Mathematical models of TCR initial triggering.

T cell receptors (TCRs) play crucial roles in regulating T cell response by rapidly and accurately recognizing foreign and non-self antigens. The process involves multiple molecules and regulatory mechanisms, forming a complex network to achieve effective antigen recognition. Mathematical modeling techniques can help unravel the intricate network of TCR signaling and identify key regulators that govern it. In this review, we introduce and briefly discuss relevant mathematical models of TCR initial triggering, with a focus on kinetic proofreading (KPR) models with different modified structures. We compare the topology structures, biological hypotheses, parameter choices, and simulation performance of each model, and summarize the advantages and limitations of them. Further studies on TCR modeling design, aiming for an optimized balance of specificity and sensitivity, are expected to contribute to the development of new therapeutic strategies.

Liposome-based in situ antigen-modification strategy for "universal" T-cell-receptor engineered T cell in cancer immunotherapy.

T-cell receptor (TCR) engineered T-cell therapy, unlike chimeric antigen receptor T-cell therapy, relies on the inherent ability of TCRs to detect a wider variety of antigenic epitopes, such as protein fragments found internally or externally on cells. Hence, TCR-T-cell therapy offers broader possibilities for treating solid tumors. However, because of the complicated process of identifying specific antigenic peptides, their clinical application still encounters significant challenges. Thus, we aimed to establish a novel "universal" TCR-T "artificial antigen expression" technique that involves the delivery of the antigen to tumor cells using DSPE-PEG-NY-ESO-1157-165 liposomes (NY-ESO-1 Lips) to express TCR-T-cell-specific recognition targets. In vitro as well as in vivo studies revealed that they could accumulate efficiently in the tumor area and deliver target antigens to activate the tumor-specific cytotoxic T-cell immune response. NY-ESO-1 TCR-T therapy, when used in combination, dramatically curbed tumor progression and extended the longevity of mice. Additionally, PD-1 blockage enhanced the therapeutic effect of the aforementioned therapy. In conclusion, NY-ESO-1 Lips "cursed" tumor cells by enabling antigenic target expression on their surface. This innovative technique presents a groundbreaking approach for the widespread utilization of TCR-T in solid tumor treatment.

Local Power: The Role of Tissue-Resident Immunity in Human Genital Herpes Simplex Virus Reactivation.

From established latency, human herpes virus type 2 (HSV-2) frequently reactivates into the genital tract, resulting in symptomatic ulcers or subclinical shedding. Tissue-resident memory (TRM) CD8+ T cells that accumulate and persist in the genital skin at the local site of recrudescence are the "first responders" to viral reactivation, performing immunosurveillance and containment and aborting the ability of the virus to induce clinical lesions. This review describes the unique spatiotemporal characteristics, transcriptional signatures, and noncatalytic effector functions of TRM CD8+ T cells in the tissue context of human HSV-2 infection. We highlight recent insights into the intricate overlaps between intrinsic resistance, innate defense, and adaptive immunity in the tissue microenvironment and discuss how rapid virus-host dynamics at the skin and mucosal level influence clinical outcomes of genital herpes diseases.

Unraveling the Role of Reactive Oxygen Species in T Lymphocyte Signaling.

Reactive oxygen species (ROS) are central to inter- and intracellular signaling. Their localized and transient effects are due to their short half-life, especially when generated in controlled amounts. Upon T cell receptor (TCR) activation, regulated ROS signaling is primarily initiated by complexes I and III of the electron transport chain (ETC). Subsequent ROS production triggers the activation of nicotinamide adenine dinucleotide phosphate oxidase 2 (NADPH oxidase 2), prolonging the oxidative signal. This signal then engages kinase signaling cascades such as the mitogen-activated protein kinase (MAPK) pathway and increases the activity of REDOX-sensitive transcription factors such as nuclear factor-kappa B (NF-κB) and activator protein-1 (AP-1). To limit ROS overproduction and prevent oxidative stress, nuclear factor erythroid 2-related factor 2 (Nrf2) and antioxidant proteins such as superoxide dismutases (SODs) finely regulate signal intensity and are capable of terminating the oxidative signal when needed. Thus, oxidative signals, such as T cell activation, are well-controlled and critical for cellular communication.

A bispecific antibody targeting HLA-DQ2.5-gluten peptides potently blocks gluten-specific T cells induced by gluten ingestion in patients with celiac disease.

