Prevention and treatment of murine experimental allergic encephalomyelitis with T cell receptor V beta-specific antibodies

A natural anti-T-cell receptor monoclonal antibody protects against experimental autoimmune encephalomyelitis

The therapeutic potential of natural anti-T-cell receptor (TCR) antibodies is largely unknown. We investigated whether passive administration of C1-19, a novel natural anti-TCRVβ8 monoclonal antibody, could interfere with the development of EAE. Treatment with C1-19 prevented myelin basic protein (MBP)-induced EAE in Vβ8-sufficient B10.PL but not in Vβ8-deficient SJL mice. Furthermore, C1-19 reduced disease severity when administrated shortly after disease onset. These protective effects of C1-19 correlated with a Th2 bias of the cytokine response, in the absence of T-cell deletion or anergy. Together, these findings indicate that natural anti-TCR antibodies could function as therapeutic tools in autoimmune inflammatory diseases.

T cell targeted immunotherapy for autoimmune disease

Much emphasis has been placed on the so-called "biologics" in the treatment of immune disorders within the last few years. Here we discuss the expanding horizon of potential strategies for immunotherapies targeting T lymphocytes as key effectors and regulators of autoimmunity. We review emerging reagents in a variety of animal models and human disorders that may offer new therapeutic options in current or modified iterations.

Animal models of multiple sclerosis

Since its first description, experimental autoimmune encephalomyelitis, originally designated experimental allergic encephalitis (EAE), has been proposed as animal model to investigate pathogenetic hypotheses and test new treatments in the field of central nervous system inflammation and demyelination, which has become, in the last 30 years, the most popular animal model of multiple sclerosis (MS). This experimental disease can be obtained in all mammals tested so far, including nonhuman primates, allowing very advanced preclinical studies. Its appropriate use has led to the development of the most recent treatments approved for MS, also demonstrating its predictive value when properly handled. Some of the most exciting experiments validating the use of neural precursor cells (NPCs) as a potential therapeutic option in CNS inflammation have been performed in this model. We review here the most relevant immunological features of EAE in the different animal species and strains, and describe detailed protocols to obtain the three most common clinical courses of EAE in mice, with the hope to provide both cultural and practical basis for the use of this fascinating animal model.

Vaccines for multiple sclerosis: progress to date

Multiple sclerosis (MS) is an inflammatory demyelinating disease of the CNS, characterized pathologically by a perivascular infiltrate consisting predominantly of T cells and macrophages. Although its aetiology remains unknown, several lines of evidence support the hypothesis that autoimmune mechanisms play a major role in the development of the disease. Several widely used disease-modifying agents are approved for the treatment of MS. However, these agents are only partially effective and their ability to attenuate the more progressive phases of the disease is not clear at this time. Therefore, there is a need to develop improved treatment options for MS. This article reviews the role of several novel, selective vaccine strategies that are currently under investigation, including: (i) T-cell vaccination (TCV); (ii) T-cell receptor (TCR) peptide vaccination; (iii) DNA vaccination; and (iv) altered peptide ligand (APL) vaccination. The administration of attenuated autoreactive T cells induces regulatory networks to specifically suppress pathogenic T cells in MS, a strategy named TCV. The concept of TCV was based on the experience of vaccination against aetiological agents of infectious diseases in which individuals are purposely exposed to an attenuated microbial pathogen, which then instructs the immune system to recognize and neutralize it in its virulent form. In regard to TCV, attenuated, pathogenic T cells are similarly used to instruct the immune system to recognize and neutralize disease-inducing T cells. In experimental allergic encephalomyelitis (EAE), an animal model for MS, pathogenic T cells use a strikingly limited number of variable-region elements (V region) to form TCR specific for defined autoantigens. Thus, vaccination with peptides directed against these TCR structures may induce immunoregulatory mechanisms, thereby preventing EAE. However, unlike EAE, myelin-reactive T cells derived from MS patients utilize a broad range of different V regions, challenging the clinical utility of this approach. Subsequently, the demonstration that injection of plasmid DNA encoding a reporter gene into skeletal muscle results in expression of the encoded proteins, as well as in the induction of immune responses in animal models of autoimmunity, was explored as another strategy to re-establish self-tolerance. This approach has promise for the treatment of MS and, therefore, warrants further investigation. APLs are molecules in which the native encephalitogenic peptides are modified by substitution(s) of one or a few amino acids critical for contact with the TCR. Depending on the substitution(s) at the TCR contact residues of the cognate peptide, an APL can induce immune responses that can protect against or reverse EAE. However, the heterogeneity of the immune response in MS patients requires further study to determine which patients are most likely to benefit from APL therapy. Other potential approaches for vaccines in MS include vaccination against axonal growth inhibitors associated with myelin, use of dendritic cells pulsed with specific antigens, and active vaccination against proinflammatory cytokines. Overall, vaccines for MS represent promising approaches for the treatment of this devastating disease, as well as other autoimmune diseases.

Monoclonal antibody against T-cell receptor alphabeta induces self-tolerance in chronic experimental autoimmune encephalomyelitis

The therapeutic effect of monoclonal antibody (H57-597 MoAb) against T-cell receptor (TCR) alphabeta has been investigated on MOG(35-55)-induced experimental autoimmune encephalomyelitis (EAE), as a model system for T-cell-mediated chronic inflammation in the central nervous system (CNS). Short-term administration of the anti-TCR alphabeta immediately after immunization protected the mice from EAE. Furthermore, anti-TCR alphabeta treatment on an established disease restored the self-tolerance which led to a complete remission of EAE and a dramatic reduction of inflammatory cells in the CNS, while treatment with control antibody (hamster IgG) was ineffective. The remission was durable and not associated with disappearance of autoreactive T cells as measured by persistence of MOG-reactive T-cell proliferation in vitro. However, MOG-reactive T cells from anti-TCR-treated animals produced significantly lower amounts of inflammatory TNF-alpha and IFN-gamma. In addition, while a transient deletion of CD4(+) and CD8(+) T cells was observed, a population of T cells expressing CD3, NK1.1 and CD69 (NKT cells) were expanding. By transfer of spleen cells from anti-TCR MoAb-treated animals, we could show that the tolerogenic capacity can be transferred to untreated recipients with EAE. The data indicate therapeutic effect of anti-TCR alphabeta MoAb (H57-597), which represents a promising approach in treatment of T-cell-mediated autoimmune diseases.

