Effects of microRNA-338 Transfection into Sciatic Nerve on Rats with Experimental Autoimmune Neuritis.

Nerve demyelination or axonal lesions are characteristic of experimental autoimmune neuritis (EAN). Previous studies have demonstrated that microRNA-338 can regulate the differentiation and maturation of oligodendrocytes and Schwann cells and promote injured peripheral nerves in rats. In this study, we used microRNA-338 coded lentivirus vector (miR-338-LV) in a Lewis rat EAN model, in with the conjunction P0 peptide 180-199 which was injected into the footpads of animals to induce immunization. The clinical scores of miR-338-LV and intravenous immunoglobulin (IVIg) (positive drug) groups were significantly superior to those of untreated group at disease peak and disease plateau (p < 0.05). The nerve conduction velocity and the compound nerve action potential amplitude of miR-338-LV and IVIg groups increased significantly compared to those of the untreated group at disease peak (p < 0.01). At disease peak, myelin swelling, cavity formation, and lamellae separation showed improvement in miR-338-LV and IVIg groups compared to untreated group. S100 and NF200 expression in miR-338-LV and IVIg groups increased compared to that in untreated group. Iba1 and S100 co-expression in Schwann cells in miR-338-LV and IVIg groups decreased compared to that in untreated group, which was indicative of the reduced conversion of Schwann cells into inflammatory cells. Overall, miR-338-LV in sciatic nerves might improve neuromuscular function in EAN by inhibiting the conversion of Schwann cells into inflammatory cells.

An autophagy-targeting peptide to treat chronic inflammatory demyelinating polyneuropathies.

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an autoimmune disease of the peripheral nerves evolving with diffuse sensory and motor symptoms. Although it is claimed that in neurodegenerative pathologies, a common feature is the failure of proteolytic systems to adequately eliminate aggregated or misfolded proteins, it has not been addressed whether autophagy, a central "clearance" system delivering damaged intracellular components to lysosomes, is affected in CIDP. The focus of the present investigation was therefore to determine if some defects exist in autophagy processes in this setting and if they can be corrected or minimized using an appropriate treatment targeting this survival pathway. Experiments were performed using a rat model mimicking human CIDP, also known as chronic experimental autoimmune neuritis (c-EAN), the disease establishment and development of which was followed at both the clinical and biological levels (indices of disease severity, histopathological alteration, cytokines and antibodies rates). Based on immunofluorescence and western immunoblotting experiments on sciatic nerves and spleen cells from c-EAN rats, we demonstrate that both, macroautophagy and chaperone-mediated autophagy (CMA), are significantly altered in non-neuronal cells of the peripheral nervous system. We show further that a 21-mer synthetic phosphopeptide called P140, known to target CMA and successfully used in pathological settings where CMA markers are overexpressed, considerably ameliorates the clinical and biological course of the disease in c-EAN rats. P140 displayed prophylactic and therapeutic effects, both in terms of disease intensity and chronicity, and preserved sciatic nerves from disease-related damages. Our findings uncover new disrupted molecular pathways in a c-EAN model and provide a proof-of-concept that targeting CMA might represent a promising therapeutic strategy for treating inflammatory neuropathies for which no disease-specific treatment is currently available.

Roles of macrophage migration inhibitory factor in Guillain-Barré syndrome and experimental autoimmune neuritis: beneficial or harmful?

INTRODUCTION: Macrophage migration inhibitory factor (MIF) plays an important role in the pathogenesis of Guillain-Barré syndrome (GBS) and its animal model experimental autoimmune neuritis (EAN), which may offer an opportunity for the development of the novel therapeutic strategies for GBS. Areas covered: 'macrophage migration inhibitory factor' and 'Guillain-Barré syndrome' were used as keywords to search for related publications on Pub-Med, National Center for Biotechnology Information (NCBI), USA. MIF is involved in the etiology of various inflammatory and autoimmune disorders. However, the roles of MIF in GBS and EAN have not been summarized in the publications we identified. Therefore, in this review, we described and analyzed the major roles of MIF in GBS/EAN. Primarily, this molecule aggravates the inflammatory responses in this disorder. However, multiple studies indicated a protective role of MIF in GBS. The potential of MIF as a therapeutic target in GBS has been recently demonstrated in experimental and clinical studies, although clinical trials have been unavailable to date. Expert opinion: MIF plays a critical role in the initiation and progression of GBS and EAN, and it may represent a potential therapeutic target for GBS.

