Search Results (304)

Ultraviolet B (UVB) radiation triggers DNA damage and immune suppression, establishing conditions favorable for skin carcinogenesis. Previous studies have shown that a downstream adaptor for Toll-like receptors (TLRs), myeloid differentiation primary response 88 (MyD88), plays a role in UVB-induced DNA damage and immunosuppression. However, specific mechanisms for the effects on dendritic cells and T cells remain poorly understood. The objective of this study is to determine the role of MyD88 and TIR-domain-containing adaptor inducing interferon-β (TRIF), another key TLR downstream adaptor, in UVB-induced suppression of dendritic cell activity and T cell function. MyD88−/−, Trif−/−, and wild-type (WT) mice were evaluated for UVB-induced effects on dendritic cell, T cells, and contact hypersensitivity responses in skin. MyD88−/− mice exhibited significant resistance to UVB-induced immune suppression, compared to Trif−/− mice and wild-type controls. The MyD88 deficiency significantly reduced UVB-induced Treg cells that were CD4⁺CD25⁺Foxp3⁺ and produced interleukin (IL)-10. Moreover, it significantly inhibited the UVB-induced suppression of IL-12/IL-23 producing CD11c⁺ dendritic cells. Further experiments confirmed that MyD88 conditional knockout (MyD88fl/flXCD11c.Cre) mice were protected against UVB-induced immune suppression. Dendritic cells from MyD88 genomic or conditional knockout mice were resistant to UVB-induced reduction of major histocompatibility complex (MHC) class II antigens. These findings show that MyD88 plays a key role in UVB-induced immune suppression. The deficiency in the MyD88 gene inhibits UVB-induced suppression of CD11c+ dendritic cell (DC) activity and reduces UVB-induced development of Treg cells. Our studies demonstrate a new mechanism for MyD88-mediated regulation of UVB-induced immune suppression. Full article

Toxoplasmosis is a relevant parasitic infection in sheep, with ovine meat an important source of human exposure. Accurate detection of the early immune response to Toxoplasma gondii is essential for preventing reproductive losses and improving diagnostic strategies. This study evaluated the kinetics of the acute immune response in eighteen sheep experimentally exposed to live tachyzoites or immunized with parasite-derived glycoconjugates (GlyC). Animals were divided into three groups and injected with saline solution, tachyzoites, or glycoconjugates combined with an adjuvant. Infected sheep developed specific IgM antibodies against both lysate and glycoconjugate antigens from day 4, and IgG against glycoconjugates from day 12 post-infection. Glycoconjugate-immunized sheep produced IgM against lysate antigens from day 4, and IgG against both antigens from day 12. Flow cytometry revealed a significant increase in circulating CD8+ T cells and a reduction in MHC class II+ cells on day 60 in the infected group. These findings demonstrate the early humoral and cellular immune response profiles following infection or GlyC immunization. This supports their future application in diagnostic tests or as vaccine candidates against toxoplasmosis in sheep. Full article

