Evidence for the effects of a superantigen in rheumatoid arthritis

Direct assessment of junctional diversity in rearranged T cell receptor beta chain encoding genes by combined heteroduplex and single strand conformation polymorphism (SSCP) analysis

In order to define the extent of T cell heterogeneity and clonality, unique DNA sequences in the junctional region in rearranged T cell receptor (TcR) genes can be studied. For this purpose we have adapted a non-denaturing nucleic acid gel electrophoresis procedure to detect TcR junctional diversity. Detection of junctional diversity is based upon electrophoretic separation of single stranded (ss) and double stranded (ds) DNA molecules via mobility shifts due to nucleotide sequence polymorphism. To examine the capacity of this nucleic acid gel electrophoresis procedure to detect nucleotide sequence polymorphism in the CDR 3 region within TcR V beta gene family sequences polymerase chain reaction (PCR) amplified TcR V beta 5.1/5.4 and V beta 14 cDNA sequences were analyzed. The results of this study showed that (1) the single strand conformation polymorphism (SSCP) procedure has a low capacity to discriminate between diverse TcR V beta cDNA sequences due to comigration of the ssDNA molecules, which results in an underestimation of the heterogeneity in a given T cell population; (2) comigrating ssDNA and/or dsDNA (homoduplex) molecules can be separated by the formation of heteroduplex molecules; these heteroduplex molecules provide essential additional information on the degree of nucleotide sequence polymorphism in the CDR 3 region within the TcR V beta cDNA sequences; (3) the double strand conformation polymorphism (DSCP) procedure provides a fast and reliable procedure to detect junctional diversity within the sequences tested. Using DSCP a more detailed assessment of amplified TcR V beta cDNA sequences can be obtained as compared with SSCP analysis only. Data obtained by gel analysis were very similar to those obtained by conventional bacterial cloning and DNA sequencing procedures on the corresponding cDNA clones. In conclusion, this new gel electrophoresis procedure allows a direct assessment of the extent of T cell heterogeneity and clonality by screening junctional diversity in TcR chain encoding sequences in clinical conditions with (oligo)clonal expansion of T lymphocytes.

A novel and efficient route for the isolation of antibodies that recognise T cell receptor V alpha(s)

Studies of the T cell repertoire have been hindered by the lack of antibodies that recognise V region families, particularly for V alpha regions. In this report, single chain Fv (scFv) fragments have been isolated that recognise both recombinant V alpha(s) and native V alpha(s) on the surface of T cells. Mice have been immunised with purified soluble T cell receptors (TCRs) and antibody heavy and light chain variable domain (VH and VL, respectively) genes isolated from splenocytes using the polymerase chain reaction (PCR). The VH and VL genes have been assembled as scFv gene libraries and a bacteriophage display system used to isolate scFvs that recognise a soluble V alpha. Five scFvs have been purified and characterised in detail using enzyme-linked immunosorbent assays (ELISAs) and flow cytometry. Three of these five scFvs recognise native V alpha(s) on the surface of T cell hybridomas. This method therefore offers a rapid route to the generation of scFvs that recognise native TCRs and can readily be extended to the production of anti-human TCR antibodies for use in therapy and diagnosis.

Changes in the peripheral blood T-Cell receptor V beta repertoire in vivo and in vitro during shigellosis

A sequential activation of T cells in peripheral blood during shigello sis has been observer (D. Islam, P.K. Bradham, A. A. Lindberg, and B. Christensson, Infect. Immun 63:2941-2949, 1995). To further investigate the cellular response during the course of Shigella infection, changes in the T-cell receptor (TCR) repertoire in the subsets in blood in patients during shigellosis was that Shigella antigens may modulate the function of T cells carrying TCRs capable of recognizing Shigella-specific epitopes or superantigens. Such a selective preference for T cells expressing certain TCR Vbeta types could lead to the expansion or deletion of these T cells. In the present study of 27 adult male Bangladeshi patients with dysentery (14 cases caused by Shigella Dysenteriae 1 and 13 cases caused by Shigella flexneri), the changes in the TCR Vbeta repertoire of peripheral blood CD4+ and CD8+ T-cell subsets have been analyzed with a panel of nine anti-Vbeta monoclonal antibodies by flow cytometry. Twenty healthy males from Bangladesh and 20 healthy males from Sweden served as controls. Compared with the Bangladeshi controls, the patients had an increased frequency of CD4+T cells expression Vbeta2, Vbeta3, and Vbeta17, with a maximum at day 7 after the onset of disease. The frequency of CD4+T cells expressing Vbeta5.1 was increased only in patients with S. flexneri infection. Peripheral blood T cells from Shigella-infected patients also responded to in vitro stimulation in a TCR Vbeta-specific manner. Stimulation with heat-killed S. dysenteriae 1 and Shiga toxin enhanced the frequency of cells expressing Vbeta2, Vbeta3, Vbeta5.1, Vbeta13.6, and Vbeta17, especially in samples obtained at day 7. The enhanced frequency of cells expressing Vbeta2, Vbeta3, Vbeta5.1, and Vbeta17 found both in in vivo and in vitro could suggest that in shigellosis antigens or superantigens are presented to the immune system and preferentially activate certain TCR Vbeta types in T-cell subsets. The kinetics of the change in the TCR Vbeta repertoire in blood during shigellosis may indicate that following local activation, the antigen activated T cells can be retrieved in the blood and restimulated in vitro. If confirmed by parallel analysis of T cells in the gut and blood by TCR sequence analysis, the possibility suggested by our findings would facilitate further analysis of the role of cell-mediated immune responses in the pathogenesis of and protection against Shigella infection.