Production, characterization, and immunogenicity of a soluble rat single chain T cell receptor specific for an encephalitogenic peptide

The encephalitogenic rat T cell clone C14 recognizes the myelin basic protein 69-89 peptide in the context of the RT1B major histocompatibility complex (MHC) class II molecule. Modeling of the C14 TCR molecule indicated that previously identified CDR3 motifs are likely to be central to interaction with MHC class II-presented peptide. Here we report the cloning and expression of C14-derived single chain TCR (scTCR) molecules in an Escherichia coli expression system. The recombinant molecule consists of the Valpha2 domain connected to the Vbeta8.2 domain via a 15-residue linker. Soluble C14 scTCR was purified using conventional chromatography techniques and refolded by a rapid dilution procedure. C14 scTCR was able to bind soluble rat MHC class II molecules bearing covalently coupled Gp-BP-(69-89) peptide, as analyzed using surface plasmon resonance. Immune recognition of the C14 scTCR protein as an antigen revealed that limited regions of the TCR may be more likely to induce responsiveness.

TCR usage and cytokine expression in peripheral blood and BAL T cells

T cells are thought to play an important regulatory role in atopic asthma. We hypothesized that human blood and BAL T cell subsets bearing various TCR-Vbeta genes might show selective differences in their cytokine profile. Peripheral blood (PB) and bronchoalveolar lavage (BAL) T cells from seven atopic asthmatic and six non-atopic non-asthmatic subjects were stimulated with PMA and ionomycin in the presence of monensin and analysed for TCR-Vbeta expression and production of cytokines at the single cell level. The percentage of IFN-gamma- and IL-2-producing BAL T cells was elevated compared with PB T cells from both the asthmatic subjects and the non-atopic, non-asthmatic controls. A small percentage of PB and BAL T cells produced IL-4 and IL-5, in asthmatic and normal subjects. In peripheral blood, the percentage of T cells expressing each cytokine was similar in the various TCR-Vbeta subsets and in total CD3+ T cells in all normal and six of seven asthmatic subjects. However, there was a substantial degree of heterogeneity in the cytokine profile of BAL TCR-Vbeta subsets compared with the total CD3+ T cells. This was more obvious in the asthmatic subjects with a reduction in the percentage of IFN-gamma- and IL-2-expressing T cells (five of seven asthmatic subjects) and an increase in the percentage of IL-4- and IL-5-expressing T cells (two of seven asthmatic subjects). These data confirm previous findings of an elevated proportion of IFN-gamma- and IL-2-producing BAL T cells while only a small proportion of PB and BAL T cells produce IL-4 and IL-5. Moreover, subsets of BAL T cells, defined by their TCR-Vbeta usage, may differ in their cytokine profile compared with the total CD3+ T cells, implying that T cells expressing different Vbeta elements may play different roles in regulating the airway inflammation in asthma.

Both B and gammadelta TCR(+) lymphocytes regulate alphabeta TCR(+) lymphocytes involved in superantigen specific responses

Endogenous superantigens (SAg) presented by MHC class II IA molecules induce slow-evolving negative selection of alpha beta T cells. The role of both B and gamma delta T cells on the regulation of these SAg-specific alpha beta T cell responses was addressed in IA(b+)IE(b-) C57BL/6 mice bearing genetically induced B cell and gamma delta T cell deficiencies. B lymphocytes were required in the negative selection of Vbeta5(+)/Vbeta12(+) CD4(+) T cells. In contrast, gamma delta T cells positively stimulated the utilization of the same SAg-responsive alpha beta T cell subsets. These differences started in mature CD4(+) thymocytes and extended to naive T cell pools for B cell negative selection, and up to memory T cells for gamma deltaT cell influences. The levels of SAg-responsive T cells did not vary between C57BL/6 and double deficient (B cell and gamma delta T cell-deficient) congenic mice, implying that both B and gamma delta T cells acted through independent mechanisms.

Characterization of a novel H2A(-)E+ transgenic model susceptible to heterologous but not self thyroglobulin in autoimmune thyroiditis: thyroiditis transfer with Vbeta8+ T cells

Recently we reported on a novel H2E transgenic, IA-negative model of experimental autoimmune thyroiditis (EAT) that excludes reactivity to self in its susceptibility pattern to heterologous thyroglobulin (Tg). In conventional, susceptible mouse strains, EAT is inducible with both homologous and heterologous Tg; e.g., human (h)Tg shares conserved thyroiditogenic epitopes with mouse (m)Tg. However, when an H2Ea(k) transgene is introduced into class II-negative B10.Ab(0) mice, which express neither surface IA (mutant Abeta-chain) nor surface IE (nonfunctional Ea gene), the resultant H2E(b) molecules are permissive for EAT induction by hTg, but not self mTg. Also, the hTg-primed cells do not cross-react with mTg. To explore this unique capacity of E+B10.Ab(0) mice to distinguish self from nonself Tg, we have developed T cell lines to examine the T cell receptor repertoire and observed a consistent Vbeta8+ component after repeated hTg stimulation. Enrichment and activation of Vbeta8+ T cells by either superantigen staphylococcal entertoxin B or anti-Vbeta8 in vitro enabled thyroiditis transfer to untreated A-E+ recipients, similar to hTg activation. Vbeta8+ T cells isolated by FACS from hTg-immunized mice also proliferated to hTg in vitro. These studies support the contribution of Vbeta8 genes to the pathogenicity of hTg in this H2A-E+ transgenic model.

Flexibility of TCR repertoire and permissiveness of HLA-DR3 molecules in experimental autoimmune thyroiditis in nonobese diabetic mice

Experimental autoimmune thyroiditis (EAT) is inducible in genetically susceptible mice by immunization with mouse thyroglobulin (mTg). With susceptibility linked to MHC class II, EAT is useful in studying human leukocyte antigen (HLA) associations with Hashimoto's thyroiditis. In non-obese diabetic (NOD) mice, approximately 10% thyroiditis incidence occurs with aging. This potential was exploited to examine the T cell repertoire and HLA association in EAT. Similar to B10.K-Vbeta(c)mice with TCRBV genes reduced by approximately 70%, mTg-immunized NOD-Vbeta(c)mice developed thyroiditis comparable to controls, indicating plasticity of the TCR repertoire for pathogenic epitopes. HLA association was evaluated by introducing HLA-DRA/DRB1*0301 (DR3) transgene into class II-negative NOD mice (Ab(0)/NOD). Previously, this HLA-DR3 transgene rendered EAT-resistant B10.M and Ab(0)mice susceptible to both mTg- and hTg-induced EAT. These results are now confirmed. mTg-induced thyroiditis in DR3+ Ab(0)/NOD mice was comparable to that in NOD and DR3- NOD mice, and the proliferative response was stronger. By comparison, NOD mice were only moderately susceptible to hTg-induced EAT. However, thyroiditis was more severe in DR3+ Ab(0)/NOD than in DR3- NOD mice, with no difference in proliferative response to hTg harbouring heterologous epitopes. The confirmed permissiveness of HLA-DR3 molecules on an NOD background for EAT induction by both mTg and hTg supports the importance of this class II gene implicated in some patient studies.

