Search Results (1,235)

Objective: We aimed to elucidate the epidemiological characteristics and co-infection status of HBoV in Guangzhou and to investigate the potential recombination events and alterations in antigenic properties among circulating HBoV strains. Methods: Utilizing respiratory specimens collected from patients at sentinel surveillance hospitals in Guangzhou between August 2023 and December 2025, multiplex pathogen detection was performed. We describe the temporal and demographic distribution of HBoV in Guangzhou and determine its co-infection patterns. Subsequent sequence analysis focused on identifying potential recombination events and characterizing antigenic properties. Results: The epidemiological features of HBoV in Guangzhou exhibited a primary epidemic peak around the autumn season, followed closely by a secondary peak. HBoV infection was predominantly observed in children under three years of age. Co-infections with rhinovirus and parainfluenza virus were common. Whole-genome sequencing yielded 15 complete HBoV genome sequences. Recombination analysis and verification suggested potential recombination events in two of these sequences. A comparative analysis of the antigenic characteristics of one identified recombinant strain, GZ-2024-20891, against its putative parental strains and domestic prevalent strains revealed potential alterations in its antigenic characteristic. Conclusions: Bocavirus is highly prevalent among young children under 3 years of age, with a secondary peak following the main epidemic peaks around autumn in Guangzhou. Genetic recombination and potential antigenic alteration were detected in bocavirus. Full article

A capacitive screen-printed electrode immunosensor operating in non-faradaic mode by dispensing redox probes was developed for the Coronavirus 2 Spike (S) protein. This new strategy enabled direct detection of the S protein by measuring changes in the electrochemical capacitance resulting from antigen–antibody interactions on the electrode surface, altering interfacial dielectric properties. To enhance analytical sensitivity and provide an electrode surface with attractive capacitive and conductive properties, an in-house graphite ink-based screen-printed electrode was developed and subsequently modified with a polypyrrole (PPy) layer in bulk-synthesized in the presence of Cetyltrimethylammonium bromide (CTAB). CTAB acted as a dispersing and structure-directing agent, promoting homogeneous distribution and guiding the PPy polymerization, resulting in a composite with improved charge density storage and high conductivity. Analytical signals of the S proteins in spiked serum were detected by measuring the Specific Capacitances taken from cyclic voltammograms. This capacitive immunosensor achieved a linear range from 1 to 100 µg/mL (R² = 0.989, p < 0.05), with a limit of detection of 0.45 µg/mL of S protein, which falls within the clinical range for COVID-19 diagnostics. Probe-free detection without ferri/ferrocyanide steps minimizes errors by probe adsorptions and is easy to use as a point-of-care, unlike conventional immunosensors. Full article

Dengue is an arboviral disease of global significance caused by Orthoflavivirus denguei (DENV), which has four antigenically distinct serotypes. The envelope (E) protein plays a critical role in viral entry and eliciting immune responses. This study aimed to compare the biochemical and immunological properties of the E protein across the four DENV serotypes using in silico approaches. E protein reference sequences were retrieved from RefSeq and analyzed with various bioinformatics tools. Sequence alignment revealed identities ranging from 63.08% to 77.69%. Biochemical analysis showed minimal variation in molecular weight and isoelectric point; however, the net charge of DENV-3 E protein was notably lower. Secondary structure predictions indicated a predominance of alpha-helices in DENVs-1/2, while DENVs-3/4 featured more beta-sheets. Post-translational modification analysis revealed mostly casein kinase II phosphorylation sites across all serotypes, with DENV-4 uniquely presenting also tyrosine kinase sites. Amino acids W231/D341 in DENV-1, Q86 in DENVs-2/4, and D87/D339 in DENV-3 showed maximum antigenicity scores in B cell recognition, while the human leukocyte antigen (HLA) alleles B*08:01/B*39:01 and DRB4*01:01, recognized by T cells, presented the highest number of predicted epitopes for the different DENV serotypes. Conservation analysis showed that the major antigenic regions highlighted in this study are highly conserved among contemporary DENV isolates despite the genetic variability observed within each serotype. These findings suggest that subtle structural differences in the E protein may contribute to distinct immunogenic profiles, highlighting candidate regions for future investigation. Full article

