Evidence for the effects of a superantigen in rheumatoid arthritis

T lymphocytes in giant cell arteritic lesions are polyclonal cells expressing alpha beta type antigen receptors and VLA-1 integrin receptors

Giant cell arteritis (GCA) is a common disease in the elderly. It is characterized by focal inflammatory lesions dominated by T lymphocytes and macrophages. The etiology of GCA is, however, still unknown. The aim of the present study was to determine whether lesional T cells represent clonal proliferations, and to characterize adhesion receptors that could be important for recruitment of T cells and antigen receptors involved in their activation. Temporal artery biopsies were obtained from 13 patients presenting with clinical signs of GCA. Immunohistochemistry was used to characterize cell surface receptors on CD3+ T cells in situ in the lesions of eight patients with biopsy-verified GCA. The overwhelming majority of T cells in GCA lesions expressed the TCR alpha beta receptors. In sections from three of eight patients, a small proportion of cells expressing TCR gamma delta was also seen. Almost all T cells expressed the integrin receptors, LFA-1 and VLA-1, as determined by double-staining. To characterize the clonal composition of the lesional T cell population, cells were isolated by collagenase digestion of two lesions and T cells cloned by limiting dilution in the presence of mitogenic antibodies, IL-2 and autologous feeder cells. Rearrangements of the T cell receptor (TCR) genes of the clones were analysed by Southern hybridization using probes for TCR gamma and beta genes. T cell clones established from GCA lesions exhibited heterogeneous rearrangement patterns, indicating a polyclonal origin of the cells. We conclude that GCA lesions contain T lymphocytes that are of polyclonal origin and express integrin-type adhesion receptors. This supports the hypothesis that GCA involves an inflammatory response during which polyclonal T cells adhere to arterial tissue components and accumulate in the developing lesions.

Characterization of T cell repertoire changes in acute Kawasaki disease

Kawasaki disease (KD) is an acute multisystem vasculitis of unknown etiology that is associated with marked activation of T cells and monocyte/macrophages. Using a quantitative polymerase chain reaction (PCR) technique, we recently found that the acute phase of KD is associated with the expansion of T cells expressing the V beta 2 and V beta 8.1 gene segments. In the present work, we used a newly developed anti-V beta 2 monoclonal antibody (mAb) and studied a new group of KD patients to extend our previous PCR results. Immunofluorescence analysis confirmed that V beta 2-bearing T cells are selectively increased in patients with acute KD. The increase occurred primarily in the CD4 T cell subset. The percentages of V beta 2+ T cells as determined by mAb reactivity and flow cytometry correlated linearly with V beta expression as quantitated by PCR. However, T cells from acute KD patients appeared to express proportionately higher levels of V beta 2 transcripts per cell as compared with healthy controls or convalescent KD patients. Sequence analysis of T cell receptor beta chain genes of V beta 2 and V beta 8.1 expressing T cells from acute KD patients showed extensive junctional region diversity. These data showing polyclonal expansion of V beta 2+ and V beta 8+ T cells in acute KD provide additional insight into the immunopathogenesis of this disease.

Lack of preferential V beta usage in synovial T cells of rheumatoid arthritis patients

The T-cell receptor V beta subfamily repertoires of synovial and peripheral T cells of 8 rheumatoid arthritis (RA) patients were determined using the polymerase chain reaction. Three normal controls were included. Some of the rheumatoid synovial samples did not express the complete range of V beta families and lacked as many as 6 gene families. However, these patients showed considerable individual variation in expression. Overall, the data do not support preferential T-cell receptor V beta usage in synovial T cells of RA patients either in comparison to their autochthonous peripheral T cells or to peripheral T cells of normal subjects.

Bacterial and viral superantigens: roles in autoimmunity?

Superantigens are bacterial, viral, or retroviral proteins which can activate specifically a large proportion of T cells. In contrast with classical peptide antigen recognition, superantigens do not require processing to small peptides but act as complete or partially processed proteins. They can bind to major histocompatibility complex class II molecules and stimulate T cells expressing particular T cell receptor V beta chains. The other polymorphic parts of the T cell receptor, which are crucial for classical antigen recognition, are not important for this interaction. When this strategy is used a large proportion of the host immune system can be activated shortly after infection. The activated cells have a wide variety of antigen specificities. The ability to stimulate polyclonal B (IgG) as well as T cell responses raises possibilities of a role for superantigens in the induction of autoimmune diseases. Superantigens have been a great tool in the hands of immunologists in unravelling some of the basic mechanisms of tolerance and immunity.

T-cell receptor beta-chain binding to enterotoxin superantigens

The last few years have seen an enormous jump in our knowledge and understanding of T-cell activation by superantigens. Clearly, a great number of infectious and parasitic organisms utilize superantigens as part of a strategy to evade the immune response of their host. The ability to modulate superantigen effects will give us new means to fight infections, and the knowledge of T-cell activation that we have gained from study of superantigens will, in turn, allow us to modulate the immune system in new ways.

