Search Results (77)

Background: Depression and Metabolic Dysfunction-Associated Steatotic Fatty Liver Disease (MASLD) are common chronic diseases, respectively. However, the causal and molecular links between them remain unclear. In order to explore whether depression contributes to an increased risk of MASLD and whether inflammation mediates this effect, we integrated multi-level evidence from the epidemiology of the National Health and Nutrition Examination Survey (NHANES), the genetics of GWAS, the transcriptomes of GEO, and single-cell RNA sequencing datasets. Methods: A multi-level integrative analysis strategy was used to validate this pathway. First, a cross-sectional epidemiological analysis based on NHANES data was used to reveal the association between depression and MASLD, and to explore the mediating role of inflammation and liver injury markers. Secondly, a two-sample Mendelian randomization analysis was used to infer the causal direction of depression and MASLD, and to verify the mediating effect of systemic inflammation and liver injury indicators at the genetic level. Then, the transcriptome co-expression network analysis and machine learning were used to screen the common hub genes connecting the two diseases. Finally, single-cell transcriptome data were used to characterize the dynamic expression of potential key genes during disease progression at cellular resolution. Results: Depression significantly increased the risk of MASLD, especially in women (OR = 1.39, 95%CI [1.17–1.65]). Parallel mediation analysis showed that high-sensitivity C-reactive protein (hs-CRP) (p < 0.001), γ-glutamyltransferase (GGT) (p < 0.001), and alkaline phosphatase (ALP) (p < 0.001) mediated this relationship. Mendelian randomization analysis confirmed the unidirectional causal effect of depression on MASLD, and there was no reverse association (β = 0.483, SE = 0.146, p = 0.001). Weighted gene co-expression network analysis and machine learning identified CD40LG as a potential molecular bridge between depression-associated immune modules and MASLD. In addition, single-cell data analysis revealed a stage-specific trend of CD40LG expression in CD4⁺ T cells during MASLD progression, while its receptor CD40 was also activated in B cells. In the female sample, CD40LG maintained an upward trend. However, the stability of this result is limited by the limited sample size. Conclusions: This study provides converging multi-omics evidence that depression plays a causal role in MASLD through inflammation-mediated immune signaling. The CD40LG-CD40 axis has emerged as an immune mechanism that transposes depression into the pathogenesis of MASLD, providing a potential target for the intervention of gender-specific metabolic liver disease. Full article

B-cells and plasmablasts have emerged as central organizers of autoimmune pathogenesis, extending far beyond their classical role as antibody-producing cells to orchestrate immune circuits, tissue microenvironments, and therapeutic trajectories. Advances in single-cell technologies, high-dimensional cytometry, and B-cell receptor sequencing have uncovered a dynamic continuum of B-cell differentiation programs that drive clinical heterogeneity across systemic autoimmune diseases. Plasmablasts, in particular, have gained recognition as highly responsive sensors of immune activation: they expand during flares, encode interferon-driven and extrafollicular responses, and correlate with disease severity. Autoantibody profiles, long viewed as static diagnostic signatures, are now understood as durable molecular footprints of distinct B-cell pathways. In this review, we propose an endotype-based framework integrating B-cell circuits with clinical phenotypes, illustrate therapeutic decision-making through mechanistic case vignettes, and outline future strategies combining immunomonitoring, multi-omics, and precision therapeutics. We further address translational challenges and discuss complementary approaches, including T-cell modulation, FcRn inhibition, and antigen-specific tolerization. Full article

Diabetic kidney disease (DKD) is a leading cause of end-stage renal disease worldwide. However, the inflammatory mediators that causally drive disease progression remain incompletely defined. In this study, we used a multi-omics approach that combined single-cell RNA sequencing, spatial transcriptomics, pseudotime trajectory analysis, cell-to-cell communication analysis, and Mendelian randomization (MR) to investigate the role of tumor necrosis factor receptor superfamily member 1A (TNFRSF1A) in DKD development. Findings were further validated in zebrafish embryos depleted of pdx1, an established model of DKD. Spatial transcriptomic analysis showed that TNFRSF1A is enriched in cortical kidney regions. Pseudotime analysis revealed progressive immune reprogramming, with an early predominance of T and NK cells and gradual shift to myeloid infiltration and B-cell expansion. Cell-to-cell communication analysis highlighted IL-1β and related signaling pathways that increase NF-κB activity. Mendelian Randomization analysis, complemented by PPI network mapping, identified TNFRSF1A (OR = 1.78, 95% CI: 1.17–2.71, p = 0.007) as a gene with genetic evidence supporting a causal association. Consistent with the human data, experiments in zebrafish showed that TNFRSF1A expression increases significantly following pdx1 knockdown (p = 0.0025). Together, these findings support a role for TNFRSF1A in immune microenvironment reprogramming in DKD, while not excluding the involvement of additional regulatory pathways. Full article