Hepatocellular carcinoma (HCC) is sustained by coordinated interactions among malignant hepatocytes, immune cells, and stromal populations that collectively drive tumor growth, immune evasion, and vascular remodeling. Using integrative single-cell transcriptomics on 93,032 cells from tumor and healthy human liver, we characterized cell-type-specific transcriptional programs underlying immunometabolic reprogramming and reconstructed the intercellular communication circuits that maintain the tumor microenvironment. Malignant hepatocytes displayed upregulation of genes encoding both glycolytic and oxidative phosphorylation (OXPHOS) metabolic enzymes, consistent with metabolic plasticity, while concurrently suppressing genes involved in antigen presentation—a transcriptional pattern indicative of coordinated metabolic and immune-evasive reprogramming. Tumor-associated macrophages acquired TREM2-enriched, lipid-handling phenotypes consistent with immunosuppressive polarization, and tumor endothelial cells upregulated angiocrine and extracellular matrix programs while silencing innate immune outputs. Ligand–receptor inference revealed a qualitative rewiring of intercellular communication: the antigen-presentation-centered network of the healthy liver was replaced by a tumor-driven architecture dominated by pro-angiogenic, ECM–integrin, inflammatory chemokine, and lipid-associated signaling circuits, with malignant hepatocytes, TAMs, and TECs collectively assuming the dominant signaling burden. These findings establish that HCC progression is an emergent property of a stabilized multicellular network, rather than the autonomous behavior of malignant cells, and define cooperative immunometabolic modules that constitute tractable targets for combinatorial therapeutic intervention. Full article

The magnitude and quality of adaptive immune responses are fundamentally influenced by the efficiency of antigen presentation. Traditional vaccine platforms, such as live–attenuated or inactivated pathogens, although immunogenic, often present safety concerns. Conversely, subunit vaccines, despite being safer, generally exhibit poor immunogenicity due to inadequate delivery of antigens to professional antigen–presenting cells (APCs). To address this issue, the development of innovative delivery systems has become a pivotal strategy to overcome significant biological barriers, including extracellular antigen degradation, suboptimal lymph node targeting, and inefficient cross–presentation necessary for CD8+ T cell activation. This review systematically explores recent advancements in delivery technologies aimed at enhancing antigen presentation, encompassing rationally engineered nanocarriers and sophisticated biomimetic platforms. We first examine how nanoparticle properties like size, surface charge, and ligand density affect intracellular trafficking and the transition from MHC–II to MHC–I cross–presentation. Then, we explore bioinspired systems such as extracellular vesicles, virus–like particles, and cell–membrane–coated nanoparticles that utilize natural biological traits for enhanced targeting and immune modulation. Additionally, we review new physical delivery methods like microneedle arrays and in situ electroporation for direct, minimally invasive antigen delivery to dendritic cells. Lastly, we discuss the potential of these platforms in personalized cancer vaccines and combination immunotherapies. By combining insights from materials science, immunology, and bioengineering, these next–generation delivery tools could enhance antigen presentation and transform precision vaccination and immune intervention. Full article

Vaccination remains one of the most effective strategies for preventing infectious diseases. Yet, the success of modern vaccines increasingly depends on the rational design of adjuvants that enhance and shape immune responses. In this review, we examine current and emerging adjuvant strategies for viral vaccines across the human lifespan. Traditional adjuvants, particularly aluminum salts, have long served as the foundation of vaccine formulations. Still, their limitations have driven the exploration of novel platforms, including emulsions, nucleic acid-based adjuvants, and advanced particulate delivery platforms with intrinsic immunostimulatory properties. These newer approaches act through diverse mechanisms, such as activating innate immune pathways via pattern recognition receptors (PRRs) and stimulating antigen-presenting cells (APCs), thereby improving both humoral and cellular immunity. Recent advances in molecular biology, nanotechnology, and systems vaccinology have deepened mechanistic understanding and enabled more precise modulation of immune responses. However, significant challenges remain, including incomplete knowledge of adjuvant mechanisms, limited diversity among licensed adjuvants, safety concerns, and inconsistent efficacy across age groups. In particular, immune immaturity in infants and immunosenescence in older adults highlight the need for age-specific adjuvant strategies. The review identifies critical gaps in comparative studies, long-term safety data, and the development of adjuvants capable of inducing broad and durable immunity. Further, this article integrates licensed and emerging viral vaccine adjuvants through a lifespan framework. Addressing these limitations through interdisciplinary research and precision-based approaches will be essential for advancing next-generation vaccines and improving global preparedness for emerging infectious diseases. Full article

