Astrocyte-targeted expression of IL-12 induces active cellular immune responses in the central nervous system and modulates experimental allergic encephalomyelitis

The role of IL-12 in the evolution of immunoinflammatory responses at a localized tissue level was investigated. Transgenic mice were developed with expression of either both the IL-12 subunits (p35 and p40) or only the IL-12 p40 subunit genes targeted to astrocytes in the mouse CNS. Glial fibrillary acidic protein (GF)-IL-12 mice, bigenic for the p35 and p40 genes, developed neurologic disease which correlated with the levels and sites of transgene-encoded IL-12 expression. In these mice, the brain contained numerous perivascular and parenchymal inflammatory lesions consisting of predominantly CD4+ and CD8+ T cells as well as NK cells. The majority of the infiltrating T cells had an activated phenotype (CD44high, CD45Rblow, CD62Llow, CD69high, VLA-4 high, and CD25+). Functional activation of the cellular immune response was also evident with marked cerebral expression of the IFN-gamma, TNF, and IL-1alphabeta genes. Concomitant with leukocyte infiltration, the CNS expression of immune accessory molecules was induced or up-regulated, including ICAM-1, VCAM-1, and MHC class II and B7-2. Glial fibrillary acidic protein-p40 mice with expression of IL-12 p40 alone remained asymptomatic, with no inflammation evident at any age studied. The effect of local CNS production of IL-12 in the development of experimental autoimmune encephalomyelitis was studied. After immunization with myelin oligodendrocyte glycoprotein-peptides, GF-IL-12 mice had an earlier onset and higher incidence but not more severe disease. We conclude that localized expression of IL-12 by astrocytes can 1) promote the spontaneous development of activated type 1 T cell and NK cellular immunity and cytokine responses in the CNS, and 2) promote more effective Ag-specific T cell dynamics but not activity in experimental autoimmune encephalomyelitis.     

Cutting edge: Multiple sclerosis-like lesions induced by effector CD8 T cells recognizing a sequestered antigen on oligodendrocytes

CD8 T cells are emerging as important players in multiple sclerosis (MS) pathogenesis, although their direct contribution to tissue damage is still debated. To assess whether autoreactive CD8 T cells can contribute to the pronounced loss of oligodendrocytes observed in MS plaques, we generated mice in which the model Ag influenza hemagglutinin is selectively expressed in oligodendrocytes. Transfer of preactivated hemagglutinin-specific CD8 T cells led to inflammatory lesions in the optic nerve, spinal cord, and brain. These lesions, associating CD8 T cell infiltration with focal loss of oligodendrocytes, demyelination, and microglia activation, were very reminiscent of active MS lesions. Thus, our study demonstrates the potential of CD8 T cells to induce oligodendrocyte lysis in vivo as a likely consequence of direct Ag-recognition. These results provide new insights with regard to CNS tissue damage mediated by CD8 T cells and for understanding the role of CD8 T cells in MS.     

The IL-7Rα pathway is quantitatively and functionally altered in CD8 T cells in multiple sclerosis

The IL-7Rα single nucleotide polymorphism rs6897932 is associated with an increased risk for multiple sclerosis (MS). IL-7Rα is a promising candidate to be involved in autoimmunity, because it regulates T cell homeostasis, proliferation, and antiapoptotic signaling. However, the exact underlying mechanisms in the pathogenesis of MS are poorly understood. We investigated whether CD4 and CD8 lymphocyte subsets differed in IL-7Rα expression and functionality in 78 MS patients compared with 59 healthy controls (HC). A significantly higher frequency of IL-7Rα(+) CD8 effector memory (CD8EM) was found in MS. Moreover, IL-7Rα membrane expression was significantly increased in MS in naive and memory CD8 (all p < 0.05) with a similar trend in CD8EM (p = 0.055). No correlation was found between the expression level or frequency of IL-7Rα(+)CD8(+) and rs6897932 risk allele carriership. Upon IL-7 stimulation, MS patients had stronger STAT5 activation in CD8EM compared with HC. IL-7 stimulation had a differential effect on both mRNA and protein expression of granzyme A and granzyme B between MS and HC. Stainings of different lesions in postmortem MS brain material showed expression of IL-7 and CD8(+)IL-7Rα(+) in preactive, but not in active, demyelinating MS lesions, indicating involvement of IL-7Rα(+) lymphocytes in lesion development. The intralesional production of IL-7 in combination with the lower threshold for IL-7-induced cytotoxicity in MS may enhance the pathogenicity of these CD8 T cells. This is of special interest in light of the established demyelinating and cytotoxic actions of granzyme A.     

