Search Results (278)

The discovery of neoantigens and their application in cancer vaccines have brought about a paradigm shift in cancer immunotherapy, similar to the way in which immune checkpoint inhibitors redefined therapeutic strategies for cancer treatment. Early neoantigen vaccine approaches primarily focused on eliciting HLA class I-restricted CD8⁺ cytotoxic T lymphocyte (CTL) responses, whereas it has become clear that such strategies alone may be insufficient to establish durable and effective antitumor immunity. Increasing attention has therefore shifted toward HLA class II-restricted neoantigens (“helper neoantigens”) that activate tumor-specific CD4⁺ helper T cells. Recent studies have revealed that neoantigen-reactive CD4⁺ helper T cells play a central role in coordinating antitumor immune responses through dendritic cell licensing, thereby sustaining CD8⁺ CTL function, preventing T-cell exhaustion, and promoting the generation of long-lived memory T cells. These findings have highlighted the pivotal role of helper neoantigens in shaping vaccine efficacy. In this review, we discuss the mechanistic basis underlying the contribution of helper neoantigens to tumor immunity and highlight recent advances in the real-world application of helper neoantigen-based vaccine strategies. Full article

H9N2 avian influenza virus (AIV) continues to mutate, leading to immunosuppression and secondary infections in poultry. Traditional inactivated vaccines mainly induce humoral immunity and have limited cross-protection efficacy against various subtypes of virus strains. In this study, we targeted the HA2 and M1 proteins of H9N2 as antigens and used immunoinformatics methods to design a broad-spectrum multi-epitope vaccine (MEV) that can simultaneously activate humoral and cellular immunity. Firstly, through systematic evolutionary analysis and sequence comparison, highly conserved amino acid sequence regions were selected from HA2 and M1 proteins. B-cell epitopes were predicted in the HA2 conserved sequence, and cytotoxic T lymphocyte (CTL) and helper T lymphocyte (HTL) epitopes were predicted in the M1 conserved sequence. Three candidate vaccines containing different epitope combinations were constructed. After secondary structure and physicochemical property comparisons, HM1 was determined as the optimal scheme. HM1 contains three B cell epitopes, two CTL epitopes, and three HTL epitopes, and was connected to chicken β-defensin at the N-terminus as a molecular adjuvant; a dendritic cell-targeting peptide was added at the C-terminus. The HM1 tertiary structure optimized by GalaxyRefine met the standards of a reliable model. The molecular docking results indicated that HM1 can form stable binding with chicken TLR2, TLR4, MHC I, and MHC II molecules, with binding free energies of −7.1 kcal/mol and −6.1 kcal/mol, respectively, and can form multiple hydrogen bonds and salt bridges. Normal mode analyses revealed that the HM1–TLR complex exhibits favorable dynamic properties at the computational level. The immune simulation prediction results showed that after vaccination with HM1, specific antibodies can be induced, B cells, helper T cells, and cytotoxic T cells can be activated, and IFN-γ and IL-2 can be secreted. In summary, the HM1 designed based on the conserved regions of HA2 and M1 proteins has good physicochemical stability and immunogenicity, providing a theoretical basis for the development of broad-spectrum and highly effective H9N2 vaccines. Full article

In this article, we formulated a mathematical model to describe SARS-CoV-2 development in humans, accounting for the dynamics of susceptible and infected epithelial cells, viral particles, ACE2 receptors, cytotoxic T lymphocytes (CTLs), and antibodies. The basic reproduction number and equilibrium points are derived, with stability analysis showing that the disease-free equilibrium is maintained when ${\mathcal{R}}_0<1$, while an endemic equilibrium arises for ${\mathcal{R}}_0>1$. Additionally, Hopf bifurcating periodic solutions are observed under elevated viral replication and infection rates. To capture therapeutic intervention, an impulsive control framework based on antibody-mediated drug administration is introduced. The existence and stability of a disease-free periodic orbit are established through the impulsive reproduction number ${\mathcal{R}}_0^{imp}$, with stability ensured when ${\mathcal{R}}_0^{imp}<1$. The findings from numerical simulations support the analytical outcomes, proving the efficacy of impulsive control in suppressing viral persistence. The current research work offers important knowledge on the interaction between immune system and impulsive control mechanisms, which serves as a basis to develop therapies against SARS-CoV-2. Full article