Single-domain antibodies (sdAbs) are the smallest antigen-binding antibody (Ab) fragments (12–15 kDa) and have emerged as a versatile therapeutic platform. Their compact size, high solubility, stability, and ability to access cryptic epitopes distinguish them from conventional monoclonal Abs (mAbs) and larger Ab fragments. These properties are particularly attractive in ophthalmology, where molecular size, tissue penetration, and formulation constraints critically influence therapeutic performance. This narrative review summarizes the structural features, engineering strategies, immunogenicity considerations, and production platforms of sdAbs, with a focus on ocular applications. Preclinical studies demonstrate promising efficacy in retinal vascular diseases through targeting of VEGFA, ANG2, TNFα, and complement components, as well as in inflammatory and anterior segment disorders. SdAbs can be formatted as multimeric or Fc-fused constructs to extend intraocular half-life or delivered via gene therapy vectors as a sustained intraocular “biofactory” approach. Notably, recent work demonstrates the feasibility of vector-encoded sdAbs targeting complement C3 in vivo. While challenges remain regarding immunogenicity, pharmacokinetics, and regulatory pathways, the approval of several sdAb-based drugs in other fields underscores their clinical potential. SdAbs represent a promising next-generation modality for ocular therapeutics, enabling innovative strategies beyond conventional antibody formats. Full article

Systemic administration of antibodies that target immune checkpoint inhibitor pathways is a highly effective approach to cancer immunotherapy, but systemic toxicity can limit clinical utility. In preclinical testing, a peri-tumor injection of a low dose of hydrogel-encapsulated cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) antibody was shown to selectively activate T cells in tumor-draining lymph nodes, induce tumor infiltration by cytotoxic T cells, and result in tumor regression, protective immunity, and long-term survival. In contrast to systemic therapy, there was limited systemic exposure or risk for autoimmune toxicity. The current study focuses on translating this platform into a biocompatible human therapeutic. The hydrogel matrix was reformulated using a low-molecular-weight hyaluronic acid. A recombinant human hyaluronidase (rHuPH20) was incorporated to promote lymph node targeting and self-resorbing features. Formulations were optimized to operate at neutral pH and with gelation kinetics allowing a 5 to 10 min administration window. Performance features were assessed including the capacity to encapsulate human IgG or ipilimumab antibody at proposed therapeutic doses (1–15 mg/mL), impact of rHuPH20 and antibody on rheologic properties and three-dimensional microstructure, and payload delivery profiles in vitro and in vivo. Results confirm the capacity for this unique hydrogel platform to be adapted for human testing. Full article

Lyssaviruses are neurotropic viruses that cause fatal encephalitis, with the rabies virus as the most prominent member. The viral glycoprotein (G) plays a key role in infection and is the main target of adaptive immune responses. This study aimed to comparatively analyze linear B- and CD4⁺ T-cell epitopes in the G protein ectodomain of lyssaviruses from phylogroups I (RABV, EBLV-1, EBLV-2, DUVV, and ABLV) and II (LBV and MOKV) using bioinformatics tools. Protein sequences were obtained from GenBank, processed to isolate ectodomains, aligned for identity analysis, and used to generate consensus sequences. CD4⁺ T-cell epitopes were predicted based on HLA-II binding affinity, while linear B-cell epitopes were identified using physicochemical properties and assessed for N-glycan masking. Amino acid identity ranged from 76.71% to 83.79% in phylogroup I and 82.72% in phylogroup II. Phylogroup I showed a higher density of HLA-II epitopes (0.22) than phylogroup II (0.18). Despite differences in antigenicity distribution, conserved linear B-cell epitopes in both phylogroups overlapped with peptides binding to HLA-II DRB1*15:01 and were not masked by N-glycans. These findings highlight putatively conserved antigenic regions identified through computational analysis and may support future studies focused on the development of improved vaccines and immunoprophylactic strategies against lyssaviruses. Full article