Nile tilapia (Oreochromis niloticus) is a globally important aquaculture species. However, intensive farming conditions increase the risk of bacterial diseases. Despite the fact that a considerable number of transcriptomic studies have examined host responses to single bacterial infections, comparative analyses conducted within a unified experimental framework remain scarce, limiting the understanding of pathogen-specific defence mechanisms. In this study, tilapia were experimentally infected with Streptococcus agalactiae, Escherichia coli, or Vibrio harveyi via thoracic injection. Head kidney tissues were collected at 48 h post-infection for RNA sequencing. The identification of differentially expressed genes (DEGs) was conducted utilising the edgeR, and the assessment of functional enrichment was facilitated through the implementation of Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. A comparative analysis was conducted between the bacterial infection groups and the control group. The results of this analysis revealed the identification of 2930, 3328, and 4850 DEGs were identified in the S. agalactiae, E. coli, and V. harveyi infection groups, respectively. Integrated transcriptomic analysis, combining KEGG enrichment and expression profiling of key genes, revealed distinct response patterns across pathogens. The S. agalactiae infection predominantly activated innate immune signaling pathways, including Toll-like receptor, NOD-like receptor, cytokine–cytokine receptor interaction, and NF-κB pathways. In contrast, E. coli infection induced extensive metabolic reprogramming, notably in purine and pyrimidine metabolism, carbon metabolism, and amino acid biosynthesis. Meanwhile, an infection caused by V. harveyi resulted in mucosal and lysosomal defence responses, as evidenced by an increase in lysosome, phagosome, extracellular matrix–receptor interaction, and cell adhesion molecule pathways. Collectively, this study suggests that the head kidney of Nile tilapia employs pathogen-specific defence strategies rather than a uniform antibacterial response, providing one of the first transcriptomic comparisons of distinct bacterial infections in this species. These findings provide fundamental data and theoretical insights for elucidating immune mechanisms in teleost fish and for developing targeted prevention and control strategies in aquaculture. Full article

Chimeric antigen receptor (CAR) T cell therapy for B cell malignancies is often limited by T cell exhaustion, which is frequently driven by the PD-1/PD-L1 immune checkpoint axis. To overcome this, we developed an “armored” CAR-T cell strategy using a novel bidirectional promoter system. We engineered a single vector to co-express a CD19-specific CAR alongside a secreted anti-PD1 molecule, in either a full-length antibody or a single-chain variable fragment (scFv) format, using the Sleeping Beauty (SB) transposon system. The sequences for the anti-PD1 modules were derived from the clinical antibody nivolumab. Both armored constructs demonstrated robust CAR expression, comparable to or higher than conventional CAR-T cells, and proliferated significantly more than untransfected controls. The engineered cells successfully secreted their anti-PD1 payloads, with the full-length antibody showing more sustained secretion than the scFv. This autocrine blockade resulted in significantly reduced surface PD1 expression on the armored CAR-T cells. Functionally, the anti-PD1-secreting cells exhibited superior cytotoxicity against PD-L1-positive Raji target cells, particularly at low effector-to-target ratios. Critically, in a serial rechallenge assay designed to simulate chronic antigen exposure, both armored CAR-T cell groups showed markedly enhanced proliferation and persistence compared to conventional CAR-T cells, which failed to expand after repeated stimulation. Our findings validate the bidirectional EF1 promoter as an efficient system for generating multi-functional T cells and demonstrate that armoring CAR-T cells with secreted anti-PD1 antibodies is a potent strategy to enhance their persistence and anti-tumor efficacy. Full article

