Autoantigen specific IL-2 activated CD4+CD25+T regulatory cells inhibit induction of experimental autoimmune neuritis.

Experimental autoimmune neuritis (EAN) induced by peripheral nerve myelin (PNM) is self-limiting and re-immunization with PNM does not re-activate disease. This study showed inhibition of EAN by CD4+CD25+T cells both from sensitized hosts or from naïve hosts after ex-vivo activation by PNM and rIL-2. Transfer of naïve CD4+CD25+T cells has no effect on EAN, nor did naïve CD4+CD25+T cells activated with rIL-2 and renal tubular antigen. Culture of naive CD4+CD25+Treg with rIL-2 and PNM induced mRNA for the IFN-gamma receptor. We showed naïve CD4+CD25+T cells activated by specific auto-antigen and rIL-2 produced more potent antigen-specific Treg that may have therapeutic potential.

Laquinimod in the treatment of relapsing remitting multiple sclerosis.

INTRODUCTION: Laquinimod is a new once-daily oral administrable agent, which is under investigation in a phase 3 clinical trial for relapsing remitting multiple sclerosis (RRMS) and in a phase 2 clinical trial for primary progressive MS (PPMS). AREAS COVERED: The pharmacokinetic, pharmacodynamic and the safety profiles of laquinimod are covered in this review. In preclinical studies, the ability to prevent both experimental autoimmune encephalomyelitis and experimental autoimmune neuritis has been demonstrated. Reduced cell infiltration, demyelination, axonal damage and a shift of T-helper cell responses have been shown. Accordingly, in human studies, a decrease of pro-inflammatory and an increase of anti-inflammatory cytokines have been measured and a significant reduction of disease progression and a decrease in brain volume loss has been demonstrated. During all clinical studies a favorable safety profile was observed for 0.6mg laquinimod. New information about cardiovascular events is prompting the discontinuation of higher dosing regimens in both ongoing trials. EXPERT OPINION: Laquinimod is a first in class oral agent with high potential to reduce disease progression in RRMS and PPMS. Owing to its favorable safety profile, a combination with 0.6mg laquinimod and other disease modifying therapies could be an option in future MS therapy.

Forced Exercise Preconditioning Attenuates Experimental Autoimmune Neuritis by Altering Th1 Lymphocyte Composition and Egress.

A short-term exposure to moderately intense physical exercise affords a novel measure of protection against autoimmune-mediated peripheral nerve injury. Here, we investigated the mechanism by which forced exercise attenuates the development and progression of experimental autoimmune neuritis (EAN), an established animal model of Guillain-Barré syndrome. Adult male Lewis rats remained sedentary (control) or were preconditioned with forced exercise (1.2 km/day × 3 weeks) prior to P2-antigen induction of EAN. Sedentary rats developed a monophasic course of EAN beginning on postimmunization day 12.3 ± 0.2 and reaching peak severity on day 17.0 ± 0.3 (N = 12). By comparison, forced-exercise preconditioned rats exhibited a similar monophasic course but with significant (p < .05) reduction of disease severity. Analysis of popliteal lymph nodes revealed a protective effect of exercise preconditioning on leukocyte composition and egress. Compared with sedentary controls, forced exercise preconditioning promoted a sustained twofold retention of P2-antigen responsive leukocytes. The percentage distribution of pro-inflammatory (Th1) lymphocytes retained in the nodes from sedentary EAN rats (5.1 ± 0.9%) was significantly greater than that present in nodes from forced-exercise preconditioned EAN rats (2.9 ± 0.6%) or from adjuvant controls (2.0 ± 0.3%). In contrast, the percentage of anti-inflammatory (Th2) lymphocytes (7-10%) and that of cytotoxic T lymphocytes (∼20%) remained unaltered by forced exercise preconditioning. These data do not support an exercise-inducible shift in Th1:Th2 cell bias. Rather, preconditioning with forced exercise elicits a sustained attenuation of EAN severity, in part, by altering the composition and egress of autoreactive proinflammatory (Th1) lymphocytes from draining lymph nodes.

