Shared human T cell receptor V beta usage to immunodominant regions of myelin basic protein

T-cell receptor V-gene usage in synovial fluid lymphocytes of patients with chronic arthritis

In this study we analyzed the usage frequencies of the TCR V-gene segments by alpha beta+ T cells present in synovial fluid of 17 patients with chronic arthritis, including rheumatoid arthritis. The results of this study, obtained from semiquantitative PCR analyses, showed that in all patients most of the TCR V alpha- and V beta-gene segments could be detected both in fresh PBMCs and in fresh SFMCs. The relative frequencies of use of these V-region genes were variable between the different patients. Although there was some skewing of increased usage frequencies of particular TCR V alpha and V beta genes among SFMC-derived TCRs when compared with PBMCs, we could not correlate such increased TCR V-gene usage with the inflammation in the joints as a disease-specific marker.

Skewed T-cell receptor repertoire in genetically identical twins correlates with multiple sclerosis

Although the cause of multiple sclerosis (MS) is unknown, it is thought to involve a T cell-mediated autoimmune mechanism. Susceptibility to the disease is influenced by genetic factors such as genes of the HLA and T-cell receptor (TCR) complex. Other evidence for a genetic influence includes the low incidence in certain ethnic groups, the increased risk if there are affected family members and the increased concordance rate for disease in monozygotic twin pairs (26%), compared to dizygotic twins. Epidemiological studies indicate that there may be an additional role for environmental factors. Although the target antigen(s) are not yet identified, several myelin or myelin-associated proteins have been suspected, among them myelin basic protein. A lack of genetically comparable controls has impaired the analysis of the T-cell response in MS patients and caused disagreement on TCR usage in the disease. Here we analyse the role of TCR genes in MS by comparing TCR usage in discordant versus concordant monozygotic twins in response to self and foreign antigens. We find that after stimulation with myelin basic protein or tetanus toxoid, control twin sets as well as concordant twin sets select similar V alpha chains. Only the discordant twin sets select different TCRs after stimulation with antigens. Thus exogenous factors or the disease shape the TCR repertoire in MS patients, as seen by comparison with unaffected genetically identical individuals. This skewing of the TCR repertoire could contribute to the pathogenesis of MS and other T-cell-mediated diseases.

Clonal analysis of in vivo activated CD8+ cytotoxic T lymphocytes from a melanoma patient responsive to active specific immunotherapy

To study in vivo activated cytolytic T cells, CD8+ T cells clones were isolated from a melanoma patient (HLA A2, A11) treated with active specific immunotherapy for 5 years. CD8+ T lymphocytes, purified by fluorescence-activated cell sorting, were cloned directly from the peripheral blood without antigen-presenting cells in the presence of irradiated autologous melanoma cells and recombinant interleukin-2 (IL-2) and IL-4. These conditions were inhibitory to de novo in vitro immunization. Of the 28 cytolytic CD8+ T cell clones, 21 lysed the autologous melanoma cell line (M7) but not the autologous lymphoblastoid cell line (LCL-7) nor the two melanoma cell line, M1 (HLA A28) and M2 (HLA A28, A31), used to immunize the patient. The remaining 7 clones were also melanoma-specific, although their reactivities were broader, lysing several melanoma cell lines but not HLA-matched lymphoblastoid cells. Eight clones from the first group, ostensibly self-MHC-restricted, were expanded for further analysis. All expressed cluster determinants characteristic of mature, activated T cells, but not those of thymocytes, naive T cells, B cells or natural killer (NK) cells. They also expressed CD13, a myeloid marker. Of the 8 clones, 3 expressed both CD4 and CD8, but dual expression was not correlated with specificity of lysis. Two CD8+ and 2 CD4+ CD8+ clones were specific for the autologous melanoma cells, the other 4 were also reactive against other HLA-A2-positive melanomas. Cytotoxicity for both singly and doubly positive clones was restricted by HLA class I but not class II antigens. Analysis of the RNA expression of the T cell receptor (TCR) V alpha and V beta gene segments revealed heterogeneous usage by the A2-restricted clones and, perhaps, also by the broadly melanoma-specific clones. Apparent TCR-restricted usage was noted for the self-MHC-restricted clones; 2 of the 4 expressed the V alpha 17/V beta 7 dimer. Since the T cell clones were derived from separate precursors of circulating cytotoxic T lymphocytes (CTL), the V alpha 17/V beta 7 TCR was well represented in the peripheral blood lymphocytes of this patient. In summary, we show that melanoma cells presented their own antigens to stimulate the proliferation of melanoma-reactive CD8+ CTL. CTL with a range of melanoma specificities and different TCR alpha beta dimers were encountered in this patient, perhaps as a result of hyperimmunization.(ABSTRACT TRUNCATED AT 400 WORDS)

Clinical trials of interferons in multiple sclerosis. What have we learned?

Although multiple sclerosis (MS) is generally believed to be an immune-mediated disease, conventional therapy with ACTH, corticosteroids, or immunosuppressive drugs is unsatisfactory. Aside from their unpredictable therapeutic effects, these agents are potentially hazardous and can only be given for short periods of time. There is an urgent need for less toxic yet effective immunotherapy, that that can be administered early in the disease and continued indefinitely. Clinical trials of the interferons (IFNs) have not only led to a promising new approach to treatment, but have also stimulated basic research in the immunological mechanisms of underlying disease activity. Administration of IFN-gamma promotes exacerbations of MS, whereas recombinant IFN-beta has been shown, in controlled clinical trials, to suppress them. Other ongoing studies are likely to provide further information about its long-term therapeutic value. More importantly, laboratory studies performed in conjunction with these clinical trials have provided fresh insights into the pathogenesis of MS by revealing immunoregulatory mechanisms in which endogenous IFN-gamma, TNF-alpha, and other cytokines appear to play central roles. The 'Decade of the Brain' may therefore see answers both to the therapeutic dilemma of MS, and to more basic questions about the function of IFNs and other cytokines in activation and regulation of the disease process.

