Search Results (1,390)

We propose a dimensionally consistent fractional spatio-temporal PDE framework for modelling immune-mediated demyelination in multiple sclerosis (MS). The system couples effector and regulatory T cells, M1/M2 macrophage polarisation, pro- and anti-inflammatory cytokines, oligodendrocyte dynamics, and time-dependent therapeutic controls within a unified distributed-parameter structure. In contrast to ad hoc replacements of integerorder derivatives by Caputo fractional derivatives, the fractional extension proposed here is derived from an underlying continuous-time random walk (CTRW) process with Mittag–Leffler-distributed residence times. This stochastic derivation yields a governing system in which a single commensurate fractional order α ∈ (0, 1], together with a characteristic memory timescale τ0, ensures dimensional consistency and mass balance across all coupled components. The model is formulated as a system of nonlinear reaction–diffusion equations with cross-regulatory and multiplicative interaction terms governing immune amplification, cytokine feedback, and the demyelination–remyelination balance. Analytical interpretation shows how non-Markovian residence times induce Mittag–Leffler-type relaxation and thereby modify effective growth, decay, and stability properties. Numerical simulations compare classical and fractional dynamics, revealing that memory-driven kinetics prolong effector T-cell and M1-macrophage activity, attenuate reparative M2 and oligodendrocyte responses, and extend the effective action of bang–bang therapy inputs representing IFN-β and glatiramer acetate beyond their dosing windows. The results indicate that integer-order models may underestimate chronic inflammatory persistence and demyelination severity, while providing a mathematically and physically well-posed platform for memory-aware immune modelling and therapy evaluation in MS. Full article

Natural bioactive polysaccharides have been investigated for their ability to modulate antiviral immune responses. Polysaccharide peptide (PSP) from Coriolus versicolor previously restricted human immunodeficiency virus type 1 (HIV-1) entry into monocytic cells through a protein kinase R (PKR)-dependent cytoskeletal mechanism. However, its impact on antiviral signaling in adaptive cluster of differentiation 4 (CD4)+ T-cell models remains incompletely defined. Here, we evaluated concentration- and time-dependent effects of PSP (50–1000 µg/mL) in Jurkat T cells over 3 and 6 days. Cell viability was assessed by MTT, trypan blue exclusion, and viable cell density analysis. Immunoblotting and reverse transcription quantitative polymerase chain reaction (RT-qPCR) were performed to examine Toll-like receptor 4 (TLR4), nuclear factor kappa B (NF-κB), signal transducer and activator of transcription 1 and 2 (STAT1/STAT2), PKR, interferon gamma (IFN-γ), and cofilin-1 signaling. PSP did not induce cytotoxicity at any concentration. Instead, PSP promoted dose- and time-dependent upregulation of intracellular TLR4, PKR, phospho-PKR (Thr446), Cofilin-1, phospho-Cofilin-1 (Ser3), phospho-STAT1 (Tyr701), phospho-STAT2 (Tyr690), phospho-NF-κB (Ser536), and IFN-γ, with amplified responses at Day 6. These changes were paralleled by transcriptional induction of antiviral-associated genes. Collectively, PSP induces coordinated interferon (IFN)-associated and cytoskeletal regulatory signaling in Jurkat T cells without cytotoxicity, providing a mechanistic framework for future evaluation of viral permissiveness and antiviral responses in adaptive immune models. Full article

