Six-of-the-best: unique contributions of γδ T cells to immunology

Single‑cell RNA‑Seq reveals PBMC profile alterations in a patient following a radiation accident

Nuclear technology has been extensively used in various fields, increasing the possibility of radiation exposure to humans. Radiation exposure outcomes may be classified as whole-body irradiation or local irradiation. Clinically, local irradiation refers to the exposure of a relatively limited portion of the body, with injury confined to the directly exposed tissues. However, locally irradiated tissues can trigger systemic reactions through the release of inflammatory factors or damage to blood cells at the irradiated site. The circulating population of peripheral blood mononuclear cells (PBMCs), a component of normal tissue, is particularly sensitive to ionizing radiation. The present study applied single-cell RNA sequencing (scRNA-Seq) to profile PBMCs from one irradiated patient and 10 healthy controls matched for sex and age. In total, 6,447 and 7,892 cells were collected for analysis from the PBMCs of the irradiated patient on the 113rd and 631st days post radiation, respectively, whereas 9,101 cells were obtained from 10 healthy controls. Following scRNA-Seq, five cell types were annotated via representative markers, revealing distinct cell types whose proportions changed markedly in the irradiated patient. Trajectory analysis indicated that the dysregulation of multiple signaling pathways was associated with radiation exposure. Furthermore, single-cell regulatory network inference and clustering analysis revealed gene regulatory networks and suggested the involvement of several signaling pathways, such as those related to viral infection, in the context of radiation exposure. The present study elucidated the dynamic landscape of human blood immune responses to ionizing radiation and provides evidence of its therapeutic potential for treating radiation injury.

Molecular glue binding behavior of phosphoantigens to alpaca butyrophilins

Vγ9Vδ2 T cells that respond to phosphoantigen (pAgs) function as crucial sentinels of the immune system to eradicate pathogen-infected cells and tumor cells. Alpaca (Vicugna pacos) is the first non-primate species identified to possess the pAg-reactive Vγ9Vδ2 T cell subset. However, the molecular mechanism accounting for the pAgs recognition of alpaca Vγ9Vδ2 T cells remains unclear. Here, we report the crystal structures of alpaca butyrophilin 3 (VpBTN3) B30.2 domain in complex with the exogenous pAg analogue, HMBPP-08, which is a valuable tool for studying the mechanism of BTN-dependent Vγ9Vδ2 T cell activation, and the endogenous pAg analogue, dimethylallyl (S)-thiolodiphosphate (DMASPP). We elucidated that the function of pAgs is governed by their structural differences. Notably, DMASPP acts as a molecular glue in the interaction between the intracellular B30.2 domains of heterologous BTNs in alpaca and human. Interestingly, although HMBPP-08 has stronger affinity than DMASPP to VpBTN3 B30.2 domain, HMBPP-08 did not promote heterologous VpBTNs interaction. These findings establish a novel theoretical framework elucidating the mechanisms of Vγ9Vδ2 T cell activation and demonstrate the conserved evolutionary mechanisms underlying cross-species immune adaptation.

Histone HIST1 genes and tumor-infiltrating lymphocytes in a child with γδ T cell acute lymphoblastic leukemia by single-cell sequencing

γδ T cell acute lymphoblastic leukemia (γδ T-ALL) represents a rare subset of T-ALL and is correlated with high rates of induction failure, relapse, and increased mortality. γδ T-ALL lacks a biologically informed framework for guiding its classification and treatment strategies. In this report, we detail a case of child with γδ T-ALL who underwent induction chemotherapy and intensification treatment, followed by haploidentical hematopoietic stem cell transplantation. The patient achieved a clinical complete remission and remains minimal residual disease negative with chidamide maintenance post-transplantation. Single-cell RNA sequencing revealed a connection between histone HIST1 genes and γδ T-ALL and identified potential effector functions of γδ T cells in combating this leukemia. This case carries significant implications for managing γδ T-ALL, highlighting the relationship between histone modification patterns and γδ tumor-infiltrating lymphocytes in γδ T-ALL cells for developing novel therapeutic approaches.

Immune biomarkers in circulating cells of NSCLC patients can effectively evaluate the efficacy of chemotherapy combined with anti-PD-1 therapy

Introduction

The application of programmed cell death protein 1 (PD-1) antibodies has brought significant benefits to patients with non-small cell lung cancer (NSCLC). However, not all patients respond to PD-1 immune therapy. The aim of this study was to identify response biomarkers to predict the efficacy of chemotherapy combined with anti-PD-1 therapy in NSCLC patients.

Methods

Thirty-two NSCLC patients receiving chemotherapy combined with anti-PD-1 therapy were recruited, and peripheral blood samples were collected before and after treatment. Flow cytometry was used to detect the proportions of circulating T-cell subsets, and cytokines in the blood serum were detected via ELISA.

Results

The results revealed that, among the CR/PR group (CR, complete response; PR, partial response; n = 22), the proportions of CD3+TIM-3+PD-1+, CD3+CD4+TIM-3+PD-1+, and CD3+CD8+TIM-3+PD-1+, CD3+γδT+PD-1+, CD3+γδT+Vδ1+PD-1+, and CD3+γδT+Vδ2+PD-1+T cells were lower after treatment, with no significant differences found between the stable disease (SD) and progressive disease (PD) groups (n = 10). Some proinflammatory cytokines are highly expressed in patients with NSCLC.

Discussion

This study suggests that monitoring changes in immune biomarkers in the circulating cells of NSCLC patients may help differentiate CR/PR patients from SD/PD patients, providing a potential new approach for assessing the efficacy of chemotherapy combined with anti-PD-1 therapy.

γδ T-cell autoresponses to ectopic membrane proteins: a new type of pattern recognition

T-cell receptor (TCR) γδ-expressing cells are conserved lymphocytes of innate immunity involved in first-line defense and immune surveillance. TCRγδ recognizes protein/nonprotein ligands without the help of the major histocompatibility complex (MHC), especially via direct binding to protein ligands, which is dependent primarily on the δ chain complementary determining region 3 (CDR3δ). However, the mechanism of protein‒antigen recognition by human γδ TCRs remains poorly defined. We hypothesize that γδ TCRs recognize self-proteins expressed ectopically on the cell membrane that are derived from intracellular components under stress. Here, we mapped 16 intercellular self-proteins among 21,000 proteins with a huProteinChip as putative ligands for Vδ1/Vδ2 TCRs, 13 for Vδ1 TCRs and 3 for Vδ2 TCRs. Functional tests confirmed that ectopic nucleolin (NCL) is a ligand for the Vδ1 TCR, whereas protein-glutamine γ-glutamyltransferase K (TGM1) is a ligand for the Vδ2 TCR. In the context of radiation exposure, the ectopic expression of intracellular proteins on the tumor cell surface is related to the increased antitumor cytotoxicity of γδ T cells both in vitro and in vivo. In conclusion, the recognition of intracellular proteins that are ectopically expressed on somatic cells by human γδ TCRs is a basic interaction mechanism that enables new types of immune pattern recognition and a novel γδ TCR-ligand-based strategy for tumor immunotherapy.

Engineering innate immune cells for cancer immunotherapy

Innate immune cells, including natural killer cells, macrophages and γδ T cells, are gaining prominence as promising candidates for cancer immunotherapy. Unlike conventional T cells, these cells possess attributes such as inherent antitumor activity, rapid immune responses, favorable safety profiles and the ability to target diverse malignancies without requiring prior antigen sensitization. In this Review, we examine the engineering strategies used to enhance their anticancer potential. We discuss challenges associated with each cell type and summarize insights from preclinical and clinical work. We propose strategies to address existing barriers, providing a perspective on the advancement of innate immune engineering as a powerful modality in anticancer treatment.