Autoimmune mechanisms involved in the pathogenesis of rheumatoid arthritis

Rheumatoid arthritis (RA) was one of the first systemic disorders to be considered an autoimmune disease. Two major aspects of RA suggest a fundamental immune-mediated derangement in the disease: (1) presence of often massive lymphocytic infiltrates and activated CD4(+) T cells within the inflamed hypertrophied synovium, and (2) production of large amounts of rheumatoid factor (RF) by B-cells and plasma cells in the involved synovium itself. The actual tissue damage to joints and extra-articular structures affected by the disease comes from the rheumatoid inflammatory pannus or granulomatous collections of cells called rheumatoid nodules. RF production has long been studied as a prime example of apparent autoantibody production in association with the basic underlying disease process. RA patients who belong to subtype HLA DR4, Dw4 (DR B1 or 0401, Dw14 (0404/0408), or Dw15 (0405/0410) are most likely to be seropositive for RF and to have severe progressive disease. RFs are felt to represent an autoantibody associated with RA, since they show principal specificity for structures on the C gamma 3 and C gamma 2 (Fc) domains of IgG. Recent work by our group has defined a number of solvent-exposed linear RF-reactive epitopes on C gamma 3 and C gamma 2 using a strategy of overlapping 7-mers of primary sequence. RFs also have been demonstrated to react with two different regions, SKDWSFY and LSQPKIVKWDR, on beta 2-microglobulin (beta 2m). Many of the RF-reactive sites on C gamma 2 and C gamma 3 as well as on beta 2m show common immunodominant valines, leucines, tryptophanes, arginines, lysines, and glutamines, thus comprising common reactive residues. In the future, this approach may provide more direct insight into the specificities of other autoantibodies.

Evidence for involvement of superantigens in human periodontal diseases: skewed expression of T cell receptor variable regions by gingival T cells

Immunomodulation by periodontopathic bacteria has been implicated in the pathogenesis of inflammatory periodontal diseases. A novel class of microbial-derived T cell mitogens, referred to as superantigens, has recently been described. Superantigens are unique in that they induce a tremendous activation and expansion of specific subsets of T cells in an antigen-independent manner, thereby causing immune dysfunction. Subsets of superantigen-expanded T cells can be identified with reagents that discriminate among different families of the variable domains of the T cell antigen receptor beta-chain (V beta). Since superantigens expand one or a few of these T cell antigen receptor V beta families, T cell subsets that have been expanded by superantigens have restricted expression of one or a few V beta families. In the present study, we investigated the presence of putative superantigen-stimulated T cells in periodontitis sites, utilizing a panel monoclonal antibodies to T cell antigen receptor V beta families. Leukocytes were isolated from gingival tissues obtained from 8 periodontitis and 4 non-periodontitis patients by collagenase digestion. Three-color flow cytometric analysis of these gingival cells demonstrated that in most periodontitis patients examined, patterns of V beta expression among T cells are characteristic of superantigen stimulation, i.e., there is an elevation in the proportion of one or a few V beta families. Specifically, these analyses revealed that T cell subsets expressing V beta 5a and V beta 5b, V beta 6, V beta 8 and V beta 12 were each elevated greater than 2 standard deviations in at least one periodontitis patient compared with the mean of the non-periodontitis subjects. In some periodontitis patients, a less marked elevation of T cells that express V beta 3, V beta 5a, V beta 5b, V beta 6, V beta 8, V beta 12, and V beta 13 was noted (greater than 1 standard deviation higher than the mean of the V beta families in non-periodontics subjects). Interestingly, V beta 8+ T cells were elevated to some degree in all periodontitis patients examined. In contrast, T cells expressing V beta 2, V beta 17 and V beta 19 were not significantly different in any of the subjects studied. In most periodontitis but not non-periodontitis patients, up to 50% of all gingival T cells expressed one or a few T cell antigen receptor V beta families, suggesting that superantigens constitute a major pathway of T cell activation and expansion. Hence, our data support the hypothesis that a large proportion of T cells in periodontitis sites have been stimulated and expanded by superantigens, presumably produced by periodontitis-associated bacteria.

Identification of clonally expanded T cells in rheumatoid arthritis using a sequence enrichment nuclease assay

Identification of expanded clones engaged in immune and autoimmune responses is still imperfect, since they are often diluted by irrelevant cells expressing diverse specificities. To efficiently characterize T cell receptors expressed by clonally expanded lymphocytes in rheumatoid arthritis (RA) and other inflammatory conditions, we developed an assay system, termed sequence enrichment nuclease assay (SENA). Key elements of SENA are the efficiency of heat-denatured DNA strand reassociation, which increases exponentially with concentration, and the elimination of unhybridized sequences by single-strand-specific DNase. T cell clonal expansions were identified primarily in synovial fluids, but also in peripheral blood of RA patients. Synovial fluids had more prominent expansions in the CD8 than the CD4 subset, whereas clonal expansions in the CD4 subset predominated among peripheral blood lymphocytes. Dominant clones exhibited diverse sequences with no clear conservation of junctional motifs, although the same amino acid sequence was identified in two patients. In most instances, dominant clones in the blood were discordant to those in the corresponding synovial fluid, suggesting local stimulation or preferential sequestration of T cells displaying particular specifities.