The continuous evolution of the SARS-CoV-2 virus, marked by the emergence of new variants, poses a significant threat to the efficacy of existing vaccines. However, a promising approach to addressing vaccine failure caused by viral mutations (particularly in the spike protein) is the development of a variant-proof (conserved), non-spike, multiepitope universal nanostructure vaccine with multifunctionality, biocompatibility, self-adjuvanticity, and structural similarity to pathogens in terms of size and shape. This study aimed to design a self-assembled nanostructure vaccine (SANV) featuring pentameric and trimeric coiled-coil peptide motifs, as well as other functional motifs, including epitopes, TAT, PADRE, and adjuvant. The cytotoxic T lymphocyte (CTL), helper T lymphocyte (HTL), and B lymphocyte (BL) epitopes of SANV were screened from the IEDB with more than 50% individual predicted population coverage (PPC) and fused using linkers to enable self-assembly. The multimerization of the 24 SANV monomers was modeled using the GalaxyHomomer and AlphaFold web servers. Subsequently, the leading SANV constructs with (SANVa9) and without (SANVb6) adjuvant were analyzed for their physicochemical profiles and assessed for antigenicity, allergenicity, solubility, and antioxidant potential. Furthermore, the molecular interactions, specificity, and stability of SANVa9 and SANVb6 with the broadly neutralizing sarbecovirus antibody 5817 and toll-like receptors (TLR2, TLR3, and TLR7) were analyzed using molecular docking and simulation over a 100-nanosecond time scale. Finally, the comparative immune simulation profiles of SANVa9 and SANVb6 with controls indicated stronger, broad-spectrum immune responses that could be translated into in vitro and in vivo studies and warrant further evaluation before clinical use. Full article

Background/Objectives: Tuberculosis, caused by Mycobacterium tuberculosis, remains a major global health challenge requiring novel prevention strategies. This study aims to developed an immunoinformatics-guided framework coupled with experimental screening to prioritize for multi-epitope mRNA vaccine design. Methods: Eight immunologically relevant antigens were computationally analyzed to predict cytotoxic (CTL) epitopes and helper T lymphocyte (HTL) epitopes. Population coverage, immune simulation, molecular docking, and normal mode analysis (NMA) were performed in silico. To evaluate peptide immunoreactivity, human IFN-γELISPOT assays were conducted using the candidate peptides, though HLA restriction was not experimentally validated. Results: The workflow identified 14 candidate CTL and 8 HTL epitopes, yielding an estimated global population coverage of 82.6% (60.7% in China; 51.2% in Indonesia). Immune simulations predicted robust humoral and Th1-associated cellular responses, though sustained CD8⁺ memory responses appeared limited. Docking and NMA suggested favorable structural interactions with TLR3 and TLR4. Crucially, the IFN-γ ELISPOT assay validated eight reactive epitopes that partially coincided with computational predictions within the tested donor group. Conclusions: This study establishes an integrated computational–experimental workflow for T cell epitope prioritization. The identified reactive epitopes provide a preliminary immunological basis and candidate pool for the future design and evaluation of multi-epitope mRNA vaccine strategies against tuberculosis. Full article