The gluten-free diet for celiac disease (CeD) is restrictive and often fails to induce complete symptom and/or mucosal disease remission. Central to CeD pathogenesis is the gluten-specific CD4+ T cell that is restricted by HLA-DQ2.5 in over 85% of CeD patients, making HLA-DQ2.5 an attractive target for suppressing gluten-dependent immunity. Recently, a novel anti-HLA-DQ2.5 antibody that specifically recognizes the complexes of HLA-DQ2.5 and multiple gluten epitopes was developed (DONQ52). OBJECTIVE: To assess the ability of DONQ52 to inhibit CeD patient-derived T-cell responses to the most immunogenic gluten peptides that encompass immunodominant T cell epitopes. METHODS: We employed an in vivo gluten challenge model in patients with CeD that affords a quantitative readout of disease-relevant gluten-specific T-cell responses. HLA-DQ2.5+ CeD patients consumed food containing wheat, barley, or rye for 3 days with collection of blood before (D1) and 6 days after (D6) commencing the challenge. Peripheral blood mononuclear cells were isolated and assessed in an interferon (IFN)-γ enzyme-linked immunosorbent spot assay (ELISpot) testing responses to gluten peptides encompassing a series of immunodominant T cell epitopes. The inhibitory effect of DONQ52 (4 or 40 µg/mL) was assessed and compared to pan-HLA-DQ blockade (SPVL3 antibody). RESULTS: In HLA-DQ2.5+ CeD patients, DONQ52 reduced T cell responses to all wheat gluten peptides to an equivalent or more effective degree than pan-HLA-DQ antibody blockade. It reduced T cell responses to a cocktail of the most immunodominant wheat epitopes by a median of 87% (IQR 72-92). Notably, DONQ52 also substantially reduced T-cell responses to dominant barley hordein and rye secalin derived peptides. DONQ52 had no effect on T-cell responses to non-gluten antigens. CONCLUSION: DONQ52 can significantly block HLA-DQ2.5-restricted T cell responses to the most highly immunogenic gluten peptides in CeD. Our findings support in vitro data that DONQ52 displays selectivity and broad cross-reactivity against multiple gluten peptide:HLA-DQ2.5 complexes. This work provides proof-of-concept multi-specific antibody blockade has the potential to meaningfully inhibit pathogenic gluten-specific T-cell responses in CeD and supports ongoing therapeutic development.

MAIT cell-MR1 reactivity is highly conserved across multiple divergent species.

Mucosal-associated invariant T (MAIT) cells are a subset of unconventional T cells that recognize small molecule metabolites presented by major histocompatibility complex class I related protein 1 (MR1), via an αß T cell receptor (TCR). MAIT TCRs feature an essentially invariant TCR α-chain, which is highly conserved between mammals. Similarly, MR1 is the most highly conserved major histocompatibility complex-I-like molecule. This extreme conservation, including the mode of interaction between the MAIT TCR and MR1, has been shown to allow for species-mismatched reactivities unique in T cell biology, thereby allowing the use of selected species-mismatched MR1-antigen (MR1-Ag) tetramers in comparative immunology studies. However, the pattern of cross-reactivity of species-mismatched MR1-Ag tetramers in identifying MAIT cells in diverse species has not been formally assessed. We developed novel cattle and pig MR1-Ag tetramers and utilized these alongside previously developed human, mouse, and pig-tailed macaque MR1-Ag tetramers to characterize cross-species tetramer reactivities. MR1-Ag tetramers from each species identified T cell populations in distantly related species with specificity that was comparable to species-matched MR1-Ag tetramers. However, there were subtle differences in staining characteristics with practical implications for the accurate identification of MAIT cells. Pig MR1 is sufficiently conserved across species that pig MR1-Ag tetramers identified MAIT cells from the other species. However, MAIT cells in pigs were at the limits of phenotypic detection. In the absence of sheep MR1-Ag tetramers, a MAIT cell population in sheep blood was identified phenotypically, utilizing species-mismatched MR1-Ag tetramers. Collectively, our results validate the use and define the limitations of species-mismatched MR1-Ag tetramers in comparative immunology studies.

Detecting T-cell clonal expansions and quantifying clone survival using deep profiling of immune repertoires.

