Selection of T cell receptor V beta elements by HLA-DR determinants predisposing to rheumatoid arthritis.

OBJECTIVE. Rheumatoid arthritis (RA) is genetically linked to a sequence motif encoding for the middle portion of the alpha-helical loop, which is adjacent to the antigen-binding groove of the HLA-DR molecule. The disease-associated element might be involved in binding the antigen or in interacting with the T cell receptor (TCR). To investigate the contribution of the disease-associated element in T cell recognition events, we studied structural requirements in the interaction of T cell clones with HLA-DR determinants. METHODS. T cell clones restricted to disease-associated HLA-DR determinants were established by allogeneic stimulation of HLA-DRB1*0401+ or *0401- responders with HLA-DRB1*0404/8+ stimulators. Allele specific primer sets were used to identify the V beta gene segment expressed by individual clones. Sequence analysis was applied to study the diversity of the TCR beta-chain junctional regions. RESULTS. The repertoire of TCR V beta elements was strongly biased toward the usage of V beta 6. HLA-DRB1*0401+ and *0401- donors preferentially recruited V beta 6+ T cells to recognize the disease-associated HLA-DR determinant. Sequence data revealed that the V beta 6.6/7 and V beta 6.8/9 subtypes of the V beta 6 multigene family were overrepresented. The TCR beta chains were characterized by a high degree of junctional diversity, supporting the view that a multitude of peptide-DR complexes were recognized and that the preferential use of V beta 6 was dictated by the TCR beta chain-DR beta 1 chain contact. CONCLUSION. T cells reactive with the disease-associated HLA-DR structure are nonrandomly selected. The HLA-DR component predisposing to RA might define molecular requirements that restrict the TCR-HLA interaction. Thus, the phenomenon of HLA association in RA might reflect a genetic control of T cell recognition, through the selection of the TCR repertoire.     

T cell vaccination induces T cell receptor Vβ-specific Qa-1-restricted regulatory CD8+ T cells

Vaccination of mice with activated autoantigen-reactive CD4⁺ T cells (T cell vaccination, TCV) has been shown to induce protection from the subsequent induction of a variety of experimental autoimmune diseases, including experimental allergic encephalomyelitis (EAE). Although the mechanisms involved in TCV-mediated protection are not completely known, there is some evidence that TCV induces CD8⁺ regulatory T cells that are specific for pathogenic CD4⁺ T cells. Previously, we demonstrated that, after superantigen administration in vivo, CD8⁺ T cells emerge that preferentially lyse and regulate activated autologous CD4⁺ T cells in a T cell receptor (TCR) Vβ-specific manner. This TCR Vβ-specific regulation is not observed in β₂-microglobulin-deficient mice and is inhibited, in vitro, by antibody to Qa-1. We now show that similar Vβ8-specific Qa-1-restricted CD8⁺ T cells are also induced by TCV with activated CD4⁺ Vβ8⁺ T cells. These CD8⁺ T cells specifically lyse murine or human transfectants coexpressing Qa-1 and murine TCR Vβ8. Further, CD8⁺ T cell hybridoma clones generated from B10.PL mice vaccinated with a myelin basic protein-specific CD4⁺Vβ8⁺ T cell clone specifically recognize other CD4⁺ T cells and T cell tumors that express Vβ8 and the syngeneic Qa-1^a but not the allogeneic Qa-1^b molecule. Thus, Vβ-specific Qa-1-restricted CD8⁺ T cells are induced by activated CD4⁺ T cells. We suggest that these CD8⁺ T cells may function to specifically regulate activated CD4⁺ T cells during immune responses.     

Restricted junctional usage of T cell receptor Vβ2 and Vβ13 genes,which are overrepresented on infiltrating T cells in the lips of patients with sjögren's syndrome

Objective. To analyze the clonality of T cell receptor (TCR) Vβ2—and Vβ13—positive T cells, which are predominantly expressed in the lips of patients with Sjögren's syndrome (SS). Methods. The junctional sequences of complementary DNA clones encoding TCR Vβ2 and Vβ13 genes were determined by the polymerase chain reaction. Forty-one Vβ2 and 45 Vβ13 clones established from the lips of 3 SS patients were sequenced. Results. The Vβ2/Jβ2.3 pair was enriched in 2 of the 3 patients (44% and 46% of the clones, respectively), and the Vβ13/Jβ2.1 sequence was dominant in 2 of the 3 (23% and 45%). These pairs were not used preferentially in peripheral blood lymphocytes from the same patients. Conclusion. Infiltrating Vβ2- and Vβ13-positive T cells from the lips of all 3 patients with SS were polyclonal, but the junctional usage of cells from 2 lip samples was restricted, compared with cells from peripheral blood. This suggests that not all expanded cells from the lips of SS patients are stimulated by superantigens.     

