Conserved motifs in rheumatoid arthritis synovial tissue T-cell receptor beta chains

Conformational dimorphism of self-peptides and molecular mimicry in a disease-associated HLA-B27 subtype

An interesting property of certain peptides presented by major histocompatibility complex (MHC) molecules is their acquisition of a dual binding mode within the peptide binding groove. Using x-ray crystallography at 1.4 A resolution, we show here that the glucagon receptor-derived self-peptide pGR ((412)RRRWHRWRL(420)) is presented by the disease-associated human MHC class I subtype HLA-B*2705 in a dual conformation as well, with the middle of the peptide bent toward the floor of the peptide binding groove of the molecule in both binding modes. The conformations of pGR are compared here with those of another self-peptide (pVIPR, RRKWRRWHL) that is also displayed in two binding modes by HLA-B*2705 antigens and with that of the viral peptide pLMP2 (RRRWRRLTV). Conserved structural features suggest that the N-terminal halves of the peptides are crucial in allowing cytotoxic T lymphocyte (CTL) cross-reactivity. In addition, an analysis of T cell receptors (TCRs) from pGR- or pVIPR-directed, HLA-B27-restricted CTL clones demonstrates that TCR from distinct clones but with comparable reactivity may share CDR3alpha but not CDR3beta regions. Therefore, the cross-reactivity of these CTLs depends on TCR-CDR3alpha, is modulated by TCR-CDR3beta sequences, and is ultimately a consequence of the conformational dimorphism that characterizes binding of the self-peptides to HLA-B*2705. These results lend support to the concept that conformational dimorphisms of MHC class I-bound peptides might be connected with the occurrence of self-reactive CTL.

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.

Toxic shock syndrome toxin-1 accelerated collagen-induced arthritis in mice

The aim of this study was to explore the roles of toxic shock syndrome toxin-1 (TSST-1) in collagen-induced arthritis (CIA). DBA/1 mice were immunized with type II collagen (CII) and treated with TSST-1. Intraperitoneal and intravenous injections of TSST-1 aggravated CIA, enhancing its incidence and severity. CIA was accompanied by an increase in anti-CII IgG Ab levels. Intraperitoneal administration with TSST-1 enhanced IFN-gamma, TNF-alpha, and IL-4 production in DBA/1 mice. We discovered the mRNA expressions of IFN-gamma, IL-2, TNF-alpha, IL-1beta, and iNOS in spleen cells stimulated with TSST-1 in vitro. However, IL-12 and IL-4 mRNA expression were seen constitutively without stimulation. Only a little increase of IL-12 and IL-4 mRNA expression was seen at 2-3 h after treatment with TSST-1. Our experiments demonstrated that CIA was aggravated by the treatment with TSST-1, which may have induced various proinflammatory cytokines and the production of both Th1 and Th2 cytokines.

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.

New therapeutic targets for rheumatoid arthritis

New insights into the pathogenesis of rheumatoid arthritis (RA) and consequently new targets of therapy are covered in a broad overview fashion. Short-term significant beneficial effect on RA disease activity has been established in a small but rapidly growing number of double-blind placebo-controlled trials now including recombinant human IL-1 receptor antagonist, chimeric (mouse/human) monoclonal antibodies (mAb) against TNF alpha (cA2), humanised (human/mouse) anti-TNF alpha mAb (CDP571) and recombinant human TNF-receptor-Fc fusion protein (TNFR:Fc). Placebo-controlled trials of anti-T cells agents such as chimeric anti-CD4 mAb (cM-T412) and anti-CD5 immunoconjugate, did not demonstrate clinical benefit. A placebo-controlled study of the anti-T cell derived cytokine IL-2 (DAB486IL-2) showed only modes clinical improvement. Other anti-T cell approaches such as autologous T cell vaccination and induction of tolerance by oral type II collagen have been unsuccessful. The one controlled trial with an anti-inflammatory cytokine, recombinant human IFN-gamma, showed modest clinical benefits. Controlled trials with IL-4 and IL-10 and with anti-adhesion molecules are awaited.

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.

Structural motifs in rheumatoid T-cell receptors

The linkage of rheumatoid arthritis (RA) to HLA-DR haplotypes, high levels of HLA-DR expression, and T-cell infiltration in the joints, indicate a central role for the interaction of T-cell receptors (TCR) with antigen (Ag) + major histocompatibility complex (MHC) complexes in pathogenesis. Receptor analysis in RA has uncovered a restricted heterogeneity of TCR transcripts, suggesting an antigen-driven response. We analyzed the sequence and structural features of RA-associated TCRs in light of the recently published TCR crystal structures. The surface-exposed residues of the third complementarity-determining region (CDR3s) showed preferential use of certain amino acid residues when sequences derived from synovial fluid or tissue were compared with those derived from peripheral blood, particularly for alpha chains. Sequence alignment of oligoclonal synovial TCR CDR3s revealed groupings with similar CDR3 lengths and amino acid compositions, which suggests shared antigen recognition. Given the limitations of analyzing TCR sequences without knowing their structures, we developed several in vivo-activated synovial-tissue Vbeta17 + RA T-cell clones. Two Vbeta17/V alpha7 clones with different CDR3 sequences were analyzed by molecular modeling. Although distinct topologic features were seen, a central patch of residues with similar chemical and geometric characteristics was present in both. Electrostatic maps revealed similar binding surfaces of both alpha domains and central patches, with differences in the beta domains. This suggests that an alpha-domain-focused binding trajectory would allow shared antigen recognition by these TCRs. These studies support recognition of a limited diversity of Ag + MHC complexes by synovial RA TCRs.