An individual's T-cell repertoire constantly changes under the influence of external and internal factors. Cells that do not receive a stimulatory signal die, while those that encounter and recognize a pathogen or receive a co-stimulatory signal divide, resulting in clonal expansions. T-cell clones can be traced by monitoring the presence of their unique T-cell receptor (TCR) sequence, which is assembled de novo through a process known as V(D)J rearrangement. Tracking T cells can provide valuable insights into the survival of cells after hematopoietic stem cell transplantation (HSCT) or cancer treatment response and can indicate the induction of protective immunity by vaccination. In this study, we report a bioinformatic method for quantifying the T-cell repertoire dynamics from TCR sequencing data. We demonstrate its utility by measuring the T-cell repertoire stability in healthy donors, by quantifying the effect of donor lymphocyte infusion (DLI), and by tracking the fate of the different T-cell subsets in HSCT patients and the expansion of pathogen-specific clones in vaccinated individuals.

Immune checkpoint therapy responders display early clonal expansion of tumor infiltrating lymphocytes.

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.

Efficient and economic protein labeling for NMR in mammalian expression systems: Application to a preT-cell and T-cell receptor protein.

Protein nuclear magnetic resonance (NMR) spectroscopy relies on the ability to isotopically label polypeptides, which is achieved through heterologous expression in various host organisms. Most commonly, Escherichia coli is employed by leveraging isotopically substituted ammonium and glucose to uniformly label proteins with 15N and 13C, respectively. Moreover, E. coli can grow and express proteins in uniformly deuterium-substituted water (D2O), a strategy useful for experiments targeting high molecular weight proteins. Unfortunately, many proteins, particularly those requiring specific posttranslational modifications like disulfide bonding or glycosylation for proper folding and/or function, cannot be readily expressed in their functional forms using E. coli-based expression systems. One such class of proteins includes T-cell receptors and their related preT-cell receptors. In this study, we present an expression system for isotopic labeling of proteins using a nonadherent human embryonic kidney cell line, Expi293F, and a specially designed media. We demonstrate the application of this platform to the ß subunit common to both receptors. In addition, we show that this expression system and media can be used to specifically label amino acids Phe, Ile, Val, and Leu in this system, utilizing an amino acid-specific labeling protocol that allows targeted incorporation at high efficiency without significant isotopic scrambling. We demonstrate that this system can also be used to express proteins with fluorinated amino acids. We were routinely able to obtain an NMR sample with a concentration of 200 µM from 30 mL of culture media, utilizing less than 20 mg of the labeled amino acids.

Atovaquone enhances antitumor efficacy of TCR-T therapy by augmentation of ROS-induced ferroptosis in hepatocellular carcinoma.

T-cell receptor (TCR) engineered T-cell therapy has recently emerged as a promising adoptive immunotherapy approach for tumor treatment, yet hindered by tumor immune evasion resulting in poor therapeutic efficacy. The introduction of ferroptosis-targeted inducers offers a potential solution, as they empower T cells to induce ferroptosis and exert influence over the tumor microenvironment. Atovaquone (ATO) stands as a prospective pharmaceutical candidate with the potential to target ferroptosis, effectively provoking an excessive generation and accumulation of reactive oxygen species (ROS). In this study, we evaluated the effectiveness of a combination therapy comprising ATO and TCR-T cells against hepatocellular carcinoma (HCC), both in vitro and in vivo. The results of lactate dehydrogenase and cytokine assays demonstrated that ATO enhanced cytotoxicity mediated by AFP-specific TCR-T cells and promoted the release of IFN-γ in vitro. Additionally, in an established HCC xenograft mouse model, the combined therapy with low-dose ATO and TCR-T cells exhibited heightened efficacy in suppressing tumor growth, with no apparent adverse effects, comparable to the results achieved through monotherapy. The RNA-seq data unveiled a significant activation of the ferroptosis-related pathway in the combination therapy group in comparison to the TCR-T cells group. Mechanistically, the synergy between ATO and TCR-T cells augmented the release of IFN-γ by TCR-T cells, while concurrently elevating the intracellular and mitochondrial levels of ROS, expanding the labile iron pool, and impairing the integrity of the mitochondrial membrane in HepG2 cells. This multifaceted interaction culminated in the potentiation of ferroptosis within the tumor, primarily induced by an excess of ROS. In summary, the co-administration of ATO and TCR-T cells in HCC exhibited heightened vulnerability to ferroptosis. This heightened susceptibility led to the inhibition of tumor growth and the stimulation of an anti-tumor immune response. These findings suggest that repurposing atovaquone for adoptive cell therapy combination therapy holds the potential to enhance treatment outcomes in HCC.

Dynamic establishment of recipient resident memory T cell repertoire after human intestinal transplantation.

