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Acute Respiratory Distress Syndrome (ARDS) is an illness that typically develops in people who are significantly ill or have serious injuries. ARDS is characterized by fluid build-up that occurs in the alveoli. T-cells are implicated as playing a role in the modulation of the aberrant response leading to excessive tissue damage and, eventually, ARDS. Complementarity Determining Region 3 (CDR3) sequences derived from T-cells are key players in the adaptive immune response. This response is governed by an elaborate specificity for distinct molecules and the ability to recognize and vigorously respond to repeated exposures to the same molecules. Most of the diversity in T-cell receptors (TCRs) is contained in the CDR3 regions of the heterodimeric cell-surface receptors. For this study, we employed the novel technology of immune sequencing to assess lung edema fluid. Our goal was to explore the landscape of CDR3 clonal sequences found within these samples. We obtained more than 3615 CDR3 sequences across samples in the study. Our data demonstrate that: (1) CDR3 sequences from lung edema fluid exhibit distinct clonal populations, and (2) CDR3 sequences can be further characterized based on biochemical features. Analysis of these CDR3 sequences offers insight into the CDR3-driven T-cell repertoire of ARDS. These findings represent the first step towards applications of this technology with these types of biological samples in the context of ARDS.

The adaptive immune system employs a large number of T cells, that each have a specificity defined by their T-cell receptor (TCR). Characterizing the TCR repertoire in humans and mice thus provides a way to address outstanding immunological questions. The repertoires can be assessed quantitatively using high-throughput sequencing. Interpretation of the resulting data is challenging due to the vast diversity of the TCR repertoire and the relatively small number of cells that can be analyzed in an experiment. In this thesis we analyze TCR repertoires from humans and mice, by integrating information obtained from multiple samples. In Chapter 2 we devise various models for the distribution of TCR clone sizes in the human naive T cell pool. We characterise the repertoire of TCR α and β chains by repertoire sequencing of various cell subsets. Comparing the model predictions with the experimental outcomes, we find solid evidence for the presence of very large TCRαβ clones in the naive T cell repertoire. These large naive T-cell clones are only partly explained by their generation probability. Chapter 3 aims to identify sequence characteristics of such abundant naive T cell clones. We find that the D segment is missing in a substantial fraction of the abundant TCR β sequences in the naive T cell repertoire of young individuals. Such sequences appear to be mostly generated before birth, to persist over a human lifetime, and, as a result, to be excessively shared between individuals. Chapter 4 is a short unpublished report on quantifying the effects of age on the TCR repertoire. We present example analyses and discuss potential pitfalls of assessing ageing effects on the TCR repertoire. Chapter 5 describes a pilot study on using TCR sequencing to follow the T-cell response upon pneumococcal conjugate vaccination. We define quantitative requirements to classify T-cell expansions but detect these in only a minority of the donors. Our analysis suggests that the vaccine-induced T-cell response is small and/or very broad, and highlights experimental requirements to characterise such responses in future studies. A key limitation of the studies in humans introduced above is the limited number of cells that can be analysed compared to the total size of the T-cell pool. As a result, many of the TCR chains that make up the diversity of the TCR repertoire will be missed in any analysis. Bulk sequencing methods also do not uncover the full TCR diversity present in an individual as the information on the pairing of α and β chains is not obtained. In Chapter 6 we overcome both limitations by studying the TCR repertoire of one-TCRa mice that have a strongly reduced receptor diversity. This allows us to study the nearly complete TCR diversity, and compare the repertoire among individual lymph nodes and mice, revealing a spatial organisation of the TCR repertoire. In summary, this thesis describes how we studied T-cell biology quantitatively by combining simplified models with careful bioinformatics analyses.

The adaptive immune system employs a large number of T cells, that each have a specificity defined by their T-cell receptor (TCR). Characterizing the TCR repertoire in humans and mice thus provides a way to address outstanding immunological questions. The repertoires can be assessed quantitatively using high-throughput sequencing. Interpretation of the resulting data is challenging due to the vast diversity of the TCR repertoire and the relatively small number of cells that can be analyzed in an experiment. In this thesis we analyze TCR repertoires from humans and mice, by integrating information obtained from multiple samples. In Chapter 2 we devise various models for the distribution of TCR clone sizes in the human naive T cell pool. We characterise the repertoire of TCR α and β chains by repertoire sequencing of various cell subsets. Comparing the model predictions with the experimental outcomes, we find solid evidence for the presence of very large TCRαβ clones in the naive T cell repertoire. These large naive T-cell clones are only partly explained by their generation probability. Chapter 3 aims to identify sequence characteristics of such abundant naive T cell clones. We find that the D segment is missing in a substantial fraction of the abundant TCR β sequences in the naive T cell repertoire of young individuals. Such sequences appear to be mostly generated before birth, to persist over a human lifetime, and, as a result, to be excessively shared between individuals. Chapter 4 is a short unpublished report on quantifying the effects of age on the TCR repertoire. We present example analyses and discuss potential pitfalls of assessing ageing effects on the TCR repertoire. Chapter 5 describes a pilot study on using TCR sequencing to follow the T-cell response upon pneumococcal conjugate vaccination. We define quantitative requirements to classify T-cell expansions but detect these in only a minority of the donors. Our analysis suggests that the vaccine-induced T-cell response is small and/or very broad, and highlights experimental requirements to characterise such responses in future studies. A key limitation of the studies in humans introduced above is the limited number of cells that can be analysed compared to the total size of the T-cell pool. As a result, many of the TCR chains that make up the diversity of the TCR repertoire will be missed in any analysis. Bulk sequencing methods also do not uncover the full TCR diversity present in an individual as the information on the pairing of α and β chains is not obtained. In Chapter 6 we overcome both limitations by studying the TCR repertoire of one-TCRa mice that have a strongly reduced receptor diversity. This allows us to study the nearly complete TCR diversity, and compare the repertoire among individual lymph nodes and mice, revealing a spatial organisation of the TCR repertoire. In summary, this thesis describes how we studied T-cell biology quantitatively by combining simplified models with careful bioinformatics analyses.

The adaptive immune system employs a large number of T cells, that each have a specificity defined by their T-cell receptor (TCR). Characterizing the TCR repertoire in humans and mice thus provides a way to address outstanding immunological questions. The repertoires can be assessed quantitatively using high-throughput sequencing. Interpretation of the resulting data is challenging due to the vast diversity of the TCR repertoire and the relatively small number of cells that can be analyzed in an experiment. In this thesis we analyze TCR repertoires from humans and mice, by integrating information obtained from multiple samples. In Chapter 2 we devise various models for the distribution of TCR clone sizes in the human naive T cell pool. We characterise the repertoire of TCR α and β chains by repertoire sequencing of various cell subsets. Comparing the model predictions with the experimental outcomes, we find solid evidence for the presence of very large TCRαβ clones in the naive T cell repertoire. These large naive T-cell clones are only partly explained by their generation probability. Chapter 3 aims to identify sequence characteristics of such abundant naive T cell clones. We find that the D segment is missing in a substantial fraction of the abundant TCR β sequences in the naive T cell repertoire of young individuals. Such sequences appear to be mostly generated before birth, to persist over a human lifetime, and, as a result, to be excessively shared between individuals. Chapter 4 is a short unpublished report on quantifying the effects of age on the TCR repertoire. We present example analyses and discuss potential pitfalls of assessing ageing effects on the TCR repertoire. Chapter 5 describes a pilot study on using TCR sequencing to follow the T-cell response upon pneumococcal conjugate vaccination. We define quantitative requirements to classify T-cell expansions but detect these in only a minority of the donors. Our analysis suggests that the vaccine-induced T-cell response is small and/or very broad, and highlights experimental requirements to characterise such responses in future studies. A key limitation of the studies in humans introduced above is the limited number of cells that can be analysed compared to the total size of the T-cell pool. As a result, many of the TCR chains that make up the diversity of the TCR repertoire will be missed in any analysis. Bulk sequencing methods also do not uncover the full TCR diversity present in an individual as the information on the pairing of α and β chains is not obtained. In Chapter 6 we overcome both limitations by studying the TCR repertoire of one-TCRa mice that have a strongly reduced receptor diversity. This allows us to study the nearly complete TCR diversity, and compare the repertoire among individual lymph nodes and mice, revealing a spatial organisation of the TCR repertoire. In summary, this thesis describes how we studied T-cell biology quantitatively by combining simplified models with careful bioinformatics analyses.

