The T-cell-receptor repertoire in the synovial fluid of a patient with rheumatoid arthritis is polyclonal

Shared recognition of citrullinated tenascin-C peptides by T and B cells in rheumatoid arthritis

Tenascin-C (TNC), an extracellular matrix protein that has proinflammatory properties, is a recently described antibody target in rheumatoid arthritis (RA). In this study, we utilized a systematic discovery process and identified 5 potentially novel citrullinated TNC (cit-TNC) T cell epitopes. CD4⁺ T cells specific for these epitopes were elevated in the peripheral blood of subjects with RA and showed signs of activation. Cit-TNC–specific T cells were also present among synovial fluid T cells and secreted IFN-γ. Two of these cit-TNC T cell epitopes were also recognized by antibodies within the serum and synovial fluid of individuals with RA. Detectable serum levels of cit-TNC–reactive antibodies were prevalent among subjects with RA and positively associated with cyclic citrullinated peptide (CCP) reactivity and the HLA shared epitope. Furthermore, cit-TNC–reactive antibodies were correlated with rheumatoid factor and elevated in subjects with a history of smoking. This work confirms cit-TNC as an autoantigen that is targeted by autoreactive CD4⁺ T cells and autoantibodies in patients with RA. Furthermore, our findings raise the possibility that coinciding epitopes recognized by both CD4⁺ T cells and B cells have the potential to amplify autoimmunity and promote the development and progression of RA.

An ELISA Lab-on-a-Chip (ELISA-LOC)

Laminated object manufacturing (LOM) technology using polymer sheets is an easy and affordable method for rapid prototyping of Lab-on-a-Chip (LOC) systems. It has recently been used to fabricate a miniature 96 sample ELISA lab-on-a-chip (ELISA-LOC) by integrating the washing step directly into an ELISA plate. LOM has been shown to be capable of creating complex 3D microfluidics through the assembly of a stack of polymer sheets with features generated by laser micromachining and by bonding the sheets together with adhesive. A six layer ELISA-LOC was fabricated with an acrylic (poly(methyl methacrylate) (PMMA)) core and five polycarbonate layers micromachined by a CO(2) laser with simple microfluidic features including a miniature 96-well sample plate. Immunological assays can be carried out in several configurations (1 × 96 wells, 2 × 48 wells, or 4 × 24 wells). The system includes three main functional elements: (1) a reagent loading fluidics module, (2) an assay and detection wells plate, and (3) a reagent removal fluidics module. The ELISA-LOC system combines several biosensing elements: (1) carbon nanotube (CNT) technology to enhance primary antibody immobilization, (2) sensitive ECL (electrochemiluminescence) detection, and (3) a charge-coupled device (CCD) detector for measuring the light signal generated by ECL. Using a sandwich ELISA assay, the system detected Staphylococcal enterotoxin B (SEB) at concentrations as low as 0.1 ng/ml, a detection level similar to that reported for conventional ELISA. ELISA-LOC can be operated by a syringe and does not require power for operation. This simple point-of-care (POC) system is useful for carrying out various immunological assays and other complex medical assays without the laboratory required for conventional ELISA, and therefore may be more useful for global healthcare delivery.

Molecular requirements for T cell recognition of N-myristoylated peptides derived from the simian immunodeficiency virus Nef protein

We have recently isolated a rhesus macaque cytotoxic T cell line, 2N5.1, that specifically recognizes an N-myristoylated 5-mer peptide (C(14)-Gly-Gly-Ala-Ile-Ser [C14nef5]) derived from the simian immunodeficiency virus (SIV) Nef protein. Such C14nef5-specific T cells expand in the circulation of SIV-infected monkeys, underscoring the capacity of T cells to recognize viral lipopeptides; however, the molecular basis for the lipopeptide antigen presentation remains to be elucidated. Here, functional studies indicated that the putative antigen-presenting molecule for 2N5.1 was likely to have two separate antigen-binding sites, one for interaction with a C(14)-saturated acyl chain and the other for anchorage of the C-terminal serine residue. Mutants with alanine substitutions for the second glycine residue and the fourth isoleucine residue were not recognized by 2N5.1 but interfered with the presentation of C14nef5 to 2N5.1, indicating that these structural analogues retained the ability to interact with the antigen-presenting molecules. In contrast to the highly specific recognition of C14nef5 by 2N5.1, an additional cytotoxic T cell line, SN45, established independently from a C14nef5-stimulated T cell culture, showed superb reactivity to both C14nef5 and an N-myristoylated Nef 4-mer peptide, and therefore, the C-terminal serine residue was dispensable for the recognition of lipopeptides by the SN45 T cells. Furthermore, the mutants with alanine substitutions were indeed recognized by the SN45 T cells. Given that N-myristoylation of the Nef protein occurs in the conserved motifs and is critical for viral pathogenesis, these observations predict that the lipopeptide-specific T cell response is difficult for viruses to avoid by simply introducing amino acid mutations.

An automated point-of-care system for immunodetection of staphylococcal enterotoxin B

An automated point-of-care (POC) immunodetection system for immunological detection of staphylococcal enterotoxin B (SEB) was designed, fabricated, and tested. The system combines several elements: (i) enzyme-linked immunosorbent assay-lab-on-a-chip (ELISA-LOC) with fluidics, (ii) a charge-coupled device (CCD) camera detector, (iii) pumps and valves for fluid delivery to the ELISA-LOC, (iv) a computer interface board, and (v) a computer for controlling the fluidics, logging, and data analysis of the CCD data. The ELISA-LOC integrates a simple microfluidic system into a miniature 96-well sample plate, allowing the user to carry out immunological assays without a laboratory. The analyte is measured in a sandwich ELISA assay format combined with a sensitive electrochemiluminescence (ECL) detection method. Using the POC system, SEB, a major foodborne toxin, was detected at concentrations as low as 0.1 ng/ml. This is similar to the reported sensitivity of conventional ELISA. The open platform with simple modular fluid delivery automation design described here is interchangeable between detection systems, and because of its versatility it can also be used to automate many other LOC systems, simplifying LOC development. This new POC system is useful for carrying out various immunological and other complex medical assays without a laboratory and can easily be adapted for high-throughput biological screening in remote and resource-poor areas.

Multiple myeloma patients at peripheral blood stem cell harvest: restricted usage of TCR beta variable families

The immune systems of multiple myeloma patients are suppressed by the disease itself, and this immunosuppression is further enhanced by standard therapies. The aim of our study was to evaluate the effects of initial chemotherapy and a peripheral blood mobilisation regimen on T-cell population diversity. Reverse transcription-polymerase chain reaction (RT-PCR) with a new set of primers, in combination with capillary electrophoresis, was established. The methodology was used to analyse the relative expression of 27 T-cell receptor beta variable gene families (BV families) in multiple myeloma patients undergoing peripheral blood stem cell harvest. We found that the overall BV family usage in these patients was restricted; the relative expression of 10 BV families was significantly depressed in patients compared to healthy donors. These findings demonstrate that the preparative regimen for autologous stem cell transplantation affects the T-cell population in terms of the restriction of its T-cell receptor diversity.