Spinal fluid lymphocytes from a subgroup of multiple sclerosis patients respond to mycobacterial antigens

Immune responses to heat shock or stress proteins are observed in several chronic autoimmune diseases. Such proteins are major antigens of many bacteria, especially mycobacteria. To determine whether immune responses to stress proteins occur in chronic inflammatory diseases of the central nervous system such as multiple sclerosis (MS) we measured proliferative responses of lymphocytes from spinal fluids and bloods of patients with MS and other neurological diseases to a sonicate of M. tuberculosis, an acetone extract of M. tuberculosis, a recombinant 65-kd heat shock protein of M. leprae, and tetanus toxoid as a control recall antigen. Significantly increased spinal fluid lymphocyte responses to mycobacterial sonicate, relative to responses from paired peripheral blood lymphocytes, were present in 14 of 20 specimens from patients with MS (p < 0.025) and 2 of 9 specimens from patients with other neurological diseases. Spinal fluid lymphocytes also responded to tetanus toxoid, but differences between blood and spinal fluid were not statistically significant. Lymphocytes from 1 patient with MS responded only to M. leprae. There were no proliferative responses to the M. tuberculosis acetone extract. When patients with MS were classified according to duration of disease (< 2- or > 2-yr duration) 9 of 10 patients with recent onset had cerebrospinal fluid cells that responded to M. tuberculosis compared with 5 of 10 with longer duration symptoms (p < 0.012). Our data suggest a selective recruitment and/or expansion of mycobacterial reactive cells to the central nervous system of a subpopulation of patients with MS.(ABSTRACT TRUNCATED AT 250 WORDS)

T lymphocyte lines and clones selected against synthetic myelin basic protein 82-102 peptide from Japanese multiple sclerosis patients

As has been indicated in experimental autoimmune encephalomyelitis (EAE), the application of synthetic peptides for the selection of T cell lines may provide new insights into the pathogenesis of multiple sclerosis (MS). We report here on T cell lines/clones generated from peripheral blood of MS patients against an immunodominant myelin basic protein (MBP) peptide 82-102. This study demonstrates that the selection of T cell lines against the MBP peptide is much more efficient than against whole MBP in generating a large panel of T cell lines/clones, and therefore provides a powerful strategy for studying autoimmune T cell repertoire in individual subjects. The peptide-selected lines and clones recognized MBP 82-102, shorter peptides MBP 89-101, 89-100 and guinea pig whole MBP mainly in the context of HLA-DR, but did not cross-recognize virus-derived peptides homologous to MBP 82-102. Seven out of ten clones were found to recognize MBP 82-102 in the absence of autologous antigen presenting cells (APC), and in three of the seven clones, specificity for MBP 82-102 could be demonstrated only in the absence of APC because of their strong reactivity against autologous APC. Two-color flow cytometry revealed that the clones were heterogeneous with regard to expression of CD4 and CD8 molecules. Overall, the clones selected by the peptide were rather heterogeneous in phenotype and function compared with those selected by whole MBP.

T-cell receptor genes in autoimmunity

T cells are primary participants in the pathogenesis of the MHC-dependent autoimmune diseases, and therefore, evidence for association of TCR V-gene repertoires with such disorders has been actively sought. With very few exceptions, no clear-cut evidence for correlation of particular RFLP-defined V-C-region genomic polymorphisms with autoimmune disease predisposition has thus far been demonstrated. With regard to TCR V-gene repertoires engaged in responses to autoantigens, restricted use of certain V beta and V alpha genes in response to myelin basic protein has been documented in animal models. In many spontaneous and experimentally induced animal and human autoimmune diseases, however, the picture is far from clear. Although dominance of certain TCR V genes has been noted, the clonal restrictions are not absolute; they differ from one study to another and from one patient to another. Such variations may be caused by MHC allele-dependent determinant selection mechanisms, secondary T-cell infiltrates in inflammatory sites, different patient populations and stages of disease, or the involvement of different pathogens that, nevertheless, lead to the same clinical entity. Overall, the results indicate that efforts to intervene therapeutically in autoimmune diseases by vaccination with modified T-cell clones, V region-synthetic peptides, or TCR blocking analogues may not be easily applicable. Further studies on the characterization of the specific antigens involved in autoimmune disease pathogenesis is required in order to accurately address the issue of TCR utilization in autoimmune diseases.

Cellular basis of T-cell autoreactivity in autoimmune diseases

There is no doubt that T cells play a key role in the pathogenesis of autoimmune diseases (AD) both as effector and regulatory cells. Despite spectacular progress in the understanding of natural tolerance to self, owing particularly to transgenic technology, important questions remain open regarding the pathogenesis of AD, the conditions favoring the transition from benign or 'physiological' autoimmunity to deleterious autoimmunity, and the precise effector mechanisms. This review on the cellular basis of T-cell-mediated AD begins with an enumeration of the main arguments in favor of direct T-cell involvement, special emphasis being given to two animal models which have been most extensively investigated: experimental allergic encephalomyelitis, and the nonobese diabetic mouse. The question as to whether pathogenic T cells use a restricted repertoire of V beta genes is examined in the context of these two models. From here we proceed to an evaluation of the mechanisms of onset of AD, discussing both extrinsic and intrinsic factors responsible for the breakdown in T-cell tolerance and reviewing the arguments in favor of suppressor T cells being actively involved in the prevention of autoimmunity. The last two sections are devoted to the effector mechanisms responsible for tissue injury in organ-specific AD and to T-cell-directed therapeutic interventions, respectively. We discuss the two main pathogenic hypotheses based on direct intervention of cytotoxic T cells or indirect involvement of inflammatory cytokines and macrophages, and evaluate the importance of ecotaxis in leading autoreactive T cells to the site of injury. We conclude on a brief and nonexhaustive list of strategies aimed at selectively neutralizing potentially harmful T cells.

