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1.
Front Immunol ; 15: 1400550, 2024.
Article in English | MEDLINE | ID: mdl-38835756

ABSTRACT

The dog is an important companion animal and also serves as model species for human diseases. Given the central role of T cells in immune responses, a basic understanding of canine conventional T cell receptor (TCR)αß+ T cells, comprising CD4+ single-positive (sp) T helper (Th) and CD8α+ sp cytotoxic T cell subsets, is available. However, characterization of canine non-conventional TCRαß+ CD4+CD8α+ double-positive (dp) and TCRαß+ CD4-CD8α- double-negative (dn) T cells is limited. In this study, we performed a comprehensive analysis of canine dp and dn T cells in comparison with their conventional counterparts. TCRαß+ T cells from peripheral blood of healthy dogs were sorted according to their CD4/CD8α phenotype into four populations (i.e. CD4+ sp, CD8α+ sp, dp, and dn) and selected surface markers, transcription factors and effector molecules were analyzed ex vivo and after in vitro stimulation by RT-qPCR. Novel characteristics of canine dp T cells were identified, expanding the previously characterized Th1-like phenotype to Th17-like and Th2-like properties. Overall, mRNA expression of various Th cell-associated cytokines (i.e. IFNG, IL17A, IL4, IL13) in dp T cells upon stimulation highlights their versatile immunological potential. Furthermore, we demonstrated that the CD4-CD8α- dn phenotype is stable during in vitro stimulation. Strikingly, dn T cells were found to express highest mRNA levels of type 2 effector cytokines (IL4, IL5, and IL13) upon stimulation. Their strong ability to produce IL-4 was confirmed at the protein level. Upon stimulation, the percentage of IL-4-producing cells was even higher in the non-conventional dn than in the conventional CD4+ sp population. Constitutive transcription of IL1RL1 (encoding IL-33Rα) further supports Th2-like properties within the dn T cell population. These data point to a role of dn T cells in type 2 immunity. In addition, the high potential of dn T cells to transcribe the gene encoding the co-inhibitory receptor CTLA-4 and to produce the inhibitory cytokine IL-10 indicates putative immunosuppressive capacity of this population. In summary, this study reveals important novel aspects of canine non-conventional T cells providing the basis for further studies on their effector and/or regulatory functions to elucidate their role in health and disease.


Subject(s)
Receptors, Antigen, T-Cell, alpha-beta , Th2 Cells , Animals , Dogs , Receptors, Antigen, T-Cell, alpha-beta/genetics , Receptors, Antigen, T-Cell, alpha-beta/immunology , Receptors, Antigen, T-Cell, alpha-beta/metabolism , Th2 Cells/immunology , CD8 Antigens/metabolism , CD8 Antigens/immunology , Cytokines/metabolism , CD4 Antigens/metabolism , CD4 Antigens/immunology , T-Lymphocyte Subsets/immunology , T-Lymphocyte Subsets/metabolism , T-Lymphocytes, Regulatory/immunology , T-Lymphocytes, Regulatory/metabolism , Immunophenotyping , Male
2.
Dev Comp Immunol ; 157: 105196, 2024 Aug.
Article in English | MEDLINE | ID: mdl-38762097

ABSTRACT

The thymus-derived lymphocytes of jawed vertebrates have four T-cell receptor (TCR) chains that play a significant role in immunity. As chickens have commercial value, their immune systems require a great deal of attention. Local chicken breeds are an essential part of poultry genetic resources in China. Here, we used high-throughput sequencing to analyze the TCRα and TCRß repertoires and their relative expression levels in the native chicken breeds Baier Buff, Longyou Partridge, Xiaoshan, and Xianju. We found that TCR Vα and TCR Vß were expressed and included 17, 19, 17, and six segments of the Vα2, Vα3, Vß1, and Vß2 subgroups, respectively. V-J pairing was biased; Jα11 was utilized by nearly all Vα segments and was the most commonly used. Breed-specific V segments and V-J pairings were detected as well. The results of the principal coordinate analysis (PCoA) as well as the V-J pairing and CDR3 diversity analyses suggested that the four local chicken breeds did not significantly differ in terms of TCR diversity. Hence, they expressed not significant differentiation, and they are rich genetic resources for the development and utilization of immune-related poultry breeding.