Recognition of the antigen-presenting molecule MR1 by a Vδ3+ γδ T cell receptor

Unlike conventional αβ T cells, γδ T cells typically recognize nonpeptide ligands independently of major histocompatibility complex (MHC) restriction. Accordingly, the γδ T cell receptor (TCR) can potentially recognize a wide array of ligands; however, few ligands have been described to date. While there is a growing appreciation of the molecular bases underpinning variable (V)δ1⁺ and Vδ2⁺ γδ TCR-mediated ligand recognition, the mode of Vδ3⁺ TCR ligand engagement is unknown. MHC class I–related protein, MR1, presents vitamin B metabolites to αβ T cells known as mucosal-associated invariant T cells, diverse MR1-restricted T cells, and a subset of human γδ T cells. Here, we identify Vδ1/2⁻ γδ T cells in the blood and duodenal biopsy specimens of children that showed metabolite-independent binding of MR1 tetramers. Characterization of one Vδ3Vγ8 TCR clone showed MR1 reactivity was independent of the presented antigen. Determination of two Vδ3Vγ8 TCR-MR1-antigen complex structures revealed a recognition mechanism by the Vδ3 TCR chain that mediated specific contacts to the side of the MR1 antigen-binding groove, representing a previously uncharacterized MR1 docking topology. The binding of the Vδ3⁺ TCR to MR1 did not involve contacts with the presented antigen, providing a basis for understanding its inherent MR1 autoreactivity. We provide molecular insight into antigen-independent recognition of MR1 by a Vδ3⁺ γδ TCR that strengthens an emerging paradigm of antibody-like ligand engagement by γδ TCRs.