T cell receptor V beta repertoire in HIV-infection individuals: lack of evidence for selective V beta deletion

The gradual decline of CD4+ T lymphocytes in HIV-infected individuals culminates in the lethal immunosuppression of AIDS. The mechanism of CD4+ T cell loss is currently unknown, but has recently been suggested to occur as a result of an HIV-encoded superantigen which facilitates a selective deletion of T cells expressing specific V beta genes. To verify and extend such observations, peripheral blood leucocytes (PBL) from 15 HIV+ individuals, 10 of which had very low CD4 T cell counts (< 200/mm3), were analysed for T cell receptor (TCR) V beta gene expression. In contrast to a recent study, the results presented here fail to provide evidence that selective loss of V beta-bearing T cells occurs in HIV+ individuals. Furthermore, when PBL from HIV+ individuals were stimulated with Staphylococcal enterotoxin B (SEB), T cells expressing V beta subfamilies known to engage this superantigen were expanded, indicating that such cells were not deleted and were responsive to stimulation by a bacterial superantigen. Collectively, these data suggest that CD4 loss in HIV patients does not occur in a V beta-selective, superantigen-mediated fashion.

Analysis of T cell receptor repertoire of muscle-infiltrating T lymphocytes in polymyositis. Restricted V alpha/beta rearrangements may indicate antigen-driven selection

Polymyositis is an inflammatory myopathy characterized by mononuclear cell infiltration of muscle tissue. Myocytotoxic T lymphocytes have been recognized in the infiltrates, but the muscle antigen, target of the immune attack, has not been identified. Molecular characterization of the variable regions of T cell receptors (TCRs) on the infiltrating lymphocytes can be expected to provide insights into the pathogenic process. The V alpha/beta TCR repertoire was investigated by RNA-PCR in muscle biopsies from 15 polymyositis patients and 16 controls (6 Duchenne muscular dystrophy and 10 with no inflammatory or dystrophic myopathy). A variety of rearranged variable TCR genes was found in polymyositis, V alpha 1, V alpha 5, V beta 1, and V beta 15 being the most common (present in 60-100% of patients). In Duchenne muscular dystrophy patients TCR V alpha or beta rearrangements were found although no restriction was observed; no rearrangements were found in muscles from the other controls. Sequence analysis revealed the presence of the J beta 2.1 region in 90% of the V beta 15 clones studied, no random N additions in the diversity region, and a common motif within the CDR3 region. These results suggest that selection of muscle-infiltrating T lymphocytes is antigen driven in polymyositis.

Inflammation and the brain

Inflammation in the brain selectively damages the myelin sheath resulting in a variety of clinical syndromes of which the most common is multiple sclerosis. In these disorders, the areas of inflammation and demyelination can be identified in life by magnetic resonance imaging. Events occurring at the blood-brain barrier depend on T-cell activation, which increases immune surveillance within the central nervous system. T-cells activated against brain antigens persist to establish the conditions needed for inflammatory demyelination and this depends on local release of cytokines, culminating in removal of oligodendrocytes and their myelin lamellae by macrophages or microglia. These interactions involve binding between receptors present on microglia for the Fc portion of antibody and complement components to corresponding ligands on target cells. Taken together, the evidence from clinical and experimental studies provides a rationale for the issue of immunological treatments in patients with multiple sclerosis.

The human T-cell receptor beta-chain repertoire: longitudinal fluctuations and assessment in MHC matched populations

The influence of the environment and of the major histocompatibility complex (MHC) in shaping the human T-cell receptor beta-chain variable region (TCRBV) repertoire has not been systematically studied. Here, expression of TCRBV gene families was estimated by a sensitive polymerase chain reaction (PCR)-based method. Serial studies of peripheral blood, performed at 2-week intervals over a 3-month period, revealed that fluctuation in the expression of many TCRBV genes occurred in healthy individuals and in the absence of clinically evident infections. Fluctuation of TCRBV4, TCRBV5.2, TCRBV9, and TCRBV13.1 genes were present in all subjects. Additional TCRBV genes fluctuated in some but not in other individuals. Comparison of the TCRBV repertoire between these unrelated individuals indicated differences in the mean expression of TCRBV5.1, TCRBV9, TCRBV11, TCRBV15, TCRBV17, and TCRBV20 genes. For any TCRBV gene, intersubject differences were generally of a magnitude of twofold or less. Larger differences characterized the TCRBV repertoire of CD4 compared to CD8 cells. Some differences, for example over-representation of TCRBV2 and TCRBV5.1 on CD4, and TCRBV10, TCRBV14, and TCRBV16 on CD8 cells, were present in most subjects. Individuals homozygous for DR2- or DR3-bearing extended MHC haplotypes displayed similar individual variability of TCRBV expression. These data indicate that the circulating TCRBV repertoire in humans is both dynamic and diverse. Both environment and MHC effects contribute to the diversity of TCRBV expression.