Retinoic acid receptor stimulation ameliorates experimental autoimmune optic neuritis.

BACKGROUND: To determine whether all-trans retinoic acid or a synthetic retinoic acid receptor-α/ß-specific agonist, Am80, can reduce the degree of experimental autoimmune optic neuritis in mice with experimental autoimmune encephalomyelitis. METHODS: Optic neuritis was induced in C57BL/6 mice by immunizing them with myelin oligodendrocyte glycoprotein35-55 . All-trans retinoic acid (350 µg/mouse/time point) or Am80 (5 mg/kg/time point) was administered every other day from day 0 to day 20. The degree of experimental autoimmune encephalomyelitis was scored and histopathological analysis of the optic neuritis was performed on day 22 after the immunization. In vivo-primed draining lymph node cells obtained from vehicle-treated or all-trans retinoic acid-treated mice were stimulated with myelin oligodendrocyte glycoprotein35-55 , and the culture supernatant was collected for assays of interferon-γ and interleukin-17. RESULTS: All-trans retinoic acid treatment significantly reduced the clinical score of experimental autoimmune encephalomyelitis and the severity of the optic neuritis by histopathological analysis. The production of interferon-γ and interleukin-17 was significantly reduced in all-trans retinoic acid-treated mice compared with vehicle-treated mice. Am80 treatment also significantly decreased the severity of the optic neuritis in mice with experimental autoimmune encephalomyelitis. CONCLUSIONS: These findings demonstrate that all-trans retinoic acid and Am80 treatment were able to reduce the severity of optic neuritis in mice with experimental autoimmune encephalomyelitis. Activation of retinoic acid receptor-α/ß may be a molecular target for the treatment of autoimmune optic neuritis induced by Th1 or Th17-dominated immune responses.

Dendritic cells treated with crude Plasmodium berghei extracts acquire immune-modulatory properties and suppress the development of autoimmune neuroinflammation.

Dendritic cells (DCs) are professional antigen-presenting cells specifically targeted during Plasmodium infection. Upon infection, DCs show impaired antigen presentation and T-cell activation abilities. In this study, we aimed to evaluate whether cellular extracts obtained from Plasmodium berghei-infected erythrocytes (PbX) modulate DCs phenotypically and functionally and the potential therapeutic usage of PbX-modulated DCs in the control of experimental autoimmune encephalomyelitis (EAE, the mouse model for human multiple sclerosis). We found that PbX-treated DCs have impaired maturation and stimulated the generation of regulatory T cells when cultured with naive T lymphocytes in vitro. When adoptively transferred to C57BL/6 mice the EAE severity was reduced. Disease amelioration correlated with a diminished infiltration of cytokine-producing T cells in the central nervous system as well as the suppression of encephalitogenic T cells. Our study shows that extracts obtained from P. berghei-infected erythrocytes modulate DCs towards an immunosuppressive phenotype. In addition, the adoptive transfer of PbX-modulated DCs was able to ameliorate EAE development through the suppression of specific cellular immune responses towards neuro-antigens. To our knowledge, this is the first study to present evidence that DCs treated with P. berghei extracts are able to control autoimmune neuroinflammation.

Chrysin attenuates experimental autoimmune neuritis by suppressing immuno-inflammatory responses.