Subject(s)
Chickens , Receptors, Antigen, T-Cell, alpha-beta , Animals , Chickens/immunology , Chickens/genetics , Receptors, Antigen, T-Cell, alpha-beta/genetics , Receptors, Antigen, T-Cell, alpha-beta/metabolism , High-Throughput Nucleotide Sequencing , Breeding , Genetic Variation , China , Complementarity Determining Regions/genetics
3.
Autoimmunity ; 57(1): 2347379, 2024 Apr 27.
Article in English | MEDLINE | ID: mdl-38723105

ABSTRACT

Thymoma is closely associated with myasthenia gravis (MG). However, due to the heterogeneity of thymoma and the intricate pathogenesis of MG, it remains unclear why some patients with thymoma develop MG and others do not. In this study, we conducted a comparative phenotype analysis of thymocytes in type B thymomas in patients with MG (MG (+) thymomas) and without MG (MG (-) thymomas) via fluorescence-activated cell sorting (FACS). Our results show that the developmental stages defined by the expression of CD3, CD4, and CD8 were largely maintained in both MG (+) and MG (-) thymomas, with CD4+CD8+ cells constituting the majority of thymocytes in type B thymoma, and no significant difference between this cell population was observed in MG (+) and MG (-) thymomas.We discovered that CD4+CD8+ thymocytes in MG (+) thymomas expressed low levels of αß TCR and high levels of IL-7 receptor α (IL-7Rα), whereas in MG (-) thymomas, CD4+CD8+ thymocytes exhibited the opposite pattern of αß TCR and IL-7Rα expression. These results suggest that the positive and negative selection processes of CD4+CD8+ thymocytes might differ between MG (+) thymomas and MG (-) thymomas. The expression of the Helios transcription factor is induced during negative selection and marks a group of T cells that have undergone negative selection and are likely to be deleted due to strong TCR binding with self-peptides/MHC ligands. We observed that the percentage of Helios-positive CD4SP T cells was greater in MG (-) than in MG (+) thymomas. Thus, the differentially regulated selection process of CD4+CD8+ thymocytes, which involves TCR and IL-7/IL-7Rα signaling, is associated with the presence of MG in type B thymomas.


Subject(s)
Myasthenia Gravis , Receptors, Antigen, T-Cell, alpha-beta , Thymocytes , Thymoma , Humans , Thymoma/immunology , Thymoma/pathology , Thymoma/metabolism , Myasthenia Gravis/immunology , Myasthenia Gravis/pathology , Myasthenia Gravis/metabolism , Receptors, Antigen, T-Cell, alpha-beta/metabolism , Male , Thymocytes/immunology , Thymocytes/metabolism , Female , Middle Aged , Receptors, Interleukin-7/metabolism , Receptors, Interleukin-7/immunology , Adult , Aged , Thymus Neoplasms/immunology , Thymus Neoplasms/pathology , Thymus Neoplasms/metabolism , CD4-Positive T-Lymphocytes/immunology , CD4-Positive T-Lymphocytes/metabolism , CD8-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/metabolism , Immunophenotyping
4.
Nat Commun ; 15(1): 4227, 2024 May 18.
Article in English | MEDLINE | ID: mdl-38762592

ABSTRACT

Multisystem inflammatory syndrome in children is a post-infectious presentation SARS-CoV-2 associated with expansion of the T cell receptor Vß21.3+ T-cell subgroup. Here we apply muti-single cell omics to compare the inflammatory process in children with acute respiratory COVID-19 and those presenting with non SARS-CoV-2 infections in children. Here we show that in Multi-Inflammatory Syndrome in Children (MIS-C), the natural killer cell and monocyte population demonstrate heightened CD95 (Fas) and Interleuking 18 receptor expression. Additionally, TCR Vß21.3+ CD4+ T-cells exhibit skewed differentiation towards T helper 1, 17 and regulatory T cells, with increased expression of the co-stimulation receptors ICOS, CD28 and interleukin 18 receptor. We observe no functional evidence for NLRP3 inflammasome pathway overactivation, though MIS-C monocytes show elevated active caspase 8. This, coupled with raised IL18 mRNA expression in CD16- NK cells on single cell RNA sequencing analysis, suggests interleukin 18 and CD95 signalling may trigger activation of TCR Vß21.3+ T-cells in MIS-C, driven by increased IL-18 production from activated monocytes and CD16- Natural Killer cells.


Subject(s)
COVID-19 , Interleukin-18 , Killer Cells, Natural , Monocytes , Signal Transduction , Systemic Inflammatory Response Syndrome , fas Receptor , Humans , Interleukin-18/metabolism , Child , Killer Cells, Natural/immunology , Killer Cells, Natural/metabolism , fas Receptor/metabolism , fas Receptor/genetics , Monocytes/immunology , Monocytes/metabolism , Systemic Inflammatory Response Syndrome/immunology , Systemic Inflammatory Response Syndrome/metabolism , COVID-19/immunology , COVID-19/virology , COVID-19/metabolism , COVID-19/complications , Inflammasomes/metabolism , Inflammasomes/immunology , SARS-CoV-2/immunology , Adolescent , Male , Receptors, Antigen, T-Cell, alpha-beta/metabolism , Receptors, Antigen, T-Cell, alpha-beta/genetics , Female , Child, Preschool , Single-Cell Analysis , NLR Family, Pyrin Domain-Containing 3 Protein/metabolism , NLR Family, Pyrin Domain-Containing 3 Protein/genetics , CD4-Positive T-Lymphocytes/immunology , CD4-Positive T-Lymphocytes/metabolism , CD28 Antigens/metabolism , Lymphocyte Activation/immunology , Receptors, Interleukin-18/metabolism , Receptors, Interleukin-18/genetics , Receptors, Interleukin-18/immunology
5.
PLoS One ; 19(4): e0301175, 2024.
Article in English | MEDLINE | ID: mdl-38574067