Quantitative measurement of human T-cell receptor V beta subfamilies by reverse transcription-polymerase chain reaction using synthetic internal mRNA standards

Quantitative determination of T-cell receptor (TCR) V beta expression is necessary to define the changes in TCR-V beta subfamily expression that occur during T-cell maturation and selection and to detect alterations of the TCR-V beta repertoire that may be associated with human diseases. Here we describe and validate a quantitative reverse transcription-polymerase chain reaction (RT-PCR) technique to determine human TCR-V beta subfamily mRNA levels (as well as other mRNA species), based on the use of synthetic poly(A) mRNA internal standards that are coprocessed with native (sample) mRNA transcripts. The technique allows simultaneous reverse transcription of sample and standard mRNA and thus obviates errors arising during reverse transcription. In addition, the technique allows coamplification of several concentrations of standard mRNA (cDNA) with sample mRNA (cDNA) under conditions in which these mRNAs amplify with equal efficiency; thus, it avoids errors resulting from saturation of competition effects. Finally, the technique is sensitive to lower than 1.5-fold differences in input mRNA. To apply the technique, we also describe methods for the generation of poly(A) mRNA internal standards that can be used to quantitate TCR-V beta 2/6/7 and TCR-C beta mRNA.

Endogenous antigen presentation by autoantigen-transfected Epstein-Barr virus-lymphoblastoid cells. I. Generation of human thyroid peroxidase-reactive T cells and their T cell receptor repertoire

To develop a model for endogenous thyroid autoantigen presentation, we transfected EBV-transformed B lymphoblastoid cell lines (EBV-LCL), established from patients with autoimmune thyroid disease and normal controls, with cDNA for the human thyroid autoantigen thyroid peroxidase (hTPO). hTPO-antigen presentation to patient peripheral blood T cells was demonstrated after stimulation in vitro for 7 d with irradiated hTPO-transfected or untransfected autologous EBV-LCL. Anti-hTPO-reactive T cells were subsequently cloned in the presence of irradiated, autologous hTPO-transfected EBV-LCL and IL-2.10 T cell-cloned lines exhibited specific hTPO-induced proliferation (stimulation indices of 2.1-7.9) towards autologous hTPO-transfected EBV-LCL, and were subjected to human T cell receptor (hTCR) V gene analysis, using the PCR for the detection of V alpha and V beta hTcR gene families. The results indicated a preferential use of hTCR V alpha 1 and/or V alpha 3 in 9 of the 10 lines. In contrast, hTCR V beta gene family use was more variable. These data demonstrate a model for the endogenous presentation of human thyroid peroxidase in the absence of other thyroid specific antigens. The high frequency of antigen-specific T cells obtained from PBMC using this technique will facilitate further studies at both the functional and hTCR V gene level.

Epitope specificity and V gene expression of cerebrospinal fluid T cells specific for intact versus cryptic epitopes of myelin basic protein

Recent evidence supports the possible involvement of myelin basic protein (BP) as one of the target autoantigens in multiple sclerosis (MS), including elevated frequencies of MS blood and cerebrospinal fluid (CSF) T cells, and the presence in MS plaque tissue of V beta gene sequences and CDR3 motifs characteristic of BP-reactive T cells. Because of its proximity to the target organ, the CSF has long been thought to harbor T cells involved in the pathogenic process. In order to evaluate their frequency and response characteristics, BP-reactive T cells were isolated by limiting dilution from the CSF of patients with MS and other neurological diseases (OND) for quantitation and determination of epitope specificity and V alpha and V beta gene expression. In addition to isolates responsive to intact BP epitopes that were present at a significantly higher frequency in MS versus OND CSF, we here describe a second clonotype responsive to 'cryptic' BP epitopes that is present at approximately equal frequencies in MS and OND patients. In spite of their difference in recognition of intact versus 'cryptic' BP determinants, both clonotypes predominantly recognized epitopes in the N terminal half of human BP, using a similar V gene repertoire that included biased use of V alpha 2 and to a lesser degree V beta 7 and V beta 18. These V gene biases were not related to the epitope specificity of the T cells, indicating that V gene selection is not epitope-driven. These data suggest that there is differential recognition of intact versus 'cryptic' BP determinants in MS versus OND patients that may be related to the processing and presentation of BP to the immune system.

Target epitopes of myelin basic protein specific T cell lines in multiple sclerosis

A highly efficient new method for the generation of antigen specific T cell lines (TCL) is now available. By this method we established 134 myelin basic protein (MBP) TCL from the peripheral blood of 9 patients with definite multiple sclerosis (n = 69) and 8 healthy donors (n = 65). The yield of MBP reactive TCL in the two groups was comparable. So far 22 MBP specific TCL from 7 patients and 24 from 7 healthy individuals have been tested for their proliferative response to a panel of four synthetic peptides representing MBP residues 7-26, 80-99, 139-153 and 148-162. Although the peptide sequences did not encompass the whole MBP, the pattern of reactivity to these peptides in patients and controls seems to be similar. Further, when multiple TCL from the same donor were analysed, no dominant recognition emerged.

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.

Binding of myelin basic protein peptides to human histocompatibility leukocyte antigen class II molecules and their recognition by T cells from multiple sclerosis patients

Multiple sclerosis (MS) is an autoimmune disease in which myelin proteins have been implicated as autoantigens recognized by pathogenic autoreactive T cells. To study the relationship between human myelin basic protein (hMBP) and HLA alleles associated to MS susceptibility, such as DRB1*1501, the binding of synthetic peptides spanning the entire hMBP sequence to 10 purified HLA-DR molecules was determined. All the hMBP peptides tested showed binding affinity for at least one of the DR molecules analyzed, but three hMBP peptides, included in sequences 13-32, 84-103, and 144-163 were found capable of binding to three or more DR molecules. The hMBP peptide 84-103 was the most degenerate in binding, in that it bound to 9 out of 10 DR molecules tested. Interestingly, it bound with highest affinity to DRB1*1501 molecules. To correlate the binding pattern of hMBP peptides to HLA class II molecules with their recognition by T cells, 61 hMBP-specific T cell lines (TCL) were established from the peripheral blood of 20 MS patients, who were homozygous, heterozygous, or negative for DRB1*1501. Analysis of hMBP epitopes recognized by these TCL and their HLA restriction demonstrated a very good correlation between binding data and T cell proliferation to hMBP peptides. Although virtually all hMBP peptides tested could be recognized by at least one TCL from MS patients, three immunodominant T cell epitopes were apparent among the TCL examined, corresponding exactly to the hMBP peptides capable of binding to several DR molecules. No major difference could be detected in the recognition of immunodominant hMBP peptides by TCL from DRB1*1501 positive or negative MS patients. These results have implications for the role of hMBP as relevant autoantigen, and of DRB1*1501 as susceptibility allele in MS.