Treatment of Guillain-Barré syndrome with Bifidobacterium infantis through regulation of T helper cells subsets.

BACKGROUND: Guillain-Barré syndrome (GBS) is a rare, autoimmune-mediated disease. The use of Bifidobacterium is reportedly effective in alleviating GBS since they act by regulating T helper (Th) cells. OBJECTIVES: In this study, we explored the differentiation of T helper cell subsets in patients with GBS. We also evaluated the effect of GBS on Bifidobacterium levels in patients and the likely protective influence of this bacterium in alleviating the disease in an animal model. MATERIALS AND METHODS: We used flow cytometry, and real-time polymerase chain reaction (PCR) to determine the T cell subsets differentiation among 30 GBS patients and 20 healthy controls (HC). The concentration of Bifidobacterium was assayed by real-time PCR. Experimental autoimmune neuritis (EAN) animal model was established to support the protective role of Bifidobacterium in GBS. RESULTS: The expression of Th cells, Th2 and Th17 in the patients was significantly higher than that in the HC, while Treg cells decreased substantially. Moreover, the levels of Bifidobacterium in the GBS patients were considerably lower than those in the HC, the concentration of Bifidobacterium correlating with Th2 and Th17 subsets negatively. Treatment with Bifidobacterium significantly reduced the levels of Th2 and Th17 and promoted the levels of Treg cells. CONCLUSIONS: We concluded from this study that Bifidobacterium alleviated GBS by regulating Th cells, although in-depth studies might be required to fully understand the mechanism of action.

Therapeutic Effect of CD4+CD25+ Regulatory T Cells Amplified In Vitro on Experimental Autoimmune Neuritis in Rats.

BACKGROUND/AIMS: This study aimed to explore whether the adoptive transfusion of autologous CD4+CD25+ regulatory T cells (CD4+CD25+ Tregs) has a therapeutic effect on Experimental autoimmune neuritis (EAN) model rats, and it provides new experimental and theoretical bases for the immunotherapy of Guillain-Barre syndrome (GBS). METHODS: CD4+CD25+ Tregs were sorted from the spleens of rats using immunomagnetic bead separation techniques combined with flow cytometry. Their in vitro inhibitory function was determined using a lymphocyte proliferation inhibition test, and their purity was confirmed by flow cytometry. Cells were stimulated using CD3/CD28 monoclonal antibodies and were cultured in culture medium containing interleukin 2 (IL-2), transforming growth factor-ß (TGF-ß) and rapamycin. After 15 days of amplification, CD4+CD25+ Tregs were collected and transfused into EAN model rats. Changes in the pathology and electron microscopical morphology of rat sciatic nerves in the normal group, untreated group, low-dose group (2 × 107) and high-dose group (4 × 107) were observed, and the expression of CD4+CD25+FOXP3 in peripheral blood in the four groups of rats was detected by flow cytometry. RESULTS: Compared with rats in the untreated group, rats in the treatment groups had significantly reduced infiltration of inflammatory cells in the sciatic nerve, as well as myelin and axonal damage. Additionally, the CD4+CD25+ Tregs levels in peripheral blood were significantly higher than those in the untreated group (P< 0. 05). Moreover, the therapeutic effect became more significant with an increase in the dose of adoptive transfusion. CONCLUSION: Adoptive transfusion of CD4+CD25+ Tregs into EAN model rats has significant therapeutic effects.

Programmed Death Ligand 1 Plays a Neuroprotective Role in Experimental Autoimmune Neuritis by Controlling Peripheral Nervous System Inflammation of Rats.

