Protective effects of carbonyl iron against multiple low-dose streptozotocin-induced diabetes in rodents.

Particulate adjuvants have shown increasing promise as effective, safe, and durable agents for the stimulation of immunity, or alternatively, the suppression of autoimmunity. Here we examined the potential of the adjuvant carbonyl iron (CI) for the modulation of organ-specific autoimmune disease-type 1 diabetes (T1D). T1D was induced by multiple low doses of streptozotocin (MLDS) that initiates beta cell death and triggers immune cell infiltration into the pancreatic islets. The results of this study indicate that the single in vivo application of CI to MLDS-treated DA rats, CBA/H mice, or C57BL/6 mice successfully counteracted the development of insulitis and hyperglycemia. The protective action was obtained either when CI was applied 7 days before, simultaneously with the first dose of streptozotocin, or 1 day after MLDS treatment. Ex vivo cell analysis of C57BL/6 mice showed that CI treatment reduced the proportion of proinflammatory F4/80+ CD40+ M1 macrophages and activated T lymphocytes in the spleen. Moreover, the treatment down-regulated the number of inflammatory CD4+ IFN-γ+ cells in pancreatic lymph nodes, Peyer's patches, and pancreas-infiltrating mononuclear cells, while simultaneously potentiating proportion of CD4+ IL17+ cells. The regulatory arm of the immune system represented by CD3+ NK1.1+ (NKT) and CD4+ CD25+ FoxP3+ regulatory T cells was potentiated after CI treatment. In vitro analysis showed that CI down-regulated CD40 and CD80 expression on dendritic cells thus probably interfering with their antigen-presenting ability. In conclusion, particulate adjuvant CI seems to suppress the activation of the innate immune response, which further affects the adaptive immune response directed toward pancreatic beta cells.

A comparative analysis of multiple sclerosis-relevant anti-inflammatory properties of ethyl pyruvate and dimethyl fumarate.

Dimethyl fumarate (DMF), a new drug for multiple sclerosis (MS) treatment, acts against neuroinflammation via mechanisms that are triggered by adduct formation with thiol redox switches. Ethyl pyruvate (EP), an off-the-shelf agent, appears to be a redox analog of DMF, but its immunomodulatory properties have not been put into the context of MS therapy. In this article, we examined and compared the effects of EP and DMF on MS-relevant activity/functions of T cells, macrophages, microglia, and astrocytes. EP efficiently suppressed the release of MS signature cytokines, IFN-γ and IL-17, from human PBMCs. Furthermore, the production of these cytokines was notably decreased in encephalitogenic T cells after in vivo application of EP to rats. Production of two other proinflammatory cytokines, IL-6 and TNF, and NO was suppressed by EP in macrophages and microglia. Reactive oxygen species production in macrophages, microglia activation, and the development of Ag-presenting phenotype in microglia and macrophages were constrained by EP. The release of IL-6 was reduced in astrocytes. Finally, EP inhibited the activation of transcription factor NF-κB in microglia and astrocytes. Most of these effects were also found for DMF, implying that EP and DMF share common targets and mechanisms of action. Importantly, EP had in vivo impact on experimental autoimmune encephalomyelitis, an animal model of MS. Treatment with EP resulted in delay and shortening of the first relapse, and lower clinical scores, whereas the second attack was annihilated. Further studies on the possibility to use EP as an MS therapeutic are warranted.

Severe combined immunodeficiency in Serbia and Montenegro between years 1986 and 2010: a single-center experience.

