The Therapeutic Effect of Vasoactive Intestinal Peptide on Experimental Arthritis is Associated with CD4+CD25+ T Regulatory Cells

Vasoactive intestinal peptide (VIP) has been found to act as a potent anti-inflammatory factor through regulating the production of both anti- and pro-inflammatory mediators and promoting Th2-type responses. In this study, we used Chicken collagen II-induced experimental arthritis (CIA) model in Wistar rats to investigate the potential effects of VIP on rheumatoid arthritis. Our results showed that in vivo treatment of CIA-induced rats with VIP had great protective benefit at both clinical and histological levels. Disease suppression was associated with the inhibition of T cells proliferation, shifting of the immune response toward a Th2-type response and expanded CD4⁺CD25⁺ Treg in the periphery, which inhibited autoreactive T cell activation/expansion. In conclusion, the study provides evidence that VIP had great protective effect on CIA through its inhibition actions on pathogenic T cells.     

IL-15-secreting γδT cells induce memory T cells in experimental allergic encephalomyelitis (EAE) mice

With the most recent data suggesting γδT cells as primary producers of the pro-inflammatory autoimmune-associated cytokine, the relationship between γδT cells and Th17 in experimental allergic encephalitis (EAE) mice requires more extensive investigation. By flow cytometry and qPCR, we identified a new subset of IL-15-secreting γδT (γδT15) cells that increased in EAE mice. The capacity of IL-15-secreting γδT cells inducing memory T cells and memory T cells inducing IL-17⁺Th17 was examined by transferring into EAE mice and 7-week-old female nude mice, respectively. We found that γδT15 induced CD44^hi memory T cells by secreting IL-15. γδT15-induced memory T cells induced EAE by transforming into pathogenic Th17 cells. The data suggest that a new subset of IL-15-secreting γδT cells mediated the production of memory T cells which transformed into pathogenic Th17 cells in EAE mice.     

Do Th2 cells mediate the effects of glatiramer acetate in experimental autoimmune encephalomyelitis?

Mechanisms underlying the clinical benefits of glatiramer acetate (GA) for patients with multiple sclerosis (MS) remain elusive. A prevailing hypothesis is that GA can induce Th2-polarized T cells, which cross-recognize myelin-specific epitopes and can inhibit myelin-reactive autoaggression in Th1 T cells, a process referred to as 'bystander suppression.' To test whether the efficacy of GA is indeed mediated by Th2 T cells, we have utilized an animal model for MS: experimental autoimmune encephalomyelitis (EAE) in C57BL/6 mice. GA therapy conferred moderate protection from EAE. GA-reactive T cells from these mice were not Th2 polarized, and the Th1 cytokine reduction of myelin-reactive T cells in GA-treated mice was comparable to that in untreated control mice. Significantly, the protective effects of GA against EAE were also observed in IL-4-, IL-10-deficient and IL-4/IL-10 double-deficient mice. Similar to wild-type mice, GA therapy in IL-4- and IL-10-deficient mice was associated with diminished myelin-reactive T cell expansion and reduced production of myelin antigen-induced IFN-gamma and tumor necrosis factor-alpha. Thus, despite the absence of two prominent Th2 cytokines, IL-4 and IL-10, either alone or combined, GA was still beneficial in suppressing EAE. Our results caution against the notion that Th2 cells and bystander suppression account for the effect of GA on EAE and suggest that an alternative mechanism may operate in GA-treated MS patients.     