T lymphocytes promote the development of bone marrow-derived APC in the central nervous system

Certain cells within the CNS, microglial cells and perivascular macrophages, develop from hemopoietic myelomonocytic lineage progenitors in the bone marrow (BM). Such BM-derived cells function as CNS APC during the development of T cell-mediated paralytic inflammation in diseases such as experimental autoimmune encephalomyelitis and multiple sclerosis. We used a novel, interspecies, rat-into-mouse T cell and/or BM cell-transfer method to examine the development and function of BM-derived APC in the CNS. Activated rat T cells, specific for either myelin or nonmyelin Ag, entered the SCID mouse CNS within 3-5 days of cell transfer and caused an accelerated recruitment of BM-derived APC into the CNS. Rat APC in the mouse CNS developed from transferred rat BM within an 8-day period and were entirely sufficient for induction of CNS inflammation and paralysis mediated by myelin-specific rat T cells. The results demonstrate that T cells modulate the development of BM-derived CNS APC in an Ag-independent fashion. This previously unrecognized regulatory pathway, governing the presence of functional APC in the CNS, may be relevant to pathogenesis in experimental autoimmune encephalomyelitis, multiple sclerosis, and/or other CNS diseases involving myelomonocytic lineage cells.

Amelioration of experimental autoimmune uveoretinitis by pretreatment with a pathogenic peptide in liposome and anti-CD40 ligand monoclonal antibody

We have defined a peptide K2 (ADKDVVVLTSSRTGGV) that corresponds to residues 201-216 of bovine interphotoreceptor retinoid-binding protein and induces experimental autoimmune uveoretinitis (EAU)4 in H-2Ak-carrying mice (H-2Ak mice). In this study, we attempted to ameliorate EAU in the H-2Ak mice without nonspecific suppression of T cell responses. Preceding s.c. administration of liposomes including K2 (liposomal K2) specifically inhibited subsequent generation of T cell response to K2. The same result was obtained with a combination of OVA323-339 peptide and the OVA-specific TCR-transgenic T cells. It was suggested that the inhibition was mainly attributed to peripheral anergy induction of T cells specific for the peptide Ag, although specific cell death might also be involved in the inhibition. Pretreatment with liposomal K2 also considerably abolished IFN-gamma production but not IL-4 production. The specific inhibitory effect of the pretreatment with liposomal peptide was augmented by a simultaneous administration of anti-CD40 ligand (anti-CD40L) mAb. Moreover, it was shown that the pretreatment with liposomal K2 reduced both the incidence and severity of the subsequent K2-induced EAU, and the simultaneous administration of anti-CD40L mAb augmented this preventive effect by liposomal K2. Our findings demonstrate that the s.c. administration of liposomal pathogenic peptide and anti-CD40L mAb can be applied to preventing autoimmune diseases without detrimental nonspecific suppression of T cell responses.

Treatment of experimental autoimmune encephalomyelitis with adenylate deaminase from Penicillium lanoso-viride

The effect of intramuscularly administered immunomodulator, adenylate deaminase (E.C. 3.5.4.6), from Penicillium lanoso-viride on the clinical score of acute experimental autoimmune encephalomyelitis (EAE), a T cell-mediated autoimmune disease, was examined by inoculation of guinea pigs with rabbit brain and spinal cord homogenate (encephalitogen) and complete Freund's adjuvant. Adenylate deaminase (ADA) was effective in delaying the onset of clinical disease. ADA inhibited the severity of EAE. There was a significant decrease in clinical signs. A decrease in the number of morbid and dead animals was observed. Of ADA treated animals, 50-80% developed no clinical manifestations of EAE. The optimal version of treatment was a single preventive injection of ADA 1 day before the sensitization and then every second day after immunization for 20 days. ADA treatment of immunized animals diminished the activity of 2', 3'-cyclic nucleotide 3'-phosphodiesterase in the cerebrospinal fluid, as well the amount of complement fixing antiencephalitogenic antibodies in the blood serum. The mechanism of ADA cerebroprotective action is discussed. Significant skin-allergic cross-reaction of delayed-type hypersensitivity between ADA and encephalitogen was observed.

Inhibition of experimental allergic encephalomyelitis with an antibody that recognizes a novel antigen expressed on lymphocytes, endothelial cells, and microglia

Experimental allergic encephalomyelitis (EAE) is a frequently employed animal model of the human disease multiple sclerosis. EAE can be induced by adoptive transfer of CD4+ T cells that are specific for central nervous system (CNS) antigens, typically myelin proteins. Although the pathogenic mechanism or mechanisms responsible for the clinical signs and histological changes in EAE and multiple sclerosis are not fully defined, the entry of T lymphocytes and antigen recognition within the CNS are required. The present study describes the participation of a novel cell surface molecule with properties suggesting a role in cell-cell adhesion or co-stimulation, or both, in the development of EAE in the rat. The molecule is defined by the unique monoclonal antibody (mAb) TLD-4A2. The TLD-4A2 antigen is present on resting and activated T lymphocytes, activated CNS endothelial cells, and microglia. The antigen is normally distributed in many tissues including lymph node, thymus, and spleen, as well as in the inflamed CNS. Both its pattern of tissue distribution and immunoprecipitation and immunoblotting studies suggest that the TLD-4A2 antigen is a novel molecule. Treatment of rats with the purified 4A2 mAb resulted in the inhibition of the clinical signs of EAE and also decreased the number T cells and macrophages accumulating in the CNS parenchyma. TLD-4A2 antibody did not seem to directly interfere with T cell viability in vivo, as demonstrated by the ability to recover and stimulate CD4+ encephalitogenic T cells from cervical lymph nodes of 4A2-treated animals. In vitro, the antibody partially blocked T cell proliferation assays. These data suggest that the TLD-4A2 mAb recognizes a novel molecule expressed on lymphocytes, endothelial cells, and macrophages that may play a role in hematogenous cell traffic and the initiation of CNS inflammation.