Gamma delta T cells and their immunotherapeutic potential in cancer

Gamma-delta (γδ) T cells are a unique subset of T lymphocytes that play diverse roles in immune responses, bridging innate and adaptive immunity. With growing interest in their potential for cancer immunotherapy, a comprehensive and inclusive exploration of γδ T cell families, their development, activation mechanisms, functions, therapeutic implications, and current treatments is essential. This review aims to provide an inclusive and thorough discussion of these topics. Through our discussion, we seek to uncover insights that may harbinger innovative immunotherapeutic strategies. Beginning with an overview of γδ T cell families including Vδ1, Vδ2, and Vδ3, this review highlights their distinct functional properties and contributions to anti-tumor immunity. Despite γδ T cells exhibiting both anti-tumor and pro-tumor activities, our review elucidates strategies to harness the anti-tumor potential of γδ T cells for therapeutic benefit. Moreover, our paper discusses the structural intricacies of the γδ T cell receptor and its significance in tumor recognition. Additionally, this review examines conventional and emerging γδ T cell therapies, encompassing both non-engineered and engineered approaches, with a focus on their efficacy and safety profiles in clinical trials. From multifunctional capabilities to diverse tissue distribution, γδ T cells play a pivotal role in immune regulation and surveillance. By analyzing current research findings, this paper offers insights into the dynamic landscape of γδ T cell-based immunotherapies, underscoring their promise as a potent armamentarium against cancer. Furthermore, by dissecting the complex biology of γδ T cells, we learn valuable information about the anti-cancer contributions of γδ T cells, as well as potential targets for immunotherapeutic interventions.

The clinical landscape of CAR-engineered unconventional T cells

Unconventional T cells, such as invariant natural killer T (iNKT), γδ T, and mucosal-associated invariant T (MAIT) cells, play a pivotal role in bridging innate and adaptive immunity. Their capacity for rapid tumor targeting and effective modulation of the tumor microenvironment (TME) makes them promising candidates for cancer immunotherapy. Advances in chimeric antigen receptor (CAR) engineering have further highlighted their therapeutic potential, particularly for treating challenging cancers. Notably, these cells exhibit favorable safety profiles, enhancing their viability as off-the-shelf therapeutic options. We provide a comprehensive analysis of the clinical applications of CAR-engineered unconventional T cells, focusing on genetic modifications, manufacturing processes, preconditioning regimens, and dosing strategies. We discuss successful examples from recent clinical trials and explore future directions for utilizing these cells in cancer therapy and beyond.

Abnormal glucose and lipid metabolism promotes disrupted differentiation of T and B cell subsets in Behçet's disease

Introduction

Behçet's disease (BD) is a chronic, systemic inflammatory condition characterized by recurrent immune dysregulation.

Materials & Methods

This study conducted a comprehensive analysis of immune cell subsets, metabolic markers, and their interplay in BD patients. Using multiparametric flow cytometry, we identified elevated Th1 cells, senescent CD8+ T cells, and abnormal B cell activation as hallmarks of the chronic inflammatory state in BD.

Results

Despite immunotherapy, innate immune activation persisted, with increased mature NK cells, γδT1 cells, and conventional dendritic cells (cDCs), alongside reduced plasmacytoid dendritic cells (pDCs). Elevated glucose (GLU) and triacylglycerol (TAG) levels in BD patients correlated with increased Th1 cells, functional CD8+ T cells, and B cell activation. In vitro experiments demonstrated that GLU and TAG promote Th1 differentiation, CD8+ T cell activation, and B cell antibody production, revealing their role as drivers of immune dysregulation.

Conclusion

These findings underscore the intricate relationship between metabolic dysregulation and immune dysfunction in BD, highlighting potential diagnostic and therapeutic targets. Our study provides critical insights into BD pathogenesis, offering a foundation for optimizing disease management and monitoring immune and metabolic markers for improved patient outcomes.

γδ T Cells: Game Changers in Immune Cell Therapy for Cancer

Gamma delta (γδ) T cells are a unique subset of T lymphocytes with distinctive features that make them highly promising candidates for cancer therapy. Their MHC-independent recognition of tumor antigens, ability to mediate direct cytotoxicity, and role in modulating the tumor microenvironment position them as versatile agents in cancer immunotherapy. This review integrates and synthesizes the existing data on γδ T cells, with an emphasis on the development and optimization of in vitro expansion protocols. Critical aspects are detailed such as activation strategies, co-culture systems, cytokine use, and other parameters to ensure robust cell proliferation and functionality, which may be valuable for those developing or optimizing clinical practices. Finally, we discuss current advancements in γδ T cell research, clinical experience, and highlight areas needing further exploration. Considering these data, we hypothesize and propose potential new applications such as engineering γδ T cells for enhanced resistance to immune checkpoint pathways or for localized cytokine delivery within the tumor microenvironment, which could broaden their therapeutic impact in the treatment of cancer and beyond.

Diverse Subsets of γδT Cells and Their Specific Functions Across Liver Diseases

γδT cells, a distinct group of T lymphocytes, serve as a link between innate and adaptive immune responses. They are pivotal in the pathogenesis of various liver disorders, such as viral hepatitis, nonalcoholic fatty liver disease (NAFLD), alcoholic liver disease (ALD), liver fibrosis, autoimmune liver diseases, and hepatocellular carcinoma (HCC). Despite their importance, the functional diversity and regulatory mechanisms of γδT cells remain incompletely understood. Recent advances in high-throughput single-cell sequencing and spatial transcriptomics have revealed significant heterogeneity among γδT cell subsets, particularly Vδ1+ and Vδ2+, which exhibit distinct immunological roles. Vδ1+ T cells are mainly tissue-resident and contribute to tumor immunity and chronic inflammation, while Vδ2+ T cells, predominantly found in peripheral blood, play roles in systemic immune surveillance but may undergo dysfunction in chronic liver diseases. Additionally, γδT17 cells exacerbate inflammation in NAFLD and ALD, whereas IFN-γ-secreting γδT cells contribute to antiviral and antifibrotic responses. These discoveries have laid the foundation for the creation of innovative solutions. γδT cell-based immunotherapeutic approaches, such as adoptive cell transfer, immune checkpoint inhibition, and strategies targeting metabolic pathways. Future research should focus on harnessing γδT cells' therapeutic potential through targeted interventions, offering promising prospects for precision immunotherapy in liver diseases.

Characterisation of Cytotoxicity-Related Receptors on γδ T Cells in Chronic Lymphocytic Leukaemia

Chronic lymphocytic leukaemia (CLL) is a haematological malignancy primarily affecting older adults, characterised by the proliferation of functionally impaired B lymphocytes with abnormal expression of CD5, a typical T cell marker. The current study investigates the expression of cytotoxicity-related receptors (CD16, CD56, CD57, CD69) and a checkpoint (LAG-3) on γδ T cells in CLL patients. Sixty-nine treatment-naive CLL patients and fourteen healthy controls were recruited. Flow cytometry analysis revealed that the CLL patients had higher expressions of CD56 and LAG-3 and lower CD16 on their γδ T cells compared to the healthy controls. Subgroup analysis showed that ZAP-70-negative patients exhibited increased CD69, while CD38-negative patients showed higher CD16 expression. Additionally, CD16 expression was inversely correlated with serum LDH levels, a marker of disease progression. Bioinformatic analysis of the LAG-3 ligand mRNA in a CLL dataset indicated higher expression of HLA-DQA2 and HLA-DRB5 in patients with unmutated IGVH. Our findings highlight the altered expression of key cytotoxicity markers on γδ T cells in CLL, suggesting their potential role in disease progression and as a therapeutic target. In particular, the use of anti-LAG-3 antibodies seems promising.

Stereotypic immune response in Mycobacterium avium ssp. paratuberculosis infection among different Swiss caprine genotypes

Paratuberculosis is an infection with Mycobacterium avium ssp. paratuberculosis (MAP) causing chronic enteritis in domestic and wild ruminants worldwide. In goats, the infection is caused by C (cattle)-type and S (sheep)-type strains. In this study, the correlation between different MAP strains and histomorphological lesions in the small and large intestines, as well as the mesenteric lymph nodes, in Swiss goats (Caprae aegagrus hircus) was investigated. Ten Swiss caprine MAP isolates were characterized using polymerase chain reaction (PCR) and enzymatic restriction-based single nucleotide polymorphism (SNP) analysis. In addition, mycobacterial interspersed repetitive units and variable-number tandem repeats (MIRU-VNTR) profiling was performed, and the correlation with histologic lesions, scored as previously described for goats, was analyzed. Furthermore, immunohistochemical expression of CD3, CD79a, Iba1, cleaved caspase 3, and interleukin (IL)-17 was evaluated, and a morphometric analysis was conducted to quantify the different inflammatory cells. Diffuse multibacillary lesions were found in C-type/L'Institut national de recherche pour l'agriculture, l'alimentation et l'environnement (INRAE) Nouzilly MIRU-VNTR (INMV)1 (2/10) and S-type/INMV220 (1/10) animals. Diffuse lymphocytic lesions occurred in C-type/INMV1 (2/10) animals, while diffuse mixed lesions were observed in S-type/INMV218 (3/10) and S-type/INMV220 (2/10) animals. No significant differences in intestinal histological lesion scores were detected between S- and C-type INMV strains. Morphometrical analysis revealed similar inflammatory and apoptotic cell numbers in the intestinal mucosa of C- and S-type animals; however, S-type animals exhibited significantly more Iba1- and cleaved caspase 3-positive cells in mesenteric lymph nodes. Lesions in mesenteric lymph nodes might indicate a differentially regulated course in MAP pathogenesis.