Experimental autoimmune encephalomyelitis can be prevented and cured by infection with Trypanosoma cruzi

Trypanosoma cruzi is an intracellular parasite that induces a strong Th1-type response and immunosuppression during the acute phase of infection. To study how the infection with T. cruzi would modulate the development of an autoimmune disease, we immunized C57BL/6 mice and IL-10 or iNOS knock-out mice of the same background with the encephalitogenic MOG 35-55 peptide and infected them with T. cruzi. Our results demonstrate that infection with T. cruzi completely prevents EAE development and furthermore induces complete and lasting remission in mice that were infected with this parasite after they had developed clinical EAE. Nitric oxide and IL-10 participate in triggering the mechanisms associated with EAE suppression by the infection. Decreased lymphoproliferation and increased frequencies of Annexin-positive cells and of T cells bearing CD95, CD95L or CTLA-4 were observed in the spleen from immunized/infected mice, as well as lower IL-2 and increased TGF-beta production in comparison with only immunized mice. Our results indicate that several effector and regulatory mechanisms of the immune response that arise during the acute phase of T. cruzi infection lastingly affect the expansion and/or effector functions of encephalitogenic cells, preventing the onset or inducing complete remission of EAE.     

COX-2 Inhibitors Modulate IL-12 Signaling Through JAK-STAT Pathway Leading to Th1 Response in Experimental Allergic Encephalomyelitis

Experimental allergic encephalomyelitis (EAE) is a Th1 cell-mediated autoimmune disease model of multiple sclerosis (MS). IL-12 plays a crucial role in the pathogenesis of EAE/MS and inhibition of IL-12 production or IL-12 signaling was effective in preventing EAE. Cyclooxygenase (COX-2) is a key enzyme promoting inflammation in rheumatoid arthritis and tumor induced angiogenesis. Recent studies have shown that COX-2 inhibitors prevent EAE, however, their mechanism of action is not fully understood. In this study, we show that in vivo treatment (i.p.) with 100 μg COX-2 selective inhibitors (LM01, LM08, LM11, and NS398), on every other day from day 0 to 30, significantly reduced the incidence and severity of EAE in SJL/J and C57BL/6 mice. Further analyses showed that the COX-2 inhibitors reduced neural antigen-induced IL-12 production, T cell proliferation and Th1 differentiation ex vivo and in vitro. The COX-2 inhibitors also decreased IL-12-induced T cell responses through blocking tyrosine phosphorylation of JAK2, TYK2, STAT3, and STAT4 proteins in T cells. These results demonstrate that COX-2 inhibitors ameliorate EAE in association with the modulation of IL-12 signaling through JAK-STAT pathway leading to Th1 differentiation and suggest their use in the treatment of MS and other Th1 cell-mediated autoimmune diseases.     

IL-6-deficient mice resist myelin oligodendrocyte glycoprotein-induced autoimmune encephalomyelitis

Experimental autoimmune encephalomyelitis (EAE) is induced by immunization with myelin components including myelin oligodendrocyte glycoprotein (MOG). Myelin-specific Th1 cells enter the central nervous system (CNS) via binding of very late antigen 4 (VLA-4) to the endothelial vascular cell adhesion molecule 1 (VCAM-1). In the present study, mice with a homologous disruption of the gene encoding IL-6 are found to be resistant to MOG-induced EAE as evidenced by absence of clinical symptoms, minimal infiltration of CD3⁺ T cells and monocytes into the CNS and lack of demyelination. The failure to induce EAE in IL-6^{− / −} mice is not due to the absence of priming, since lymphocytes of immunized IL-6^{− / −} mice proliferate in response to MOG and produce pro-inflammatory cytokines including IL-2 and IFN-γ. However, in MOG-immunized IL-6^{− / −} mice, serum anti-MOG antibody titers were found to be drastically reduced. This observation is unlikely to be responsible for resistance to EAE, because B cell-deficient (μMT) mice proved to be fully susceptible to the disease. A striking difference between MOG-immunized wild-type (wt) and IL-6^{− / −} mice was the expression of endothelial VCAM-1 and ICAM-1, which were dramatically up-regulated in the CNS in wt but not in IL-6^{− / −} mice. Taking into account recent studies on the role of VCAM-1 in the entry of Th1 cells into the CNS, the absence of VCAM-1 on endothelial cells in IL-6^{− / −} mice may explain their resistance to EAE.     