Polycystic ovary syndrome (PCOS) is a complex endocrine disorder affecting reproductive-aged women. Previous studies have identified genomic associations at chromosome 12q13.2, but the functional mechanisms underlying these associations remain unclear. We integrated three complementary datasets: (1) WES-identified single nucleotide variants (SNVs) from PCOS and normal theca cells with association testing for forskolin-stimulated androgen production, (2) STARR-seq enhancer activity data with eQTL colocalization analysis, and (3) scRNA-seq expression data comparing forskolin-stimulated PCOS and normal theca cells. We previously identified haplotypes involving 10 SNVs at 12q13.2 containing RPS26/RAB5B/SUOX that are significantly associated with forskolin-stimulated androgen production. The identified haplotypes were further shown to associate with PCOS in a whole genome sequencing (WGS) cohort. Other studies have recently found the enhancer variant rs1081975 demonstrated perfect colocalization (PP = 1.0) with RPS26/RAB5B/SUOX eQTLs. Our scRNA-seq analysis revealed differential expression patterns for key genes. RAB5B showed a forskolin response upregulation in normal cells but an impaired response in PCOS. SUOX exhibited opposite forskolin responses between normal and PCOS cells. PA2G4, an androgen corepressor in the locus, was upregulated in normal untreated cells. ERBB3, an epidermal growth factor receptor in the locus, was downregulated in normal forskolin treated cells. The integration of multimodal genomic data provides functional validation of PCOS-associated variants at 12q13.2, revealing coordinated dysregulation of vesicular trafficking (RAB5B), androgen receptor regulation (PA2G4), and metabolic processes (SUOX) in PCOS theca cells. Full article

Background: The minimized pan-coronavirus (CoV) vaccine-1 developed by our laboratory contained pDNA sequences of feline coronavirus serotype-1 (FCoV1) and SARS-CoV2 (SCoV2) spike B-cell epitopes plus FCoV/SCoV2-conserved, CoV-specific polymerase cytotoxic T-lymphocyte (CTL) epitopes formulated in lipid nanoparticle (LNP). Only FCoV2 infects feline cell lines needed for developing native challenge inoculum that causes feline infectious peritonitis (FIP). Hence, Pilot Study 1 evaluated the therapeutic efficacy and safety of the pan-CoV vaccine-1 in feline immunodeficiency virus (FIV)-infected cats, with or without FCoV1 coinfection. Pilot Study 2 evaluated the cross-protective effect of pan-CoV vaccines in specific-pathogen-free (SPF) cats against intranasal challenge with FIP virus serotype 2 (FIPV2). Methods: In Study 1, we vaccinated two FIV-infected cats (one negative and another positive for FCoV1 coinfection) intramuscularly twice with CTL epitopes-LNP vaccine and later twice with pan-CoV vaccine-1. Controls included two unvaccinated FIV-infected cats with or without FCoV1 coinfection. Study 2 assessed the sequential vaccinations of three pan-CoV vaccines in four SPF cats. The first two vaccinations were with pan-CoV vaccine-2, followed by pan-CoV vaccine-3 (twice), and lastly with pan-CoV vaccine-1 (once). Three SPF controls included two cats immunized with LNP and one lacking any immunization. Pan-CoV vaccine-2 contained pDNAs with modified FCoV1/SCoV2 B-cell epitopes plus CTL epitopes in LNP. Pan-CoV vaccine-3 contained only pDNAs with FCoV1 B-cell epitopes plus CTL epitopes in LNP. Results: Study 1 demonstrated no adverse effect with 25 μg and 50 μg CTL epitopes-LNP vaccine and 50 μg pan-CoV vaccine-1. However, 100 μg pan-CoV vaccine-1 caused fever 24 h later, which was resolved by a single Meloxicam treatment. Both vaccinees developed cross-FCoV2 neutralizing antibodies (XNAbs), immunoblot binding antibodies (bAbs) to FCoV1 receptor-binding domain (RBD), and T-cell responses to FCoV1 RBD, whereas one vaccinee also developed bAbs to SCoV2 RBD. Study 2 demonstrated no adverse effects after each vaccination. Three vaccinees developed low-titer XNAbs and bAbs to FCoV2 spike-2 by the fourth vaccination. Upon challenge, all cats developed FCoV2 NAbs and bAbs to FCoV2 nucleocapsid and RBD. High vaccine-induced T-cell responses to FCoV1 RBD and T-cell mitogen responses declined with an increase in responses to FCoV2 RBD at three weeks post-challenge. Two of the three controls died from FIP, whereas one vaccinee, with the lowest vaccine-induced immunity, died from skin vasculitis lesions and detection of FIPV2 infection by semi-nested RT-snPCR in feces. Conclusions: In Pilot Study 1, the pan-CoV vaccine-LNP dose of 50 μg had no adverse effects, but adverse effects were observed at 100 μg dose. In Pilot Study 2, the FCoV1-based B-cell vaccine(s) induced low levels of XNAbs against FIPV2 and delayed challenge infection against high-dose FIPV2. The high-dose FIPV2 infections in the vaccinated and control cats started to clear, by single housing at 23–26 weeks post-challenge, whereas two cats in Pilot Study 1 cleared natural FCoV1 transmission by 26 weeks post-infection. Full article