Characterized by both innate and adaptive immune cell functions, γδ T cells are an unconventional T cell subset. While the functional role of γδ T cells is yet to be fully established, they can play a central role in antimicrobial immunity (1), antitumor immunity (2), tissue homeostasis, and mucosal immunity (3). Owing to a lack of clarity on activating ligands and phenotypic markers, γδ T cells are often delineated into subsets based on the expression of T cell receptor (TCR) variable (V) δ gene usage, grouped as Vδ2⁺ or Vδ2⁻.The most abundant peripheral blood γδ T cell subset is an innate-like Vδ2⁺subset that comprises ∼1 to 10% of circulating T cells (4). These cells generally express a Vγ9 chain with a focused repertoire in fetal peripheral blood (5) that diversifies through neonatal and adult life following microbial challenge (6, 7). Indeed, these Vγ9/Vδ2⁺ T cells play a central role in antimicrobial immune response to Mycobacterium tuberculosis (8) and Plasmodium falciparum (9). Vγ9/Vδ2⁺ T cells are reactive to prenyl pyrophosphates that include isopentenyl pyrophosphate and (E)-4-Hydroxy-3-methyl-but-2-enyl pyrophosphate (8) in a butyrophilin 3A1- and BTN2A1-dependent manner (10–13). Alongside the innate-like protection of Vγ9/Vδ2⁺ cells, a Vγ9⁻ population provides adaptive-like immunobiology with clonal expansions that exhibit effector function (14).The Vδ2⁻ population encompasses the remaining γδ T cells but most notably the Vδ1⁺ and Vδ3⁺ populations. Vδ1⁺ γδ T cells are an abundant neonatal lineage that persists as the predominating subset in adult peripheral tissue including the gut and skin (15–18). Vδ1⁺ γδ T cells display potent cytokine production and respond to virally infected and cancerous cells (19). Vδ1⁺ T cells were recently shown to compose a private repertoire that diversifies, from being unfocused to a selected clonal TCR pool upon antigen exposure (20–23). Here, the identification of both Vδ1⁺ T_naive and Vδ1⁺ T_effector subsets and the Vδ1⁺ T_naive to T_effector differentiation following in vivo infection point toward an adaptive phenotype (22).The role of Vδ3⁺ γδ T cells has remained unclear, with a poor understanding of their lineage and functional role. Early insights into Vδ3⁺ γδ T cell immunobiology found infiltration of Vδ3⁺ intraepithelial lymphocytes (IEL) within the gut mucosa of celiac patients (24). More recently it was shown that although Vδ3⁺ γδ T cells represent a prominent γδ T cell component of the gut epithelia and lamina propria in control donors, notwithstanding pediatric epithelium, the expanding population of T cells in celiac disease were Vδ1⁺ (25). Although Vδ3⁺ IELs compose a notable population of gut epithelia and lamina propria T cells (∼3 to 7%), they also formed a discrete population (∼0.2%) of CD4⁻CD8⁻ T cells in peripheral blood (26). These Vδ3⁺ DN γδ T cells are postulated to be innate-like due to the expression of NKG2D, CD56, and CD161 (26). When expanded in vitro, these cells degranulated and killed cells expressing CD1d and displayed a T helper (Th) 1, Th2, and Th17 response in addition to promoting dendritic cell maturation (26). Peripheral Vδ3⁺ γδ T cells frequencies are known to increase in systemic lupus erythematosus patients (27, 28), and upon cytomegalovirus (29) and HIV infection (30), although, our knowledge of their exact role and ligands they recognize remains incomplete.The governing paradigms of antigen reactivity, activation principles, and functional roles of γδ T cells remain unresolved. This is owing partly due to a lack of knowledge of bona fide γδ T cell ligands. Presently, Vδ1⁺ γδ T cells remain the best characterized subset with antigens including Major Histocompatibility Complex (MHC)-I (31), monomorphic MHC-I–like molecules such as CD1b (32), CD1c (33), CD1d (34), and MR1 (35), as well as more diverse antigens such as endothelial protein coupled receptor (EPCR) and phycoerythrin (PE) (36, 37). The molecular determinants of this reactivity were first established for Vδ1⁺ TCRs in complex with CD1d presenting sulfatide (38) and α-galactosylceramide (α-GalCer) (34), which showed an antigen-dependent central focus on the presented lipids and docked over the antigen-binding cleft.In humans, mucosal-associated invariant T (MAIT) cells are an abundant innate-like αβ T cell subset typically characterized by a restricted TCR repertoire (39–43) and reactivity to the monomorphic molecule MR1 presenting vitamin B precursors and drug-like molecules of bacterial origin (41, 44–46). Recently, populations of atypical MR1-restricted T cells have been identified in mice and humans that utilize a more diverse TCR repertoire for MR1-recognition (42, 47, 48). Furthermore, MR1-restricted γδ T cells were identified in blood and tissues including Vδ1⁺, Vδ3⁺, and Vδ5⁺ clones (35). As seen with TRAV 1-2⁻, unconventional MAITs cells the isolated γδ T cells exhibited MR1-autoreactivity with some capacity for antigen discrimination within the responding compartment (35, 48). Structural insight into one such MR1-reactive Vδ1⁺ γδ TCR showed a down-under TCR engagement of MR1 in a manner that is thought to represent a subpopulation of MR1-reactive Vδ1⁺ T cells (35). However, biochemical evidence suggested other MR1-reactive γδ T cell clones would likely employ further unusual docking topologies for MR1 recognition (35).Here, we expanded our understanding of a discrete population of human Vδ3⁺ γδ T cells that display reactivity to MR1. We provide a molecular basis for this Vδ3⁺ γδ T cell reactivity and reveal a side-on docking for MR1 that is distinct from the previously determined Vδ1⁺ γδ TCR-MR1-Ag complex. A Vδ3⁺ γδ TCR does not form contacts with the bound MR1 antigen, and we highlight the importance of non–germ-line Vδ3 residues in driving this MR1 restriction. Accordingly, we have provided key insights into the ability of human γδ TCRs to recognize MR1 in an antigen-independent manner by contrasting mechanisms.     

Anti‐tumour immunotherapy with Vγ9Vδ2 T lymphocytes: from the bench to the bedside

Gamma delta (γδ) Τ cells are non‐conventional T lymphocyte effectors that can interact with and eradicate tumour cells. Several data demonstrate that these T cells, which are implicated in the first line of defence against pathogens, have anti‐tumour activity against many cancers and suggest that γδ Τ cell‐mediated immunotherapy is feasible and might induce objective tumour responses. Due to the importance of γδ Τ lymphocytes in the induction and control of immunity, a complete understanding of their biology is crucial for the development of a potent cancer immunotherapy. This review discusses recent advances in γδ Τ basic research and data from clinical trials on the use of γδ Τ cells in the treatment of different cancers. It analyses how this knowledge might be applied to develop new strategies for the clinical manipulation and the potentiation of γδ Τ lymphocyte activity in cancer immunotherapy.     