T cells monitor the health status of cells by identifying foreign peptides displayed on their surface. T-cell receptors (TCRs), which are protein complexes found on the surface of T cells, are able to bind to these peptides. This process is known as TCR recognition and constitutes a key step for immune response. Optimizing TCR sequences for TCR recognition represents a fundamental step towards the development of personalized treatments to trigger immune responses killing cancerous or virus-infected cells. In this paper, we formulated the search for these optimized TCRs as a reinforcement learning (RL) problem, and presented a framework TCRPPO with a mutation policy using proximal policy optimization. TCRPPO mutates TCRs into effective ones that can recognize given peptides. TCRPPO leverages a reward function that combines the likelihoods of mutated sequences being valid TCRs measured by a new scoring function based on deep autoencoders, with the probabilities of mutated sequences recognizing peptides from a peptide-TCR interaction predictor. We compared TCRPPO with multiple baseline methods and demonstrated that TCRPPO significantly outperforms all the baseline methods to generate positive binding and valid TCRs. These results demonstrate the potential of TCRPPO for both precision immunotherapy and peptide-recognizing TCR motif discovery., 27th Annual International Conference, RECOMB 2023, April 16–19, 2023, Istanbul, Turkey, Series: Lecture Notes in Computer Science

International audience; Lichen planus (LP) is a cutaneomucosal chronic inflammatory disease characterized by a CD8 + cytotoxic T-lymphocytes (CTL) infiltrate. In erosive oral LP, we found HPV16specific activated CTL in lesions, supporting a pathogenic contribution of HPV16. Here, we investigated whether a similar scenario occurs in other clinical forms of LP and in lichen sclerosus et atrophicus (LSA), another chronic disease also affecting the mucosa and/or the skin. Blood CTL from LP and LSA patients expressed significant higher levels of granzyme B, perforin and CD107a proteins than healthy donors. Expansions of TCRVß3 + CTL, with presence of TCR clonotypes identical to those previously detected in erosive oral LP, were found both in blood and mucosal/skin lesions of LP, and not of LSA patients. These expansions were enriched with HPV16-specific CD8 + T-cells as shown by their recognition of the E7 11-20 immunodominant epitope. In LSA patients, the peripheral repertoire of CTL was oligoclonal for TCRVß6 + CTL. Finally, although patients with LP and LSA have developed antibodies against HPV16

T cell engaged bispecific antibody (TCB) is an effective immunotherapy for cancer treatment. Through co-targeting CD3 and tumor-associated antigen (TAA), TCB can redirect CD3+ T cells to eliminate tumor cells regardless of the specificity of T cell receptor. Tissue factor (TF) is a TAA that involved in tumor progression. Here, we designed and characterized a novel TCB targeting TF (TF-TCB) for the treatment of TF-positive tumors. In vitro, robust T cell activation, tumor cell lysis and T cell proliferation were induced by TF-TCB. The tumor cell lysis activity was dependent upon both CD3 and TF binding moieties of the TF-TCB, and was related to TF expression level of tumor cells. In vivo, in both tumor cell/human peripheral blood mononuclear cells (PBMC) co-grafting model and established tumor models with poor T cell infiltration, tumor growth was strongly inhibited by TF-TCB. T cell infiltration into tumors was induced during the treatment. Furthermore, efficacy of TF-TCB was further improved by combination with immune checkpoint inhibitors. For the first time, our results validated the feasibility of using TF as a target for TCB and highlighted the potential for TF-TCB to demonstrate efficacy in solid tumor treatment.

Background aims Given their low immunogenicity, immunoregulatory effects and multiple differentiation capacity, mesenchymal stromal cells (MSCs) have the potential to be used for “off-the-shelf” cell therapy to treat various diseases. However, the allorejection of MSCs indicates that they are not fully immune-privileged. In this study, the authors investigated the immunogenicity of human adipose-derived MSCs (Ad-MSCs) and identified potential immunogenic molecules. Methods To evaluate the immunogenicity of human Ad-MSCs in vivo, cells were transplanted into humanized mice (hu-mice), then T-cell infiltration and clearance of human Ad-MSCs were observed by immunofluorescence and bioluminescence imaging. One-way mixed lymphocyte reaction and flow cytometry were performed to evaluate the immunogenicity of human Ad-MSCs in vitro. High-throughput T-cell receptor (TCR) repertoire sequencing and mass spectrometry were applied to identified potential immunogenic molecules. Results The authors observed that allogeneic Ad-MSCs recruited human T cells and caused faster clearance in hu-mice than non-humanized NOD.Cg-Prkdcscid IL2rgtm1Wjl/SzJ (NSG) mice. The proliferation and activation of T cells were significantly enhanced during in vitro co-culture with human Ad-MSCs. In addition, the level of HLA-II expression on human Ad-MSCs was dramatically increased after co-culture with human peripheral blood mononuclear cells (PBMCs). High-throughput sequencing was applied to analyze the TCR repertoire of the Ad-MSC-recruited T cells to identify dominant TCR CDR3 sequences. Using synthesized TCR CDR3 peptides, the authors identified several potential immunogenic candidates, including alpha-enolase (ENO1). The ENO1 expression level of Ad-MSCs significantly increased after co-culture with PBMCs, whereas ENO1 inhibitor (ENOblock) treatment decreased the expression level of ENO1 and Ad-MSC-induced proliferation of T cells. Conclusions The authors’ findings improve the understanding of the immunogenicity of human Ad-MSCs and provide a theoretical basis for the safe clinical application of allogeneic MSC therapy.

Atopic dermatitis (AD) and psoriasis represent two of the most common inflammatory skin diseases in developed countries. A hallmark of both diseases is T cell infiltration into the skin. However, it is still not clarified to what extent these infiltrating T cells are antigen-specific skin-homing T cells or unspecific heterogeneous bystander cells. To elucidate this, T cells from lesional skin and from blood of 10 AD and 11 psoriasis patients were compared by receptor (TCR) sequencing. Therefore, peripheral blood mononuclear cells (PBMC) were cell-sorted according to expression of the cutaneous leukocyte antigen (CLA) into skin-homing (CLA+) and non-skin-homing (CLA-) subfractions. Aeroallergen-specific T cell lines were grown from AD patients’ s PBMC in parallel. Intra-individual comparison of TCRB CDR3 regions revealed that clonally expanded T cells in skin lesions of both AD and psoriasis patients corresponded to skin-homing circulating T cells. However, in psoriasis patients, these T cell clones were also detectable to a larger extent among CLA- circulating T cells. Up to 28% of infiltrating cells were identified as allergen-specific by overlapping TCR sequences. Our data shows that in line with the systemic nature of psoriasis, T cells infiltrating psoriatic skin lesions do not exclusively home to the skin and are therefore not specific to antigens that are exclusively encountered at the skin. T cells driving AD skin inflammation appear to home nearly exclusively to the skin and are, to a certain extent, specific to aeroallergens. One Sentence Summary In contrast to psoriasis, T cells driving atopic dermatitis are predominantly skin-homing and are to a certain extent allergen-specific Key Message / Significance Statement T cells that encounter their cognate antigen proliferate clonally and share the same T cell receptor (TCR). Here we describe that clonally expanded T cells from lesional skin in patients with psoriasis and atopic dermatitis (AD) can also be detected within the circulation. While in AD these are mostly homing to the skin, psoriasis-driving T cells do not appear to be exclusively skin-directed. The fact that several co-morbidities are associated with psoriasis matches this observation. In contrast, AD is commonly accompanied by allergic sensitizations. Here we demonstrate that allergen-specific T cells do indeed infiltrate lesional skin and allow a concrete estimate of their frequency.