Intravenous immunoglobulin contains specific antibodies inhibitory to activation of T cells by staphylococcal toxin superantigens [see comment]

Superantigens are products of bacteria with dual affinity for HLA-DR and the variable region of the beta chain of the T cell receptor, leading to the stimulation of large numbers of T cells. Because there is evidence for the involvement of superantigens in various disease conditions in which intravenous IgG (IVIgG) is used as therapy, the purpose of the present study was to determine if IVIgG contains antibodies inhibitory to T cell stimulation by the superantigens. ELISA and Western assays revealed high concentrations of antibodies in the pooled IgG against eight different staphylococcal toxin (Staph-toxin) superantigens. The IVIgG inhibited in vitro stimulation of human peripheral blood T cells by the Staph-toxins, but did not inhibit responses elicited by phytohemagglutinin or anti-CD3. Inhibition was mediated by Staph-toxin-specific antibodies as shown by affinity adsorption depletion studies. The antibodies functioned by inhibiting the binding and/or presentation of Staph-toxins by DR+ accessory cells. In conclusion, this report is the first to show that normal pooled IgG contains antibodies against a major group of the superantigens, the Staph-toxins, and that the antibodies can inhibit Staph-toxin-elicited T cell activation, suggesting a possible immunoregulatory role for the antibodies in vivo.

Oligoclonal T cells in rheumatoid arthritis: identification strategy and molecular characterization of a clonal T-cell receptor

Immunodominant antigens in rheumatoid arthritis (RA) should induce an expansion of T cells bearing a corresponding T-cell receptor (TCR). We therefore analysed the TCR repertoire at the site of inflammation using two fundamentally different strategies. The total TCR repertoire was examined by generating 'representative' T-cell clone panels, which were subsequently tested for clonality by restriction mapping of the TCR beta gene locus. No clonality was detected in large T-cell clone panels generated with cells from three patients. However, when we selectively analysed the TCR repertoire of in vivo pre-activated, interleukin-2 (IL-2)-responsive T cells, significant T-cell/TCR clonality was found in 2 out of 4 patients. The clonal T cells represented a minority of the total T-cell population with an estimated frequency of 1 in 300 to 1 in 1000 cells. Molecular characterization of a clonal TCR and the use of a specific TCR V beta MoAb ruled out an over-representation of T cells bearing the same V beta element in the total T-cell population, rendering the involvement of super-antigens in the induction of T-cell clonality in this case unlikely.

Suppression of murine collagen-induced arthritis by treatment with a novel thiazole derivative, SM-8849

The antiarthritic activity of a novel thiazole derivative, SM-8849, was compared with that of indomethacin and D-penicillamine, in mice with collagen-induced arthritis. SM-8849 reduced the incidence and severity of disease in collagen-immunized mice, as assessed by clinical observation. This efficacy was also confirmed by radiographic and histologic studies. Indomethacin produced an apparent reduction of the clinical score, but had only a marginal effect on bone destruction. D-penicillamine did not produce any improvement. Unlike indomethacin and D-penicillamine, SM-8849 reduced the serum levels of anti-type II collagen antibodies. Flow cytometric analysis of spleen cells from arthritic mice revealed an increase in T cells expressing activation antigens (class II antigens) in comparison with normal mice. Treatment with SM-8849, but not indomethacin or D-penicillamine, prevented the increase in Ia-bearing T cells. The results suggest that an effect of SM-8849 on immunocompetent cells may be responsible for the antiarthritic activity of the compound, and this would distinguish its action from that of traditional antirheumatic drugs.

Selection of T lymphocytes bearing limited T-cell receptor beta chains in the response to a human pathogen

Delayed-type hypersensitivity (DTH) is a classic measure of T-cell responsiveness to foreign antigen. To estimate the extent of the T-cell repertoire in the DTH response to a human pathogen, we measured T-cell receptor (TCR) beta-chain variable-region (V beta) gene usage in reversal reactions in leprosy. Reversal reactions represent naturally occurring DTH responses in leprosy, in which augmentation of T-cell responses to Mycobacterium leprae is concomitant with clearance of bacilli from lesions. T cells using the V beta 6-, V beta 12-, V beta 14-, and V beta 19-encoded TCRs were strikingly overrepresented in the lesions of patients as compared to blood and pre-DTH lesions from the same individuals. Furthermore, these data indicate a possible association between the predominant expression of a V beta gene segment in lesions and the major histocompatibility complex class II haplotype of the individual. V beta 6 was prominent in the lesions of four patients who were DR15, a marker of resistance in leprosy infection. Sequence analysis of V beta 6 TCRs showed frequent use of V beta 6.1 and J beta 2.7 gene segments and a conserved amino acid motif in the V-J junction in a reversal-reaction lesion, but not in blood from the same patient. The limited TCR repertoire expressed by the infiltrating T cells suggests that a limited set of antigens is recognized in the DTH response to a human pathogen. We suggest that the mechanism by which major histocompatibility complex haplotype influences DTH in this disease involves the presentation of specific peptides, with subsequent selection of specific TCRs followed by local oligoclonal expansion.