Regulation of pulmonary inflammation and fibrosis through expression of integrins αVβ3 and αVβ5 on pulmonary T lymphocytes

Objective

Pulmonary diseases associated with fibrosis, including scleroderma lung disease, are characterized by the accumulation of T cells in the lungs. These cells are thought to facilitate lung fibrosis, but the exact mechanisms of their profibrotic action are not clear. Several αV‐containing integrins, including αVβ3 and αVβ5, have been shown to directly activate transforming growth factor β (TGFβ) and promote collagen accumulation. The aim of this study was to investigate whether pulmonary T cells express profibrotic integrins and regulate collagen accumulation.

Methods

Expression of integrins was assessed by immunohistochemical analysis of lung tissue, by flow cytometry using bronchoalveolar lavage fluid from patients with systemic sclerosis (SSc), and in a CCL18 overexpression animal model of pulmonary T cell infiltration. Experiments in cell cultures were performed to determine whether integrin‐expressing T cells are profibrotic in cocultures with pulmonary fibroblasts and, if so, through what possible mechanism.

Results

Lymphocytes and integrin‐positive cells were present in the lungs, and pulmonary T cells expressed integrins αVβ3 and αVβ5 in patients with SSc and in the animal model. Systemic administration of neutralizing anti–integrin αV antibody or a genetic deficiency of integrin β3 in the CCL18 overexpression model significantly attenuated CCL18‐driven pulmonary lymphocytic infiltration and collagen accumulation. Jurkat T cells overexpressing integrin αVβ3 or integrin αVβ5 in cocultures with primary pulmonary fibroblasts stimulated collagen accumulation and Smad2 nuclear translocation. Neutralizing anti‐TGFβ antibody attenuated the profibrotic effect of integrin‐expressing T cells.

Conclusion

Pulmonary infiltrating T lymphocytes may express integrins αVβ3 and αVβ5 that are necessary for lymphocytic infiltration and T cell–associated TGFβ activation and collagen accumulation.

     

Expanded T cell receptor Vβ–restricted T cells from patients with sporadic inclusion body myositis are proinflammatory and cytotoxic CD28null T cells

Objective

Sporadic inclusion body myositis (IBM) is characterized by T cell infiltrates in muscle tissue, but their functional role is unclear. Systemic signs of inflammation are lacking, and the absence of beneficial effects following immunosuppression has challenged the notion of a role for the immune system. This study was undertaken to investigate the phenotype and functionality of T cells, specifically a subset of proinflammatory, cytotoxic, and apoptosis‐resistant T cells defined as CD28^null T cells, in the pathogenesis of sporadic IBM.

Methods

A cohort of 27 patients with sporadic IBM was analyzed for the frequency of circulating and muscle‐infiltrating CD28^null T cells. The T cell receptor (TCR) V_β usage was determined using flow cytometry and immunohistochemistry. Anti‐CD3–stimulated peripheral blood mononuclear cells were analyzed for intracellular interferon‐γ and cytotoxic potential by flow cytometry.

Results

We found striking accumulations of both CD8+CD28^null and CD4+CD28^null T cells, which represented the TCR V_β–expanded T cells in sporadic IBM. Such CD28^null T cells were abundant both in the inflamed muscle tissue and in the circulation. Although the specific TCR V_β expansions varied between patients, both CD8+CD28^null and CD4+CD28^null T cells consistently displayed a highly proinflammatory and cytotoxic potential.

Conclusion

Our results suggest that CD28null T cell expansions represent the previously described expanded T cell subsets in sporadic IBM, and their proinflammatory capacity and presence in both muscle tissue and the circulation may imply a role of immune activation in sporadic IBM. In addition, CD4+CD28^null T cells may exert cytotoxic effects directly on muscle fibers due to a cytotoxic potential similar to that in CD8+ T cells.

     

Vβ‐restricted T cell adherence to endothelial cells: A mechanism for superantigen‐dependent vascular injury

Objective

To investigate the potential for endothelial cells to operate as superantigen‐presenting cells for T cells and the potential for such an interaction to cause endothelial cell activation and injury.

