[Construction and Optimization of CD19 Chimeric Antigen Receptor T Cells Derived from C57BL/6J Mice].

OBJECTIVE: To explore the stimulation conditions, optimal culture time and infection time of C57BL/6J mice CD3+ T cells in vitro, so as to improve the infection efficiency of CD19 chimeric antigen receptor T cells (mCD19 CAR-T). METHODS: Purified C57BL/6J mice CD3+ T cells were cultured in anti-CD3/CD28 coated, anti-CD3 coated+soluble anti-CD28 and anti-CD3 coated, respectively. The cells were stimulated in above three conditions for 12 h and 24 h, following with 24 h, 48 h and 72 h incubation and then the number of cell clones was recorded. C57BL/6J mice CD3+ T cells were stimulated for 12 h, 24 h, and 36 h under the above three conditions, then interleukin (IL)-2 (100 U/ml) was added. The number of cell clones was recorded under microscope at 24 h, 48 h, and 72 h of culture. After 24 h of stimulation, CD3+ T cells derived from C57BL/6J mice were infected with retrovirus for 48 h to establish mCD19 CAR-T cells, and the percentage of GFP+ CAR-T cells was detected by flow cytometry. RESULTS: The infection efficiency of mCD19 CAR-T cells derived from C57BL/6J mice was only 5.23% under the optimized conditions of mCD19 CAR-T cells derived from BALB/c mice. The number of clones of C57BL/6J mice CD3+ T cells was the highest in anti-CD3 coated+soluble anti-CD28 group after stimulated for 24 h and followed cultured for 48 h. After 24 hours of stimulation under the above conditions and 48 hours of culture with IL-2, the number of T cell proliferating clones in the anti-CD3 coated+soluble anti-CD28 group was significantly increased compared with the same group without IL-2, and the infection efficiency of CAR-T cells in this group reached 17.63%±4.17%. CONCLUSION: The optimal conditions for constructing CAR-T cells from C57BL/6J mice CD3+ T cells are different from those of BABL/c mice. T cells stimulated by anti-CD3 coated+soluble anti-CD28+IL-2 can obtain mCD19 CAR-T cells with the highest efficiency after retrovirus infection.

The immunologic abnormalities in patients with paroxysmal nocturnal hemoglobinuria are associated with disease progression.

OBJECTIVES: To suggest the presence of a hyperimmune state in patients, and indicate that immune system attack on glycosylphosphatidylinositol (+) (GPI+) cells while escaping GPI- cell immunity. METHODS: We retrospective the immune cell subtypes in peripheral blood from 25 patients visiting Tianjin Medical University General Hospital, Tianjin, China, with classical paroxysmal nocturnal hemoglobinuria (PNH) and 50 healthy controls. RESULTS: The total CD3+ and CD3+CD8+ cell levels were higher in patients with PNH. The CD3+ cells are positively, correlated with lactate dehydrogenase (LDH; r=0.5453, p=0.0040), indirect bilirubin (r=0.4260, p=0.0379) and Flear- cells in monocytes (r=0.4099, p=0.0303). However, a negative correlation was observed between CD3+ cells and hemoglobin (r= -0.4530, p=0.0105). The total CD19+ cells decreased in patients, and CD19+ cells were negatively correlated with LDH (r= -0.5640, p=0.0077) and Flear- cells in monocytes (r= -0.4432, p=0.0341). Patients showed an increased proportion of total dendritic cells (DCs), with a higher proportion of myeloid DCs (mDCs) within the DC population. Moreover, the proportion of mDC/DC was positively correlated with CD59- cells (II + III types) in red cells (r=0.7941, p=0.0004), Flear- cells in granulocytes (r=0.5357, p=0.0396), and monocytes (r=0.6445, p=0.0095). CONCLUSION: Our results demonstrated that immune abnormalities are associated with PNH development.

Inducible IL-2 production and IL-2+ cell expansion are landmark events for T-cell activation of teleost.