Lab-on-a-chip for label free biological semiconductor analysis of staphylococcal enterotoxin B

We describe a new lab-on-a-chip (LOC) which utilizes a biological semiconductor (BSC) transducer for label free analysis of Staphylococcal Enterotoxin B (SEB) (or other biological interactions) directly and electronically. BSCs are new transducers based on electrical percolation through a multi-layer carbon nanotube-antibody network. In BSCs the passage of current through the conductive network is dependent upon the continuity of the network. Molecular interactions within the network, such as binding of antigens to the antibodies, disrupt the network continuity causing increased resistance of the network. For the fabrication of a BSC based detector, we combined several elements: (1) BSC transducers for direct detection, (2) LOC for flow through continuous measurements, (3) a digital multimeter with computer connection for data logging, (4) pumps and valves for fluid delivery, and (5) a computer for fluid delivery control and data analysis. Polymer lamination technology was used for the fabrication of a four layer LOC for BSC detection, the BSC on the chip is fabricated by immobilizing pre-functionalized single-walled carbon nanotubes (SWNTs)-antibody complex directly on the PMMA surface of the LOC. SEB samples were loaded into the device using a peristaltic pump and the change in resistance resulting from antibody-antigen interactions was continuously monitored and recorded. Binding of SEB rapidly increases the BSC electrical resistance. SEB in buffer was assayed with limit of detection (LOD) of 5 ng mL(-1) at a signal to baseline (S/B) ratio of 2. A secondary antibody was used to verify the presence of the SEB captured on the surface of the BSC and for signal amplification. The new LOC system permits rapid detection and semi-automated operation of BSCs. Such an approach may enable the development of multiple biological elements "Biological Central Processing Units (CPUs)" for parallel processing and sorting out automatically information on multiple analytes simultaneously. Such an approach has potential use for point-of-care medical and environmental testing.

Biological semiconductor based on electrical percolation

We have developed a novel biological semiconductor (BSC) based on electrical percolation through a multilayer three-dimensional carbon nanotube-antibody bionanocomposite network, which can measure biological interactions directly and electronically. In electrical percolation, the passage of current through the conductive network is dependent upon the continuity of the network. Molecular interactions, such as binding of antigens to the antibodies, disrupt the network continuity causing increased resistance of the network. A BSC is fabricated by immobilizing a prefunctionalized single-walled carbon nanotubes (SWNTs)-antibody bionanocomposite directly on a poly(methyl methacrylate) (PMMA) surface (also known as plexiglass or acrylic). We used the BSC for direct (label-free) electronic measurements of antibody-antigen binding, showing that, at slightly above the electrical percolation threshold of the network, binding of a specific antigen dramatically increases the electrical resistance. Using anti-staphylococcal enterotoxin B (SEB) IgG as a "gate" and SEB as an "actuator", we demonstrated that the BSC was able to detect SEB at concentrations of 1 ng/mL. The new BSCs may permit assembly of multiple sensors on the same chip to create "biological central processing units (CPUs)" with multiple BSC elements, capable of processing and sorting out information on multiple analytes simultaneously.

Electrical percolation-based biosensor for real-time direct detection of staphylococcal enterotoxin B (SEB)

Electrical percolation-based biosensing is a new technology. This is the first report of an electrical percolation-based biosensor for real-time detection. The label-free biosensor is based on electrical percolation through a single-walled carbon nanotubes (SWNTs)-antibody complex that forms a network functioning as a "Biological Semiconductor" (BSC). The conductivity of a BSC is directly related to the number of contacts facilitated by the antibody-antigen "connectors" within the SWNT network. BSCs are fabricated by immobilizing a pre-functionalized SWNTs-antibody complex directly on a poly(methyl methacrylate) (PMMA) and polycarbonate (PC) surface. Each BSC is connected via silver electrodes to a computerized ohmmeter, thereby enabling a continuous electronic measurement of molecular interactions (e.g. antibody-antigen binding) via the change in resistance. Using anti-staphylococcal enterotoxin B (SEB) IgG to functionalize the BSC, we demonstrate that the biosensor was able to detect SEB at concentrations as low as 5 ng/mL at a signal to baseline (S/B) ratio of 2. Such measurements were performed on the chip in wet conditions. The actuation of the chip by SEB is immediate, permitting real-time signal measurements. In addition to this "direct" label-free detection mode, a secondary antibody can be used to "label" the target molecule bound to the BSC in a manner analogous to an immunological sandwich "indirect" detection-type assay. Although a secondary antibody is not needed for direct detection, the indirect mode of detection may be useful as an additional measurement to verify or amplify signals from direct detection in clinical, food safety and other critical assays. The BSC was used to measure SEB both in buffer and in milk, a complex matrix, demonstrating the potential of electrical percolation-based biosensors for real-time label-free multi-analyte detection in clinical and complex samples. Assembly of BSCs is simple enough that multiple sensors can be fabricated on the same chip, thereby creating "Biological Central Processing Units (BCPUs)" capable of parallel processing and sorting out information on multiple analytes simultaneously which may be used for complex analysis and for point of care diagnostics.

Gold nanoparticle-based enhanced chemiluminescence immunosensor for detection of Staphylococcal Enterotoxin B (SEB) in food

Staphylococcal enterotoxins (SEs) are major cause of foodborne diseases, so sensitive detection (<1 ng/ml) methods are needed for SE detection in food. The surface area, geometric and physical properties of gold nanoparticles make them well-suited for enhancing interactions with biological molecules in assays. To take advantage of the properties of gold nanoparticles for immunodetection, we have developed a gold nanoparticle-based enhanced chemiluminescence (ECL) immunosensor for detection of Staphylococcal Enterotoxin B (SEB) in food. Anti-SEB primary antibodies were immobilized onto a gold nanoparticle surface through physical adsorption and then the antibody-gold nanoparticle mixture was immobilized onto a polycarbonate surface. SEB was detected by a "sandwich-type" ELISA assay on the polycarbonate surface with a secondary antibody and ECL detection. The signal from ECL was read using a point-of-care detector based on a cooled charge-coupled device (CCD) sensor or a plate reader. The system was used to test for SEB in buffer and various foods (mushrooms, tomatoes, and baby food meat). The limit of detection was found to be approximately 0.01 ng/mL, which is approximately 10 times more sensitive than traditional ELISA. The gold nanoparticles were relatively easy to use for antibody immobilization because of their physical adsorption mechanism; no other reagents were required for immobilization. The use of our simple and inexpensive detector combined with the gold nanoparticle-based ECL method described here is adaptable to simplify and increase sensitivity of any immunological assay and for point-of-care diagnostics.

High throughput analysis of TCR-beta rearrangement and gene expression in single T cells

Analysis of T-cell receptor beta chain (TCR-beta) rearrangement is essential to investigate T-cell responses in human autoimmune diseases, infection and cancer. Since the TCR-beta locus contains 55 variable (V) region gene segments, multiple assays have been necessary to determine TCR-beta rearrangements of individual T cells. We established a seminested rtPCR method for single T-cell analysis with two sets of degenerate primers covering 76 and 24% of the TCR-Vbeta genes, respectively. The specificity of the approach was validated by screening cDNAs obtained from T-cell clones (TCC) with defined TCR-beta rearrangement. We applied the method successfully to profile TCR-beta rearrangement of single T cells sorted from body fluids or dissected tissue. Concomitant analysis of other gene transcripts allowed determining phenotype and function of TCR-beta-defined single T cells. Our fast, cost-efficient and high throughput approach will facilitate studies on T-cell responses in human diseases.