Epcoritamab, a subcutaneous CD3×CD20 bispecific antibody, has shown substantial activity in relapsed or refractory (R/R) B-cell lymphomas, but the immunological correlates of durable remission and treatment discontinuation remain unclear. We retrospectively analyzed 21 consecutive patients who initiated epcoritamab at our institution between 1 December 2023 and 31 December 2025, including 17 with R/R large B-cell lymphoma (LBCL) and 4 with R/R follicular lymphoma (FL). Clinical follow-up was updated through 18 May 2026. Serial cytotoxic T lymphocyte (CTL) subset and T-cell receptor (TCR) Vβ repertoire analyses were performed in selected cases. Among response-evaluable patients, the overall response rate was 9/14 in LBCL and 4/4 in FL. Median overall survival was 431 days in LBCL and 431.5 days in FL. Progression-free survival was analyzed descriptively because of the small sample size and substantial censoring. A patient with clinically and radiologically suspected central nervous system relapse of LBCL achieved radiological complete remission after epcoritamab treatment. In two LBCL and one FL case in whom epcoritamab was electively discontinued after complete remission, Vβ-skewed CTL populations were observed, and total memory CTLs exceeded total effector CTLs at discontinuation. These exploratory findings suggest that epcoritamab treatment may be associated with longitudinal remodeling of CTL subsets and Vβ-skewed CTL populations in selected responders. The potential relevance of these immunological patterns to durable response and treatment discontinuation should be validated in larger prospective cohorts with functional and sequence-based T-cell analyses. Full article

Toxoplasma gondii is an obligate intracellular protozoan parasite that causes toxoplasmosis, posing a significant threat to human health and livestock production worldwide. Although monovalent DNA or mRNA vaccines often confer only partial protection, whether these platforms can be effectively integrated into a heterologous prime–boost regimen against T. gondii remains to be fully elucidated. Here, we constructed GRA35-encoding DNA and mRNA vaccines and evaluated their immunogenicity and protective efficacy, administered either alone or in heterologous prime–boost combinations, in C57BL/6 and BALB/c mice. Both vaccines induced strong antigen-specific immune responses, with the heterologous prime–boost regimen eliciting the strongest effects and conferring the most robust and consistent protection across both mouse strains. Immunization triggered a predominantly Th1-skewed response characterized by significantly elevated IFN-γ production, accompanied by balanced antigen-specific IgG responses. Moreover, vaccinated mice developed rapid and potent cytotoxic T lymphocyte (CTL) responses. Following challenge with the RH and PRU strains, vaccinated mice exhibited prolonged survival and significantly reduced brain cyst burdens following PRU challenge compared with control groups. Collectively, these findings indicate that GRA35-based nucleic acid vaccines, particularly when administered in a heterologous prime–boost regimen, elicit multifaceted protective immune responses and represent promising vaccine candidates against T. gondii infection. Full article

Background: Currently marketed hepatitis B vaccines are primarily recombinant protein vaccines. However, their antigen immunogenicity is relatively weak, requiring combination with effective adjuvants to enhance the immune response. The development of novel, highly effective adjuvants is a key strategy for optimizing vaccine performance. Polyinosinic-polycytidylic acid (PolyI:C), a synthetic double-stranded RNA analog, activates TLR3/RLR pathways to enhance T-cell priming and cellular immunity. However, its utility as a sole adjuvant is limited by rapid nuclease degradation and poor cytosolic delivery. Lipid nanoparticles (LNPs), a mature delivery platform, enable high encapsulation efficiency, efficient cellular uptake, and endosomal escape. Objectives: This study aimed to evaluate the adjuvant effect of LNP-encapsulated PolyI:C (LNP-PolyI:C) on the immunogenicity of hepatitis B surface antigen (HBsAg) in vivo. Methods: The colloidal stability of LNP-PolyI:C stored at 2–8 °C for 9 months was monitored using dynamic light scattering (DLS) on a Zetasizer Lab instrument. Serum levels of HBsAg-specific IgG, IgG1, and IgG2a antibodies in immunized Kunming mice were measured by enzyme-linked immunosorbent assay (ELISA). The secretion of HBsAg-specific cytokines by splenocytes was analyzed using flow cytometry and enzyme-linked immunospot (ELISpot) assay. Results: The results demonstrated that the LNP-encapsulated PolyI:C adjuvant significantly increased the secretion of HBsAg-specific IFN-γ, IL-2, and TNF-α by splenocytes, indicating a Th1-biased and cytotoxic T lymphocyte (CTL)-mediated cellular immune response. In addition, this formulation markedly elevated serum titers of HBsAg-specific IgG, IgG1, and IgG2a. Conclusions: These findings underscore the advantages of the LNP-PolyI:C adjuvant in enhancing both humoral and cellular immunity, demonstrating its considerable potential as a novel adjuvant. Full article