Methods

Class II major histocompatibility complex (MHC)–positive human umbilical vein endothelial cells (HUVECs) were cocultured for 4 hours with purified T cells and the superantigens staphylococcal enterotoxin B (SEB) or toxic shock syndrome toxin 1 (TSST‐1). After staining with fluorescence‐conjugated monoclonal antibodies, flow cytometric analysis was performed on the HUVECs and T cells to examine V_β‐restricted T cell adherence to the endothelial cell monolayer, V_β‐restricted T cell activation (CD69 up‐regulation), surface expression of endothelial cell activation markers, and generation of endothelial microparticles (EMPs).

Results

Coculture of purified T cells with class II MHC–positive HUVECs and either TSST‐1 or SEB resulted in V_β‐restricted CD69 up‐regulation by CD4 and CD8 cells (V_β2 activation for TSST‐1; V_β3, V_β5.1, and V_β12 activation for SEB). Additionally, there was CD4 and CD8 T cell V_β‐restricted adherence to the HUVEC monolayer at 4 hours. Expression of intercellular adhesion molecule 1, E‐selectin, and vascular cell adhesion molecule 1 was up‐regulated on the class II MHC–positive HUVECs following exposure to superantigen in the presence of T cells, and there was increased EMP release from activated HUVECs, which occurred earlier and was of greater magnitude than that observed in response to tumor necrosis factor α.

Conclusion

Class II MHC–positive endothelial cells operate as competent superantigen‐presenting cells for CD4 and CD8 lymphocytes in vitro. Dual signaling between endothelial cells and T cells results in V_β‐restricted activation and adherence to endothelial monolayers and endothelial cell activation and release of EMPs expressing inducible cell adhesion molecules. It is proposed that this mechanism could account in part for the vascular injury associated with superantigen‐mediated diseases including Kawasaki disease.

     

T cell receptors recognizing type II collagen in HLA–DR–transgenic mice characterized by highly restricted Vβ usage

Objective

To determine the T cell receptor (TCR) structure recognizing type II collagen (CII) in HLA–DR–transgenic mice, and to examine the role of T cells with certain V_β‐chains in collagen‐induced arthritis (CIA).

Methods

T cell hybridomas were established from DR1‐ and DR4‐transgenic mice and selected for their responses to CII and CII peptide containing the T cell determinants. RNA was extracted and reverse transcribed into complementary DNA, which was then amplified using appropriate V_β‐ and V_α‐subfamily–specific primers. The polymerase chain reaction products were purified and directly sequenced. To determine the role of T cells with certain V_β‐chains in CIA, V_β‐subfamily–specific antibodies were administered and the development and characteristics of arthritis were determined.

Results

TCRs of 23 clonally distinct T cell hybridomas that were derived from DR1‐transgenic mice and that were reactive to the CII peptide containing the immunodominant determinant were analyzed. These hybridomas predominantly used the TCR V_β14 and V_β8 gene segments (70% and 30%, respectively). The same restriction in V_β usage was also found in CII‐reactive T cell hybridomas from DR4‐transgenic mice. There was also restricted use of V_α genes, although this was less marked than that of V_β. In contrast, the hybridomas expressed a diverse third complementarity‐determining region. Deletion of both V_β14‐bearing and V_β8‐bearing T cells significantly reduced the incidence and severity of CIA.

Conclusion

These data demonstrate that DR1 and DR4 not only bind and present the same CII immunodominant peptide, but also stimulate a highly restricted subset of T cells.

     

T cell receptor vβ repertoire of double-negative α/β t cells in patients with systemic sclerosis

Objective. To analyze the T cell receptor V_β gene on double-negative (DN) α/β T cells, which are increased in number, on peripheral blood lymphocytes (PBL) from patients with systemic sclerosis (SSc). Methods. The DN α/β T cells were sorted by flow cytometry from PBL obtained from 3 patients with SSc. The V_β repertoire was analyzed by polymerase chain reaction. Results. Only 1 or 2 V_β genes (V_β5/7, 5, or 17) were predominantly expressed on DN α/β T cells from these 3 patients. Conclusion. The V_β repertoire on DN α/β T cells in PBL from patients with SSc is rather restricted.     