Severe combined immunodeficiency (SCID), including the 'variant' Omenn syndrome (OS), represent a heterogeneous group of monogenic disorders characterized by defect in differentiation of T- and/or B lymphocytes and susceptibility to infections since birth. In the period of 25 years, between January 1986 and December 2010, a total of 21 patients (15 SCID, 6 OS) were diagnosed in Mother & Child Health Institute of Serbia, a tertiary-care teaching University hospital and a national referral center for patients affected with primary immunodeficiency (PID). The diagnoses were based on anamnestic data, clinical findings, and immunological and genetic analysis. The median age at the onset of the first infection was the 2nd month of life. Seven (33 %) patients had positive family history for SCID. Out of five male infants with T-B+NK- SCID phenotype, mutation analysis revealed interleukin-2 (common) gamma-chain receptor (IL2RG) mutations in 3 with positive X-linked family history, and Janus-kinase (JAK)-3 gene defects in the other two. Six patients had T-B-NK+ SCID phenotype and further 6 features of OS, 11 of which had recombinase-activating gene (RAG1or RAG2) and 1 Artemis gene mutations. One child with T+B+NK+ SCID phenotype as well had proven RAG mutation. One child each with T-B+NK+ SCID phenotype, CD8 lymphopenia and unknown phenotype remained without known underlying genetic defect. Of the eight patients who underwent hematopoetic stem cell transplant (HSCT) 5 survived, the other 13 died between 2 days and 12 months after diagnosis was made. Early diagnosis of SCID, before onset of severe infections, offers possibility for HSCT and cure. Education of primary-care pediatricians, in particular including awareness of the risk of using live vaccines and non-irradiated blood products, should improve prognosis of SCID in our setting.

Nitric oxide inhibits CXCL12 expression in neuroinflammation.

Chemokine CXCL12 (C-X-C motif chemokine ligand 12) restricts immune cell invasion of the central nervous system (CNS) and limits neuroinflammation in experimental autoimmune encephalomyelitis (EAE), an animal model of inflammatory and demyelinating disease of the CNS, multiple sclerosis (MS). Nitric oxide (NO), by contrast, predominantly contributes to CNS tissue destruction in MS and EAE. Thus, the influence of NO on CXCL12 in the inflamed CNS was investigated. Excess expression of inducible NO synthase was inversely correlated to CXCL12 gene expression in spinal cord homogenates of rats immunized to develop EAE. NO inhibited gene expression of CXCL12 in astrocytes and endothelial cells in vitro. The inhibition was paralleled with reduction of p38 mitogen-activated protein kinase (MAPK) phosphorylation and it was mimicked with inhibitors of p38 MAPK activation in astrocytes. In vivo suppression of nitric generation recovered CXCL12 expression in the CNS and attenuated EAE in Dark Agouti rats. On the contrary, in vivo NO donation decreased CXCL12 expression in the CNS of EAE-resistant Albino Oxford (AO) rats. However, the effect was not paralleled with induction of EAE in AO rats. It is suggested that NO acting through suppression of p38 MAPK inhibits CXCL12 expression in neuroinflammation. These results imply that downregulation of NO release and protection of CXCL12 expression within the CNS might present the potential approaches in MS therapy.

Betulinic acid regulates generation of neuroinflammatory mediators responsible for tissue destruction in multiple sclerosis in vitro.

AIM: To investigate the influences of betulinic acid (BA), a triterpenoid isolated from birch bark, on neuroinflammatory mediators involved in the pathogenesis of multiple sclerosis and experimental autoimmune encephalomyelitis in vitro. METHODS: Encephalitogenic T cells were prepared from draining lymph nodes and spinal cords of Dark Agouti rats 8 to 10 d after immunization with myelin basic protein (MBP) and complete Freund's adjuvant. Macrophages were isolated from the peritoneal cavity of adult untreated rats. Astrocytes were isolated from neonatal rat brains. The cells were cultured and then treated with different agents. IFN-γ, IL-17, iNOS and CXCL12 mRNA levels in the cells were analyzed with RT-PCR. iNOS and CXCL12 protein levels were detected using immunoblot. NO and ROS generation was measured using Griess reaction and flow cytometry, respectively. RESULTS: In encephalitogenic T cells stimulated with MBP (10 µg/mL), addition of BA inhibited IL-17 and IFN-γ production in a dose-dependent manner. The estimated IC(50) values for IL-17 and IFN γ were 11.2 and 63.8 µmol/L, respectively. When the macrophages were stimulated with LPS (10 ng/mL), addition of BA (50 µmol/L) significantly increased ROS generation, and suppressed NO generation. The astrocytes were stimulated with ConASn containing numerous inflammatory mediators, which mimicked the inflammatory milieu within CNS; addition of BA (50 µmol/L) significantly increased ROS generation, and blocked ConASn-induced increases in iNOS and CXCL12 mRNA levels, but did not affect iNOS and CXCL12 protein levels. Importantly, in both the macrophages and astrocytes, addition of BA (50 µmol/L) inhibited lipid peroxidation. CONCLUSION: Besides inhibiting encephalitogenic T cell cytokines and reducing NO generation, BA induces tissue-damaging ROS generation within CNS.

