A study of associated cell-mediated immune mechanisms in experimental autoimmune neuritis rats

The aims of this study are to investigate the optimal antigens used to induce acute or chronic EAN and the associated cell-mediated immune mechanisms. Lewis rats were grouped into EAN rats and control rats. EAN rats were immunized by injection into both hind footpads of inoculums containing 100 microg/200 microg of P2 peptide 57-81 and FCA, or 200 mug of P0 peptide 180-199 and FCA. Control rats were immunized by FCA. Clinical scores were compared at the maximum of disease. On the 14th day after immunization, we examined lymphocyte proliferation, fractions of CD4+ T cells within lymph node mononuclear cells (MNC), frequencies of CD4+CD25+ T cells within CD4+ T cells, supernatant productions of IFN-gamma, IL-4, IL-10 and TGF-beta1 secreted by lymphocytes. Histopathology of sciatic nerves was assessed. Our findings indicated: (1) 100 microg of P2 peptide 57-81 and 200 microg of P0 peptide 180-199 may induce an acute EAN and 200 microg of P2 peptide 57-81 may induce a chronic EAN; (2) Lewis rats were more sensitive to P2 peptide 57-81 than P0 peptide 180-199; (3) clinical disease had nothing to do with a change of relative CD4+ T cells number in lymph node MNC; (4) frequencies of CD4+CD25+ T cells and levels of TGF-beta1 secreted by lymphocytes negatively paralleled clinical EAN, while levels of IFN-gamma secreted by lymphocytes roughly paralleled clinical EAN at the acute phase; (5) sciatic nerve sections from the chronic EAN rats didn't show any inflammatory cells, but showed remaining segmental demyelination and axonal collapse at the chronic phase; (6) self-limitation of acute EAN may owe to the rising levels of IL-4 and IL-10, while a longer duration of chronic EAN may owe to the decreasing levels of IL-4 and IL-10.     

Initiation and development of experimental autoimmune neuritis in Lewis rats is independent of the cytotoxic capacity of NKR-P1A+ cells

Natural killer (NK) cells are implicated in T cell-mediated autoimmune diseases. Experimental autoimmune neuritis (EAN) is a CD4+ T cell-mediated animal model of the Guillain-Barré syndrome in human. The role of NK cells in the initiation and development of EAN remains unclear. In the present study, we demonstrate that anti-NKR-P1A monoclonal antibody (mAb) treatment in vivo did not affect the initiation and development of clinical EAN in Lewis rats induced by immunization with peripheral nerve myelin P0 protein peptide 180-199 and Freund's complete adjuvant, as well as the proportion of NKR-P1A+ cells (including NK cells and NKT cells) in the spleen. Furthermore, inflammatory cell infiltrations and demyelination in the peripheral nervous system (PNS) and in vitro P0 peptide 180-199-specific splenocyte proliferation were not different in anti-NKR-P1A mAb-treated rats compared to the control antibody-treated rats. The cytotoxic activity of NKR-P1A+ cells, determined by NK cell-sensitive K562 cells as target cells, decreased markedly in anti-NKR-P1A mAb-treated rats, suggesting that decrease of the cytotoxic activities of NKR-P1A+ cells is not sufficient to alter clinical EAN, although NKR-P1A+ cells may participate in the pathogenesis of T cell-mediated autoimmune diseases, such as EAN, by the mechanisms that involve the release of cytokines.     

P0 glycoprotein peptides 56-71 and 180-199 dose-dependently induce acute and chronic experimental autoimmune neuritis in Lewis rats associated with epitope spreading