Human T cell autoimmunity against myelin basic protein: CD4+ cells recognizing epitopes of the T cell receptor beta chain from a myelin basic protein-specific T cell clone

We have investigated whether the normal immune system contains T cells that are able to recognize T cell receptor (TcR) determinants of autologous autoantigen-specific T cells. The T cell clone HW.BP3, specific for myelin basic protein (MBP) was isolated from a healthy donor. HW.BP3 is restricted by HLA-DR2a, and reacts to human MBP 139-153. The expressed alpha beta TcR genes of HW.BP3 were cloned and sequenced, and the sequences analyzed for potential T cell epitopes. Two synthetic peptides, one from the VDJ beta junctional (beta 1) and one from the V beta region (beta 2) of the TcR of HW.BP3, were used to select four TcR peptide-specific T cell lines from the donor of HW.BP3. All anti-TcR lines had the phenotype CD3+/CD4+/HLA-DR+/CD25+/CD45RO+, and recognized the antigen in the context of HLA-DR. Three anti-TcR lines, which had been selected for reactivity to peptide beta 1, recognized exclusively this peptide restricted by HLA-DR2b. One anti-TcR line, selected for peptide beta 2, responded to both peptides beta 1 and beta 2 when presented by autologous blood mononuclear cells, but not by HLA-DR2a- or HLA-DR2b-transfected L cells. All TcR peptide-specific T cell lines were efficiently cytotoxic. They specifically lysed autologous macrophages or HW.BP3 line cells in the presence of exogenous peptide antigen. In contrast, HW.BP3 did not present endogenous TcR peptides to the anti-TcR lines. The results demonstrate that the normal human immune system contains not only autoantigen-specific T cells, but also T cells that recognize antigenic determinants of autologous autoreactive TcR.

Human fetal liver gamma/delta T cells predominantly use unusual rearrangements of the T cell receptor delta and gamma loci expressed on both CD4+CD8- and CD4-CD8- gamma/delta T cells

Substantial numbers of both alpha/beta and gamma/delta T cells are present in human fetal liver, which suggests a role of the fetal liver in T cell development. The diversity of fetal liver T cell receptor (TCR) gamma and delta chain rearrangements was examined among both CD4+CD8- and CD4-CD8- gamma/delta T cell clones. In addition, TCR delta chain transcripts from three fetal livers were sequenced after polymerase chain reaction amplification of TCR delta chains with V delta 1 or V delta 2 rearrangements. Five of six fetal liver gamma/delta T cell clones had a V delta 2-D delta 3-J delta 3 gene rearrangement with limited junctional diversity; three of these clones had an unusual CD4+CD8- phenotype. V delta 2-D delta 3-J delta 3 gene rearrangements were also common among both in-frame and out-of-frame transcripts from three fetal livers, indicating that they are the result of an ordered rearrangement process. TCR gamma chain sequences of the fetal liver gamma/delta T cell clones revealed V gamma 1-J gamma 2.3, V gamma 2-J gamma 1.2, and V gamma 3-J gamma 1.1 rearrangements with minimal incorporation of template-independent N region nucleotides. TCR gamma chain rearrangements found in these fetal liver T cell clones were different from those that have been observed among early thymic gamma/delta T cell populations, while similar TCR delta chain rearrangements are found among gamma/delta T cells from both sites. These data demonstrate that the fetal liver harbors gamma/delta T cell populations distinct from those found in the fetal thymus, suggesting that the fetal liver is a site of gamma/delta T cell development in humans. These unusual T cell populations may serve a specific function in the fetal immune system.

Clonal expansions of activated gamma/delta T cells in recent-onset multiple sclerosis

Multiple sclerosis (MS) is a chronic disease characterized by focal demyelination of the white matter of the brain and spinal cord. Central nervous system damage appears to be mediated by infiltrating T lymphocytes and macrophages, and a central role for autoreactive CD4+ T cells has been proposed. However, the initial immune events that lead to the chronic process of MS remain unidentified. We now present evidence that a subset of T lymphocytes bearing gamma/delta T-cell antigen receptors has been activated in patients with recent-onset disease. Cells recovered from the cerebrospinal fluid of subjects with MS were cultured for short periods of time in medium supplemented with T-cell growth factors. Expansions of V delta 1 and V delta 2 T-cell receptor-bearing lymphocytes were found only in cell populations obtained from subjects with recent-onset disease. Similar populations were not expanded in subjects with chronic MS or other neurological diseases. Junctional region sequencing showed the expanded gamma/delta T cells to be oligoclonal in nature, suggestive of specific stimulation by antigen. These results reveal a fundamental difference in the immunopathogenesis of acute vs. chronic disease and provide additional insight into the autoimmune nature of MS.