Alphaviruses are mosquito-borne viruses that can infect the central nervous system (CNS) and cause encephalomyelitis, which is a rare but dangerous complication from infection. In mice, this can be studied in a model of infection with Sindbis virus (SINV), which infects neurons and causes neurological disease. Due to the non-renewable nature of neurons, the immune response in the CNS is specialized to prevent neuronal damage or death, even if they are infected. Therefore, insights into the nuances of antiviral immunity in the CNS provide a better understanding of disease pathogenesis and mechanisms of recovery. Type I interferons (IFNs) are critically important for survival; they are an innate antiviral defense mechanism that consists mainly of IFNα and IFNβ. Although both use the same receptor, type-specific differences between IFNα and IFNβ have been described in other contexts. To this end, Ifnb^−/− mice were used to elucidate the role of IFNβ in recovery from alphavirus encephalomyelitis. IFNβ-deficient mice have intact IFNα expression and downstream signaling, but symptomatic disease occurs earlier and is more severe. This is accompanied by increased virus replication in the early stages of infection. Microgliosis is reduced in Ifnb^−/− mice compared to wildtype, but inflammatory cytokine/chemokine levels are higher and associated with alterations in monocyte and NK cell recruitment into the CNS. Ifnb^−/− mice have no deficiencies in the expression of factors known to be required for viral clearance. Therefore, IFNβ modulates the early stages of the immune response and facilitates restriction of virus replication, contributing to delayed disease onset. Full article

Manganese ions (Mn²⁺) are an essential trace element within organisms spanning the entire tree of life. It has reported that Mn²⁺ exerts strong immunocompetence effects and exhibits antiviral effects against various human and animal viruses, including DNA and RNA viruses. Recently, Mn²⁺ has been found to be involved in the activation of the innate immune DNA-sensing cyclic GMP-AMP synthase (cGAS) stimulator of interferon genes (STING) pathway and subsequent antiviral function. However, the antiviral mechanism of Mn²⁺ remains unclear. In the current study, the results suggest that the cGAS-STING pathway is essential for Mn²⁺ to promote interferon (IFN) signaling, but it is not essential for triggering antiviral functions. After knocking out the STING or interferon regulatory factor 3 (IRF3) gene, Mn²⁺ still retains its antiviral activity against herpes simplex virus type 1 (HSV-1) and vesicular stomatitis virus (VSV). Furthermore, the results from transcriptomic analysis indicate that Mn²⁺ can induce a significant change in the apoptotic process in STING⁻/⁻ 3D4/21 cells. Mn²⁺ can induce cell apoptosis through the oxidative stress pathway, and inhibiting the apoptotic signal could suppress Mn²⁺-mediated antiviral activity in STING⁻/⁻ 3D4/21 cells. Additionally, dual knockout of IRF3 and caspase3, resulting in concurrent loss of IFN and apoptotic signals, eliminates the antiviral effects of Mn²⁺. In summary, the current study suggests that Mn²⁺ could exert antiviral effects not only through the cGAS-STING-IFN pathway but also via the reactive oxygen species (ROS)-apoptosis pathway. Full article

Orf virus (ORFV) is a globally distributed zoonotic parapoxvirus that causes a highly contagious mucocutaneous disease in small ruminants. Despite the urgent demand for vaccination-based control, no licensed vaccines are currently available universally. In this study, we generated two recombinant Sendai virus (SeV) vectors expressing ORFV 011 (rSeV-GFP-B2L) and ORFV 059 (rSeV-GFP-059) genes and evaluated their ability to stimulate antiviral responses in vitro. Following the transduction, we assessed transgene expression, innate immune activation, induction of interferon-stimulated genes (A3Z1, OBST2, SAMHD1), and antiviral activity. Both vectors significantly upregulated pattern recognition receptors (TLRs, RIG-I) and type I interferon (IFN-β) genes, with rSeV-GFP-059 inducing the strongest response. Remarkably, OBST2 was robustly upregulated, suggesting a potential role in restricting ORFV replication. Antiviral activity assays revealed a marked reduction in ORFV DNA copies and a mild decrease in ORFV RNA transcription in rSeV-GFP-059-transduced cells, particularly at later time points, accompanied by complete abrogation of the typical cytopathic effect. Collectively, these results demonstrate that SeV-based vectors, particularly rSeV-GFP-059, efficiently prime antiviral immunity and suppress ORFV replication, establishing a promising platform for further in vivo vaccine evaluation in sheep. Full article