As a multipotent cytokine, interleukin (IL)-2 plays important roles in activation, differentiation and survival of the lymphocytes. Although biological characteristics and function of IL-2 have been clarified in several teleost species, evidence regarding IL-2 production at the cellular and protein levels is still scarce in fish due to the lack of reliable antibody. In this study, we developed a mouse anti-Nile tilapia IL-2 monoclonal antibody (mAb), which could specifically recognize IL-2 protein and identify IL-2-producing lymphocytes of tilapia. Using this mAb, we found that CD3+ T cells, but not CD3- lymphocytes, are the main cellular source of IL-2 in tilapia. Under resting condition, both CD3+CD4-1+ T cells and CD3+CD4-1- T cells of tilapia produce IL-2. Moreover, the IL-2 protein level and the frequency of IL-2+ T cells significantly increased once T cells were activated by phytohemagglutinin (PHA) or CD3 plus CD28 mAbs in vitro. In addition, Edwardsiella piscicida infection also induces the IL-2 production and the expansion of IL-2+ T cells in the spleen lymphocytes. These findings demonstrate that IL-2 takes part in the T-cell activation and anti-bacterial adaptive immune response of tilapia, and can serve as an important marker for T-cell activation of teleost fish. Our study has enriched the knowledge regarding T-cell response in fish species, and also provide novel perspective for understanding the evolution of adaptive immune system.

A specific enterotype derived from gut microbiome of older individuals enables favorable responses to immune checkpoint blockade therapy.

Immunotherapy has revolutionized cancer treatment, but inconsistent responses persist. Our study delves into the intriguing phenomenon of enhanced immunotherapy sensitivity in older individuals with cancers. Through a meta-analysis encompassing 25 small-to-mid-sized trials of immune checkpoint blockade (ICB), we demonstrate that older individuals exhibit heightened responsiveness to ICB therapy. To understand the underlying mechanism, we reanalyze single-cell RNA sequencing (scRNA-seq) data from multiple studies and unveil distinct upregulation of exhausted and cytotoxic T cell markers within the tumor microenvironment (TME) of older patients. Recognizing the potential role of gut microbiota in modulating the efficacy of immunotherapy, we identify an aging-enriched enterotype linked to improved immunotherapy outcomes in older patients. Fecal microbiota transplantation experiments in mice confirm the therapeutic potential of the aging-enriched enterotype, enhancing treatment sensitivity and reshaping the TME. Our discoveries confront the prevailing paradox and provide encouraging paths for tailoring cancer immunotherapy strategies according to an individual's gut microbiome profile.

An optimized non-T cell transfection system based on HEK293FT cells for CD3ζ phosphorylation and ubiquitination.

CD3ζ is part of the T cell receptor (TCR)/CD3 complex that plays a critical role in antigen recognition and subsequent T cell activation. Understanding the mechanisms that regulate CD3ζ can provide new insights into the T cell-mediated immune responses. However, it is challenging to deliver exogenous genes into T cells for functional and mechanistic analyses. To this end, we established a non-T cell transfection system based on HEK293FT cells to screen for candidate regulatory proteins. The transfection was optimized using relatively high confluent cultures and the transfection reagent PolyJet™. Pervanadate (PV) treatment sustained tyrosine phosphorylation of CD3ζ, and facilitated the subsequent activation-dependent ubiquitination by E3 ligase Cbl-b in the HEK293FT system. Lck and Zap70 kinases enhanced the levels of phosphorylated CD3ζ in the presence of PV. We compared the effects of E3 ligases and the corresponding adaptor proteins on activation-dependent ubiquitination of CD3ζ in the PV-stimulated cells, and found that Cbl-b was most effective. Taken together, we have demonstrated that a non-T cell transfection system based on PV-treated HEK293FT cells could effectively mimic CD3ζ phosphorylation and ubiquitination and is a promising model for studying the role of CD3ζ signaling in T cell activation.

Immunochemistry-based quantification of tumor-infiltrating lymphocytes and immunoscore as prognostic biomarkers in bladder cancer.