Human B cell differentiation induced by microbial superantigens: unselected peripheral blood lymphocytes secrete polyclonal immunoglobulin in response to Mycoplasma arthritidis mitogen

Microbial superantigens (SA) activate a significant portion of the T cell repertoire based on their dual avidity for MHC class II antigens and T cell receptor (TCR) epitopes common to products of one or several TCR beta chain variable gene families. While SA that induce massive T cell proliferation and cytokine secretion have been implicated in clinical syndromes characterized by shock and generalized immunosuppression, SA activation of a more restricted T cell response may also have significant, perhaps immunostimulatory, effects on the immune system. To investigate this issue, we measured 3H-thymidine incorporation and polyclonal IgM and IgG secretion by normal human peripheral blood mononuclear cells (PBMC) cultured with a panel of microbial SA, including the Staphylococcus aureus-derived SA, SEA, SEB, SEC-1, SEC-2, SEC-3, SEE, TSST-1, and the Mycoplasma arthritidis-derived SA, MAM. The S. aureus-derived SA induce vigorous proliferation by PBMC, while optimal MAM-induced proliferation is significantly lower in magnitude. In all 12 subjects tested, mitogenic concentrations of MAM reproducibly stimulate unselected PBMC to secrete polyclonal IgM and IgG. In contrast, the S. aureus-derived SA induce Ig production only in cultures containing isolated B cell populations and either very low numbers of untreated autologous T cells, larger numbers of X-irradiated autologous T cells, or very low concentrations of the SA. No difference in the activation of helper (CD4) versus suppressor/cytotoxic (CD8) T cells by MAM and the S. aureus-derived SA was noted. Taken together, these data suggest that MAM's capacity to induce B cell differentiation correlates with its induction of a relatively weak proliferative response by unselected human T cells. MAM-like SA, when encountered in vivo, may result in a significant perturbation of the human immune system and potentially contribute to clinical syndromes characterized by immunostimulation and hypergammaglobulinemia.

Dissociation of autoaggression and self-superantigen reactivity

Self-superantigens have been described as products of endogenous retroviruses of the mouse ('minor lymphocyte stimulating loci') that are capable of interacting without prior processing with conserved domains of TCR V beta chains, causing the activation and deletion of most T cells expressing products of determined V beta gene families [1-4]. The fact that superantigens activate a far higher percentage of T cells (1-20%) than conventional, peptidic antigens (< 0.1%) provides the methodological advantage that the degree of clonal deletion may be measured by the analysis of the TCR repertoire using appropriate anti-V beta antibodies. Although much information on the spatio-temporal organization of repertoire-purging has been gathered by virtue of self-superantigens, serious doubts exist as to the possibility that such structures serve as pathogenetically relevant autoantigens. Thus, certain inbred mice spontaneously develop autoimmune diseases, although they bear T-cell repertoires that appear to be purged from self-superantigen-reactive V beta products. In addition, therapeutic interventions targeted to V beta gene products that are not specific for self-superantigens are successful in preventing disease development. The lack of correlation between superantigen-related V beta deletions and autoimmune disease development is substantiated in further models of murine autoimmunity. Based on these observations, we formulate the hypothesis that self-superantigen-reactive T cells are not involved in the development of autoimmune diseases.

T-cell receptors and collagen induced arthritis in H-2r mice

Mouse strains B10, B10.RIII, RIIIS/J and the F1 and backcross progeny arising from them were tested for susceptibility to porcine type II collagen-induced arthritis (PII-CIA). The clinically severe arthritis of rapid onset that is characteristic of PII-immunized B10.RIII mice developed predominantly in hybrid offspring that had inherited at least one copy of wild type T cell receptor (TCR) genes (V beta b genotype) from the B10 or B10.RIII parent. The results indicate that, in the development of PII-CIA, mice expressing the H-2r/r haplotype preferentially utilize TCR V beta genes that are normally encoded within the TCR V beta genomic deletion region of RIIIS mice (V beta c). After aggressive immunization with PII, the use of alternative TCR V beta genes, encoded outside of the RIIIS deletion region, produced a high IgG antibody response that was cross-reactive with mouse type II collagen (MII) and equivalent to that of B10.RIII mice, but only a very mild, late onset arthritis of 56% (27/48) incidence in RIIIS male mice and 28% (10/35) incidence in RIIIS female mice. In comparison, B10.RIII mice routinely developed early onset of PII-CIA of significantly higher incidence (100%; p < 0.005) and four-fold greater severity, even after milder immunization protocols. The data are compatible with the proposal that the clinically weak CIA response of RIIIs mice may be primarily antibody driven while the severe CIA of B10.RIII mice reflects the added inflammatory effects of collagen-reactive effector-T cells in the joint.(ABSTRACT TRUNCATED AT 250 WORDS)