T cell receptor Vβ chain restriction and preferred CDR3 motifs of liver‐kidney microsomal antigen (LKM‐1)‐reactive T cells from autoimmune hepatitis patients

Abstract: Aims/Background: The liver‐kidney‐microsomal antigen (LKM‐1) has been recognized as a major CD4⁺ T cell antigen in autoimmune hepatitis (AIH). The aim of this study was to characterize the antigen recognition sites of the variable T cell receptor β‐chain (TCRBV) of T cells specific to LKM‐1. Methods: By repeated stimulation of T cells with a recombinant LKM‐1 antigen or an LKM‐derived peptide followed by limited dilution, we generated T cell clones. Usage of TCRBV was analyzed by RT‐PCR and CDR3 antigen recognition sites were sequenced. Results: The 18 LKM‐1 specific T cell clones isolated from six AIH patients preferentially expressed the TCR elements BV9, BV5S2+S3, BV6, and BV13S1. Four BV9+ T cell clones rearranged the joining element JB1S3 within their CDR3 regions. JB2S3 was detected in another four clones together with BV5S2+S3 or BV13S1. A conserved sequence motif, Q(N)G(X)N, was seen in the diversity regions of five clones (36%). In order to identify T cells expressing the preferred TCRBV molecules in situ, immunohistologic examination of liver biopsies was performed. In AIH patients an accumulation of T cells expressing TCRBV 13S1, BV8 and BV5S3 was observed. Conclusions: Our data define TCRBV restriction and preferred CDR3 features of LKM‐1 specific T cells. The in situ localization of T cells expressing these restricted TCR molecules may suggest a pathogenic relevance of LKM‐1 specific cellular immune responses.     

In Acute Dengue Infection,High TIM-3 Expression May Contribute to the Impairment of IFNγ Production by Circulating Vδ2 T Cells

γδ T cells are innate cells able to quickly eliminate pathogens or infected/tumoral cells by their antiviral and adjuvancy activities. The role of γδ T cells during Dengue Viral Infection (DENV) infection is not fully elucidated. Nevertheless, human primary γδ T cells have been shown to kill in vitro DENV-infected cells, thus highlighting their possible antiviral function. The aim of this work was to characterize the phenotype and function of Vδ2 T cells in DENV patients. Fifteen DENV patients were enrolled for this study and peripheral blood mononuclear cells (PBMC) were used to analyze Vδ2-T-cell frequency, differentiation profile, activation/exhaustion status, and functionality by multiparametric flow cytometry. Our data demonstrated that DENV infection was able to significantly reduce Vδ2-T-cell frequency and to increase their activation (CD38 and HLA-DR) and exhaustion markers (PD-1 and TIM-3). Furthermore, Vδ2 T cells showed a reduced capability to produce IFN-γ after phosphoantigenic stimulation that can be associated to TIM-3 expression. Several studies are needed to depict the possible clinical impact of γδ-T-cell impairment on disease severity and to define the antiviral and immunoregulatory activities of γδ T cells in the first phases of infection.     

Multivalent structure of an αβT cell receptor

Whether there is one or multiple αβT cell antigen receptor (TCR) recognition modules in a given TCR/CD3 complex is a long-standing controversy in immunology. We show that T cells from transgenic mice that coexpress comparable amounts of two distinct TCRβ chains incorporate at least two αβTCRs in a single TCR/CD3 complex. Evidence for bispecific αβTCRs was obtained by immunoprecipitation and immunoblotting and confirmed on the surface of living cells both by fluorescence resonance energy transfer and comodulation assays by using antibodies specific for TCRβ-variable regions. Such (αβ)₂TCR/CD3 or higher-order complexes were evident in T cells studied either ex vivo or after expansion in vitro. T cell activation is thought by many, but not all, to require TCR cross-linking by its antigen/major histocompatibility complex ligand. The implications of a multivalent (αβ)₂TCR/CD3 complex stoichiometry for the ordered docking of specific antigen/major histocompatibility complex, CD4, or CD8 coreceptors and additional TCRs are discussed.     

Divergent T cell receptor γ repertoires in rheumatoid arthritis monozygotic twins

Objective. To determine if the expressed T cell receptor (TCR) γ repertoire is altered in rheumatoid arthritis (RA). Methods. Peripheral blood lymphocytes were collected from monozygotic twins who were either concordant or discordant for RA, or from a normal twin pair. TCR γ-specific complementary DNA libraries were constructed using the anchored polymerase chain reaction. Gene usage was analyzed by plaque hybridization and sequencing. Results. The expressed TCR VΓ repertoires both in RA patients and normal subjects were extremely diverse. Monozygotic twins who were concordant for RA expressed very different frequencies of TCR VΓ genes. Conclusion. RA does not lead to a specific clonal expansion or deletion of TCR VΓ genes in peripheral blood.