Programmed death 1 (PD-1; CD279), a member of the CD28 family, is an inhibitory receptor on T cells and is responsible for T cell dysfunction in infectious diseases and cancers. The ligand for PD-1, programmed death ligand 1 (PD-L1; also known as B7-H1, CD274), is a member of the B7 family. The engagement of PD-1 with programmed death ligand can downregulate autoreactive T cells that participate in multiple autoimmune diseases. Experimental autoimmune neuritis (EAN) is an animal model of Guillain-Barré syndrome, and the pathogenesis of EAN is mediated principally through T cells and macrophages. In this study, we investigated the effects of PD-L1 in EAN rats. For preventative and therapeutic management, we administered PD-L1, which successfully decreased the severity of EAN; it alleviated the neurologic course of EAN, as well as inhibited the infiltration of inflammatory cells and demyelination of sciatic nerves. Our data revealed that PD-L1 treatment inhibited lymphocyte proliferation and altered T cell differentiation by inducing decreases in IFN-γ+CD4+ Th1 cells and IL-17+CD4+ Th17 cells and increases in IL-4+CD4+ Th2 cells and Foxp3+CD4+ regulatory T cells. The expression levels of p-STAT3 and Foxp3 were significantly different in PD-L1-treated groups compared with the control group. Additionally, PD-L1 regulated the expression of Foxp3 and p-STAT3 in EAN, probably by inhibiting PI3K/AKT/mTOR signaling expression. In summary, PD-L1 is a potentially useful agent for the treatment of EAN because of its anti-inflammatory and neuroprotective effects.

Suppressive oligodeoxynucleotides induced tolerogenic plasmacytoid dendritic cells and ameliorated the experimental autoimmune neuritis.

Toll-like receptor (TLR) 9, recognizing different ligands, confers distinct features of plasmacytoid dendritic cells (pDCs). Our previous study demonstrated a role for TLR9 in the mechanism of experimental autoimmune neuritis (EAN). In this study, we explored whether suppressive oligodeoxynucleotides (sODN) could induce tolerogenic pDCs via TLR9 and thus promote the recovery of EAN. Effects of different TLR9 ligands, CpG ODN and sODN on P0 180-199 peptide-stimulated pDCs were measured by detecting the expression of co-stimulatory molecules, indoleamine 2,3-dioxygenase (IDO), secretion of Th1- and Th2-type cytokines and the TLR9 signaling pathway. CpG ODN- or sODN-treated pDCs were intravenously injected into the EAN mice and their effects were compared. Our data showed that P0180-199 peptides significantly promoted mRNA expression of co-stimulatory molecules (CD40, CD80 and CD86) in pDCs and induced secretion of Th1-type cytokines. Treatment of CpG ODN aggravated the effects of P0 180-199 peptides on pDCs; however, sODN had the opposite effects and significantly upregulated the IDO expression in pDCs. Further analysis showed that MYD88 is necessary for sODN to modulate the TLR9/NF-κB signaling in pDCs. Finally, the sODN-treated pDCs significantly promoted recovery of the EAN mice. Taken together, sODN could induce tolerogenic pDCs and thus ameliorate the EAN.

CCR2 gene deletion and pharmacologic blockade ameliorate a severe murine experimental autoimmune neuritis model of Guillain-Barré syndrome.