Lyme disease (LD) is classically defined as a tick-borne infection caused by Borrelia burgdorferi sensu lato (Bbsl). However, accumulating evidence indicates that, beyond microbial persistence, Bbsl infection can initiate sustained immune dysregulation and post-infectious inflammatory phenotypes in a subset of patients. This narrative review integrates open-access experimental, translational, and clinical data and discusses LD within the spectrum of infection-triggered, immune-mediated processes. We review key immunopathogenic mechanisms, including dysregulated innate immune activation, type I interferon (IFN-I) signaling, T helper 1 and T helper 17 (Th1/Th17) polarization with regulatory T-cell (Treg) insufficiency, antigen persistence (notably borrelial peptidoglycan), and pathways linking infection to autoimmunity such as molecular mimicry, epitope spreading, and human leukocyte antigen (HLA)-restricted susceptibility. These mechanisms are integrated with immune-mediated clinical manifestations affecting the central nervous system (CNS), peripheral nervous system (PNS), musculoskeletal system, heart, skin, and hematologic compartment. Finally, we discuss translational implications for diagnosis, biomarker-guided stratification, and emerging therapeutic strategies that extend beyond antimicrobial therapy, while addressing current controversies and limitations. This framework supports a mechanistic model in which Lyme disease-associated morbidity in selected patients reflects persistent immune activation and dysregulated host responses triggered by infection. Full article

Type 1 diabetes (T1D) is an immune-mediated disease characterized by progressive autoimmune destruction of pancreatic β cells. Although traditionally viewed as primarily T-cell-driven, B cells play essential roles in disease pathogenesis. In addition to producing islet autoantibodies, B cells contribute to immune activation through antigen presentation and cytokine secretion, thereby shaping autoreactive T-cell responses. The earliest clinical predictor of T1D is the appearance of islet autoantibodies in the blood, reflecting a breach in B-cell tolerance well before symptomatic disease onset. In individuals at high genetic risk, type I interferon (IFN) signatures are detectable in peripheral blood prior to seroconversion, suggesting that type I IFNs may act as upstream regulators of B-cell tolerance. Peripheral tolerance is enforced through layered checkpoints including transitional selection, maintenance of anergy, germinal center regulation, and regulatory B-cell differentiation. Studies in systemic autoimmunity demonstrate that type I IFN signaling lowers B-cell activation thresholds, enhances BCR and TLR responsiveness, promotes survival of autoreactive transitional clones via BAFF induction, destabilizes anergy, and skews differentiation toward inflammatory phenotypes such as T-bet+ age-associated B cells. Consistent with this model, single-cell transcriptomic and BCR repertoire analyses in T1D reveal clonal expansion and proinflammatory signatures in islet-reactive B cells during the preclinical stage. Together, these findings implicate the IFN–B-cell axis as a potential target for early disease modification. Full article

The cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) pathway serves as a central innate immune signaling axis in host defense against DNA virus infections, and RNA viruses have also evolved diverse strategies to counteract this pathway. Encephalomyocarditis virus (EMCV), a zoonotic RNA virus, utilizes its 2C protein to antagonize RIG-I-like receptor-mediated type I interferon signaling and induce autophagic degradation of calcium binding and coiled-coil domain 2, thereby evading host antiviral immunity. However, the precise molecular mechanism by which EMCV 2C protein modulates the cGAS-STING pathway remains incompletely understood. Herein, we show that EMCV infection reduces the expression of cGAS and STING proteins, and its 2C protein significantly suppresses the production of IFN-β triggered by poly(dA:dT) or viral infection, as well as the mRNA expression of interferon-stimulated genes. Mechanistically, 2C protein binds to STING via its ATPase domain and facilitates K48-linked polyubiquitination and proteasomal degradation of STING, while dominantly interfering STING translocation to the Golgi apparatus and the formation of STING-TBK1-IRF3 complex, thereby blocking STING-mediated IFN-β signal transduction at multiple levels. This study reveals a novel mechanism by which the EMCV 2C protein suppresses the host antiviral response by targeting STING and promoting its ubiquitination and degradation. This finding deepens understanding of the immune evasion mechanism of EMCV and provides a theoretical foundation for the development of antiviral therapies targeting the 2C protein of picornaviruses. Full article