Interleukin-13 secretion by normal and posttransplant T lymphocytes; in vitro studies of cellular immune responses in the presence of acute leukaemia blast cells

T lymphocyte secretion of interleukin-13 (IL-13) in response to different activation signals was characterized in vitro. IL-13 release was investigated when virus transformed B lymphocytes or acute myelogenous leukaemia (AML) blasts were used as accessory cells during T cell activation. First, a majority of both CD4⁺ and CD8⁺ TCRαβ⁺ T lymphocyte clones, derived from normal individuals and bone marrow transplant recipients, secreted IL-13 in response to a standardized mitogenic activation signal (phytohaemagglutinin+IL-2+ B lymphocyte accessory cells). The CD4⁺ cells showed significantly higher IL-13 levels than the CD8⁺ subsets. Second, when leukaemic accessory cells (more than 95% AML blasts) were used during T cell activation, IL-13 was released both during alloactivation of normal T lymphocytes and during mitogen activation of posttransplant T cells. Third, when normal T lymphocytes were stimulated with allogeneic AML blasts, addition of IL-13-neutralizing monoclonal antibodies decreased interferon γ levels. Although addition of IL-13-neutralizing antibodies did not alter granulocyte-colony-stimulating factor secretion by allostimulating AML blasts, altered blast proliferation was detected for certain patients. Thus, most T cell clones can release IL-13, and IL-13 can modulate cytokine responses during T cell recognition of allogeneic AML cells. Received: 24 April 1997 / Accepted: 24 July 1997     

The T cell chemoattractant IFN-inducible protein 10 is essential in host defense against viral-induced neurologic disease

The contribution of the T cell chemoattractant chemokine IFN-inducible protein 10 (IP-10) in host defense following viral infection of the CNS was examined. IP-10 is expressed by astrocytes during acute encephalomyelitis in mouse hepatitis virus-infected mice, and the majority of T lymphocytes infiltrating into the CNS expressed the IP-10 receptor CXCR3. Treatment of mice with anti-IP-10 antisera led to increased mortality and delayed viral clearance from the CNS as compared with control mice. Further, administration of anti-IP-10 led to a >70% reduction (p 相似文献   

B cell-derived IL-15 enhances CD8 T cell cytotoxicity and is increased in multiple sclerosis patients

Multiple lines of evidence suggest that CD8 T cells contribute to the pathogenesis of multiple sclerosis (MS). However, the sources and involvement of cytokines such as IL-15 in activating these cells is still unresolved. To investigate the role of IL-15 in enhancing the activation of CD8 T cells in the context of MS, we determined cell types expressing the bioactive surface IL-15 in the peripheral blood of patients and evaluated the impact of this cytokine on CD8 T cell cytotoxicity and migration. Flow cytometric analysis showed a significantly greater proportion of B cells and monocytes from MS patients expressing IL-15 relative to controls. We established that CD40L activation of B cells from healthy donors increased their IL-15 levels, reaching those of MS patients. We also demonstrated an enhanced cytotoxic profile in CD8 T cells from MS patients upon stimulation with IL-15. Furthermore, we showed that IL-15 expressed by B cells and monocytes is sufficient and functional, enhancing granzyme B production by CD8 T cells upon coculture. Exposure of CD8 T cells to this cytokine enhanced their ability to kill glial cells as well as to migrate across an in vitro inflamed human blood-brain barrier. The elevated levels of IL-15 in patients relative to controls, the greater susceptibility of CD8 T cells from patients to IL-15, in addition to the enhanced cytotoxic responses by IL-15-exposed CD8 T cells, stresses the potential of therapeutic strategies to reduce peripheral sources of IL-15 in MS.     