Two synthetic peripheral nerve myelin P0 protein peptides, an immunodominant (amino acids 180-199) and a cryptic (amino acids 56-71) one, induced an acute or chronic course of experimental autoimmune neuritis (EAN) in Lewis rats, when given at low dose (50-100 microg/rat) or high dose (250 microg/rat), respectively. Corresponding to the different clinical course, pathological changes and immune responses were found: (1) Onset of clinical signs of P0 peptide 56-71 (P0 56-71) induced EAN was 1-3 days later than in P0 peptide 180-199 (P0 180-199) induced EAN at all immunizing doses, whereas the peak of the disease occurred at a similar time point post immunization (p.i.), i.e. at days 14-16 p.i. in P0 56-71 induced EAN and at day 16 p.i. in P0 180-199 induced EAN. (2) Intramolecular epitope spreading as assessed by delayed type hypersensitivity response occurred in P0 56-71 induced EAN at both low and high antigen doses and in P0 180-199 induced EAN at high antigen dose (250 microg/rat) only. (3) P0 180-199 stimulated higher levels of interferon-gamma production in P0 180-199 induced EAN than in P0 56-71 induced EAN and vice versa. (4) Histopathologic evaluation revealed a similar grade of mononuclear cell infiltration in the sciatic nerves of both types of EAN, but more severe demyelination was found in P0 180-199 induced EAN compared to P0 56-71 induced EAN. The results support the hypothesis that high dose autoantigen immunization induces extensive determinant spreading and chronic course of autoimmune diseases.     

CD28-B7 costimulation: a critical role for initiation and development of experimental autoimmune neuritis in C57BL/6 mice

CD28 provides a critical costimulatory signal for antigen-specific T cell activation. Because CD28 is an important factor in the development of autoimmune diseases, we investigated its role in T cell-mediated experimental autoimmune neuritis (EAN), an animal model of Guillain-Barré syndrome in humans. CD28-deficient mutant (CD28-/-) C57BL/6 mice and corresponding wild-type mice were immunized with P0 peptide 180-199, a purified component of peripheral nerve myelin, and Freund's complete adjuvant. As a result, all wild-type mice developed severe EAN, in contrast, none of the CD28-/- mice manifested clinical signs of disease. Additionally, CD28-/- mice had fewer IL-12 producing cells in sciatic nerve sections and fewer IFN-gamma secreting splenic cells than wild-type mice on day 24 post immunization, i.e., at the peak of clinical EAN. At that time point, CD28-/- mice had milder infiltration of such inflammatory cells as macrophages, CD4+ T cells and monocytes into sciatic nerve tissues and less demyelination than wild-type mice. Moreover, the CD28-deficiency led to reduced production of specific anti-P0 peptide 180-199 antibodies compared with wild-type mice. Evidently, CD28 is required for interaction with B7 to regulate the activation of T and B cells that initiates development of EAN.     

Rho激酶抑制剂对OX40及其配体mRNA在实验性变态反应性神经炎中表达的影响

目的 研究Rho激酶(ROK)抑制剂对OX40及其配体(OX40L)mRNA在实验性变态反应性神经炎(experimental allegic neuritis,EAN)大鼠坐骨神经、脾脏、外周血和淋巴结中表达的影响.方法 54只Lewis大鼠随机分为EAN模型组、EAN+ROK抑制剂干预组和完全弗氏佐剂对照(CFA)组.分别在免疫后第9、17、26天处死动物,取其坐骨神经根、脾脏、外周血单个核细胞和淋巴结,采用逆转录PCR(RT-PCR)技术检测OX40和OX40L mRNA在各组织的表达水平.结果 EAN+ROK抑制剂组大鼠OX40 mRNA在坐骨神经中第9、17、26天的表达分别为0.266±0.031、0.298±0.024和0.113±0.018;在淋巴结中第9、17、26天的表达分别为0.453±0.030、0.496±0.100和0.220±0.016;OX40L mRNA在坐骨神经中第9、17、26天的表达分别为0.247±0.018、0.298±0.026和0.165±0.013;在淋巴结中第9、17、26天的表达分别为0.283±0.027、0.306±0.011和0.161±0.012.与EAN组比较,OX40和OX40L mRNA的表达明显降低(t=2.24～4.89,P＜0.05),坐骨神经炎性细胞浸润和脱髓鞘减轻.CFA组大鼠无症状.结论 ROK抑制剂可以减轻EAN发病程度,抑制OX40/OX40L的表达可能是其作用机制之一.     