This work presented a self-excited induction generator (SEIG) model controlled by an (FC-TCR) fixed capacitor-thyristor control reactor consisting of a large fixed capacitor in parallel with a thyristor controlled reactor in series with the constant inductance. Induction machines were used because they are capable of working at different speeds. The 3-phase IG was driven by the prime mover that represents the wind turbine. Also, constant voltage and frequency were obtained, regardless of the change in velocity, by using proportional integration (PI control) for each of them. This type of generator is used in isolated rural areas far from power transmission lines. The voltage and frequency are analyzed for each wind speed proposed in the model and calculating the required excitation amplitude and torque required to drive the induction generator. Therefore, it is now a key interest to develop an efficient, viable, economic, and controllable induction generator for harnessing energy from renewable sources. The strategy of control was implemented with MATLAB/Simulink.

T cells must be activated and become effectors first before executing allograft rejection, a process that is regulated by diverse signals and transcription factors. In the present study, we studied the basic leucine zipper ATF-like transcription factor (BATF) family members in regulating T cell activities in a heart transplant model and found that mice deficient for both BATF and BATF3 (Batf(−/−)Batf3(−/−) mice) spontaneously accept the heart allografts long-term without tolerizing therapies. Similarly, adoptive transfer of wild type T cells into Rag1(−/−) hosts induced prompt rejection of heart and skin allografts, whereas the Batf(−/−)Batf3(−/−) T cells failed to do so. Analyses of graft-infiltrating cells showed that Batf(−/−)Batf3(−/−) T cells infiltrate the graft but fail to acquire an effector phenotype (CD44(high)KLRG1(+)). Co-transfer experiments in a TCR transgenic TEa model revealed that the Batf(−/−)Batf3(−/−) T cells fail to expand in vivo, retain a quiescent phenotype (CD62L(+)CD127(+)), and unable to produce effector cytokines to alloantigen stimulation, which contrasted sharply to that of wild type T cells. Together, our data demonstrate that the BATF and BATF3 are critical regulators of T effector functions, thus making them attractive targets for therapeutic interventions in transplant settings.

Engineered T cell therapies, mainly chimeric antigen receptor (CAR)-T and T cell receptor (TCR)-T, have become the new frontier of cancer treatment. CAR-T and TCR-T therapies differ in many aspects, including cell persistence and toxicity, leading to different therapeutic outcomes. Both TCR and CAR recognize antigens and trigger T cell mediated antitumor response, but they have distinct molecular structures and signaling properties. TCR represents one of the most complex receptors, while CAR is a single-chain chimera integrating modules from multiple immune receptors. Understanding the mechanisms underlying the strengths and limitations of both systems can pave the way for the development of next-generation T cell therapy. This review synthesizes recent findings on TCR and CAR signaling and highlights the potential strategies of T cell engineering by signaling refinement.

T cells engineered to express transgenes such as chimeric antigen receptors (CAR) or modified T cell receptors (TCR) represent a new pillar of cancer therapy. Use of CRISPR/Cas gene-editing tools now allows even stronger and more precise control over the fate and function of engineered T cell therapies, including multiplex genome editing to facilitate use of off-the-shelf allogeneic T cells and novel approaches which have the potential to overcome some of the limitations of canonical Cas9-mediated DNA cleavage. This review summarizes the CRISPR/Cas techniques that have been used in preclinical research and outlines those that currently being tested in clinical trials.

Dear Editor, Growing evidence suggests that SARS‐CoV‐2 vaccination is associated with a variety of cutaneous reactions, also including autoimmune‐mediated conditions such as autoimmune blistering diseases such as bullous pemphigoid (BP).1,2 We report new‐onset BP in two patients following the first SARS‐CoV‐2 vaccination.

Viral infections cause life-threatening disease in immunocompromised patients and especially following transplantation. T cell receptor (TCR) engineering redirects specificity and can bring significant progress to emerging adoptive T cell transfer (ACT) approaches. T cell epitopes are well described, although knowledge is limited on which TCRs mediate protective immunity. In this study, refractory adenovirus (AdV) infection after hematopoietic stem cell transplantation (HSCT) was treated with ACT of highly purified Hexon5-specific T cells using peptide major histocompatibility complex (pMHC)-Streptamers against the immunodominant human leukocyte antigen (HLA)-A∗0101-restricted peptide LTDLGQNLLY. AdV was successfully controlled through this oligoclonal ACT. Novel protective TCRs were isolated ex vivo and preclinically engineered into the TCR locus of allogeneic third-party primary T cells by CRISPR-Cas9-mediated orthotopic TCR replacement. Both TCR knockout and targeted integration of the new TCR in one single engineering step led to physiological expression of the transgenic TCR. Reprogrammed TCR-edited T cells showed strong virus-specific functionality such as cytokine release, effector marker upregulation, and proliferation capacity, as well as cytotoxicity against LTDLGQNLLY-presenting and AdV-infected targets. In conclusion, ex vivo isolated TCRs with clinical proven protection through ACT could be redirected into T cells from naive third-party donors. This approach ensures that transgenic TCRs are protective with potential off-the-shelf use and widened applicability of ACT to various refractory emerging viral infections.

Hypomethylating agents (HMA) like azacitidine are licensed for the treatment of acute myeloid leukemia (AML) patients ineligible for allogeneic hematopoietic stem cell transplantation. Biomarker-driven identification of HMA-responsive patients may facilitate the choice of treatment, especially in the challenging subgroup above 60 years of age. Since HMA possesses immunomodulatory functions that constitute part of their anti-tumor effect, we set out to analyze the bone marrow (BM) immune environment by next-generation sequencing of T cell receptor beta (TRB) repertoires in 51 AML patients treated within the RAS-AZIC trial. Patients with elevated pretreatment T cell diversity (11 out of 41 patients) and those with a boost of TRB richness on day 15 after azacitidine treatment (12 out of 46 patients) had longer event-free and overall survival. Both pretreatment and dynamic BM T cell metrics proved to be better predictors of outcome than other established risk factors. The favorable broadening of the BM T cell space appeared to be driven by antigen since these patients showed significant skewing of TRBV gene usage. Our data suggest that one course of AZA can cause reconstitution to a more physiological T cell BM niche and that the T cell space plays an underestimated prognostic role in AML. Trial registration: DRKS identifier: DRKS00004519

Adoptive T cell therapy with T cells expressing affinity-enhanced TCRs has shown promising results in phase 1/2 clinical trials for solid and hematological tumors. However, depth and durability of responses to adoptive T cell therapy can suffer from an inhibitory tumor microenvironment. A common immune-suppressive agent is TGF-β, which is secreted by tumor cells and cells recruited to the tumor. We investigated whether human T cells could be engineered to be resistant to inhibition by TGF-β. Truncating the intracellular signaling domain from TGF-β receptor (TGFβR) II produces a dominant-negative receptor (dnTGFβRII) that dimerizes with endogenous TGFβRI to form a receptor that can bind TGF-β but cannot signal. We previously generated specific peptide enhanced affinity receptor TCRs recognizing the HLA-A*02–restricted peptides New York esophageal squamous cell carcinoma 1 (NY-ESO-1)157–165/l-Ag family member-1A (TCR: GSK3377794, formerly NY-ESO-1c259) and melanoma Ag gene A10254–262 (TCR: ADP-A2M10, formerly melanoma Ag gene A10c796). In this article, we show that exogenous TGF-β inhibited in vitro proliferation and effector functions of human T cells expressing these first-generation high-affinity TCRs, whereas inhibition was reduced or abolished in the case of second-generation TCRs coexpressed with dnTGFβRII (e.g., GSK3845097). TGF-β isoforms and a panel of TGF-β–associated genes are overexpressed in a range of cancer indications in which NY-ESO-1 is commonly expressed, particularly in synovial sarcoma. As an example, immunohistochemistry/RNAscope identified TGF-β–positive cells close to T cells in tumor nests and stroma, which had low frequencies of cells expressing IFN-γ in a non–small cell lung cancer setting. Coexpression of dnTGFβRII may therefore improve the efficacy of TCR-transduced T cells.