Cutting edge: CD8 T cell-mediated demyelination is IFN-gamma dependent in mice infected with a neurotropic coronavirus

Mice infected with the murine coronavirus, mouse hepatitis virus, strain JHM (MHV) develop an immune-mediated demyelinating encephalomyelitis. We showed previously that adoptive transfer of MHV-immune splenocytes depleted of either CD4 or CD8 T cells to infected RAG1(-/-) recipients (mice deficient in recombination activation gene 1) resulted in demyelination. Herein we show that transfer of CD8 T cell-enriched splenocytes from MHV-immune IFN-gamma(-/-) donors resulted in a substantial decrease in demyelination (4.8% of the white matter of the spinal cord compared with 26.3% in those receiving cells from C57BL/6 donors). Similar numbers of lymphocytes were present in the CNS of recipients of either C57BL/6 or IFN-gamma(-/-) CD8 T cells, suggesting that IFN-gamma was not crucial for lymphocyte entry into the CNS. Rather, IFN-gamma was critical for optimal activation or migration of macrophages or microglia into the white matter in the context of CD8 T cell-mediated demyelination.     

Cellular immune responses in acute leukaemia patients with severe chemotherapy-induced leucopenia; characterization of the cytokine repertoire of clonogenic T cells

 T lymphocytes are important both for the host defence against infections and probably also as antileukaemic effector cells in patients with acute leukaemia. To investigate the T lymphocyte cytokine repertoire of clonogenic T lymphocytes, CD4⁺ and CD8⁺ T lymphocyte clones were prepared from acute leukaemia patients with chemotherapy-induced cytopenia (leucocytes <0.5×10⁹/l). A majority of both CD4⁺ and CD8⁺ clones secreted detectable interleukin-2 (IL-2), IL-10, IL-13, granulocyte/macrophage-colony-stimulating factor and interferon γ (IFNγ) in response to phytohaemagglutinin + accessory cells (Epstein-Barr-virus-transformed B cell line, 80-Gy-irradiated). The CD4⁺ clones showed significantly higher levels of IL-10 secretion than the CD8⁺ clones. Decreased levels of IL-2, IL-13 and IFNγ were observed when acute myelogenous leukaemia (AML) blasts were used instead of cells from the B cell line as accessory cells during phytohaemagglutinin activation, but the differences in IL-13 and IFNγ levels were reversed by addition of exogenous IL-2. On the basis of these results we conclude: (i) the remaining clonogenic T lymphocytes derived from acute leukaemia patients with therapy-induced leucopenia can respond to activation with a broad cytokine response, and T-cell-derived cytokines may then contribute to cytokine responses during complicating infections in these patients; (ii) although T cells can modulate AML blast functions and mediate antileukaemic effects, the leukaemia blasts will also modulate T cell functions and alter the cytokine profile of activated T lymphocytes. Received: 6 November 1997 / Accepted: 5 March 1998     

Cutaneous lymphocyte antigen expression on activated lymphocytes and its association with IL-12R (beta1 and beta2), IL-2Ralpha, and CXCR3

The majority of T lymphocytes that infiltrate psoriatic lesions express cutaneous lymphocyte antigen (CLA), a skin homing receptor involved in the influx of memory T cells to cutaneous sites. We investigated CLA expression on normal human peripheral blood mononuclear cells (PBMCs) and evaluated its association with IL-12 receptors, chemokine receptor, CXCR3, and IL-2Ralpha. PBMCs were stimulated in vitro with or without polyclonal activators (mitogen, or superantigens, or anti-CD3+anti-CD28) in the presence or absence of exogenous rhIL-12. The percentage of CLA+ T lymphocytes increased significantly after superantigen stimulation compared to anti-CD3+anti-CD28 or mitogen activation. The majority of activation induced CLA+ T lymphocytes co-expressed IL-12Rbeta1, IL-12Rbeta2, CXCR3, and CD25 in the presence of rhIL-12. Our results indicate that CLA expression on activated T lymphocytes is IL-12 and activation dependent and correlates with the expression of IL-12 receptors, IL-2Ralpha, and CXCR3. Monitoring the levels of Th1 differentiation markers such as CXCR3 and IL-12Rbeta2 along with activation marker, CD25 on skin homing CLA+ T lymphocytes may provide insight into the mechanism of action of immunotherapies directed against Th1 type skin inflammatory diseases.     

