技术资料

Staphylococcal enterotoxins (SE) crosslink the MHC‐II on antigen‐presenting cells (APC) with the T‐cell receptor,inducing a polyclonal T‐cell response. Although APCs are the initial targets of SE and are critical in shaping subsequent T‐cell activation,the effects of SE on APC function remain poorly understood. This study investigates the immunomodulatory effects of staphylococcal enterotoxin A (SEA) on monocytes and their differentiation into monocyte‐derived dendritic cells (moDC) or macrophages (MDM). Transcriptomic analyses of human monocytes via RNA sequencing revealed SEA‐induced enrichment of gene pathways associated with inflammation,infection,and dermatitis,effects that were amplified in the presence of T cells. Phenotypic and functional characterization showed that SEA‐primed monocytes differentiated into MDM with an altered polarization,deviating from classical M1/M2 pathways. SEA‐primed MDM exhibited downregulation of key markers,including HLA‐DR,CD80,CD86,and PD‐L1. Functional assays demonstrated that SEA‐primed MDM pushed hyperinflammatory T‐cell responses,with significantly enhanced proliferation and IFN‐γ secretion. In contrast,following SEA‐priming,moDC retained robust antigen‐presenting capabilities and displayed enhanced expression of molecules involved in T‐cell interactions. These findings provide mechanistic insights into SEA‐mediated immune modulation,illustrating how SEA reprograms MDM functions and amplifies proinflammatory T‐cell responses. This advances our understanding of superantigen‐driven immune interactions,offering a foundation for developing therapeutic strategies to mitigate superantigen‐mediated immune conditions. Staphylococcal enterotoxin A (SEA) alters monocyte differentiation and function,while preserving T cell stimulatory capacity. SEA‐primed macrophages downregulate antigen‐presenting markers yet drive heightened T‐cell proliferation and IFN‐γ secretion. These findings reveal mechanisms of SEA‐mediated immune modulation and superantigen‐driven inflammation. View Publication

Pre-clinical research on B and NK cell development relies on murine stromal cell-based systems with reduced physiological relevance and clinical applicability. A serum-free,fully humanized co-culture system utilizing human bone marrow-derived mesenchymal stromal cells (BM-MSCs) was developed to differentiate CB-CD34+ cells towards B and NK cell lineages. Differentiation dynamics were monitored via flow cytometry,with immunophenotypic analysis tracking progression from progenitors to mature cells. The system generated CD19+ IgM+ immature B cells and CD56+ CD16+ NK cells,recapitulating fetal stages of human lymphopoiesis. Serum-free media conditions ensured reproducibility and high overall yield of CD19+ B (35 ± 5.32%) and CD56+ NK (28.46 ± 7.01%) cell progenitors. Flow cytometry identified distinct population peaks,confirming temporal control over differentiation. This clinically relevant platform addresses the limitations of traditional models by providing a more physiologically accurate human microenvironment. The serum-free system supports applications in disease modeling,genotoxic compound screening,and mutational studies of hematopoiesis. By enabling scalable production of B and NK cells it aims to accelerate translational research for immunodeficiencies,cancer immunotherapy,and hematopoietic disorders. View Publication

Graft‐versus‐host disease is mediated by donor‐derived T cells reactive against the recipient's broadly expressed minor histocompatibility antigens (mHA). Regulatory T cells (Treg) have been explored as a therapeutic approach for chronic GVHD (cGVHD). The promising results from polyclonal Treg trials in this setting have led us to develop a Treg product specific for mismatched minor antigens between patient and donor (mTreg),circumventing broad immune suppression risks. HLA‐matched siblings of opposite sexes were used to obtain the sister's CD4+CD25hiCD127low Treg for co‐culture with the respective brother's dendritic cells as a source of mismatched mHA. We have established the optimal culture conditions resulting in the highest mTreg proliferation and viability. Comprehensive phenotyping during the ex vivo selection shows PD‐1,CTLA‐4,CD39 and HLA‐DR expression. Transcriptomic analysis revealed a switch in metabolic process,and up‐regulation of functional Treg genes. Furthermore,mTreg possess specific and potent suppressive activity,in which there is a dependency on cell‐to‐cell contact and a role for HLA class II expression on mTreg. This protocol would allow the generation of Treg specific to an array of mHA from the recipient's healthy tissues,likely providing a directed and strong suppression of cGVHD. We optimised a protocol for mHA‐specific Treg (mTreg) selection in an HLA‐matched context while defining its phenotype,transcriptional state and function. mTreg were highly activated and exerted specific,HLA class II‐,contact‐dependent suppression. This protocol can be explored as a highly personalised antigen‐specific Treg‐based therapy in future clinical trials for cGVHD. View Publication