Contains fulltext : 248576.pdf (Publisher’s version ) (Open Access) Single-cell antigen-receptor gene amplification and sequencing platforms have been used to characterize T cell receptor (TCR) repertoires but typically fail to generate paired full-length gene products for direct expression cloning and do not enable linking this data to cell phenotype information. To overcome these limitations, we established a high-throughput platform for the quantitative and qualitative analysis of human TCR repertoires that provides insights into the clonal and functional composition of human CD4(+) and CD8(+) αβ T cells at the molecular and cellular level. The strategy is a powerful tool to qualitatively assess differences between antigen receptors of phenotypically defined αβ T cell subsets, e.g. in immune responses to cancer, vaccination, or infection, and in autoimmune diseases.

Although adoptive transfer of T cells genetically engineered to express chimeric antigen receptor (CAR) or T-cell receptor (TCR) has been actively developed and applied into clinic recently, further improvement of these modalities is highly demanded, especially in terms of its efficacy. Because we previously revealed the profound enhancement of antitumor effects of CAR T cells by concomitant expression of IL7 and CCL19, this study further explored a potential of IL7/CCL19 production technology to augment antitumor effects of TCR T cells. IL7/CCL19-producing P1A tumor antigen-specific TCR T cells (7 × 19 P1A T cells) demonstrated significantly improved antitumor effects, compared with those without IL7/CCL19 production, and generated long-term memory responses. The antitumor effects of 7×19 P1A T cells were further upregulated by combination with anti–PD-1 antibody, in which blockade of PD-1 signal in both 7×19 P1A T cells and endogenous T cells plays an important role. Taken together, our study demonstrated that concomitant production of IL7 and CCL19 by genetically engineered tumor-reactive T cells could synergize with PD-1 blockade therapy to generate potent and long-lasting antitumor immunity.

Chimeric antigen receptors (CARs) can redirect T cells to target abnormal cells, but their activity is limited by a profound defect in antigen sensitivity, the source of which remains unclear. Here, we show that CARs have a > 100-fold lower antigen sensitivity compared to the T cell receptor (TCR) when antigen is presented on antigen-presenting cells (APCs) but nearly identical sensitivity when antigen is presented as purified protein. We next systematically measured the impact of engaging important T cell accessory receptors (CD2, LFA-1, CD28, CD27, and 4-1BB) on antigen sensitivity by adding their purified ligands. Unexpectedly, we found that engaging CD2 or LFA-1 improved the antigen sensitivity of the TCR by 125- and 22-fold, respectively, but improved CAR sensitivity by only < 5-fold. This differential effect of CD2 and LFA-1 engagement on the TCR vs. CAR was confirmed using APCs. We found that sensitivity to antigen can be partially restored by fusing the CAR variable domains to the TCR CD3 ε subunit (also known as a TRuC) and fully restored by exchanging the TCR α β variable domains for those of the CAR (also known as STAR or HIT). Importantly, these improvements in TRuC and STAR/HIT sensitivity can be predicted by their enhanced ability to exploit CD2 and LFA-1. These findings demonstrate that the CAR sensitivity defect is a result of their inefficient exploitation of accessory receptors and suggest approaches to increase sensitivity.

FKBP51 is constitutively expressed by immune cells. As other FKBP family members, FKBP51 acts as a coreceptor for the natural products FK506 and rapamycin, which exhibit immunosuppressive effects. However, little is known about the intrinsic role of this large FKBP in the primary function of lymphocytes, that is, the adaptive immune response against foreign antigens, for example, pathogens. This paper aimed to investigate whether FKBP51 expression was modulated during lymphocyte activation. Moreover, as we recently identified a splicing isoform of FKBP51, namely FKBP51s, we also measured this splice protein, along with the canonical one, at different times of a peripheral blood mononuclear cell culture stimulated via T cell receptor. Our results show that the two FKBP51 isoforms were alternatively induced during the proliferative burst. Canonical FKBP51 increased in the time window between 48 and 96 h and its expression levels correlated with cyclin D levels. FKBP51s transiently increased earlier, at 24-36 h to reappearing later, at 120 h, when cyclin D expression returned at resting levels and proliferation ceased. Interestingly, within these two specific timeframes, FKBP51s accumulated in the nucleus. Here FKBP51s colocalized with the Foxp3 transcription factor at 36 h. Regulatory T cell (Treg) counts significantly decreased when FKBP51s was downmodulated. The coculture suppression assay suggested that FKBP51s supports the suppressive capability of Tregs. At 120 h, chromatin immunoprecipitation experiments found FKBP51s linked to CCND1 gene, suggesting a possible effect on gene transcription regulation, as previously demonstrated in melanoma. In conclusion, our study shows that FKBP5 isoforms are upregulated during lymphocyte activation, albeit on different timeframes. The activation of canonical FKBP51 coincides with proliferation hallmarks; FKBP5 splicing occurs early to sustain Treg development and late when proliferation ceases.

Objectives Antinuclear antibody (ANA) positive Juvenile Idiopathic Arthritis (JIA) is characterized by synovial B cell hyperactivity, but the precise role of CD4+ T cells in promoting local B cell activation is unknown. The objective of this study is to unravel the phenotype and function of synovial CD4+ T cells that promote the aberrant B cell activation in JIA. Methods Flow cytometric analysis was performed to compare the phenotype and cytokine pattern of synovial fluid (SF) PD-1hi CD4+ T cells with tonsil TFH cells. TCRVB next generation sequencing was applied to analyze T cell subsets for signs of clonal expansion. The functional impact of these T cell subsets on B cells was dissected in in vitro co-cultures. Results Multidimensional flow-cytometric analysis revealed the expansion of IL-21 and IFN-γ co-expressing PD-1hi CXCR5- HLA-DR+ CD4+ T cells that accumulate in the joints of ANA+ JIA patients. These T cells exhibited signs of clonal expansion with restricted TCR clonotypes. Phenotypically they resembled peripheral T helper (TPH ) cells with an extrafollicular chemokine receptor pattern and high T-bet and Blimp-1 but low Bcl-6 expression. SF TPH cells particularly skewed B cell differentiation towards a CD21lo/- CD11c+ phenotype by provision of IL-21 and IFN-γ in vitro and correlated with the appearance of SF CD21lo/- CD11c+ CD27- IgM- double-negative B cells (BDN ) in situ. Conclusion Clonally expanded CD4+ TPH cells accumulate in the joints of ANA+ JIA patients and particularly promote CD21lo/- CD11c+ BDN cell differentiation The expansion of TPH and BDN cells might reflect the autoimmune response present in the joints of ANA+ JIA patients.