Tolerance and autoimmunity in TCR transgenic mice specific for myelin basic protein

T-cell receptor (TCR) transgenic mice provide the ability to follow the maturation and fate of T cells specific for self-antigens in vivo. This technology represents a major breakthrough in the study of autoimmune diseases in which specific antigens have been implicated. Proteins expressed within the central nervous system are believed to be important autoantigens in multiple sclerosis. TCR transgenic models specific for myelin basic protein (MBP) allowed us to assess the role of tolerance in providing protection from T cells with this specificity. Our studies demonstrate that T cells specific for the immunodominant epitope of MBP do not undergo tolerance in vivo and that TCR transgenic mice are susceptible to spontaneous autoimmune disease. The susceptibility to spontaneous disease is dependent on exposure to microbial antigens. MBP TCR transgenic models expressing TCRs specific for the same epitope of MBP but utilizing different V alpha genes exhibit differing susceptibilities to spontaneous disease. These data support the idea that genetic and environmental differences play a role in susceptibility to autoimmunity. MBP TCR transgenic models are playing an important role in defining mechanisms by which infectious agents trigger autoimmune disease as well as defining mechanisms by which tolerance is induced to distinct epitopes within self-antigens.

Vbeta8+ T lymphocytes are essential in the regulation of airway hyperresponsiveness and bronchoalveolar eosinophilia but not in allergen-specific IgE in a murine model of allergic asthma

BACKGROUND

There is increasing evidence that in allergic asthma the inflammatory process is regulated by T lymphocytes. In BALB/c mice the majority of ovalbumin responsive T lymphocytes express the Vbeta8.1+ and Vbeta8.2+ T-cell receptor.

OBJECTIVE

We analysed the contribution of Vbeta8+ T lymphocytes during the sensitization and challenge phase in the regulation of antigen-specific IgE, airway hyperresponsiveness and cellular infiltration in the airways in a murine model of allergic asthma.

METHODS

Mice strains genetically lacking (SJL/J and SJA/9) and expressing (BALB/c) the Vbeta8+ T cell receptor were used. In addition, prior to the sensitization and prior to the challenge BALB/c mice were treated with antibodies to Vbeta8. Mice were sensitized with ovalbumin, followed by repeated challenge with ovalbumin or saline aerosols.

RESULTS

In ovalbumin challenged BALB/c mice treated with control antibody a significant increase in eosinophils in the bronchoalveolar lavage, airway hyperresponsiveness and increased serum levels of ovalbumin-specific IgE were observed compared to control mice. Treatment of BALB/c mice with antibodies to Vbeta8 prior to the sensitization or prior to the challenge period completely inhibited the ovalbumin induced infiltration of eosinophils and airway hyperresponsiveness, while ovalbumin-specific IgE was slightly decreased. In SJA/9 and SJL/J mice ovalbumin challenge did not induce eosinophilic infiltration and airway hyperresponsiveness. In SJL/J mice ovalbumin challenge induced an upregulation of ovalbumin-specific IgE, however, in SJA/9 mice no upregulation was observed.

CONCLUSION

It is demonstrated that Vbeta8+ T lymphocytes are essential for infiltration of eosinophils in the airways and development of airway hyperresponsiveness in a murine model of allergic asthma. In contrast, although Vbeta8+ T lymphocytes seem to be important for the extent of IgE levels, no essential role for Vbeta8+ T lymphocytes in the induction of antigen-specific IgE was observed.

Successful prevention of retrocochlear hearing loss in murine experimental allergic encephalomyelitis with T cell receptor Vbeta8-specific antibody

Experimental allergic encephalomyelitis is an animal model of a T cell-mediated autoimmune disease -- for example, multiple sclerosis. We demonstrated that mice with experimental allergic encephalomyelitis developed retrocochlear hearing loss, and that the lesion of the auditory pathway might be related to T cell receptor Vbeta8-expressing T cells. To investigate whether anti-Vbeta8 antibody could prevent hearing loss, we carried out brain stem auditory evoked potential testing, histologic examinations, and flow cytometry in antibody-treated and control myelin basic protein-immunized B10.PL mice. The antibody was administered just before immunization of myelin basic protein. The disease incidence and severity were significantly reduced in the mice injected with the antibody. The results of brain stem auditory evoked potential testing, histologic examinations, and flow cytometry indicated that the depletion of Vbeta8-expressing T cells brings the prevention of hearing loss, as well as prevention of other neurologic deficits. The development of T cell receptor-specific antibody therapy might help treat retrocochlear hearing loss in multiple sclerosis.

T cells with similar T-cell receptor beta-chain complementarity-determining region 3 motifs infiltrate inflammatory lesions of synthetic peptides inducing rat autoimmune myocarditis

Experimental autoimmune myocarditis (EAM) resembles the giant cell myocarditis seen in humans, and recurrent forms lead to dilated cardiomyopathy. EAM has been shown to be a T cell-mediated autoimmune myocarditis. We have previously shown that cDNA encoding Vbeta complementarity-determining region (CDR) 3 from heart- and pericardial space-infiltrating T cells in EAM induced by rod cardiac myosin contains more restricted sequences than that from normal spleen T cells. Recently, it has become apparent that several epitopes of EAM exist in rod cardiac myosin; therefore, T cells infiltrating into lesions may recognize certain epitopes in EAM induced by rod cardiac myosin. In this study, we examined heart- and pericardial space-infiltrating T-cell clonotypes in EAM induced by synthetic peptides of cardiac myosin. EAM was produced by immunization with synthetic peptides corresponding to N-terminally acetylated amino acids 1539 to 1555 of rat cardiac myosin alpha heavy chain. Five of 12 rats receiving synthetic peptides developed macroscopic signs of myocarditis. To examine T-cell receptor (TCR) Vbeta expression and CDR3 of the TCR beta chain of lesion-infiltrating T cells in EAM, total RNA was isolated from heart, pericardial effusion, spleen, lymph node, and peripheral blood. TCR Vbeta expression of the T cells infiltrating the lesions revealed a predominance of Vbeta4. On the basis of single-strand conformation polymorphism analysis for CDR3 of the TCR Vbeta4 chain, heart- and pericardial space-infiltrating T cells were considered to be oligoclonal, whereas spleen, lymph node, and peripheral blood in a rat with EAM and spleen in a native rat were considered to be polyclonal. In the same rat, clonotypes of heart-infiltrating T cells were almost the same as those of pericardial space-infiltrating T cells. Furthermore, on sequence analysis for CDR3 of the TCR Vbeta4 chain, the amino acid motifs were similar among T cells infiltrating into lesions of different EAM rats. In the present study, TCR beta chains of heart- and pericardial space-infiltrating T cells in EAM induced by synthesized peptide consisting of 17 amino acids were examined. Vbeta4+ T cells with similar Vbeta CDR3 motifs that infiltrate the heart and pericardial space may recognize the same epitope.