BACKGROUND: Understanding formation of the human tissue resident memory T cell (TRM) repertoire requires longitudinal access to human non-lymphoid tissues. METHODS: By applying flow cytometry and next generation sequencing to serial blood, lymphoid tissue, and gut samples from 16 intestinal transplantation (ITx) patients, we assessed the origin, distribution, and specificity of human TRMs at phenotypic and clonal levels. FINDINGS: Donor age ≥1 year and blood T cell macrochimerism (peak level ≥4%) were associated with delayed establishment of stable recipient TRM repertoires in the transplanted ileum. T cell receptor (TCR) overlap between paired gut and blood repertoires from ITx patients was significantly greater than that in healthy controls, demonstrating increased gut-blood crosstalk after ITx. Crosstalk with the circulating pool remained high for years of follow-up. TCR sequences identifiable in pre-Tx recipient gut but not those in lymphoid tissues alone were more likely to populate post-Tx ileal allografts. Clones detected in both pre-Tx gut and lymphoid tissue had distinct transcriptional profiles from those identifiable in only one tissue. Recipient T cells were distributed widely throughout the gut, including allograft and native colon, which had substantial repertoire overlap. Both alloreactive and microbe-reactive recipient T cells persisted in transplanted ileum, contributing to the TRM repertoire. INTERPRETATION: Our studies reveal human intestinal TRM repertoire establishment from the circulation, preferentially involving lymphoid tissue counterparts of recipient intestinal T cell clones, including TRMs. We have described the temporal and spatial dynamics of this active crosstalk between the circulating pool and the intestinal TRM pool. FUNDING: This study was funded by the National Institute of Allergy and Infectious Diseases (NIAID) P01 grant AI106697.

Characterization of T-Cell receptor repertoire in immunoglobulin a nephropathy.

Immunoglobulin A nephropathy (IgAN) is an autoimmune disease characterized by abnormal IgA deposition in glomerulus. Current diagnosis of IgAN still depends on renal biopsy, an invasive method that might increase the risk of clinical outcomes. Therefore, we aimed to explore the characteristics of T cell repertoire in IgAN from peripheral blood samples for identifying innovative diagnostic biomarkers. Herein, we included 8 IgAN patients, 25 non-IgAN patients, and 10 healthy controls in the study. A high-throughput immune repertoire sequencing was conducted to investigate the T-cell receptor beta-chain (TCRß) repertoire of peripheral blood. Characteristics of TCRß repertoire were assessed for these three distinct groups. A reduced TCRß repertoire diversity was observed in IgAN patients compared to non-IgAN and healthy individuals. A skewed distribution toward shorter TCRß complementarity determining region (CDR3) length was found in non-IgAN relative to IgAN patients. In addition, the differences in usages of five TRBV genes (TRBV5-4, TRBV6-4, TRBV12-1, TRBV16, and TRBV21-1) were identified between IgAN, non-IgAN, and healthy subjects. Of note, the TRBV6-4 gene, which is associated with mucosal-associated invariant T (MAIT) cells, exhibited higher usage in IgAN patients, suggesting potential importance of MAIT cells in IgAN. In short, our findings supported TCR repertoire characteristics as potential biomarkers for IgAN diagnosis.

Large-scale integrative analysis of juvenile idiopathic arthritis for new insight into its pathogenesis.

BACKGROUND: Juvenile idiopathic arthritis (JIA) is one of the most prevalent rheumatic disorders in children and is classified as an autoimmune disease (AID). While a robust genetic contribution to JIA etiology has been established, the exact pathogenesis remains unclear. METHODS: To prioritize biologically interpretable susceptibility genes and proteins for JIA, we conducted transcriptome-wide and proteome-wide association studies (TWAS/PWAS). Then, to understand the genetic architecture of JIA, we systematically analyzed single-nucleotide polymorphism (SNP)-based heritability, a signature of natural selection, and polygenicity. Next, we conducted HLA typing using multi-ethnicity RNA sequencing data. Additionally, we examined the T cell receptor (TCR) repertoire at a single-cell level to explore the potential links between immunity and JIA risk. RESULTS: We have identified 19 TWAS genes and two PWAS proteins associated with JIA risks. Furthermore, we observe that the heritability and cell type enrichment analysis of JIA are enriched in T lymphocytes and HLA regions and that JIA shows higher polygenicity compared to other AIDs. In multi-ancestry HLA typing, B*45:01 is more prevalent in African JIA patients than in European JIA patients, whereas DQA1*01:01, DQA1*03:01, and DRB1*04:01 exhibit a higher frequency in European JIA patients. Using single-cell immune repertoire analysis, we identify clonally expanded T cell subpopulations in JIA patients, including CXCL13+BHLHE40+ TH cells which are significantly associated with JIA risks. CONCLUSION: Our findings shed new light on the pathogenesis of JIA and provide a strong foundation for future mechanistic studies aimed at uncovering the molecular drivers of JIA.