Acute lymphoblastic leukemia (ALL) remains a formidable therapeutic challenge, particularly within high-risk cohorts. Advances in next-generation sequencing have elucidated critical mutations that significantly influence prognosis and therapeutic decision-making. Tyrosine kinase inhibitors (TKIs) have significantly improved treatment outcomes in Philadelphia chromosome-positive (Ph+) ALL. Meanwhile, emerging therapies such as monoclonal antibodies and chimeric antigen receptor (CAR) T-cell therapies show promise for B-cell ALL, although they are associated with considerable toxicities. These developments underscore the persistent need for alternative therapeutic strategies that can benefit a wider range of patients. In this study, human ALL cell lines—characterized by either wild-type or mutant tumor protein p53 (TP53) status—were treated with RG7388 (an MDM2 (mouse double minute 2 homolog) inhibitor) and BBI608 (a STAT3 (signal transducer and activator of transcription 3) inhibitor), both as single agents and in combination. Cell viability was quantified using XTT assays, while apoptosis was assessed via flow cytometry. Additionally, immunoblotting and qRT-PCR were employed to evaluate changes in protein and gene expression, respectively. RG7388 demonstrated potent growth inhibition in the majority of ALL cell lines, with p53-mutant cell lines exhibiting resistance. BBI608 reduced cell viability across all tested cell lines, though with variable sensitivity. Notably, the combination of RG7388 and BBI608 elicited synergistic anti-proliferative effects in p53 wild-type and partially functional p53-mutant cells, enhancing apoptosis and stabilizing p53 protein levels. In contrast, MOLT-4 cells, which harbor concurrent TP53 and STAT3 mutations, did not benefit from the combination treatment, indicating an inherent resistance phenotype within this subset. Collectively, these findings highlight the therapeutic potential of combined MDM2 and STAT3 inhibition in ALL, particularly in p53 wild-type and partially functional p53-mutant contexts. This combinatorial approach augments apoptosis and tumor growth suppression, offering a promising avenue for expanding treatment options for a broader patient population. Further investigation is warranted to validate these preclinical findings and to explore translational implications in genetically diverse ALL subsets. 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

Eilat (EILV)/chikungunya virus (CHIKV) is a chimeric virus that contains the nonstructural proteins and cis-acting sequences of EILV and the structural proteins of CHIKV. EILV/CHIKV vaccination is known to protect with a single dose against wild-type (WT) CHIKV challenge in mice and non-human primates. The underlying immune mechanism of the vaccine-induced host protection remains unknown. γδ T cells react to WT CHIKV infection by controlling the virus-induced tissue inflammation and damage. Here, we found that γδ T cells contribute to EILV/CHIKV-induced host protection against WT CHIKV infection. TCRδ^−/− mice, which are deficient of γδ T cells, had impaired CHIKV-specific CD8⁺ T cell responses, antibody production and memory B cell responses following vaccination. Both antibody and CD8⁺ T cells of EILV/CHIKV-vaccinated mice were required for protection type I interferon receptor deficient mice from lethal WT CHIKV infection. Moreover, γδ T cells expanded quickly in response to EILV/CHIKV vaccination. TCRδ^−/− mice, had lower levels of innate immune cytokines and impaired activation of antigen presenting cell (APCs). Overall, γδ T cells contribute to EILV/CHIKV-induced host protection by promoting APC maturation, T cell priming and the induction of humoral immune responses upon EILV/CHIKV vaccination. Full article