Clonal expansion of lung V delta 1+ T cells in pulmonary sarcoidosis

Sarcoidosis is a multisystem disease of unknown etiology characterized by the presence of noncaseating granulomas in involved tissues. To investigate a potential role for gamma/delta T cells in the pathogenesis of pulmonary sarcoidosis, we studied lung and blood T cells from patients for preferential expression of particular gamma/delta T cell receptors. An abnormally high percentage of gamma/delta cells was found in the blood of some patients. However, the increased percentage did not reflect an increase in absolute number, and appeared to be secondary to a decrease in T cells expressing alpha/beta receptors. Furthermore, as in normals, the circulating gamma/delta cells in patients predominantly expressed V gamma 9/V delta 2 receptors, a subset that was not enriched at the site of disease. In contrast, in the lung, an increased percentage of gamma/delta cells expressing V delta 1 was found in a subset of patients. Importantly, these cells demonstrated evidence of prior activation by selectively expanding in vitro in the presence of interleukin 2. Furthermore, an analysis of junctional region sequences revealed their clonal nature. These clonal expansions of V delta 1+ cells in pulmonary sarcoidosis provide evidence for a disease process that involves specific recognition of a local antigen by T cells, and contributes new information regarding the nature of the as yet undefined antigenic stimulus.

Effects of different culture protocols on the expression of discrete T-cell receptor variable regions in human tumour infiltrating lymphocytes

Therapeutic effects of tumour infiltrating lymphocytes (TIL) rely on T-cell receptor (TCR) engagement. In this work, the expression of five TCR alpha/beta variable (V) domains was quantitatively analysed by means of a panel of monoclonal antibodies (Mab) recognising gene products from TCR V alpha 2, V beta 5, V beta 6, V beta 8 and V beta 12 families in freshly isolated TIL and in autologous peripheral blood mononuclear cells (PBMC) from patients with neoplasms. In 3 out of 6 cases, differences in the expression of V beta 5, V beta 6, V beta 8 or V beta 12 could be detected. TIL populations were expanded by using recombinant human interleukin-2 (rhIL-2) alone or in addition to solid phase bound anti-CD3 Mab. Cultured TIL showed similar CD4/CD8 ratios and cytotoxic activity against autologous neoplastic target cells, regardless of the activation protocol. In 4 patients, the expression of TCR alpha/beta V gene products, as compared with TIL from freshly excised tumours, was found to be modified in cultured TIL, especially in cell populations activated with rhIL-2 only. These results indicate that TCR V gene usage in TIL may quantitatively differ from that in PBMC. TIL culture protocols using rhIL-2 alone or in combination with solid phase bound anti-CD3 may result in differential expression of discrete TCR V families.

Superantigens and their potential role in human disease

In the past few years, there has been a virtual explosion of information on the viral and bacterial molecules now known as superantigens. Some structures have been defined and the mechanism by which they interact with MHC class II and the V beta region of the T cell receptor is being clarified. Data are accumulating regarding the importance of virally encoded superantigens in infectivity, viral replication, and the life cycle of the virus. In the case of MMTV, evidence also suggests that superantigens encoded by a provirus may be maintained by the host to protect against future exogenous MMTV infection. Experiments in animals have also begun to elucidate the dramatic and variable effects of superantigens on responding T cells and other immune processes. Finally, the role of superantigens in certain human diseases such as toxic shock syndrome, some autoimmune diseases like Kawasaki syndrome, and perhaps some immunodeficiency disease such as that secondary to HIV infection is being addressed and mechanisms are being defined. Still, numerous important questions remain. For example, it is not clear how superantigens with such different structures, for example, SEB, TSST-1, and MMTV vSAG, can interact with MHC and a similar region of the TCR in such basically similar ways. It remains to be determined whether there are human equivalents of the endogenous murine MMTV superantigens. The functional role of bacterial superantigens also remains to be explained. Serious infection and serious consequences from toxin-producing bacteria are relatively rare events, and it is questionable whether such events are involved in the selection pressure to maintain production of a functional superantigen. Hypotheses to explain these molecules, which can differ greatly in structure, include T cell stimulation-mediated suppression of host responses or enhancement of environments for bacterial growth and replication, but substantiating data for these ideas are mostly absent. It also seems likely that only the tip of the iceberg has been uncovered in terms of the role of superantigens in human disease. Unlike toxic shock syndrome, other associations, especially with viral superantigens, may be quite subtle and defined only after considerable effort. The definition of these molecules and mechanisms of disease may result in new therapeutic strategies. Finally, it is apparent that superantigens have dramatic effects on the immune system. One wonders whether these molecules or modifications of them can be used as specific modulators of the immune system to treat disease.