Background and Objectives: The pathogenesis of thyroid eye disease (TED) is driven by interactions between orbital fibroblasts and immune cells. Lymphocyte-activation gene 3 (LAG-3) is an immune checkpoint molecule with a similar structure to the T lymphocyte CD4 receptor but with higher affinity for MHC class II, and LAG-3–MHC class II interaction inhibits T lymphocyte activity. Lymphocytes shed LAG-3, generating soluble LAG-3 (sLAG-3), whose function is unclear. We investigated sLAG-3 involvement in Graves’ disease (GD) and GD-associated TED pathogenesis. Materials and Methods: Patients with GD-associated TED (n = 47) and GD without TED (n = 35) were enrolled alongside 37 healthy controls (HCs). Peripheral blood serum sLAG-3 levels were measured using enzyme-linked immunosorbent assays and compared across the three groups. The effect of intravenous glucocorticosteroid (IVGC) treatment (12 weeks) on sLAG-3 concentrations in patients with GD-associated TED was monitored, and associations of sLAG-3 levels with clinical characteristics were analyzed. Disease activity before and after IVGC treatment was assessed using Clinical Activity Score. Results: Relative to those in HCs, serum sLAG-3 levels were significantly higher in GD patients both with (p < 0.001) and without (p = 0.0129) TED. No significant difference in sLAG-3 levels was observed between the two patient groups (p = 1.000), and no significant change in sLAG-3 levels was detected in patients with TED after IVGC therapy (p = 0.0536). Conclusions: The higher sLAG-3 levels in patients compared to HCs suggest that sLAG-3 dysregulation may contribute to GD and GD with orbitopathy development and the pathomechanisms underlying these conditions. Metalloproteinase-mediated cleavage of LAG-3 from the lymphocyte surface enables T lymphocyte proliferation and activation, while released sLAG-3 may enhance the immune response. Further studies of sLAG-3’s mechanisms of action are needed to establish clear cut-off values and to define the diagnostic role of sLAG-3 in GD diagnosis. Full article

Mouse bone marrow-derived dendritic cells (BMDCs) were infected in vitro with the recombinant Brucella melitensis M5^+gfp strain. The immunopeptidome of Brucella melitensis M5^+gfp, which presented peptides bound to MHC class II molecules on their surface, was isolated and characterized. BMDCs infected with Brucella melitensis M5^+gfp were subjected to hypotonic lysis. The associated immunopeptidome was then isolated and characterized using co-immunoprecipitation (Co-IP) coupled with liquid chromatography–tandem mass spectrometry (LC-MS/MS). A total of 289 MHC-II-bound Brucella melitensis M5^+gfp peptide sequences were identified, mapping to 183 distinct proteins. We successfully define the Brucella melitensis M5^+gfp immunopeptidome presented by MHC-II on infected BMDCs. The source proteins of these peptides exhibited significant abundance and functional, structural, and pathway diversity. This study demonstrates that during antigen presentation by antigen-presenting cells (APCs), Brucella melitensis peptides presented by MHC-II originate from a broad repertoire of proteins, not limited to surface antigens. This complex immunopeptidome, shaped by active selection mechanisms, provides diverse targets for host immune recognition. These findings establish a foundation for further investigation into the transfer of comprehensive immune information between immune cells and the elicitation of immune responses. This work also paves the way for identifying specific T-cell receptors involved in recognition and immune activation, thereby facilitating the analysis of adaptive immunity’s molecular basis. Furthermore, this study provides an innovative approach for immunopeptidome analysis, providing a crucial theoretical foundation for developing novel Brucella melitensis subunit vaccines. Full article

Ectopic expression of human leukocyte antigen class II (HLA-II) on tumor cells correlates with anti-tumor immunity and prognosis in various cancers, but its role in esophageal squamous cell carcinoma (ESCC) remains unclear. Methods: HLA-II expression was evaluated in 34 ESCC tissue sections and a 102-sample tissue microarray (TMA) using immunohistochemistry (IHC) and in 10 ESCC cell lines via flow cytometry. Transcriptome sequencing of KYSE270, KYSE180, KYSE450, and KYSE510 was performed to investigate HLA-II regulatory mechanisms, while tumor samples from 104 ESCC patients were analyzed for neoantigen load. The prognostic significance of neoantigen burden was assessed using Cox regression. Results: HLA-II was ectopically expressed in ESCC, with positivity rates of 20.59% (34 tissues) and 25.49% (TMA). Among 10 ESCC cell lines, only KYSE270 exhibited spontaneous HLA-II expression. Transcriptome analysis revealed 1278 KYSE270-specific genes enriched in immune-related pathways (e.g., “Cytokine–cytokine receptor interaction”), suggesting immune-mediated HLA-II regulation. IFN-γ stimulation induced HLA-II expression in KYSE180, KYSE450, and KYSE510, indicating broader inducible HLA-II potential. In 104 patients, MHC-II-restricted neoantigen burden varied widely (0–75) and lacked direct correlation with HLA-II expression. Additionally, MHC-II-restricted neoantigen load was not significantly associated with overall survival (p > 0.05). Conclusion: Ectopic HLA-II expression in ESCC may influence the tumor immune microenvironment, while the prognostic value of MHC-II-restricted neoantigen burden in ESCC remains unclear, providing potential implications for immunotherapy strategies. Full article