Interleukin-10 functions as an antiinflammatory cytokine in rheumatoid synovium

OBJECTIVE

Interleukin-10 (IL-10) is an antiinflammatory cytokine that has been shown to play a role in rheumatoid arthritis (RA). We therefore investigated the effects of IL-10 on the function and phenotype of synovial fluid mononuclear cells (SFMC) derived from patients with RA. In addition, we studied the production of IL-10 in rheumatoid joints, and the role of endogenous IL-10 in the regulation of SFMC function.

METHODS

The presence of IL-10 in rheumatoid joints was studied using IL-10-specific enzyme-linked immunosorbent assay (ELISA) and reverse transcriptase- polymerase chain reaction (RT-PCR) techniques. The effects of recombinant human IL-10 or neutralizing anti-IL-10 monoclonal antibodies (MAbs) on both cytokine production and phenotype of SFMC were evaluated using cytokine-specific ELISAs and flow cytometry. The effect of IL-10 on proliferation of SFMC was determined by incorporation of tritiated thymidine.

RESULTS

IL-10 was detected by ELISA in 22 of 23 SF samples, and was spontaneously produced by cultured SFMC. IL-10 messenger RNA was detectable in all 8 SFMC samples, as determined by RT-PCR. Neutralization of endogenously produced IL-10 by anti- IL-10 MAbs resulted in increased production of IL-1 beta, tumor necrosis factor alpha (TNF alpha), and granulocyte- macrophage colony-stimulating factor (GM-CSF) by SFMC, and in enhanced proliferation of SFMC. In particular, the production of TNFalpha was dramatically increased by anti-IL-10 MAbs. Moreover, the expression of HLA-DR molecules by SF macrophages was increased, and the expression of CD16 was decreased by anti-IL-10 MAbs. In contrast, addition of recombinant IL-10 significantly decreased the production of IL-1 beta, TNF alpha, and GM-CSF by SFMC, and decreased spontaneous and IL-2-induced proliferation of SFMC. Finally, IL-10 decreased HLA-DR expression and increased the expression of the Fc gamma receptors, CD16 and CD64, by SF macrophages.

CONCLUSION

These data indicate that endogenously produced IL-10 functions as an immunoregulatory molecule in rheumatoid synovium. Importantly, exogenous IL-10 has potent antiinflammatory effects on SFMC, suggesting that IL-10 may be useful in the treatment of patients with RA.

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.

Reactivity of mouse T-cell hybridomas expressing human Vbeta gene segments with staphylococcal and streptococcal superantigens

A panel of 15 mouse T-cell hybridomas, each expressing a different human Vbeta gene segment (hVbeta) in an otherwise mouse T-cell receptor (i.e., mouse alpha chain and CD3 complex), was constructed by transfection of hVbeta/mouse Cbeta chimeric T-cell receptor (TCR)-beta genes into a mouse T-cell hybridoma recipient lacking the endogenous TCR-beta chain. Several qualities that are conferred by the hVbeta chain of the TCR are retained in the chimeric human-mouse TCR complex: a large panel of hVbeta-specific antibodies specifically stained the hVbeta expressed by the mouse T-cell hybridomas. Moreover, hVbeta-transfected mouse cells could readily produce interleukin 2 when stimulated by superantigens presented by antigen-presenting cells. These characteristics made it possible to refine the reactivity of 17 superantigen preparations with the available transfected Vbetas. Each superantigen gave a characteristic pattern of reactivity on the transfectants. Positive reactivities with some of these transfectants, which differ only by the expressed hVbeta, demonstrate unambiguously the superantigenic character of a protein or fraction and its potential to react with the corresponding Vbetas. Therefore, these hVbeta-transfected cells constituted a valuable tool for determining "specificity fingerprints" of known or putative superantigens. First, commonly used, commercially available superantigens such as staphylococcal enterotoxin B and toxic shock syndrome toxin-1 (TSST-1) showed additional Vbeta reactivities, compared with those of their recombinant counterparts. This stresses the importance of using defined preparations of superantigens for the definition of Vbeta specificities. Second, the stimulatory pattern of a strain of Streptococcus pyogenes demonstrated that this strain, unlike others, produces a potent Vbeta 8-specific superantigen that is an yet undefined at the molecular level.