The heterogenous mesenchymal stem/stromal cells (MSCs) express the surface antigens associated with distinct cell subpopulations. CD271, characteristic of stem cells derived from the neural crest, could indicate cells with a unique phenotype. The study examined whether the CD271+ subpopulation characterized by better stem and neural properties than the heterogeneous MSC population. The initial Wharton jelly-derived MSCs (WJ-MSCs) population was divided into two subpopulation: CD271-positive (WJ-MSC-CD271+) and CD271-negative (WJ-MSC-CD271−) with Fluorescence-Activated Cell Sorting (FACS). We compared the clonogenic potential and neural marker expression under standard culture conditions and in the presence of nerve tissue components—cerebrospinal fluid (CSF) or nerve tissue fragments (hippocampus). FACS allowed the enrichment of CD271+ cells from 1% to approximately 50%. WJ-MSC-CD271+ is characterized by significantly more self-renewal cells and increased expression of neuronal genes than WJ-MSC-CD271−. Under co-culture with CSF or hippocampal fragments, WJ-MSC-CD271+ contained more cells expressing Β-III-tubulin as well. Finally, we reported that stimulation with epithelial growth factor (EGF) and basal fibroblast growth factor (bFGF) enhanced CD271+ numbers in the initial population and stabilized them in further cell culture. WJ-MSC-CD271+ cells showed improved potential for differentiation into neural progenitors, although further research is needed for their potential use in neurological diseases. Full article

Serum albumin (SA) plays a fundamental role in the transport of metabolites and endogenous ligands. Additionally, animal albumins are potent allergens. Heterologous expression of SAs is challenging due to their complex structure. In this study, we describe a simple method for enhanced production of soluble and functional recombinant feline (rFel d 2) and canine (rCan f 3) albumins in the standard E. coli strain BL21 (DE3). To achieve this, the 18-amino acid signal peptide was removed from the N-terminus of each albumin. To improve expression, folding, and solubility of recombinant proteins, we tested an extended panel of fusion proteins. Among them, MBP (maltose-binding protein), TF (trigger factor), and NusA (E. coli transcription termination factor) allowed the production of soluble fusion forms of rFel d 2 and rCan f 3. To confirm the structural integrity of the products, we analyzed the IgE-binding characteristics of recombinant versus native albumins. rFel d 2 and rCan f 3 fused with TF, MBP, and NusA bound albumin-specific immunoglobulin E (in 26/33, 29/33, 31/33, and 27/29, 26/29, 27/29 cases, respectively, comparable to native Fel d 2 and Can f 3. Thus, removal of the signal peptide combined with fusion partners enables expression of Fel d 2 and Can f 3 in E. coli with preserved antigenic properties. Full article

Macrophage-derived extracellular vesicles (EVs) have emerged as promising biomimetic platforms for targeted cancer drug delivery due to their biocompatibility, immune-modulatory properties, and tumor-homing capabilities. Among macrophage subtypes, M1-polarized macrophages exhibit potent anti-tumor functions characterized by pro-inflammatory cytokine secretion, improved antigen presentation, and the ability to remodel the tumor microenvironment (TME). Utilizing these properties, M1-polarized macrophage-derived EVs serve as cell-free therapeutic systems capable of delivering bioactive cargo while simultaneously promoting anti-tumor immune responses. However, the clinical application of natural EVs is limited by low yield, heterogeneity, and challenges in large-scale production. Artificial nanovesicles (ANVs) have been developed to address these limitations, offering improved scalability, compositional control, and reproducibility. This review provides an overview of macrophage differentiation and polarization, with a focus on the immunological profile and anti-tumor mechanisms of M1-polarized macrophages. It further discusses current methodologies for EV isolation and ANV generation, along with cargo loading strategies that balance encapsulation efficiency and vesicle stability. In addition, this review also emphasizes their targeting approaches, cellular uptake pathways, and the intracellular trafficking mechanisms that influence delivery efficiency and therapeutic outcomes. Key challenges, including standardization, biological barriers, and functional consistency, are critically evaluated. Emerging strategies that integrate vesicle engineering with personalized medicine underscore the potential of these systems to advance precision oncology. Full article