Dynamic STING repression orchestrates immune cell development and function

STING is an essential component of the innate immune system, yet homeostatic STING expression patterns and regulation are unknown. Using Sting1IRES-EGFP reporter and conditional Sting1 transgenic mice, we found that regulation of STING expression is critical for immune cell development and functionality. STING expression was repressed in neutrophils, and forced STING expression or signaling drove systemic inflammatory disease. During T lymphocyte development, STING expression was restricted at the double-positive stage via epigenetic silencing by DNA methyltransferase 1. Forced STING expression or signaling impaired T lymphocyte development independent of type I interferon and promoted lineage commitment to innate-like γδ T cells over adaptive αβ T cells. In the tumor microenvironment, CD8+ T lymphocytes repressed STING expression, correlating with features of T cell exhaustion in syngeneic mouse tumors and human colorectal cancer. Our data demonstrate the necessity of controlled, rather than ubiquitous, STING expression, uncovering a previously unappreciated dimension of STING pathobiology.

Exploring the immuno-nano nexus: A paradigm shift in tumor vaccines

Tumor vaccines have become a crucial strategy in cancer immunotherapy. Challenges of traditional tumor vaccines include inadequate immune activation and low efficacy of antigen delivery. Nanoparticles, with their tunable properties and versatile functionalities, have redefined the landscape of tumor vaccine design. In this review, we outline the multifaceted roles of nanoparticles in tumor vaccines, ranging from their capacity as delivery vehicles to their function as immunomodulatory adjuvants capable of stimulating anti-tumor immunity. We discuss how this innovative approach significantly boosts antigen presentation by leveraging tailored nanoparticles that facilitate efficient uptake by antigen-presenting cells. These nanoparticles have been meticulously designed to overcome biological barriers, ensuring optimal delivery to lymph nodes and effective interaction with the immune system. Overall, this review highlights the transformative power of nanotechnology in redefining the principles of tumor vaccines. The intent is to inform more efficacious and precise cancer immunotherapies. The integration of these advanced nanotechnological strategies should unlock new frontiers in tumor vaccine development, enhancing their potential to elicit robust and durable anti-tumor immunity.

Characterizing Nodal Gamma-Delta T-Cell Lymphoma: Clinicopathological and Molecular Insights

Peripheral T-cell lymphomas with gamma-delta phenotype (GDTCL) are rare lymphoid malignancies. Beyond the well-recognized entities of extranodal lymphomas with gamma-delta phenotype as defined by the fifth edition of the World Health Organization Classification of Hematolymphoid Tumors and 2022 International Consensus Classification, there is a group of poorly defined gamma-delta T-cell lymphomas with predominantly nodal presentation, termed as nodal GDTCL (nGDTCL). In this study, we present a series of 12 cases of Epstein-Barr virus-negative nGDTCL, highlighting the clinical, histopathological, and molecular features of this rare entity. Seven cases reported in the literature were included in the analysis. Of the 12 cases, nGDTCL shows an increased incidence in elderly men, with a median age of 65.5 years. All cases presented primarily with enlarged lymph nodes, and 4 cases (4/12, 33.3%) showed involvement of extranodal sites, including skin, liver, spleen, and bone marrow. Histologically, 9 cases showed a diffuse and monomorphic proliferation of mostly medium-to-large lymphoid cells, whereas 3 cases demonstrated lymphoepithelioid morphology. All cases (12/12, 100%) were positive for CD3 and TCRγδ. CD4, CD8, and CD56 were positive in 66.7% (8/12), 25% (3/12), and 8.3% (1/11) of cases, respectively. Most cases (8/12, 66.7%) showed a noncytotoxic phenotype. Using immunohistochemistry, the majority of cases (6/8, 75.0%) belonged to the peripheral T-cell lymphoma-GATA3 subtype with GATA3 and/or CCR4 expression and a noncytotoxic CD4-positive phenotype. Two cases (2/8, 25%) belonged to the peripheral T-cell lymphoma-TBX21 subtype, of which 1 displayed a cytotoxic CD8-positive phenotype. Next-generation sequencing was performed in 9 cases, and TP53 mutation was detected in 66.7% (6/9) of the cases. Mutations of ATM and KSR2 were identified in 2 cases each. It remains uncertain whether nGDTCL represents a distinct entity, and further studies are needed for better characterization. Nonetheless, nodal-based GDTCL should be distinguished from secondary nodal involvement by other extranodal GDTCL and Epstein-Barr virus-positive T/NK-cell lymphoproliferative diseases.

Infiltration and subtype analysis of CD3 + CD20 + T cells in lung cancer

BACKGROUND

CD3 + CD20 + T cells (TB cells) are a subset of lymphocytes in the human body that are associated with inflammation. They originate from T cells interacting with B cells, and their levels are abnormally elevated in individuals with immune disorders, as well as in some cancer patients. The interplay between tumor immunity and inflammation is intricate, yet the specific involvement of TB cells in local tumor immunity remains uncertain, with limited research on their subtypes.

METHODS

Lung cancer surgical samples were stained using multi-color immunofluorescence to study the subtypes and distribution patterns of TB cells.

RESULTS

TB cells were confirmed to exist in a scattered pattern within tertiary lymphoid structures (TLS) in lung cancer tissues, with higher abundance in mature TLS. In subtype analysis, the CD4-CD8- double-negative TB cell subtype was predominant, comprising over 90% in samples with abundant TLS infiltration and over 60% in samples with poor infiltration. This was followed by the CD4 + CD8- and CD4-CD8 + single-positive TB cell subtypes, while the CD4 + CD8 + double-positive TB cell subtype was nearly absent. During the maturation of TLS, the proportion of B cells gradually increased, while the proportion of CD4-CD8- T cell subtype decreased.

CONCLUSIONS

TB cells extensively infiltrate the TLS regions in tumor tissues, with the double-negative subtype being predominant, potentially playing a crucial regulatory role in the local tumor immune microenvironment. This finding could facilitate the advancement of novel cancer treatment strategies.

Hyperglycemic milieu impairs Vγ9Vδ2 T cell functions in tuberculosis patients and prolongs M.tb negative conversion time

γδ T cells play protective roles in tuberculosis (TB). Our work demonstrated the therapeutic potential of allogeneic Vγ9Vδ2 T cells in TB patients. However, their functions in TB require further comprehensive evaluation. Here, we compared γδ T cells in TB patients and healthy adults at the bulk and single-cell RNA and protein levels, revealing that impaired glucose metabolism critically undermines their anti-infective functions. Excessive glucose disrupts γδ T cell effector functions, correlating with prolonged sputum smear conversion time in TB patients with type II diabetes. Additionally, serum glucose levels were linked to multidrug-resistant TB. These findings suggest that weakened Vδ2+γδ T cell responses in diabetic TB patients contribute to multidrug resistance. Restoring Vδ2+γδ T cell function offers a promising strategy for TB treatment.