A functional basis for the association of HLA class II genes and susceptibility to multiple sclerosis: cellular immune responses to myelin basic protein in a multiplex family

This study has examined the cellular response to myelin basic protein (MBP) in a multiplex family with multiple sclerosis (MS). A total of 81 MBP-specific T cell lines (TCLs) were derived from three affected siblings and four healthy siblings. No difference was observed in estimated precursor frequencies of MBP-specific TCLs or peptide specificity of TCLs when comparing affected and unaffected siblings. MBP-specific TCLs from affected siblings, however, were restricted to the DRw15/DQw6 allele more frequently than those from unaffected siblings (P < 0.02). These data suggest that restriction of autoantigen-specific T cells may be the functional basis for disease susceptibility related to HLA class II inheritance.

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.

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.

Multiple sclerosis: an autoimmune disease of multifactorial etiology

The etiology of multiple sclerosis is linked to a variety of genetic and environmental factors. Both cell-mediated and humoral immune responses, triggered by extraneous or autoantigens, are likely to contribute to the pathogenesis of this disease. A greater insight into the fundamental cause of multiple sclerosis has been provided by the recognition that certain immune response genes are associated with an increased susceptibility to the disease. Such knowledge should provide new opportunities for selective therapeutic interventions.

T-cell receptor beta-chain gene usage in the T-cell recognition of Mycobacterium leprae antigens in one tuberculoid leprosy patient

The beta chain of the T-cell antigen receptor present on 20 T-cell clones isolated from a tuberculoid leprosy patient was studied by gene rearrangement and PCR analysis. These T-cell clones all responded to Mycobacterium leprae-encoded protein antigens, and 8 of them specifically recognized peptides of the mycobacterial 65-kDa heat shock polypeptide (65hsp). All T-cell clones studied were HLA-DR-restricted (DR2 or -3). In the DR3-restricted group, 7 of 10 used a beta-chain variable region V beta 5 gene family member, whereas in the DR2-restricted group, 2 of 10 T-cell clones used a V beta 5 gene segment and 5 used the V beta 18 gene segment. The deduced amino acid sequences of the beta chain from 8 T-cell clones have revealed that 3 of 4 DR3-restricted T-cell clones expressed the V beta 5.1 gene segment whereas the fourth DR3-restricted T-cell clone employed a V beta 5 family member not previously described. The V beta 5.1-positive T-cell clones all recognized the same 65hsp peptide from residues 2 to 12. The N-D-N segment (where D is diversity) of the junctional region of these T-cell clones was very similar, despite different beta-chain joining gene segments. Of the 4 DR2-restricted T-cell clones investigated, 3 used the V beta 18 gene segment and recognized the 65hsp peptide from residues 418 to 427. In conclusion, within this panel of M. leprae-reactive T-cell clones, the DR3-restricted T-cell clones mainly used a V beta 5 gene segment, whereas the DR2-restricted clones employed preferentially the V beta 18 gene segment.

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.

Specific DNA amplification utilizing the polymerase chain reaction and random oligonucleotide primers: application to the analysis of antigen receptor variable regions

The polymerase chain reaction (PCR) allows rapid amplification of DNA of known sequence. In many situations, part of a genetic sequence is known, but adjacent sequences of interest are unknown. This is common in investigations of antigen receptor genes from B and T lymphocytes, which are composed of a constant region of known sequence and a variable region, for which the sequence may not be known. Herein is described a method to amplify DNA when sequence information is available for only one primer. This procedure utilizes a primer of known sequence in conjunction with a mixture of short random primers. Application of this method to the amplification of T-cell antigen receptor cDNA is described.

Predominant usage of V beta 8.3 T cell receptor in a T cell line that induces experimental autoimmune uveoretinitis (EAU)

Experimental autoimmune uveoretinitis (EAU) is a T cell-mediated autoimmune disease induced in animals by immunization with retinal proteins (or synthetic fragments derived from them) in adjuvant, and it is considered a model of human autoimmune diseases of the eye. To study the T cell clonotypes that may be involved in EAU, we analyzed the T cell repertoire of three related T cell lines: the pathogenic line LR16, specific to the major uveitogenic epitope of IRBP; its pathogenic subline J; and its nonpathogenic subline A. We examined the expression of the genes coding for the variable regions of the 20 known Lewis rat T cell antigen receptor (TCR) V beta families. The nonpathogenic subline was found to contain mostly T cells expressing V beta 5, V beta 8.2, and V beta 19 while the pathogenic subline consisted mainly of cells expressing V beta 8.3 TCRs. Genomic Southern blot analysis of DNA from the pathogenic subline showed that V beta 8.3-expressing T cells were the dominant clonotype, and DNA sequence analyses of V beta 8.3 cDNAs revealed that two V beta 8.3 TCRs were expressed in the pathogenic subline. One of the V beta 8.3 cDNAs encoded a variable region gene segment identical to previously reported rat V beta 8.3 TCR while the other differed by two amino acids in the second complementarity determining region (CDR2). Taken together with previous data showing overrepresentation of V beta 8-expression in T cell lines that induce EAU, but not in nonuveitogenic T cell lines, our results suggest that V beta 8.3-expressing T cells represent a pathogenic clonotype in IRBP-induced EAU.