Trichinella spiralis shares epitopes with human autoantigens.

Like other helminths, Trichinella spiralis has evolved strategies to allow it to survive in the host organism, including the expression of epitopes similar to those present in either expressed or hidden host antigens. To identify T. spiralis-derived antigens that are evolutionarily conserved in the parasite and its host and that could be responsible for its evasion of the host immune response, we examined the reactivity of six different types of autoantibodies to T. spiralis larvae from muscle. T. spiralis antigens that share epitopes with human autoantigens were identified by assessing the cross-reactivity of autoantibody-containing serum samples with T. spiralis antigens in the absence of specific anti-parasite antibodies. Of the 55 autoantibody-containing human serum samples that we analysed by immunohistological screening, 24 (43.6%) recognised T. spiralis muscle larvae structures such as the subcuticular region, the genital primordium or the midgut. Using Western blots, we demonstrated that the same sera reacted with 24 protein components of T. spiralis muscle larvae excretory-secretory L1 antigens. We found that the human autoantibodies predominantly bound antigens belonging to the TSL1 group; more specifically, the autoantibody-containing sera reacted most frequently with the 53-kDa component. Thus, this protein is a good candidate for further studies of the mechanisms of T. spiralis-mediated immunomodulation.

It is still not for the old iron: adjuvant effects of carbonyl iron in experimental autoimmune encephalomyelitis induction.

Experimental autoimmune encephalomyelitis (EAE) is a model of multiple sclerosis. Dark Agouti rats immunized with spinal cord homogenate (SCH) and carbonyl iron (CI), as an adjuvant, develop severe hyperacute form of EAE. They succumb to EAE earlier and have higher clinical scores and lethality rate in comparison to counterparts immunized with SCH + complete Freund's adjuvant. There is no difference in the number of cells or in histological presentation of the CNS infiltrates of rats immunized with the two adjuvants. However, there are more granulocytes, NK and NKT cells, and less CD4(+) T cells in the spinal cord infiltrates of SCH + CI-immunized animals. Nitric oxide (NO)-generating enzyme inducible NO synthase have higher expression in spinal cord of SCH + CI-immunized rats, and this corresponds to more intensive nitrotyrosine formation in the CNS tissue of these rats. Abundant infiltration of granulocytes and NK cells into the CNS and excessive generation of peroxynitrite within the CNS of SCH + CI-immunized rats might account for the severe neurological deficits induced by immunization with CI. These factors should be closely examined in the fulminant forms of multiple sclerosis and acute disseminated encephalomyelitis, as they could represent a promising targets for therapy.

Complete Freund's adjuvant-free experimental autoimmune encephalomyelitis in Dark Agouti rats is a valuable tool for multiple sclerosis studies.

Experimental autoimmune encephalomyelitis (EAE) is classically induced with complete Freund's adjuvant (CFA). The immune response against CFA has a confounding influence on the translational capacity of EAE as a multiple sclerosis model. Here, we compare clinical, cellular and molecular properties between syngeneic spinal cord homogenate (SCH)- and SCH + CFA-immunized Dark Agouti rats. EAE signs were observed earlier and the cumulative clinical score was higher without CFA. Also, a higher number of immune cells infiltrates in the spinal cords was noticed at the peak of EAE without CFA. High spinal cord abundance of CD8+CD11bc+MHC class II+ cells was detected in SCH-immunized rats. Myelin basic protein -specific response can be elicited in the cells from the lymph nodes draining the site of SCH immunization. This CFA-free EAE is a reliable multiple sclerosis model.

Methylprednisolone inhibits IFN-gamma and IL-17 expression and production by cells infiltrating central nervous system in experimental autoimmune encephalomyelitis.