Background: Irradiation (IR) targets cancer cells, but also the tumor microenvironment, including the tumor’s blood vessels. In addition to tumor endothelial cell (TEC) apoptosis, IR can lead to TEC activation, potentially increasing immune cell infiltration. However, the changes underlying the IR-induced activation of endothelial cells (ECs) are poorly understood. This study investigated dose- and time-dependent molecular and functional responses of murine and human EC lines to IR in vitro and TECs in vivo in murine tumor models of colorectal carcinoma. Methods: HUVEC, EA.hy926, and Hulec5a, as well as murine bEND.3, 2H11, and SVEC4-10 EC lines, were irradiated with single doses of 2–10 Gy. EC proliferation and survival after IR were assessed by staining all nuclei (Hoechst 33342) and dead cells (propidium iodide) every 24 h for 5 days using the Cytation 1 Cell Imaging Multi-Mode Reader. RNA sequencing analysis of HUVECs irradiated with 2 Gy and 5 Gy at 24 h and 72 h after IR was conducted, focusing on processes related to EC activation. To validate the RNA sequencing results, immunofluorescence staining for proteins related to EC activation, including Stimulator of Interferon Response cGAMP Interactor 1 (STING), Nuclear factor kappa B (NF-κβ), and Vascular cell adhesion molecule 1 (VCAM-1), was performed. To validate the in vitro results, the response of TEC in vivo was analyzed using publicly available RNA sequencing data of TECs isolated from MC38 colon carcinoma irradiated with a single dose of 15 Gy. Finally, murine CT26 colon carcinoma tumors were immunofluorescently stained for STING and NF-κβ 24 and 48 h after IR with a clinically relevant fractionated regimen of 5 × 5 Gy. Results: Doses of 2, 4, 6, 8, and 10 Gy led to a dose-dependent decrease in proliferation and increased death of ECs. RNA sequencing analysis showed that the effects on the transcriptome of HUVECs were most pronounced 72 h after IR with 5 Gy, with 1014 genes (661 down-regulated and 353 up-regulated) being significantly differentially expressed. Irradiation with 5 Gy resulted in HUVEC activation, with up-regulation of the immune system and extracellular matrix genes, such as STING1 (log₂FC = 0.81) and SELE (log₂FC = 1.09), respectively; and down-regulation of cell cycle markers. Furthermore, IR led to the up-regulation of immune response- and extracellular matrix (ECM)-associated signaling pathways, including NF-κβ signaling and ECM–receptor interaction, which was also observed in the transcriptome of irradiated murine TECs in vivo. This was confirmed at the protein level with higher expressions of the EC activation-associated proteins STING, NF-κβ, and VCAM-1 in irradiated HUVECs and irradiated TECs in vivo. Conclusions: IR induces changes in ECs and TECs, supporting their activation in dose- and time-dependent manners, potentially contributing to the anti-tumor immune response, which may potentially increase the infiltration of immune cells into the tumor and thus, improve the overall efficacy of RT, especially in combination with immune checkpoint inhibitors. Full article

This study reports the use of single-cell RNA sequencing to evaluate B cells in the peripheral blood mononuclear cells (PBMCs) and intrathyroidal blood mononuclear cells of patients with Graves’ disease (GD) undergoing thyroidectomy. These cells were stimulated with overlapping peptides of thyroid autoantigens, including thyroid-stimulating hormone receptor (TSHR), thyroglobulin (Tg), and thyroid peroxidase (TPO). In PBMCs, naive B cells are characterized by IL6 and CXCR5, whereas memory B cells express IGHG1, IGHG2, and CD74. HLA-DMA, HLA-DRB1, IGHG, IGHM, CD74, CD79A, and MS4A1 expression increased in peptide-stimulated naive and memory B cells compared to those in the controls. Thyroid naive B cells are characterized by CD40 and TNFRSF13C, whereas memory B cells express IGHM, CD79A, and MS4A1. Thyroid B cells showed higher DUSP1, DUSP2, CD69, FOSB, RGS1, and immunoglobulin gene expression than control PBMCs and thyroid cells. B-cell receptor analysis revealed frequent IGHV3-23 and IGHV4-34 usage in controls, whereas IGHV4-34/IGHJ4 expression was increased in TSHR-stimulated groups. We concluded that B-cell responses to TSHR, Tg, and TPO differed and that changes in B-cell reactivity also occurred in PBMCs and the thyroid. Additionally, IGHV3-23 and IGHV4-34 may be associated with autoantibody production in GD. Full article