Functional maturation of adult mouse resting microglia into an APC is promoted by granulocyte-macrophage colony-stimulating factor and interaction with Th1 cells

A precise knowledge of the early events inducing maturation of resting microglia into a competent APC may help to understand the involvement of this cell type in the development of CNS immunopathology. To elucidate whether signals from preactivated T cells are sufficient to induce APC features in resting microglia, microglia from the adult BALB/c mouse CNS were cocultured with Th1 and Th2 lines from DO11.10 TCR transgenic mice to examine modulation of APC-related molecules and Ag-presenting capacity. Upon Ag-specific interaction with Th1, but not Th2, cells, microglia strongly up-regulated the surface expression of MHC class II, CD40, and CD54 molecules. Induction of CD86 on mouse microglia did not require T cell-derived signals. Acutely isolated adult microglia stimulated Th1 cells to secrete IFN-gamma and, to a lesser extent, IL-2, but were inefficient stimulators of IL-4 secretion by Th2 cells. Microglia exposed in vitro to IFN-gamma showed enhanced expression of MHC class II, CD40, and CD54 molecules and became able to restimulate Th2 cells. In addition to IFN-gamma, GM-CSF increased the ability of microglia to activate Th1, but not Th2, cells without up-regulating MHC class II, CD40, or CD54 molecules. These results suggest that interaction with Th1 cells and/or Th1-secreted soluble factors induces the functional maturation of adult mouse microglia into an APC able to sustain CD4+ T cell activation. Moreover, GM-CSF, a cytokine secreted by T cells as well as reactive astrocytes, could prime microglia for Th1-stimulating capacity, possibly by enhancing their responsiveness to Th1-derived signals.     

Mechanisms of IL-10 production in human microglia-T cell interaction.

IL-10, a cytokine with important anti-inflammatory properties, is generated within the CNS during neuroinflammation. The mechanism for its production is poorly understood. Since infiltrating lymphocytes come into close proximity with the macrophage-like cells of the CNS, the microglia, we have used an in vitro human microglia-T cell coculture system to address the mechanisms of IL-10 production. We demonstrate that microglia or activated T cells alone secrete negligible amounts of IL-10, but that their coculture results in significant IL-10 production, which was effected by both cell types. IL-10 generation was cell contact dependent, and treatment with anti-CD40, CTLA-4-Fc, or anti-CD23 decreased the IL-10 content in microglia-T cell cocultures. The combination of anti-CD40 and CTLA-4-Fc reduced IL-10 levels to the negligible amounts seen with T cells or microglia in isolation. By also measuring TNF-alpha levels, specificity of cytokine regulation was observed; while anti-CD40 and CTLA-4-Fc reduced IL-10 and TNF-alpha levels, anti-CD23 did not affect TNF-alpha while attenuating IL-10 generation. Anti-very late Ag-4, which decreased TNF-alpha levels, did not affect IL-10. These results implicate the CD40, B7, and CD23 pathways in IL-10 production following microglia-T cell encounter and have relevance to the regulation of an anti-inflammatory response within the CNS.     

Selective expansion and partial activation of human NK cells and NK receptor-positive T cells by IL-2 and IL-15.

IL-2 and IL-15 are lymphocyte growth factors produced by different cell types with overlapping functions in immune responses. Both cytokines costimulate lymphocyte proliferation and activation, while IL-15 additionally promotes the development and survival of NK cells, NKT cells, and intraepithelial lymphocytes. We have investigated the effects of IL-2 and IL-15 on proliferation, cytotoxicity, and cytokine secretion by human PBMC subpopulations in vitro. Both cytokines selectively induced the proliferation of NK cells and CD56(+) T cells, but not CD56(-) lymphocytes. All NK and CD56(+) T cell subpopulations tested (CD4(+), CD8(+), CD4(-)CD8(-), alphabetaTCR(+), gammadeltaTCR(+), CD16(+), CD161(+), CD158a(+), CD158b(+), KIR3DL1(+), and CD94(+)) expanded in response to both cytokines, whereas all CD56(-) cell subpopulations did not. Therefore, previously reported IL-15-induced gammadelta and CD8(+) T cell expansions reflect proliferations of NK and CD56(+) T cells that most frequently express these phenotypes. IL-15 also expanded CD8alpha(+)beta(-) and Valpha24Vbeta11 TCR(+) T cells. Both cytokines stimulated cytotoxicity by NK and CD56(+) T cells against K562 targets, but not the production of IFN-gamma, TNF-alpha, IL-2, or IL-4. However, they augmented cytokine production in response to phorbol ester stimulation or CD3 cross-linking by inducing the proliferation of NK cells and CD56(+) T cells that produce these cytokines at greater frequencies than other T cells. These results indicate that IL-2 and IL-15 act at different stages of the immune response by expanding and partially activating NK receptor-positive lymphocytes, but, on their own, do not influence the Th1/Th2 balance of adaptive immune responses.     