Background: Porcine epidemic diarrhea virus (PEDV) remains a major threat to the global swine industry, highlighting the urgent need for safe and effective next-generation vaccines. mRNA vaccines have emerged as a promising platform due to their rapid development and favorable safety profile. Objectives: This study aimed to design and perform the preliminary evaluation of a PEDV multi-epitope mRNA vaccine using an immunoinformatics-guided strategy combined with experimental validation. Methods: Immunoinformatics tools were used to identify B-cell and cytotoxic T lymphocyte (CTL) epitopes from the PEDV spike (S), membrane (M), and nucleocapsid (N) proteins. Selected epitopes were assembled into a multi-epitope antigen (E). mRNA constructs encoding S1, S2, and antigen E were synthesized via in vitro transcription and encapsulated into lipid nanoparticles (LNPs). Expression was evaluated in HEK293T cells, and immunogenicity was assessed in mice measuring antigen-specific antibody responses and cytokine levels following immunization. Results: The mRNA constructs exhibited high structural integrity and efficient intracellular translation. The LNP formulations showed good physicochemical stability and delivery efficiency. Immunization with the antigen E mRNA-LNP formulation induced significantly higher PEDV-specific IgG levels compared with control groups. Elevated cytokine levels further indicated activation of both humoral and cellular immune responses. Conclusions: This study presents a feasible workflow for the development of a PEDV multi-epitope mRNA vaccine. The antigen E construct demonstrated favorable immunogenicity in a mouse model, supporting its potential as a promising construct for further investigation and optimization. Although further studies are required to validate antigen expression at the protein level and to further characterize immune mechanisms, these findings provide preliminary evidence supporting the feasibility of multi-epitope mRNA vaccines for PEDV prevention. Full article

Background: Crimean-Congo hemorrhagic fever (CCHF) is a severe tick-borne viral disease with a high fatality rate, and no licensed vaccines are currently available. The nucleoprotein (NP) of the Crimean-Congo hemorrhagic fever virus (CCHFV) plays a critical role in viral replication and immune recognition, making it a promising target for vaccine development. This study aimed to design and evaluate a multiepitope recombinant DNA vaccine targeting the NP of CCHFV. Methods: Cytotoxic T lymphocyte (CTL) epitopes from the NP were predicted via immunoinformatics approaches and systematically assessed for antigenicity, allergenicity, toxicity, hydrophobicity, and global population coverage. The selected epitopes were incorporated into four DNA vaccine constructs driven by a cytomegalovirus promoter, adjuvanted with human β-defensin 3 (hBD3), and fused to the reporter protein mRuby3. The constructs were evaluated in vitro using a fluorescent reporter system designed to provide a readout of TCR signaling upon the co-culture of T lymphocytes with differentiated monocytic cells expressing antigens. In vivo immunogenicity and protective efficacy were assessed in BALB/c (exploratory pilot) and IFNAR^−/− mice, a highly susceptible model for viral infection. Cytokine responses were measured to assess immunogenicity. Results: In vitro assays showed predominantly antigen-independent T-cell activation, suggesting that nonspecific stimulation inherent to the reporter co-culture system likely obscured the detection of antigen-specific TCR signaling. In vivo analyses in BALB/c mice revealed that the constructs elicited only modest systemic cytokine profiles while CCHFV-specific IgG and IFN-γ secretion remained undetectable, indicating that antigen-specific T-cell and antibody responses were limited. In the IFNAR^−/− challenge model, several peptide groups achieved significant 2–3 log reductions in tissue viral RNA and infectious titers (p < 0.05 vs. sham). However, the observed viral modulations were insufficient to reach the protective threshold and did not translate to a survival benefit (0%). Conclusion: Despite a rational in silico foundation, the multiepitope DNA vaccine constructs demonstrated limitations in inducing potent, antigen-specific immunity across both mouse models. The lack of antigen-specific responses indicates limitations in epitope selection, construct design, and delivery strategies, requiring optimization of next-generation epitope-based vaccines. These findings highlight the complexity of translating computational epitope predictions into functional vaccines, and provide benchmark data as a framework to guide future optimizations. Full article