BACKGROUND: Tumor-infiltrating lymphocytes (TILs) and the derived immunoscore (IS) have gained considerable attention over the last decade as prognostic markers in many solid cancers. However, in bladder cancer (BC), their prognostic value is not clearly established. METHODS: The present study aimed to quantify the TILs rates in BC, assess the derived immunoscore, and investigate their prognostic value. An immunochemistry-based quantification of the different subtypes of TILS was performed on paraffin-embedded blocks from patients with invasive urothelial carcinoma of the bladder. We have assessed the rates of TILs, respectively, on peri-tumoral (PT) and intra-tumoral (IT) areas and calculated for each case the corresponding IS which is the index: CD8+/CD3+ TILs. The IS was then classified as low (I0, I1) or high (I2, I3, I4). We included 30 cases in the analysis. RESULTS: The median age of patients was 65 years with a sex ratio of 9. TILs densities and distribution were significantly variable between IT and PT areas CD3+ (p = 0.03) and CD8+ (p = 0.004) with the highest rates on the PT areas. In univariate analysis, a low density of CD8+ TILs was significantly associated with an advanced age (p = 0.05), with the presence of lympho-vascular invasion (p = 0.02) and with the absence of specific histological subtype (p = 0.05). A low immunoscore was significantly associated with the presence of lympho-vascular invasion (p = 0.004). No significant association was found between TILs subpopulations, the IS, and the other clinicopathological and survival data. The overall survival (OS) and disease-free survival (DFS) medians were slightly superior in highly T (CD3+/CD8+)-cell infiltrated tumors as well as tumors with a high IS densities. However, the univariate analysis showed that TILs and immunoscore did not impact overall survival (OS) and disease-free survival (DFS). CONCLUSION: TILs and immunoscore might be effective prognostic tools in BC. However, standardized quantification methods and further investigation on larger samples are highly recommended to definitively attest the prognostic value of TILs and IS in BC.

Antigen/HLA-agnostic strategies for Characterizing Tumor-responsive T cell receptors in PDAC patients via single-cell sequencing and autologous organoid application.

Characterization of tumor-responsive T cell receptors (TCRs) is a critical step in personalized TCR-T cell therapy, and remains challenging for pancreatic ductal adenocarcinoma (PDAC). Here we report a proof-of-concept study to identify and validate antitumor TCRs in two representative PDAC patients using ultradeep single-cell TCR/RNA sequencing and autologous organoids, and reveal the phenotypic dynamics of TCR repertoire in different T cell expansions from the same patient. We first performed comparative sequencing on freshly harvested peripheral blood mononuclear cells (PBMCs) and uncultured tumor infiltrating lymphocytes (TILs), followed by reactivity tests of TIL-enriched TCRs with autologous organoids, in which two tumor-responsive TCRs were successfully characterized and the corresponding TILs were mostly tissue-resident memory-like T cells, and partially expressed both naïve and exhausted T cell markers. For the PDAC patient without high-quality TILs, PBMCs were cultured with neoantigen peptide (KRASG12D), organoids, or anti-CD3 antibody in presence, and experienced extensive clonal expansions within ten days. All derived PBMCs were sequenced in parallel (>82,000 cells), and TCRs enriched in both peptide- and organoid-experienced, but not anti-CD3-treated CD8 T cells, were assessed for their reactivity to antigen-presenting cells (APCs) and organoids, in which three neoantigen-reactive TCRs were identified as tumor-responsive, and the corresponding T cells were characterized by mixed transcriptional signatures including but not limited to typical exhausted T cell markers. Together, our study revealed that the combination of ultradeep single-cell sequencing and organoid techniques enabled rapid characterization of tumor-responsive TCRs for developing practical personalized TCR-T therapy in an antigen/human leukocyte antigen (HLA)-agnostic manner.

Machine learning constructs a T cell-related signature for predicting prognosis and drug sensitivity in ovarian cancer.