Guillain-Barré syndrome (GBS) is an acute, post-infectious, immune-mediated, demyelinating disease of peripheral nerves and nerve roots. Experimental autoimmune neuritis (EAN) is an animal model of GBS. Chrysin, which is a naturally occurring flavonoid, exhibits various biological activities. This study was designed to investigate the anti-inflammatory and neuroprotective properties of preventative and therapeutic chrysin treatment in EAN rats. For preventative treatment, chrysin was administered orally from day 1 to day 16 (50mg/kg once daily) while, for therapeutic treatment, rats received chrysin from day 7 to day 16 at the same dose once daily. Control animals received the same volume of the vehicle (phosphate-buffered saline/2% dimethylsulfoxide). Regardless of the treatment regimen, chrysin attenuated the severity and duration of the clinical course of EAN and reduced inflammatory cell infiltration and demyelination of sciatic nerves. In the sciatic nerves, the expression of inducible nitric oxide synthase, cyclooxygenase-2 and nuclear factor kappa B was reduced. Furthermore, chrysin inhibited the splenic mononuclear cell secretion of interleukin-1ß, interleukin-2, interleukin-6, inteleukin-12, interferon γ and tumor necrosis factor α, and elevated the level of inteleukin-4. In summary, our data demonstrate that chrysin is a potentially useful agent for the treatment of EAN with its anti-inflammatory and neuroprotective effects.

Berberine ameliorates experimental autoimmune neuritis by suppressing both cellular and humoral immunity.

Berberine (BBR), an isoquinoline derivative alkaloid, has been extensively used in traditional Chinese medicine for the treatment of diarrhoea, rheumatic diseases, diabetes, etc. Recent studies have demonstrated new biological properties of BBR and suggested the possibility of BBR to be a therapeutic agent for some autoimmune diseases. To explore the effect of BBR on the development of experimental autoimmune neuritis (EAN), BBR was administered intragastrically daily to Lewis rats immunized with P0 peptide 180-199 in Freund's complete adjuvant. We found BBR treatment resulted in amelioration of EAN, accompanied by suppressed lymphocyte (in particular CD4(+) T cell) proliferation, downregulated Th1 (TNF-α) and Th2 (IL-10) cytokines and reduced anti-P0 peptide 180-199 IgG1 and IgG2a. In brief, BBR played a role in ameliorating EAN by suppressing both cellular and humoral immunity. Thus, our study suggests that BBR may be a potential therapeutic agent for the autoimmune disease in the peripheral nervous system, such as Guillain-Barré syndrome.

Suppression of murine experimental autoimmune optic neuritis by mature dendritic cells transfected with calcitonin gene-related Peptide gene.

PURPOSE: Calcitonin gene-related peptide (CGRP) exhibits prominent anti-inflammatory actions. We examined whether CGRP-transfected dendritic cells (DC) prevent the development of experimental autoimmune optic neuritis (EAON) and experimental autoimmune encephalomyelitis (EAE). METHODS: A human CGRP-expressing plasmid was constructed, and used to transfect C57BL/6 mouse bone marrow-derived matured DC (mDC) by electroporation METHODS: Transfection efficiency was 50% with 80% cell viability. C57BL/6 mice were immunized with myelo-oligodendrocyte glycoprotein 35-55, and injected intravenously with CGRP-expressing mDC (CGRP gene-transfected group) or mock-transfected mDC (mock-transfected group) at the induction or effector phase. EAE was diagnosed clinically and EAON was assessed histopathologically. Delayed hypersensitivity was measured. Supernatants of spleen cell cultures were assayed for cytokines using ELISA. The CD4(+)CD25(+)Foxp3(+) fraction in spleen cells was analyzed using flow cytometry. RESULTS: For gene therapy in the induction phase, EAE developed in 50% of mice in the CGRP-transfected group compared with 80% in the mock-transfected group, and the mean pathological score for EAON was 1 in the CGRP-transfected group compared with 2 in the mock-transfected group (P < 0.05). For gene therapy in the effector phase, the mean EAE clinical score (1.5 vs. 3.0) and mean EAON pathological score (1.0 vs. 2.0) were both lower in the CGRP-transfected group compared with the mock-transfected group (P < 0.05). Delayed hypersensitivity was suppressed significantly in the CGRP-transfected group. IL-10 production by spleen cells in the CGRP-transfected group increased independent of MOG concentration, compared with the mock-transfected group. Interestingly, the proportion of CD4(+)CD25(+)Foxp3(+) cells increased significantly (P < 0.05) in the CGRP-transfected group compared with the mock-transfected group. CONCLUSIONS: Gene therapy with CGRP-expressing mDC was effective in suppressing the development of EAON and EAE.