Anti-T-cell receptor therapy in murine experimental systemic lupus erythematosus

Experimental systemic lupus erythematosus (SLE), similar to that observed after immunization with the human anti-DNA mAb 16/6 Id+, could be induced in mice by injection of 16/6 Id specific T-cell lines. The above T-cell lines were exclusively CD4+ CD8- and the majority of cells expressed the Vbeta8 T-cell receptor (TCR) gene products. Furthermore, lymph node cells of mice immunized with the 16/6 Id were enriched with CD4+ Vbeta8+ T-cells. The TCR used by 16/6 Id-specific T-cells showed a limited homology in their CDR3 junctional regions. Nevertheless, mice injected with the anti-Vbeta8 mAb developed autoantibody titers that were not significantly different from those found in the non-treated, 16/6 Id-injected group.

Pathogenesis of neuroimmunologic diseases. Experimental models

Animal models of autoimmune diseases have greatly improved our current understanding of the pathogenesis of human autoimmunity and have provided the potential for therapies based on manipulation of the immune system. In our laboratory, we have investigated the immunopathogenesis of autoimmune diseases of the nervous system and muscle. We have developed immune-based approaches for the suppression of experimental autoimmune encephalomyelitis (EAE), a model for multiple sclerosis (MS), and experimental autoimmune neuritis (EAN), a model for the Guillain-Barré syndrome (GBS). These approaches included induction of peripheral tolerance, immunotoxin targeting of activated T cells, and cytokine manipulations. In addition, we identified the antigen and characterized immunopathologically an autoimmune inflammatory disease of skeletal muscle, experimental autoimmune myositis (EAM), a model for the human inflammatory muscle disease polymyositis.

Interaction of pigeon cytochrome c-(43-58) peptide analogs with either T cell antigen receptor or I-Ab molecule

We determined that a pigeon cytochrome c-derived peptide, p43-58, possesses two anchor residues, 46 and 54, for binding with the I-Ab molecule that are compatible to the position 1 (P1) and position 9 (P9) of the core region in the major histocompatibility complex (MHC) class II binding peptides, respectively. In the present study to analyze each binding site between P1 and P9 of p43-58 to either I-Ab or T cell antigen receptor (TCR), we investigated T cell responses to a series of peptides (P2K, P3K, P4K, P5K, P6K, P7K, and P8E) that sequentially substituted charged amino acid residues for the residues at P2 to P8 of p43-58. T cells from C57BL/10 (I-Ab) mice immunized with P4K or P6K did not mount appreciable proliferative responses to the immunogens, but those primed with other peptides (P2K, P3K, P5K, P7K, and P8E) showed substantial responses in an immunogen-specific manner. It was demonstrated by binding studies that P1 and P9 functioned as main anchors and P4 and P6 functioned as secondary anchors to I-Ab. Analyses of Vbeta usage of T cell lines specific for these analogs suggested that P8 interacts with the complementarity-determining region 1 (CDR1)/CDR2 of the TCR beta chain. Furthermore, sequencing of the TCR on T cell hybridomas specific for these analogs indicated that P5 interacts with the CDR3 of the TCR beta chain. The present findings are consistent with the three-dimensional structure of the trimolecular complex that has been reported for TCR/peptide/MHC class I molecules.

Longitudinal study of myelin basic protein-specific T-cell receptors during the course of multiple sclerosis

This study analyzed the stability of the myelin basic protein (MBP)-specific T-cell receptor (TCR) repertoire during the course of multiple sclerosis (MS) in three patients who were monitored for three years by gadolinium-enhanced magnetic resonance imaging. Bulk-culture T-cell lines (TCLs) were generated from 3-4 time points for each patient, including times of active and quiescent disease. TCR analysis of these TCLs indicated that both the V alpha and V beta usage was similar over time for each patient. Sequencing of TCRs demonstrated conserved complementarity-determining region 3 (CDR3) sequences within TCLs that expressed the same V alpha segment over time, although the J alpha usage was different for each TCR. This indicates that the population of MBP-reactive T-cells is changing during the course of MS, but that host and/or environmental factors may be selecting T-cells with particular MHC/peptide binding domains.

Tolerance induction and autoimmune encephalomyelitis amelioration after administration of myelin basic protein-derived peptide

Experimental autoimmune encephalomyelitis (EAE), a demyelinating disease of the central nervous system, is an animal model of paralyzing human disease, multiple sclerosis. EAE is readily induced by immunization with myelin basic protein (MBP) in mice transgenic for an alphabeta T cell receptor (TCR) that is specific for MBP. Subcutaneous injection of p17 (a peptide consisting of 17 NH2-terminal aminoacids of MBP) in complete Freund's adjuvant (CFA) causes paralysis. Induction of paralysis is inhibited by prior intraperitoneal injection of the same peptide in incomplete Freund's adjuvant (IFA). In addition, ongoing paralysis is ameliorated by subsequent intraperitoneal injection of p17 in IFA. Tolerance induction is equally efficient in Fas-deficient and IL-4-deficient TCR-transgenic mice, suggesting that neither activation-induced cell death nor differentiation into Th2 type cells plays a role in the tolerance induction. Tolerance induction by p17 seems to be based on reduction in the responsiveness of anti-MBP T cells, as documented by lower overall antigen-induced lymphokine production and proliferation, as well as diminished upregulation of early activation marker CD69 by tolerized T cells. We propose that continuous encounters of MBP-specific T cells with p17 play a critical role in the induction and maintenance of tolerance.