T cell receptor (V beta) bias in the response of rheumatoid arthritis synovial fluid T cells to connective tissue antigens

T cell receptor (V beta) use in the response to type II collagen and cartilage proteoglycans was analysed in peripheral blood and synovial fluid T cells from RA patients. T cells from RA patients with an immune response to connective tissue antigens, and paired PB and SF samples were stimulated in vitro with type II collagen, high density aggrecan proteoglycans (PG), and the T cell mitogen concanavalin A. After short term culture, mRNA was extracted from cells and a reverse transcription-polymerase chain reaction was performed, using primers specific for eight TCR V beta determinants. Blood cells stimulated with ConA generated strong bands with virtually all the V beta primers tested, but the TCR (V beta) expression by SF T cells stimulated with mitogen was biased, suggesting a selection process during joint infiltration. The V beta phenotypes of cells responding to PG was restricted in individual RA patients, but the pattern of V beta use in the the RA population was not consistent. In contrast, the V beta phenotypes of SF cells responding to CII was highly biased in both individual patients and the RA population, with V beta 14, V beta 17, and V beta 8 phenotypes predominant. We conclude that the T cell response to connective tissue antigens is restricted compared with mitogen stimulation, with the highest degree of TCR bias seen in the response of SF T cells to stimulation with type II collagen.

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.

Immunopathogenesis of juvenile rheumatoid arthritis: role of T cells and MHC

Juvenile rheumatoid arthritis (JRA) is defined as chronic arthritis of unknown etiology appearing in patients less than 16 years of age. The disease is heterogeneous and is classified as pauciarticular, polyarticular, or systemic-onset disease. A few lines of evidence suggest that T cells are involved in the pathogenesis of the disease. T cells infiltrating the synovial membrane bear markers of activation and produce cytokines. The association of particular subtypes of JRA with certain HLA class II alleles provides strong evidence in favor of T cell involvement through an HLA-peptide-T cell receptor complex. Limited data from a few patients with JRA on T cell receptor transcripts from synovial membrane or synovial fluid cells point towards oligoclonality. This further supports the concept that T cells infiltrating the synovial membrane or extravasating into synovial fluid in patients with JRA reflect antigen-driven T cell proliferation.

Environmental and genetic factors shape the human T-cell receptor repertoire

Both environmental and genetic factors combine to shape the TCR repertoire as measured by V gene usage. These factors may result in dramatic shifts in normal subjects, which cannot be discounted when studies are performed in patients with disease. Future studies need to explore further examples of genetic and environmental factors that shape the TCR repertoire to understand the full extent of variation in a normal population and the mechanisms involved. Some of these mechanisms may also apply to TCRG, TCRD, and immunoglobulin loci. Certainly variations in the efficiency of V(D)J rearrangement could affect any rearranging multigene locus. Eventually such studies will lead to better designed clinical studies of the repertoire in disease, through the selection of control populations matched for environmental exposure and genetic background. In this respect, family studies will be most useful.

T-cell repertoires in healthy and diseased human tissues analysed by T-cell receptor beta-chain CDR3 size determination: evidence for oligoclonal expansions in tumours and inflammatory diseases

Many examples of oligoclonal T-cell expansion in infiltrated diseased tissues have been reported. However, it remains to be established whether such observations can be generalized and to what extent oligoclonal patterns obtained after in vitro culture of T-cell infiltrates reflect in vivo situations. Using new high resolution analysis which requires no in vitro cellular expansion, we detected such oligoclonal T-cell expansions in 7/7 melanoma tumour biopsies, 3/3 biopsies of inflammatory skin during acute graft versus host disease (aGVHD) after allogeneic bone marrow transplantation (alloBMT) and 7/7 synovial membranes from patients with rheumatoid arthritis. Thus, oligoclonal T-cell expansions are readily observed when a sufficiently sensitive detection method is used, suggesting that similar expansions are the rule among T-cell infiltrates in different diseases. This observation and the monitoring of the in vivo evolution of such expansion during the course of the disease and during in vitro culture should have important clinical implications.