An altered repertoire of T cell receptor V gene expression by rheumatoid synovial fluid T lymphocytes

The pattern of T cell receptor V gene expression by lymphocytes from rheumatoid synovial fluid and paired peripheral blood samples was compared using a polymerase chain reaction (PCR)-based assay. Eight rheumatoid arthritis (RA) patients who had varying durations of disease (from 2 to 20 years) were studied. In all patients there was evidence of a different pattern of V gene expression between the two compartments. Significantly increased expression of at least one V alpha or V beta gene family by synovial fluid T cells was observed in all the patients studied. Three different V alpha (V alpha 10, 15 and 18) and three V beta (V beta 4, 5 and 13) families were commonly elevated. Sequencing of synovial V beta transcripts demonstrated that the basis of increased expression of selected V gene families in the synovial fluid was due to the presence of dominant clonotypes within those families, which constituted up to 53% of the sequences isolated from one particular synovial V gene family. There were considerable differences in the NDJ sequences found in synovial and peripheral blood T cell receptor (TCR) transcripts of the same V beta gene family. These data suggest that the TCR repertoire in the two compartments differs, and that antigen-driven expansion of particular synovial T cell populations is a component of rheumatoid synovitis, and is present in all stages of the disease.

Rheumatoid arthritis

Rheumatoid arthritis is often considered to be an autoimmune disease in which the abnormal immunological response is triggered by an infectious agent(s) but progress towards identifying such extrinsic factors has so far been unrevealing. In contrast, the genetic component of host susceptibility is slowly becoming clearer. In particular, the nature of the HLA class II association with the disease has led to new insights into its pathogenesis and possible novel forms of therapy.

Generation of monoclonal antibodies against a human T cell receptor beta chain expressed in transgenic mice

The generation of a panel of monoclonal antibodies specific for different variable (V) regions of human T cell receptors will be of great importance in the study of T cell-mediated diseases. However, relatively few such reagents exist, due in part to the poor immunogenicity of TcRs on the surface of human T cells. We have employed a strategy in which T cells from a transgenic mouse line expressing a human V beta 3 C beta 1 TcR were used to immunise syngeneic conventional mice to generate two monoclonal antibodies specific for human T cell receptors. Binding of antibody JOVI.3, which stained approximately 5% of human peripheral blood CD3 positive T cells, correlated with the expression of the human TcR V beta 3 gene segment. Antibody JOVI.1 recognised a determinant on the majority of TcRs, staining 50-75% of peripheral blood T cells and T cell lines expressing different V beta regions. Some TcRs, however, failed to react with this antibody. Both antibodies immunoprecipitated detergent-solubilised TcR molecules and were capable of inducing proliferation of peripheral blood T cells.

The interplay of microbes and their hosts

Microbes and their hosts exert considerable evolutionary pressure on one another. This brief report of a recent meeting describes the strategies and tactics, and highlights some of the key molecules involved in the complex host-parasite relationship.

Restricted junctional usage of T cell receptor V beta 2 and V beta 13 genes, which are overrepresented on infiltrating T cells in the lips of patients with Sjögren's syndrome

OBJECTIVE

To analyze the clonality of T cell receptor (TCR) V beta 2- and V beta 13-positive T cells, which are predominantly expressed in the lips of patients with Sjögren's syndrome (SS).

METHODS

The junctional sequences of complementary DNA clones encoding TCR V beta 2 and V beta 13 genes were determined by the polymerase chain reaction. Forty-one V beta 2 and 45 V beta 13 clones established from the lips of 3 SS patients were sequenced.

RESULTS

The V beta 2/J beta 2.3 pair was enriched in 2 of the 3 patients (44% and 46% of the clones, respectively), and the V beta 13/J beta 2.1 sequence was dominant in 2 of the 3 (23% and 45%). These pairs were not used preferentially in peripheral blood lymphocytes from the same patients.

CONCLUSION

Infiltrating V beta 2- and V beta 13-positive T cells from the lips of all 3 patients with SS were polyclonal, but the junctional usage of cells from 2 lip samples was restricted, compared with cells from peripheral blood. This suggests that not all expanded cells from the lips of SS patients are stimulated by superantigens.

CD28 and staphylococcal enterotoxins synergize to induce MHC-independent T-cell proliferation

The bacterial exotoxins staphylococcal enterotoxin A and B (SEA and SEB) mediate disease through their effects on T lymphocytes. In this manuscript we have demonstrated that both SEA and SEB can directly activate purified T cells in the absence of accessory cells as determined by a transition from G0 to G1 and induction of IL-2 receptor expression. However, neither SEA nor SEB alone was sufficient to result in T-cell proliferation. The induction of T-cell proliferation by SEB or SEA required the addition of a second costimulatory signal. This could be provided by either accessory cells or monoclonal antibody stimulation of CD28. As previously reported, T-cell proliferation induced by enterotoxin in the presence of accessory cells was partially inhibited by a blocking antibody against class II MHC. In contrast, in purified T cells when costimulation was provided through CD28, proliferation was not inhibited by class II antibody, and HLA-DR expression was not detectable. In addition, costimulation through CD28 was partially resistant to the effects of cyclosporin A. These results demonstrate that CD28 costimulation is sufficient to induce proliferation of enterotoxin-activated T cells, and that this effect is independent of class II MHC expression.