CD8+ T cells are key mediators of antiviral and antitumor immunity. The isolation and study of Ag-specific CD8+ T cells, as well as mapping of their MHC restriction, has practical importance to the study of disease and the development of therapeutics. Unfortunately, most experimental approaches are cumbersome, owing to the highly variable and donor-specific nature of MHC-bound peptide/TCR interactions. Here we present a novel system for rapid identification and characterization of Ag-specific CD8+ T cells, particularly well suited for samples with limited primary cells. Cells are stimulated ex vivo with Ag of interest, followed by live cell sorting based on surface-trapped TNF-α. We take advantage of major advances in single-cell sequencing to generate full-length sequence data from the paired TCR α- and β-chains from these Ag-specific cells. The paired TCR chains are cloned into retroviral vectors and used to transduce donor CD8+ T cells. These TCR transductants provide a virtually unlimited experimental reagent, which can be used for further characterization, such as minimal epitope mapping or identification of MHC restriction, without depleting primary cells. We validated this system using CMV-specific CD8+ T cells from rhesus macaques, characterizing an immunodominant Mamu-A1*002:01-restricted epitope. We further demonstrated the utility of this system by mapping a novel HLA-A*68:02-restricted HIV Gag epitope from an HIV-infected donor. Collectively, these data validate a new strategy to rapidly identify novel Ags and characterize Ag-specific CD8+ T cells, with applications ranging from the study of infectious disease to immunotherapeutics and precision medicine.

Granzyme B (GrB)-producing B cells are proposed to be a kind of regulatory B cells (Bregs) and have been revealed to be implicated in the pathogenesis of autoimmune diseases. Nevertheless, their role in SLE remains elusive. In this study, the frequencies of GrB-producing Bregs in peripheral blood of heathy control (HC) and systemic lupus erythematosus (SLE) were evaluated by flow cytometry, and their correlation with SLE patient clinical and immunological features were analyzed. The expression of GrB in HC and SLE B cells were also further detected by RT-qPCR analysis and ELISpot. The function of GrB-producing Bregs in HC and SLE patients was further investigated by in vitro CD4+ effector T cells-B cells co-culture assays with GrB blockade. We found that GrB-producing Bregs were significantly decreased in SLE patients and correlated with the clinical and immunological features. Moreover, these cells were functionally impaired under SLE circumstance. The negative correlation between GrB-producing Bregs and CD4+ T cells observed in healthy individuals disappeared in SLE patients. In vitro cell co-culture assay further showed that GrB-producing Bregs from SLE patients failed to suppress the Th1, Th2 and Th17 cell inflammatory responses, partially due to the dampened capacity of down-regulating TCR zeta and inducing T cell apoptosis. Taken together, these results revealed the disturbance of GrB-producing Bregs in SLE that might contribute to the disease initiation and progression.

Mature CD4(+) and CD8(+) T cells constitutively experience weak T cell receptor (TCR) stimulation in response to self-antigens, termed tonic (or basal) signaling. How tonic TCR signal strength impacts T cell responses to foreign antigens is an active area of investigation. Such studies rely on surrogate markers of tonic signal strength, including CD5, Ly6C, and transgenic reporters of Nr4a genes. Recent research indicates that strong tonic TCR signal strength influences basal T cell metabolism, effector differentiation, and TCR signal transduction. T cells that experience the strongest tonic TCR signaling exhibit features of T cell activation and negative regulation. These data suggest a model whereby adaptation to tonic signaling has lasting effects that alter T cell activation and differentiation.

Background Early detection of lung cancer in asymptomatic patients remains challenging, especially for stage I. Considering the substantial interaction with tumor immunogenicity, we hypothesized that lung cancer-associated TCR (LC-aTCR) may serve as potential biomarker in early detection of stage I lung cancer. Methods Individuals who received low-dose computed tomography (LDCT) screening were enrolled in the study. Surgical tissues and peripheral blood specimens were collected and performed with DNA-based T cell repertoire (TCR) sequencing. The motif-based algorithm was used to deconstruct specific lung cancer-associated TCRs (LC-aTCRs). Results A total of 146 individuals participating in the real-world LDCT screening project were enrolled in this study, including 52 patients with pathologically-confirmed stage I lung cancer and 94 non-cancer controls. We developed a motif-based algorithm to define 80 LC-aTCRs in the training cohort. Moreover, in the validation cohort, high sensitivity and specificity was showed in stage I lung cancer with 72% and 91% respectively, and the AUC of the ROC curve was 0.91 (95% CI: 0.85 ∼ 0.96). Conclusion This work provides inspiration for stage I lung cancer detection by using blood TCR profiling data. The combination of TCR-based assay and routine screening deserves further testing in larger cohorts.

T cells recognize mycobacterial glycolipid (mycolipid) antigens presented by CD1b molecules, but the role of CD4 and CD8 co-receptors in mycolipid recognition is unknown. Here we show CD1b-mycolipid tetramers reveal a hierarchy in which circulating T cells expressing CD4 or CD8 co-receptor stain with a higher tetramer mean fluorescence intensity than CD4-CD8- T cells. CD4+ primary T cells transduced with mycolipid-specific T cell receptors bind CD1b-mycolipid tetramer with a higher fluorescence intensity than CD8+ primary T cells. The presence of either CD4 or CD8 also decreases the threshold for interferon-γ secretion. Co-receptor expression increases surface expression of CD3ε, suggesting a mechanism for increased tetramer binding and activation. Targeted transcriptional profiling of mycolipid-specific T cells from individuals with active tuberculosis reveals canonical markers associated with cytotoxicity among CD8+ compared to CD4+ T cells. Thus, expression of co-receptors modulates T cell receptor avidity for mycobacterial lipids, leading to in vivo functional diversity during tuberculosis disease., CD4 and CD8 co-receptors are routinely used to define distinct functional and phenotypic lineages of T cells. Here the authors show CD4 and CD8 also modulate the functional avidity of the CD1b-restricted response to mycobacterial lipid antigens

Background Primary cutaneous gamma/delta T-cell lymphoma is aggressive, frequently presenting as multiple plaques, tumors, and/or subcutaneous nodules. Methods In this study, we conducted a retrospective study in a tertiary center in Taiwan to characterize this rare tumor. Results We identified six patients. Five presented with a solitary lesion, including two with clinical impression of epidermal inclusion cyst or lipoma. Two of four evaluable cases exhibited epidermotropism, with one mimicking Pautrier's microabscess. The neoplastic cells were pleomorphic and mostly medium to large-sized. In all cases, the neoplastic cells expressed TCR-γ and/or TCR-δ, with four coexpressing βF1. Two of these βF1+ cases co-expressed TCR-γ, but not TCR-δ (two different clones). All were negative for EBV, low stage, and treated with radiotherapy alone or combined chemotherapy and radiotherapy. In two patients, lymphoma relapsed in 3 and 7 months, respectively, with one patient died of the disease in 7 months. Four other patients were free of disease for 6-126 months. Conclusion PCGD-TCL cases in Taiwan are more commonly solitary, frequently with indolent courses. The two currently available TCR-δ clones alone might be insufficient to detect all tumors. This article is protected by copyright. All rights reserved.

Leptospirosis is one of the neglected diseases caused by the spirochete, Leptospira interrogans. Leptospiral surface adhesion (Lsa) proteins are surface exposed outer membrane proteins present in the pathogen. It acts as laminin and plasminogen binding proteins which enable them to infect host cells. The major target for the development of vaccine in the current era focuses on surface exposed outer membrane proteins, as they can induce strong and fast immune response in hosts. Therefore, the present study mapped the potential epitopes of the Leptospiral outer membrane proteins, mainly the surface adhesion proteins. Protein sequence analysis of Lsa proteins was done by in silico methods. The primary protein sequence analysis revealed Lsa46 as a suitable target which can be a potent Leptospiral vaccine candidate. Its structure was modelled by threading based method in I-TASSER server and validated by Ramachandran plot. The predicted epitope's interactions with human IgG, IgM(Fab) and T-cell receptor TCR(αβ) were performed by molecular docking studies using Biovia Discovery studio 2018. One of the predicted B-cell epitopes and the IgG showed desirable binding interactions, while four of the predicted B-cell epitopes and T-cell epitopes showed desirable binding interactions with IgM and TCR respectively. The molecular dynamic simulation studies carried out with the molecular docked complexes gave minimized energies indicating stable interactions. The structural analysis of the entire simulated complex showed a stable nature except for one of the Epitope-IgM complex. Further the binding free energy calculation of eight receptor-ligand complex predicted them energetically stable. The results of the study help in elucidating the structural and functional characterization of Lsa46 for epitope-based vaccine design.Communicated by Ramaswamy H. Sarma.