ABSTRACT

BACKGROUND: Canonical α/ß T-cell receptors (TCRs) bind to human leukocyte antigen (HLA) displaying antigenic peptides to elicit T cell-mediated cytotoxicity. TCR-engineered T-cell immunotherapies targeting cancer-specific peptide-HLA complexes (pHLA) are generating exciting clinical responses, but owing to HLA restriction they are only able to target a subset of antigen-positive patients. More recently, evidence has been published indicating that naturally occurring α/ß TCRs can target cell surface proteins other than pHLA, which would address the challenges of HLA restriction. In this proof-of-concept study, we sought to identify and engineer so-called HLA-independent TCRs (HiTs) against the tumor-associated antigen mesothelin. METHODS: Using phage display, we identified a HiT that bound well to mesothelin, which when expressed in primary T cells, caused activation and cytotoxicity. We subsequently engineered this HiT to modulate the T-cell response to varying levels of mesothelin on the cell surface. RESULTS: The isolated HiT shows cytotoxic activity and demonstrates killing of both mesothelin-expressing cell lines and patient-derived xenograft models. Additionally, we demonstrated that HiT-transduced T cells do not require CD4 or CD8 co-receptors and, unlike a TCR fusion construct, are not inhibited by soluble mesothelin. Finally, we showed that HiT-transduced T cells are highly efficacious in vivo, completely eradicating xenografted human solid tumors. CONCLUSION: HiTs can be isolated from fully human TCR-displaying phage libraries against cell surface-expressed antigens. HiTs are able to fully activate primary T cells both in vivo and in vitro. HiTs may enable the efficacy seen with pHLA-targeting TCRs in solid tumors to be translated to cell surface antigens.


Subject(s)
Mesothelin , Neoplasms , Humans , CD8-Positive T-Lymphocytes , Receptors, Antigen, T-Cell , Antigens, Neoplasm/metabolism , Neoplasms/metabolism , Receptors, Antigen, T-Cell, alpha-beta/metabolism , HLA Antigens/metabolism , Histocompatibility Antigens Class II/metabolism , Peptides/metabolism , Histocompatibility Antigens/metabolism
6.
Oncoimmunology ; 13(1): 2345859, 2024.
Article in English | MEDLINE | ID: mdl-38686178

ABSTRACT

Immune checkpoint therapy (ICT) causes durable tumour responses in a subgroup of patients, but it is not well known how T cell receptor beta (TCRß) repertoire dynamics contribute to the therapeutic response. Using murine models that exclude variation in host genetics, environmental factors and tumour mutation burden, limiting variation between animals to naturally diverse TCRß repertoires, we applied TCRseq, single cell RNAseq and flow cytometry to study TCRß repertoire dynamics in ICT responders and non-responders. Increased oligoclonal expansion of TCRß clonotypes was observed in responding tumours. Machine learning identified TCRß CDR3 signatures unique to each tumour model, and signatures associated with ICT response at various timepoints before or during ICT. Clonally expanded CD8+ T cells in responding tumours post ICT displayed effector T cell gene signatures and phenotype. An early burst of clonal expansion during ICT is associated with response, and we report unique dynamics in TCRß signatures associated with ICT response.


Subject(s)
Immune Checkpoint Inhibitors , Lymphocytes, Tumor-Infiltrating , Receptors, Antigen, T-Cell, alpha-beta , Animals , Immune Checkpoint Inhibitors/pharmacology , Immune Checkpoint Inhibitors/therapeutic use , Receptors, Antigen, T-Cell, alpha-beta/genetics , Receptors, Antigen, T-Cell, alpha-beta/metabolism , Mice , Lymphocytes, Tumor-Infiltrating/immunology , Lymphocytes, Tumor-Infiltrating/drug effects , Lymphocytes, Tumor-Infiltrating/metabolism , CD8-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/drug effects , CD8-Positive T-Lymphocytes/metabolism , Humans , Mice, Inbred C57BL , Female
7.
Hum Immunol ; 85(3): 110795, 2024 May.
Article in English | MEDLINE | ID: mdl-38582657