BACKGROUND: Glucocorticoids have been shown to be effective in the treatment of autoimmune diseases of the CNS such as multiple sclerosis and its animal model, experimental autoimmune encephalomyelitis (EAE). However, the mechanisms and the site of glucocorticoids' actions are still not completely defined. The aim of this study was to investigate the in vivo effect of the synthetic glucocorticoid methylprednisolone (MP) on the expression and production of proinflammatory cytokines interferon (IFN)-gamma and interleukin (IL)-17 by cells infiltrating CNS tissue. METHODS: Experimental autoimmune encephalomyelitis was induced in Dark Agouti (DA) rats by immunization with rat spinal cord homogenate mixed with adjuvants. Commencing on the day when the first EAE signs appeared, DA rats were injected daily for 3 days with MP and/or RU486, an antagonist of glucocorticoid receptor. Cytokine production and gene expression in CNS-infiltrating cells and lymph node cells were measured using ELISA and real time PCR, respectively. RESULTS: Treatment of rats with MP ameliorated EAE, and the animals recovered without relapses. Further, MP inhibited IFN-gamma and IL-17 expression and production in cells isolated from the CNS of DA rats with EAE after the last injection of MP. The observed effect of MP in vivo treatment was not mediated through depletion of CD4+ T cells among CNS infiltrating cells, or through induction of their apoptosis within the CNS. Finally, the glucocorticoid receptor-antagonist RU486 prevented the inhibitory effect of MP on IFN-gamma and IL-17 production both in vitro and in vivo, thus indicating that the observed effects of MP were mediated through glucocorticoid receptor-dependent mechanisms. CONCLUSION: Taken together, these results demonstrate that amelioration of EAE by exogenous glucocorticoids might be, at least partly, ascribed to the limitation of effector cell functions in the target tissue.

Cerebrospinal fluid and serum uric acid levels in patients with multiple sclerosis.

BACKGROUND: Peroxynitrite was hypothesized to be involved in the pathogenesis of multiple sclerosis (MS) through its various neurotoxic effects. Uric acid (UA) was shown to be a strong peroxynitrite scavenger. METHODS: We analyzed cerebrospinal fluid (CSF) and serum UA concentrations in 30 MS patients and 20 controls with non-inflammatory neurological diseases (NIND) and correlated these findings with demographic and clinical characteristics of MS patients. Disease activity was assessed by brain magnetic resonance imaging (MRI) and the CSF/serum albumin quotient as an indicator of the state of blood-brain-barrier (BBB). RESULTS: Serum UA concentrations were found to be significantly lower in MS patients compared with controls (p=0.019). CSF UA concentrations were lower in MS patients as compared to controls, as well as in patients with active MS (clinical and/or MRI activity) in comparison to patients with inactive MS or controls, but these differences were not statistically significant. Significant correlation was found between CSF and serum UA concentrations (p=0.016) in MS patients, but not in controls; and between CSF UA concentrations and the CSF/serum albumin quotient in MS patients (p=0.043), but not in controls. CONCLUSIONS: Our results support the significance of UA in the pathogenesis of MS. Decreased serum UA concentrations in MS patients might be due to both intrinsically reduced antioxidant capacity and increased UA consumption in MS. CSF UA concentrations may not be a reliable marker of disease activity in MS since its concentration is dependent on leakage of UA molecules from serum through the damaged BBB and the balance between consumption/production within the central nervous system (CNS).

Transforming growth factor-beta 1 in Balkan endemic nephropathy.

BACKGROUND/AIM: The aim of this study was to compare plasma and urine transforming growth factor-beta1 (TGF-beta1) levels in patients with different stages of Balkan endemic nephropathy (BEN) with those in patients with primary glomerulonephritis (GN) and healthy controls. METHODS: The study involved 47 patients with BEN (30 with manifest BEN and 17 in the early stage of BEN), 12 patients with GN and 10 healthy controls. Plasma and urine TGF-beta1 was assayed by enzyme-linked immunosorbent assay. RESULTS: The median plasma TGF-beta1 levels differed nonsignificantly between the groups (4,908-6,442 pg/ml), but individual plasma TGF-beta1 levels in BEN patients exhibited the highest dispersion. Median urinary TGF-beta1 excretion (pg/mg creatinine) was significantly higher in patient groups (manifest BEN: 203, early-stage BEN: 341, GN: 775) than in healthy controls (42). No correlation was found between plasma and urine TGF-beta1 levels or between plasma TGF-beta1 levels and creatinine clearance for any of the examined groups. CONCLUSION: Plasma TGF-beta1 levels in BEN patients extended over the widest range, but no significant differences were found between the median values for the groups. Median urinary TGF-beta1 excretion was significantly higher in patients with BEN and GN than in healthy controls.