Dynamics of T-cell receptor repertoire in patients with ankylosing spondylitis after biologic therapy.

INTRODUCTION: Ankylosing spondylitis (AS) is a chronic inflammatory autoimmune disease in which T-cell immune responses play important roles. AS has been characterized by altered T-cell receptor (TCR) repertoire profiles, which are thought to be caused by expansion of disease-related TCR clonotypes. However, how biological agents affect the TCR repertoire status and whether their therapeutic outcomes are associated with certain features or dynamic patterns of the TCR repertoire are still elusive. MATERIAL AND METHODS: We collected clinical samples from AS patients pre- and post-treatment with biologics. TCR repertoire sequencing was conducted to investigate associations of TCRα and TCRß repertoire characteristics with disease activity and inflammatory indicators/cytokines. RESULTS: Our results showed that good responders were associated with an increase in the TCR repertoire diversity with higher proportions of contracted TCR clonotypes. Additionally, we further identified a positive correlation between TCR repertoire diversity and interleukin (IL)-23 levels in AS patients. A network analysis revealed that contracted AS-associated TCR clonotypes with the same complementary-determining region 3 (CDR3) motifs, which represented high probabilities of sharing TCR specificities to AS-related antigens, were dominant in good responders of AS after treatment with biologic therapies. CONCLUSIONS: Our findings suggested an important connection between TCR repertoire changes and therapeutic outcomes in biologic-treated AS patients. The status and dynamics of TCR repertoire profiles are useful for assessing the prognosis of biologic treatments in AS patients.

TCRß clones in muscle tissue share structural features in patients with idiopathic inflammatory myopathy and are associated with disease activity.

Objectives: To characterize the T cell receptor (TCRß) repertoire in peripheral blood and muscle tissues of treatment naïve patients with newly diagnosed idiopathic inflammatory myopathies (IIMs). Methods: High throughput RNA sequencing of the TCRß chain was performed in peripheral blood and muscle tissue in twenty newly-diagnosed treatment-naïve IIM patients (9 DM, 5 NM/OM, 5 IMNM and 1 ASyS) and healthy controls. Results thereof were correlated with markers of disease activity. Results: Muscle tissue of IIM patients shows more expansion of TCRß clones and decreased diversity when compared to peripheral blood of IIM as well as healthy controls (both p=0.0001). Several expanded TCRß clones in muscle are tissue restricted and cannot be retrieved in peripheral blood. These clones have significantly longer CDR3 regions when compared to clones (also) found in circulation (p=0.0002), while their CDR3 region is more hydrophobic (p<0.01). Network analysis shows that clonal TCRß signatures are shared between patients. Increased clonal expansion in muscle tissue is significantly correlated with increased CK levels (p=0.03), while it tends to correlate with decreased muscle strength (p=0.08). Conclusion: Network analysis of clones in muscle of IIM patients shows shared clusters of sequences across patients. Muscle-restricted CDR3 TCRß clones show specific structural features in their T cell receptor. Our results indicate that clonal TCRß expansion in muscle tissue might be associated with disease activity. Collectively, these findings support a role for specific clonal T cell responses in muscle tissue in the pathogenesis of the IIM subtypes studied.

Analysis of tumor-related features of non-small cell lung cancer based on TCR repertoire workflow / 上海交通大学学报（医学版）