Induction of a heterogeneous TCR repertoire in (PL/JXSJL/J)F1 mice by myelin basic protein peptide Ac1-11 and its analog Ac1-11[4A]

Experimental autoimmune encephalomyelitis (EAE) serves as a rodent model of the autoimmune disease multiple sclerosis. In mice, EAE is induced by immunizing with spinal cord homogenate, components of the myelin sheath, such as myelin basic protein (MBP) or proteolipid protein (PLP), or peptides derived from these components. EAE can be induced in H-2u or (H-2u x H-2s)F1 mice with the N-terminal peptide of MBP, Ac1-11. Coimmunization with Ac1-11 and Ac1-11[4A], an analog in which lysine at position four is substituted with alanine, prevents EAE. The mechanism of inhibition has not been elucidated, but probably does not work through MHC blockade, T cell anergy or clonal elimination of encephalitogenic T cells. We have isolated T cell clones and hybridomas from (PL/J x SJL/J)F1 mice immunized with either Ac1-11 alone or Ac1-11 and Ac1-11[4A] and analysed these cells for differences in their T cell receptor repertoire and in vitro response. Although T cells elicited by coinjection of Ac1-11 and Ac1-11[4A] expressed TCR that used V alpha and Vbeta gene elements similar to those elicited by Ac1-11 alone, they differed in the sequences of the junctional region of the alpha chain. Most of these T cells also responded less well to Ac1-11 in vitro, suggesting that coinjection of Ac1-11 and Ac1-11[4A] preferentially activates T cells bearing TCR of different affinity for Ac1-11 bound to I-A(u), and which may therefore be less encephalitogenic. Furthermore, our results show that a more diverse repertoire of V alpha and Vbeta genes are elicited by Ac1-11 in (PL/J x SJL/J)F1 mice compared to PL/J and B10.PL mice, providing further evidence that a restricted TCR repertoire is not required for the development of autoimmune disease.

The characterization of testicular cell (TC)-specific T-cell clones induced by intratesticular Listeria monocytogenes infection: TC-specific T cells with atypical cytokine profile transfer orchitis

A unilateral infection of Listeria monocytogenes into the testis of mice induces not only Listeria-specific T cells but also autoreactive T cells that can transfer experimental autoimmune orchitis (EAO) into naive mice. To investigate the characteristics of the autoreactive T cells, we established six testicular cell (TC)-specific T-cell clones from the spleen of the intratesticularly infected mice. All the clones expressed CD4 and T-cell receptor (TCR) alpha beta, and four of the six clones expressed V beta 8. They showed proliferative response to TC in the presence of syngeneic spleen antigen-presenting cells, but did not cross-react to Listeria antigen (Ag). They produced interferon-gamma (IFN-gamma) when stimulated with TC, but interleukin-2 (IL-2), IL-4 and IL-10 were undetectable. IL-2 production was not detected even when they were restimulated with TC after a 10-day resting culture without Ag and IL-2, although they proliferated in the restimulation culture. Even in the presence of anti-IL-2 mAb, the TC-specific T-cell clones showed proliferative response against TC. The observations indicate that the TC-specific IFN-gamma-producing T cells proliferate in the absence of autocrine. Both intravenous and intratesticular injection of these clones transferred EAO in syngeneic naive mice. These results suggest that L. monocytogenes infection in the testis induces autoreactive orchitogenic CD4+ T cells without cross-reactivity to bacterial Ag. Furthermore, these data demonstrate that CD4+ T cells with an atypical cytokine profile can efficiently cause EAO.

Predominant T-cell receptor Vbeta usage of intraepithelial lymphocytes during the immune response to enteric reovirus infection

Previous studies have found that intraepithelial lymphocytes (IEL) contain virus-specific cytotoxic T lymphocytes (CTL) that increase dramatically during the course of virus infection. In the present study, the T-cell receptor (TCR) V beta pattern used by IEL against reovirus enteric infection was investigated both in conventional and in germfree mice. IEL were isolated by a modified rapid method, and their expression of 13 TCR V betas was examined by flow cytometric analysis. The virus-specific CTL activity of each TCR V beta subset was assessed by subtraction with coated Dyna beads by a nonradioactive assay. There was a preferential perturbation of TCR V betas following virus challenge, including increases in cells expressing V beta7, -12, -14, and -17 in conventional mice and V beta2, -12, and -17 in germfree mice. In conventionally reared mice, IEL maintained and restimulated in culture had a preferential use of TCR V beta9, -12, and -17. TCR V beta2 and -17 subfamilies were found amplified in all conditions. Furthermore, TCR V beta12 and -17 accounted for 37 and 77% of the virus-specific CTL activity, respectively, after in vitro restimulation. This study provides evidence that virus-specific CTL activity may be due to the oligoclonal expansion of TCR V beta subfamilies in IEL. Our findings suggest that in vivo infection selectively presents few T-cell epitopes and that the correct identification of these T-cell epitopes would increase the likelihood of success when designing subunit vaccines.

Protection from experimental autoimmune encephalomyelitis (EAE): non-depleting anti-CD4 mAb treatment induces peripheral T-cell tolerance to MBP in PL/J mice

Following pre-treatment with a non-depleting anti-CD4 mAb (H129.19) that produces long-lasting receptor saturation, PL/J mice were fully protected from experimental auto-immune encephalomyelitis (EAE) induced by injection of myelin basic protein (MBP). These mice did not develop EAE following MBP re-challenge 5-10 weeks later when the CD4+ cells were no longer coated by the mAb and their lymph node cells were specifically unresponsive to MBP stimulation in vitro. Moreover, superantigen staphylococcal enterotoxin B (SEB) inoculation, which re-induces EAE in MBP immunized mice, failed to activate encephalitogenic T-cells in anti-CD4 + MBP treated mice, even after MBP re-challenge, indicating that tolerance in the peripheral T-cell compartment was achieved. However, MBP re-challenge 16 weeks later, but not SEB, produced an acute episode of EAE in these mice, while it failed to induce disease in a parallel group of adult thymectomized mice. These results indicate that no memory of the first priming exists at this time and that new MBP-specific T-cell precursors are peripheralized and produce EAE after MBP recognition.

Suppression of experimental autoimmune encephalomyelitis (EAE) by intraperitoneal administration of soluble myelin antigens in Wistar rats

Intraperitoneal (i.p.) treatment of Wistar rats with bovine myelin (BM) or myelin basic protein (MBP) previously to immunization with BM-CFA showed a diminished incidence and severity of experimental autoimmune encephalomyelitis (EAE) (2/13 and 0/7, respectively) when compared with rats immunized with BM-CFA (11/17) or i.p. treated with ovalbumin (2/4). Concomitantly, animals treated with BM or MBP exhibited a marked reduction of proliferative response to MBP which was highly positive when spleen mononuclear cells from nontreated and ovalbumin treated animals were assayed. Rats that were treated with MBP before immunization produce IgA, IgM, total IgG and subclasses of IgG, IgG2a, IgG2b, IgG2c specific for MBP in similar levels than those observed in nontreated immunized animals. However, a higher incidence and level of IgG1 was observed in MBP treated rats, meanwhile rats i.p. treated with total BM showed a highly reduced humoral response. The herein presented results show that i.p. treatment with low amounts of soluble forms of myelin antigens markedly reduced the clinical symptoms of the disease, the histological alterations, the cellular proliferative response to MBP, and produced changes in the autoimmune humoral response.