Ribavirin administration alters ectonucleotidase activities in experimental autoimmune encephalomyelitis.

The role of extracellular purines and purinoreceptors in the pathophysiology of different neurological disorders is the focus of rapidly expanding area of research. Ectonucleotidases are the enzymes with multiple roles in extracellular nucleotides metabolism and regulation of nucleotidebased intercellular signaling. The aim of present study was to investigate the changes in the ATP, ADP and AMP hydrolyzing activities after ribavirin treatment in spinal cord during experimental autoimmune encephalomyelitis (EAE). Our results demonstrate that ribavirin itself had no significant effect on ectoenzyme activities, when tested in vitro and in vivo on spinal cord crude membrane preparation of intact animals. We observed significant increase in ATP, ADP and AMP hydrolyzing activity in the spinal cord crude membrane preparation in EAE animals at 15 days post immunization compared to control animals. The increase was registered at 28 days post immunization, as well. At same time points, ribavirin treatment decreased ATP, ADP and AMP hydrolyzing activity compared to EAE animals. In addition, no significant changes 8 days post immunization was observed between EAE-induced and ribavirin- treated EAE animals and these levels were similar to control level. Thus, we suppose that ribavirin-induced alteration in ectonucleotidase activities is rather due to its suppression of inflammation, than to its direct action on ATP, ADP and AMP hydrolysis.

Oral neonatal antibiotic treatment perturbs gut microbiota and aggravates central nervous system autoimmunity in Dark Agouti rats.

Gut microbiota dysbiosis has been considered the essential element in the pathogenesis of multiple sclerosis and its animal model, experimental autoimmune encephalomyelitis (EAE). Antibiotics were administered orally to Dark Agouti (DA) rats early in their life with the aim of perturbing gut microbiota and investigating the effects of such intervention on the course of EAE. As a result, the diversity of the gut microbiota was reduced under the influence of antibiotics. Mainly, Firmicutes and Actinobacteria were replaced by Proteobacteria and Bacteroidetes, while decreased proportions of Clostridia and Bacilli classes were accompanied by an increase in Gamma-Proteobacteria in antibiotic-treated animals. Interestingly, a notable decrease in the Helicobacteraceae, Spirochaetaceae and Turicibacteriaceae was scored in antibiotic-treated groups. Also, levels of short chain fatty acids were reduced in the faeces of antibiotic-treated rats. Consequently, aggravation of EAE, paralleled with stronger immune response in lymph nodes draining the site of immunization, and increased inflammation within the CNS, were observed in antibiotic-treated DA rats. Thus, the alteration of gut microbiota leads to an escalation of CNS-directed autoimmunity in DA rats. The results of this study indicate that antibiotic use in early life may have subsequent unfavourable effects on the regulation of the immune system.

Comparison of dendritic cells obtained from autoimmunty-prone and resistant rats.

Dendritic cells (DC) are responsible for the initiation and shaping of the adaptive immune response and are in the focus of autoimmunity research. We were interested in comparison of DC obtained from autoimmunity-prone Dark Agouti (DA) rats and autoimmunity-resistant Albino Oxford (AO) rats. DC were generated from bone marrow precursors and matured (mDC) by lipopolysaccharide. Tolerogenic DC (tolDC) obtained by vitamin D3 treatment were studied in parallel. Profile of cytokine production was different in AO and DA mDC and tolDC. Expression of MHC class II molecules and CD86 were higher in DA DC, while vitamin D3 reduced their expression in dendritic cells of both strains. Allogeneic proliferation of CD4+ T cells was reduced by AO tolDC, but not with DA tolDC in comparison to respective mDC. Finally, expression of various genes identified as differentially expressed in human mDC and tolDC was also analyzed in AO and DA DC. Again, AO and DA DC differed in the expression of the analyzed genes. To conclude, AO and DA DC differ in production of cytokines, expression of antigen presentation-related molecules and in regulation of CD4+ T proliferation. The difference is valuable for understanding the divergence of the strains in their susceptibility to autoimmunity.