Biophysical and Structural Features of αβT-Cell Receptor Mechanosensing: A Paradigmatic Shift in Understanding T-Cell Activation

αβT cells protect vertebrates against many diseases, optimizing surveillance using mechanical force to distinguish between pathophysiologic cellular alterations and normal self-constituents. The multi-subunit αβT-cell receptor (TCR) operates outside of thermal equilibrium, harvesting energy via physical forces generated by T-cell motility and actin-myosin machinery. When a peptide-bound major histocompatibility complex molecule (pMHC) on an antigen presenting cell is ligated, the αβTCR on the T cell leverages force to form a catch bond, prolonging bond lifetime, and enhancing antigen discrimination. Under load, the αβTCR undergoes reversible structural transitions involving partial unfolding of its clonotypic immunoglobulin-like (Ig) domains and coupled rearrangements of associated CD3 subunits and structural elements. We postulate that transitions provide critical energy to initiate the signaling cascade via induction of αβTCR quaternary structural rearrangements, associated membrane perturbations, exposure of CD3 ITAMs to phosphorylation by non-receptor tyrosine kinases, and phase separation of signaling molecules. Understanding force-mediated signaling by the αβTCR clarifies long-standing questions regarding αβTCR antigen recognition, specificity and affinity, providing a basis for continued investigation. Future directions include examining atomistic mechanisms of αβTCR signal initiation, performance quality, tissue compliance adaptability, and T-cell memory fate. The mechanotransduction paradigm will foster improved rational design of T-cell based vaccines, CAR-Ts, and adoptive therapies.

Vγ6/Vδ1 + γδ T cells protect from angiotensin II effects on blood pressure and endothelial function in mice

OBJECTIVES

γδ T cells mediate angiotensin II (AngII)-induced hypertension and vascular injury. γδ T cells expressing specific T-cell receptor (TCR) variable (V) γ chains develop in several waves in the thymus and migrate to specific or diverse tissues. We hypothesized that γδ T cells expressing specific Vγ subtypes in perivascular tissue mediate AngII hypertensive effects.

METHODS

C57BL/6J male mice were infused or not with AngII (490 ng/kg/min, subcutaneously) for 14 days. γδ T-cell Vγ subtypes were profiled by flow cytometry in the spleen, descending thoracic aorta with adherent perivascular adipose tissue (DTAo/PVAT) and mesenteric vessels (MV)/PVAT. Other sets of AngII-infused mice were injected with control or specific anti-Vγ6 or Vγ4 antibodies. Blood pressure (BP) was determined by telemetry, and mesenteric artery function and remodeling by pressurized myography.

RESULTS

Vγ6/Vδ1 + γδ T cells represented more than 50% of the γδ T-cell Vγ subtypes in DTAo/PVAT and MV/PVAT, whereas Vγ1/2 + , Vγ4 + and Vγ6/Vδ1 + γδ T cells were the most abundant Vγ subtypes in the spleen. The frequency of Vγ6/Vδ1 + γδ T cells was increased at least 1.5-fold in the spleen and DTAo/PVAT, and tended to increase in MV/PVAT by AngII. A majority of Vγ6/Vδ1 + γδ T cells were activated in perivascular tissues. Vγ6/Vδ1 + γδ T-cell neutralization caused a steeper BP elevation and greater mesenteric artery endothelial dysfunction in mice infused with AngII. This was associated with more than three-fold increase in activated Vγ6/Vδ1 - γδ T cells in perivascular tissues. Depletion of Vγ4 + γδ T cells did not alter AngII detrimental effects.

CONCLUSION

Vγ6/Vδ1 + γδ T cells reduce the BP elevation and endothelial dysfunction induced by AngII infusion.

Immune Microenvironment in Breast Cancer Metastasis

Metastatic disease is the final stage of breast cancer that accounts for vast majority of patient death. Mounting data over recent years strongly support the critical roles of the immune microenvironment in determining breast cancer metastasis. The latest single-cell studies provide further molecular evidence illustrating the heterogeneity of this immune microenvironment. This chapter summarizes major discoveries on the role of various immune cells in metastasis progression and discusses future research opportunities. Studies investigating immune heterogeneity within primary breast cancer and across different metastasis target organs can potentially lead to more precise treatment strategies with improved efficacy.

Immunological characterization of pleural effusions in pediatric patients

Background

The pleural cavity represents a unique immunological compartment that can mount inflammatory reactions during infections, after surgery and in chronic immunological diseases. The connection between systemic immune reactions in the blood and local immune reactions in pleural effusions remains unclear. This study provides the first comprehensive immunological characterization of paired blood and pleural effusion samples, utilizing combined cell and cytokine analyses in pediatric patients undergoing cardiac surgery.

Methods

In 30 pediatric patients (median age: 22 months) with pleural effusion after cardiac surgery for congenital heart defects, corresponding peripheral blood and pleural effusion samples were analyzed for their immune response. We used flow cytometry and multiplex immunoassays to quantify 14 T cell subpopulations and 12 T cell associated cytokines in each biosample.

Results

IL-6, IL-8, IL-10, TNF (p<0.0001) levels were significantly higher in pleural effusion compared to plasma. In contrast, IFN-γ, GM-CSF, IL-17A levels were lower in pleural effusion than in plasma (p ≤ 0.0005). In comparison to peripheral blood, there was a significantly higher proportion of T helper cells 1 (Th1, p=0.0023), T helper cells 17 (Th17, p=0.0334) and memory effector cytotoxic T cells (CD3+CD8+CD45RO+CD62L-, p=0.0449) in pleural effusion and the same trend was observed for memory effector Th cells (CD3+CD4+CD45RO+CD62L-, p=0.0633) and double-negative T cells (CD3+CD4-CD8-) (p=0.1085). Naïve Th cells (CD3+CD4+CD45RO-CD62L+) and naïve cytotoxic T cells (CD3+CD8+CD45RO-CD62L+) were slightly reduced in pleural effusion compared to peripheral blood (not significant).

Conclusion

Immunological factors in pleural effusions differed significantly from the corresponding blood samples in pediatric patients after cardiac surgery. The results suggest localized production of specific cytokines within the pleural space, while the distribution of other cytokines in pleural effusions appears to be more reflective of the systemic immune response. We found evidence that on the cellular level, the surface marker CD62L may play a key role in navigating T cells between the blood and pleural effusion. This study confirms that the pleural cavity harbors a unique lymphatic compartment, the analysis of which may be useful for both diagnostic and therapeutic purposes.

Circulating T cells in sarcoidosis have an aberrantly activated phenotype that correlates with disease outcome

RATIONALE

Disease course in sarcoidosis is highly variable. Bronchoalveolar lavage fluid and mediastinal lymph nodes show accumulation of activated T cells with a T-helper (Th)17.1 signature, which correlates with non-resolving sarcoidosis. We hypothesize that the peripheral blood (PB) T cell phenotype may correlate with outcome.

OBJECTIVES

To compare frequencies, phenotypes and function of circulating T cell populations in sarcoidosis patients with healthy controls (HCs) and correlate these parameters with outcome.

METHODS

We used multi-color flow cytometry to quantify activation marker expression on PB T cell subsets in treatment-naïve patients and HCs. The disease course was determined after 2-year follow-up. Cytokine production was measured after T cell stimulation in vitro.

MEASUREMENTS AND MAIN RESULTS

We observed significant differences between patients and HCs in several T cell populations, including CD8+ and CD4+ T cells, Th1/Th17 subsets, CD4+ T memory stem cells, regulatory T cells (Tregs) and γδ T cells. Decreased frequencies of CD4+ T cells and increased frequencies of Tregs and CD8+ γδ T cells correlated with worse outcome. Naïve CD4+ T cells displayed an activated phenotype with increased CD25 expression in patients with active chronic disease at 2-year follow-up. A distinctive Treg phenotype with increased expression of CD25, CTLA4, CD69, PD-1 and CD95 correlated with chronic sarcoidosis. Upon stimulation, both naïve and memory T cells displayed a different cytokine profile in sarcoidosis compared to HCs.

CONCLUSIONS

Circulating T cell subpopulations of sarcoidosis patients display phenotypic abnormalities that correlate with disease outcome, supporting a critical role of aberrant T cell activation in sarcoidosis pathogenesis.

Lymphocytes and innate immune cells in acute kidney injury and repair

Acute kidney injury (AKI) is a common and serious disease entity that affects native kidneys and allografts but for which no specific treatments exist. Complex intrarenal inflammatory processes driven by lymphocytes and innate immune cells have key roles in the development and progression of AKI. Many studies have focused on prevention of early injury in AKI. However, most patients with AKI present after injury is already established. Increasing research is therefore focusing on mechanisms of renal repair following AKI and prevention of progression from AKI to chronic kidney disease. CD4+ and CD8+ T cells, B cells and neutrophils are probably involved in the development and progression of AKI, whereas regulatory T cells, double-negative T cells and type 2 innate lymphoid cells have protective roles. Several immune cells, such as macrophages and natural killer T cells, can have both deleterious and protective effects, depending on their subtype and/or the stage of AKI. The immune system not only participates in injury and repair processes during AKI but also has a role in mediating AKI-induced distant organ dysfunction. Targeted manipulation of immune cells is a promising therapeutic strategy to improve AKI outcomes.