ABSTRACT

The coronavirus disease 2019 (COVID-19) has merged as a global health threat since its outbreak in December 2019. Despite widespread recognition, there has been a paucity of studies focusing on the T cell receptor (TCR) bias in adaptive immunity induced by SARS-CoV-2. This research conducted a comparative analysis of the TCR immune repertoire to identify notable αß TCR bias sequences associated with the SARS-CoV-2 virus antigen. The present study encompassed 73 symptomatic COVID-19 patients, categorized as moderate/mild or severe/critical, along with 9 healthy controls. Our findings revealed specific TCR chains prominently utilized by moderate and severe patients, identified as TRAV30-J34-TRBV3-1-J2-7 and TRAV12-3-J6-TRBV28-J1-1, respectively. Additionally, our research explored critical TCR preferences in the bronchoalveolar lavage fluid (BALF) of COVID-19 patients at various disease stages. Indeed, monitoring the dynamics of immune repertoire changes in COVID-19 patients could serve as a crucial biomarker for predicting disease progression and recovery. Furthermore, the study explored TCR bias in both peripheral blood mononuclear cells (PBMCs) and BALF. The most common αß VJ pair observed in BALF was TRAV12-3-J18-TRBV7-6-J2-7. In addition, a comparative analysis with the VDJdb database indicated that the HLA-A*02:01 allele exhibited the widest distribution and highest frequency in COVID-19 patients across different periods. This comprehensive examination provided a global characterization of the TCR immune repertoire in COVID-19 patients, contributing significantly to our understanding of TCR bias induced by SARS-CoV-2.


Subject(s)
COVID-19 , Receptors, Antigen, T-Cell, alpha-beta , SARS-CoV-2 , Humans , COVID-19/immunology , SARS-CoV-2/immunology , Male , Female , Middle Aged , Receptors, Antigen, T-Cell, alpha-beta/genetics , Receptors, Antigen, T-Cell, alpha-beta/immunology , Receptors, Antigen, T-Cell, alpha-beta/metabolism , Adult , Bronchoalveolar Lavage Fluid/immunology , Aged , Receptors, Antigen, T-Cell/immunology , Receptors, Antigen, T-Cell/genetics , Receptors, Antigen, T-Cell/metabolism , Adaptive Immunity/immunology , Severity of Illness Index
8.
J Immunol ; 212(11): 1843-1854, 2024 Jun 01.
Article in English | MEDLINE | ID: mdl-38568091

ABSTRACT

Intraepithelial lymphocytes (IELs) are T cells important for the maintenance of barrier integrity in the intestine. Colon IELs are significantly reduced in both MyD88-deficient mice and those lacking an intact microbiota, suggesting that MyD88-mediated detection of bacterial products is important for the recruitment and/or retention of these cells. Here, using conditionally deficient MyD88 mice, we show that myeloid cells are the key mediators of TCRαß+ IEL recruitment to the colon. Upon exposure to luminal bacteria, myeloid cells produce sphingosine-1-phosphate (S1P) in a MyD88-dependent fashion. TCRαß+ IEL recruitment may be blocked using the S1P receptor antagonist FTY720, confirming the importance of S1P in the recruitment of TCRαß+ IELs to the colon epithelium. Finally, using the TNFΔARE/+ model of Crohn's-like bowel inflammation, we show that disruption of colon IEL recruitment through myeloid-specific MyD88 deficiency results in reduced pathology. Our results illustrate one mechanism for recruitment of a subset of IELs to the colon.


Subject(s)
Colon , Intestinal Mucosa , Intraepithelial Lymphocytes , Lysophospholipids , Mice, Knockout , Myeloid Cells , Myeloid Differentiation Factor 88 , Receptors, Antigen, T-Cell, alpha-beta , Sphingosine , Animals , Lysophospholipids/metabolism , Mice , Sphingosine/analogs & derivatives , Sphingosine/metabolism , Colon/immunology , Myeloid Differentiation Factor 88/metabolism , Myeloid Cells/immunology , Myeloid Cells/metabolism , Intestinal Mucosa/immunology , Intestinal Mucosa/metabolism , Intraepithelial Lymphocytes/immunology , Intraepithelial Lymphocytes/metabolism , Receptors, Antigen, T-Cell, alpha-beta/metabolism , Receptors, Antigen, T-Cell, alpha-beta/genetics , Mice, Inbred C57BL , Fingolimod Hydrochloride/pharmacology , Crohn Disease/immunology
9.
J Med Chem ; 67(9): 7635-7646, 2024 May 09.
Article in English | MEDLINE | ID: mdl-38661304

ABSTRACT

The T-cell receptor (TCR) is a crucial molecule in cellular immunity. The single-chain T-cell receptor (scTCR) is a potential format in TCR therapeutics because it eliminates the possibility of αß-TCR mispairing. However, its poor stability and solubility impede the in vitro study and manufacturing of therapeutic applications. In this study, some conserved structural motifs are identified in variable domains regardless of germlines and species. Theoretical analysis helps to identify those unfavored factors and leads to a general strategy for stabilizing scTCRs by substituting residues at exact IMGT positions with beneficial propensities on the consensus sequence of germlines. Several representative scTCRs are displayed to achieve stability optimization and retain comparable binding affinities with the corresponding αß-TCRs in the range of µM to pM. These results demonstrate that our strategies for scTCR engineering are capable of providing the affinity-enhanced and specificity-retained format, which are of great value in facilitating the development of TCR-related therapeutics.


