Organ transplantation is a life-saving intervention for patients with terminal organ failure, but long-term success is hindered by graft rejection and dependence on lifelong immunosuppressants. These drugs pose risks such as opportunistic infections and malignancies. Chimeric antigen receptor (CAR) technology, originally developed for cancer immunotherapy, has been adapted to regulatory T cells (Tregs) to enhance their antigen-specific immunosuppressive function. This systematic review evaluates the preclinical development of CAR-Tregs in promoting graft tolerance and suppressing graft-versus-host disease (GvHD). Methods: A systematic review following PROSPERO guidelines (CRD420251073207) was conducted across PubMed, Scopus, and Web of Science for studies published from 2015 to 2024. After screening 105 articles, 17 studies involving CAR-Tregs in preclinical or in vivo transplant or GvHD models were included. Results: CAR-Tregs exhibited superior graft-protective properties compared to unmodified or polyclonal Tregs. HLA-A2-specific CAR-Tregs consistently improved graft survival, reduced inflammatory cytokines, and suppressed immune cell infiltration across skin, heart, and pancreatic islet transplant models. The inclusion of CD28 as a co-stimulatory domain enhanced Treg function and FOXP3 expression. However, challenges such as Treg exhaustion, tonic signaling, and reduced in vivo persistence were noted. Some studies reported synergistic effects when CAR-Tregs were combined with immunosuppressants like rapamycin or tacrolimus. Conclusions: CAR-Tregs offer a promising strategy for inducing targeted immunosuppression in allogeneic transplantation. While preclinical findings are encouraging, further work is needed to optimize CAR design, ensure in vivo stability, and establish clinical-scale manufacturing before translation to human trials. 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

Background/Objectives: Pancreatic cancer remains the fourth leading cause of cancer-related deaths. While peripheral blood-derived mature dendritic cell (mDC) vaccines have shown potential in eliciting anti-tumor immune responses, clinical efficacy has been limited. This study aimed to enhance the potency and scalability of DC-based immunotherapy by developing an allogeneic DC platform derived from CD34⁺ hematopoietic stem cells (HSCs), genetically engineered to overexpress CD93, CD40L, and CXCL13, followed by maturation and tumor antigen pulsing. Methods: Engineered DCs were generated from CD34⁺ HSCs and matured in vitro after lentiviral transduction of CD93, CD40L, and CXCL13. Tumor lysates were used for antigen pulsing. A scrambled-sequence control DC was used for comparison. In vitro assays were performed to assess T cell activation and tumor cell killing. In vivo efficacy was evaluated using orthotopic pancreatic tumors in BLT and PBMC-humanized NSG mice established with the MiaPaca-2 (MP2) cell line. Results: Engineered DCs significantly enhanced T cell activation and tumor-specific cytotoxicity in vitro compared to control DCs. Antigen pulsing further amplified immune activation. In vivo, treated humanized mice showed increased CD4⁺, CD8⁺, and NK cell frequencies in peripheral blood and within tumors, correlating with reduced tumor burden. Conclusions: Our data shows that the antigen-pulsed, engineered DCs have the potency to activate immune cells, which leads to a significant reduction in pancreatic tumors and therefore could potentially provide an effective therapeutic opportunity for the treatment of pancreatic cancer and other solid tumors. Full article

Venous thromboembolism (VTE) represents a significant complication of cancer immunotherapy, with emerging evidence suggesting distinct pathophysiological mechanisms compared to traditional chemotherapy-associated thrombosis. This narrative review examines the epidemiology and pathogenesis of VTE in patients receiving immunotherapies for cancer including immune checkpoint inhibitors (ICIs), chimeric antigen receptor (CAR) T-cell therapy, bispecific T-cell engagers (BiTEs), among others. Real-world studies demonstrate a wide range of VTE incidence rates in ICI recipients, with potential mechanisms including exacerbated underlying interleukin-8-mediated inflammatory pathways and consequent neutrophil extracellular trap (NET) formation. CAR T-cell therapy is associated with unique hemostatic challenges, including concurrent thrombotic and bleeding risks related to cytokine release syndrome. Current risk assessment tools show limited predictive utility in patients receiving immunotherapies for cancer, highlighting the need for novel stratification models. Future research priorities include developing immunotherapy-specific risk prediction tools, elucidating mechanistic pathways linking immune activation to thrombosis, and establishing evidence-based and tailored thromboprophylaxis strategies. As cancer immunotherapy continues to evolve, understanding and mitigating thrombotic complications remains crucial for optimizing patient outcomes. Full article