Advances in Understanding of the Role of Immune Cell Phenotypes in Hypertension and Associated Vascular Disease

Many studies in the past 20 years have identified a contribution of inflammation and immune mechanisms to the pathophysiology of hypertension. Innate and adaptive immunity participate in this process. Among innate immune cells, macrophages and monocytes as well as dendritic cells, myeloid-derived suppressor cells, and neutrophils directly or via formation of neutrophil extracellular traps, play roles in the modulation of the inflammatory response in hypertension. Among adaptive immune cells, T and B cells have been implicated to varying degrees, particularly interleukin (IL)-17- and interferon γ-producing T lymphocytes, antagonized by T regulatory lymphocytes that are anti-inflammatory via production of IL-10. Among T cells that produce abundant IL-17, γδ T cells are unconventional T lymphocytes that are infrequent in the circulation in contrast to the much more abundant circulating αβ T lymphocytes, but are found mostly in tissues, and appear to play a role in triggering and sustaining inflammation in hypertension leading to vascular and renal injury. This review will provide an overview of these different immune cell phenotypes involved in the immune pathophysiology of hypertension and associated vascular disease.

Systematic analysis of human colorectal cancer scRNA-seq revealed limited pro-tumoral IL-17 production potential in gamma delta T cells

Gamma delta T cells play a crucial role in anti-tumor immunity due to their cytotoxic properties. However, the role and extent of γδ T cells in production of pro-tumorigenic interleukin-17 (IL-17) within the tumor microenvironment of colorectal cancer (CRC) remains controversial. In this study, we re-analyzed nine published human CRC whole-tissue single-cell RNA sequencing datasets, identifying 18,483 γδ T cells out of 951,785 total cells, in the neoplastic or adjacent normal tissue of 165 human CRC patients. Our results confirm that tumor-infiltrating γδ T cells exhibit high cytotoxicity-related transcription in both tumor and adjacent normal tissues, but critically, none of the γδ T cell clusters showed IL-17 production potential. We also identified various γδ T cell subsets, including poised effector-like T cells, tissue-resident memory T cells, progenitor exhausted-like T cells, and exhausted T cells, and noted an increased expression of cytotoxic molecules in tumor-infiltrating γδ T cells compared to their normal area counterparts. We proposed anti-tumor γδ T effector cells may arise from tissue-resident progenitor cells based on the trajectory analysis. Our work demonstrates that γδ T cells in CRC primarily function as cytotoxic effector cells rather than IL-17 producers, mitigating the concerns about their potential pro-tumorigenic roles in CRC, highlighting the importance of accurately characterizing these cells for cancer immunotherapy research and the unneglectable cross-species discrepancy between the mouse and human immune system in the study of cancer immunology.

Validation of analytical methods for the production of expanded γδ T lymphocytes useful for therapeutic purposes

The use of γδ T lymphocytes as advanced therapeutic medicinal product has attracted much interest in the last years. Indeed, such cells are an ideal tool for the reconstitution of the immune system in patients receiving hematopoietic stem cell transplantation, due to their MHC-independent anti-tumor and anti-viral activities. We have here setup a protocol for the production of pure and functional γδ T lymphocytes, expanded from healthy donors' mononuclear cells, and validated the analytical methods to identify them and to analyze their potency. Next, we performed stability studies to ensure that the cell product (γδ T cells) can be used after freezing and thawing. Notably, such protocol can be promptly translated to GMP-facility, since it has been designed using only clinical grade reagents.

Skin-Resident γδ T Cells Mediate Potent and Selective Antitumor Cytotoxicity through Directed Chemotactic Migration and Mobilization of Cytotoxic Granules

Dendritic epidermal T cells (DETCs) are a unique subset of γδ T cells that reside predominantly in mouse epidermis; yet, their antitumor functions remain enigmatic. In this study, we report that DETCs mediate potent and exquisitely selective cytotoxicity against diverse tumor types while sparing healthy cells. In vitro, DETCs induced apoptosis in melanoma, hepatoma, colon carcinoma, and lymphoma lines in a dose- and time-dependent manner that required direct cell-cell contact. In vivo, adoptive DETC transfer significantly suppressed melanoma growth and metastasis while prolonging survival. Mechanistically, DETCs upregulated perforin/granzyme B expression upon tumor recognition, and inhibition of this pathway ablated cytotoxicity. DETCs selectively homed to and formed intimate contacts with tumor cells in vivo through directed chemotaxis and aggregation. Tumor engagement triggered proinflammatory DETC activation while dampening immunosuppressive factors in the microenvironment. Notably, mTOR signaling coupled tumor recognition to DETC trafficking, cytotoxicity, and inflammatory programs because rapamycin treatment impaired effector functions and therapeutic efficacy. Collectively, these findings establish DETCs as multidimensional antitumor effectors and provide insights for harnessing their unique biology for cancer immunotherapy.

Genetically predicted blood metabolites mediate the association between circulating immune cells and severe COVID-19: A Mendelian randomization study

Investigating the causal relationship between circulating immune cells, blood metabolites, and severe COVID-19 and revealing the role of blood metabolite-mediated circulating immune cells in disease onset and progression. Genetic variation data of 731 circulating immune cells, 1400 blood metabolites, and severe COVID-19 from genome-wide association study open-access database (https://gwas.mrcieu.ac.uk) were used as instrumental variables for bidirectional and two-step Mendelian randomization analysis. The study identified 11 circulating immune cells with unidirectional causality to severe COVID-19. Two-step Mendelian randomization analysis showed 10 blood metabolites were causally associated with severe COVID-19, and blood Myristate and Citrulline to phosphate ratio mediated the association of circulating effector memory double negative % DN and CD8dim natural killer T cell % T cells, respectively, with severe COVID-19 (Myristate mediated effect ratio was 10.20%, P = .011; Citrulline to phosphate ratio mediated effect ratio was -9.21%, P = .017). This study provides genetic evidence assessing the causal relationship between circulating immune cells, blood metabolites, and severe COVID-19, elucidates the role of blood metabolite-mediated circulating immune cells in severe COVID-19 development, and offers new insights into severe COVID-19 etiology and related preventive and targeted therapeutic strategies.

Specific selection of stimulation-responsive γδ T-cells utilizing a short-term activation assay

T cells expressing the γδ T-cell receptor (TCR) represent a numerically small proportion of total T cells. Unlike αβ T cells they are activated by non-peptide antigens independently of MHC-presentation. γδ T cells have been recognized as a favorable prognostic marker across different tumor entities. Recently, γδ T cells (in particular Vδ2 T cells), have gained attention because of their effective intrinsic anti-tumor reactivity. Moreover, their ability for MHC-independent activation and in vitro expansion to high numbers makes them attractive candidates for tumor immunotherapy by adoptive transfer. In this regard, the ex vitro identification of highly reactive γδ T cells upon stimulation enables us to specifically identify, isolate and expand γδ T cells which potentially represent those with high anti-tumor reactivity. CD137 and CD154 represent suitable markers for identifying specifically activated γδ T cells. In humans, the surface mobilization of CD137 and CD154 reveals antigen-specific activation of regulatory (Treg) and conventional CD4 T cells, respectively. We adapted this method for the analysis of Vδ2 T cells, in which the mobilization of both CD137 and CD154 can be used to investigate their activation, whereby CD137 and CD154 do not discriminate regulatory from conventional cells. Thus, this method provides a new way to rapidly analyze quick changes in Vδ2 T-cell activation and allows for using these markers for cell sorting and subsequent expansion of the specifically reacting Vδ2 T cells.

Investigating potential drug targets for IgA nephropathy and membranous nephropathy through multi-queue plasma protein analysis: a Mendelian randomization study based on SMR and co-localization analysis

BACKGROUND

Membranous nephropathy (MN) and IgA nephropathy (IgAN) pose challenges in clinical treatment with existing therapies primarily focusing on symptom relief and often yielding unsatisfactory outcomes. The search for novel drug targets remains crucial to address the shortcomings in managing both kidney diseases.