Preventive and therapeutic effects of the selective Rho-kinase inhibitor fasudil on experimental autoimmune neuritis.

We studied the effects of fasudil, a selective Rho-kinase inhibitor, on experimental autoimmune neuritis (EAN). Continuous parenteral administration of fasudil prevented the development of EAN induced by P0 peptide 180-199 in Lewis rats while it also reduced EAN severity when administered after disease onset. Immunohistochemical examination disclosed a marked decrease in the amount of inflammatory cell infiltration and attenuation of demyelination and axonal degeneration. Specific proliferation of lymphocytes from fasudil-treated rats in response to P0 peptide was significantly reduced as compared with those from phosphate-buffered saline (PBS)-treated rats. Fasudil treatment was associated with a significant reduction in secretion of IFN-γ; by contrast, secretion of IL-4 was almost the same in the fasudil- and PBS-treated groups. As a result, the IFN-γ/IL-4 ratio in the supernatant was significantly deceased in fasudil-treated rats compared with PBS-treated ones. Therefore, our results indicate a beneficial effect of selective blockade of Rho-kinase in animals with autoimmune inflammation of the peripheral nerves, and may provide a rationale for the selective blockade of Rho-kinase as a new therapy for Guillain-Barré syndrome.

Valproic acid attenuates inflammation in experimental autoimmune neuritis.

Valproic acid (VPA) is a short-chain branched fatty with anti-inflammatory, neuro-protective and axon-remodeling effects. We investigated the effects of VPA in rats in which experimental autoimmune neuritis (EAN) had been induced (EAN rats). VPA (300 mg/kg, intraperitoneally) administration to EAN rats once daily immediately following immunization significantly suppressed mRNA levels of interferon-gamma, tumor necrosis factor-alpha, interleukin (IL)-1beta, IL-4, IL-6 and IL-17 in the lymph nodes of EAN rats. In peripheral blood and sciatic nerves of EAN rats, Foxp3(+) cells were increased but IL-17(+) cells were decreased during VPA treatment. Furthermore, suppressive and therapeutic treatment with VPA greatly attenuated both accumulation of macrophages, T cells and B cells, and demyelination in sciatic nerves, and greatly reduced the severity and duration of EAN. In summary, our data demonstrated that VPA could effectively suppress inflammation in EAN, suggesting that VPA could be a potent candidate for treatment of autoimmune neuropathies.

The effect of treatment with crotapotin on the evolution of experimental autoimmune neuritis induced in Lewis rats.

Biomedical research in which venom components are being investigated for their potential as novel therapeutic agents has emerged as an interesting option. Crotapotin, which is purified from the venom of the rattlesnake Crotalus durissus terrificus, has been described as an anti-inflammatory agent that acts on the innate arm of the immune response. Here we have demonstrated that intraperitoneal administration of crotapotin significantly reduces the severity of experimental autoimmune neuritis (EAN), an experimental model for Guillain-Barré syndrome. The reduction of the severity of the disease is associated with a reduction in the mononuclear cells infiltrating the sciatic nerve and a significant decrease in the lymphocyte proliferative response to neuritogenic peptide.

Effects of interferon-beta-1a on neuronal survival under autoimmune inflammatory conditions.

Interferon-beta-1a (IFN-beta-1a) is an approved treatment for multiple sclerosis (MS). It improves the disease course by reducing the relapse rate as well as the persistent neurological deficits. Recent MRI and post-mortem studies revealed that neuronal and axonal damage are most relevant for chronic disability in MS patients. We have characterized previously time course and mechanisms of neuronal apoptosis in a rat model of myelin oligodendrocyte glycoprotein (MOG)-induced optic neuritis. In this animal model, application of IFN-beta-1a three times per week slightly decreases the loss of retinal ganglion cells (RGCs), the neurons that form the axons within the optic nerve. In contrast to neurotrophic factors, this cytokine does not directly protect cultured RGCs from apoptosis. We conclude that IFN-beta-1a is a suitable candidate to be combined with a directly neuroprotective agent in order to further decrease axonal and neuronal degeneration in MS patients.