The non-collagenous domain 1 of the α3 chain of type IV collagen (α3(IV)NC1) is the primary autoantigen in anti-glomerular basement membrane (anti-GBM) disease. We previously developed a modified antigen-specific peptide, m-P14, derived from the nephritogenic epitope α3_127–148, which ameliorated experimental anti-GBM nephritis. However, its short half-life limits clinical translation. This study evaluated a butyrate-conjugated derivative (m-P14-BA) to improve pharmacokinetic properties while preserving therapeutic efficacy. M-P14-BA and m-P14 were administered to α3_127–148 immunized Wistar Kyoto rats in early and late treatment settings. Renal injury parameters and intrarenal inflammation were assessed, and pharmacokinetic profiles were evaluated following intraperitoneal administration in beagle dogs. M-P14-BA reduced proteinuria, crescent formation, glomerular IgG deposition, complement activation, and inflammatory cell infiltration, with overall efficacy comparable to m-P14 in early treatment settings. In late treatment settings, m-P14-BA was associated with a significant improvement in blood urea nitrogen levels and modest reductions in proteinuria and histopathological injury. Butyrate conjugation markedly improved pharmacokinetics, prolonging plasma elimination half-life by approximately 2.8-fold and increasing systemic exposure nearly fourfold. These pharmacokinetic improvements were associated with maintained therapeutic efficacy at a reduced dose, with 10 mg/kg m-P14-BA achieving effects broadly similar to those observed with 30 mg/kg m-P14. In summary, butyrate conjugation improves the pharmacokinetic profile of an antigen-specific therapeutic peptide while preserving therapeutic activity, suggesting a potential strategy to enhance the translational feasibility of peptide-based immunotherapy in anti-GBM disease. Full article

C-reactive protein (CRP) is one of the most essential biomarkers for the early detection of inflammation and infection. In this study, we developed a sensitive and selective electrochemical immunosensor for CRP detection, leveraging the unique properties of gold nanoparticles (AuNPs). A nanostructured layer of AuNPs was deposited onto a screen-printed carbon electrode (SPCE), followed by the formation of a self-assembled monolayer (SAM) of L-cysteine and EDC/sulfo-NHS chemistry. The antibody was covalently immobilized onto the modified electrode through optimized dual-crosslinking chemistry. Detection conditions were systematically optimized, with pH 8.0 in Tris buffer providing the best electrochemical response. Electrochemical characterization was performed using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and differential pulse voltammetry (DPV) in a 5 mM K₃[Fe(CN)₆]/K₄[Fe(CN)₆] redox probe solution containing 0.1 M KCl. CRP detection was achieved by monitoring the increase in charge transfer resistance (Rct) upon specific binding of the target CRP antigen to the immobilized antibody. Spiked recovery experiments showed spiked recovery rates ranging from 98.01% to 107.14%, with a standard deviation below 4%. Regeneration studies demonstrated high efficiency, confirming the suitability of the sensor interface for repeated and reliable measurements. Under optimized conditions, the immunosensor exhibited excellent analytical performance, including a low limit of detection (LOD) of 0.16 µg/mL, a wide linear detection range of 5–100 µg/mL, high selectivity against 13 potential interferents (including inflammatory cytokines), and good reproducibility with a relative standard deviation (RSD) of 3.69%. The sensor also showed strong stability, retaining more than 95% of its signal after 15 days, and high regeneration efficiency of 97% over seven cycles. These results highlight the strong potential of the proposed immunosensor for point-of-care (POC) applications due to its simple fabrication, cost-effectiveness, user accessibility, and robust analytical performance. Full article

Background. The highly mutable influenza virus causes severe annual infections worldwide and results in substantial socioeconomic losses. The spread of infection could be effectively controlled by cross-protective vaccines and universal diagnostic test systems based on the nucleoprotein (NP) as one of the most conserved viral antigens. However, NP also undergoes slow evolutionary changes, and little is known about the influence of these mutations on its antigenicity and immunogenicity. Methods. We expressed the full-length recombinant 6xHis-tagged NPs of ten evolutionary distant influenza A strains of different subtypes in E. coli BL21(DE3) cells and purified these proteins by immobilized metal affinity chromatography. The obtained antigens were identified by mass spectrometry and serological methods. NPs served as antigens for three immunizations of BALB/c mice (15 µg/animal at 14-day interval) and as capturing proteins in ELISA at 2 µg/mL, in order to study the effect of adaptive mutations on the antigenic and immunogenic properties of NPs. Results. A pronounced cross-reactivity of anti-NP antibodies induced in mice by immunization with different NPs was revealed. At the same time, we observed the differences in the humoral immunogenicity of NP, which are in line with the accumulation of evolutionarily driven NP mutations. In general, antibody affinity to heterologous NPs was reduced, indicating the differences in the specificity of anti-NP immunoglobulins, which may be caused by evolutionarily determined variability of immunogenic epitopes leading to the emergence of escape mutations. Conclusions. Overall, our results reflect the slightly evolving nature of the NP antigen, which influences the specificity spectrum of anti-NP antibodies and should be considered as a limitation for the development of NP-based cross-protective vaccines and test systems. Full article