METHODS

Utilizing GWAS data for MN (ncase = 2150, ncontrol = 5829) and IgAN (ncase = 15587, ncontrol = 462197), instrumental variables for plasma proteins were derived from recent GWAS. Sensitivity analysis involved bidirectional Mendelian randomization analysis, MR Steiger, Bayesian co-localization, and Phenotype scanning. The SMR analysis using eQTL data from the eQTLGen Consortium was conducted to assess the availability of selected protein targets. The PPI network was constructed to reveal potential associations with existing drug treatment targets.

RESULTS

The study, subjected to the stringent Bonferroni correction, revealed significant associations: four proteins with MN and three proteins with IgAN. In plasma protein cis-pQTL data from two cohorts, an increase in one standard deviation in PLA2R1 (OR = 2.01, 95%CI = 1.83-2.21), AIF1 (OR = 9.04, 95%CI = 4.69-17.41), MLN (OR = 3.79, 95%CI = 2.12-6.78), and NFKB1 (OR = 29.43, 95%CI = 7.73-112.0) was associated with an increased risk of MN. Additionally, in plasma protein cis-pQTL data, a standard deviation increase in FCGR3B (OR = 1.15, 95%CI = 1.09-1.22) and BTN3A1 (OR = 4.05, 95%CI = 2.65-6.19) correlated with elevated IgAN risk, while AIF1 (OR = 0.58, 95%CI = 0.46-0.73) exhibited IgAN protection. Bayesian co-localization indicated that PLA2R1 (coloc.abf-PPH4 = 0.695), NFKB1 (coloc.abf-PPH4 = 0.949), FCGR3B (coloc.abf-PPH4 = 0.909), and BTN3A1 (coloc.abf-PPH4 = 0.685) share the same variants associated with MN and IgAN. The SMR analysis indicated a causal link between NFKB1 and BTN3A1 plasma protein eQTL in both conditions, and BTN3A1 was validated externally.

CONCLUSION

Genetically influenced plasma levels of PLA2R1 and NFKB1 impact MN risk, while FCGR3B and BTN3A1 levels are causally linked to IgAN risk, suggesting potential drug targets for further clinical exploration, notably BTN3A1 for IgAN.

Dendritic/antigen presenting cell mediated provision of T-cell receptor gamma delta (TCRγδ) expressing cells contributes to improving antileukemic reactions ex vivo

T-cell receptor gamma delta (TCRγδ) expressing T-cells are known to mediate an MHC-independent immune response and could therefore qualify for immune therapies. We examined the influence of dendritic cells(DC)/antigen presenting cell (APC) generated from blast-containing whole blood (WB) samples from AML and MDS patients on the provision of (leukemia-specific) TCRγδ expressing T-cells after mixed lymphocyte culture (MLC). Kit-M (granulocyte-macrophage colony-stimulating factor (GM-CSF) + prostaglandin E1 (PGE1)) or Kit-I (GM-CSF + Picibanil) were used to generate leukemia derived APC/DC (DCleu)from WB, which were subsequently used to stimulate T-cell enriched MLC. Immune cell composition and functionality were analysed using degranulation- (DEG), intracellular cytokine- (INTCYT) and cytotoxicity fluorolysis- (CTX) assays. Flow cytometry was used for cell quantification. We found increased frequencies of APCs/DCs and their subtypes after Kit-treatment of healthy and patients´ WB compared to control, as well as an increased stimulation and activation of several types of immune reactive cells after MLC. Higher frequencies of TCRγδ expressing leukemia-specific degranulation and intracellularly cytokine producing T-cells were found. The effect of Kit-M-treatment on frequencies of TCRγδ expressing cells and their degranulation could be correlated with the Kit-M-mediated blast lysis compared to control. We also found higher frequencies of TCRγδ expressing T-cells in AML patients´ samples with an achieved remission (compared to blast persistence) after induction chemotherapy. This might point to APC/DC-mediated effects resulting in the provision of leukemia-specific TCRγδ expressing T-cells: Moreover a quantification of TCRγδ expressing T-cells might contribute to predict prognosis of AML/MDS patients.

Unlocking the therapeutic potential of the NKG2A-HLA-E immune checkpoint pathway in T cells and NK cells for cancer immunotherapy

Immune checkpoint blockade, which enhances the reactivity of T cells to eliminate cancer cells, has emerged as a potent strategy in cancer therapy. Besides T cells, natural killer (NK) cells also play an indispensable role in tumor surveillance and destruction. NK Group 2 family of receptor A (NKG2A), an emerging co-inhibitory immune checkpoint expressed on both NK cells and T cells, mediates inhibitory signal via interaction with its ligand human leukocyte antigen-E (HLA-E), thereby attenuating the effector and cytotoxic functions of NK cells and T cells. Developing antibodies to block NKG2A, holds promise in restoring the antitumor cytotoxicity of NK cells and T cells. In this review, we delve into the expression and functional significance of NKG2A and HLA-E, elucidating how the NKG2A-HLA-E axis contributes to tumor immune escape via signal transduction mechanisms. Furthermore, we provide an overview of clinical trials investigating NKG2A blockade, either as monotherapy or in combination with other therapeutic antibodies, highlighting the responses of the immune system and the clinical benefits for patients. We pay special attention to additional immune co-signaling molecules that serve as potential targets on both NK cells and T cells, aiming to evoke more robust immune responses against cancer. This review offers an in-depth exploration of the NKG2A-HLA-E pathway as a pivotal checkpoint in the anti-tumor responses, paving the way for new immunotherapeutic strategies to improve cancer patient outcomes.

Restriction of innate Tγδ17 cell plasticity by an AP-1 regulatory axis

IL-17-producing γδ T (Tγδ17) cells are innate-like mediators of intestinal barrier immunity. While Th17 cell and ILC3 plasticity have been extensively studied, the mechanisms governing Tγδ17 cell effector flexibility remain undefined. Here, we combined type 3 fate-mapping with single cell ATAC/RNA-seq multiome profiling to define the cellular features and regulatory networks underlying Tγδ17 cell plasticity. During homeostasis, Tγδ17 cell effector identity was stable across tissues, including for intestinal T-bet+ Tγδ17 cells that restrained IFNγ production. However, S. typhimurium infection induced intestinal Vγ6+ Tγδ17 cell conversion into type 1 effectors, with loss of IL-17A production and partial RORγt downregulation. Multiome analysis revealed a trajectory along Vγ6+ Tγδ17 effector conversion, with TIM-3 marking ex-Tγδ17 cells with enhanced type 1 functionality. Lastly, we characterized and validated a critical AP-1 regulatory axis centered around JunB and Fosl2 that controls Vγ6+ Tγδ17 cell plasticity by stabilizing type 3 identity and restricting type 1 effector conversion.

Pan-cancer γδ TCR analysis uncovers clonotype diversity and prognostic potential

Gamma-delta T cells (γδ T cells) play a crucial role in both innate and adaptive immunity within tumors, yet their presence and prognostic value in cancer remain underexplored. This study presents a large-scale analysis of γδ T cell receptor (γδ TCR) reads from 11,000 tumor samples spanning 33 cancer types, utilizing the TRUST4 algorithm. Our findings reveal extensive diversity in γδ TCR clonality and gene expression, underscoring the potential of γδ T cells as prognostic biomarkers in various cancers. We further demonstrate the utility of TCR gamma (TRG) and delta (TRD) gene expression from standard RNA-sequencing (RNA-seq) data. This comprehensive dataset offers a valuable resource for advancing γδ T cell research, with implications for enhanced immunotherapy approaches or alternative therapeutic strategies. Additionally, our centralized database supports translational research into the therapeutic significance of γδ T cells.