In the past decades, immunotherapies against cancers made impressive progress. Immunotherapy includes a broad range of interventions that can be separated into two major groups: cell-based immunotherapies, such as adoptive T cell therapies and stem cell therapies, and immunomodulatory molecular therapies such as checkpoint inhibitors and cytokine therapies. Genetic engineering techniques that transduce T cells with a cancer-antigen-specific T cell receptor or chimeric antigen receptor have expanded to other cell types, and further modulation of the cells to enhance cancer targeting properties has been explored. Because cell-based immunotherapies rely on cells migrating to target organs or tissues, there is a growing interest in imaging technologies that non-invasively monitor transferred cells in vivo. Here, we review whole-body imaging methods to assess cell-based immunotherapy using a variety of examples. Following a review of preclinically used cell tracking technologies, we consider the status of their clinical translation.

Purpose: Gliomas are intrinsic brain tumors with a high degree of constitutive and acquired resistance to standard therapeutic modalities such as radiotherapy and alkylating chemotherapy. Glioma subtypes are recognized by characteristic mutations. Some of these characteristic mutations have shown to generate immunogenic neoepitopes suitable for targeted immunotherapy. Experimental Design: Using peptide-based ELISpot assays, we screened for potential recurrent glioma neoepitopes in MHC-humanized mice. Following vaccination, droplet-based single-cell T-cell receptor (TCR) sequencing from established T-cell lines was applied for neoepitope-specific TCR discovery. Efficacy of intraventricular TCR-transgenic T-cell therapy was assessed in a newly developed glioma model in MHC-humanized mice induced by CRISPR-based delivery of tumor suppressor–targeting guide RNAs. Results: We identify recurrent capicua transcriptional repressor (CIC) inactivating hotspot mutations at position 215 CICR215W/Q as immunogenic MHC class II (MHCII)-restricted neoepitopes. Vaccination of MHC-humanized mice resulted in the generation of robust MHCII-restricted mutation-specific T-cell responses against CICR215W/Q. Adoptive intraventricular transfer of CICR215W-specific TCR-transgenic T cells exert antitumor responses against CICR215W-expressing syngeneic gliomas. Conclusions: The integration of immunocompetent MHC-humanized orthotopic glioma models in the discovery of shared immunogenic glioma neoepitopes facilitates the identification and preclinical testing of human leukocyte antigen (HLA)-restricted neoepitope-specific TCRs for locoregional TCR-transgenic T-cell adoptive therapy.

The identification of patient-specific tumor antigens is complicated by the low frequency of T cells specific for each tumor antigen. Here we describe NeoScreen, a method that enables the sensitive identification of rare tumor (neo)antigens and of cognate T cell receptors (TCRs) expressed by tumor-infiltrating lymphocytes. T cells transduced with tumor antigen-specific TCRs identified by NeoScreen mediate regression of established tumors in patient-derived xenograft mice.

Cytokines play critical roles in regulating iNKT cell development, activation, and maturation. TNF-α co-occurs with iNKT cells in steady-state and many disease conditions. How TNF-α affects iNKT cell function has not been thoroughly investigated. It was found that chronic alcohol consumption enhanced iNKT cell activation and maturation. The underlying mechanism is not known. Herein, a TNF-α KO mouse model was used to address these issues. It was found that the depletion of TNF-α mitigated alcohol consumption-enhanced iNKT cell activation and maturation. In steady-state, depletion of TNF-α did not affect the frequency of iNKT cells in the thymus and spleen but decreased iNKT cells in the liver and increased liver iNKT cell apoptosis. The portion of stage-2 immature iNKT cells increased, stage-3 mature iNKT cells decreased in the thymus of TNF-α KO mice, suggesting that depletion of TNF-α impairs iNKT cell development and maturation. The percentage of CD69+ iNKT cells was significantly lower in the thymus, spleen, and liver of TNF-α KO mice compared to their wild-type littermates, suggesting that depletion of TNF-α inhibits iNKT cell activation. Moreover, the percentage of splenic IL-4- and IFN-γ-producing iNKT cells was significantly lower in TNF-α KO mice than in their wild-type littermates. The depletion of TNF-α increased PLZF+ iNKT cells in the thymus and down-regulated the expression of CD122 on iNKT cells. Collectively, these results support that TNF-α plays a vital role in the regulation of iNKT cell development, activation, and maturation, and alcohol consumption enhances iNKT cell activation and maturation through TNF-α.

Thyristor Controlled Reactor (TCR) has been used to improve power quality through firing angle control by parallel connection to the system in the form of ∆-connection. The inductances of three-phase TCR are assumed to be a same value, but a difference is generated in the inductance value of each phase in the manufacturing process. Due to the difference in three-phase inductance, a conventional TCR control algorithm causes the imbalance of phase voltage. So, this paper proposes a method to solve the phase imbalance problem of TCR using a modified firing angle control scheme, and the performance of the proposed method was verified through Matlab simulation.

The immune cells and the repertoire of T cells and B cells play an important role in the pathogenesis of systemic lupus erythematosus (SLE). Exploring their expression and distribution in SLE can help us better understand this lethal autoimmune disease. In this study, we used a single-cell 5' RNA sequence and single-cell T cell receptor (TCR)/B cell receptor (BCR) to study the immune cells and the repertoire from ten SLE patients and the paired normal controls (NC). The results showed that 9732 cells correspondence to 12 cluster immune cell types were identified in NC, whereas 11042 cells correspondence to 16 cluster immune cell types were identified in SLE. The results demonstrated that neutrophil, macrophage, and dendritic cells were accumulated in SLE by annotating the immune cell types. Besides, the bioinformatics analysis of differentially expressed genes (DEGs) in these cell types indicates their role in inflammation response. In addition, patients with SLE showed increased TCR and BCR clonotypes compared with the healthy controls. Furthermore, patients with SLE showed biased usage of TCR and BCR V(D)J genes. Taken together, we characterized the transcriptome and TCR/BCR immune repertoire profiles of SLE patients, which may provide a new avenue for the diagnosis and treatment of SLE.

Regulatory T cells (Tregs) are essential for the inhibition of immunity and the maintenance of tissue homeostasis. Signals from the T-cell antigen receptor (TCR) are critical for early Treg development, their expansion, and inhibitory activity. Although TCR-engaged activation of the paracaspase MALT1 is important for these Treg activities, the MALT1 effector pathways in Tregs remain ill-defined. Here, we demonstrate that MALT1 protease activity controls the TCR-induced upregulation of the transcription factor MYC and the subsequent expression of MYC target genes in Tregs. These mechanisms are important for Treg-intrinsic mitochondrial function, optimal respiratory capacity, and homeostatic Treg proliferation. Consistently, conditional deletion of Myc in Tregs results similar to MALT1 inactivation in a lethal autoimmune inflammatory syndrome. Together, these results identify a MALT1 protease-mediated link between TCR signaling in Tregs and MYC control that coordinates metabolism and Treg expansion for the maintenance of immune homeostasis.