The molecular determinants and signaling pathways responsible for hematogenous leukocyte trafficking during peripheral neuroinflammation are incompletely elucidated. Chemokine ligand/receptor pair CCL2/CCR2 has been pathogenically implicated in the acute inflammatory demyelinating polyradiculoneuropathy variant of Guillain-Barré syndrome (GBS). We evaluated the role of CCR2 in peripheral neuroinflammation utilizing a severe murine experimental autoimmune neuritis (sm-EAN) model. Sm-EAN was induced in 8-12 week old female SJL CCR2 knockout (CCR2KO), heterozygote (CCR2HT) and wild type (CCR2WT) mice, and daily neuromuscular severity scores and weights recorded. In vitro and in vivo splenocyte proliferation and cytokine expression assays, and sciatic nerve Toll-like receptor (TLR) 2, TLR4 and CCL2 expression assays were performed to evaluate systemic and local innate immune activation at disease onset. Motor nerve electrophysiology and sciatic nerve histology were also performed to characterize the inflammatory neuropathy at expected peak severity. To further determine the functional relevance of CCR2 in sm-EAN, 20 mg/kg CCR2 antagonist, RS 102895 was administered daily for 5 days to a cohort of CCR2WT mice following sm-EAN disease onset, with efficacy compared to 400 mg/kg human intravenous immunoglobulin (IVIg). CCR2KO mice were relatively resistant to sm-EAN compared to CCR2WT and CCR2HT mice, associated with attenuated peripheral nerve demyelinating neuritis. Partial CCR2 gene deletion did not confer any protection against sm-EAN. CCR2KO mice demonstrated similar splenocyte activation or proliferation profiles, as well as TLR2, TLR4 and CCL2 expression to CCR2WT or CCR2HT mice, implying a direct role for CCR2 in sm-EAN pathogenesis. CCR2 signaling blockade resulted in rapid, near complete recovery from sm-EAN following disease onset. RS 102895 was significantly more efficacious than IVIg. CCR2 mediates pathogenic hematogenous monocyte trafficking into peripheral nerves, with consequential demyelination in sm-EAN. CCR2 is amenable to pharmacologic blockade, making it a plausible drug target for GBS.

CD19 as a therapeutic target in a spontaneous autoimmune polyneuropathy.

Spontaneous autoimmune polyneuropathy (SAP) in B7-2 knock-out non-obese diabetic (NOD) mice is mediated by myelin protein zero (P0)-reactive T helper type 1 (Th1) cells. In this study, we investigated the role of B cells in SAP, focusing on CD19 as a potential therapeutic target. We found that P0-specific plasmablasts and B cells were increased in spleens of SAP mice compared to wild-type NOD mice. Depletion of B cells and plasmablasts with anti-CD19 monoclonal antibody (mAb) led to attenuation of disease severity when administered at 5 months of age. This was accompanied by decreased serum immunoglobulin (Ig)G and IgM levels, depletion of P0-specific plasmablasts and B cells, down-regulation/internalization of surface CD19 and increased frequency of CD4(+) regulatory T cells in spleens. We conclude that B cells are crucial to the pathogenesis of SAP, and that CD19 is a promising B cell target for the development of disease-modifying agents in autoimmune neuropathies.

Transplantation of Schwann cells co-cultured with brain-derived neurotrophic factor for the treatment of experimental autoimmune neuritis.

The aim of this study was to investigate the effects of transplantation of Schwann cells (SCs) co-cultured with brain-derived neurotrophic factor (BDNF) for the treatment of experimental autoimmune neuritis (EAN). Primary SCs were co-cultured with various BDNF concentrations, and the optimum concentration was determined by cell proliferation, and NGF and FGF levels. A rat model of EAN was established by immunization with 400µg of P2 peptide dissolved in Freund's complete adjuvant. SCs were labeled with CFSE and injected into the cisterna magna 14days after immunization. We found proliferation of SCs, and NGF and FGF levels were highest at a BDNF concentration of 50ng/mL. Compared with EAN group, SCs+BDNF group showed the lower paralysis scores from day 34 to day 45, and in sciatic nerves showed a significant decrease in inflammatory cell infiltration (involved CD4-, CD8- and CD68-positive cells) at days 25 and 35, an alleviated demyelination at days 35 and 45, and an increase in S-100-positive cells and a decrease in NGF-positive cells at each time point (P<0.05). Compared with the EAN group, the SCs+BDNF group showed, in sciatic nerves, the mRNA level of NGF was significantly decreased but that of S-100 was increased at day 25, the mRNA level of CCL3 was also remarkably reduced at day 35, and the mRNA level of CD11a, CCL3 and NGF was reduced but that of S-100 was elevated at day 45 (P<0.05). There were no differences in results between the SCs group and EAN group. In the end, we draw the conclusions that the exogenous SCs injected through cisterna magna can migrate to the injured peripheral nerves, BDNF promotes the proliferation and secretory function of SCs in vitro, and BDNF-treated SCs in vivo can reduce paralysis, inflammation, and demyelination and improve the self-repair capability of body in EAN.