Cyprinid herpesvirus 3 (CyHV-3) is a pathogen that causes high mortality in common carp (Cyprinus carpio) and koi. Common carp breeding lines with different genetic backgrounds exhibit different resistance levels to viral pathogens. This study aimed to determine the differences in CyHV-3 disease resistance performance between the hybrid offspring (Y × M and M × Y) of the mirror carp ‘Longke 11’ (resistant to CyHV-3) and Yellow River carp, as well as the self-crossed offspring (M and Y). The M, Y × M, M × Y and Y groups were infected with CyHV-3 by immersion. The order of mortality and the duration of death for the four groups of carp were as follows: Y group > Y × M group > M × Y group > M group. Throughout the entire infection stage, the mRNA expression levels of the viral factors thymidine kinase (TK) and open reading frame 72 (ORF72) in the four groups of carp tended to first increase but then decrease. The viral factor expression evaluated on days 30 and 31 post-infection (p.i.), which was the peak of infection mortality, was the highest in the Y group and the lowest in the M group, and compared with the Y × M group, the M × Y group had considerably lower viral gene expression (p < 0.05). The immune-related enzyme activity and content levels of the four carp groups matched the patterns of viral gene expression. On day 29 p.i., a time point with high mortality, the levels of alkaline phosphatase (AKP), glutathione peroxidase (GSH-Px) and total antioxidant capacity (T-AOC) were significantly the lowest in the Y group and significantly the highest in the M group, while the Y × M group showed a significant decrease compared to the M × Y group (p < 0.05). Quantitative real-time (q-PCR) analysis revealed that interleukin-21 receptor (IL21R), interferon regulatory factor 9 (IRF9), interferon type I (IFN-I), interleukin-6 (IL-6) and microtubule-associated protein light chain 3 (LC3), exhibited an initial increase followed by a decrease among the four experimental groups of common carp. In the peak mortality period of carp in the four groups (30 days post-infection), the expression levels of IL21R, IRF9, LC3, and IFN-I were significantly the highest in the M group and significantly the lowest in the Y group, with the mRNA expression of these genes in the M × Y group being significantly higher than that in the Y × M group (p < 0.05). In contrast, IL-6 expression levels exhibited the opposite trend. In this study, the M group exhibited the greatest resistance to CyHV-3, followed by the M × Y group, whose resistance was greater than that of the Y × M group, with the Y group showing the lowest disease resistance. Our findings demonstrate that hybridization modulates resistance to CyHV-3. Furthermore, we identified conserved immune signatures common to both susceptible and resistant carp, including the activation of nonspecific immunity and the upregulation of immune-associated genes. Full article

Horses develop spontaneous tumors, typically in old age. Although local tumor control can be achieved using conventional therapies, systemic therapies are required to treat recurrent and/or metastatic tumors. Immune checkpoint inhibitors, such as anti-PD-L1 antibodies, have been approved for the treatment of various tumor types in humans; however, little is known about the immunosuppressive roles of the PD-1/PD-L1 pathway in horses, and the therapeutic potential of these inhibitors remains to be elucidated. Previously, we reported that the rat monoclonal anti-PD-L1 antibody 6C11-3A11 cross-reacts with horse PD-L1 to block the PD-1/PD-L1 interaction. To further develop antibodies for therapeutic purposes, their immunogenicity must be reduced to maximize efficacy and safety. To this end, we designed an equinized (equine-ized) anti-PD-L1 antibody, Eq6C11, using the complementarity-determining regions of 6C11-3A11. Eq6C11 had antigen-binding properties comparable to those of 6C11-3A11 and inhibited equine PD-L1 binding to PD-1 in a recombinant protein-based assay. Treatment with Eq6C11 significantly increased IFN-γ and IL-2 production in equine peripheral blood mononuclear cell cultures, suggesting its stimulatory activity on T-cell activation. Although further studies are needed to clarify its immunogenicity and clinical activity, these results encourage further development of Eq6C11 as a candidate immune checkpoint inhibitor for cancer immunotherapy in horses. Full article