BACKGROUND: The leading cause of death related to gynecologic cancer is ovarian cancer, which typically has a poor prognosis. T cells are referred to as key mediators of immunosurveillance and tumor eradication, and unbalanced regulation or lack of T cells in tumors result in immunotherapy resistance. METHODS: The identification of T cell related markers depended on single-cell RNA-seq analysis. Using data from multiple datasets, including TCGA, GSE14764, GSE26193, GSE26712, and GSE140082, we constructed a prognostic signature called TRS (T cell-related signature) using 10 different machine learning algorithms. The correlation between TRS and drug sensitivity were analyzed using the data from GSE91061 and IMvigor210 dataset. RESULTS: PlsRcox method based TRS was as a risk factor for the clinical outcome of ovarian cancer patients. In comparison with stage, grade and many prognostic signatures, the performance of our TRS in evaluating the clinical outcome was better in ovarian cancer. TRS-based risk score showed distinct association with the level of ESTIMATE score, immune-related function score and immune cells. Moreover, TRS could be used to predict the immunotherapy response and chemotherapy response in ovarian cancer. CONCLUSION: In conclusion, we constructed a powerful TRS in ovarian cancer, which could accurately predict the clinical outcome of patients and be used to predict the immunotherapy response and chemotherapy response.

Integrative temporal multi-omics reveals uncoupling of transcriptome and proteome during human T cell activation.

Engagement of the T cell receptor (TCR) triggers molecular reprogramming leading to the acquisition of specialized effector functions by CD4 helper and CD8 cytotoxic T cells. While transcription factors, chemokines, and cytokines are known drivers in this process, the temporal proteomic and transcriptomic changes that regulate different stages of human primary T cell activation remain to be elucidated. Here, we report an integrative temporal proteomic and transcriptomic analysis of primary human CD4 and CD8 T cells following ex vivo stimulation with anti-CD3/CD28 beads, which revealed major transcriptome-proteome uncoupling. The early activation phase in both CD4 and CD8 T cells was associated with transient downregulation of the mRNA transcripts and protein of the central glucose transport GLUT1. In the proliferation phase, CD4 and CD8 T cells became transcriptionally more divergent while their proteome became more similar. In addition to the kinetics of proteome-transcriptome correlation, this study unveils selective transcriptional and translational metabolic reprogramming governing CD4 and CD8 T cell responses to TCR stimulation. This temporal transcriptome/proteome map of human T cell activation provides a reference map exploitable for future discovery of biomarkers and candidates targeting T cell responses.

Influence of different conjugation methods for activating antibodies on polymeric nanoparticles: Effects for polyclonal expansion of human CD8+ T cells.

Particle-based systems have become a state-of-the-art method for in vitro expanding cytotoxic T cells by tailoring their surface with activating molecules. However, commonly used methods utilize facile carbodiimide chemistry leading to uncontrolled orientation of the immobilized antibodies on the particle surface that can lead to poor binding to target cells. To address this, selective coupling strategies utilizing regioselective chemical groups such as disulfide bridges offer a simple approach. In this work we present a set of methods to investigate the effect of polymeric nanoparticles, conjugated with either regioselective- or randomly-immobilized antiCD3 and antiCD28 antibodies, on the activation potential, expansion and expression of activation markers in T cells. We show that nanoparticles with well-oriented monovalent antibodies conjugated via maleimide require fewer ligands on the surface to efficiently expand T cells compared to bivalent antibodies randomly-immobilized via carbodiimide conjugation. Analysis of the T cell expression markers reveal that the T cell phenotype can be fine-tuned by adjusting the surface density of well-oriented antibodies, while randomly immobilized antibodies showed no differences despite their ligand density. Both conjugation techniques induced cytotoxic T cells, evidenced by analyzing their Granzyme B secretion. Furthermore, antibody orientation affects the immunological synapse and T cell activation by changing the calcium influx profile upon activation. Nanoparticles with well-oriented antibodies showed lower calcium influx compared to their bivalent randomly-immobilized counterparts. These results highlight the importance of controlling the antibody density and orientation on the nanoparticle surface via controlled coupling chemistries, helping to develop improved particle-based expansion protocols to enhance T cell therapies.

Teclistamab: Mechanism of action, clinical, and translational science.