Objective·To explore the immune-related characteristics of non-small cell lung cancer(NSCLC),discover potential tumor markers in V-J genes,and lay the foundation for establishing a TCR-antigen recognition prediction model.Methods·A total of 704 NSCLC samples were collected to establish a comprehensive T-cell receptor(TCR)repertoire analysis workflow.The upstream analysis included steps such as raw data processing,quality control,filtering,TCR sequence identification,and extraction.The downstream analysis included repertoire clone distribution,clone typing,V-J gene sharing,CDR3 distribution characteristics,and clone tracking.The sample clone distribution was analyzed by using indices such as Shannon-Weiner index and Chaol index.Clone typing was performed based on the number of clone amplifications to explore differences among different types.The degree of V-J gene segment sharing was analyzed,and the sharing of low-frequency clone types was determined through clone amplification weight analysis of V-J genes by using two samples of papillary thyroid carcinoma.Finally,analysis of the distribution characteristics of V genes and high-frequency clone type CDR3,and clone tracking analysis were conducted to monitor changes in tumor immune clone frequencies before and after analysis,aiming to identify potential tumor markers.Results·① Significant differences were observed in clone distribution and clone typing among different NSCLC tissues,as well as among different ages and genders.② Specific highly-shared V-J genes were identified in the analysis of V-J gene sharing,and non-normal distribution of high-clone V genes and amino acid high-frequency clone types were found in the CDR3 distribution analysis.③ In the analysis of high-frequency clone type clone tracking,highly expressed or newly expressed high-frequency clone types were observed in NSCLC,suggesting that these clone types could serve as potential tumor-associated antigens or bind with CDR3 reference sequences of new antigens.④ It was found that the expression frequency of TRBJ2-5 gene,originally low-expressed,significantly increased,indicating its potential role as a key low-frequency gene in tumor immune response.Conclusion·The TRAV21 and TRBV6.5 genes show high clone amplification in NSCLC and could serve as potential tumor biomarkers.

Defectos en la expresión de cadena zeta en un grupo de pacientes con lupus, escleroderma y artritis de inicio tardío, Colombia 2014 / Defects in the Zeta Chain Expression in a Group of Patients with SLE, Scleroderma and Late-onset Arthritis, Colombia 2014 / Defeitos na expressão de cadeia zeta em um grupo de pacientes com Lúpus, Esclerodermia e artrite de início tardio, Colômbia 2014

Introducción: El lupus eritematoso sistémico (LES), la escleroderma y la artritis de inicio tardío son enfermedades inflamatorias autoinmunes (EIA) caracterizadas por la producción de autoanticuerpos y presencia de células T anormales, las cuales generan respuesta inmune defectuosa. La expresión anormal de moléculas clave en señalización y la función defectuosa de los linfocitos T cumplen un papel significativo en la patogénesis de la enfermedad autoinmune. Las células T muestran numerosas anormalidades en la señalización del complejo receptor de célula T cadena zeta (TCRζ) estas aberraciones resultan en la alteración de la expresión de citoquinas y algunos eventos bioquímicos involucrados en la expresión de moléculas de superficie. Los defectos en el complejo TCRζpueden estar asociados al uso de corticoides, utilizados en pacientes con enfermedad autoinmune, debido a su potente actividad antiinflamatoria y propiedades inmunosupresoras. Los corticoides sintéticos como la dexametasona inhiben la actividad trascripcional de algunos factores como NFkB y AP-1 los cuales regulan la síntesis de algunas citoquinas y podrían estar involucrados en la síntesis de TCRζ. Objetivos: Evaluar la asociación de los defectos de la expresión de cadena zeta (ζ), en células T de pacientes con enfermedad autoinmune sin tratamiento con corticoides. Los defectos en la expresión defectuosa de zeta, proteína asociada al receptor TCR, altera la activación normal del linfocito T. Materiales y métodos: Estudio analítico de casos y controles, con una relación 1:1 (13:13). Los casos fueron pacientes con enfermedad autoinmune activa (6 pacientes con LES, 5 pacientes con escleroderma y 2 pacientes con artritis de inicio tardío), y que no hubieran iniciado tratamiento con corticoides, los controles fueron pacientes sin diagnóstico de enfermedad autoinmune. El diagnóstico se hizo a través de los criterios establecidos por el Colegio Americano de Reumatología para pacientes con LES, escleroderma y artritis de inicio tardío. Se realizó venopunción extrayendo 10ml de sangre total, se extrajo RNA total y se hizo RT PCR, se amplificó utilizando un juego de primers que flanquean una región de 138 pares de bases que involucraban los exones 2, 3 y 4 de cadena ζ. Resultados: En los valores de amplificación de cadena Z se encontraron diferencias significativas en pacientes con enfermedad autoinmune (0,8214±0,1787, med=0,7368) comparada con el grupo control (0,9225±0,1272, med=0,9830) (p=0,045, Test no-paramétrico, exacto de Mann Whitney a una cola). Conclusión: La expresión de cadena Z se encontró disminuida en células T de pacientes con enfermedad autoinmune, sin uso de corticoides, la disminución o una falta de expresión de la cadena Z puede causar alteraciones en la respuesta inmune.