Subject(s)
Receptors, Antigen, T-Cell , Humans , Receptors, Antigen, T-Cell/chemistry , Receptors, Antigen, T-Cell/metabolism , Receptors, Antigen, T-Cell/immunology , Protein Stability , Receptors, Antigen, T-Cell, alpha-beta/chemistry , Receptors, Antigen, T-Cell, alpha-beta/metabolism , Amino Acid Sequence , Models, Molecular , Protein Engineering , Protein Binding
10.
Fish Shellfish Immunol ; 148: 109475, 2024 May.
Article in English | MEDLINE | ID: mdl-38447781

ABSTRACT

The T-cell receptor (TCR) is a specific molecule on the surface of all T cells that mediates cellular adaptive immune responses to antigens. Hucho bleekeri is a critically endangered species and is regarded as a glacial relict that has the lowest-latitude distribution compared with any Eurasian salmonid. In the present study, two TCR genes, namely, TCR α and ß, were identified and characterized in H. bleekeri. Both TCR α and TCR ß have typical TCR structures, including the IgV domain, IgC domain, connecting peptide, transmembrane and cytoplasmic domains. The two TCR genes were constitutionally expressed in various tissues, with the highest expression found in the spleen for TCR α and in the trunk kidney for TCR ß. Challenge of H. bleekeri with LPS or poly(I:C) resulted in significant upregulation of both TCR α and ß expression in headkidney and spleen primary cells, indicating their potential roles in the immune response. Molecular polymorphism analysis of the whole ORF regions of TCR α and ß in different individuals revealed high diversity of IgV domains of these two genes, especially in complementarity-determining region (CDR) 3. The ratio of nonsynonymous substitution occurred at a significantly higher frequency than synonymous substitution in the CDR of TCR α and ß, demonstrating the existence of positive selection. The results obtained in the present study enhance our understanding of TCR roles in regulating immune mechanisms and provide new information for the study of TCR lineage diversity in fish.


Subject(s)
Receptors, Antigen, T-Cell, alpha-beta , Salmonidae , Animals , Receptors, Antigen, T-Cell, alpha-beta/genetics , Receptors, Antigen, T-Cell, alpha-beta/metabolism , Polymorphism, Genetic , T-Lymphocytes , Receptors, Antigen, T-Cell/genetics , Salmonidae/genetics
11.
Arterioscler Thromb Vasc Biol ; 44(6): 1302-1314, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38511327

ABSTRACT

INTRODUCTION: Viral infections have been associated with the progression of atherosclerosis and CD8+ T-cells directed against common viruses, such as influenza, Epstein-Barr virus, and cytomegalovirus, have been detected inside human atherosclerotic lesions. These virus-specific CD8+ T-cells have been hypothesized to contribute to the development of atherosclerosis; however, whether they affect disease progression directly remains unclear. In this study, we aimed to characterize the activation status of virus-specific CD8+ T-cells in the atherosclerotic lesion. METHODS: The presence, clonality, tissue enrichment, and phenotype of virus-associated CD8+ T-cells in atherosclerotic lesions were assessed by exploiting bulk T-cell receptor-ß sequencing and single-cell T-cell receptor (α and ß) sequencing datasets on human endarterectomy samples and patient-matched blood samples. To investigate if virus-specific CD8+ T-cells can be activated through T-cell receptor stimulation in the atherosclerotic lesion, the immunopeptidome of human plaques was determined. RESULTS: Virus-associated CD8+ T-cells accumulated more in the atherosclerotic lesion (mean=2.0%), compared with patient-matched blood samples (mean=1.4%; P=0.05), and were more clonally expanded and tissue enriched in the atherosclerotic lesion in comparison with nonassociated CD8+ T-cells from the lesion. Single-cell T-cell receptor sequencing and flow cytometry revealed that these virus-associated CD8+ T-cells were phenotypically highly similar to other CD8+ T-cells in the lesion and that both exhibited a more activated phenotype compared with circulating T-cells. Interestingly, virus-associated CD8+ T-cells are unlikely to be activated through antigen-specific interactions in the atherosclerotic lesion, as no virus-derived peptides were detected on HLA-I in the lesion. CONCLUSIONS: This study suggests that virus-specific CD8+ T-cells are tissue enriched in atherosclerotic lesions; however, their potential contribution to inflammation may involve antigen-independent mechanisms.