Nasal administration of recombinant rat alpha3(IV)NC1 prevents the development of experimental autoimmune glomerulonephritis in the WKY rat.

Experimental autoimmune glomerulonephritis (EAG), an animal model of Goodpasture's disease, can be induced in Wistar Kyoto (WKY) rats by immunization with either collagenase-solubilized rat glomerular basement membrane (GBM) or the recombinant NC1 domain of the alpha3 chain of type IV collagen [alpha3(IV)NC1]. EAG is characterized by circulating and deposited anti-glomerular basement membrane antibodies, focal necrotizing glomerulonephritis with crescent formation, and glomerular infiltration by T cells and macrophages. Previous studies have demonstrated that oral administration of collagenase-solubilized GBM to WKY rats prevented the development of EAG. Nasal administration of specific autoantigens has been reported to be more effective than oral administration in other models of autoimmune disease. The main aim of this study was to investigate further the concept of mucosal tolerance in EAG by examining the effect of nasal administration of recombinant rat alpha3(IV)NC1. Groups of WKY rats with EAG, induced by immunization with recombinant rat alpha3(IV)NC1, were given alpha3(IV)NC1 nasally on 3 consecutive days before immunization, at total cumulative doses of 25, 100, or 250 microg per rat. A dose-dependent effect was observed on the development of EAG. A dose of 25 microg had no effect on disease; 100 microg resulted in a moderate reduction in the severity of nephritis; and 250 microg led to a marked reduction in circulating and deposited antibodies, albuminuria, severity of glomerular abnormalities, and numbers of glomerular CD8+ T cells and macrophages. In addition, there was a reduction in the proliferative response of splenocytes from rats in the high dose group (250 microg) to alpha3(IV)NC1 in vitro. The results from this study clearly demonstrate for the first time that mucosal tolerance in EAG can be induced by nasal administration of recombinant rat alpha3(IV)NC1 and that this approach is effective in the prevention of crescentic glomerulonephritis. Further work using new antigen-specific treatment strategies may provide a novel approach to the treatment of patients with anti-glomerular basement membrane disease.

Treatment and prevention of experimental autoimmune neuritis with superagonistic CD28-specific monoclonal antibodies.

Two distinct CD28-specific mAb were used in treatment of active or adoptive transfer (AT)-experimental autoimmune neuritis (EAN): "superagonistic" JJ316 activates T cells without T cell receptor (TCR) occupancy, and conventional JJ319 activates T cells only in the presence of TCR-stimulation. Treatment with JJ316 during induction phase of active and adoptive-transfer experimental autoimmune encephalomyelitis (AT-EAN) dramatically reduced disease severity and improved nerve function as revealed by electrophysiology. JJ316 given 1 week before immunization had a preventive effect. By immunohistology, JJ316 markedly reduced TC infiltration of the sciatic nerve in active and AT-EAN. JJ319 was less effective. Ex vivo, JJ316 therapy reduced P2-specific proliferation and interferon-gamma (IFN-gamma) production of lymph node cells. We demonstrate preventive and therapeutic effects of a "superagonistic" mAb-mediated, TCR-independent CD28 stimulation in EAN, possibly with implications for therapy of autoimmune-inflammatory disorders.

Suppression of experimental autoimmune neuritis by ABR-215062 is associated with altered Th1/Th2 balance and inhibited migration of inflammatory cells into the peripheral nerve tissue.