Methylprednisolone inhibits interleukin-17 and interferon-gamma expression by both naive and primed T cells.

BACKGROUND: Interleukin-17 (IL-17)-producing cells are increasingly considered to be the major pathogenic population in various autoimmune disorders. The effects of glucocorticoids, widely used as therapeutics for inflammatory and autoimmune disorders, on IL-17 generation have not been thoroughly investigated so far. Therefore, we have explored the influence of methylprednisolone (MP) on IL-17 expression in rat lymphocytes, and compared it to the effect of the drug on interferon (IFN)-gamma. RESULTS: Production of IL-17 in mitogen-stimulated lymph node cells (LNC) from non-treated rats, as well as in myelin basic protein (MBP)-stimulated draining LNC from rats immunized with spinal cord homogenate and complete Freund's adjuvant was significantly reduced by MP. The reduction was dose-dependent, sustained through the follow-up period of 48 hours, and was not achieved through anti-proliferative effect. Additionally, MP inhibited IL-17 production in purified T cells as well, but to less extent than in LNC. In its influence on IL-17 production MP inhibited Ror-gammaT transcription factor expression, as well as Jun phosphorylation, but not ERK or p38 activation in mitogen-stimulated LNC. Importantly, MP collaborated with IFN-gamma in inhibiting IL-17 generation in LNC. CONCLUSION: The observed difference in the effect of MP on IL-17 and IFN-gamma could be important for the understanding of the variability in the efficiency of glucocorticoids in the treatment of autoimmune diseases.

Kinetics of IFN-gamma and IL-17 expression and production in active experimental autoimmune encephalomyelitis in Dark Agouti rats.

Interferon-gamma (IFN-gamma) and interleukin-17 (IL-17) have been involved in the pathogenesis of experimental autoimmune encephalomyelitis (EAE). We have carried out a follow-up study of the expression and production of these cytokines, as well as of cells expressing these cytokines during the course of active EAE in Dark Agouti (DA) rats. As a result, IL-17, but not IFN-gamma expression and production had the peak value in draining lymph nodes (DLN) during the induction phase of the disease, and in spinal cords (SC) at the onset of clinical signs of the disease, and then declined toward the resolution of the disease. Also, a significant proportion of IFN-gamma/IL-17 double-positive cells was observed in SC of DA rats in active EAE. Importantly, the highest proportion of IL-17 single positive and double-positive cells, but not of IFN-gamma single positive cells, was observed at the onset of the disease. The observed difference in the kinetics of IFN-gamma and IL-17 expression during active EAE in DA rats suggests different roles these cytokines might have in the pathogenesis of the disease.

Therapeutic effects of combined treatment with ribavirin and tiazofurin on experimental autoimmune encephalomyelitis development: clinical and histopathological evaluation.

Experimental autoimmune encephalomyelitis (EAE) is an animal model of multiple sclerosis (MS) and the helpful tool in preclinical testing of various substances considered for treatment of this human CNS disease. Ribavirin (R) and tiazofurin (T) are purine nucleoside analogues, with the broad spectrum of anti-viral, anti-tumoral and anti-inflammatory properties. We proposed that combined treatment with RT, administrated during the effector phase of EAE, would attenuate disease severity, both clinically and pathologically. Ribavirin was given daily at a dosage of 30 mg/kg and tiazofurin was given at a dosage of 10 mg/kg every other day for 15 days. We detected amelioration of clinical signs and faster recovery in the RT group compared to the control group. Immunohistochemical analyses revealed that RT treatment decrease the number of T cells, macrophages and microglia. In the controls, we detected reactive type of microglia, while in the RT group we noticed ramified/resting form. Demyelination areas and axonal damage were not recorded in the RT group, in contrast to the control group where multiple areas of demyelination zones and axonal loss were found. RT combination treatment suppresses ongoing EAE, prevents demyelination and axonal loss, and therefore may well be the potential therapy for the treatment of MS.

Ribavirin ameliorates experimental autoimmune encephalomyelitis in rats and modulates cytokine production.