Infection of non-encapsulated species of Trichinella ameliorates experimental autoimmune encephalomyelitis involving suppression of Th17 and Th1 response

Epidemiological and experimental studies have indicated that helminth infections can ameliorate autoimmune diseases. The present study investigated the amelioration effect of the Trichinella pseudospiralis infection on experimental autoimmune encephalomyelitis (EAE), a T-cell-mediated autoimmune disease of central nervous system (CNS), and expression kinetics of Th17 and Th1 cytokine which play a crucial role in the pathogenesis of EAE. The results indicated that the infection of helminth T. pseudospiralis obviously ameliorated clinical severity and greatly delayed the onset of EAE induced by myelin oligodendrocyte glycoprotein (MOG) immunization. Infection caused much lesser inflammatory infiltration and demyilination in the CNS of infected EAE mice than uninfected EAE mice. The reduced infiltration was also suggested by the expressions of the inflammation cytokines, IL-17, IL-6, IL-1β, IFN-γ, and TNF-α, which were high in the spinal cords of the uninfected EAE mice, but was nearly normal or low in the infected EAE mice. The increased production of MOG-induced IL-17 and IFN-γ and the expression of IL-6, IL-1β, TGF-β in splenocytes after restimulation with MOG was inhibited in the infected EAE mice. On the other hand, the greatly induced Th2 response was observed in the splenocytes of the infected EAE mice. The present study showed that T. pseudospiralis infection can suppresses EAE by reducing the inflammatory infiltration in CNS, likely associated with the suppression of Th17 and Th1 responses by the infection.     

Successive tick infestations selectively promote a T-helper 2 cytokine profile in mice

Several studies have revealed that T lymphocytes and cytokines play a crucial role in determining the outcome of parasitic infections in terms of protective immunity. In this study we found that Rhipicephalus sanguineus tick saliva stimulates transforming growth factor-beta (TGF-beta), and reduces interleukin-12 (IL-12) secretion by cells from normal C3H/HeJ mice. Moreover, murine lymph node cells harvested 6 days after the fourth infestation with ticks presented an 82.4% decrease in their proliferative response to concanavalin A (Con A) compared with the response of control cells. In addition, lymph node cells cultured in the presence of Con A showed a T-helper 2-type (Th2-type) cytokine profile, represented by augmented IL-4 and IL-10 and TGF-beta. On the other hand, the IL-2, interferon-gamma (IFN-gamma) and IL-12 synthesis was significantly inhibited. These results indicate that ticks may modulate the host's immune response through saliva injection. Considering that C3H/HeJ mice develop no protective immunity to R. sanguineus infestation, our results suggest that tick-induced Th2-type cytokines and a decreased proliferative response probably lead the host to a susceptible state to both tick and tick-transmitted pathogens.     

Differential cytokine and chemokine production characterizes experimental autoimmune meningitis and experimental autoimmune encephalomyelitis

After primary immunization with myelin/oligodendrocyte glycoprotein, CD28(-/-) mice developed experimental autoimmune meningitis (EAM) rather than experimental autoimmune encephalomyelitis (EAE). Cytokine and chemokine production in EAE and EAM were compared to understand the differences in disease phenotype. T cells from the central nervous system lesions of mice with either EAE or EAM expressed intracellular TNF-alpha. Splenic T cells from mice with EAM produced TNF-alpha and IL-6 but no IL-2. Conversely, EAE-derived splenic T cells produced TNF-alpha and IL-2 but no IL-6. Altered T cell differentiation in EAM was not due to a Th1 to Th2 shift, because equivalent amounts of T cell IFN-gamma mRNA were produced in both diseases. Neutrophils also produced inflammatory mediators such as TNF-alpha and IL-6 in EAM. Autocrine production of MIP-2 mRNA was observed in neutrophils from mice with EAM but not EAE. Therefore, distinct patterns of cytokines and chemokines distinguish EAE and EAM.     