Introduction: Systemic Lupus Erythematosus (SLE), Scleroderma and late-onset arthritis are autoimmune inflammatory diseases (EIA) characterized by autoantibody production and presence of abnormal T cells which generate defective immune response. The abnormal expression of key signaling molecules in the defective function of T-lymphocytes plays a significant role in the pathogenesis of autoimmune disease. The T-cells exhibit numerous abnormalities TCRζ1 signaling complex, these aberrations result in altered expression of cytokines and some biochemical events involved in the expression of surface molecules. Defects in the complex may be associated TCR ζ to steroids used in autoimmune disease patients due to their powerful anti- inflammatory activity and immunosuppressive properties. The synthetic corticosteroids such as dexamethasone inhibit the transcriptional activity of some factors such as NFKB and AP-1, which regulate the synthesis of certain cytokines and could be involved in the TCRζ synthesis. Material and Methods: A case-control study, with a 1:1 ratio of cases and controls (13:13). Cases were patients with active autoimmune disease (6 patients with SLE, 5 patients with scleroderma and 2 patients with lateonset arthritis), who have not started treatment with corticosteroids. Controls were patients with no autoimmune disease. The diagnosis was made by the criteria established by the American College of Rheumatology for patients with SLE, scleroderma and late-onset arthritis. A 10 mL sample was obtained by venipuncture whole blood. Total RNA was extracted and RT-PCR was performed using a set of primers flanking a region of 138 base pairs involving exons 2, 3 and 4 of the ζchain. Results: The values of Z chain amplification showed significant differences in patients with autoimmune disease (0.8214 ± 0.1787, med = 0.7368) compared with the control group (0.9225 ± 0.1272, med = 0.9830) (p = 0.045, Mann-Withney non-parametric one tailed exact test). Conclusion: We observed a reduced level of in the zeta chain expression in T cells in patients with autoimmune disease without use of corticosteroids.

Introdução: O Lúpus Eritematoso Sistêmico (LES), Esclerodermia e Artite de início tardio são doenças inflamatórias autoimunes caracterizadas por produção de autoanticorpos e presença de células T anormais as quais geram resposta imune defeituosa. A expressão anormal de moléculas chave em sinalização e a função defeituosa dos linfócitos T cumprem um papel significativo na patogênese da doença autoimune. As células T mostram numerosas anormalidades na sinalização do Complexo Receptor de célula T cadeia zeta (TCRζ)1, estas aberrações resultam na alteração da expressão de citocinas e alguns eventos bioquímicos envolvidos na expressão de moléculas de superfície. Os defeitos no complexo TCRζ podem estar associados ao uso de corticoides, utilizados em pacientes com doença autoimune devido a seu potente atividade auto-inflamatória e propriedades imunossupressoras. Os corticoides sintéticos como a dexametasona inibem a atividade transcricional de alguns fatores como NFkB e AP-1 os quais regulam a síntese de algumas citocinas e poderiam estar envolvidas na síntese de TCRζ2, 3. Objetivos: Avaliar a associação dos defeitos da expressão de cadeia zeta (ζ), em células T de pacientes com doença autoimune sem tratamento com corticoides. Os defeitos na expressão defeituosa de zeta, proteína associada ao receptor TCR altera a ativação normal do linfócito T. Materiais e métodos: Estudo analítico de casos e controles, com uma relação 1:1 (13:13). Os casos foram pacientes com doença autoimune ativa (6 pacientes com LES, 5 pacientes com esclerodermia e 2 pacientes com artrite de início tardio), e que não tenham iniciado tratamento com corticoides e os controles foram pacientes sem diagnóstico de doença autoimune. O diagnóstico se fez através dos critérios estabelecidos pelo Colegio Americano de Reumatología para pacientes com LES, esclerodermia e artrite de início tardio. Se realizou venopunção extraindo 10mls de sangue total, se extraiu RNA total e se fez RT PCR, se amplificou utilizando um jogo de primers que flanqueiam uma região de 138 pares de bases que envolviam os exões 2, 3 e 4 de cadeia ζ. Resultados: Nos valores de amplificação de cadeia Z se encontraram diferenças significativas em pacientes com doença autoimune (0.8214±0.1787, med=0.7368) comparada com o grupo controle (0.9225±0.1272, med=0.9830) (p=0.045, Teste não paramétrico, exato de Mann Whitney) Conclusão: A expressão de cadeia Z encontrou-se diminuída em células T de pacientes com doença autoimune, sem uso de corticoides, a diminuição ou uma falta de expressão da cadeia Z pode causar alterações na resposta imune.