Limited T-cell receptor beta-chain diversity of a T-helper cell type 1-like response to Mycobacterium leprae

Delayed-type hypersensitivity (DTH) is the standard measure of T-cell responsiveness to infectious organisms. For leprosy, the Mitsuda reaction, a local immune response to cutaneous challenge with Mycobacterium leprae, is considered to represent a measure of DTH against the pathogen. We analyzed the diversity of the T-cell receptor beta-chain repertoire in Mitsuda reactions to determine the breadth of the mycobacterial antigens involved. The polymerase chain reaction was used to compare V beta usage in the Mitsuda reaction T-cell lines established and unstimulated peripheral blood. These molecular analyses revealed a skewed T-cell receptor V beta gene usage in the Mitsuda reaction and in T-cell lines from lesions. To examine the reactivity of T cells from these lesions, T-cell lines were tested against the available native and recombinant antigens of M. leprae. T-cell lines derived from Mitsuda reactions responded more strongly to the 10-kDa M. leprae antigen, a homolog of GroES in Escherichia coli, than to other M. leprae proteins. T-cell lines were also shown to proliferate strongly in response to the 17- and 3-kDa proteins. The pattern of the lymphokine mRNA of these cells was reminiscent of the pattern of murine TH1 cells, positive for interleukin-2 and gamma interferon and weakly positive for interleukin-4. These data indicate that a limited array of T cells, perhaps recognizing stress proteins, secrete a type 1 lymphokine profile in the DTH response to mycobacteria.

T-cell receptor V-gene usage in synovial fluid and synovial tissue from RA patients

The question of whether there is a preferential use of certain V genes in T cells entering an inflamed joint has hitherto been studied mainly using unfractionated cells from synovial fluid and tissue respectively, and no clear answer to the question has yet been provided. Concomitantly, evidence has been provided that the use of V genes may differ considerably between CD4+ and CD8+ T cells, and consequently that detection of biased V-gene expression within an inflammatory lesion may require separate analysis of the two T-cell subsets. In this paper we have therefore studied T-cell receptor V-gene expression in rheumatoid arthritis by means of double stainings of synovial fluid and blood for available anti-TCR monoclonal antibodies and antibodies to CD4 and CD8, respectively. Double stainings were also performed with anti-TCR antibodies and antibodies to activation markers HLA-DR and IL-2R. A certain bias towards the preferential use of certain V genes was seen particularly in the synovial fluid samples within both the CD4+ and CD8+ T-cell populations, but no uniform pattern was evident among the 35 patients investigated.

Induction of cytokines in human whole blood cultures by a mitogen derived from Mycoplasma arthritidis and by staphylococcal enterotoxin B

Mycoplasma arthritidis produces a so-far only partially characterized soluble material (MAS) that has a potent mitogenic effect on T lymphocytes of several species. Similar to staphylococcal enterotoxins and a number of related toxins secreted by other species of bacteria, nanogram quantities of these so-called superantigens are sufficient to induce significant amounts of cytokines in the supernatant of lymphocyte cultures. Induction of interleukin-6 (IL-6) by MAS in murine bone marrow-derived macrophages has recently been described. In our study, we examined the differential effects of MAS and Staphylococcus aureus enterotoxin B (SEB) on human blood cells. When compared to MAS, SEB induced a higher proliferative response and, accordingly, a higher release of IFN-gamma. In contrast, large amounts of the macrophage products IL-1, IL-6 and tumor necrosis factor alpha (TNF-alpha) were observed in supernatants of cell cultures stimulated with MAS, whereas only small amounts were induced by SEB. Staphylococci and mycoplasmas are responsible for a number of diseases with various symptoms in man and animals. Our results suggest that SEB and MAS show different qualities in lymphocyte and macrophage stimulation which may be relevant in the pathogenesis of diseases.

Bacterial toxin superantigens activate human T lymphocytes reactive with myelin autoantigens

Some bacteria that are common human pathogens produce protein toxins that are potent activators of human T lymphocytes expressing certain types of T-cell receptors. In this study we examined the ability of staphylococcal toxins to stimulate human T lymphocytes that also recognized the myelin autoantigens myelin basic protein and proteolipid protein. T-cell populations responding to myelin basic protein or proteolipid protein were isolated from 4 subjects including 1 individual with multiple sclerosis. All myelin antigen-specific T cells responded in proliferation studies to at least one of the nine superantigenic toxins used in this study. The superantigenic toxins were up to 7 x 10(5)-fold more potent in proliferation assays than the myelin antigens to which the T cells were initially sensitized. In addition, cytotoxic, myelin basic protein-reactive T lymphocytes lysed antigen-presenting cells incubated with superantigenic toxins. These findings demonstrate a mechanism by which some bacterial infections might produce activation of myelin basic protein- and proteolipid protein-reactive T lymphocytes and perhaps contribute to demyelinating disease in humans.