To determine the mechanism underlying ribavirin induced amelioration of experimental autoimmune encephalomyelitis (EAE), cytokine profiles were evaluated in draining lymph node (DLN) cell culture supernatants and spinal cord obtained from EAE and/or ribavirin-treated EAE Dark Agouti rats. Administration of ribavirin to EAE rats markedly affected the production of pro-inflammatory cytokines IFN-gamma, IL-1beta and TNF-alpha in DLN and spinal cord, thus shifting the balance towards the anti-inflammatory cytokines IL-10 and TGF-beta. These findings suggest that ribavirin attenuates EAE by limiting cytokine-mediated immunoinflammatory events leading to CNS destruction. The conducted experiments provide rationale for ribavirin to be considered as a candidate drug in the development of new therapeutic strategies for the treatment of autoimmune diseases in humans, such as multiple sclerosis.

Gut Microbiota Confers Resistance of Albino Oxford Rats to the Induction of Experimental Autoimmune Encephalomyelitis.

Albino Oxford (AO) rats are extremely resistant to induction of experimental autoimmune encephalomyelitis (EAE). EAE is an animal model of multiple sclerosis, a chronic inflammatory disease of the central nervous system (CNS), with established autoimmune pathogenesis. The autoimmune response against the antigens of the CNS is initiated in the peripheral lymphoid tissues after immunization of AO rats with CNS antigens. Subsequently, limited infiltration of the CNS occurs, yet without clinical sequels. It has recently become increasingly appreciated that gut-associated lymphoid tissues (GALT) and gut microbiota play an important role in regulation and propagation of encephalitogenic immune response. Therefore, modulation of AO gut microbiota by antibiotics was performed in this study. The treatment altered composition of gut microbiota in AO rats and led to a reduction in the proportion of regulatory T cells in Peyer's patches, mesenteric lymph nodes, and in lymph nodes draining the site of immunization. Upregulation of interferon-γ and interleukin (IL)-17 production was observed in the draining lymph nodes. The treatment led to clinically manifested EAE in AO rats with more numerous infiltrates and higher production of IL-17 observed in the CNS. Importantly, transfer of AO gut microbiota into EAE-prone Dark Agouti rats ameliorated the disease. These results clearly imply that gut microbiota is an important factor in AO rat resistance to EAE and that gut microbiota transfer is an efficacious way to treat CNS autoimmunity. These findings also support the idea that gut microbiota modulation has a potential as a future treatment of multiple sclerosis.

Correlation of Gut Microbiota Composition with Resistance to Experimental Autoimmune Encephalomyelitis in Rats.

Multiple sclerosis is a chronic inflammatory disease of the central nervous system (CNS). It is widely accepted that autoimmune response against the antigens of the CNS is the essential pathogenic force in the disease. It has recently become increasingly appreciated that activated encephalitogenic cells tend to migrate toward gut associated lymphoid tissues (GALTs) and that interrupted balance between regulatory and inflammatory immunity within the GALT might have decisive role in the initiation and propagation of the CNS autoimmunity. Gut microbiota composition and function has the major impact on the balance in the GALT. Thus, our aim was to perform analyses of gut microbiota in experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis. Albino Oxford (AO) rats that are highly resistant to EAE induction and Dark Agouti (DA) rats that develop EAE after mild immunization were compared for gut microbiota composition in different phases after EAE induction. Microbial analyses of the genus Lactobacillus and related lactic acid bacteria showed higher diversity of Lactobacillus spp. in EAE-resistant AO rats, while some members of Firmicutes and Proteobacteria (Undibacterium oligocarboniphilum) were detected only in feces of DA rats at the peak of the disease (between 13 and 16 days after induction). Interestingly, in contrast to our previous study where Turicibacter sp. was found exclusively in non-immunized AO, but not in DA rats, in this study it was detected in DA rats that remained healthy 16 days after induction, as well as in four of 12 DA rats at the peak of the disease. Similar observation was obtained for the members of Lachnospiraceae. Further, production of a typical regulatory cytokine interleukin-10 was compared in GALT cells of AO and DA rats, and higher production was observed in DA rats. Our data contribute to the idea that gut microbiota and GALT considerably influence multiple sclerosis pathogenesis.