Generation of ex vivo autologous hematopoietic stem cell-derived T lymphocytes for cancer immunotherapy

CD19CAR-T cell therapy demonstrated promising outcomes in relapsed/refractory B-cell malignancies. Nonetheless, the limited T-cell function and ineffective T-cell apheresis for therapeutic purposes are still concern in heavily pretreated patients. We investigated the feasibility of generating hematopoietic stem cell-derived T lymphocytes (HSC-T) for cancer immunotherapy. The patients' autologous peripheral blood HSCs were enriched for CD34+ and CD3+ cells. The CD34+ cells were then cultured following three steps of lymphoid progenitor differentiation, T-cell differentiation, and T-cell maturation processes. HSC-T cells were successfully generated with robust fold expansion of 3735 times. After lymphoid progenitor differentiation, CD5+ and CD7+ cells remarkably increased (65-84 %) while CD34+ cells consequentially declined. The mature CD3+ cells were detected up to 40 % and 90 % on days 42 and 52, respectively. The majority of HSC-T population was naïve phenotype compared to CD3-T cells (73 % vs 34 %) and CD8:CD4 ratio was 2:1. The higher level of cytokine and cytotoxic granule secretion in HSC-T was observed after activation. HSC-T cells were assessed for clinical application and found that CD19CAR-transduced HSC-T cells demonstrated higher cytokine secretion and a trend of superior cytotoxicity against CD19+ target cells compared to control CAR-T cells. A chronic antigen stimulation assay revealed similar T-cell proliferation, stemness, and exhaustion phenotypes among CAR-T cell types. In conclusions, autologous HSC-T was feasible to generate with preserved T-cell efficacy. The HSC-T cells are potentially utilized as an alternative option for cellular immunotherapy.

Synthesis and evaluation of (E)-4-hydroxy-3-methyl-but-2-enyl diphosphate analogs as competitive partial agonists of butyrophilin 3A1

Phosphoantigens (pAgs) induce conformational changes after binding to the intracellular region of BTN3A1 which result in its clustering with BTN2A1, forming an activating ligand for the Vγ9Vδ2 T cell receptor. Here, we designed a small panel of bulky analogs of the prototypical pAg (E)-4-hydroxy-3-methyl-but-2-enyl diphosphate (HMBPP) that contain an aromatic ring attached to the C-3 position in place of methyl group. These compounds bind with high affinity to BTN3A1 but fail to fully support its interaction with BTN2A1 and only partially trigger T cell activation relative to HMBPP. Furthermore, they can compete with HMBPP for cellular binding to BTN3A1 and reduce the cellular response to HMBPP, a classic partial agonist phenotype. Trifluoromethyl analog 6e was the weakest agonist but the strongest inhibitor of HMBPP ELISA response. Our study provides a rationale for the mode of action of pAg-induced γδ T cell activation and provides insights into other naturally occurring BTN proteins and their respective ligands.

Interplay between pulmonary epithelial stem cells and innate immune cells contribute to the repair and regeneration of ALI/ARDS

Mammalian lung is the important organ for ventilation and exchange of air and blood. Fresh air and venous blood are constantly delivered through the airway and vascular tree to the alveolus. Based on this, the airways and alveolis are persistently exposed to the external environment and are easily suffered from toxins, irritants and pathogens. For example, acute lung injury/acute respiratory distress syndrome (ALI/ARDS) is a common cause of respiratory failure in critical patients, whose typical pathological characters are diffuse epithelial and endothelial damage resulting in excessive accumulation of inflammatory fluid in the alveolar cavity. The supportive treatment is the main current treatment for ALI/ARDS with the lack of targeted effective treatment strategies. However, ALI/ARDS needs more targeted treatment measures. Therefore, it is extremely urgent to understand the cellular and molecular mechanisms that maintain alveolar epithelial barrier and airway integrity. Previous researches have shown that the lung epithelial cells with tissue stem cell function have the ability to repair and regenerate after injury. Also, it is able to regulate the phenotype and function of innate immune cells involving in regeneration of tissue repair. Meanwhile, we emphasize that interaction between the lung epithelial cells and innate immune cells is more supportive to repair and regenerate in the lung epithelium following acute lung injury. We reviewed the recent advances in injury and repair of lung epithelial stem cells and innate immune cells in ALI/ARDS, concentrating on alveolar type 2 cells and alveolar macrophages and their contribution to post-injury repair behavior of ALI/ARDS through the latest potential molecular communication mechanisms. This will help to develop new research strategies and therapeutic targets for ALI/ARDS.

Investigation of the relationship of tissue-resident γδ T cells and IL-17 gene expression with the pathogenesis of autoimmune hepatitis

Autoimmune hepatitis (AIH) is a chronic inflammatory liver disease. Elevated serum immunoglobulin G (IgG) levels, autoantibodies, and histopathological interface hepatitis are the hallmarks of AIH. Autoantibodies and pathological findings, clinical and biochemical features, typical immunoglobulin levels, and exclusion of other diseases are used to diagnose the condition. Gamma-delta (γδ) T cells are a unique population of unconventional T cells with γ and δ glycoprotein chains. γδ T cells have been shown to play a crucial role in autoimmune diseases by producing interleukin (IL)-17. However, its role in AIH remains to be further elucidated. In this study, we aimed to examine the role of γδ T cells and IL-17 in the pathogenesis of AIH, by working on biopsy samples. Paraffin blocks of 18 patients with type 1 AIH and 18 control liver tissues were analyzed. qRT-PCR assessed IL-17 gene expression. Immunofluorescence double staining of CD3+TCRγδ+ was performed to reveal tissue-resident γδ T cells' role in AIH. When comparing AIH to the control, there was a substantial increase in the ratio of CD3+TCRγδ+ cells in total inflammatory cells (p = 0.01). IL-17 gene expression was lowered in AIH when compared to the control (p = 0.01). This study provides evidence for the involvement of γδ T cells and IL-17 in the pathogenesis of AIH. The ratio of γδ T cells and IL-17 gene expression showed a significant difference in AIH suggesting a potential role for γδ T cells in driving liver inflammation in A fIH.

CAR immunotherapy in autoimmune diseases: promises and challenges

In recent years, the use of chimeric antigen receptor (CAR)-T cells has emerged as a promising immunotherapy in multiple diseases. CAR-T cells are T cells genetically modified to express a surface receptor, known as CAR, for the targeting of cognate antigens on specific cells. The effectiveness of CAR-T cell therapy in hematologic malignancies including leukemia, myeloma, and non-Hodgkin's lymphoma has led to consider its use as a potential avenue of treatment for autoimmune diseases. However, broadening the use of CAR-T cell therapy to a large spectrum of autoimmune conditions is challenging particularly because of the possible development of side effects including cytokine release syndrome and neurotoxicity. The design of CAR therapy that include additional immune cells such as double-negative T cells, γδ T cells, T regulatory cells and natural killer cells has shown promising results in preclinical studies and clinical trials in oncology, suggesting a similar potential utility in the treatment of autoimmune diseases. This review examines the mechanisms, efficacy, and safety of CAR approaches with a focus on their use in autoimmune diseases including systemic lupus erythematosus, Sjögren's syndrome, systemic sclerosis, multiple sclerosis, myasthenia gravis, lupus nephritis and other autoimmune diseases. Advantages and disadvantages as compared to CAR-T cell therapy will also be discussed.

Hepatitis E virus: from innate sensing to adaptive immune responses

Hepatitis E virus (HEV) infections are a major cause of acute viral hepatitis in humans worldwide. In immunocompetent individuals, the majority of HEV infections remain asymptomatic and lead to spontaneous clearance of the virus, and only a minority of individuals with infection (5-16%) experience symptoms of acute viral hepatitis. However, HEV infections can cause up to 30% mortality in pregnant women, become chronic in immunocompromised patients and cause extrahepatic manifestations. A growing body of evidence suggests that the host immune response to infection with different HEV genotypes is a critical determinant of distinct HEV infection outcomes. In this Review, we summarize key components of the innate and adaptive immune responses to HEV, including the underlying immunological mechanisms of HEV associated with acute and chronic liver failure and interactions between T cell and B cell responses. In addition, we discuss the current status of vaccines against HEV and raise outstanding questions regarding the immune responses induced by HEV and treatment of the disease, highlighting areas for future investigation.

Chimerism-Mediated Tolerance in Intestinal Transplantation

In this review, the authors outlined concepts and strategies to achieve immune tolerance through inducing hematopoietic chimerism after solid organ transplantation and introduced challenges and opportunities in harnessing two-way alloresponses to improve outcomes after intestinal transplantation (ITx). Next, the authors discussed the dynamics and phenotypes of peripheral blood and intestinal graft T-cell subset chimerism and their association with outcomes. The authors also summarized studies on other types of immune cells after ITx and their potential participation in chimerism-mediated tolerance. The authors further discussed strategies and future directions to promote chimerism-associated tolerance after ITx to overcome rejection and minimize immunosuppression.