Células T y sus receptores αß y γδ en biopsias de pacientes con enfermedad periodontal / T cells and its receptords and αß and γδ in biopsies from patients with periodontal disease

El propósito de este estudio es determinar la presencia y localización de las células T y de sus receptores αβ y γδ en biopsias de tejido gingival de pacientes con enfermedad periodontal. Se evaluaron 60 biopsias de 12 pacientes, 4 con diagnostico de periodontitis agresiva, 4 con periodontitis crónica y 4 con gingivitis, las cuales fueron procesados para su análisis histológico, inmunohistoquímico e histomorfometrico. Al analizar los resultados por diagnostico los marcadores que mas predominaron fueron, en Gingivitis CD3, CD8 y TCR γδ en tejido conectivo. En Periodontitis crónica CD3, CD8 y TCR γδ en epitelio oral y CD4 el cual presentó una expresión homogénea en los tejidos analizados. En periodontitis agresiva CD3 y CD8 en epitelio crevicular, con una distribución similar entre CD4 y CD8 tanto en epitelio oral como en tejido conectivo y TCR γδ en conectivo. En cuanto a las cadenas variables del TCR Vβ los más expresados en las diferentes patologías estudiadas fueron el 6.7, 8.1 y 12 a nivel del tejido conectivo. Los estudios sobre la expresión de estas familias parecen indicar que es otra vía de activación a tener en cuenta dentro del modelo de la patogenia de la enfermedad y que debe ser estudiado en modelos longitudinales en pacientes con pérdida de inserción progresiva.

T the purpose of this study is identifying the presence and localization of T cells and their receptor αβ and γδ in biopsies of gingival tissue in patients with periodontal disease. 60 biopsies were evaluated in 12 patients, 4 patients with diagnosis of gingivitis, 4 patients with chronic periodontitis and 4 with aggressive periodontitis, which were processed for the histological, immunohistochemical and histomorphometric analysis. The results by diagnosis showed that in gingivitis the more predominant markers were CD3, CD8 and TCR γδ in connective tissue. In chronic periodontitis the markers with bigger expression were CD3, CD8 and TCR γδ in oral epithelium and CD4 that showed a homogeneous behavior in the analized tissues. In aggressive periodontitis CD3 and CD8 in surcular epithelium, TCR γδ in connective tissue and CD4 and CD8 with a similar distribution in oral epithelium and connective tissue. In relation with variable chains of TCR Vβ, the most predominat in the different diagnosis were 6.7,8.1 and 12 in connective tissue. The investigations about the expression of these families indicate that it can be other important via of activation in the pathogenesis of periodontal disease and it should be study in longitudinal models in patients with progressive loss of attachment level.

Linfocitos T reguladores: subpoblaciones, mecanismo de acción e importancia en el control de la autoinmunidad / T regulatory lymphocytes: subpopulations, mechanism of action and importance in the control of autoimmunity

La regulación inmunológica constituye tanto un mecanismo importante para el mantenimiento de la homeostasis del sistema inmune como para el establecimiento de la tolerancia hacia antígenos propios evitando el desarrollo de enfermedades autoinmunitarias. Así mismo, juega un papel relevante en el mantenimiento de la tolerancia periférica mediante el control de una pequeña población de células T circulantes denominadas células T reguladoras (Treg), las cuáles parecen haber migrado del timo durante estadios relativamente tardíos¹. El término "células T reguladoras" se refiere a células que activan o suprimen la función de otras células. Aparentemente, controlan el desarrollo de enfermedades autoinmunitarias (lupus, tiroiditis, diabetes tipo I y enfermedad inflamatoria intestinal entre otras) el rechazo de injertos, y pueden jugar un papel crítico en el control del asma y la alergia.

Immune regulation is both an important mechanism for maintaining immune system homeostasis and for the establishment of tolerance towards self antigens in order to prevent the development of autoimmune diseases. It also plays an important role in maintaining peripheral tolerance by controlling a small population of circulating T cells, called regulatory T cells (Treg), which seems to have migrated from the thymus during relatively late stages¹. The term "regulatory T cells" refers to cells that activate or suppress the function of other cells. Apparently, controlling the development of autoimmune diseases (For instance, lupus, thyroiditis, type I diabetes and inflammatory bowel disease among others), graft rejection and may play a critical role in asthma and allergy.