Bacillus subtilis is aerobic or facultatively anaerobic. After entering the gastrointestinal tract, its spores germinate and colonize the gut, inhibiting the growth of harmful aerobic bacteria (Escherichia coli, Streptococcus, Staphylococcus aureus). However, it remains unclear whether B. subtilis can inhibit Clostridium perfringens type A infection. In this study, B. subtilis PB6 was added to the diets of pregnant sows infected with Clostridium perfringens type A, which significantly improved the reproductive performance and reduced the incidence of bloat in sows and diarrhea in neonatal piglets. The treatment significantly increased the abundance of intestinal probiotics (B. subtilis, Lactobacillus, Limosilactobacillus reuteri, Lactobacillus johnsonii, Muribaculaceae, Lactobacillus amylovorus, and Lactobacillus reuteri) in sows and decreased the relative abundance of Clostridium perfringens type A after feeding B. subtilis administration. These probiotics can repair the intestinal tissue and improve intestinal histomorphology, and enhance the expression of MUC2 and sIgA in sows, thereby further strengthening the mucosal immune function. B. subtilis can also reduce the levels of inflammatory factors (CRP, IL-1β, and IFN-γ) and attenuate the inflammatory response in sows and neonatal piglets. Taken together, our results suggest that dietary supplementation with B. subtilis PB6 could reduce bloat in sows and diarrhea in piglets while improving intestinal barrier function and microbial balance in sows. Full article

Cytotoxic CD8 T lymphocytes are crucial in antiviral immune responses. However, their recruitment to infection sites renders them at risk of viral infection, which could affect their effector activity. CD8 T lymphocytes express RIG-I, which detects cytosolic viral RNA and subsequently induces antiviral gene expression. We investigated how Influenza A virus infection and synthetic triphosphorylated double-stranded RNA, a specific RIG-I ligand, influence TCR-dependent effector responses in primary human CD8 T cells. Cells were isolated from healthy donors and either infected with the reassortant virus RG-PR8-Brazil78 (H1N1) or transfected with the synthetic RNA. Proliferation, degranulation, and cytokine production upon anti-CD3/CD28 stimulation were assessed using flow cytometry and intracellular cytokine staining. Type I IFN production and downstream signaling were measured using IFN-I reporter assay and Western blotting. CRISPR/Cas9 gene editing was employed to knock out RIG-I and STAT2 to evaluate their roles in antiviral responses. Influenza A virus infection of CD8 T cells stimulated RIG-I and activated downstream pathways, including TBK1 and NF-κB, resulting in type-I interferon secretion. Transfection of cytotoxic CD8 T lymphocytes with synthetic RIG-I ligands not only stimulated these pathways but also enhanced the proliferation of CD8 T cells in vitro and protected them from influenza A virus infection. In line with a positive effect on CD8 effector function, both influenza A virus infection and RIG-I ligand transfection enhanced CD8 T cell degranulation and cytokine secretion. Conversely, activation of CD8 T lymphocytes via CD3/CD28 crosslinking increased their susceptibility to influenza A virus infection. We demonstrated that RIG-I stimulation by virus infection or RIG-I ligand transfection promotes intrinsic antiviral pathways and enhances CD8 T-cell effector functions and proliferation. This suggests that RIG-I agonists could enhance and prolong the effector function of cytotoxic CD8 T lymphocytes in immunotherapy. Full article