Multiple myeloma (MM) remains incurable despite improvements in treatment options. B-cell maturation antigen (BCMA) is predominantly expressed in B-lineage cells and represents a promising new target for MM. Teclistamab (TECVAYLITM ) is the first T-cell redirecting bispecific antibody approved for patients with MM. Targeting both CD3 receptor complex on T cells and BCMA on myeloma cells, teclistamab leads to T-cell activation and subsequent lysis of BCMA+ cells. The recommended dose of teclistamab is 1.5 mg/kg subcutaneous weekly after two step-up doses of 0.06 and 0.3 mg/kg, which was selected after review of safety, efficacy, pharmacokinetic, and pharmacodynamic data. Exposure-response analyses of efficacy and safety data were also used to confirm the teclistamab dose. Teclistamab resulted in a high rate of deep and durable responses (63% overall response, 45.5% complete response or better, with 22 months median duration of response) in patients with triple-exposed relapsed/refractory MM. Common adverse reactions included cytokine release syndrome, hematologic abnormalities, and infections. Teclistamab is currently being investigated as monotherapy as well as combination therapy across different MM indications.

Integrative analysis of single-cell and bulk RNA-sequencing data revealed T cell marker genes based molecular sub-types and a prognostic signature in lung adenocarcinoma.

Immunotherapy has emerged as a promising modality for addressing advanced or conventionally drug-resistant malignancies. When it comes to lung adenocarcinoma (LUAD), T cells have demonstrated significant influence on both antitumor activity and the tumor microenvironment. However, their specific contributions remain largely unexplored. This investigation aimed to delineate molecular subtypes and prognostic indicators founded on T cell marker genes, thereby shedding light on the significance of T cells in LUAD prognosis and precision treatment. The cellular phenotypes were identified by scrutinizing the single-cell data obtained from the GEO repository. Subsequently, T cell marker genes derived from single-cell sequencing analyses were integrated with differentially expressed genes from the TCGA repository to pinpoint T cell-associated genes. Utilizing Cox analysis, molecular subtypes and prognostic signatures were established and subsequently verified using the GEO dataset. The ensuing molecular and immunological distinctions, along with therapy sensitivity between the two sub-cohorts, were examined via the ESTIMATE, CIBERSORT, and ssGSEA methodologies. Compartmentalization, somatic mutation, nomogram development, chemotherapy sensitivity prediction, and potential drug prediction analyses were also conducted according to the risk signature. Additionally, real-time qPCR and the HPA database corroborated the mRNA and protein expression patterns of signature genes in LUAD tissues. In summary, this research yielded an innovative T cell marker gene-based signature with remarkable potential to prognosis and anticipate immunotherapeutic outcomes in LUAD patients.

T-cell stimulating vaccines empower CD3 bispecific antibody therapy in solid tumors.

CD3 bispecific antibody (CD3 bsAb) therapy is clinically approved for refractory hematological malignancies, but responses in solid tumors have been limited so far. One of the main hurdles in solid tumors is the lack of sufficient T-cell infiltrate. Here, we show that pre-treatment vaccination, even when composed of tumor-unrelated antigens, induces CXCR3-mediated T-cell influx in immunologically 'cold' tumor models in male mice. In the absence of CD3 bsAb, the infiltrate is confined to the tumor invasive margin, whereas subsequent CD3 bsAb administration induces infiltration of activated effector CD8 T cells into the tumor cell nests. This combination therapy installs a broadly inflamed Th1-type tumor microenvironment, resulting in effective tumor eradication. Multiple vaccination formulations, including synthetic long peptides and viruses, empower CD3 bsAb therapy. Our results imply that eliciting tumor infiltration with vaccine-induced tumor-(un)related T cells can greatly improve the efficacy of CD3 bsAbs in solid tumors.

CD3 downregulation identifies high-avidity human CD8 T cells.

CD8 T cells recognize infected and cancerous cells via their T-cell receptor (TCR), which binds peptide-MHC complexes on the target cell. The affinity of the interaction between the TCR and peptide-MHC contributes to the antigen sensitivity, or functional avidity, of the CD8 T cell. In response to peptide-MHC stimulation, the TCR-CD3 complex and CD8 co-receptor are downmodulated. We quantified CD3 and CD8 downmodulation following stimulation of human CD8 T cells with CMV, EBV, and HIV peptides spanning eight MHC restrictions, observing a strong correlation between the levels of CD3 and CD8 downmodulation and functional avidity, regardless of peptide viral origin. In TCR-transduced T cells targeting a tumor-associated antigen, changes in TCR-peptide affinity were sufficient to modify CD3 and CD8 downmodulation. Correlation analysis and generalized linear modeling indicated that CD3 downmodulation was the stronger correlate of avidity. CD3 downmodulation, simply measured using flow cytometry, can be used to identify high-avidity CD8 T cells in a clinical context.