The therapeutic effects of ABR-215062, which is a new immunoregulator derived from Linomide, have been evaluated in experimental autoimmune neuritis (EAN), a CD4(+) T cell-mediated animal model of Guillain-Barré syndrome in man. In previous studies, we reported that Linomide suppressed the clinical EAN and myelin antigen-reactive T and B cell responses. Here EAN induced in Lewis rats by inoculation with peripheral nerve myelin P0 protein peptide 180-199 and Freund's complete adjuvant was strongly suppressed by ABR-215062 administered daily subcutaneously from the day of inoculation. ABR-215062 dose-dependently reduced the incidence of EAN, ameliorated clinical signs and inhibited P0 peptide 180-199-specific T cell responses as well as also the decreased inflammation and demyelination in the peripheral nerves. The suppression of clinical EAN was associated with inhibition of the inflammatory cytokines IFN-gamma and TNF-alpha, as well as the enhancement of anti-inflammatory cytokine IL-4 in lymph node cells and periphery nerve tissues, respectively, in a dose-dependent manner. These effects indicate that ABR-215062 may mediate its effects by regulation of Th1/Th2 cytokine balance and suggest that ABR-215062 is potentially a new chemical entity for effective treatment of autoimmune diseases.

Vaccination, prevention, and treatment of experimental autoimmune neuritis (EAN) by an oligomerized T cell epitope.

Using a polypeptide oligomer harboring 16 repeats of the neuritogenic epitope (aa 58-73) of myelin P2 protein separated by spacers, enhancement of the immune response to the P2 protein, an important neuritogenic autoantigen in experimental autoimmune neuritis (EAN), was attempted. In contrast to a previous study with PLP-16-mer antigen-specific response of T cells was attenuated at all doses examined to a variable degree. Treatment of Lewis rats with the P2-16-mer up to 2 months before immunization with P2(53-78) (vaccination) or after immunization but before appearance of disease (prevention) had a strong tolerizing effect against the induction of EAN on immunization with P2(53-78). Moreover, rats injected with 200 microg of the P2-16-mer i.v. on day 11 after disease induction, at which time the initial signs of disease had appeared, were almost completely protected against progression of clinical disease, whereas animals treated with the same amount of monomeric control peptide developed severe disease (treatment). Similar results were obtained by i.v. treatment of adoptive-transfer EAN with the P2-16-mer. The lack of clinical signs of disease after 16-mer therapy could be correlated with a reduced proliferative response of P2(53-78)-specific lymph node cells. The frequency of apoptotic T cells in sciatic nerve or in lymph node cells, however, was not increased by the 16-mer treatment, suggesting that induction of anergy or other forms of peripheral tolerance may be responsible for the effect. Thus, the oligomerized P2 peptide antigen was highly effective in all three treatment modalities examined in this specific autoreactive T cell-mediated immune response.

Suppression of experimental autoimmune neuritis by leflunomide.

Leflunomide is a new immunosuppressive drug whose active metabolite, A77 1726, impairs cellular nucleotide metabolism by inhibiting the dihydroorotate dehydrogenase (DHODH), a rate-limiting enzyme of de novo pyrimidine synthesis. Furthermore, A77 1726 suppresses tyrosine kinases involved in signal transduction pathways. We investigated the immunosuppressive effects of leflunomide in experimental autoimmune neuritis (EAN) in rats, which is a model of immune-mediated neuropathies. In EAN that was actively induced by subcutaneous injection of peripheral nerve myelin, leflunomide completely prevented paraparesis if applied orally from the day of immunization. Leflunomide was much more effective than azathioprine, which did not mitigate EAN at all. Even when leflunomide was administered therapeutically after the appearance of the first neuropathical signs, it halted the progression and markedly reduced the severity and duration of EAN. Inflammatory infiltrates, demyelination and axonal degeneration in sciatic nerve sections of leflunomide-treated EAN rats were strongly reduced. Leflunomide-treated rats did not mount autoantibodies as specified by ELISA (enzyme-linked immunosorbent assay) with a mixture of peripheral myelin proteins, including P2 and myelin basic protein. In EAN that was adoptively transferred by injection of neuritogenic cells of a P2-specific T-helper line, application of leflunomide also clearly reduced signs of disease. Additional injection of uridine did not neutralize the effect of leflunomide. Similarly, transfer of neuritogenic P2-specific T cells, which were activated in the presence of A77 1726 plus uridine in vitro, still resulted in reduced severity of adoptive transfer EAN in vivo, although proliferation of these cells in vitro was identical to that of control cells. The T-cell receptor-mediated in vitro activatability of a P2-specific T-cell hybridoma was diminished by high concentrations of A77 1726, as evidenced by reduced Ca(2+) flux into the cytosol. Together with the findings in adoptive transfer EAN, this indicates that the antiproliferative effect is probably not the only mechanism of immunosuppressive action by leflunomide. In summary, leflunomide suppresses EAN efficiently and may constitute a promising therapy for immune-mediated neuropathies.