Interleukin-10 gene-transfected mature dendritic cells suppress murine experimental autoimmune optic neuritis.

PURPOSE: We have reported that calcitonin gene-related peptide gene-transfected mature dendritic cells (mDC) suppress murine experimental autoimmune optic neuritis (EAON) and experimental autoimmune encephalitis (EAE) via interleukin-10 (IL-10) production. In our study, we examined whether IL-10-transfected mDC prevent development of EAON and EAE. METHODS: A plasmid expressing mouse IL-10 was constructed and used to transfect C57BL/6 mouse bone marrow-derived mDC by electroporation methods. C57BL/6 mice (with or without GFP expression) were immunized with myelo-oligodendrocyte glycoprotein35₋55 (MOG35₋55), and injected intravenously with IL-10-transfected mDC either in the induction or effector phase. RESULTS: When IL-10-transfected mDC were injected in the induction phase, EAE developed clinically in 60% of mice in the IL-10-transfected group compared to 100% in the mock-transfected group (P < 0.05), and mean pathologic score for EAON was 1.1 in the IL-10-transfected group compared to 2.1 in the mock-transfected group (P < 0.05). When IL-10-transfected mDC were injected in the effector phase, mean EAE clinical scores were not significantly different between the two groups (2.0 vs. 3.0), while the mean EAON pathologic score was lower in the IL-10-transfected group compared to the mock-transfected group (1.0 vs. 2.7, P < 0.05). Delayed hypersensitivity was suppressed significantly in the IL-10-transfected group. Interestingly, the proportions of CD80/86⁺ and MHC class II⁺ cells decreased significantly (P < 0.05), whereas Foxp3⁺ cells increased significantly in the spleen and lymph node in the IL-10-transfected group by flow cytometry analysis. Immunohistochemical analysis demonstrated the localization of IL-10-transfected GFP-expressing mDC not only in the spleen and lymph nodes but also in the inflamed optic nerve. CONCLUSIONS: Treatment with IL-10-expressing mDC was effective in suppressing the development of EAON and EAE.

Forced-exercise attenuates experimental autoimmune neuritis.

Physical inactivity in combination with a sedentary lifestyle is strongly associated with an increased risk of development of inflammatory-mediated diseases, including autoimmune disorders. Recent studies suggest that anti-inflammatory effects of physical exercise may be of therapeutic value in some affected individuals. In this study, we determined the effects of forced-exercise (treadmill running) on the development and progression of experimental autoimmune neuritis (EAN), an established animal model of Guillain-Barré syndrome. Adult male Lewis rats were subjected to sedentary (control) or forced-exercise (1.2 km per day, 5 days a week) for three weeks prior to induction of EAN. P2 (53-78)-immunized sedentary control rats developed a monophasic course of EAN beginning on post-injection day 12.33 ± 0.59 (n = 18) and reaching peak severity on day 15.83 ± 0.35 (n = 18). At near peak of disease, ankle- and sciatic notch-evoked compound muscle action potential (CMAP) amplitudes in sedentary control rats were reduced (~50%) while motor nerve conduction velocity (MNCV) was slowed (~30%) compared with pre-induction evoked responses. In marked contrast, rats undergoing forced-exercise exhibited a significantly less severe clinical course of EAN beginning on post-injection day 12.63 ± 0.53 (n = 16) and reaching peaking severity on day 14.69 ± 0.73 (n = 16). At near peak of disease, ankle- and sciatic-notch-evoked CMAP amplitudes in forced-exercised rats were preserved while EAN-associated slowing of MNCV was modestly attenuated by exercise. Three weeks of forced-exercise reduced by 46% total plasma corticosterone content while elevating the levels of corticosteroid binding globulin. We conclude from this study that forced-exercise administered prior to and during development of EAN affords a novel measure of protection against autoimmune-associated deficits in peripheral nerve evoked responses independent of steroid-induced immune suppression.