Adoptive cell therapy (ACT) targeting tumor-specific antigens holds promise for solid tumors,but limited neoantigen presentation remains a key barrier to efficacy. Here,we identify and characterize a T cell receptor (TCR),T104,for the KRAS.G12V mutation,a prevalent neoantigen in colorectal,lung,and pancreatic cancers. TCR-T104 selectively recognizes and kills KRAS.G12V-expressing tumor cells. Combining T cell therapy with lymphodepleting chemotherapy significantly enhances tumor cell killing,particularly by TCR-T cells,tumor-infiltrating lymphocytes (TILs),and T cell engager antibodies across multiple cancer types and target antigens. Mechanistically,chemotherapy upregulates immunoproteasome activity and human leukocyte antigen (HLA)-I surface expression. HLA-immunopeptidome analyses reveal that chemotherapy remodels the antigenic landscape across tumor cell lines and in vivo models,increasing peptide abundance and hydrophobicity while altering proteasomal cleavage preferences. These findings establish a synergistic role for chemotherapy in enhancing neoantigen presentation and T cell-mediated tumor recognition and suggest that fine-tuning these regimens could improve ACT efficacy,particularly in tumors with low-abundance neoantigens. View Publication

Background and Objectives: Serum myelin oligodendrocyte glycoprotein (MOG) antibodies are a hallmark of the newly defined neuroinflammatory disease entity MOG antibody–associated disease (MOGAD). Yet,the lack of patient-derived recombinant human MOG (hMOG)–reactive autoantibodies limits investigations into the molecular mechanisms by which these autoantibodies mediate CNS pathology,thereby hindering rational therapeutic approaches. To understand the origins and disease-relevant mechanisms of autoantibodies in MOGAD,we generated and characterized monoclonal anti-hMOG antibodies (MOG-mAbs) from circulating B cells of patients with MOGAD.Methods: We isolated MOG-specific B-cell receptor (BCR) sequences from unique circulating B-cell clones of 6 patients with MOGAD using an antigen selection approach. BCR sequences were expressed as immunoglobulin (Ig)G1 antibodies,and their molecular features,epitope specificity,and binding to MOG isoforms were investigated. The MOG-mAbs’ ability to mediate antibody-dependent cellular phagocytosis (ADCP),natural killer (NK) cell–mediated antibody-dependent cellular cytotoxicity (ADCC),and complement-dependent cytotoxicity (CDC) toward MOG-expressing cells was assessed by live cell-based assays.Results: Of the 15 MOG-mAbs generated,4 revealed evidence of affinity maturation,whereas the remaining 11 were germline encoded. Binding capacities to hMOG varied considerably,with the most frequent putative epitope mapping to a region that includes residue P42. The efficacy of these antibodies in mediating ADCP,ADCC,and CDC of MOG-expressing cells was heterogeneous and associated with their binding characteristics to MOG and its isoforms.Discussion: Taken together,the molecular characteristics and binding patterns of these patient-derived MOG-mAbs reveal a diverse repertoire of MOG-binding autoantibodies with pathogenic capacity in vitro. Consequently,these well-characterized patient autoantibodies offer a foundation for developing in vivo models of MOGAD,serve as tools to standardize diagnostic assays,and guide development of therapeutic strategies targeting either B cells or autoantibodies and their effector functions. View Publication