PCR-based analysis of the TCR repertoire in human autoimmune diseases

Characterization of T cells at sites of autoimmune damage has been difficult. Now, however, polymerase chain reaction (PCR)-based methods are being used to analyse T-cell receptor (TCR) gene expression in such lesions. Here, Christopher Marguerie, Claudio Lunardi and Alex So summarize and interpret the most recent findings and describe the current understanding of TCR usage in autoimmune diseases.

A persistent T cell expansion in the peripheral blood of a normal adult male: a new clinical entity?

A dramatic and persistent T cell expansion in a healthy adult male was initially identified, using anti-T cell receptor for antigen (TCR)-specific MoAbs. The expanded T cells were found to be expressing TCR containing V alpha 12.1 and V beta 5.2, and they composed approximately one third of all the CD8+ T cells. The cells were shown to be not only non-activated (HLA-DR-, IL-2R-) but also of 'virgin' cell type (CD45RA+/CD45RO-) and they persisted over the observation period of more than one and a half years. Various T and B cell markers, and all other laboratory and physical parameters analysed, were normal. The expanded CD8+ T cells were further characterized by polymerase chain reaction (PCR) amplification, using V beta- and C beta-specific primers, followed by hybridization with J beta-specific probes. Close to 90% of the V alpha 12.1+ V beta 5.2+ T cells were found to utilize the J beta 2.5 gene segment, thus strongly suggesting the expanded T cells to be monoclonal. The condition may constitute a T cell counterpart to 'monoclonal gammopathy of undetermined significance' (MGUS), and by analogy we suggest it should be designated 'monoclonal T cell expansion of undetermined significance' (MTUS).

Analysis of human T-cell receptor alpha-chain cDNAs isolated from peripheral blood mononuclear cells

T-cell receptor alpha-chain cDNA were generated from unstimulated peripheral blood mononuclear cells of a DR2,3,52a individual using a modified anchor PCR method. Fifty-six cDNA clones were identified representing 47 distinct T-cell receptor clonotypes and 26 VA loci. This analysis identified a new VA gene family VA30, and a new member of the VA6 gene family.

Superantigens

The endogenous superantigens (the enigmatic minor lymphocyte-stimulating antigens) have been identified; they are encoded by integrated mouse mammary tumor viruses. The retroviral superantigens appear to be transmembrane glycoproteins, and their highly variable extracellular carboxyl terminus is responsible for V beta interaction. In spite of intensive efforts the precise structure-function relationship for the superantigens is not yet clear. The most important consequences of the introduction of the superantigens in vivo are shock and T-cell depletion and anergy. The search for novel superantigens related to human diseases has started.

Restricted heterogeneity of T cell receptor transcripts in rheumatoid synovium

RA is characterized by massive proliferation of synovial tissue, accompanying infiltration of the tissue with CD4+ T lymphocytes, and a genetic linkage to the MHC antigen HLA-DR4. Since T cells are restricted by class II MHC molecules such as DR4, this suggests a direct role for these CD4+ cells in pathogenesis. To investigate T cell receptor (TCR) usage in RA, we used oligonucleotide primers specific for each of the major alpha and beta TCR subfamilies to amplify cDNA derived from whole synovium or synovial tissue T cell lines in a family-specific manner. Detection of amplified DNA was facilitated by utilizing oligonucleotide probes derived from the constant regions of the TCRs. The TCR repertoire present in the synovial T cell lines was quite heterogeneous, with an average of 15 alpha chains and 15.8 beta chains detected. When synovial tissue was analyzed, the predominant TCR subfamilies detected tended to be more restricted, with an average of 4.6 alpha chains and 8.6 beta chains detected. This compared with an average of six alpha chains and 12 beta chains in nonrheumatoid synovial samples. The average percentage of synovia positive per TCR beta family was significantly lower for RA versus non-RA specimens (46.1 vs 65.6%, P = 0.034). These findings indicate that while a polyclonal population of T cells is present in RA synovium, the predominant patterns of TCR transcript expression may be somewhat more restricted, suggesting that TCR-based therapy of RA is possible.

Expression of a transgenic T cell receptor beta chain enhances collagen-induced arthritis

SWR/J transgenic (tg) mice were generated expressing the TCR beta chain derived from an anticollagen type II (CII) arthritogenic T cell clone. The SWR/J strain was selected because it is resistant to collagen-induced arthritis (CIA) and lacks the V beta gene segment used by the T cell clone. Expression of the tg beta chain on all thymocytes and peripheral lymph node T cells led to a more efficient anti-CII immune response, but did not confer CIA susceptibility to SWR/J mice. Nevertheless, this tg beta chain enhanced predisposition to CIA as (DBA/1 x SWR) F1 beta tg mice were more susceptible than normal F1 littermates. Our results demonstrate that the expression of the tg beta chain contributes to CIA susceptibility, but by itself it is not sufficient to overcome CIA resistance in the SWR/J strain.