Introduction: Bovine leukemia virus is a single-stranded RNA virus that targets B cell CD5⁺ lymphocytes in cattle. Only a tiny percentage of individuals develop malignant lymphoproliferative disorders, while most remain healthy carriers or experience persistent lymphocytosis. The exact mechanisms leading to lymphoma development are complex and not fully understood. RNA-seq analysis of cows’ peripheral blood leukocytes (PBLs) with and without Bovine leukemia virus (BLV) antibodies was conducted to gain a deeper understanding of molecular events beyond BLV infection. Method: Eighteen samples were selected, and their RNA was sequenced. For gene expression analysis and protein–protein network interactions, three groups were selected, including healthy negative samples (CT, n = 7), asymptomatic carriers (AC, n = 5), and persistent lymphocytosis (PL, n = 6), to provide the differentially expressed gene (DEG) and protein–protein interaction network (PPIN) outputs. Results: Our results demonstrated that in comparison to CT, ACs upregulated TLR7 and transcription activation factors. In the CT vs. PL group, MHC class II, transcription activation factors, and anti-inflammatory cytokines increased, while the acute-phase proteins, antiviral receptors, and inflammatory cytokines decreased. Additionally, antiviral receptors, acute-phase proteins, and inflammatory receptors were downregulated in the PL versus the AC groups. Moreover, PPINs analysis suggested that nuclear receptor corepressor 1 (NCOR1), serine/arginine repetitive matrix 2 (SRRM2), LUC7 like 3 pre-mRNA splicing factor (LUC7L3), TWIST neighbor (TWISTNB), U6 small nuclear RNA and mRNA degradation associated (LSM4), eukaryotic translation elongation factor 2 (EEF2), ubiquitin C (UBC), CD74, and heterogeneous nuclear ribonucleoprotein A2/B1 (HNRNP A2B1) are possible hub gene candidates in the PL group. Conclusions: Our results suggest that innate and cellular immune responses are more loose in severe BLV infectious conditions, while the PPINs revealed that new protein interactions are necessary for oncogenesis. Full article

Background: Ovarian cancer is an immunologically cold tumor that is treated with surgery and a chemotherapy regimen of platinum agents with taxanes. Paradoxically, elevated levels of several immune markers are effective at predicting prognosis for patients with ovarian cancer, though it is not clear how chemotherapy might influence this. Chemotherapy elicits immunogenic cell death, yet tumor-controlling doses of chemotherapy are also immunotoxic. Objectives: To evaluate interactions of chemotherapy with the immune system, we studied the impact of chemotherapy in an aggressive mouse model of ovarian cancer developed within our lab. Methods: Using a single-cell transcriptomics sequencing approach, supported by flow cytometry, we evaluated the influence of a first-line therapy, cisplatin and docetaxel, and a second-line therapy, pegylated liposomal doxorubicin (PLD), on control of tumor growth and on tumor-associated immune populations of cells. Results: Both chemotherapy approaches were effective at controlling tumor growth and selectively depleted tumor cells from distinct transcriptional clusters. Both chemotherapies also resulted in relative increases in immune populations compared to untreated tumor-bearing mice, but immune populations from PLD-treated mice were more abundant and expressed a greater fraction of maturity-associated transcripts and increased proportions of tumor resident macrophage populations. PLD treatment selectively upregulated MHC class II on tumor cells, and this could be replicated in vitro across ovarian cancer cell lines and in patient tumor cells ex vivo. Conclusions: Altogether, the results support the notion that PLD has a greater capacity for immunopotentiation, which may be important to consider if immunotherapy approaches are adapted for ovarian tumors in the future. Full article