Small-cell lung cancer (SCLC) is speculated to harbor complex genomic intratumor heterogeneity (ITH) associated with high recurrence rate and suboptimal response to immunotherapy. Here, using multi-region whole exome/T cell receptor (TCR) sequencing as well as immunohistochemistry, we reveal a rather homogeneous mutational landscape but extremely cold and heterogeneous TCR repertoire in limited-stage SCLC tumors (LS-SCLCs). Compared to localized non-small cell lung cancers, LS-SCLCs have similar predicted neoantigen burden and genomic ITH, but significantly colder and more heterogeneous TCR repertoire associated with higher chromosomal copy number aberration (CNA) burden. Furthermore, copy number loss of IFN-γ pathway genes is frequently observed and positively correlates with CNA burden. Higher mutational burden, higher T cell infiltration and positive PD-L1 expression are associated with longer overall survival (OS), while higher CNA burden is associated with shorter OS in patients with LS-SCLC., Small-cell lung cancer (SCLC) is an aggressive disease with limited therapeutic options. Here the authors perform an immunogenomic analysis of limited-stage SCLC, revealing a homogeneous mutational landscape, but limited T-cell infiltration and a cold and heterogeneous T cell repertoire.

Dysfunctional immune activation accumulates during chronic viral infection and contributes to disease pathogenesis. In HIV-1, immune activation is exacerbated by concurrent infection with hepatitis C virus (HCV), accelerating depletion of CD4+ T cells. HIV-1 suppression with antiretroviral therapy (ART) generally reconstitutes CD4+ T cell counts, while also reducing the proportion that is activated. Whether this immune reconstitution also reduces the complexity of the CD4+ T cell population is unknown. We sought to characterize the relationship between activated CD4+ T cell repertoire diversity and immune reconstitution following ART in HIV-1/HCV coinfection. We extracted T cell receptor (TCR) sequences from RNA sequencing data obtained from activated CD4+ T cells of HIV-1/HCV coinfected individuals before and after treatment with ART (clinical trial NCT01285050). There was notable heterogeneity in both the extent of CD4+ T cell reconstitution and in the change in activated CD4+ TCR repertoire diversity following ART. Decreases in activated CD4+ TCR repertoire diversity following ART were predictive of the degree of CD4+ T cell reconstitution. The association of decreased activated CD4+ TCR repertoire diversity and improved CD4+ T cell reconstitution may represent loss of nonspecifically activated TCR clonotypes, and possibly selective expansion of specifically activated CD4+ clones. These results provide insight into the dynamic relationship between activated CD4+ TCR diversity and CD4+ T cell recovery of HIV-1/HCV coinfected individuals after suppression of HIV-1 viremia.

Engineering immune cells to target cancer is a rapidly advancing technology. The first commercial products, chimeric-antigen receptor (CAR) T cells, are now approved for hematologic malignancies. However, solid tumors pose a greater challenge for cellular therapy, in part because suitable cancer-specific antigens are more difficult to identify and surrounding healthy tissues are harder to avoid. In addition, impaired trafficking of immune cells to solid tumors, the harsh immune-inhibitory microenvironment, and variable antigen density and presentation help tumors evade immune cells targeting cancer-specific antigens. To overcome these obstacles, T cells are being engineered to express defined T-cell receptors (TCR). Given that TCRs target intracellular peptides expressed on tumor MHC molecules, this provides an expanded pool of potential targetable tumor-specific antigens relative to the cell-surface antigens that are targeted by CAR T cells. The affinity of TCR T cells can be tuned to allow for better tumor recognition, even with varying levels of antigen presentation on the tumor and surrounding healthy tissue. Further enhancements to TCR T cells include improved platforms that enable more robust cell expansion and persistence; coadministration of small molecules that enhance tumor recognition and immune activation; and coexpression of cytokine-producing moieties, activating coreceptors, or mediators that relieve checkpoint blockade. Early-phase clinical trials pose logistical challenges involving production, large-scale manufacturing, and more. The challenges and obstacles to successful TCR T-cell therapy, and ways to overcome these and improve anticancer activity and efficacy, are discussed herein.

Key Points Diagnosis of TCL often relies on PCR-based TCR clonality testing, which displays low specificity and requires high-quality DNA.Targeted NGS and T-cell clonality assessment are complementary techniques that should be applied in hard front-line diagnosis., Immunomorphological diagnosis of T-cell lymphoma (TCL) may be challenging, especially on needle biopsies. Multiplex polymerase chain reaction (PCR) assays to assess T-cell receptor (TCR) gene rearrangements are now widely used to detect T-cell clones and provide diagnostic support. However, PCR assays detect only 80% of TCL, and clonal lymphocyte populations may also appear in nonneoplastic conditions. More recently, targeted next-generation sequencing (t-NGS) technologies have been deployed to improve lymphoma classification. To the best of our knowledge, the comparison of these techniques’ performance in TCL diagnosis has not been reported yet. In this study, 82 TCL samples and 25 nonneoplastic T-cell infiltrates were divided into 2 cohorts (test and validation) and analyzed with both multiplex PCR and t-NGS to investigate TCR gene rearrangements and somatic mutations, respectively. The detection of mutations appeared to be more specific (100.0%) than T-cell clonality assessment (41.7%-45.5%), whereas no differences were observed in terms of sensitivity (95.1%-97.4%). Furthermore, t-NGS provided a reliable basis for TCL diagnosis in samples with partially degraded DNA that was impossible to assess with PCR. Finally, although multiplex PCR assays appeared to be less specific than t-NGS, both techniques remain complementary, as PCR recovered some t-NGS negative cases.

Circulating CD4+ T cells are dysfunctional in Alzheimer's disease (AD), however, the underlying molecular mechanisms are not clear. In this study, we demonstrate that CD4+ T cells from AD patients and 5xFAD transgenic mice exhibit elevated levels of β-secretase 1 (BACE1). Overexpression of BACE1 in CD4+ T cells potentiated CD4+ T-cell activation and T-cell-dependent immune responses. Mechanistically, BACE1 modulates prostaglandin E2 (PGE2) synthetase-microsomal prostaglandin E synthase 2 (mPGES2)-to promote mPGES2 maturation and PGE2 production, which increases T-cell receptor (TCR) signalling. Moreover, administration of peripheral PGE2 signalling antagonists partially ameliorates CD4+ T cell overactivation and AD pathology in 5xFAD mice. Overall, our results reveal a potential role for BACE1 in mediating CD4+ T-cell dysfunction in AD.

The use of immunotherapy in cancer treatment over the past decade has resulted in significant advances and improvements in cancer patients survival with the use of checkpoint inhibitors. Nevertheless, only a fraction of solid tumors responds to this immunotherapy modality. Another modality of immunotherapy consists of employing cell-based therapy as an adoptive therapeutic modality. That involves distinct modalities of cellular therapies such as CAR T cells (chimeric antigen receptor T cell), TILs (tumor-infiltrating lymphocytes), and TCR T cells. Those treatments have proven effective in hematologic tumors and could have an impact in tumors that do not respond to checkpoint inhibitors. This review aims to outline the rationale, operation, clinical applicability, and results of adoptive cell therapy for patients with solid tumors.

Sputtered Tb/Cr/Fe structures with a Cr layer (tCr) thickness ranging from 0 to 4 nm were prepared. The coercivity (Hc) of Tb/Cr (tCr)/Fe films with tCr ≥ 1 nm is consistent with that of the corresponding Cr(tCr)/Fe films. At the same time, the addition of the Tb layer results in a large saturation magnetization field (Hs) and even oscillatory relations of Hs on tCr, which might indicate an oscillatory indirect exchange coupling mediated by the spin polarization of the spacer Cr layer. Consistent oscillations are observed in anisotropic magnetoresistance (AMR) originating in spin–orbit coupling and magnetoresistance (MR) associated with interlayer exchange coupling as tCr in Tb/Cr/Fe films increases. The oscillatory MR demonstrates antiferromagnetic coupling, which also implies that it is not ordinary MR, although it is of the same magnitude as a result of the nonsharp interfaces. The value of the antiferromagnetic exchange coupling J as a function of tCr is estimated. Consistent oscillations with those in MR and AMR versus tCr are found, accompanied by a gradually flattened oscillation for films with tCr ≥ 2.5 nm resulting from weak coupling as the thick spacer Cr layer. Compared with the curves of MR, AMR, and J versus tCr, the opposite oscillations observed in the curve of Hc/Hs versus tCr further confirm the oscillatory interlayer exchange coupling in the studied structure, which provides theoretical basis for the adjustment of magnetic properties in spintronics by rare earth elements.