Subject(s)
CD8-Positive T-Lymphocytes , Lymphocyte Activation , Plaque, Atherosclerotic , Humans , CD8-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/virology , Atherosclerosis/immunology , Atherosclerosis/virology , Atherosclerosis/pathology , Male , Phenotype , Receptors, Antigen, T-Cell, alpha-beta/genetics , Receptors, Antigen, T-Cell, alpha-beta/metabolism , Receptors, Antigen, T-Cell, alpha-beta/immunology , Female , Middle Aged , Aged , Carotid Artery Diseases/immunology , Carotid Artery Diseases/virology , Carotid Artery Diseases/pathology , Host-Pathogen Interactions
13.
Trends Immunol ; 45(4): 288-302, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38514370

ABSTRACT

The mammalian small intestine epithelium harbors a peculiar population of CD4+CD8αα+ T cells that are derived from mature CD4+ T cells through reprogramming of lineage-specific transcription factors. CD4+CD8αα+ T cells occupy a unique niche in T cell biology because they exhibit mixed phenotypes and functional characteristics of both CD4+ helper and CD8+ cytotoxic T cells. The molecular pathways driving their generation are not fully mapped. However, recent studies demonstrate the unique role of the commensal gut microbiota as well as distinct cytokine and chemokine requirements in the differentiation and survival of these cells. We review the established and newly identified factors involved in the generation of CD4+CD8αα+ intraepithelial lymphocytes (IELs) and place them in the context of the molecular machinery that drives their phenotypic and functional differentiation.


Subject(s)
Intraepithelial Lymphocytes , Humans , Animals , Cell Differentiation , Transcription Factors/metabolism , T-Lymphocytes, Cytotoxic , CD8-Positive T-Lymphocytes , Intestinal Mucosa/metabolism , Receptors, Antigen, T-Cell, alpha-beta/metabolism , Mammals
14.
Sci Immunol ; 9(92): eadk4348, 2024 09 02.
Article in English | MEDLINE | ID: mdl-38335269

ABSTRACT

TCRαß+CD8αα+ intraepithelial lymphocytes (CD8αα+ αß IELs) are a specialized subset of T cells in the gut epithelium that develop from thymic agonist selected IEL precursors (IELps). The molecular mechanisms underlying the selection and differentiation of this T cell type in the thymus are largely unknown. Here, we found that Bcl6 deficiency in αß T cells resulted in the near absence of CD8αα+ αß IELs. BCL6 was expressed by approximately 50% of CD8αα+ αß IELs and by the majority of thymic PD1+ IELps after agonist selection. Bcl6 deficiency blocked early IELp generation in the thymus, and its expression in IELps was induced by thymic TCR signaling in an ERK-dependent manner. As a result of Bcl6 deficiency, the precursors of IELps among CD4+CD8+ double-positive thymocytes exhibited increased apoptosis during agonist selection and impaired IELp differentiation and maturation. Together, our results elucidate BCL6 as a crucial transcription factor during the thymic development of CD8αα+ αß IELs.


Subject(s)
Intraepithelial Lymphocytes , Proto-Oncogene Proteins c-bcl-6 , Receptors, Antigen, T-Cell, alpha-beta , Animals , Mice , CD8 Antigens/metabolism , CD8-Positive T-Lymphocytes/metabolism , Intestinal Mucosa , Intraepithelial Lymphocytes/metabolism , Mice, Knockout , Receptors, Antigen, T-Cell, alpha-beta/genetics , Receptors, Antigen, T-Cell, alpha-beta/metabolism , Proto-Oncogene Proteins c-bcl-6/metabolism
15.
J Immunol ; 212(6): 933-940, 2024 Mar 15.
Article in English | MEDLINE | ID: mdl-38275935

ABSTRACT

In response to microbial infection, the nonclassical Ag-presenting molecule MHC class I-related protein 1 (MR1) presents secondary microbial metabolites to mucosal-associated invariant T (MAIT) cells. In this study, we further characterize the repertoire of ligands captured by MR1 produced in Hi5 (Trichoplusia ni) cells from Mycobacterium smegmatis via mass spectrometry. We describe the (to our knowledge) novel MR1 ligand photolumazine (PL)V, a hydroxyindolyl-ribityllumazine with four isomers differing in the positioning of a hydroxyl group. We show that all four isomers are produced by M. smegmatis in culture and that at least three can induce MR1 surface translocation. Furthermore, human MAIT cell clones expressing distinct TCR ß-chains differentially responded to the PLV isomers, demonstrating that the subtle positioning of a single hydroxyl group modulates TCR recognition. This study emphasizes structural microheterogeneity within the MR1 Ag repertoire and the remarkable selectivity of MAIT cell TCRs.