Crystal structures of T cell receptor (beta) chains related to rheumatoid arthritis

The crystal structures of the Vbeta17+ beta chains of two human T cell receptors (TCRs), originally derived from the synovial fluid (SF4) and tissue (C5-1) of a patient with rheumatoid arthritis (RA), have been determined in native (SF4) and mutant (C5-1(F104-->Y/C187-->S)) forms, respectively. These TCR beta chains form homo-dimers in solution and in crystals. Structural comparison reveals that the main-chain conformations in the CDR regions of the C5-1 and SF4 Vbeta17 closely resemble those of a Vbeta17 JM22 in a bound form; however, the CDR3 region shows different conformations among these three Vbeta17 structures. At the side-chain level, conformational differences were observed at the CDR2 regions between our two ligand-free forms and the bound JM22 form. Other significant differences were observed at the Vbeta regions 8-12, 40-44, and 82-88 between C5-1/SF4 and JM22 Vbeta17, implying that there is considerable variability in the structures of very similar beta chains. Structural alignments also reveal a considerable variation in the Vbeta-Cbeta associations, and this may affect ligand recognition. The crystal structures also provide insights into the structure basis of T cell recognition of Mycoplasma arthritidis mitogen (MAM), a superantigen that may be implicated in the development of human RA. Structural comparisons of the Vbeta domains of known TCR structures indicate that there are significant similarities among Vbeta regions that are MAM-reactive, whereas there appear to be significant structural differences among those Vbeta regions that lack MAM-reactivity. It further reveals that CDR2 and framework region (FR) 3 are likely to account for the binding of TCR to MAM.

Simultaneous analysis of multiple staphylococcal enterotoxin genes by an oligonucleotide microarray assay

Staphylococcal enterotoxins (SEs) are a family of 17 major serological types of heat-stable enterotoxins that are one of the leading causes of gastroenteritis resulting from consumption of contaminated food. SEs are considered potential bioweapons. Many Staphylococcus aureus isolates contain multiple SEs. Because of the large number of SEs, serological typing and PCR typing are laborious and time-consuming. Furthermore, serological typing may not always be practical because of antigenic similarities among enterotoxins. We report on a microarray-based one-tube assay for the simultaneous detection and identification (genetic typing) of multiple enterotoxin (ent) genes. The proposed typing method is based on PCR amplification of the target region of the ent genes with degenerate primers, followed by characterization of the PCR products by microchip hybridization with oligonucleotide probes specific for each ent gene. We verified the performance of this method by using several other techniques, including PCR amplification with gene-specific primers, followed by gel electrophoresis or microarray hybridization, and sequencing of the enterotoxin genes. The assay was evaluated by analysis of previously characterized staphylococcal isolates containing 16 ent genes. The microarray assay revealed that some of these isolates contained additional previously undetected ent genes. The use of degenerate primers allows the simultaneous amplification and identification of as many as nine different ent genes in one S. aureus strain. The results of this study demonstrate the usefulness of the oligonucleotide microarray assay for the analysis of multitoxigenic strains, which are common among S. aureus strains, and for the analysis of microbial pathogens in general.

Vaccination with an immunodominant peptide of bovine type II collagen induces an anti-TCR response, and modulates the onset and severity of collagen-induced arthritis

T cell responses directed toward TCR-derived peptides have been shown to be an important regulatory mechanism of protection against autoimmunity. Here, we show that a naturally induced TCR-directed immune response can delay the onset of collagen-induced arthritis (CIA), an animal model of autoimmune rheumatoid arthritis in humans. DBA/1 mice were pretreated with an immunodominant peptide, p245-270, from bovine type II collagen (bCII) and were subsequently immunized with whole bCII for the induction of arthritis. The results showed that preactivation of p245-270-reactive cells delayed the onset and reduced the severity of CIA, compared with animals in the control group. Interestingly, the serum antibody response to bCII and the bCII-specific cytokine were not affected under these conditions. This result indicates that the observed protection was neither directly due to a lower antibody response nor due to the immune deviation of the anti-bCII T cell response. Furthermore, immunization with p245-270, but not bCII, induced a strong response to the B5 peptide, an immunodominant region of the TCR V(beta)8.2 (amino acids 76-101) that binds very strongly to I-A(q). These data suggest that at a critical phase in the loss of self-tolerance, an effective anti-TCR response, induced naturally, can regulate the pathogenic autoimmune response and thus may provide protection against autoimmunity.

T-cell-mediated autoimmunity: novel techniques to characterize autoreactive T-cell receptors

Histological samples of autopsy or biopsy tissue provide the best available evidence that autoreactive T cells are involved in the immunopathogenesis of many autoimmune diseases. However, morphology alone does not provide information on the antigen-specific T-cell receptor (TCR) of these cells, let alone on their antigen specificity. In this review article we discuss a number of emerging possibilities for identifying TCR sequences directly from biopsy tissue. We also review the methods for expressing presumably autoreactive TCR molecules and speculate on how the expressed TCR might be used to identify target antigens. Such information should eventually provide new insights into disease pathogenesis which lead to better therapies.

A DNA Spiegelmer to staphylococcal enterotoxin B

Bacterial staphylococcal enterotoxin B is involved in several severe disease patterns and it was therefore used as a target for the generation of biologically stable mirror-image oligonucleotide ligands, so called Spiegelmers. The toxin is a 28 kDa protein consisting of 239 amino acids. Since the full-length protein is not accessible to chemical peptide synthesis, a stable domain of 25 amino acids was identified as a suitable selection target. DNA in vitro selection experiments were carried out against the equivalent mirror-image D-peptide domain resulting in high affinity D-DNA aptamers. As expected, the corresponding enantiomeric L-DNA Spiegelmer showed comparable binding characteristics to the L-peptide domain. Moreover, the Spiegelmer bound the whole protein target with only slightly reduced affinity. Dissociation constants of both peptide-oligonucleotide complexes were measured in the range of 200 nM, whereas the Spiegelmer binding to the full-length protein was determined at approximately 420 nM. These data demonstrate the possibility to identify Spiegelmers against large protein targets by a domain approach.

Diagnostic role of tests for T cell receptor (TCR) genes

Rapid advances in molecular biological techniques have made it possible to study disease pathogenesis at a genomic level. T cell receptor (TCR) gene rearrangement is an important event in T cell ontogeny that enables T cells to recognise antigens specifically, and any dysregulation in this complex yet highly regulated process may result in disease. Using techniques such as Southern blot hybridisation, polymerase chain reaction, and flow cytometry it has been possible to characterise T cell proliferations in malignancy and in diseases where T cells have been implicated in the pathogenesis. The main aim of this article is to discuss briefly the process of TCR gene rearrangement and highlight the disorders in which expansions or clonal proliferations of T cells have been recognised. It will also describe various methods that are currently used to study T cell populations in body fluids and tissue, their diagnostic role, and current limitations of the methodology.

Simultaneous analysis of T cell clonality and cytokine production in rheumatoid arthritis using three-colour flow cytometry

In this study we examined the cytokine production by T cells and TCRVbeta subsets in peripheral blood (PB) and synovial fluid (SF) from six RA patients and PB from 10 normal subjects, using three-colour flow cytometry. In two RA subjects we assessed T cell clonality by RT PCR using TCRBV family-specific primers and analysed the CDR3 (complementarity determining region 3) length by GeneScan analysis. A high percentage of IFN-gamma- and IL-2- producing cells was observed among the PB T cells in both the RA patients and normal controls and among the SF T cells in RA patients. In contrast, the percentage of T cells producing IL-4 and IL-5 was small among PB T cells in both RA patients and normal controls and among SF T cells in RA patients. There was no significant difference in the production of IFN-gamma, IL-2 and IL-5 between the two compartments (PB and SF); however, there were significantly more IL-4-producing cells in SF. Molecular analysis revealed clonal expansions of four TCRBV families in SF of two of the RA patients studied: TCRBV6.7, TCRBV13.1 and TCRBV22 in one and TCRBV6.7, TCRBV21.3 and TCRBV22 in the second. These expansions demonstrated cytokine expression profiles that differed from total CD3+ cells, implying that T cell subsets bearing various TCR-Vbeta families may have the potential to modulate the immune response in RA patients.