Contribution of CD8 T lymphocytes to the immuno-pathogenesis of multiple sclerosis and its animal models

Multiple sclerosis (MS) is an inflammatory disease of the central nervous system (CNS) characterized by multi-focal demyelination, axonal loss, and immune cell infiltration. Numerous immune mediators are detected within MS lesions, including CD4⁺ and CD8⁺ T lymphocytes suggesting that they participate in the related pathogenesis. Although CD4⁺ T lymphocytes are traditionally considered the main actors in MS immunopathology, multiple lines of evidence suggest that CD8⁺ T lymphocytes are also implicated in the pathogenesis. In this review, we outline the recent literature pertaining to the potential roles of CD8⁺ T lymphocytes both in MS and its animal models. The CD8⁺ T lymphocytes detected in MS lesions demonstrate characteristics of activated and clonally expanded cells supporting the notion that these cells actively contribute to the observed injury. Moreover, several experimental in vivo models mediated by CD8⁺ T lymphocytes recapitulate important features of the human disease. Whether the CD8⁺ T cells can induce or aggravate tissue destruction in the CNS needs to be fully explored. Strengthening our understanding of the pathogenic potential of CD8⁺ T cells in MS should provide promising new avenues for the treatment of this disabling inflammatory disease.     

Peroxisome proliferator-activated receptor-gamma agonists suppress the production of IL-12 family cytokines by activated glia

The IL-12 family of cytokines, which include IL-12, IL-23, and IL-27, play critical roles in the differentiation of Th1 cells and are believed to contribute to the development of multiple sclerosis (MS) and experimental autoimmune encephalomyelitis (EAE), an animal model of MS. Relatively little is known concerning the expression of IL-12 family cytokines by cells of the CNS, the affected tissue in MS. Previously, we and others demonstrated that peroxisome proliferator-activated receptor (PPAR)-gamma agonists suppress the development of EAE, alter T cell proliferation and phenotype, and suppress the activation of APCs. The present studies demonstrated that PPAR-gamma agonists, including the naturally occurring 15-deoxy-Delta(12,14)-PGJ(2) and the synthetic thiazoladinedione rosiglitazone, inhibited the induction of IL-12p40, IL-12p70 (p35/p40), IL-23 (p19/p40), and IL-27p28 proteins by LPS-stimulated primary microglia. In primary astrocytes, LPS induced the production of IL-12p40, IL-23, and IL-27p28 proteins. However, IL-12p70 production was not detected in these cells. The 15-deoxy-Delta(12,14)-PGJ(2) potently suppressed IL-12p40, IL-23, and IL-27p28 production by primary astrocytes, whereas rosiglitazone suppressed IL-23 and IL-27p28, but not IL-12p40 in these cells. These novel observations suggest that PPAR-gamma agonists modulate the development of EAE, at least in part, by inhibiting the production of IL-12 family cytokines by CNS glia. In addition, we demonstrate that PPAR-gamma agonists inhibit TLR2, MyD88, and CD14 expression in glia, suggesting a possible mechanism by which these agonists modulate IL-12 family cytokine expression. Collectively, these studies suggest that PPAR-gamma agonists may be beneficial in the treatment of MS.     

Local expansion of allergen-specific CD30+Th2-type gamma delta T cells in bronchial asthma.