Restricted usage of T-cell receptor V alpha genes in infiltrating cells in murine hearts with acute myocarditis caused by coxsackie virus B3

In murine myocarditis, it has been shown that natural killer cells first infiltrate the heart, followed by activated T-cells, which play an important role in the pathogenesis of the myocardial damage. In the same model of acute myocarditis, the repertoire of T-cell receptor (TCR) V beta genes in infiltrating cells in the heart has also been shown to be restricted. To study the nature of T-cell infiltration in more detail, the expression of TCR V alpha genes in infiltrating cells in the heart has been analysed by the polymerase chain reaction (PCR), confirmed by Southern blot hybridization with a C alpha cDNA probe. In contrast to spleen lymphocytes, the repertoire of V alpha gene transcripts in the heart was restricted. Infiltrating cells expressing V alpha 10 were found in five of eight hearts of mice with acute myocarditis and infiltrating cells expressing V alpha 7 and V alpha 3 were found in two of eight and one of eight hearts, respectively. Restricted TCR V alpha as well as V beta repertoires indicate that a specific antigen, in the heart was targeted, presented at the groove of major histocompatibility complex molecules. These findings raise the possibility of specific immunotherapy with synthetic TCR V alpha or V beta peptides to prevent T-cell-mediated myocardial damage in patients with viral myocarditis.

Biologic agents for the treatment of rheumatoid arthritis

Substantial progress has been made in our understanding of the immune system and immunopathogenesis of rheumatoid arthritis. This knowledge, combined with advances in biotechnology, has resulted in the development of biologic agents to selectively target elements of the immune system participating in the inflammatory response. This article reviews the available data from clinical trials of biologic agents for the treatment of rheumatoid arthritis. Randomized controlled trials comparing administration of a biologic agent to placebo are emphasized. Despite concerns raised by initial trials with these agents, they still offer the most promise as treatments for autoimmune diseases ++such as rheumatoid arthritis.

Heterogeneity of rearranged T cell receptor V alpha and V beta gene transcripts in synovial fluid T cells of HLA-B27 positive reactive arthritis patients

To analyze the T cell receptor (TCR) V-alpha/beta gene usage by synovial fluid (SF) and peripheral blood (PB) T cells of HLA-B27+ reactive arthritis (ReA) patients. The TCR V-alpha/beta gene usage was determined by the polymerase chain reaction on freshly isolated SF and PB mononuclear cells (MNC) of five HLA-B27+ ReA patients. A total of 30 TCR V alpha and 23 V beta (sub)family specific primers in combination with a C alpha or C beta specific primer, respectively, were used. In five patients most of the TCR V alpha and V beta gene segments expressed by PB T cells were also detected in the paired SF samples. Although one patient showed an increased expression of TCR V alpha2 in SF when compared to PB, the SF samples showed a heterogeneous TCR V-gene repertoire similar to PB. Although this study was limited to a small group of patients, the apparent lack of a restricted TCR V-gene repertoire in SF does not support the involvement of a single or limited number of T cell subsets in the disease process of HLA-B27+ ReA patients.

The T cell receptor (TCR) in HLA-B27-restricted T cell responses--an introduction

Recent data indicate that cytotoxic T lymphocytes (CTL) are involved in the pathogenesis of HLA-B27-associated spondylarthropathies. In the absence of clearly defined "arthritogenic" bacterial or self peptides that are presented by HLA-B27 and recognized by such CD8+CTL, one approach has been to investigate the T cell repertoire of lesional cellular infiltrates by determining T cell receptor (TCR) variable (V) gene segment frequencies. Furthermore, the TCR V alpha and V beta chains of HLA-B27-restricted CTL clones, notably the putative peptide-contacting CDR3-regions of these TCRs, have been sequenced. This article will give a short review of the current literature on the topology of the TCR and its hypervariable CDR3 region, TCR repertoire diversity in rheumatic diseases and will concentrate on TCR V alpha and V beta gene usage in HLA-B27-restricted T cell responses.

Biological significance of human endogenous retroviral sequences

Endogenous retroviruses (ERVs) have been known for many years to exist in numerous natural and laboratory animal species. In humans it has been demonstrated that at least 1% of the genome consists of retrovirus-related sequences. Involvement of ERVs in the development of neoplastic and autoimmune diseases in the mouse model implicated a potentially pathogenic role of ERVs for humans, too. The research in this field led to a number of results strongly suggesting that human endogenous retroviral sequences (HERVs) are biologically active, on the RNA and even on the protein level. Particle formation, regulation or dysregulation of cellular gene expression, and synthesis of potentially pathogenic viral proteins indicate the broad spectrum of mechanisms by which HERVs may obtain biological significance.

Non random usage of T cell receptor alpha gene expression in atopy using anchored PCR

The T cell receptor (TCR) alpha beta heterodimer recognises antigenic peptide fragments presented by Class II MHC. This interaction initiates T cell activation and cytokine release with subsequent recruitment of inflammatory cells. Previous work from our group suggests a qualitative difference in variable alpha gene expression in atopy as compared to non atopic controls. In this study we examine TCR alpha repertoire using anchored PCR to provide a quantitative assessment of the V alpha and J alpha repertoire. One atopic (DRB1*0701,DRB1*15: DRB4*0101, DRB5*01: DQB1* 0303, DQB1*601/2) and one non-atopic (DRB1*0701,DRB1*03011/2: DRB4*01, DRB3*0x: DQB1* 0303, DQB1*0201/2) control were studied. Variable gene usage was markedly limited in the atopic individual. V alpha 1, 3, 8 accounted for 60% and J alpha 12, 31 30% of the gene usage. There was evidence of preferential V alpha-J alpha gene pairing and clonal expansion. We conclude that there is a marked non random TCR alpha gene distribution in atopy using both V alpha family and anchored PCR. This may be due in part to antigen driven clonal expansion.