Rheumatoid arthritis

Rheumatoid arthritis is a systemic inflammatory disorder that mainly affects the diarthrodial joint. It is the most common form of inflammatory arthritis, and has a substantial societal effect in terms of cost, disability, and lost productivity. Although the pathogenesis of rheumatoid arthritis remains incompletely understood, much insight into the cellular and molecular mechanisms involved has been gained in the past decade. On the basis of these insights, new therapies have been developed, and clinical trials have shown the efficacy of aggressive treatment of patients with active disease. In this review, we discuss improvements in our understanding of the pathophysiology of inflammatory synovitis in rheumatoid arthritis, and improvements in therapy for patients with the disorder. The past decade has seen substantial advances in these areas. Future studies will be directed at improving methods for early diagnosis and identification of patients with progressive disease, and at improving methods to identify candidates for subclasses of disease-modifying antirheumatic drugs (DMARDs). Long-term safety and efficacy data for the new DMARD agents and combination regimens will also further delineate efficacy and toxicity and thus the appropriate clinical context for use of these therapeutic approaches. The continuing elucidation of pathophysiological pathways relevant in rheumatoid arthritis, coupled with continuing advances in biotechnology and rational drug design, offer substantial hope for the continued development of increasingly potent and specific pharmacotherapy for treatment of rheumatoid arthritis.

Infectious agents in chronic rheumatic diseases

The possible role of infectious microorganisms in the disease process of both arthritis and autoimmunity continue to attract both basic and clinical researchers. However, proving a causal role for these suspects is a very difficult and complicated task. This article provides an update on various mechanisms in which microbes may play roles as inciting or perpetuating factors in the pathogenesis of connective tissue disease. It also focuses on current theories that specific microorganisms may play a role in rheumatoid arthritis and ankylosing spondylitis.

Potential biologic agents for treating rheumatoid arthritis

The encouraging clinical results observed in trials using anti-TNF therapy clearly warrant further studies to determine whether TNF inhibitors are capable of modifying the destructive component of this disease in long-term follow-up studies as well as to assess the safety of long-term use (see the article by Keystone in this issue). It is also reasonable to propose that interfering with the cytokine cascade earlier in the course of disease may be of even greater therapeutic benefit. As the pathogenetic mechanisms in RA are more clearly defined, especially in early disease and in those individuals destined to develop severe disease, the potential of other biologic agents to specifically inhibit these critical pathways may provide better treatments for our patients. Many potential targets in the immune-mediated process of RA are currently being rigorously evaluated in clinical trials. Use of combinations of biologic therapies, perhaps in human patients with RA, should be of considerable interest in future trials.

Dominant and shared T cell receptor beta chain variable regions of T cells inducing synovial hyperplasia in rheumatoid arthritis

Previously, we demonstrated the presence of at least two distinct subpopulations of patients with rheumatoid arthritis (RA) employing a cell-transfer experiment using severe combined immunodeficient (SCID) mice. One group of patients, whose T cells derived from the rheumatoid joints, induced synovial hyperplasia (SH) in the SCID mice (the positive group). The other group did not display the induction of SH (the negative group). TCR/Vbeta gene usage analysis indicated that some dominant T cell subpopulations were oligoclonally expanding only in the rheumatoid joints, and not in the periphery of the patients of the positive group. Moreover, these T cell subpopulations were not seen in the joints of patients in the negative group or in non-RA patients. In addition, the preferential uses of certain TCR/Vbetas (Vbeta8, Vbeta12, Vbeta13, and Vbeta14) genes were demonstrated in these T cells. In this study, to investigate whether these T cells are driven by a certain antigen(s), the third complementarity determining regions (CDR3s) of TCR/Vbeta, especially Vbeta8 and Vbeta14 PCR products, were cloned and sequenced. As a result, a dominant CDR3 sequence, CASS-PRERAT-YEQ, was found in Vbeta14+ T cells from the rheumatoid joint of a patient (Patient 1) of the positive group with a Vbeta14 skew. The identical CDR3 sequence also predominated in Vbeta14+ T cells from the rheumatoid joint of another patient (Patient 7) of the positive group with a Vbeta14 skew. In addition, in the patients (Patients 4, 7, 8) of the positive group with a Vbeta8 skew, other dominant CDR3 sequences, CASS-ENS-YEQ and CASS-LTEP-DTQ, were found as in the case of Vbeta14. However, no identical CDR3 sequences were detected dominantly in the joints of the patients in the negative group or in non-RA patients. A Vbeta14+ T cell clone (TCL), named G3, with the identical CDR3 sequence, CASS-PRERAT-YEQ, was isolated successfully from Patient 1, and cell transfer of G3 with autologous irradiated peripheral mononuclear cells induced SH in the SCID mice. Taken together, these results suggest that T cells inducing SH, thought to be pathogenic for RA, might be driven by a certain shared antigen(s).

Characterisation of T cell clonotypes that accumulated in multiple joints of patients with rheumatoid arthritis

OBJECTIVE

To investigate whether identical T cell clonotypes accumulate in multiple rheumatoid joints, the clonality of T cells that had infiltrated into synovial tissue (ST) samples simultaneously obtained from multiple joints of patients with rheumatoid arthritis (RA) was analysed.

METHODS

T cell receptor (TCR) beta gene transcripts, amplified by reverse transcription-polymerase chain reaction from ST and peripheral blood lymphocytes of five RA patients, were subjected to single strand conformation polymorphism analysis and DNA sequencing.

RESULTS

Approximately 40% of accumulated T cell clonotypes found in one joint of a patient were found in multiple joints in the same patient. Furthermore, identical amino acid sequences were found in TCR beta junctional regions of these clonotypes from different patients with at least one HLA molecule match.

CONCLUSIONS

The T cell clonotypes accumulating in multiple rheumatoid joints may be involved in the perpetuation of polyarthritis by reacting to antigens common to these multiple joints.

Experimental acute hematogenous osteomyelitis in mice. II. Influence of Staphylococcus aureus infection on T-cell immunity

A murine model of acute hematogenous osteomyelitis was used to study the immune response following Staphylococcus aureus infection and to examine the hypothesis that the bacteria may modify T-cell responses due to the production of bacterial enterotoxins with mitogenic or superantigenic activity. Lymph-node T cell-receptor expression was assessed with use of flow cytometry and reverse transcription-polymerase chain reaction techniques, and increased apoptosis (programmed cell death) in T-cell subsets was monitored. The expression and levels of circulating cytokines and T-cell cytokines within tissues surrounding the damaged area of the proximal tibia were also investigated. Analysis of T-cell receptors in experimental osteomyelitis revealed two distinct patterns of T-cell evolution during the disease. Certain T-cell subsets (Vbeta2, Vbeta3, Vbeta9, and Vbeta10) were activated and expanded during the first 24 hours after infection; they reached maximum levels 6 days after infection, followed by a return to pre-infection levels. In contrast, other T-cell subsets (Vbeta11, Vbeta12, Vbeta13, Vbeta14, and Vbeta16) contracted during the first 24 hours after infection, followed by expansion to a maximum level 9 days after infection. Activation and proliferation of T-cell subsets (notably Vbeta14 T cells) was followed by apoptosis, suggesting that staphylococcal bone infection caused superantigenic-like effects on the mouse immune system. Analysis of cytokine responses in local tissue revealed that the T-cell cytokines interleukin-2 and interferon-gamma showed a late and relatively short activation pattern compared with the inflammatory cytokines interleukin-1, interleukin-6, and tumor necrosis factor-alpha. The results suggest that Staphylococcus aureus bone infection may undermine the antibacterial immune response through downregulation of T-cell immunity and immune-cytokine production, which could increase the severity of the systemic infection and local osseous destruction that occur with acute hematogenous osteomyelitis.