BACKGROUND: T lymphocytes infiltrating airways during the allergic immune response play a fundamental role in recruiting other specialized cells, such as eosinophils, by secreting interleukin 5 (IL-5), and promoting local and systemic IgE synthesis by producing IL-4. Whether these presumed allergen-specific T cells are of mucosal or systemic origin is still a matter of conjecture. MATERIALS AND METHODS: Immunophenotype, IL-4 production, and in vitro proliferative response to specific or unrelated allergens were analyzed in the bronchoalveolar lavage (BAL) fluid lymphocyte suspensions obtained from untreated patients with allergic asthma. Healthy subjects and patients affected by pulmonary sarcoidosis, a granulomatous lung disease characterized by infiltrating Th1 CD4+ lymphocytes, served as controls. RESULTS: The proportions of gamma delta T lymphocytes, mostly CD4+ or CD4- (-)CD8-, was higher in asthmatic subjects than in controls (p < 0.05). Most BAL gamma delta CD4+ lymphocytes of asthmatic patients displayed the T cell receptor (TCR)-gamma delta V delta 1 chain. While CD30 antigen coexpression on the surface of BAL alpha beta(+) T lymphocytes was low (ranging from 5 to 12%), about half of pulmonary gamma delta T cells coexpressed it. These cells produced IL-4 and negligible amounts of interferon-gamma (IFN gamma), and proliferated in vitro in response to purified specific but not unrelated allergens. In contrast, control or sarcoidosis gamma delta T cells never displayed the CD30 surface molecule or produced significant quantities of IL-4. CONCLUSIONS: These findings not only confirm our previous hypothesis that the allergen-specific Th2-type lymphocytes found in the lungs of asthmatic patients are gamma delta T cells belonging to airway mucosal immunocytes, but also strongly support the notion that asthma is a local rather than a systemic disease.     

Contrasting roles for CD4 vs. CD8 T-cells in a murine model of virally induced "T1 black hole" formation

MRI is sensitive to tissue pathology in multiple sclerosis (MS); however, most lesional MRI findings have limited correlation with disability. Chronic T1 hypointense lesions or "T1 black holes" (T1BH), observed in a subset of MS patients and thought to represent axonal damage, show moderate to strong correlation with disability. The pathogenesis of T1BH remains unclear. We previously reported the first and as of yet only model of T1BH formation in the Theiler's murine encephalitis virus induced model of acute CNS neuroinflammation induced injury, where CD8 T-cells are critical mediators of axonal damage and related T1BH formation. The purpose of this study was to further analyze the role of CD8 and CD4 T-cells through adoptive transfer experiments and to determine if the relevant CD8 T-cells are classic epitope specific lymphocytes or different subsets. C57BL/6 mice were used as donors and RAG-1 deficient mice as hosts in our adoptive transfer experiments. In vivo 3-dimensional MRI images were acquired using a 7 Tesla small animal MRI system. For image analysis, we used semi-automated methods in Analyze 9.1; transfer efficiency was monitored using FACS of brain infiltrating lymphocytes. Using a peptide depletion method, we demonstrated that the majority of CD8 T-cells are classic epitope specific cytotoxic cells. CD8 T-cell transfer successfully restored the immune system's capability to mediate T1BH formation in animals that lack adaptive immune system, whereas CD4 T-cell transfer results in an attenuated phenotype with significantly less T1BH formation. These findings demonstrate contrasting roles for these cell types, with additional evidence for a direct pathogenic role of CD8 T-cells in our model of T1 black hole formation.     

Shifting hierarchies of interleukin-10-producing T cell populations in the central nervous system during acute and persistent viral encephalomyelitis

Interleukin-10 (IL-10) mRNA is rapidly upregulated in the central nervous system (CNS) following infection with neurotropic coronavirus and remains elevated during persistent infection. Infection of transgenic IL-10/green fluorescent protein (GFP) reporter mice revealed that CNS-infiltrating T cells were the major source of IL-10, with minimal IL-10 production by macrophages and resident microglia. The proportions of IL-10-producing cells were initially similar in CD8(+) and CD4(+) T cells but diminished rapidly in CD8(+) T cells as the virus was controlled. Overall, the majority of IL-10-producing CD8(+) T cells were specific for the immunodominant major histocompatibility complex (MHC) class I epitope. Unlike CD8(+) T cells, a large proportion of CD4(+) T cells within the CNS retained IL-10 production throughout persistence. Furthermore, elevated frequencies of IL-10-producing CD4(+) T cells in the spinal cord supported preferential maintenance of IL-10 production at the site of viral persistence and tissue damage. IL-10 was produced primarily by the CD25(+) CD4(+) T cell subset during acute infection but prevailed in CD25(-) CD4(+) T cells during the transition to persistent infection and thereafter. Overall, these data demonstrate significant fluidity in the T-cell-mediated IL-10 response during viral encephalitis and persistence. While IL-10 production by CD8(+) T cells was limited primarily to the time of acute effector function, CD4(+) T cells continued to produce IL-10 throughout infection. Moreover, a shift from predominant IL-10 production by CD25(+) CD4(+) T cells to CD25(-) CD4(+) T cells suggests that a transition to nonclassical regulatory T cells precedes and is retained during CNS viral persistence.     