Francisella tularensis (Ft),a Gram-negative bacterium that causes tularemia,possesses a non-inflammatory atypical LPS (LPSFt) that is highly immunogenic through unknown mechanism. We previously showed that immunization with LPSFt,a type 2 T-independent (TI) antigen,elicits protective LPSFt-specific IgM (IgMFt) and IgG3Ft by B1 cells in a mechanism dependent on the IL-5 produced by innate lymphoid cells type 2 (ILC2). Here,we examined the role of complement in the B1 cells’ response against LPSFt. C3-/-,C1q-/- and C4-/- mice immunized with LPSFt failed to produce IgMFt and IgG3Ft. In contrast,the response of Cfb-/- and Mbl1/Mbl2-/- mice was comparable to that of WT mice. Thus,activation of the classical complement cascade,but not the alternative or the Mannose Binding Lectin pathway,is required for activation of B1 cells and production of LPSFt-specific antibodies. Complement activation generates the C3d fragment,which opsonizes antigens for recognition by complement receptor-2 (CR2),and the C3a and C5a anaphylatoxins. Our results show that C3d opsonized LPSFt and that the response to immunization was dependent on CR2 expression by B1 cells. Importantly,the response to LPSFt immunization was also drastically decreased in C3ar1-/-,but not in C5ar1-/- mice. C3a induced IL-5 in ILC2,which supported B1 cells activation. Decreased antibody production in C3ar1-/- and Cr2-/- mice correlated with increased susceptibility to tularemia. Together,these results demonstrate that the high immunogenicity of LPSFt depends on two effector mechanisms triggered by activation of the classical complement pathway: 1) tagging of LPSFt with C3d fragment,leading to its interaction with CR2 expressed by B1 cells; 2) production of the anaphylatoxin C3a that stimulated IL-5 secretion by ILC2. Our study increases our understanding of the B1 cells’ response to TI-2 antigens and identifies two complement effector mechanisms that can be harnessed for therapeutic interventions. Author summaryThe lipopolysaccharide (LPS) of the bacterium Francisella tularensis strongly stimulates B cells for antibody production independently of T cell help through unknown mechanism. In the present study we examined the role of the complement cascade in this process. We found that production of antibodies against this LPS depends on activation of the classical complement pathway but not the MBL-dependent lectin or the alternative pathways. Following complement activation,LPS became tagged with the C3d complement fragment leading to its interaction with the complement receptor CR2 expressed by B cells. Complement activation also resulted in production of the anaphylatoxin C3a that was required for B cells activation,possibly through induction of IL-5 by innate lymphoid cells 2. Our study increases our understanding of the B cells’ response to T-independent antigens and identifies two complement effector mechanisms that can be harnessed for therapeutic interventions. View Publication

SF3B1,a component of the U2 snRNP pre-mRNA splicing factor,plays a critical role in splicing and is frequently mutated in cancer,particularly hematologic malignancies. We investigated the effects of the most common SF3B1 mutation,heterozygous substitution of Lysine 700 to Glutamate (K700E),in human embryonic stem cells (hESC),using CRISPR-Cas9 to generate heterozygous SF3B1K700E clones. Interestingly,we observed the upregulation of several key transcription regulators associated with hematopoiesis and a broad range of immune genes in SF3B1K700E hESCs. Despite differences in the transcriptional and splicing profiles between hESC and myelodysplastic syndrome (MDS) cells harboring the SF3B1K700E mutation,several common immune gene programs were identified in both cell types. To elucidate the molecular mechanisms underlying dysregulated gene expression in SF3B1K700E hESCs,we mapped actively engaged RNA polymerase II (RNA Pol II) using Precision Run-On sequencing (PRO-seq). These analyses revealed that the SF3B1K700E mutation alters RNA Pol II elongation properties. Specifically,we observed a general increase in pause release in SF3B1K700E hESCs,consistent with recent work in leukemia cells suggesting that the SF3B1K700E mutation affects early transcription elongation. Taken together,our study identifies several candidate genes that could contribute to the SF3B1 mutated phenotype and clarifies the role for the U2 snRNP and pre-spliceosome assembly on transcription by RNA Pol II. Further,our data suggest that mutations of SF3B1 impact immune gene expression independent of cell type,providing new insights into the role of SF3B1K700E in hematologic malignancies. View Publication

Lens transparency relies on proper intercellular communication. Exosomes are crucial mediators of intercellular communication and play a key role in organ homeostasis and development. However,their presence and dynamics in the lens remain unclear. Here,we report endogenous exosomes in the zebrafish lens using cryaa-driven Cd63-AcGFP labeling. Live imaging revealed dynamic exosome movement within lens cells and their potential transfer to adjacent tissues. Additionally,we found that the biogenesis of Cd63+ exosomes in the lens is regulated by the Syntenin-a pathway. And Syntenin-a knockdown delayed lens development by impairing lens cell differentiation,highlighting the potential role of lens cell–derived exosomes. Furthermore,ROR1+ lens progenitor cell-derived extracellular vesicles promoted lentoid differentiation in vitro,with proteomic analysis suggesting underlying mechanisms. Overall,our study addresses the gap in direct observation of endogenous lens exosomes,providing foundational insights into lens pathophysiology and a potential strategy for modulating the lens microenvironment. Visualization of endogenous exosomes in the zebrafish lens reveals their dynamic roles in intercellular communication and development,with Syntenin-a–regulated exosome biogenesis influencing lens cell differentiation. View Publication