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.

The superantigen exfoliative toxin induces cutaneous lymphocyte-associated antigen expression in peripheral human T lymphocytes

Several immune-mediated dermatoses including psoriasis and atopic dermatitis can be exacerbated by bacterial infections. Superantigen producing bacteria can be isolated from skin lesions of these dermatoses. Consistent with superantigen effects, skewed T cell receptor variable gene usage has been demonstrated within these lesions. Therefore, the question arises whether superantigen induce a skin-seeking phenotype within peripheral T cells. In this study, we investigated the in vitro influence of the V beta 2-selective superantigen exfoliative toxin from Staphylococcus aureus on the expression of the cutaneous lymphocyte-associated antigen on peripheral T lymphocytes of healthy donors. We demonstrate that exfoliative toxin dramatically upregulates cutaneous lymphocyte-associated antigen expression on T cell receptor V beta 2+ lymphocytes. Up to 69% of V beta 2+ lymphocytes expressed cutaneous lymphocyte-associated antigen after 5 days of in vitro culture. Additionally, exfoliative toxin also increased cutaneous lymphocyte-associated antigen expression in CD3+ T cell receptor V beta 2- lymphocytes indicating a different effect as caused by the superantigen-T cell receptor V beta 2 interaction. Our findings suggest influence of bacterial superantigens on T lymphocyte skin homing in vivo.

Responsiveness of human T lymphocytes to bacterial superantigens presented by cultured rheumatoid arthritis synoviocytes

OBJECTIVE

Type B fibroblastic synoviocytes are abundant in inflamed joints of patients with rheumatoid arthritis (RA), and can secrete cytokines and other mediators of inflammation. The aim of this study was to determine whether cell lines derived from RA type B synoviocytes could also serve as accessory cells for T lymphocyte activation.

METHODS

Cells from RA synoviocyte lines, with or without preculture in interferon-gamma (IFN gamma), were cultured with purified peripheral blood T cells, in the presence or absence of superantigens or other accessory cell-dependent T cell mitogens. T cell proliferation was measured by thymidine incorporation, and synoviocyte surface markers were analyzed by flow cytometry.

RESULTS

RA type B synoviocyte lines were potent accessory cells for T cell responses to bacterial superantigens or lectins, and direct cell-cell contact was required. Preculture in IFN gamma augmented synoviocyte expression of major histocompatibility complex (MHC) class II molecules and of ligands for some T cell costimulatory receptors, but synoviocyte accessory cell function was evident even in the absence of IFN gamma. Blocking studies using monoclonal antibodies supported the notion of a role CD2, CD11a/CD18 and MHC class II molecules in synoviocyte-dependent T cell activation. Monoclonal antibodies against IFN gamma, interleukin-1 beta (IL-1 beta), IL-6, IL-8, and tumor necrosis factor alpha failed to block the T cell proliferative responses, but anti-IL-2 was strongly inhibitory.

CONCLUSION

Cultured RA and type B synoviocytes can perform some of the functions of professional antigen-presenting cells. If such cells have similar properties in vivo, they may be important participants in activation of immune responses, in addition to their previously described synthetic and proinflammatory roles. If RA synovial tissue T cells, like normal peripheral blood T cells, can respond to superantigens presented by synoviocytes, this interaction could be important in the pathogenesis of RA.

Definition of sites on HLA-DR1 involved in the T cell response to staphylococcal enterotoxins E and C2

We have exploited the relative inefficiency of interaction between staphylococcal enterotoxins, SEE or SEC2, and H-2Ek compared to HLA-DR1 molecules to deduce which regions of the major histocompatibility complex (MHC) class II molecule are involved in the T cell response to these superantigens. Transfectants expressing hybrid DR/H-2E MHC class II molecules were used to present SEE to the T cell receptor V beta 8.1-expressing Jurkat cell line, and SEC2 to human peripheral blood T cells. For SEE, the critical region of the class II molecule for T cell reactivity and for binding was the beta 1 domain alpha-helix. The functional data were corroborated by measurements of direct binding. Sequence comparison between DR and H-2E raised the possibility that the glutamic acid at position 84 in the beta chain of H-2Ek, in place of glycine was responsible for the observed functional effects. This suggestion was supported by the finding that DQw2 (glutamine at 84) transfectants supported the SEE response much more efficiently than DQw6 that has glutamic acid at this position. In addition, amino acid substitutions at either position 36 or 39 in the DR alpha 1 domain abolished T cell reactivity without any obvious alteration in binding. For SEC2, use of transfectants expressing exon-shuffled alpha and beta chain genes showed that replacement of the alpha 1, alpha 2 and beta 1 domains with H-2E sequence inhibited the presentation of SEC2. Similarly, the substitutions at positions 36 and 39 in the alpha 1 domain abolished the T cell response to SEC2. Taken together, these data may be best explained by a model in which these two toxins have primary binding sites on the beta 1 domain (SEE) and the alpha 1 and alpha 2 domains (SEC2), but by virtue of a secondary binding site on the opposite surface of the class II molecule, cross-link two adjacent DR molecules. Such cross-linking may be important in the induction of T cell reactivity.