Differential Pro-Inflammatory Responses of Astrocytes and Microglia Involve STAT3 Activation in Response to 1800 MHz Radiofrequency Fields

Microglia and astrocytes play important role in maintaining the homeostasis of central nervous system (CNS). Several CNS impacts have been postulated to be associated with radiofrequency (RF) electromagnetic fields exposure. Given the important role of inflammation in neural physiopathologic processes, we investigated the pro-inflammatory responses of microglia and astrocytes and the involved mechanism in response to RF fields. Microglial N9 and astroglial C8-D1A cells were exposed to 1800 MHz RF for different time with or without pretreatment with STAT3 inhibitor. Microglia and astrocytes were activated by RF exposure indicated by up-regulated CD11b and glial fibrillary acidic protein (GFAP). However, RF exposure induced differential pro-inflammatory responses in astrocytes and microglia, characterized by different expression and release profiles of IL-1β, TNF-α, IL-6, PGE2, nitric oxide (NO), inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX2). Moreover, the RF exposure activated STAT3 in microglia but not in astrocytes. Furthermore, the STAT3 inhibitor Stattic ameliorated the RF-induced release of pro-inflammatory cytokines in microglia but not in astrocytes. Our results demonstrated that RF exposure differentially induced pro-inflammatory responses in microglia and astrocytes, which involved differential activation of STAT3 in microglia and astrocytes. Our data provide novel insights into the potential mechanisms of the reported CNS impacts associated with mobile phone use and present STAT3 as a promising target to protect humans against increasing RF exposure.     

肥厚性扁平苔藓皮损中浸润淋巴细胞的研究

目的探讨淋巴细胞浸润在肥厚性扁平苔藓发病机制中的意义。方法采用免疫组织化学SP法对10例肥厚性扁平苔藓患者皮损、20例非肥厚性扁平苔藓患者皮损及10例正常人皮肤中CD3、CD4、CD8、CD20进行检测。结果所有患者皮损均以CD3^＋’T、CD4^＋T、CD8^＋T细胞浸润为主,散在CD20^＋B细胞浸润。肥厚性皮损中浸润T淋巴细胞数少于非肥厚性皮损（P〈0．01）,CD20^＋B细胞占浸润淋巴细胞百分率高于非肥厚性皮损（P〈0．05）。正常人皮肤仅在真皮偶见CD3^＋T细胞。结论肥厚性扁平苔藓皮损T淋巴细胞的减少,B淋巴细胞的增多表达可能与疾病的持续存在及局部过度增殖性改变密切相关。     

IL-17A Promotes Granulocyte Infiltration,Myelin Loss,Microglia Activation,and Behavioral Deficits During Cuprizone-Induced Demyelination

Recent evidence suggests a pivotal role of the proinflammatory cytokine interleukin - 17A (IL-17) in demyelinating autoimmune diseases of the central nervous system (CNS) such as multiple sclerosis (MS). Nevertheless, it remains unclear if this cytokine exerts direct effects on CNS resident cells during MS or modulates the function of infiltrating immune cells towards a more detrimental phenotype. Here, we investigated the effects of locally produced IL-17 during experimental demyelination of the CNS using the cuprizone (CPZ) model in mice with (GF/IL17) or without transgenic production of IL-17 by astrocytes in the CNS. During early demyelination, GF/IL17 mice demonstrated enhanced activity and decreased anxiety-related behavior in the elevated plus maze suggesting a more severe disease course. Furthermore, in GF/IL17 mice, toxic demyelination was accelerated and synthesis of myelin proteins was reduced. Early demyelination was accompanied by an increased ratio of infiltrating granulocytes in GF/ILl17 mice. The presence of IL-17 during CPZ treatment increased the accumulation of activated microglia and sustained microglial proliferation during myelin loss. Taken together, our results argue for a detrimental role of IL-17 during demyelinating diseases.