Autoimmune inflammation from the Th17 perspective

Recent studies demonstrated an IL-17-producer CD4+ T cell subpopulation, termed Th17, distinct from Th1 and Th2. It represents a different pro-inflammatory Th-cell lineage. This notion is supported by gene-targeted mice studies. Mice lacking IL-23 (p19-/-) do not develop experimental autoimmune encephalomyelitis (EAE) or collagen-induced arthritis (CIA), while knockout mice for the Th1 cytokine IL-12 (p35-/-) strongly develop both autoimmune diseases. Disease resistance by IL-23 knockout mice correlates well with the absence of IL-17-producing CD4(+) T lymphocytes in target organs despite normal presence of antigen-specific-IFN-gamma-producing Th1 cells. This finding may thus explain previous contradictory reports showing that anti-IFN-gamma-treated mice, IFN-gamma- or IFNR-deficient mice develop CIA or EAE. TGF-beta, IL-6 and IL-1 are the differentiation factors of Th17 cells. IL-23 is dispensable for this function, but necessary for Th17 expansion and survival. The master regulator that directs the differentiation program of Th17 cells is the orphan nuclear receptor RORgammat. IL-27, a member of the IL-12/IL-23 family, potently inhibits Th17 development. Evidence suggesting rheumatoid arthritis and multiple sclerosis as primarily IL-17 autoimmune inflammatory-mediated diseases is rapidly accumulating. The IL-17/23 axis of inflammation and related molecules may rise as therapeutic targets for treating these and perhaps other autoimmune diseases.     

The central nervous system environment controls effector CD4+ T cell cytokine profile in experimental allergic encephalomyelitis

In experimental allergic encephalomyelitis (EAE), CD4⁺ T cells infiltrate the central nervous system (CNS). We derived CD4⁺ T cell lines from SJL/J mice that were specific for encephalitogenic myelin basic protein (MBP) peptides and produced both Th1 and Th2 cytokines. These lines transferred EAE to naive mice. Peptide-specific cells re-isolated from the CNS only produced Th1 cytokines, whereas T cells in the lymph nodes produced both Th1 and Th2 cytokines. Mononuclear cells isolated from the CNS, the majority of which were microglia, presented antigen to and stimulated MBP-specific T cell lines in vitro. Although CNS antigen-presenting cells (APC) supported increased production of interferon (IFN)-γ mRNA by these T cells, there was no increase in the interleukin (IL)-4 signal, whereas splenic APC induced increases in both IFN-γ and IL-4. mRNA for IL-12 (p40 subunit) was up-regulated in both infiltrating macrophages and resident microglia from mice with EAE. We have thus shown that a Th1 cytokine bias within the CNS can be induced by CNS APC, and that IL-12 is up-regulated in microglial cells within the CNS of mice with EAE. Microglia may therefore control Th1 cytokine responses within the CNS.     

Experimental autoimmune encephalomyelitis in IL-4-deficient mice

Experimental autoimmune encephalomyelitis (EAE) in an inflammatory demyelinating disease which usually follows a monophasic course. Autoreactive Th1 CD4+ T cells are responsible for the lesions, whereas autoreactive Th2 CD4+ T cells can, upon adoptive transfer, suppress the disease process. However, the role of IL-4 and Th2 cells in the spontaneous remission of EAE and in the prevention of relapses is not known. We have addressed these issues using IL-4-deficient mice in which the differentiation of Th2 CD4+ T cells is severely compromised. The clinical course of actively induced EAE was compared in IL-4+/+, IL- 4+ /- and IL-4-/- mice on the PL/J genetic background. No significant differences were noted between groups for the frequency, severity and duration of EAE, and the frequency of relapses. Our results indicate that IL-4, despite its well-documented regulatory role in EAE, is not necessary for the spontaneous remission of disease or for the prevention of relapses. Therefore, in the absence of IL-4, overlapping or compensatory immunoregulatory mechanisms can restrict an inflammatory response within the central nervous system.      