Mesenchymal stem cells lack efficacy in the treatment of experimental autoimmune neuritis despite in vitro inhibition of T-cell proliferation.

Mesenchymal stem cells have been demonstrated to ameliorate experimental autoimmune encephalomyelitis (EAE), a model of multiple sclerosis, prompting clinical trials in multiple sclerosis which are currently ongoing. An important question is whether this therapeutic effect generalises to other autoimmune neurological diseases. We performed two trials of efficacy of MSCs in experimental autoimmune neuritis (EAN) in Lewis (LEW/Han (M)Hsd) rats, a model of human autoimmune inflammatory neuropathies. No differences between the groups were found in clinical, histological or electrophysiological outcome measures. This was despite the ability of mesenchymal stem cells to inhibit proliferation of CD4+ T-cells in vitro. Therefore the efficacy of MSCs observed in autoimmune CNS demyelination models do not necessarily generalise to the treatment of other forms of neurological autoimmunity.

Inactivation of TLR9 by a suppressive oligodeoxynucleotides can ameliorate the clinical signs of EAN.

Susceptible-strain animals immunized with P2 peptide could generate the disease of experimental autoimmune neuritis (EAN) with inflammation and demyelination of peripheral nerve. A myriad of transcription factors and inflammatory cytokines have been found to participate in this process; however, the roles of toll-like receptors (TLRs) are poorly understood in EAN. The aim of this study is to explore the role of TLR9 in the pathogenesis of EAN. The EAN was induced in Lewis rat by immunization with P2(53-78) and complete Freund's adjuvant. CpG oligodeoxynucleotides (ODN) (cODN), a suppressive ODN (sODN) and a control non-specific ODN (nODN) were respectively administered to explore the role of TLR9 in EAN both in vivo and vitro. Following immunization up to the peak phase of EAN, EAN rats inoculated with sODN had remarkably better clinical score of EAN and expressed a significantly inhibited TLR9 signaling pathway. Our study suggests that TLR9 may be involved in the pathogenesis of EAN.

Analysis of the pathogenesis of experimental autoimmune optic neuritis.

Optic neuritis associated with multiple sclerosis has a strong association with organ-specific autoimmune disease. The goal of our research is to establish an optimal organ-specific animal model to elucidate the pathogenetic mechanisms of the disease and to develop therapeutic strategies using the model. This paper is divided into five sections: (1) clinical picture of optic neuritis associated with multiple sclerosis, (2) elucidation of pathogenesis using animal models with inflammation in optic nerve and spinal cord, (3) clinical relevance of concurrent encephalomyelitis in optic neuritis model, (4) retinal damage in a concurrent multiple sclerosis and optic neuritis model, and (5) development of novel therapies using mouse optic neuritis model. Advanced therapies using biologicals have succeeded to control intractable optic neuritis in animal models. This may ultimately lead to prevention of vision loss within a short period from acute onset of optic neuritis in human. By conducting research flexibly, ready to switch from the bench to the bedside and from the bedside to the bench as the opportunity arises, this strategy may help to guide the research of optic neuritis in the right direction.

The role of cytokines in Guillain-Barré syndrome.

Cytokines play an important role in the pathogenesis of autoimmune diseases including Guillain-Barré syndrome (GBS) and its animal model experimental autoimmune neuritis (EAN). In this article, we reviewed the current knowledge of the role of cytokines such as TNF-α, IFN-γ, IL-1ß, IL-6, IL-12, IL-18, IL-23, IL-17, IL-10, IL-4 and chemokines in GBS and EAN as unraveled by studies both in the clinic and the laboratory. However, these studies occasionally yield conflicting results, highlighting the complex role that cytokines play in the disease process. Efforts to modulate cytokine function in GBS and other autoimmune disease have shown efficiency indicating that cytokines are important therapeutic targets.