V alpha gene usage in rheumatoid compared with osteoarthritic synovial tissue T cells

While many investigators have examined V gene usage by the clonotypic T-cell receptor (TCR) in rheumatoid arthritis (RA) joints, few have reported on arthritic controls. We compared TCR alpha-chain V gene usage in knee synovial tissue specimens from 9 RA and 5 osteoarthritis (OA) patients. There was no significant difference in the number of V gene families used in RA compared with OA synovium. However, there was an increased prevalence of V alpha 28, V alpha 10, V alpha 17, and V alpha 18 and under representation of V alpha 15 in RA compared with OA synovium. Of these, V alpha 28 was also recently described by us as being present in RA synovial tissue early in the course of disease. V alpha 28 associated J region usage, and N-regional diversity was surveyed in T-cell receptors from additional rheumatoid synovial tissue T-cell populations and normal peripheral blood. Oligoclonality was observed in 6/10 rheumatoid specimens either by direct sequencing or where three or more molecular clones were sequenced, compared with 0/5 normal PBMCs. The oligoclonal populations included 2/3 cell lines stimulated with interleukin-2 (IL-2) alone. Several novel J regions were observed, with some recurrent residues observed at N-region positions. These data indicate an increased prevalence of certain TCR V region families in RA versus OA synovium, and suggest an antigen-driven expansion of V alpha 28-expressing T cells in RA synovium.

Group A streptococcal antigens and superantigens in the pathogenesis of autoimmune arthritis

Evidence from repeated clinical observations and from a variety of experimental approaches implicates group A streptococci in the pathogenesis of the autoimmune arthritides. Several streptococcal antigens and superantigens have now been characterized and their properties suggest that they may be involved in the mechanisms which underlie these diseases, although other antigens and superantigens yet to be discovered may also be involved. The association between group A streptococcal infection and autoimmune arthritis offers a useful model for providing a long-elusive understanding of the role of bacterial infection in the pathogenesis of autoimmune disease.

Immunotherapeutic strategies targeting rheumatoid synovial T-cell receptors by DNA inoculation

Immunotherapy against autoreactive T-cell receptors (TCRs) has been reported to have promise in several animal models of autoimmune diseases. Facilitated DNA inoculation has many potential advantages as a modality for development of specific immune responses. Specifically, this technology is able to deliver exogenous antigens for processing via both the endogenous pathway, with subsequent presentation by class-I major histocompatibility (MHC) antigens, and the exogenous pathway, with subsequent presentation by class-II MHC antigens. This allows for induction of both arms of the cellular immune system. These cellular immune responses may be particularly important in targeting and controlling pathogenic cell populations. The application of this technology to the treatment of human autoimmune diseases depends on the availability of readily manipulated systems for the evaluation of specific interventions. Here we report the full length cloning and expression of TCRs from rheumatoid arthritis synovial tissue. These were developed by recombinant polymerase chain reaction, cloning and retroviral transduction into a TCR-alpha/beta-negative murine T-cell hybridoma. Reconstitution of CD3 expression was confirmed by flow cytometry. Similar constructs have been developed for TCR-based immunotherapy by facilitated inoculation of DNA intramuscularly. Preliminary analysis of immune responses in mice indicates that these constructs elicit anti-TCR responses. These studies indicate the ability to reconstitute expression of potentially autoreactive human TCRs in a model system wherein specific immune responses elicited against these TCRs by various immunogens can be evaluated.

T-cell antigen receptors in rheumatoid arthritis

Rheumatoid arthritis (RA) is a systemic disease of unknown etiology characterized by chronic inflammation mainly in the joints. Several lines of evidence suggest that T cells are involved in the pathogenesis of the disease. RA is associated with certain HLA-DR alleles. Studies analyzing T-cell receptor transcripts in RA have found biased or preferential usage of certain V alpha and/or V beta gene segments by T cells infiltrating the synovial membrane or extravasating into the synovial fluid compared to peripheral blood. In certain patients few T-cell antigen receptor (TCR) clones dominated the infiltrating T cells, suggesting that T cells from the synovial membrane or the synovial fluid comprise oligoclonal populations of T cells. However, other studies have found a polyclonal population of T cells. In interpreting these results the phase of the disease (early vs. late RA), the source of T cells and the limitations of the methods used in these studies should be taken into consideration. However, it appears that synovial T cells comprise oligoclonal populations of T cells and that there is a bias towards particular TCR gene segments, although a specific TCR gene segment in RA has not emerged.

T cell receptor analysis in rheumatoid arthritis: what have we learnt?

Many clues point to a role for T lymphocytes in the pathogenesis of rheumatoid arthritis (RA), although the importance of these cells and their position within the rheumatoid pathogenic scheme remain unknown. Encouraged by data from animal models of T-lymphocyte-mediated autoimmunity, a major focus of research into the role of T lymphocytes in RA has been the usage of T cell receptor V genes in rheumatoid synovitis. Despite many methodologic problems, involving choice of patients and controls, choice of specimens, and technical factors, several conclusions can be drawn from the published research. In particular, synovial T lymphocyte populations, as a whole, frequently show biased V gene usage and restricted clonality within those T lymphocyte subsets that utilize over-represented V gene families. Continued research into these synovial T lymphocyte subsets should provide important insights into the pathogenesis of RA, particularly if solutions to the identified methodologic problems are implemented.