Background: This study aimed to investigate the impact of the diabetic environment on the development of experimental autoimmune uveoretinitis (EAU) and the activation status of microglia in the eye. Methods: EAU was induced in wild-type (WT) and streptozotocin (STZ)-induced diabetic mice (STZ-EAU mice). Disease severity was assessed using funduscopy, optical coherence tomography (OCT), and histopathological analysis. The proportions of Th1, Th17, and regulatory T cells in the spleen were analyzed by flow cytometry. Retinal microglia were quantified using immunohistochemistry. To further characterize retinal cell populations and gene expression profiles, single-cell RNA sequencing (scRNA-seq) was performed. Results: STZ-EAU mice exhibited significant reductions in both the incidence and severity of EAU compared with WT-EAU mice. These were accompanied by a decreased proportion of Th1 cells, which are crucial for EAU pathogenesis, in the spleens of STZ-EAU mice. Retinal microglial accumulation was markedly reduced in STZ-EAU mice compared with WT-EAU mice. scRNA-seq analysis revealed a significant change in the microglial phenotype in STZ-EAU mice, characterized by decreased expression of MHC class I/II and the suppression of antigen presentation signaling pathways. Activated microglia in STZ-EAU mice showed reduced gene expression of M1 markers (CD68, CD74, and IL1B) and increased gene expression of M2 markers (MSR1, CD163, and MRC1), suggesting a shift toward an anti-inflammatory M2 phenotype. Conclusions: EAU is suppressed in STZ-induced diabetic mice, likely due to alterations in microglial polarization toward an M2 phenotype. These results suggest a decrease in T cell responses to pathogens in a diabetic environment, which could be one of the underlying factors for the increased susceptibility to infection in diabetic patients. Inhibiting the M2 polarization of microglia may reduce the susceptibility to infection in patients with diabetes. Full article

The presently used vaccines do not offer solid immunity/protection against the currently circulating strains of the H5N1 viruses. We aim to design a pan-H5N1 vaccine that protects birds against the presently circulating clade 2.3.4.4b in chickens. We used AI tools, including epitope mapping, molecular docking, and immune simulation, to design a multiepitope DNA vaccine including the top-ranked B and T cell epitopes within four major proteins (HA, NA, NP, and M2) of H5N1 clade 2.3.4.4b. We selected the top-ranked 12 epitopes and linked them together using linkers. The designed vaccine is linked to IL-18 as an adjuvant. The molecular docking results showed a high binding affinity of those predicted epitopes from the MHC I and MHC II classes of molecules with chicken alleles. The immune simulation results showed that the designed vaccine has the potential to stimulate the host immune response, including antibody and cell-mediated immunity in chickens and other birds. We believe this vaccine is going to be a universal vaccine that offers good protection against HPAI-H5N1 clade 2.3.4.4b. We are reporting the successful molecular cloning of a recombinant multiepitope-based vaccine spanning some key epitopes within some key proteins of the currently circulating H5N1 clade 2.3.4.4b. These designed vaccines could be a great positive impact on the protection of birds and various species of animals, as well as humans, against the HP-H5N1 influenza virus. Further studies are required to validate this vaccine candidate in chickens. Full article