Inflammatory neuropathies--pathogenesis and the role of intravenous immune globulin

The inflammatory neuropathies may be subdivided into an acute form, Guillain-Barré syndrome, and a chronic form referred to as chronic inflammatory demyelinating polyneuropathy. More recently a chronic, asymmetrical pure motor neuropathy with multifocal conduction blocks has been described. All three neuropathies are considered to be immune-mediated. Their response to therapy is discussed, with special emphasis on high-dose intravenous immune globulin. For Guillain-Barré syndrome the efficacy of intravenous immune globulin has been proven in a randomized clinical trial. In chronic inflammatory demyelinating polyneuropathy a response rate of over 60% in newly diagnosed patients is suggested. Clinical prognostic criteria, however, seem to be very important to predict the effect of intravenous immune globulin. In multifocal motor neuropathy intravenous immune globulin is at present the only alternative to cyclophosphamide.

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.

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.

Increased levels of serum IgM antibody to staphylococcal enterotoxin B in patients with rheumatoid arthritis

OBJECTIVE

To investigate the role of superantigen in rheumatoid arthritis (RA) by assaying the serum levels of staphylococcal enterotoxin B (SEB) antibodies.

METHODS

Serum IgG and IgM SEB antibodies were measured using an enzyme linked immunosorbent assay (ELISA), and confirmed by Western blot analysis. The T cell receptor V beta (TCR V beta) repertoire was analysed using the reverse transcriptase polymerase chain reaction.

RESULTS

RA patients had increased levels of serum IgM SEB antibody compared with normal subjects, patients with systemic lupus erythematosus, Sjögren's syndrome, and Behçet's disease. The titres of rheumatoid factor (RF) showed no correlation with the levels of IgM SEB antibodies, and the levels of SEB antibodies were not inhibited by the addition of human immunoglobulin, or after absorption of RF. RA patients whose disease duration was less than 10 years had greater levels of serum IgM SEB antibodies than those with disease duration more than 10 years. The levels of IgM and IgG SEB antibodies in synovial fluid from RA patients were correlated with those in their sera. Western blot analysis detected IgM and IgG SEB antibodies as a band of approximately 30 kDa molecular size. The percentage of TCR V beta 2, V beta 5.2, and V beta 12 in phytohaemagglutinin stimulated peripheral T cells correlated significantly with the levels of serum IgM SEB antibody in RA patients.

CONCLUSION

These results suggest that SEB, one of the superantigens, may have a critical role in the pathogenesis of RA.

In vivo effects of superantigens

Superantigens are potent immunostimulatory molecules that activate both T cells and antigen presenting cells. The consequences of superantigen exposure range from induction of T cell proliferation, massive cytokine release and systemic shock to immunosuppression and tolerance. Superantigens have been directly implicated in a number of human conditions including food poisoning and toxic shock. In addition, there is evidence to suggest that superantigens are involved in the initiation of autoimmunity, and the immune dysfunction associated with HIV infection. Because of their possible role in human disease, and their potential use in immune therapy, it is important that we more completely understand the in vivo effects of superantigens.

T cell receptor genetics, autoimmunity and asthma

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Characterization of human T-cell responses to Yersinia enterocolitica superantigen

We reported that antigenic preparations from Yersinia enterocolitica stimulate murine T cells in a manner consistent with that of superantigens. As a consequence we examined whether Y. enterocolitica antigenic preparations stimulate human T-cell cultures. Human T cells, enriched from peripheral blood lymphocytes, were stimulated to proliferate in the presence of Y. enterocolitica cytoplasmic and membrane preparations. This activity has also been shown to be sensitive to protease treatment, indicating the presence of a protein, and when separated by ion-exchange chromatography a single peak of activity is resolved. Furthermore, this proliferation was inhibited, in a dose-dependent manner, by the presence of antibodies directed against MHC class II antigens, indicating a requirement for these molecules. When these cells were stained with a panel of V beta-specific antibodies to determine if there was an enrichment of a particular V beta-bearing T-cell subset after stimulation, results indicate a significant enrichment of T cells bearing V beta 3, V beta 12, V beta 14, and V beta 17 over controls. Taken together, these data are consistent with a Y. enterocolitica product acting as a superantigen for human T cells.