Induction of experimental autoimmune encephalomyelitis by CD4+ T cells specific for an astrocyte protein, S100 beta

S100 beta protein is a calcium binding protein that is not only expressed by astrocytes in the CNS, but also in many other tissues including the eye, thymus, spleen and lymph nodes. Despite this tissue distribution, which was expected to induce a firm state of self-tolerance to S100 beta, the Lewis rat mounts a strong T cell response to this autoantigen. The pathogenicity of this T cell response was demonstrated by the adoptive transfer of S100 beta-specific T cells which induced an inflammatory response in the CNS and eye of naive syngeneic recipients. The distribution of lesions in this novel model of EAE resembles that seen in some patients with MS, suggesting that the initial autoimmune insult in MS may be directed against a non-myelin antigen co-expressed in the CNS and extra-neural tissues.

Restricted T cell receptor repertoire for acetylcholine receptor in murine myasthenia gravis

Immunization of C57BL/6 mice with AChR provokes symptoms similar to those seen in the disease myasthenia gravis. To elucidate the structural requirements for T cell recognition of AChR and to identify TcR features which might provide targets for immunotherapy, a panel of T cell hybridomas was generated after immunization of mice with the immunodominant peptide of the AChR alpha chain. The TcR genes expressed by these hybridomas were sequenced. TcR-V beta 6 was preferentially employed, but other V beta genes were also observed. A conserved acidic residue was present in all CDR3 regions, regardless of the V beta. The TcR-V alpha repertoire was somewhat skewed with three V alpha families accounting for 82% of the sequences. The utilization of multiple T cell receptor V beta genes may contribute to the inability to inhibit EAMG by elimination of V beta 6+ T cells.

Treatment of relapsing autoimmune encephalomyelitis with T cell receptor V beta-specific antibodies when proteolipid protein is the autoantigen

Monoclonal antibodies (mAbs) directed against the V beta chain of the T cell receptor (TCR) of pathogenic T cells have been used to treat acute murine experimental autoimmune encephalomyelitis (EAE) induced by myelin basic protein (BP). We evaluated anti-V beta mAb for the treatment of relapsing EAE (R-EAE) induced in SJL/J mice by the myelin proteolipid protein (PLP) peptide 139-151. Spinal cord mononuclear cells isolated from mice immunized for R-EAE with PLP 139-151 were shown to express a predominance of V beta 2 and V beta 17 during acute and relapsing disease. T cell lines specific for PLP 139-151 were magnetically sorted to express 80-90% V beta 2. These V beta 2-enriched lines induced typical relapsing demyelinating EAE in naive recipient mice. SJL/J mice with R-EAE induced by a PLP 139-151-specific T cell line expressing 88% V beta 2 were treated with anti-V beta 2 mAb. Anti-V beta 2 mAb markedly reduced clinical and histological disease severity when given at the time of cell transfer or when given at clinical disease onset. In contrast, anti-V beta mAbs showed only a mild clinical effect on R-EAE induced by immunization with PLP 139-151 or R-EAE transferred by a PLP 139-151-specific T cell line expressing multiple V beta s. A cocktail of mAbs directed against V beta 2, V beta 4, and V beta 17 significantly reduced the numbers of spinal cord T cells expressing these V beta s during acute EAE but had little effect on disease course, suggesting that pathogenic T cells expressing other V beta s were producing disease. These findings may have implications for the treatment of multiple sclerosis with V beta-selective therapy.

Vaccination with peptides from MHC class II beta chain hypervariable region causes allele-specific suppression of EAE

In our earlier studies we showed that successful immunotherapy of EAE in SJL/J mice can be achieved either by the use of antibodies to MHC class II antigens or by vaccination with synthetic peptide analogs of the beta chain of MHC class II molecules. We proposed that inhibition of EAE following vaccination with synthetic peptides derived from the beta chain of mouse I-A, was in part due to the generation of auto-anti-MHC class II antibodies that interfered with T cell sensitization. In our present study we show that suppression of EAE following vaccination results in poor sensitization of MBP reactive T cells, and that the lack of immune response is allele-specific. In F1(SJL(I-AS) x Balb/cI-Ad) mice, in which susceptibility to EAE is linked closely to the I-AS allele, vaccination with peptides from beta chain of I-AS results in inhibition of proliferative response to MBP and prevents the development of EAE. Vaccination with peptide from the beta chain of I-Ad did not affect either the development of immune response to MBP or the induction of EAE, indicating allele-specific suppression. Since global immunosuppression is not induced by vaccination with I-A peptides, we propose that this strategy can be extended to human autoimmune diseases wherein a clear association between certain MHC class II alleles and autoimmune disease is evident.

New therapeutic avenues in autoimmunity

During the last decade, much progress has been made in the understanding of processes that lead to autoimmunity. Cellular interactions mediated through cytokines and adhesion molecules were found to play a major role in the genesis of autoimmune conditions. During this period, we learned to recruit monoclonal antibodies to manipulate these delicate processes and to divert their outcome to a path we control better. Our comprehension of IVIG (intravenous immunoglobulin therapy) has broadened, and new indications for the implementation of this promising therapy have been pursued. In this review, we shed light on new therapeutic modalities that have been published since our previous report and discuss new data concerning the old modalities.

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

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

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Derivation of T-cell receptor alpha-chain double expresser lines from normal murine mature T cells

Because the T-cell receptor (TCR) alpha-chain locus is known to lack allelic exclusion of rearrangements, and as a recent report revealed the existence of alpha-chain double expressers among normal human peripheral blood lymphocytes (PBL), the possible existence of TCR alpha-chain double expressers among mature murine T cells was examined. Although two-colour staining analysis of normal T-cell populations did not immediately reveal recognizable clusters of V alpha double expressers, alternative in vitro stimulations of normal murine T cells with antibodies to two different TCR V alpha chains reproducibly induced TCR alpha-chain double-expresser lines. TCR complexes with different alpha-chains on such T cells were both shown to be functional. The cell lines were heterogeneous with respect to V beta usage and the ratio of the expressed amounts of the two alpha-chains on the surface. The ratio of the two expressed alpha-chains was found to be very stable over a long period of time. These results are consistent with the earlier report on alpha-chain double expressers among human T cells and also show normal occurrence of TCR alpha-chain double expressers in murine T-cell populations.