The endangered Bengal slow loris (Nycticebus bengalensis) relies heavily on captive/rescue populations for conservation. This study investigated the critical link between Major Histocompatibility Complex (MHC) class II DRB1 exon 2 (DRB1e2) genetic variation and gut microbiota in 46 captive individuals, aiming to improve ex situ management. Using standardized conditions across three enclosure types, we characterized DRB1e2 polymorphism via targeted sequencing and analyzed fecal microbiota using 16S rRNA gene amplicon sequencing. Results demonstrated that high DRB1e2 polymorphism significantly reduced microbial community evenness. Specific genotypes showed distinct microbial associations: G9 strongly correlated with beneficial short-chain fatty acid producers like Fructobacillus, and G2 positively correlated with Bifidobacterium spp., while G2, G3, and G4 correlated negatively with Buchnera (a nutrient-provisioning symbiont). Genotypes and polymorphism collectively explained 9.77% of microbiota variation, exceeding the weaker (5.15%), though significant, influence of enclosure type on β-diversity. These findings reveal that host DRB1e2 variation is a primary driver shaping gut microbiota structure and taxon abundance in captive slow lorises, providing evidence for MHC-mediated host–microbe co-adaptation. This offers a genetically informed framework for optimizing conservation strategies, such as tailoring diets or probiotics to specific genotypes, to enhance gut health and population viability. Full article

Oncolytic herpes simplex virus (oHSV) is a promising cancer immunotherapy that induces tumor cell lysis and stimulates anti-tumor immunity. Our previous single-cell RNA sequencing analysis of oHSV-treated medulloblastoma tumors revealed expansion and activation of tumor-infiltrating dendritic cells (DCs), and direct oHSV infection of DCs within the brain. While the therapeutic effects of oHSVs have been primarily attributed to tumor cell infection, we hypothesize that direct infection of DCs also contributes to therapeutic efficacy by promoting DC maturation and immune activation. Although the oHSV infection in DCs was abortive, it led to increased expression of major histocompatibility complex (MHC) class I/II and co-stimulatory molecules. oHSV-infected DCs activated naïve CD4⁺ and CD8⁺ T cells, inducing expression of CD69 and CD25. These primed T cells exhibited enhanced cytotoxicity against CT-2A glioma cells. Adoptive transfer of oHSV-infected DCs via subcutaneous injection near inguinal lymph nodes delayed tumor growth in a syngeneic CT-2A glioma model, independent of tumor viral replication and lysis. Mechanistically, our in vitro studies demonstrate that oHSV can directly infect and functionally activate DCs, enabling them to prime effective anti-tumor T cell responses. This study highlights the anti-tumor potential of leveraging oHSV-infected DCs to augment viroimmunotherapy as a cancer therapeutic. Full article

T lymphocytes in human skin play essential roles in immune surveillance and tissue homeostasis, with distinct populations residing in the epidermal and dermal compartments. To characterize the molecular basis of their compartmentalized functional specialization, we performed proteomic analysis of total T cell populations isolated from healthy human skin, combining flow cytometry and liquid chromatography–tandem mass spectrometry. We quantified 5985 proteins across epidermal and dermal T cell populations, identifying 2177 significantly differentially expressed proteins (FDR < 0.05), including 1008 with >2-fold changes. Compared with dermal T cells, epidermal T cells showed elevated intensity of tissueresidency marker CD69, co-stimulatory protein CD27, complement components (C3, C4a, and Factors B and D), and proteins involved in oxidative phosphorylation and cholesterol metabolism. Epidermal T cells also exhibited higher levels of antimicrobial S100 proteins, chemokine receptor CCR6, IL-18, and MHC class I molecules, while, in contrast, dermal T cells showed increased expression of CXCR4, IL-16, and MHC class II-related proteins. While these distinct proteomic signatures suggest compartment-specific adaptations in metabolism, immune surveillance, and antigen presentation, the results should be interpreted as exploratory, given methodological limitations. Nonetheless, this study provides a valuable molecular resource for understanding the specialization of T cells within different skin layers and offers a basis for future investigations into skin immune biology and its potential implications in disease. Full article