Peripheral blood T lymphocytes in systemic vasculitis: increased T cell receptor V beta 2 gene usage in microscopic polyarteritis

Antigen recognition by T lymphocytes is mediated by cell surface receptors T cell specificity depends on the variable, diversity and junctional (VDJ) regions of the alpha and beta polypeptide chains of the T cell receptor (TCR). The expression of the variable region genes of the beta chain (V beta) has been analysed to study the involvement of peripheral blood T cells in systemic vasculitis. RNA was extracted from peripheral blood lymphocytes of 12 patients with microscopic polyarteritis, 10 with Wegener's granulomatosis, six with unclassified vasculitis, and 28 healthy age- and sex-matched individuals. Complementary DNA was made from RNA and amplified by the anchored polymerase chain reaction (PCR) using redundant oligonucleotide primers for the TCR V beta genes. To determine if the dominant usage of a V beta gene family reflected the presence of particular T cell clones, cDNA was amplified with primers for the specific V beta gene family. The product was screened for sequence homogeneity by single-stranded conformational polymorphism (SSCP) and cloned to sequence the adjoining TCR (D beta) J beta region. A significant increase in the mean percentage expression of the V beta 2.1 gene was seen in vasculitis patients (11.4 + 1.0% (mean + s.e.m.)) compared with controls (6.6 + 0.6%; P < 0.003). The most marked increase was seen in microscopic polyarteritis (13.9 + 1.7%; P < 0.0001). There were also increases in the expression of V beta 3, 13 and 14 in peripheral blood of vasculitis patients compared with controls. SSCP analysis of V beta 2.1 amplified products indicated the presence of oligoclonal bands in a smaller proportion of patients (8/27) than controls (12/28). There was no strong evidence for the conservation of the TCR V beta 2.1 junctional region sequence data from a sample group of three patients with oligoclonal bands. Thus, a subset of patients with systemic vasculitis, particularly those with microscopic polyarteritis, have increased TCR V beta 2.1 gene expression in their peripheral blood T cell repertoire. As superantigens binding V beta 2.1 are postulated to activate T cells with diverse CDR3 sequences, it is proposed that a superantigen is involved in the immunopathogenesis of vasculitis.

Restricted usage of T cell receptor V alpha-V beta genes in infiltrating cells in the hearts of patients with acute myocarditis and dilated cardiomyopathy

Prolonged myocardial cell damage initiated by acute myocarditis is thought to be one of the most important etiology of dilated cardiomyopathy. To investigate the immunological mechanisms involved in the pathogenesis of dilated cardiomyopathy, we analyzed the phenotypes of infiltrating cells and examined the expression of perforin in infiltrating cells in the hearts of patients with dilated cardiomyopathy as well as acute myocarditis. We also examined the expression of HLA and intercellular adhesion molecule-1 (ICAM-1) in myocardial tissue of these patients. Furthermore, to evaluate the antigen specificity of infiltrating T cells and persistence of viral genomes in the myocardial tissue, we analyzed the expression of T cell receptor (TCR) V alpha and V beta genes as well as enterovirus genomes by PCR. We found infiltration of perforin-expressing killer cells and enhanced expression of HLA class I and ICAM-1 in the myocardial tissue. We also found that the repertoires of TCR V alpha as well as V beta gene transcripts were restricted, indicating that a specific antigen in the hearts was targeted. Because no enterovirus genomes were detected in all patients, it is strongly suggested that a cell-mediated autoimmune mechanism triggered by virus infection may play a critical role in the pathogenesis of dilated cardiomyopathy. However, we could not exclude the possibility that viruses other than enteroviruses could be pathogenic in these patients.

Genetic background and environment contribute synergistically to the onset of autoimmune diseases

Autoimmune diseases result from the breakdown of "self" tolerance. Environmental factors appear to be responsible for triggering this errant immune response, directed against self-tissue determinants, only when a susceptible genetic background is present in an individual. Autoimmune diseases, normally characterized by their association with certain HLA alleles, also share other features: the presence of autoantibodies, autoreactive T lymphocytes, and an intermittent clinical course of exacerbations and remissions. In cases of organ-specific diseases, as well as in cases of multi-system autoimmune diseases, viruses are increasingly implicated as such environmental triggers. Current molecular biology techniques have permitted a fine dissection of the genetic background of susceptible individuals and have enabled a more complete characterization of the immunocompetent cells involved in this autoaggression. Molecular approaches will soon allow us to pinpoint the characteristics of the environmental stimuli, so that protective strategies could be formulated to spare susceptible individuals from their ill effects.

T cell receptor (TCR) V gene usage in patients with systemic necrotizing vasculitis

Wegener's granulomatosis (WG) and polyarteritis nodosa (PAN) are systemic necrotizing vasculitides of unknown etiology. These disorders run a fatal course if untreated. T lymphocytes are implicated in the pathogenesis of WG, since they have been found to infiltrate affected organs, and sIL-2R correlates with disease activity. To elucidate further the role of T cells in necrotizing vasculitis, we have used a panel of 12 TCR V-specific MoAbs to investigate the number of cells expressing certain V alpha and V beta gene segments in the CD4+ and CD8+ subsets of altogether 11 patients with WG or PAN. In the group of patients, we found abnormal expansions of T cells using particular TCR V alpha or V beta gene products. These T cell expansions were more numerous, of a dramatically higher magnitude, and frequently more often found in the CD4 subset, compared with T cell expansions identified in healthy individuals. In long-term studies of the T cell expansions for up to 18 months, a heterogeneous pattern was revealed, with no obvious correlation to clinical features such as disease activity or treatment. Studies of TCR V gene usage in this group of patients may help in understanding the pathogenesis of necrotizing vasculitis, and in the identification of unknown antigens, and may open the possibility to a highly selective immunotherapy by targeting disease-mediating T cells.