Limited heterogeneity of T cell receptor variable region gene usage in juvenile rheumatoid arthritis synovial T cells

The aim of this study was to determine whether synovial fluid (SF) T cells in patients with juvenile rheumatoid arthritis (JRA) are restricted in their T cell receptor (TcR) gene repertoire. The quantitative polymerase chain reaction (QPCR) was used to compare the transcription of V beta and V alpha gene families in freshly isolated SF T cells, in interleukin-2 receptor-positive (IL-2R+) T cells and in peripheral blood (PB) T cells from 18 patients. Significantly less V beta families are detected in SF when compared with PB (p greater than 0.0003). The TcR V beta gene usage by IL-2R+ T cells was even less heterogeneous when compared with freshly isolated SF T cells (p greater than 0.0002). Freshly isolated SF T cells from the left and the right knees of four patients transcribed the same V beta families. Furthermore, we demonstrate that in SF the distribution of certain TcR V beta gene segments in CD4+ and CD8+ T cells differed from that in PB of the same patient. The TcR V alpha usage was studied in IL-2R+ T cells from six patients who had shown restriction in their SF TcR V beta gene usage. Only two to five TcR alpha transcripts were detected in three of these patients while a broad TcR V alpha usage was seen in the other three patients. Sequence analysis of the SF V beta 20 cDNA clones generated from the IL-2R+ T cells of two patients demonstrated an oligoclonal expansion. Taken together, our data could indicate an antigen- and/or superantigen-driven expansion of selected T cells in the synovial compartment.

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.

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.

Transfer of multiple sclerosis into severe combined immunodeficiency mice by mononuclear cells from cerebrospinal fluid of the patients

To investigate the mode of the pathogenesis of multiple sclerosis (MS), we transferred cerebrospinal fluid (CSF) cells, predominantly mononuclear cells, from MS patients at both exacerbation and remission stages of the disease into severe combined immunodeficiency mice by intracisternal injection. As controls, (i) CSF cells from patients with cervical spondylosis and (ii) peripheral blood mononuclear cells from normal individuals were transferred. Four to 6 weeks after transfer, most mice transferred with CSF cells from MS patients at the exacerbation stage of the disease developed paralysis and ataxia. The histopathological examination on the sacrificed mice revealed multiple scattered, discrete lesions localized in the white matter of the brainstems and spinal cords. These lesions were characterized by various degrees of tissue necrosis, involving inflammatory-cell infiltration. Most infiltrating cells were macrophages, although a smaller number of granulocytes appeared in several foci. Reactive astrocytic gliosis was also seen around the necrotic foci. Furthermore, these lesions exhibited demyelination. These histopathological changes are similar to those seen in MS. In contrast, none of the severe combined immunodeficiency mice transferred with CSF cells from MS patients at the remission stage of the disease, or with CSF cells from the patients with cervical spondylosis, or with peripheral blood mononuclear cells from normal individuals showed any such histopathological changes. These observations provide convincing direct evidence of encephalitogenicity of mononuclear cells in CSF from MS patients at the exacerbation stage of the disease.

Development of the non-palindromic adaptor polymerase chain reaction (NPA-PCR) for the amplification of alpha- and beta-chain T-cell receptor cDNAs

We have developed a highly efficient new method for the amplification of alpha- and beta-chain human T-cell receptor (TCR) cDNAs. This method is designated non-palindromic adaptor polymerase chain reaction (NPA-PCR). cDNA was synthesized from total RNA isolated from mononuclear leucocytes, using either an oligo (dT)15-NotI or a C alpha-NotI or a C beta-NotI primer and RNase H-negative reverse transcriptase. The double-stranded cDNA was ligated with the non-palindromic adaptors EcoRI-XmnI [d(ATTCGAACCCCTTCG)] and XmnI G strand [d(pCGAAGGGGTTCG)] (phosphorylated), which resulted in the addition of the EcoRI-XmnI site in both 5' and 3' ends. These two non-palindromic adaptors, EcoRI-XmnI and XmnI G strand, are complementary to each other and both are required for ligation. The EcoRI-XmnI adaptor was removed from the 3' end by treatment with NotI restriction nuclease, whereas it was retained at the 5' end. The non-palindromic adaptor EcoRI-XmnI was used as the 5' amplification primer. C alpha or C beta constant region primers were used as 3' amplification primers. The amplified cDNAs were cloned and the plasmids were used to transform DH5 alpha competent cells. Over 1000 white colonies per 0.1-0.25 micrograms of total RNA or per 10,000 to 50,000 human peripheral blood mononuclear cells were obtained after amplification of either the alpha- or the beta-chain TCR cDNAs. Between 40 and 62% of the colonies (range from five donors) were positive after screening with either a C alpha or a C beta probe, located 5' to the C alpha and C beta amplification primers. A total of 50 amplified alpha- or beta-chain cDNA positive clones from two normal donors were randomly chosen and sequenced, and the sequences obtained were typical of alpha beta TCR. Two new J alpha gene segments were identified. Approximately 30% of the alpha-chain positive clones have 5' untranslated region, and most of the remaining alpha- or beta-chain TCR clones started from the initiation codon or near the 5' end. NPA-PCR has several advantages over existing PCR methods for the amplification of cDNAs with unknown or variable 5' end, such as the T-cell antigen receptors and the immunoglobulins. Among these advantages is that only one 5' end extension primer is required. Because of the large number of TCR V alpha and V beta families, a large number of different 5' end primers are required for amplification of alpha beta TCR cDNAs by conventional PCR.

Selective manipulation of the human T-cell receptor repertoire expressed by thymocytes in organ culture

A recently described organ culture system for human thymocytes is shown to support the generation of a diverse T-cell receptor repertoire in vitro: thymocytes of the alpha beta lineage, including representatives of the V beta families 5.2/5.3, 6.7, and 8, accounted for the majority of T-cell receptor-positive cells throughout a 3-week culture period. Thymocytes bearing gamma delta receptors were also identified, particularly among the CD4 CD8 double-negative subset. The T-cell receptor repertoire expressed in organ culture responded to experimental manipulation with staphylococcal enterotoxins. Staphylococcal enterotoxin D (a powerful activator of human peripheral T cells expressing V beta 5.2/5.3 receptors) caused a marked reduction of V beta 5.2/5.3 expression, as determined with the V beta-specific antibody 42/1C1. Evidence is presented that this loss of V beta 5.2/5.3 expression resulted from the selective deletion of activated thymocytes by apoptosis, in concert with T-cell receptor modulation. These effects of staphylococcal enterotoxin D were specific (since staphylococcal enterotoxin E did not influence V beta 5.2/5.3 expression) and V beta-selective (since expression of V beta 6.7 remained unaffected by staphylococcal enterotoxin D). On the basis of these observations, we suggest that thymic organ culture provides a powerful approach to study the generation of the human T-cell repertoire.