Infection with Toxoplasma gondii reduces established and developing Th2 responses induced by Nippostrongylus brasiliensis infection

Oral infection of C57BL/6 mice with 100 cysts of the protozoan parasite Toxoplasma gondii results in the development of small intestinal Th1-type immunopathology. In contrast, infection with intestinal helminths results in the development of protective Th2-type responses. We investigated whether infection with the helminth Nippostrongylus brasiliensis influences the development of T. gondii-induced Th1 responses and immunopathology in C57BL/6 mice infected with T. gondii. Prior as well as simultaneous infection of mice with N. brasiliensis did not alter the course of infection with 100 cysts of T. gondii. Coinfected mice produced high levels of interleukin-12 (IL-12) and gamma interferon (IFN-gamma), developed small intestinal immunopathology, and died at the same time as mice infected with T. gondii. Interestingly, local and systemic N. brasiliensis-induced Th2 responses, including IL-4 and IL-5 production by mesenteric lymph node and spleen cells and numbers of intestinal goblet cells and blood eosinophils, were markedly lower in coinfected than in N. brasiliensis-infected mice. Similar effects were seen when infection with 10 T. gondii cysts was administered following infection with N. brasiliensis. Infection of C57BL/6 mice with 10 T. gondii cysts prior to coinfection with N. brasiliensis inhibited the development of helminth-induced Th2 responses and was associated with higher and prolonged N. brasiliensis egg production. In contrast, oral administration of Toxoplasma lysate prior to N. brasiliensis infection had only a minor and short-lived effect on Th2 responses. Thus, N. brasiliensis-induced Th2 responses fail to alter T. gondii-induced Th1 responses and immunopathology, most likely because Th1 responses develop unchanged in C57BL/6 mice with a prior or simultaneous infection with N. brasiliensis. Our findings contribute to the understanding of immune regulation in coinfected animals and may assist in the design of immunotherapies for human Th1 and Th2 disorders.     

In the absence of IL-12, the induction of Th1-mediated protective immunity by the attenuated schistosome vaccine is impaired,revealing an alternative pathway with Th2-type characteristics

Vaccination of mice with irradiated Schistosoma mansoni larvae confers high levels of immunity which is mediated by Th1-type lymphocytes. To investigate a possible role for IL-12 in the induction of protection, we have compared the immune response of IL-12 p40-deficient (KO) mice and their C57BL/6 (WT) counterparts following vaccination. Cultured lymph node cells from KO mice had markedly altered cytokine profiles with significantly decreased production of IFN-γ increased IL-4. Correspondingly, KO mice had enhanced levels of IgE. After challenge, cells recovered from the lungs of KO mice secreted abundant IL-4 and IL-5 but little IFN-γ, while flow cytometric and histological analysis of lung cell populations recorded a very high proportion of eosinophils. The levels of protection in KO mice were substantially lower than in their WT counterparts, demonstrating the importance of IL-12 and Th1-mediated immune responses. This conclusion is reinforced by the administration of rIL-12 to KO mice immediately after vaccination which led to increased IFN-γ and the restoration of protective immunity. Nevertheless, the data also indicated that the limited levels of protection induced in KO mice occur via an IL-12-independent pathway, possibly mediated by Th2 cells.     

细胞膜异位表达钙网蛋白的CD4~+T细胞诱导EAE小鼠保护性免疫

目的:研究细胞膜表面异位表达钙网蛋白(calreticulin,CALR)对T细胞疫苗(T-cell vaccine,TCV)诱导的保护性免疫效果的影响。方法:采用小鼠髓鞘少突胶质细胞糖蛋白35-55(MOG_(35-55))免疫C57BL/6小鼠建立实验性自身免疫性脑脊髓炎(EAE)模型,分别以MOG_(35-55)特异性T细胞(CALR~+T及CALR~-T)为疫苗,通过尾静脉注射免疫小鼠。检测指标包括EAE小鼠临床评分比较、脾CD4~+ CD25~+ Foxp3~+调节性T细胞百分比测定及血清中细胞因子干扰素γ(IFN-γ)、白细胞介素4(IL-4)、IL-10和IL-17A含量测定。结果:射线照射可诱导活化CD4~+T细胞表面异位表达CALR;CALR~+T免疫组症状显著轻于CALR~-T免疫组(P0.01);CALR~+T免疫组小鼠脾CD4~+ CD25~+ Foxp3~+调节性T细胞百分比及血清中IL-4和IL-10含量显著高于对照组(P0.01),而IFN-γ和IL-17A含量显著低于对照组(P0.01),结论:细胞膜表面异位表达CALR与TCV诱导的保护性免疫效果有关。     