Background: Biliary tract cancer (BTC) is an aggressive malignancy with limited therapeutic options and a poor prognosis. CD73 is upregulated under hypoxic conditions and promotes tumor progression. However, its clinical role in BTC and interaction with tumor-infiltrating lymphocytes (TILs) remain unclear. This study aimed to elucidate the association between CD73 expression and prognosis in BTC, as well as its impact on the tumor microenvironment (TME) and TILs. Methods: This retrospective study included 100 patients who underwent curative BTC surgery at Hokkaido University Hospital between 2018 and 2023. Formalin-fixed tumor specimens were analyzed using DeepPathFinder™ (biomy Inc., Tokyo, Japan), an AI-based digital pathology platform enabling objective quantification of CD73 expression and lymphocyte infiltration within tumoral (T) and stromal (S) compartments. Immunohistochemistry for CD3, CD8, Foxp3, and CD163 was used to identify T-cell subsets and macrophages. Associations between CD73, TIL subsets, and overall survival (OS) were assessed using the Kaplan–Meier, Cox regression, and Spearman correlation analyses. Results: High T-CD73 expression was associated with shorter OS (hazard ratio [HR] = 1.97, p = 0.041), whereas S-CD73 showed no prognostic relevance. Conversely, high S-TIL density was correlated with improved survival (HR = 0.49, p = 0.032). T-CD73 expression was negatively correlated with stromal CD3⁺ and CD8⁺ T-cell densities, indicating selective suppression of stromal cytotoxic T-lymphocyte (CTL) infiltration. No significant correlations were observed between Foxp3⁺ T cells and CD163⁺ M2 macrophages. Conclusions: CD73 upregulation in tumor cells impairs stromal CTL and TIL activity, leading to a poor prognosis. Spatial distribution, rather than total TIL number, better reflects effective anti-tumor immunity. Full article

We prospectively evaluated whether cytotoxic T-lymphocyte (CTL) activation and T-cell receptor (TCR) Vβ clonality predict treatment-free remission (TFR) after tyrosine kinase inhibitor (TKI) cessation in chronic-phase chronic myeloid leukemia (CML). Forty-five patients with sustained deep molecular response (DMR) were enrolled (On-TKI, n = 38; Off-TKI, n = 7) and underwent one-year immuno-monitoring from consent. The primary endpoint was 12-month TFR, defined as retention of MR4. Overall, 32/45 patients (71%) maintained TFR at 12 months. Longer TKI exposure and stable DMR were associated with TFR; notably, patients fulfilling “≥7 years of TKI plus ≥1 year of DMR” and exhibiting CTL activation features—CD8 > CD4, memory > effector, and/or highly activated CTL clones on TCR Vβ repertoire—showed the highest likelihood of durable TFR. By contrast, NK cells, effector Tregs, and G-/M-MDSCs did not discriminate TFR status in this cohort. Although antigen specificity against CML stem cells was not directly tested, the memory-dominant CTL phenotype is consistent with immune control after antigen reduction. These findings suggest that a simple, clinically accessible strategy based on flow cytometric CTL profiling and TCR Vβ clonality may help inform TKI discontinuation decisions in CML. External validation is warranted to confirm transportability and refine clinical thresholds. Full article

As SARS-CoV-2 continues to evolve with increased transmissibility and immune evasion, the need for vaccines that provide broader and more durable protection has become increasingly urgent. The extensive research spurred by the pandemic has accelerated the development of diverse vaccine platforms, including mRNA, DNA, virus-like particles (VLPs), recombinant proteins, and mosaic mono- and polyvalent vaccines. While several of these platforms have reached regulatory approval and widespread clinical employment, others remain under evaluation or in various stages of clinical development. These vaccines have significantly reduced infection rates, severe disease, and hospitalizations, particularly among high-risk group. Nevertheless, the ongoing emergence of novel variants and subvariants has challenged the efficacy of both existing and newly developed vaccines. This evolving landscape underscores the urgent need for a universal SARS-CoV-2 vaccine platform capable of providing comprehensive and long-lasting immunity. In this review, we evaluate current and emerging strategies for SARS-CoV-2 universal vaccine development, with a focus on antigen design, breadth of immune protection, and clinical feasibility. Attention is given to various universal vaccine platforms such as the mosaic polyvalent spike construct, multi-epitope vaccines targeting the receptor-binding domain (RBD), and approaches centered on the conserved S2 subunit of the spike protein. We also discuss strategies leveraging additional conserved viral proteins and T helper (Th) and cytotoxic T lymphocyte (CTL) epitopes from across coronaviruses. By highlighting the advances in these areas, this review provides a framework to guide the rational design of next-generation universal vaccines capable of delivering broad and durable protection against SARS-CoV-2 variants. Full article