Novel anti-idiotype antibody therapy for lipooligosaccharide-induced experimental autoimmune neuritis: use relevant to Guillain-Barré syndrome.

Campylobacteriosis is a frequent antecedent event in Guillain-Barré syndrome (GBS), inducing high-titer serum antibodies for ganglioside antigens in the peripheral nervous system (PNS). Molecular mimicry between the lipooligosaccharide (LOS) component of Campylobacter jejuni and human peripheral nerve gangliosides is believed to play an important role in the pathogenesis of GBS. Conventional treatment strategies for patients with GBS include plasmapheresis, intravenous immunoglobulin (IVIG), and immunosuppression, which are invasive or relatively ineffective. In this study, we used our animal model of GBS, in which Lewis rats were immunized with GD3-like LOS isolated from C.jejuni. The animals developed anti-GD3 ganglioside antibodies and manifested neuromuscular dysfunction. To develop novel therapeutic strategies, we treated the animals by intraperitoneal administration of an anti-GD3 antiidiotype monoclonal antibody (BEC2) that specifically interacts with the pathogenic antibody. The treated animals had a remarkable reduction of anti-GD3 antibody titers and improvement of motor nerve functions. The results suggest that ganglioside mimics, such as antiidiotype antibodies, may be powerful reagents for therapeutic intervention in GBS by neutralizing specific pathogenic antiganglioside antibodies.

[Study on therapy of experimental autoimmune neuritis by bone marrow stromal cells].

AIM: To investigate the therapeutic effect of bone marrow stromal cells (BMSCs) transplantation on experimental autoimmune neuritis (EAN) and study the possible mechanism. METHODS: EAN model was established by immunizing Lewis rats with P(0)180-199 peptide and complete Freund's adjuvant (CFA). In the therapy group, BMSCs (2x10(6) cells/rat) were marked with fluorochrome PKH26 and injected into the rats' caudal vein 10 d after immunization. The therapeutic effect of BMSC transplantation on EAN rats was investigated by clinical assessment, immunohistochemical staining, and ELISA, respectively. RESULTS: The injected BMSCs could migrate to the demyelinated nerve tissues, and the demyelination and inflammatory infiltration was relieved. The infiltration of CD4(+) and CD8(+) T cells and the sera level of IFN-gamma and TNF-alpha were decreased significantly (P<0.05), whereas IL-4 level in the supernatant of cultured lymphocytes was increased (P<0.05). CONCLUSION: Certain therapeutic effect of BMSC transplantation on EAN was observed. BMSCs could reverse the disbalance of Th1/Th2 cells by regulating the cytokine expression and could inhibit the activation and proliferation of T cells.

Macrophage migration inhibitory factor (MIF) seems crucially involved in Guillain-Barré syndrome and experimental allergic neuritis.

Macrophage migration inhibitory factor (MIF) is a proinflammatory type 1 cytokine that plays a pathogenic role in several inflammatory and autoimmune diseases. The role of this cytokine in peripheral nerve inflammatory disease has not been evaluated. Therefore, to evaluate the role of macrophage migration inhibitory factor (MIF) in Guillain-Barré syndrome (GBS) and experimental allergic neuritis (EAN), we determined MIF circulating levels in a series of patients with GBS and healthy subjects with ELISA and evaluated the effect of two specific inhibitors of MIF, a neutralizing monoclonal antibody or a chemical inhibitor ISO1 on the course of murine EAN. The data show increased MIF plasma levels in GBS patients as compared to healthy controls (p<0.0001) and a progressive increase of MIF circulating concentration with patient's disability (p<0.0001). Both anti-MIF mAb and ISO1 favorably influenced the course of EAN. Treated mice had a lower cumulative severity score (p=0.001) and reduced disease duration than the control mice (p<0.03). MIF may promote immune reaction in GBS. Therapeutic effects of both anti-MIF mAb and ISO1 in EAN suggest that MIF could be a promising therapeutic target in inflammatory demyelinating peripheral nerve disorders.

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.