Tuning the potency and selectivity of ImmTAC molecules by affinity modulation.

T-cell-engaging bispecifics have great clinical potential for the treatment of cancer and infectious diseases. The binding affinity and kinetics of a bispecific molecule for both target and T-cell CD3 have substantial effects on potency and specificity, but the rules governing these relationships are not fully understood. Using immune mobilizing monoclonal TCRs against cancer (ImmTAC) molecules as a model, we explored the impact of altering affinity for target and CD3 on the potency and specificity of the redirected T-cell response. This class of bispecifics binds specific target peptides presented by human leukocyte antigen on the cell surface via an affinity-enhanced T-cell receptor and can redirect T-cell activation with an anti-CD3 effector moiety. The data reveal that combining a strong affinity TCR with an intermediate affinity anti-CD3 results in optimal T-cell activation, while strong affinity of both targeting and effector domains significantly reduces maximum cytokine release. Moreover, by optimizing the affinity of both parts of the molecule, it is possible to improve the selectivity. These results could be effectively modelled based on kinetic proofreading with limited signalling. This model explained the experimental observation that strong binding at both ends of the molecules leads to reduced activity, through very stable target-bispecific-effector complexes leading to CD3 entering a non-signalling dark state. These findings have important implications for the design of anti-CD3-based bispecifics with optimal biophysical parameters for both activity and specificity.

CD6 triggers actomyosin cytoskeleton remodeling after binding to its receptor complex.

The T cell marker CD6 regulates both T cells and target cells during inflammatory responses by interacting with its receptors. However, only a few receptors binding to the extracellular domains of CD6 have been identified, and cellular events induced by CD6 engagement with its receptors in target cells remain poorly understood. In this study, we identified CD44 as a novel CD6 receptor by proximity labeling and confirmed the new CD6-CD44 interaction by biochemical and biophysical approaches. CD44 and the other 2 known CD6 receptors, CD166 and CDCP1, were distributed diffusely on resting retinal pigment epithelium (RPE) cells but clustered together to form a receptor complex upon CD6 binding. CD6 stimulation induced dramatic remodeling of the actomyosin cytoskeleton in RPE cells mediated by activation of RhoA, and Rho-associated kinase signaling, resulting in increased myosin II phosphorylation. Such actomyosin activation triggered the disassembly of tight junctions responsible for RPE barrier integrity in a process that required all components of the tripartite CD6 receptor complex. These data provided new insights into the mechanisms by which CD6 mediates T cell-driven disruption of tissue barriers during inflammation.

Rapid and high throughput assessment of cellular immunity against SARS-CoV-2 based on the ex vivo activation of genes in leukocyte assay with whole blood.

During the novel coronavirus outbreak and vaccine development, antibody production garnered major focus as the primary immunogenic response. However, cellular immunity's recent demonstration of comparable or greater significance in controlling infection demands the re-evaluation of the importance of T-cell immunity in SARS-CoV-2 infection. Here, we developed a novel assay, the ex vivo activation of genes in leukocytes (EAGL), which employs short-term whole blood stimulation with the LeukoComplete™ system, to measure ex vivo SARS-CoV-2-specific T cell responses (cellular immunity). This assay measures upregulated mRNA expression related to leukocyte activation 4 h after antigen stimulation. LeukoComplete™ system uses whole blood samples, eliminating the need for pretreatment before analysis. Furthermore, this system's high reproducibility is ensured through a series of operations from mRNA extraction to cDNA synthesis on a 96-well plate. In the performance evaluation using fresh blood from previously SARS-CoV-2-infected and COVID-19-vaccinated individuals, the EAGL assay had a comparable sensitivity and specificity to the ELISpot assay (EAGL: 1.000/1.000; ELISpot: 0.900/0.973). As a simple, high-throughput assay, the EAGL assay is also a quantitative test that is useful in studies with large sample numbers, such as monitoring new vaccine efficacies against novel coronaviruses or epidemiologic studies that require cellular immune testing during viral infection.