T cell receptor gene in synovial tissues of rheumatoid arthritis

Rheumatoid arthritis is a chronic and destructive autoimmune joint disease characterized by inflammation of synovial tissue of unknown aetiology. Studies on TCR genes expressed by infiltrating T cells in synovial tissues have attempted to identify mechanism and specificity of the recruitment. T cell infiltrate in rheumatoid arthritis appears to be an association of a polyclonal non specific infiltrate with dominant clones or clonotypes. T cell repertoire in synovial tissue is biased compared to peripheral blood but no TCR V gene can be identified as commonly over-used. Comparison of motifs found in the CDR3 region of dominant clones from different studies has currently failed to identified a commonly motif. The fact that a number of dominant clones or clonotypes is present in different joints and at different times of the disease suggests a selective expansion of T lymphocytes in rheumatoid arthritis synovial membrane. Further investigations are needed to characterize the specificity of these dominant clonotypes.

T cell receptor peptide vaccination in rheumatoid arthritis: a placebo-controlled trial using a combination of Vbeta3, Vbeta14, and Vbeta17 peptides

OBJECTIVE

Restricted T cell receptor (TCR) gene usage has been demonstrated in animal models of autoimmune disease and has resulted in the successful use of TCR peptide therapy in animal studies. This clinical trial was undertaken to determine the safety and efficacy of a combination of Vbeta3, Vbeta14, and Vbeta17 TCR peptides in Freund's incomplete adjuvant (IFA) in patients with rheumatoid arthritis (RA).

METHODS

A double-blind, placebo-controlled, multicenter, phase II clinical trial was undertaken using IR501 therapeutic vaccine, which consists of a combination of 3 peptides derived from TCRs (Vbeta3, Vbeta14, and Vbeta17) in IFA. A total of 99 patients with active RA received either 90 microg (n = 31) or 300 microg (n = 35) of IR501 or IFA alone (n = 33) as a control. The study medication and placebo were administered as a single intramuscular injection (1 ml) at weeks 0, 4, 8, and 20.

RESULTS

Treatment with IR501 was safe and well tolerated. None of the patients discontinued the trial because of treatment-related adverse events. Efficacy was measured according to the American College of Rheumatology 20% improvement criteria. Using these criteria, patients in both IR501 dosage groups showed improvement in disease activity. In the most conservative analysis used to evaluate efficacy, an intent-to-treat analysis including all patients who enrolled, the 90-microg dosage group showed a statistically significant improvement compared with control patients at the 20-week time point after the third injection. Trends toward improvement were shown in both the 90-microg and the 300-microg dosage groups at week 24 after the fourth injection.

CONCLUSION

IR501 therapeutic vaccine therapy was safe and well tolerated, immunogenic, and demonstrated clinical improvement in RA patients. Additional clinical trials are planned to confirm and extend these observations.

T-cell receptor peptide vaccination in the treatment of rheumatoid arthritis

In several human T-cell-mediated autoimmune diseases and animal models of such illnesses, T-cell receptors (TCR) specific for antigens that initiate or perpetuate the disease share a limited number of variable region determinants. Vaccinations with peptides derived from over-represented TCRs are effective treatment for some of these disorders. RA is a chronic inflammatory disease in which there is prominent T-cell infiltration in the synovial lining layer. TCR V beta 3, V beta 14, and V beta 17 have been found to be over-represented among IL-2 receptor-positive T-cells from patients with RA. A phase II clinical trial in RA, using a combination of three peptides derived from V beta 3, V beta 14, and V beta 17, has yielded promising results. Larger clinical efficacy and safety studies must be performed to determine if TCR peptide vaccination will become a viable treatment alternative for patients with RA.

Role of the T cell receptor in idiopathic thrombocytopenic purpura (ITP)

During the past few decades a number of studies has described T cell defects and attempted to elucidate their role in the pathogenesis of idiopathic thrombocytopenic purpura (ITP). Some studies implicate T cells as potential initiators of autoantibody production in ITP. However, only a few of these have studied the role that the T cell receptor may play in the pathogenesis of ITP. In a variety of autoimmune syndromes interest has focused on the alpha- and beta-chains of the T cell receptor. Deviations from the normal T cell receptor gene usage have been reported in rheumatoid arthritis, systemic lupus erythaematosus and multiple sclerosis. Usually, these studies have shown a restricted heterogeneity of T cell receptor variable gene usage. The studies on the T cell receptor in ITP have included a limited number of patients, which makes it difficult to evaluate the significance of the role that the T cell receptor may play in the pathogenesis of ITP. Further studies are warranted.

Heteroclitic proliferative responses and changes in cytokine profile induced by altered peptides: implications for autoimmunity

Productive engagement of T cell receptors (TCRs) by cognate ligand (major histocompatibility complex plus peptide) leads to proliferation, differentiation, and the elaboration of effector functions. Altered peptides generated by single amino acid substitutions in the antigenic peptide have diverse effects on the outcome of the T cell response. We have generated an altered peptide (Q144) from an autoantigenic peptide of myelin proteolipid protein 139-151 by a single amino acid substitution (from tryptophan to glutamine) in the primary TCR contact at position 144 that is capable of inducing CD4(+) T cell responses in H-2(s) mice. By using a Q144-specific T cell clone (Q1.1B6), we see a hierarchy in T cell proliferation and cytokine production with various position 144 substituted peptides and have identified a peptide (L144) that hyperstimulates this T cell clone. In contrast to Q144, L144 induces maximal proliferation at 7 logs lower antigen concentration, induces greater cell death at higher antigen dose, and induces the secretion of cytokines not detected following stimulation with the cognate ligand. This heteroclitic T cell response associated with changes in cytokine profile was observed with several other T cell clones of different specificities. The L144 peptide also induces costimulation independent proliferation and cytokine production from the Q1.1B6 T cell clone. We describe this as a superagonist response. Such responses may have a role in the initiation of autoimmunity by promoting a proinflammatory environment following ligation of a cross-reactive TCR on autoreactive T cells.