Subject(s)
Mucosal-Associated Invariant T Cells , Humans , Receptors, Antigen, T-Cell, alpha-beta/metabolism , Minor Histocompatibility Antigens , Histocompatibility Antigens Class I/metabolism , Receptors, Antigen, T-Cell/metabolism
16.
Elife ; 132024 Jan 03.
Article in English | MEDLINE | ID: mdl-38167271

ABSTRACT

Mechanical force is critical for the interaction between an αß T cell receptor (TCR) and a peptide-bound major histocompatibility complex (pMHC) molecule to initiate productive T-cell activation. However, the underlying mechanism remains unclear. We use all-atom molecular dynamics simulations to examine the A6 TCR bound to HLA-A*02:01 presenting agonist or antagonist peptides under different extensions to simulate the effects of applied load on the complex, elucidating their divergent biological responses. We found that TCR α and ß chains move asymmetrically, which impacts the interface with pMHC, in particular the peptide-sensing CDR3 loops. For the wild-type agonist, the complex stabilizes in a load-dependent manner while antagonists destabilize it. Simulations of the Cß FG-loop deletion, which reduces the catch bond response, and simulations with in silico mutant peptides further support the observed behaviors. The present results highlight the combined role of interdomain motion, fluctuating forces, and interfacial contacts in determining the mechanical response and fine peptide discrimination by a TCR, thereby resolving the conundrum of nearly identical crystal structures of TCRαß-pMHC agonist and antagonist complexes.


Subject(s)
Peptides , Receptors, Antigen, T-Cell, alpha-beta , Receptors, Antigen, T-Cell, alpha-beta/metabolism , Protein Binding , Peptides/metabolism , Receptors, Antigen, T-Cell/metabolism , Molecular Dynamics Simulation , Major Histocompatibility Complex , Histocompatibility Antigens/metabolism
17.
Cancer Immunol Immunother ; 73(2): 24, 2024 Jan 27.
Article in English | MEDLINE | ID: mdl-38280010

ABSTRACT

Tumor-infiltrating lymphocytes (TILs) play a key role in regulating the host immune response and shaping tumor microenvironment. It has been previously shown that T cell infiltration in penile tumors was associated with clinical outcomes. However, few studies have reported the T cell receptor (TCR) repertoire in patients with penile cancer. In the present study, we evaluated the TCR repertoires in tumor and adjacent normal tissues from 22 patients with penile squamous cell carcinoma (PSCC). Analysis of the T cell receptor beta-variable (TRBV) and joining (TRBJ) genes usage and analysis of complementarity determining region 3 (CDR3) length distribution did not show significant differences between tumor and matched normal tissues. Moreover, analysis of the median Jaccard index indicated a limited overlap of TCR repertoire between these groups. Compared with normal tissues, a significantly lower diversity and higher clonality of TCR repertoire was observed in tumor samples, which was associated with clinical characteristics. Further analysis of transcriptional profiles demonstrated that tumor samples with high clonality showed increased expression of genes associated with CD8 + T cells. In addition, we analyzed the TCR repertoire of CD4 + T cells and CD8 + T cells isolated from tumor tissues. We identified that expanded clonotypes were predominantly in the CD8 + T cell compartment, which presented with an exhausted phenotype. Overall, we comprehensively compared TCR repertoire between penile tumor and normal tissues and demonstrated the presence of distinct T cell immune microenvironments in patients with PSCC.


Subject(s)
Carcinoma, Squamous Cell , Penile Neoplasms , Male , Humans , Receptors, Antigen, T-Cell , Penile Neoplasms/genetics , Penile Neoplasms/metabolism , Complementarity Determining Regions/metabolism , Receptors, Antigen, T-Cell, alpha-beta/metabolism , CD8-Positive T-Lymphocytes , Carcinoma, Squamous Cell/genetics , Carcinoma, Squamous Cell/metabolism , Tumor Microenvironment
18.
Front Immunol ; 14: 1250316, 2023.
Article in English | MEDLINE | ID: mdl-38022509

ABSTRACT

MHC-E restricted CD8 T cells show promise in vaccine settings, but their development and specificity remain poorly understood. Here we focus on a CD8 T cell population reactive to a self-peptide (FL9) bound to mouse MHC-E (Qa-1b) that is presented in response to loss of the MHC I processing enzyme ERAAP, termed QFL T cells. We find that mature QFL thymocytes are predominantly CD8αß+CD4-, show signs of agonist selection, and give rise to both CD8αα and CD8αß intraepithelial lymphocytes (IEL), as well as memory phenotype CD8αß T cells. QFL T cells require the MHC I subunit ß-2 microglobulin (ß2m), but do not require Qa1b or classical MHC I for positive selection. However, QFL thymocytes do require Qa1b for agonist selection and full functionality. Our data highlight the relaxed requirements for positive selection of an MHC-E restricted T cell population and suggest a CD8αß+CD4- pathway for development of CD8αα IELs.