T cell exhaustion in human cancers

T cell exhaustion refers to a progressive state in which T cells become functionally impaired due to sustained antigenic stimulation, which is characterized by increased expression of immune inhibitory receptors, but weakened effector functions, reduced self-renewal capacity, altered epigenetics, transcriptional programme and metabolism. T cell exhaustion is one of the major causes leading to immune escape of cancer, creating an environment that supports tumor development and metastatic spread. In addition, T cell exhaustion plays a pivotal role to the efficacy of current immunotherapies for cancer. This review aims to provide a comprehensive view of roles of T cell exhaustion in cancer development and progression. We summerized the regulatory mechanisms that involved in T cell exhaustion, including transcription factors, epigenetic and metabolic reprogramming events, and various microenvironmental factors such as cytokines, microorganisms, and tumor autocrine substances. The paper also discussed the challenges posed by T cell exhaustion to cancer immunotherapies, including immune checkpoint blockade (ICB) therapies and chimeric antigen receptor T cell (CAR-T) therapy, highlightsing the obstacles encountered in ICB therapies and CAR-T therapies due to T cell exhaustion. Finally, the article provides an overview of current therapeutic options aimed to reversing or alleviating T cell exhaustion in ICB and CAR-T therapies. These therapeutic approaches seek to overcome T cell exhaustion and enhance the effectiveness of immunotherapies in treating tumors.

Potential of gamma/delta T cells for solid tumor immunotherapy

Gamma/delta T (γδ T)cells possess a unique mechanism for killing tumors, making them highly promising and distinguished among various cell therapies for tumor treatment. This review focuses on the major histocompatibility complex (MHC)-independent recognition of antigens and the interaction between γδ T cells and solid tumor cells. A comprehensive review is provided regarding the classification of human gamma-delta T cell subtypes, the characteristics and mechanisms underlying their functions, as well as their r545egulatory effects on tumor cells. The involvement of γδ T cells in tumorigenesis and migration was also investigated, encompassing potential therapeutic targets such as apoptosis-related molecules, the TNF receptor superfamily member 6(FAS)/FAS Ligand (FASL) pathways, butyrophilin 3A-butyrophilin 2A1 (BTN3A-BTN2A1) complexes, and interactions with CD4, CD8, and natural killer (NK) cells. Additionally, immune checkpoint inhibitors such as programmed cell death protein 1/Programmed cell death 1 ligand 1 (PD-1/PD-L1) have the potential to augment the cytotoxicity of γδ T cells. Moreover, a review on gamma-delta T cell therapy products and their corresponding clinical trials reveals that chimeric antigen receptor (CAR) gamma-delta T therapy holds promise as an approach with encouraging preclinical outcomes. However, practical issues pertaining to manufacturing and clinical aspects need resolution, and further research is required to investigate the long-term clinical side effects of CAR T cells. In conclusion, more comprehensive studies are necessary to establish standardized treatment protocols aimed at enhancing the quality of life and survival rates among tumor patients utilizing γδ T cell immunotherapy.

A Comprehensive Review on Porcine Reproductive and Respiratory Syndrome Virus with Emphasis on Immunity

Porcine reproductive and respiratory syndrome virus (PRRSV) is one of the most important pathogens in pig production worldwide and responsible for enormous production and economic losses. PRRSV infection in gestating gilts and sows induces important reproductive failure. Additionally, respiratory distress is observed in infected piglets and fattening pigs, resulting in growth retardation and increased mortality. Importantly, PRRSV infection interferes with immunity in the respiratory tract, making PRRSV-infected pigs more susceptible to opportunistic secondary pathogens. Despite the availability of commercial PRRSV vaccines for more than three decades, control of the disease remains a frustrating and challenging task. This paper provides a comprehensive overview of PRRSV, covering its history, economic and scientific importance, and description of the viral structure and genetic diversity. It explores the virus's pathogenesis, including cell tropism, viral entry, replication, stages of infection and epidemiology. It reviews the porcine innate and adaptative immune responses to comprehend the modulation mechanisms employed by PRRS for immune evasion.

SynGAP: a synteny-based toolkit for gene structure annotation polishing

Genome sequencing has become a routine task for biologists, but the challenge of gene structure annotation persists, impeding accurate genomic and genetic research. Here, we present a bioinformatics toolkit, SynGAP (Synteny-based Gene structure Annotation Polisher), which uses gene synteny information to accomplish precise and automated polishing of gene structure annotation of genomes. SynGAP offers exceptional capabilities in the improvement of gene structure annotation quality and the profiling of integrative gene synteny between species. Furthermore, an expression variation index is designed for comparative transcriptomics analysis to explore candidate genes responsible for the development of distinct traits observed in phylogenetically related species.

Dual role of circulating and mucosal Vδ1 T cells in the control of and contribution to persistent HIV-1 infection

Curative strategies for human immunodeficiency virus (HIV-1) infection are hindered by incomplete characterization of the latent reservoir and limited enhancement of anti-HIV immune responses. In this study, we identified a novel dual role for peripheral and tissue-resident Vδ1 T cells within the gastrointestinal mucosa of virally suppressed people with HIV. Phenotypic analyses identified an increased frequency of highly differentiated, cytotoxic effector Vδ1 T cells that exerted potent inhibition of HIV-1 replication in vitro coinciding with direct increases in cytolytic function. Conversely, we detected an enrichment of HIV-1 DNA in tissue-resident CD4+Vδ1 T cells in situ. Despite low CD4 expression, we found circulating Vδ1 T cells also contained HIV-1 DNA which was replication-competent. We show that TCR-mediated activation of peripheral Vδ1 T cells induced de novo upregulation of CD4 providing a plausible mechanism for increased permissibility to infection. These findings highlight juxtaposing roles for Vδ1 T cells in HIV-1 persistence including significant contribution to tissue reservoirs.

Nuclear-Based Labeling of Cellular Immunotherapies: A Simple Protocol for Preclinical Use

Labeling and tracking existing and emerging cell-based immunotherapies using nuclear imaging is widely used to guide the preclinical phases of development and testing of existing and new emerging off-the-shelf cell-based immunotherapies. In fact, advancing our knowledge about their mechanism of action and limitations could provide preclinical support and justification for moving towards clinical experimentation of newly generated products and expedite their approval by the Food and Drug Administration (FDA).Here we provide the reader with a ready to use protocol describing the labeling methodologies and practical procedures to render different candidate cell therapies in vivo traceable by nuclear-based imaging. The protocol includes sufficient practical details to aid researchers at all career stages and from different fields in familiarizing with the described concepts and incorporating them into their work.

The interplay between T lymphocytes and macrophages in myocardial ischemia/reperfusion injury

Acute myocardial infarction is one of the most important causes of death in the world, causing a huge health and economic burden to the world. It is still a ticklish problem how to effectively prevent reperfusion injury while recovering the blood flow of ischemic myocardium. During the process of myocardial ischemia/reperfusion injury (MI/RI), the modulation of immune cells plays an important role. Monocyte/macrophage, neutrophils and endothelial cells initiate the inflammatory response and induce the release of various inflammatory cytokines, resulting in increased vascular permeability, tissue edema and damage. Meanwhile, T cells were recruited to impaired myocardium and release pro-inflammatory and anti-inflammatory cytokines. T cells and macrophages play important roles in keeping cardiac homeostasis and orchestrate tissue repair. T cells differentiation and macrophages polarization precisely regulates the tissue microenvironment in MI/RI, and shows cross action, but the mechanism is unclear. To identify potential intervention targets and propose ideas for treatment and prevention of MI/RI, this review explores the crosstalk between T lymphocytes and macrophages in MI/RI.

γδ T cells as critical anti-tumor immune effectors

While the effector cells that mediate anti-tumor immunity have historically been attributed to αβ T cells and natural killer cells, γδ T cells are now being recognized as a complementary mechanism mediating tumor rejection. γδ T cells possess a host of functions ranging from antigen presentation to regulatory function and, importantly, have critical roles in eliciting anti-tumor responses where other immune effectors may be rendered ineffective. Recent discoveries have elucidated how these differing functions are mediated by γδ T cells with specific T cell receptors and spatial distribution. Their relative resistance to mechanisms of dysfunction like T cell exhaustion has spurred the development of therapeutic approaches exploiting γδ T cells, and an improved understanding of these cells should enable more effective immunotherapies.