Synovial fibroblasts as target cells for staphylococcal enterotoxin-induced T-cell cytotoxicity

Rheumatoid arthritis (RA) is a chronic autoimmune disease of unknown aetiology. Recently, superantigens have been implied in the pathogenesis of RA. Superantigens activate a large fraction of T cells leading to the production of cytokines and proliferation. In addition, superantigens direct cellular cytotoxicity towards major histocompatibility complex (MHC) class II-expressing cells. There is now increasing evidence that cytotoxic T cells may be involved in the pathogenesis of RA. In the inflamed synovia class II-positive synovial fibroblasts (SFC) are found. In the present study it was tested whether MHC class II-positive SFC serve as target cells for superantigen-induced cellular cytotoxicity. SFC were stimulated with interferon-gamma to express class II antigens, then they were cultivated in the presence of CD4-positive T cells with or without staphylococcal enterotoxins (SE). Cytotoxicity of T cells was measured as release of lactate dehydrogenase from SFC. Specific cytotoxicity was only found in the presence of class II-positive SFC depending on the dose of SE. Maximum lysis was seen after 20 hr. T-cell cytotoxicity was inhibited by antibodies to MHC class II antigens. The data suggest that class II-positive SFC not only function as accessory cells for SE-mediated T-cell proliferation and interleukin-2 production but may also be the targets of superantigen-mediated cellular cytotoxicity.

T cell receptor clonotypes in skin lesions from patients with systemic lupus erythematosus

Systemic lupus erythematosus is an autoimmune disease characterized by the presence of autoantibodies and by lymphocytic infiltration into lesions at several sites such as skin, kidney, and other organs. Immunohistologic studies have clarified that the majority of lymphocytes in the skin are CD4+ alphabeta T cells. In the present work, to clarify the pathologic role of T cells in the skin of systemic lupus erythematosus patients, we analyzed T cell receptor (TCR) clonotypes of T cells infiltrating into skin lesions. TCR Vbeta gene transcripts from T cells from discoid lesions of the skin and peripheral blood lymphocytes of four systemic lupus erythematosus patients were amplified by reverse transcriptase polymerase chain reaction. Southern blot analysis of polymerase chain reaction product demonstrated the heterogeneous TCR Vbeta repertoire of T cells in the skin of systemic lupus erythematosus. Single-strand conformation polymorphism analysis showed several distinct bands for smears of most TCR Vbeta genes from T cells infiltrating the skin, whereas smears with few bands were found for all TCR Vbeta genes from peripheral blood lymphocytes of the same patients. The number of bands encoding each TCR Vbeta gene from the skin was significantly higher compared with peripheral blood lymphocytes. Sequencing analysis showed a Leucine-X-Glycine amino acid motif at position 96-98 in the CDR3 region at the frequency of 23-24% in skin-accumulated T cells from two patients, whereas the frequency of this motif in peripheral T cells was only 0-3%, indicating limited T cell epitopes. In conclusion, T cells infiltrating into the skin of systemic lupus erythematosus patients might recognize restricted T cell epitopes on autoantigens and trigger the autoimmune reaction in skin lesions.

Limited T cell receptor Vbeta-chain repertoire of liver-infiltrating T cells in autoimmune hepatitis

BACKGROUND/AIMS

To characterize the cellular immune reactions in autoimmune hepatitis, the T cell receptor repertoire of liver-infiltrating and circulating T cells was studied.

METHODS

Nucleic acids of liver-tissue and peripheral blood-derived T cells from 12 patients with untreated autoimmune hepatitis, four patients with chronic hepatitis C and three patients with toxic liver injury were extracted and analysed using a semiquantitative RT-PCR with a panel of T cell receptor Vbeta family specific primers. After agarose gel electrophoresis, the distribution of T cell receptor (TCR) Vbeta molecules was assessed by densitometry. Furthermore, results were compared to the TCR Vbeta distribution of 10 healthy blood donors.

RESULTS

Four of 12 patients with untreated autoimmune hepatitis but no patients with chronic hepatitis C and toxic liver injury showed a significant overexpression of TCR Vbeta3 (17.8% +/- 2.6% vs. 9.3% +/- 4.6%; p = 0.01) and three an overexpression of Vbeta13.1 (14.6% +/- 2.3% vs. 6.6% +/- 3.5%; p = 0.02) molecules compared to the TCR Vbeta-distribution in healthy blood donors. In addition, Vbeta3+ T cells were found enriched in the liver tissue compared to autologous peripheral blood in three autoimmune hepatitis patients (15.3% +/- 7.0% vs. 5.2% +/- 3.1%; L/B ratio: 2.9), while Vbeta13.1+ T cells were enriched in the liver tissue from one of three patients with overexpression.

CONCLUSIONS

In autoimmune hepatitis a disease specific compartmentalisation of TCR Vbeta3+ T cells was observed in the liver tissues. Although their specificity was unknown, this might indicate that these infiltrating T cells could have relevance for abnormal immunoregulation.

TCR vbeta usage of TSH receptor-specific CD4+ T cells in Graves' disease patients and healthy humans

Healthy humans have CD4+ T cells specific for self-components. Since autoreactive T cells in autoimmune patients may use a limited number of TCR V-region genes, we investigated here whether this also occurs for the potentially autoreactive CD4+ cells present in healthy persons. We studied CD4+ cells specific for human TSH receptor (TSHr) sequences, that are present with high frequency in healthy subjects and, as expected, in Graves' disease (GD) patients. We used short-term CD4+ cell lines propagated from four GD patients and five healthy subjects by cycles of stimulation with a pool of overlapping synthetic peptides corresponding to the putative extracellular parts of the TSHr sequence. The lines recognized the pool of TSHr peptides specifically and vigorously. Their epitope repertoire had been characterized previously: each line recognized one or a few TSHr peptides, different for each subject. We determined their TCR Vbeta usage by a semi-quantitative reverse transcriptase PCR assay, using primers specific for each known human Vbeta region family, in conjunction with a constant region primer. Six lines preferentially used one Vbeta family (42-94%), different for each line. In all lines, three or less Vbeta families accounted for approximately 60% or more of the Vbeta usage. Different Vbeta regions were used by each subject. There was no obvious difference between the Vbeta usage of the lines from GD patients and healthy controls. These results suggest that a limited pool of potentially autoreactive T cells survives clonal deletion. The pathogenic CD4+ cells involved in autoimmune diseases are likely recruited from that pool, since they have similar characteristics of epitope and TCR repertoire as the CD4+ cells specific for the same autoantigen in healthy subjects.

Analysis of TCRAV and TCRBV repertoires in healthy individuals by microplate hybridization assay

We have developed an adaptor ligation PCR-based microplate hybridization assay (MHA) for analysis of T cell receptor alpha chain variable region (TCRAV) and T cell receptor beta chain variable region (TCRBV) repertoires. Forty three TCRAV and thirty eight TCRBV-specific probes were immobilized onto microplate wells in water-soluble carbodiimide. After hybridization of 5'-biotinylated PCR products, quantitative ELISA was carried out and followed by automated colorimetric reading. The conditions for immobilization and hybridization were optimized using representative TCRBV-specific probes. The sensitivity of MHA allows us to detect as low as 40 pg of biotinylated PCR products. The frequencies of individual V segments obtained by MHA were consistent with those obtained by FACS analysis and reverse dot blot assays. Analysis of the entire TCRAV and TCRBV repertoires could be done using a single 96-well plate, and completed in less than 6 h. Simplicity and reproducibility of this method make it suitable for routine laboratory use. The expression of TCRAV and TCRBV segments was next studied in peripheral blood mononuclear cells (PBMC) of 14 healthy donors using the newly developed MHA method. TCRAV8S1, TCRAV23S1, TCRBV2S1, TCRBV3S1, TCRBV4S1, and TCRBV6S5 were highly expressed in PBMC. Further, the TCRAV repertoires among individuals were less variable compared to the TCRBV repertoires. Interestingly, considerable variations in the expression levels of BV3S1, BV4S1, and BV17S1 were observed among individuals. One polymorphic site was found at the coding region of BV4S1, and there were two alleles. These results suggest that variable expression among individuals may be associated with unknown allelic polymorphism in coding and/or regulatory regions of these TCRBV segments, or with disparity in HLA genes.