Subject(s)
CD8-Positive T-Lymphocytes , Receptors, Antigen, T-Cell, alpha-beta , Animals , Mice , Peptides/metabolism , Receptors, Antigen, T-Cell, alpha-beta/genetics , Receptors, Antigen, T-Cell, alpha-beta/metabolism , Thymocytes/metabolism , Genes, MHC Class II
19.
Sci Transl Med ; 15(724): eadi0258, 2023 11 29.
Article in English | MEDLINE | ID: mdl-38019931

ABSTRACT

Despite the success of programmed cell death-1 (PD-1) and PD-1 ligand (PD-L1) inhibitors in treating solid tumors, only a proportion of patients respond. Here, we describe a first-in-class bifunctional therapeutic molecule, STAR0602, that comprises an antibody targeting germline Vß6 and Vß10 T cell receptors (TCRs) fused to human interleukin-2 (IL-2) and simultaneously engages a nonclonal mode of TCR activation with costimulation to promote activation and expansion of αß T cell subsets expressing distinct variable ß (Vß) TCR chains. In solution, STAR0602 binds IL-2 receptors in cis with Vß6/Vß10 TCRs on the same T cell, promoting expansion of human Vß6 and Vß10 CD4+ and CD8+ T cells that acquire an atypical central memory phenotype. Monotherapy with a mouse surrogate molecule induced durable tumor regression across six murine solid tumor models, including several refractory to anti-PD-1. Analysis of murine tumor-infiltrating lymphocyte (TIL) transcriptomes revealed that expanded Vß T cells acquired a distinct effector memory phenotype with suppression of genes associated with T cell exhaustion and TCR signaling repression. Sequencing of TIL TCRs also revealed an increased T cell repertoire diversity within targeted Vß T cell subsets, suggesting clonal revival of tumor T cell responses. These immunological and antitumor effects in mice were recapitulated in studies of STAR0602 in nonhuman primates and human ex vivo models, wherein STAR0602 boosted human antigen-specific T cell responses and killing of tumor organoids. Thus, STAR0602 represents a distinct class of T cell-activating molecules with the potential to deliver enhanced antitumor activity in checkpoint inhibitor-refractory settings.


Subject(s)
Neoplasms , Receptors, Antigen, T-Cell, alpha-beta , Humans , Animals , Mice , Receptors, Antigen, T-Cell, alpha-beta/metabolism , CD8-Positive T-Lymphocytes , Programmed Cell Death 1 Receptor/metabolism , Receptors, Antigen, T-Cell/metabolism , Neoplasms/drug therapy , Neoplasms/metabolism , Antibodies/pharmacology
20.
Sci Rep ; 13(1): 20888, 2023 11 28.
Article in English | MEDLINE | ID: mdl-38017015

ABSTRACT

T cells are important in the pathogenesis of acute kidney injury (AKI), and TCR+CD4-CD8- (double negative-DN) are T cells that have regulatory properties. However, there is limited information on DN T cells compared to traditional CD4+ and CD8+ cells. To elucidate the molecular signature and spatial dynamics of DN T cells during AKI, we performed single-cell RNA sequencing (scRNA-seq) on sorted murine DN, CD4+, and CD8+ cells combined with spatial transcriptomic profiling of normal and post AKI mouse kidneys. scRNA-seq revealed distinct transcriptional profiles for DN, CD4+, and CD8+ T cells of mouse kidneys with enrichment of Kcnq5, Klrb1c, Fcer1g, and Klre1 expression in DN T cells compared to CD4+ and CD8+ T cells in normal kidney tissue. We validated the expression of these four genes in mouse kidney DN, CD4+ and CD8+ T cells using RT-PCR and Kcnq5, Klrb1, and Fcer1g genes with the NIH human kidney precision medicine project (KPMP). Spatial transcriptomics in normal and ischemic mouse kidney tissue showed a localized cluster of T cells in the outer medulla expressing DN T cell genes including Fcer1g. These results provide a template for future studies in DN T as well as CD4+ and CD8+ cells in normal and diseased kidneys.


Subject(s)
Acute Kidney Injury , CD8-Positive T-Lymphocytes , Humans , Animals , Mice , CD8-Positive T-Lymphocytes/metabolism , Transcriptome , CD8 Antigens/metabolism , CD4 Antigens/metabolism , Kidney/metabolism , Acute Kidney Injury/pathology , Receptors, Antigen, T-Cell, alpha-beta/metabolism
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