T cell receptor usage in autoimmune disease

Activated T-cells are believed to play a critical role in the pathogenesis of autoimmune disease. In experimental allergic encephalomyelitis (EAE), an animal model resembling human multiple sclerosis (MS), there is evidence that T cells reactive to myelin basic protein mediate an inflammatory response within the central nervous system leading to demyelination. Furthermore, encephalitogenic T cells express TCR with highly restricted V gene usage and consequently specific forms of immunotherapy directed against V gene products have been successful in preventing and treating EAE. These findings prompted studies into the analysis of TCR repertoire expression in human autoimmune diseases in an attempt to identify the TCR usage of autoreactive and potentially pathogenic T cells. However, this has proved difficult as the autoantigens that drive the T cell response in most human autoimmune disorders are unknown. This review examines the data that have accumulated over the past few years on TCR usage in human autoimmune diseases and is focused largely on rheumatoid arthritis and MS.

Activation and clonal expansion of human myelin basic protein-reactive T cells by bacterial superantigens

Autoreactive T cells specific for myelin basic protein (MBP) are part of the normal T cell repertoire and are present both in patients with multiple sclerosis (MS) and healthy individuals. There is evidence suggesting in vivo activation and persistent clonal expansion of MBP-reactive T cells in MS. This study was undertaken to investigate the potential role of bacterial superantigens (SA) in the activation of MBP-reactive T cells. Twenty-seven MBP-reactive T cell clones generated from 10 MS patients and one normal individual were examined for reactivity to SA, in association with their T cell receptor V beta gene usage. The majority of the clones responded to at least one of the SA tested, staphylococcal enterotoxins (SEA and SEB) and toxic shock syndrome toxin-1 (TSST-1). The clones reactive to SEA and SEB expressed various V beta genes while T cell reactivity to TSST-1 correlated with the V beta 2 expression. Furthermore, circulating MBP-reactive T cells could be expanded from lymphocyte cultures primarily exposed to respective SA in more than 50% of MS patients and normal individuals tested. However, activation and expansion of circulating MBP-reactive T cells by SA was not directly associated with the disease. This study lends support to the potential role of SA in the activation of MBP-reactive T cells and suggests that an altered regulatory mechanism may account for further expansion and persistence of MBP-reactive T cells in MS.

Unique T-cell receptor junctional sequences found in multiple sclerosis and T-cells mediating experimental allergic encephalomyelitis

We have used two approaches to isolate TCR sequences that are unique to patients with multiple sclerosis. One strategy was to sequence TCR gene rearrangements directly from MS lesions. The second strategy utilized T-cell clones with a selectable mutation that are found only in MS patients. The selection of T-cell clones with mutations in the hypoxanthine guanine phosphoribosyltransferase (hprt) gene was used to isolate T-cells reactive to myelin basic protein (MBP) in patients with multiple sclerosis (MS). These T-cell clones are activated in vivo, and are not found in healthy individuals. The third complementarity determining regions (CDR3) of the T-cell receptor (TCR) alpha and beta chains are the putative contact sites for peptide fragments of MBP bound in the groove of the HLA molecule. The TCR V gene usage and CDR3s of these MBP-reactive hprt- T-cell clones are homologous to TCRs from other T-cells relevant to MS, including T-cells causing experimental allergic encephalomyelitis (EAE) and T-cells found in brain lesions and in the cerebrospinal fluid (CSF) of MS patients. In vivo activated MBP-reactive T-cells in MS patients may be critical in the pathogenesis of MS.

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.

CD8+ T-cells in psoriatic lesions preferentially use T-cell receptors V beta 3 and/or V beta 13.1 genes

Restricted T-cell receptor V beta gene use in animal models of autoimmune disease has led to the development of strategies to treat autoimmune disease by targeting the T-cell receptors of the pathogenic T-cells. Restricted T-cell receptor gene use has been noted in human autoimmune diseases such as rheumatoid arthritis and multiple sclerosis. We report here the finding of restricted T-cell receptor gene use in psoriasis vulgaris, as well. Our results show an elevated skin (over PBL) expression of V beta 3 and/or V beta 13.1 messages in the CD8+ T-cells in a majority of patients studied. CDR3 sequence analysis on these two V beta s from the skin demonstrated monoclonality or marked oligoclonality. A second biopsy performed 3.5 to 8 months later in four patients, at the same or different lesions, again revealed an elevated V beta 3 and/or V beta 13.1 expression and clonality. Moreover, in three of the four patients, the same TcR V beta CDR3 rearrangement was found in both biopsies, although there was no V beta CDR3 homology noted between patients. In two patients in which V beta 3 and/or V beta 13.1 was not elevated in the CD8+ T-cell population, an increase in V beta 17 gene use and clonality was found. The persistence of V beta 3- and/or V beta 13.1-bearing CD8+ T-cells in lesions that did not undergo resolution suggests their role as effector cells rather than as regulatory cells. The effector function of these CD8+ T-cells is further supported by the clonality of TcR V beta sequence data, which indicates they are recruited and expanded in situ. The V beta s identified in this study are candidate targets for selective immunotherapeutic intervention in psoriasis.