Background: Systemic lupus erythematosus (SLE) is a complex autoimmune disease with significant therapeutic challenges. Recent studies suggest that dihydroartemisinin (DHA), a traditional Chinese medicine known for its anti-malarial properties, may be beneficial for SLE treatment, although its precise mechanism remains unclear. This study aimed to investigate the effects of DHA on the cellular composition and molecular events of splenic T cells and B cells in MRL/lpr mice, a widely used SLE model. Methods: T cells and B cells isolated from the spleens of three DHA-treated mice and three control mice underwent single-cell RNA sequencing (scRNA-seq) using the 10× Genomics Chromium system. Comprehensive analyses included cell clustering, signaling pathway enrichment, pseudotime trajectory analysis, and cellular communication assessment using unbiased computational methods. Results: DHA treatment significantly reduced kidney inflammation and altered the proportions of splenic T cells and B cells, particularly decreasing plasma cells. Molecular profiling of effector CD4+ T cells showed a significant reduction in several inflammation-related signaling pathways in DHA-treated mice. Cellular communication analysis indicated altered interactions between effector CD4+ T cells and B cells in MRL/lpr mice after DHA treatment. Conclusions: Our findings reveal changes in cellular composition and signaling pathways in splenic T cells and B cells of MRL/lpr mice following DHA treatment. DHA may inhibit B-cell differentiation into plasma cells by modulating effector CD4+ T cells, potentially through the regulation of HIF1α and ligand–receptor interactions, enhancing our understanding of DHA’s mechanisms in SLE treatment. Full article

Virus-like nanoparticles (VNPs) based on Moloney murine leukemia virus represent a well-established platform for the expression of heterologous molecules such as cytokines, cytokine receptors, peptide MHC (pMHC) and major allergens, but their application for inducing protective anti-viral immunity has remained understudied as of yet. Here, we variably fused the wildtype SARS-CoV-2 spike, its receptor-binding domain (RBD) and nucleocapsid (NC) to the minimal CD16b-GPI anchor acceptor sequence for expression on the surface of VNP. Moreover, a CD16b-GPI-anchored single-chain version of IL-12 was tested for its adjuvanticity. VNPs expressing RBD::CD16b-GPI alone or in combination with IL-12::CD16b-GPI were used to immunize BALB/c mice intramuscularly and subsequently to investigate virus-specific humoral and cellular immune responses. CD16b-GPI-anchored viral molecules and IL-12-GPI were well-expressed on HEK-293T-producer cells and purified VNPs. After the immunization of mice with VNPs, RBD-specific antibodies were only induced with RBD-expressing VNPs, but not with empty control VNPs or VNPs solely expressing IL-12. Mice immunized with RBD VNPs produced RBD-specific IgM, IgG_2a and IgG₁ after the first immunization, whereas RBD-specific IgA only appeared after a booster immunization. Protein/peptide microarray and ELISA analyses confirmed exclusive IgG reactivity with folded but not unfolded RBD and showed no specific IgG reactivity with linear RBD peptides. Notably, booster injections gradually increased long-term IgG antibody avidity as measured by ELISA. Interestingly, the final immunization with RBD–Omicron VNPs mainly enhanced preexisting RBD Wuhan Hu-1-specific antibodies. Furthermore, the induced antibodies significantly neutralized SARS-CoV-2 and specifically enhanced cellular cytotoxicity (ADCC) against RBD protein-expressing target cells. In summary, VNPs expressing viral proteins, even in the absence of adjuvants, efficiently induce functional SARS-CoV-2-specific antibodies of all three major classes, making this technology very interesting for future vaccine development and boosting strategies with low reactogenicity. Full article

Background: In the adaptive immune response of the dromedary (Camelus dromedarius, Camdro), the T cell receptor (TR) repertoire of the gamma–delta (γδ) T cells is unusually diversified both by somatic hypermutation in rearranged TR gamma (TRG) and delta (TRD) genes and by the diversity in sequence and length of the third complementarity-determining region (CDR3) of the TRD chain. Methods: The purpose was to investigate, in the absence of 3D structures, the role of Camdro γδ T cells, focusing on the binding interactions at the interface between the V-gamma and V-delta domains, and in complex with the CD1D, a major histocompatibily class I (MH1)-like glycoprotein presenting lipid antigen in association with B2M. A combination of hypermutated TRG dromedary cDNA clones was paired with TRD clones bearing very long, long, or short CDR3s, all isolated from the spleen of a single animal. Results: The 3D models of the Camdro TRG_TRD/CD1D_B2M complexes were inferred using the Homo sapiens 3D structure and the ImMunoGeneTics (IMGT) numbering for V, C, and G domains, and investigated for binding interactions at the interface of the paired V-gamma_V-delta and at the interface with CD1D. Our results suggest that transcripts with long CDR3s may derive from a population of CD1D-restricted γδ T cells. Both the CD1D G-alpha1-like and G-alpha-2 like domain helices were contacted by both the V-gamma and V-delta CDR-IMGT loops. Conclusions: Our findings further emphasize the similarity between the γδ T cells population we analyzed in Camelus dromedarius and the CD1D-restricted γδ NKT cells in Homo sapiens. Full article