Ebastine inhibits T cell migration, production of Th2-type cytokines and proinflammatory cytokines

BACKGROUND: Cytokine imbalance and cellular migration to inflammatory sites are critical components of allergic diseases. Redirecting cytokine imbalance and inhibiting cell migration therefore represent important therapeutic strategies for the treatment of these disorders. OBJECTIVES: To study the in vitro effect of ebastine, a novel non-sedating H1 receptor antagonist, on cytokine secretion and migration of activated T cells, as well as production of pro-inflammatory cytokines by macrophages. METHODS: Peripheral T cells obtained from healthy volunteers were cultured in wells coated with the combination of anti-CD3 monoclonal antibody (mAb) and anti-CD26 mAb, anti-CD3 mAb and anti-CD28 mAb, or anti-CD3 mAb with PMA, in the presence or absence of ebastine. T cell proliferation and the production of cytokines were measured by [3H]thymidine incorporation assay and ELISA, respectively. In addition, transendothelial migration of T cells and production of pro-inflammatory cytokines by macrophages were examined. RESULTS: Ebastine inhibited T cell proliferation and the production of IL-4, IL-5, IL-6, and TNF-alpha by T cells under each co-stimulatory condition tested, whereas it exhibited no effect on the production of IL-2 or IFN-gamma. In addition, T cell migration and the production of such pro-inflammatory cytokines as TNF-alpha and IL-6 by macrophages were inhibited by ebastine. CONCLUSIONS: These results indicate that ebastine has a specific inhibitory effect on Th2-type cytokine production. Moreover, ebastine inhibited T cell migration and pro-inflammatory cytokine production by T cells and macrophages, suggesting that ebastine might be useful for the treatment of T cell-mediated allergic inflammatory disorders, including asthma, atopic dermatitis, and Th2-type autoimmune diseases.     

A Distinct Role of CD4<Superscript>+</Superscript> Th17- and Th17-Stimulated CD8<Superscript>+</Superscript> CTL in the Pathogenesis of Type 1 Diabetes and Experimental Autoimmune Encephalomyelitis

Both CD4(+) Th17-cells and CD8(+) cytotoxic T lymphocytes (CTLs) are involved in type 1 diabetes and experimental autoimmune encephalomyelitis (EAE). However, their relationship in pathogenesis of these autoimmune diseases is still elusive. We generated ovalbumin (OVA)- or myelin oligodendrocyte glycoprotein (MOG)-specific Th17 cells expressing RORγt and IL-17 by in vitro co-culturing OVA-pulsed and MOG(35-55) peptide-pulsed dendritic cells (DC(OVA) and DC(MOG)) with CD4(+) T cells derived from transgenic OTII and MOG-T cell receptor mice, respectively. We found that these Th17 cells when transferred into C57BL/6 mice stimulated OVA- and MOG-specific CTL responses, respectively. To assess the above question, we adoptively transferred OVA-specific Th17 cells into transgenic rat insulin promoter (RIP)-mOVA mice or RIP-mOVA mice treated with anti-CD8 antibody to deplete Th17-stimulated CD8(+) T cells. We demonstrated that OVA-specific Th17-stimulated CTLs, but not Th17 cells themselves, induced diabetes in RIP-mOVA. We also transferred MOG-specific Th17 cells into C57BL/6 mice and H-2K(b-/-) mice lacking of the ability to generate Th17-stimulated CTLs. We further found that MOG-specific Th17 cells, but not Th17-activated CTLs induced EAE in C57BL/6 mice. Taken together, our data indicate a distinct role of Th17 cells and Th17-stimulated CTLs in the pathogenesis of TID and EAE, which may have great impact on the overall understanding of Th17 cells in the pathogenesis of autoimmune diseases.