Background: Anti-programmed death 1 receptor (PD-1) therapy is a promising treatment strategy for patients with unresectable advanced or recurrent gastric/gastroesophageal junction (G/GEJ) cancer. However, its response rate and survival benefits are still limited; an immunological analysis of the residual tumor after anti-PD-1 therapy would be important. Methods: We evaluated the clinical efficacy of tumor resection (TR) after chemotherapy or anti-PD-1 therapy in patients with unresectable advanced or recurrent G/GEJ cancer and analyzed the immune status of tumor microenvironment (TME) by immunohistochemistry using their surgically resected specimens. Results: Patients treated with TR after anti-PD-1 therapy had significantly longer survival compared to those treated with chemotherapy and anti-PD-1 therapy alone. Expression of human leukocyte antigen (HLA) class I and major histocompatibility complex (MHC) class II on tumor cells was markedly downregulated after anti-PD-1 therapy compared to chemotherapy. Furthermore, the downregulation of HLA class I may be associated with the activation of transforming growth factor-β signaling pathway in the TME. Conclusions: Immune escape from cytotoxic T lymphocytes may be induced in the TME in patients with unresectable advanced or recurrent G/GEJ cancer after anti-PD-1 therapy due to the downregulation of HLA class I and MHC class II expression on tumor cells. TR may be a promising treatment strategy for these patients when TR is feasible after anti-PD-1 therapy. Full article

Recent preclinical and clinical studies have confirmed the essential role of interferons in the host’s immune response against malignant cells. Merkel cell carcinoma (MCC) is a rare, aggressive skin cancer strongly associated with Merkel cell polyomavirus (MCPyV). Despite progress in understanding MCC pathogenesis, the role of innate immune signaling, particularly interferon-γ (IFN γ) and its downstream pathways, remains underexplored. This review summarizes recent findings on IFN-γ in MCC, highlighting its dual role in promoting both antitumor immunity and immune evasion. IFN-γ enhances cytotoxic T cell responses, upregulates MHC class I/II expression, and induces tumor cell apoptosis. Transcriptomic studies have shown that IFN-γ treatment upregulates immune-regulatory genes including PD-L1, HLA-A/B/C, and IDO1 by over threefold; it also activates APOBEC3B and 3G, contributing to antiviral defense and tumor editing. Clinically, immune checkpoint inhibitors (ICIs) such as pembrolizumab and avelumab yield objective response rates of 30–56% and two-year overall survival rates exceeding 60% in advanced MCC. However, approximately 50% of patients do not respond, in part due to IFN-γ signaling deficiencies. This review further discusses IFN-γ’s crosstalk with the STAT1/3/5 pathways and emerging combination strategies aimed at restoring immune sensitivity. Understanding these mechanisms may inform personalized immunotherapeutic approaches and guide the development of IFN-γ–based interventions in MCC. Full article

Amyotrophic lateral sclerosis (ALS) is characterized by upper and lower motor neuron failure and poor prognosis. This study performed a meta-analysis of gene expression datasets that compared bulk-processed post-mortem spinal cord from ALS and control (CTL) patients. The analysis included 569 samples (454 ALS, 115 CTL) from 348 individuals (262 ALS, 86 CTL). Patterns of differential expression bias, related to mRNA abundance, gene length and GC content, were discernable from individual studies but attenuated by meta-analysis. A total of 213 differentially expressed genes (DEGs) were identified (144 ALS-increased, 69 ALS-decreased). ALS-increased DEGs were most highly expressed by microglia and associated with MHC class II, immune response and leukocyte activation. ALS-decreased DEGs were abundantly expressed by mature oligodendrocytes (e.g., the MOL5 phenotype) and associated with myelin production, plasma membrane and sterol metabolism. Comparison to spatial transcriptomics data showed that DEGs were prominently expressed in white matter, with increased DEG expression strongest in the ventral/lateral white matter. These results highlight white matter as the spinal cord region most strongly associated with the shifts in mRNA abundance observed in bulk-processed tissues. These shifts can be explained by attrition of mature oligodendrocytes and an ALS-emergent microglia phenotype that is partly shared among neurodegenerative conditions. Full article