Experimental immunotherapies for multiple sclerosis

Multiple sclerosis (MS) is a chronic demyelinating disease affecting the central nervous system (CNS) principally in young adults. Although its etiology is as yet unknown current evidence suggests that tissue damage is mediated by autoimmune T cells. The examination of an experimental animal model for MS, experimental allergic encephalomyelitis (EAE), has demonstrated that myelin basic protein (MBP)- or proteolipid protein (PLP)-specific T cells mediate the destruction of CNS myelin. In recent years, elegant studies in EAE have shown that encephalitogenic T cells recognize short peptides of MBP or PLP in the context of MHC/HLA-class II molecules, express a restricted number of T cell receptor (TCR) molecules and secrete interferon-gamma and tumor necrosis factor-alpha/beta. Understanding the pathogenetic steps in lesion development at the molecular level led to highly specific immunotherapies for EAE targeting each individual molecule. It has been the hope of many investigators that immunological events resembling those in EAE can be found in patients with MS and that the specific immunotherapies effective in EAE could also be applied to MS. However, to date, the evidence for a unique immunological abnormality in MS is not strong. Although MBP- and PLP-specific T cells with properties similar to those that are encephalitogenic in animals can be isolated from patients, they are not specific for MS and occur with similar frequency in controls. In addition, the variability in specificity and TCR usage has raised questions regarding the relevance of these cells in patients. The importance of the T cell responses to myelin antigens in MS may not be established until the effects of abrogating their activity through specific therapies targeting the trimolecular complex (TMC) have been demonstrated. Consequently, attention has begun to focus on modifying the biology of the MS lesion rather than targeting the initiating event at the level of the TMC, and the success of this approach is reflected by the effect of interferon-beta on lesion development in MS. The recent approval for the use of interferon-beta for the treatment of relapsing-remitting MS has raised great interest in examining novel strategies for immunotherapies in MS. The basic concepts as well as the current candidates for such new immunotherapies will be outlined in this short review.

Multiple sclerosis

Multiple sclerosis is a chronic disease that begins in late adolescence or adulthood. It is highly variable in its expression and severity. It is believed to be autoimmune in nature. The cause is unknown; both genetic and environmental factors have been implicated in the pathogenesis. MS generally presents with the acute or subacute onset of neurologic abnormalities that may wax and wane over many years. Diagnosis is generally made by means of observation of the clinical course in conjunction with a neurologic examination and laboratory tests. These tests may include magnetic resonance imaging of the head and spine, lumbar puncture, and evoked potentials. Treatment is based on general supportive care, the use of corticosteroids for relapses, and symptomatic management of ongoing problems. The frequency of relapses can be reduced with interferon-beta (Betaseron). Copolymer 1 and interferon-beta la are being evaluated by the U.S. Food and Drug Administration for approval for use for reduction in the frequency of relapses in relapsing-remitting MS. Treatment of chronic progression is often attempted with immunosuppressive agents such as corticosteroids, azathioprine, and cyclophosphamide. Use of other agents is being investigated.

Short-term administration of selected anti-T-cell receptor V beta chain specific MoAb reduces sialadenitis in MRL/lpr mice

Sialadenitis develops spontaneously in MRL/Mp mice bearing a lymphoproliferative gene, lpr (MRL/Mp-lpr/lpr). Based on recent observations of an oligoclonal expansion of T-cell receptor (TCR) expressing V beta chain families (V beta 4, V beta 8.1,2, V beta 10b) in salivary glands of these mice we have initiated selective antibody therapy. Treatment with monoclonal antibodies (MoAb) specific for T cells expressing a mixture of TCR V beta 4, V beta 8.1,2 and V beta 10b was applied to MRL/lpr mice before and after the spontaneous development of sialadenitis. The in vivo treatment with V beta 4, V beta 8.1,2 and V beta 10b MoAb did not prevent the development of sialadenitis. However, in animals with established sialadenitis, treatment with the MoAb significantly decreased the inflammation compared with the control groups. Immunohistochemical staining of cell phenotypes demonstrated a change in the ratio of CD4/CD8 in the animals with established sialadenitis. Altogether, these findings illustrate that it is possible to modulate sialadenitis and infiltrate cell phenotypes in vivo in MRL/lpr mice with specific anti-TCR V beta MoAb treatment.

Mechanisms by which the I-ABM12 mutation influences susceptibility to experimental myasthenia gravis: a study in homozygous and heterozygous mice

The I-Abm12 mutation in C57B1/6 (B6) mice yields the B6.C-H-2bm12 (bm12) strain, which is resistant to Experimental Myasthenia Gravis (EMG) induced by immunization with Torpedo acetylcholine receptor (TAChR), while the parental B6 strain is highly susceptible to EMG. CD4+ cells from bm12 mice immunized with TAChR do not recognize three sequence regions of the TAChR alpha subunit which dominate the CD4+ cell sensitization in B6 mice. We immunized with TAChR bm12, B6 and (bm12 x B6)F1 mice. B6 and F1 mice developed EMG with comparable frequency. Their CD4+ cells recognized the same TAChR alpha subunit peptide sequences (T alpha 150-169, T alpha 181-200 and T alpha 360-378). CD4+ cells from TAChR-sensitized F1 mice were challenged with TAChR and alpha subunit epitope peptides, using F1, B6 or bm12 APC. B6 and F1 APC presented all these Ag efficiently, while bm12 APC presented TAChR and peptide T alpha 150-169 poorly and erratically. Anti-TAChR and anti-alpha subunit epitope CD4+ lines propagated from F1 and B6 mice had similar TcR V beta usage. All lines but those specific for the sequence T alpha 150-169 had unrestricted V beta usage. Anti-T alpha 150-169 lines from both B6 and F1 mice had a strong preferential usage of V beta 6. Anti-T alpha 150-169 lines from F1 mice had also a slightly higher V beta 14 usage. B6, bm12 and F1 mice developed similar anti-TAChR Ab titres, and had Ab bound to muscle AChR in comparable amounts. Therefore EMG resistance of bm12 mice must be due to a subtle shift in the anti-AChR Ab repertoire, and absence of special Ab able to cause destruction and/or dysfunction of muscle AChR. This is probably related to the absence of CD4+ cells sensitized to epitopes within the sequence T alpha 150-160, consequent to the inability of the I-Abm12 molecule to present this sequence.

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

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