Transfer of myelin-specific cells deviated in vitro towards IL-4 production ameliorates ongoing experimental allergic neuritis.

A causal role of IL-4 (Th2) production for recovery in experimental allergic neuritis (EAN) was indicated by experiments where Th1-like autoreactive cell populations, taken from the induction phase of the disease, were deviated to extensive secretion of IL-4 in a selective fashion, by ex vivo stimulation with autoantigen in the presence of IL-4. The deviated cells were adoptively transferred to EAN rats at a time just prior to the onset of clinical signs. This treatment ameliorated EAN compared with sham treatment. This therapeutic approach, with generation of autoreactive IL-4-secreting cells ex vivo followed by subsequent adoptive transfer, may become a new selective treatment of organ-specific autoimmune diseases since, in contrast to previous attempts, it is done in a physiological and technically easy way.

Characterization of T cell receptor associated with the development of P2 peptide-induced autoimmune neuritis.

To characterize experimental autoimmune neuritis (EAN)-inducing T cells in more detail, we performed CDR3 spectratyping analysis and found oligoclonal expansion of several Vbeta spectratypes in nerve-infiltrating T cells. Vbeta5 expansion was observed all the stages examined, whereas Vbeta8.2 and Vbeta17 expansion was mainly found at the peak and preclinical stages, respectively. Since Vbeta5 expansion persists throughout the course of the disease, Vbeta5+ T cells are judged to be the main effector cells. Vbeta8.2+ and Vbeta17+ T cells may also be pathogenic but are not the main effectors because expansion of these spectratypes was found at a limited period of time. Sequence analysis revealed that Vbeta5, Vbeta8.2 and Vbeta17 spectratype-derived TCR clones possess their own dominant sequences in the CDR3 region with no homology among the clones. These findings suggest that polyclonally activated T cells are involved in the formation of the nerve lesion. Furthermore, vaccination with Vbeta5 DNA, but not with Vbeta10 DNA, suppressed the development of EAN significantly. Collectively, these findings indicate that determination of autoimmune disease-associated TCR by CDR3 spectratyping provides useful information for designing TCR-based immunotherapy for the disease.

Antigen-specific immunosuppression: nasal tolerance to P0 protein peptides for the prevention and treatment of experimental autoimmune neuritis in Lewis rats.

Experimental autoimmune neuritis (EAN) is an autoimmune inflammatory demyelinating disease of the peripheral nervous system (PNS), and represents an animal model of the human Guillain-Barré syndrome (GBS). In this study, we report that nasal administration of the neuritogenic peptide 180-199 and of the cryptic peptide 56-71 of the rat neuritogenic P0 protein of peripheral nerve myelin prevents EAN and attenuates ongoing EAN. Both peptides effectively decreased the severity and shortened clinical EAN. Both a prophylactic and a therapeutic approach proved to be beneficial. These effects were associated with T and B cells hyporesponsiveness to the peptide antigens, reflected by downregulated Th1 cell responses (interferon-gamma secretion) and macrophage function, whereas Th2 cell responses (IL-4 secretion) and transforming growth factor-beta mRNA expression were upregulated.