Multiple mechanisms support oligoclonal T cell expansion in rheumatoid synovitis

BACKGROUND

The synovial T cell infiltrate in rheumatoid arthritis (RA) is diverse but contains clonally expanded CD4+ populations. Recent reports have emphasized that RA patients have a tendency to develop CD4+ T cell oligoclonality which also manifests in the peripheral blood. Clonal dominance in the tissue may thus result from antigen specific stimulation in the synovial membrane or may reflect the infiltration of expanded clonotypes present throughout the lymphoid system. We have explored to what extent clonal populations amongst tissue CD4+ T cells display joint specificity as defined by their restriction to the joint, their persistence over time, and their expression of markers indicative for local activation.

MATERIALS AND METHODS

Matched samples of peripheral blood and synovial fluid or synovial tissue were collected from 14 patients with active RA and CD4+ IL-2R+ and CD4+ IL-2R- T cells from both compartments were purified. Clonal populations of CD4+ T cells were detected by RT-PCR amplification of T cell receptor (TCR) transcripts with BV and BJ specific primers followed by size fractionation and direct sequencing of dominant size classes of TCR transcripts.

RESULTS

Clonal CD4+ T cells were detected in the synovial fluid and synovial tissue of all patients. All patients carried synovial clonotypes that were undetectable in the blood but were present in independent joints or at several non-adjacent areas of the same joint. These joint restricted CD4+ clonotypes were generally small in size, were preferentially found in the IL-2R+ subpopulation, and persisted over time. A second type of clonogenic T cells in the synovial infiltrate had an unrestricted tissue distribution and was present at similar frequencies amongst activated and nonactivated T cells in the blood and affected joints. Ubiquitous clonotypes isolated from two different patients expressed sequence homologies of the TCR beta chain.

CONCLUSIONS

Two types of expanded CD4+ clonotypes contribute to the T cell infiltrate in rheumatoid synovitis. Differences in the distribution pattern and in molecular features suggest that distinct mechanisms are supporting the clonal outgrowth of these two groups of clonotypes. Clonally expanded T cells restricted to the joint but present in several independent joints appear to respond to locally residing antigens. Clonogenic cells with an unrestricted distribution pattern and widespread activation in the blood and tissue may react to a different class of antigens which appear to be shared by multiple patients. T cell recognition in RA may be involved at several different levels and may be related to more than one pathomechanism.

T cell receptor alpha-chain and beta-chain junctional region homology in clonal CD3+, CD8+ T lymphocyte expansions in Felty's syndrome

OBJECTIVE

Up to 42% of patients with Felty's syndrome (FS) have peripheral blood expansions of CD3+,CD8+ large granular lymphocytes (LGLs). The aim of this study was to determine whether the T cell receptor (TCR) alpha- and beta-chain sequences of these expansions from different patients have features in common that would support the hypothesis of an antigen-driven process.

METHODS

Extraction of RNA from peripheral blood lymphocytes followed by synthesis of complementary DNA, inverse polymerase chain reaction (PCR) with TCR-specific primers, bacteriophage transformation, and sequencing of PCR products.

RESULTS

Structural analysis of TCR beta-chain usage in such patients demonstrated a junctional region motif comprising the amino acids -LG- or -RG- in 7 of 14 clonal sequences and the motif -GXG- in 8 of 14. A biased alpha-chain junctional region usage of a hydrophobic and/or basic amino acid at position 2 was seen in 5 of 8 expanded sequences. These features differed significantly from control sequences.

CONCLUSION

Given current models of TCR-peptide-major histocompatibility complex interaction, these observations are consistent with an antigen-driven, rather than a superantigen-driven, process in at least a subgroup of patients with FS.

Analysis of T-cell receptor Vbeta repertoire in liver-infiltrating lymphocytes in chronic hepatitis C

BACKGROUND/AIMS

To examine the T-cell repertoire which is involved in the immunopathogenesis of chronic hepatitis, we analyzed the T-cell receptor Vbeta gene usage in liver-infiltrating lymphocytes by reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemical technique.

METHODS

Complementary DNA was synthesized from RNA which was extracted from 26 liver biopsy specimens and from peripheral blood lymphocytes from eight subjects, and amplified by RT-PCR. Radioactivity of each amplified product using 32P-labeled primers was measured and the percentage of each Vbeta expression was calculated.

RESULTS

The mean frequency of Vbeta5.1 (11.1%) in liver-infiltrating lymphocytes of chronic hepatitis C was highest among those of all Vbeta regions, and was significantly higher than that in both peripheral blood lymphocytes of chronic hepatitis C and liver-infiltrating lymphocytes of chronic hepatitis B. In the immunohistochemical analysis, Vbeta5.1-positive cells were mostly observed in portal areas where inflammatory reactions occurred. The sequences of the complementarity determining region (CDR)3 on T-cell receptor expressing Vbeta5.1 were examined in six patients with chronic hepatitis C. The sequences were similar to each other and all had one common amino acid (valine) irrespective of different HLA haplotype.

CONCLUSIONS

These data suggest that Vbeta5.1-positive cells are preferentially accumulated in the liver of chronic hepatitis C and are involved in the immunopathogenesis of the disease. Sequence analysis showed that Vbeta5.1-positive cells recognize a common conventional antigen and valine recognized at the same position of the CDR3 may be a key residue in determining an antigen/major histocompatibility complex contact point.

Quantitative analysis of the usage of human T cell receptor alpha and beta chain variable regions by reverse dot blot hybridization

We previously developed an adaptor ligation-mediated PCR method to amplify the T cell receptor (TCR) cDNA pools. In the present study we applied reverse dot blot hybridization to PCR-amplified specimens for quantitative analysis of the usage of TCR alpha and beta chain variable (V) region. 44 VA sequence-specific oligonucleotide probes (SSOPs) and 38 VB SSOPs were synthesized corresponding to unique sequences of VA and VB subfamilies. Peripheral blood lymphocytes of ten healthy donors and five T cell clones established from bone marrow cells were examined for VA and VB usage using this method. The results were consistent with those obtained by a colony hybridization method and those by immunofluorescence staining using monoclonal antibodies to VA and VB. Thus, reverse dot blot hybridization for TCR V(alpha) and Vbeta is a new, easy and dependable technique useful for analysis of VA and VB usage by human T cells.