It remains largely unclear how thymocytes translate relative differences in T cell receptor (TCR) signal strength into distinct developmental programs that drive the cell fate decisions towards conventional (Tconv) or regulatory T cells (Treg). Following TCR activation, intracellular calcium (Ca2+) is the most important second messenger, for which the potassium channel K2P18.1 is a relevant regulator. Here, we identify K2P18.1 as a central translator of the TCR signal into the thymus-derived Treg (tTreg) selection process. TCR signal was coupled to NF-κB-mediated K2P18.1 upregulation in tTreg progenitors. K2P18.1 provided the driving force for sustained Ca2+ influx that facilitated NF-κB- and NFAT-dependent expression of FoxP3, the master transcription factor for Treg development and function. Loss of K2P18.1 ion-current function induced a mild lymphoproliferative phenotype in mice, with reduced Treg numbers that led to aggravated experimental autoimmune encephalomyelitis, while a gain-of-function mutation in K2P18.1 resulted in increased Treg numbers in mice. Our findings in human thymus, recent thymic emigrants and multiple sclerosis patients with a dominant-negative missense K2P18.1 variant that is associated with poor clinical outcomes indicate that K2P18.1 also plays a role in human Treg development. Pharmacological modulation of K2P18.1 specifically modulated Treg numbers in vitro and in vivo. Finally, we identified nitroxoline as a K2P18.1 activator that led to rapid and reversible Treg increase in patients with urinary tract infections. Conclusively, our findings reveal how K2P18.1 translates TCR signals into thymic T cell fate decisions and Treg development, and provide a basis for the therapeutic utilization of Treg in several human disorders.

Purpose of Review We highlight the new clinical entity multisystem inflammatory syndrome in children (MIS-C), the progress in understanding its immunopathogenesis, and compare and contrast the clinical and immunologic features of MIS-C with Kawasaki disease (KD). Recent Findings Studies show immune dysregulation in MIS-C including T lymphocyte depletion and activation, T cell receptor Vbeta skewing, elevated plasmablast frequencies, increased markers of vascular pathology, and decreased numbers and functional profiles of antigen-presenting cells. Summary MIS-C is a late manifestation of infection with SARS-CoV-2 associated with marked immune activation and many potential mechanisms of immunopathogenesis. MIS-C and KD have clinical similarities but are distinct. Myocardial dysfunction with or without mild coronary artery dilation can occur in MIS-C but generally corrects within weeks. In contrast, the coronary arteries are the primary target in KD, and coronary artery sequelae can be lifelong. Supportive care and anti-inflammatory therapy appear to hasten improvement in children with MIS-C, and there is hope that vaccines will prevent its development.

CMV infection is a significant complication after solid organ transplantation. We used single cell TCR αβ sequencing to determine how memory inflation impacts clonality and diversity of the CMV-responsive CD8 and CD4 T cell repertoire in the first year after transplantation in human subjects. We observed CD8 T cell inflation but no changes in clonal diversity, indicating homeostatic stability in clones. In contrast, the CD4 repertoire was diverse and stable over time, with no evidence of CMV-responsive CD4 T cell expansion. We identified shared CDR3 TCR motifs among patients but no public CMV-specific TCRs. Temporal changes in clonality in response to transplantation and in the absence of detectable viral reactivation suggest changes in the repertoire immediately after transplantation followed by an expansion with stable clonal competition that may mediate protection.

Advancement in our understanding of immune cell recognition and emerging cellular engineering technologies during the last decades made active manipulation of the T cell response possible. Synthetic immunology is providing us with an expanding set of composite receptor molecules capable to reprogram immune cell function in a predefined fashion. Since the first prototypes in the late 1980s, the design of chimeric antigen receptors (CARs; T-bodies, immunoreceptors), has followed a clear line of stepwise improvements from antigen-redirected targeting to designed "living factories" delivering transgenic products on demand. Building on basic research and creative clinical exploration, CAR T cell therapy has been achieving spectacular success in the treatment of hematologic malignancies, now beginning to improve the outcome of cancer patients. In this study, we briefly review the history of CARs and outline how the progress in the basic understanding of T cell recognition and of cell engineering technologies made novel therapies possible.

T-cell receptors (TCRs) and B-cell receptors (BCRs) are critical in recognizing antigens and activating the adaptive immune response. Stochastic V(D)J recombination generates massive TCR/BCR repertoire diversity. Single-cell immune profiling with transcriptome analysis allows the high-throughput study of individual TCR/BCR clonotypes and functions under both normal and pathological settings. However, a comprehensive database linking these data is not yet readily available. Here, we present the human Antigen Receptor database (huARdb), a large-scale human single-cell immune profiling database that contains 444 794 high confidence T or B cells (hcT/B cells) with full-length TCR/BCR sequence and transcriptomes from 215 datasets. All datasets were processed in a uniform workflow, including sequence alignment, cell subtype prediction, unsupervised cell clustering, and clonotype definition. We also developed a multi-functional and user-friendly web interface that provides interactive visualization modules for biologists to analyze the transcriptome and TCR/BCR features at the single-cell level. HuARdb is freely available at https://huarc.net/database with functions for data querying, browsing, downloading, and depositing. In conclusion, huARdb is a comprehensive and multi-perspective atlas for human antigen receptors.

Protein arginine methyltransferase (PRMT) 5 is the type 2 methyltransferase catalyzing symmetric dimethylation of arginine. PRMT5 inhibition or deletion in CD4 Th cells reduces TCR engagement-induced IL-2 production and Th cell expansion and confers protection against experimental autoimmune encephalomyelitis, the animal model of multiple sclerosis. However, the mechanisms by which PRMT5 modulates Th cell proliferation are still not completely understood, and neither are the methylation targets in T cells. In this manuscript, we uncover the role of PRMT5 on alternative splicing in activated mouse T cells and identify several targets of PRMT5 symmetric dimethylation involved in splicing. In addition, we find a possible link between PRMT5-mediated alternative splicing of transient receptor potential cation channel subfamily M member 4 (Trpm4) and TCR/NFAT signaling/IL-2 production. This understanding may guide development of drugs targeting these processes to benefit patients with T cell–mediated diseases.

Two quantitative PCR (qPCR)–based methods, for clonal immunoglobulin or T-cell receptor gene (Ig/TCR) rearrangements and for fusion transcripts, are widely used for the measurement of minimal residual disease (MRD) in patients with B-precursor acute lymphoblastic leukemia (ALL). MRD of bone marrow samples from 165 patients carrying the three major fusion transcripts, including 74 BCR-ABL1, 54 ETV6-RUNX1, and 37 TCF3-PBX1, was analyzed by using the two qPCR-based methods. The correlation coefficient of both methods was good for TCF3-PBX1 (R2 = 0.8088) and BCR-ABL1 (R2 = 0.8094) ALL and moderate for ETV6-RUNX1 (R2 = 0.5972). The concordance was perfect for TCF3-PBX1 ALL (97.2%), substantially concordant for ETV6-RUNX1 ALL (87.1%), and only moderate for BCR-ABL1 ALL (70.6%). The discordant MRD, positive for only one method with a difference greater than one log, was found in 4 of 93 samples (4.3%) with ETV6-RUNX1, 31 of 245 samples (12.7%) with BCR-ABL1, and none of TCF3-PBX1 ALL. None of the eight non-transplanted patients with BCR-ABL1-MRD (+)/Ig/TCR-MRD (–) with a median follow-up time of 73.5 months had hematologic relapses. Our study showed an excellent MRD concordance between the two qPCR-based methods in TCF3-PBX1 ALL, whereas qPCR for Ig/TCR is more reliable in BCR-ABL1 ALL.