Transgenic domestic animals provide an animal model for rheumatoid arthritis

Production of transgenic domestic animals by microinjection of egg nuclei has permitted the introduction of exogenous genes into the transgenic animal. Pursell et al (1) report severe synovitis, cardiomegaly, dermatitis, renal disease and gastric ulcers in pigs with an expressed bovine growth hormone transgene. I have hypothesized that rheumatoid arthritis (RA) is a disease with initial symptoms to the gamete (2, 3). This hypothesis is supported by data showing a reduced rate of RA in women using oral contraceptives (4, 5) and remission of RA in pregnancy (6). RA in animals resulting from trauma to the gamete would be consistent with this hypothesis. This paper hypothesizes that some of the pathology associated with genetic engineering of livestock can be attributed to a rheumatoid arthritis-like spectrum of symptoms. This systemic reaction could be sufficiently similar to human RA to permit the transgenic pig to serve as an animal model of the disease.

The importance of the T cell in initiating and maintaining the chronic synovitis of rheumatoid arthritis

We hope that this short review has produced convincing, although indirect, evidence that in the case of rheumatoid synovitis, the T cell is the conductor of an orchestra playing a tune written by an antigen-presenting cell. The tune develops and becomes modified with time, so that it is difficult to discern with clarity much of the original melody. We believe that it may be possible to substitute a new score that will bring this symphony to a harmonious end. We also strongly believe that this is preferable to augmenting the string section or suppressing the percussion section of the orchestra in the vain hope that in the end harmony can be achieved. The final musical analogy must be the hope that the first page of the score can be found, so that we may discover the main theme, the leitmotif, of the rheumatoid-specific antigenic peptide.

Quantitation of T-cell receptor V beta chain expression on lymphocytes from blood, brain, and spinal fluid in patients with multiple sclerosis and other neurological diseases

Multiple sclerosis (MS) is an inflammatory, demyelinating disease of the central nervous system in which large numbers of T cells enter the brain and cerebrospinal fluid (CSF). To determine whether these cells represent restricted populations, we studied expression of T-cell receptor V beta chains on paired samples from the central nervous system and blood of patients with MS or other neurological diseases (OND) using a quantitative polymerase chain reaction. The distribution of V beta chain expression in blood was skewed, with a significant preponderance of message from V beta genes 1 through 8 (p = 0.0001). Such skewing was not present in samples from the CSF and brain. Patterns of V beta gene expression were different among paired samples from spinal fluid and blood and were relatively heterogeneous. Blood and CSF samples from a patient with acute meningitis were studied on two separate occasions. The patterns of V beta expression changed over 72 hours in both the blood and the CSF. With one exception, no oligoclonal populations of T cells were observed nor were there disease-specific patterns of V beta gene expression in the blood or CSF. Samples from 2 MS brains and 1 OND brain expressed patterns of V beta genes that were different and less heterogeneous than those in paired blood. In addition, expression of V beta 12 was remarkably increased in the 2 MS brains, suggesting a selective recruitment or expansion of T cells expressing this gene. These data demonstrate that populations of T cells from blood, spinal fluid, and brain differ from one another and can fluctuate during periods of acute inflammation.(ABSTRACT TRUNCATED AT 250 WORDS)

Management of early inflammatory arthritis. Intervention with immunomodulatory agents: T cell vaccination

Current theories of the aetiology of RA point to a central role for the trimolecular complex comprising the MHC class II molecule on the surface of the APC, the antigenic peptide and the TCR on the disease-inducing T cell. Thus the arthritogenic T cell is an important target for new therapy. However, it cannot be directly identified because the causative antigen is unknown, so indirect techniques such as TCV and TCR peptide vaccination are required. In TCV, T cells thought to mediate the disease, in an activated and attenuated form, are injected into the patient, who then develops a specific immune response against these pathogenic T cells. TCV has been shown to be effective in protecting against and treating a variety of animal models of autoimmune disease, including AA, EAE and IDDM in NOD mice. The vaccines initially comprised clones and lines of T cells shown to be capable of transferring the disease, but later unseparated LN cells were also shown to be effective, paralleling more closely the human situation. Interestingly, it has become clear that TCV does not create its own regulatory network but amplifies a natural immunoregulatory network which forms as the disease develops. The major stimulating moiety on the vaccinating T cell is its receptor (anti-idiotypic response), although there is also an anti-ergotypic (anti-activated T cell) response. For this reason the technique of TCR peptide vaccination was developed, which utilizes only a short peptide from the TCR of the disease-causing cells to stimulate an immune response against them. This is effective in the prevention and treatment of EAE, where there is a preferential usage of TCR-V beta 8 by encephalitogenic T cells. The application of both these techniques to human autoimmune disease is in its infancy. Studies of TCV in MS and RA have not shown clear-cut clinical benefit, although immunological changes have been observed; comparison of methodology with the animal work and assessment of results are complex and further studies are in progress. Studies of TCR peptide vaccination in MS and RA are handicapped by the lack of a consensus on TCR usage in these conditions, but a limited study is underway in MS.