T-cell receptor beta chain variability in bone marrow and peripheral blood in severe acquired aplastic anemia

Aplastic anemia (AA) is characterized by multilineage bone marrow failure of unknown etiology. In order to assess the role of immune-mediated mechanisms in hematopoietic suppression, we examined the diversity of T lymphocyte repertoire in terms of variable (V) gene segment usage of the T cell receptor (TCR) beta chain in bone marrow and peripheral blood of six patients with severe untreated AA. Expression of transcripts encoding Vbeta1-Vbeta24 subfamilies was analyzed by reverse transcription-polymerase chain reaction (RT-PCR). The results revealed that T lymphocytes in AA utilize highly diverse segments of the beta chain loci. Over the heterogenous Vbeta expression background, transcripts encoding Vbeta3, Vbeta20, Vbeta21, and Vbeta22 subfamilies were enhanced by at least threefold in 5 of 6 patients as compared to normal samples, but a different transcript species was over expressed in each patient. To evaluate clonality of T cells, size diversity within the complementarity determining region 3 (CDR3) and usage of TCRbeta joining (J) gene segments were analyzed in PCR products specific for each of the 24 Vbeta subfamilies. We found that the majority of transcripts display normal CDR3 size patterns, as is characteristic of polyclonal populations. Nevertheless, one or two predominating junctional rearrangements were observed in each patient. They were identified in Vbeta5, Vbeta7, Vbeta8, Vbeta13, Vbeta15, Vbeta16, and Vbeta23 transcripts, which differed from patient to patient and did not correspond to transcripts with an abnormally high expression level. Our results demonstrate that T cell repertoire in AA is random with respect to the TCR beta chain. Unique rearrangements detected in the CDR3 region are suggestive of a limited process of an antigen-driven (oligo)clonal T cell expansion which may take place over the overwhelmingly polyclonal repertoire of T lymphocytes at the onset of severe AA.

High frequencies of identical T cell clonotypes in synovial tissues of rheumatoid arthritis patients suggest the occurrence of common antigen-driven immune responses

OBJECTIVE

To investigate T cell antigen receptor (TCR) clonotypes in rheumatoid arthritis (RA) lesions.

METHODS

Reverse transcriptase-polymerase chain reaction with TCR V beta family-specific primers and subsequent single-strand conformation polymorphism (SSCP) analysis were performed. Direct nucleotide sequencing was also conducted.

RESULTS

A distinct clonal expansion of T cells was observed in the synovium. Furthermore, identical bands in samples of different areas of the same lesion were obtained by SSCP analysis. Nucleotide sequencing revealed that T cell clonotypes of identical mobility on SSCP analysis had the same nucleotide sequence and thus were identical clones. In 6 RA patients, 60-100% of the expanded T cell clonotypes had identical migration patterns in 2 different samples, indicating that this percentage represents commonly existing T cell clonotypes in the affected joint. Furthermore, the J beta 2.1 gene segment was used predominantly by the TCR V beta clonotypes that commonly expanded in the different portions of the same joint.

CONCLUSION

These results suggest that the immune response in RA is not random, but rather is driven by common stimuli.

Limited heterogeneity of rearranged T cell receptor V alpha and V beta transcripts in synovial fluid T cells in early stages of rheumatoid arthritis

OBJECTIVE

The identification of activated T cells in synovial fluid and synovium, and the association of rheumatoid arthritis (RA) with specific HLA-DR restriction elements, strongly suggest that these T cells play a critical role in the etiology and pathogenesis of RA. Analysis of the T cell receptor (TCR) repertoire in the early stages of RA might be an approach to identify those T cells involved in the initiation and/or perpetuation of the disease.

METHODS

TCR V alpha and V beta transcripts of synovial T cells, sampled at the early stages of RA, were amplified by reverse transcriptase-polymerase chain reaction. HLA-DR subtyping was determined by serologic analysis and dot-blot hybridization of polymerase chain reaction amplification products using digoxigenin-labeled, sequence-specific oligonucleotide probes.

RESULTS

Our findings showed a limited heterogeneity of V alpha and V beta TCRs in synovial fluid T cells, and a preferential usage of TCR V alpha 17 in early RA. In contrast, in the later stages of RA, a more polyclonal TCR V alpha and V beta gene usage was observed.

CONCLUSION

Our results support the view that induction of RA is driven by an oligoclonal immune response to an unknown antigen. These findings also suggest a pathogenetic role for V alpha 17 T cells in the early stages of RA.

T cell receptor (TCR) repertoire in alloimmune responses

A large number of alloantigenic determinants could be generated by both the direct and indirect alloantigen presentation pathways. Hence, a heterogeneous population of T cells expressing a wide variety of receptors would be expected to respond to this diverse array of alloantigenic determinants. However, T cells expressing highly restricted T cell receptor (TCR) variable genes have been reported in a variety of alloimmune responses. A similar phenomenon has been observed in a wide variety of other immune responses, from those induced by superantigens, to very specific responses induced by a single peptide presented by a single MHC molecule. Given this scenario, the limited number of T cell clones which dominate an allograft rejection response, or for that matter an autoimmune response or a tumor specific response, could be therapeutically targeted by virtue of the selected TCR expression.

Functional analysis of synovial fluid and peripheral blood T cells from patients with rheumatoid arthritis

Rheumatoid arthritis is a T cell-mediated autoimmune disease. The lack of knowledge of the involved target antigens severely hampers research on relevant T cells in patients. Here we describe the functional analysis of freshly isolated T cells from the peripheral blood and the site of the lesion (synovial fluid or synovial membrane) of patients with rheumatoid arthritis. Healthy donors and osteoarthritis patients served as controls. Using various polyclonal stimuli, we analyzed CD4+ T cells with respect to proliferation and their ability to produce lymphokines. Our data show that lesion-derived CD4+ T cells of patients with rheumatoid arthritis are severely defective in proliferation and lymphokine (interleukin-2, interleukin-4, tumor necrosis factor-alpha, interferon-gamma) production. This activation defect was most pronounced at lower cell densities and was present in both synovial fluid derived and synovial membrane derived CD4+ T cells of all patients tested. No difference was found between responses of synovial fluid derived CD4+ T cells from osteoarthritis patients and those observed with peripheral blood derived T cells from all groups. The observed defect in lesion-derived CD4+ T cells from rheumatoid arthritis patients was not due to the effect of inflammatory factors in the synovial fluid because preincubation with synovial fluid could not induce a similar defect in control T cells. Together, our data show a rheumatoid arthritis specific, general defect in the activation of lesion-derived CD4+ T cells.

Transfer of rheumatoid arthritis into severe combined immunodeficient mice. The pathogenetic implications of T cell populations oligoclonally expanding in the rheumatoid joints

To investigate the pathogenicity of T cells infiltrating in the rheumatoid joints, mononuclear cells (MNC), predominantly T cells, isolated from either synovial fluid or synovial tissues of the patients with RA were transferred into severe combined immunodeficient (SCID) mice by intraarticular injections. According to our observations in this experimental system, patients with RA could be classified into at least two groups. In one group of patients, the infiltrating MNC induced synovial hyperplasia in the recipient SCID mice (the positive group). Whereas, in the other group no synovial hyperplasia was observed (the negative group). The induction of synovial hyperplasia observed in the positive group was prevented by an anti-human CD3 antibody (OKT3), indicating T cell mediation. Analysis of T cell receptor (TCR) V beta usage by reverse transcriptase polymerase chain reaction in the infiltrating MNC transferred into SCID mice revealed a marked skew towards the preferential use of certain V beta genes, which was not seen in the peripheral blood MNC, in only the positive group. The patterns of TCR/V beta skew were not uniform among the patients. The analysis of the PCR-amplified genes of such skewed TCR/ V beta by single strand conformational polymorphism showed distinct bands, indicating that the T cell populations expanding in rheumatoid joints of the positive group were oligoclonal. Furthermore, the enrichment of the T cell populations expressing such skewed TCR/V beta by in vitro stimulation of peripheral blood MNC of the patients with the relevant superantigen enabled the induction of synovial hyperplasia in the SCID mice. These results suggest that the pathogenic T cells could be activated locally in rheumatoid joints by certain antigens in some, but not in all patients with RA.