The T-cell receptor (TCR) initiates T-lymphocyte activation,but the mechanism of TCR activation remains uncertain. Here,we present cryogenic electron microscopy structures for the unliganded and human leukocyte antigen (HLA)-bound human TCR–CD3 complex in nanodiscs that provide a native-like lipid environment. Distinct from the open and extended conformation seen in detergent,the unliganded TCR–CD3 in nanodiscs adopts two related closed and compacted conformations that represent its physiologic resting state in vivo. By contrast,the HLA-bound complex adopts the open and extended conformation,and conformation-locking disulfide mutants show that ectodomain opening is necessary for maximal ligand-dependent T-cell activation. These structures also reveal conformation-dependent protein–lipid and glycan–glycan interactions within the TCR. Together,these results establish allosteric conformational change during TCR activation,reveal avenues for immunotherapeutic engineering,and highlight the importance of native-like lipid environments for membrane protein structure determination. The T-cell receptor (TCR) activation mechanism has remained uncertain. Here,the authors present molecular structures for the apo and ligand-bound human TCR–CD3 complex in lipid nanodiscs,revealing large conformational changes during activation. View Publication

MYC-driven medulloblastoma (MB) is a highly aggressive brain tumor with poor prognosis and limited treatment options. Through CRISPR-Cas9 screening,we identify the Mediator-associated kinase CDK8 as a critical regulator of MYC-driven MB. Both genetic loss and pharmacological inhibition of CDK8 impair MB tumor growth. Moreover,we find that CDK8 cooperates with MYC to sustain the MYC-mediated translational program,as CDK8 depletion induces pronounced transcriptional changes in translation-associated gene sets,reduces ribosome biogenesis,and impairs protein synthesis. Mechanistically,CDK8 regulates the occupancy of RNA polymerase II at specific chromatin loci,facilitating epigenetic alterations that promote the transcription of ribosomal genes. Furthermore,combined inhibition of CDK8 and mTOR synergistically enhances therapeutic efficacy in vivo,leading to more pronounced tumor growth suppression. Overall,our findings establish a functional link between CDK8-mediated transcriptional regulation and mRNA translation,suggesting a promising therapeutic approach targeting protein synthesis for MYC-driven MB. MYC-driven medulloblastoma is an aggressive pediatric tumor with limited treatment options. Here,the authors show that CDK8 regulates ribosome biogenesis and that combined inhibition of CDK8 and mTOR demonstrates therapeutic efficacy in mouse models of this cancer. View Publication

Induced pluripotent stem cells (iPSCs) are commonly used to model human genetic diseases. Two main strategies are used. The first involves making iPSC lines from individual cases with a disease,and the second involves making disease-relevant gene edits in established iPSC lines. Because generating gene-edited lines is time consuming and expensive,most studies begin with one starting iPSC stock line and evaluate several gene-edited sublines. The current studies focus on gene-editing to model Lesch–Nyhan disease (LND),which is caused by mutations in the HPRT1 gene. The same pathogenic c.508C>T edit was made in four well-established stock lines,and three gene-edited lines were isolated from each. RNA sequencing (RNAseq) was,then,used to evaluate the impact of the gene edit. Gene-edited lines were compared to their corresponding stock lines,as well as to each other. An aggregate analysis of all lines combined was also conducted to determine the most robust findings across all lines. Results from gene editing were further compared with iPSC lines derived from individual cases with LND,to determine how closely findings from gene editing match results obtained with case-derived lines. There were two main findings. First,the same gene edit has a different impact on gene expression when starting with different starting stock lines. Second,the gene editing strategy does not produce the same results as the case-derived strategy. Potential explanations for these differences are addressed,along with the relevance of these two different strategies for disease modeling. View Publication

Background: Chronic myocarditis (CMYO) progresses to fibrosis and heart failure,yet no therapies effectively target fibrosis. Fibroblast activation protein (FAP) marks pathogenic myofibroblasts,but its therapeutic potential remains unexplored in inflammatory settings.Methods: Using bulk/scRNA-seq of human myocarditis samples,we identified FAP as a fibrosis-specific marker. We engineered FAP-targeted CAR-T (FAP.CAR-T) cells and tested their efficacy in autoimmune (EAM) and viral (CVB3) myocarditis models. Human cardiac organoids (hCOs) treated with IL-17A modeled inflammatory fibrosis.Results: FAP expression correlated with fibrosis severity in patients (r = 0.96,P = 0.0028). In EAM and CVB3 models,FAP.CAR-T cells reduced fibrosis by 65% and 55%,respectively (P < 0.001),restored ejection fraction to higher than 65%. hCOs treated with FAP.CAR-T cells showed 55% less fibrosis (P < 0.05). No toxicity was observed in healthy mice.Conclusions: FAP.CAR-T cells eliminate fibrosis-driving myofibroblasts,reversing cardiac dysfunction in chronic myocarditis. This strategy,validated in human organoids,offers translatable immunotherapy for fibrosis-driven heart disease. View Publication