In situ islet T cell receptor variable region gene usage in the nonobese diabetic mouse

Several features of the genetics and immunopathology of diabetes in the nonobese diabetic (NOD) mouse, which spontaneously develops type I diabetes, are shared with the human disease. Immunohistochemical studies support the concept that T lymphocytes are the major components of inflammatory cells in the pancreatic islets and these cells may play a critical role in the destruction of the beta cells leading to diabetes. Therefore, we examined whether particular TCR-beta variable region genes were utilized by in situ islet T cells at different stages (4 - 5, 7, 14 - 15 and 16 weeks of age) of the disease process. Dot-blot hybridization was performed using RNA prepared from isolated islets, thymus, spleen, peripheral blood leukocytes and axillary lymph nodes of 10 to 15 mice pooled for each data point. Ten different TCR V-beta probes were used for the analyses. Limited usage of islet V-beta genes was observed only at the early prediabetic stage (4 - 5 weeks old) of the disease. At later stages of the disease (7 - 16 weeks old), no preferential usage of TCR genes was observed in the islets compared to those of peripheral lymphoid organs. These data suggest that only certain types of T cells bearing particular TCR V-beta genes may be responsible for initiating and perpetuating infiltration of immune cells into the islets and these particular T cells are only identified at the very early stages of the autoimmune process.

Frequency of T cells specific for myelin basic protein and myelin proteolipid protein in blood and cerebrospinal fluid in multiple sclerosis

T cell sensitization to two myelin components, myelin basic protein (MBP) and myelin proteolipid protein (PLP), may be important to the pathogenesis of multiple sclerosis (MS). Using the limiting dilution assay, we demonstrated that the blood of MS patients had an increased frequency of MBP-reactive T cells compared with normal subjects and patients with other neurological diseases (OND) and rheumatoid arthritis. There was no difference in T cell frequency to a synthetic peptide, PLP139-151, or Herpes simplex virus. Within cerebrospinal fluid (CSF), 37% of IL-2/IL-4-reactive T cell isolates from MS patients responded either to MBP or PLP139-151 while only 5% of similar isolates from OND patients responded to these myelin antigens. The mean relative frequency of MBP-reactive T cells within CSF from MS patients was significantly higher than that of OND patients (22 x 10(-5) cells versus 1 x 10(-5) cells) and was similar to that of MBP reactive T cells within the central nervous system of rats with experimental autoimmune encephalomyelitis. These results lend new support to the hypothesis that myelin-reactive T cells mediate disease in MS.

T cell receptor V alpha-V beta repertoire and cytokine gene expression in active multiple sclerosis lesions

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system with presumed autoimmune etiology. A recent study has suggested the presence of a restricted T cell receptor (TCR) V alpha repertoire in MS lesions. The presence of such a restricted TCR repertoire at the site of inflammation would have important consequences for the pathogenesis and the ultimate treatment of MS. To further characterize the TCR V alpha and V beta repertoire in MS plaque tissue, we examined a series of 26 histologically well-characterized central nervous system (CNS) tissue specimens from six MS patients as well as samples from five normal postmortem cases and a case of subacute sclerosing panencephalitis. RNA was extracted from frozen sections and cDNAs were amplified by polymerase chain reaction using primers for TCR V alpha (V alpha 1-18) and V beta (V beta 1-19) gene families. This analysis demonstrated a broad TCR V alpha-V beta repertoire in active lesions, while fewer TCR V genes were detected in chronic plaques and control samples. Even though a large number of TCR V alpha and V beta gene segments were present in the majority of active lesions, there were clear differences in the TCR repertoire between plaques from the same case, suggesting that local events influence the TCR repertoire at the level of T cell recruitment or T cell expansion. Examination of cytokine mRNAs demonstrated that IL-1 mRNA was present in the majority of acute and subacute plaques, while IL-2 and IL-4 mRNA were detected in only a few acute lesions. These data demonstrate that the TCR repertoire in MS plaques is polyclonal. However, autoreactive alpha/beta T cells thought to be critical in the initiation of the inflammatory process probably represent a minor fraction of T cells in active MS plaques and may use a limited number of TCR V gene segments for recognition of the autoantigen.

Studies of V beta 8 T cell receptor peptide treatment in experimental autoimmune encephalomyelitis

Lewis rats immunized with T cell receptor (TCR) variable region peptide V beta 8 in complete Freund's adjuvant (CFA) were protected against experimental autoimmune encephalomyelitis (EAE) induced with myelin basic protein in CFA, although variable protection was also observed in rats injected with control peptide in CFA, or CFA alone. However, this adjuvant-mediated protection could be avoided by immunizing with TCR peptide in incomplete adjuvant (IFA). Clinical, but not histologic EAE was suppressed in rats given V beta 8 peptide in IFA, whereas control animals injected with V beta 14 peptide in IFA, or IFA alone developed severe clinical EAE. Anti-V beta 8 antibodies were present in the sera of all V beta 8-treated rats. These findings lend support to the hypothesis that autoimmune disease can be suppressed by inducing an immune response against the TCR-idiotope of autoreactive T cells.