Viral infections with gastrointestinal involvement remain a significant global health burden with limited therapeutic options. While probiotics show antiviral potential, their impact on primary human intestinal epithelial defenses is poorly defined. This study utilized human intestinal organoid-derived monolayers (ODMs), generated from the non-inflamed mucosa of patients with inflammatory bowel disease, to examine how Bifidobacterium animalis ssp. lactis BB-12 (BB-12) and Lacticaseibacillus rhamnosus GG (LGG) modulate mucosal antiviral pathways. Unlike conventional Caco-2 cells, ODMs preserved physiological cellular diversity and intact innate signaling. Expression of viral receptors and interferon (IFN)-stimulated genes (ISGs) was quantified by RT-qPCR, while the effector 2′-5′-oligoadenylate synthetase 1 (OAS1) was also assessed by immunofluorescence and flow cytometry. Both probiotic strains modulated IFN-associated pathways; however, BB-12 induced a markedly stronger antiviral transcriptional response than LGG. Notably, OAS1 exhibited cell type-specific regulation; while goblet cells showed high basal levels, both probiotics enhanced OAS1 expression selectively in ileal enterocytes. Despite this shared effect, only BB-12 pretreatment significantly restricted Influenza A (H1N1) replication in ileal ODMs, whereas LGG did not significantly affect viral replication. These findings establish human ODMs as a superior platform for probiotic immunology, suggesting that BB-12 more effectively shapes epithelial antiviral “set-points” and highlighting OAS1 as a sensitive component of a broader antiviral program. Full article

Foot-and-mouth disease virus (FMDV) is a highly contagious picornavirus that affects cloven-hoofed animals and carries significant economic implications for the global livestock industry. FMDV features two Leader (L) protein isoforms, Lab and Lb, differing at their amino termini by 28 amino acids (La region). Currently, the activity of La protein sequences has not been investigated. To address this issue, the comparison study of biological and functional roles of Lab and Lb was performed as the La region alone did not independently perform protein function. We found that Lab and Lb significantly regulated FMDV replication and pathogenicity, and their coexistence afforded optimal FMDV properties. Subsequently, we observed that both L isoforms cleaved eukaryotic translation initiation factor 4G (eIF4G) I, suppressed type I and type III interferon (IFN) expression, and exhibited marked cytotoxicity, indicating that they were all key components in FMDV’s antagonism of host antiviral defenses. Finally, the subcellular distribution of Lab and Lb was detected. Despite dual localization in cytoplasmic and nuclear compartments, both isoforms displayed different spatial distribution patterns, and Lb induced more pronounced morphological changes to host cells than Lab. Furthermore, bioinformatics predicted that the La region might contain a non-classical secretory signal peptide, potentially facilitating Lab distribution to the cell membrane or extracellular space. Collectively, the primary encoding role of La region was to control the intracellular distribution of L protein, as opposed to regulating its functional activity. This study may help to deepen our understanding of why FMDV encoded two isoforms of L protein. Full article

Recent evidence suggests that type I interferon (IFN) activity has prognostic relevance in systemic lupus erythematosus (SLE). This study investigated whether combining IFN activity with elevated peripheral blood plasmablast (PB) levels—another key feature of lupus pathophysiology—improves risk stratification for poor clinical outcomes. Clinical data were prospectively collected at a single lupus center. Flow cytometry was performed on freshly isolated peripheral blood mononuclear cells to investigate Sialic acid-binding Immunoglobulin-like Lectin 1 (SIGLEC-1) as a surrogate marker of IFN activity, alongside CD19⁺CD20⁻CD27^highHLA-DR⁺ PB frequencies. A total of 1276 samples from 121 patients were analyzed. At baseline, 48.8% of patients exhibited high IFN activity, including 27.3% with concurrent elevation in IFN and PB activity and 21.5% with isolated IFN activity. Patients with simultaneous IFN and PB activity showed higher anti-dsDNA antibody levels, were less frequently in DORIS remission (24.2% vs. 50.0%) and required higher daily prednisolone dosages (6.3 vs. 2.0 mg) than those with isolated IFN activity. During a median follow-up of 4.5 years (range 0.8–6.6), these patients experienced more flares (132 vs. 54, OR 1.42), required longer to achieve remission (median 399 vs. 140 days), and had a higher median time-adjusted prednisolone dose (5.6 vs. 3.0 mg). Concurrent elevation in IFN and PB activity identifies SLE patients with a poorer prognosis compared to isolated IFN activity. These findings suggest that combined IFN and PB assessment may improve prognostic stratification and support personalized treatment strategies in SLE. Full article