Invariant natural killer T (iNKT) cells are a unique lymphocyte subset that bridge innate and adaptive immunity through recognition of glycolipid antigens presented by CD1d. Upon activation by ligands such as α-galactosylceramide (α-GalCer), iNKT cells rapidly secrete cytokines, including IFN-γ and TNF-α, thereby activating dendritic cells, natural killer (NK) cells, and cytotoxic T lymphocytes (CTLs) to promote antitumor immunity. Despite their therapeutic promise, clinical translation has been limited by rapid α-GalCer clearance, induction of iNKT cell anergy following repeated stimulation, and the immunosuppressive tumor microenvironment (TME). Recent advances in lipid-engineered nanoparticle systems offer solutions to these challenges by improving ligand stability, enhancing antigen-presenting cell targeting, and enabling controlled release that sustains Th1-biased activation while reducing anergy. Liposomal and polymer-based nano-formulations enhance bioavailability and promote more durable IFN-γ-mediated responses. In parallel, chimeric antigen receptor (CAR)-engineered iNKT cells provide antigen-specific tumor targeting while preserving intrinsic CD1d-restricted immunomodulatory functions, demonstrating encouraging safety and efficacy in early-phase studies. Combination strategies further strengthen iNKT-based immunotherapy. Integration with chemotherapy, immune checkpoint inhibitors such as anti-PD-1 and anti-CTLA-4, and cytokine support enhances effector activation, counteracts TME-induced suppression, and improves therapeutic outcomes. However, challenges remain, including optimization of dosing, control of off-target immune activation, scalable manufacturing, and long-term safety evaluation. Collectively, the convergence of nanotechnology, CAR engineering, and rational combination approaches establishes iNKT cell-based therapy as a promising next-generation immunotherapeutic strategy. Continued refinement of delivery systems, genetic engineering platforms, and translational protocols may enable durable immune reprogramming and improved clinical outcomes in resistant and immunosuppressive cancers. Full article

Influenza’s pandemic threat is driven by antigenic drift, which limits the efficacy of conventional vaccines. To address this challenge, we established a clinical serum-anchored computational design pipeline for a broad-spectrum multi-epitope mRNA vaccine (MEMV), bridging the gap between pure in silico design and clinical applicability. Using 36 longitudinal sera (d0/d28/d365) from 12 well-characterized human cohorts (6 vaccine recipients and 6 influenza patients) and high-density antibody-peptide microarrays, we empirically identified 12 immunodominant B-cell linear epitopes from the nucleoprotein (NP) of influenza A (H1N1/H3N2) and B viruses. These experimentally validated epitopes were combined with in silico-predicted conserved helper T-lymphocyte (HTL)/cytotoxic T-lymphocyte (CTL) epitopes (from NP/HA/NA) to construct MEMVs candidates, ensuring high antigenicity, non-toxicity, and 95.63% global HLA coverage. Molecular docking and 100 ns molecular dynamics (MD) simulations confirmed favorable conformational compatibility between MEMVs and Toll-like receptor 3 (TLR3) in silico immunization via C-ImmSim predicted robust B/T-cell responses and protective cytokine (IFN-γ/IL-10) production. Collectively, this pipeline shortens the preliminary design cycle for influenza vaccines, provides a standard epitope-combination strategy, and offers direct targets for follow-up in vitro/in vivo experiments. Full article