CD4 and CD8 T cells,but not B cells,are critical to the control of murine experimental autoimmune neuritis

Experimental autoimmune neuritis (EAN) is a T cell-mediated autoimmune disease of the peripheral nervous system that duplicates the clinical, pathological, and electrophysiological features of Guillain-Barré syndrome in humans. However, the molecular pathogenesis of EAN remains controversial. Therefore, for this study, we induced EAN with P0 protein peptide 180-199 in CD4(-/-), CD8(-/-), CD4(-)8(-), and B cell knockout (microMT) mice to further investigate the roles of these cells in EAN. Our results showed that the severity of clinical signs and histopathological manifestations of EAN and the T cell response to P0 peptide 180-199 in CD4(-/-) mice were significantly lower than those in their wild-type counterparts. CD8(-/-) mice also had a milder clinical course, less histopathological change, and a diminished T cell response to P0 peptide 180-199. However, more severe clinical and histopathological manifestations, a stronger T cell response to P0 peptide 180-199, and enhanced IFN-gamma production in the spleen were observed in the EAN of CD4(-)8(-) and microMT mice, but these were not obviously different from those of wild-type mice. Levels of IgG production were similar in sera from CD4(-/-), CD8(-/-), and CD4(-)8(-), and wild-type mice. These findings suggest that the induction and control of murine EAN are dependent on both CD4(+) and CD8(+) T cells and that B cells apparently do not perpetuate the related inflammatory demyelination.     

Suppression of autoimmune neuritis in IFN-gamma receptor-deficient mice

Experimental autoimmune neuritis (EAN) is an animal model of the human disease Guillain-Barré syndrome. In this autoimmune inflammatory disease, CD4(+) T cells mediate demyelination in the peripheral nervous system (PNS). Infiltrating macrophages and T cells as well as cytokines like interferon (IFN)-gamma are intimately involved in causing pathogenic effects. To investigate the role of IFN-gamma in cell-mediated EAN, IFN-gamma receptor-deficient mutant (IFN-gammaR(-/-)) C57BL/6 mice and corresponding wild-type mice were immunized with P0 peptide 180-199, a purified component of peripheral nerve myelin, and Freund's complete adjuvant. IFN-gammaR(-/-) mice exhibited later onset of clinical disease. The disease was also less severe than in wild-type mice. Fewer IL-12-producing but more IL-4-producing cells were found in sciatic nerve sections from IFN-gammaR(-/-) mice than from wild-type mice on day 24 postimmunization, i.e., at the peak of clinical EAN. At the same time, IFN-gammaR(-/-) mice had less infiltration of inflammatory cells, including macrophages, CD4(+) T cells, and monocytes, into sciatic nerve tissue and less demyelination. However, numbers of IFN-gamma-secreting cells from the spleen were significantly augmented in the IFN-gammaR(-/-) mice, reflecting a failure of negative feedback circuits. The IFN-gammaR deficiency did not affect the production of anti-P0 peptide 180-199-specific antibodies. These results indicate that IFN-gamma contributes to a susceptibility for EAN in C57BL/6 mice by promoting a Th1 cell-mediated immune response and suppressing a Th2 response.     

Dominance of autoreactive T cell-mediated delayed-type hypersensitivity or antibody-mediated demyelination results in distinct forms of experimental autoimmune neuritis in the Lewis rat

The role of anti-myelin antibodies in the pathogenesis of experimental autoimmune neuritis (EAN) induced in the Lewis rat by immunization with peripheral nerve myelin has been assessed. Passive transfer with lymph node cells (LNC) or purified serum immunoglobulin from rats with EAN was employed to directly measure the contribution of B cells and anti-myelin antibodies to demyelination and disease. Lewis rats with EAN transferred by LNC or purified serum immunoglobulin from EAN donors in conjunction with a low dose of P2-specific CD4+ T cells demonstrated profound histopathological and neurophysiological evidence of demyelination during disease. In contrast, the classical adoptive transfer model of EAN in the Lewis rat induced by the injection of P2-specific CD4+ T cells was characterized by histopathological and neurophysiological evidence of axonal dysfunction and degeneration with limited demyelination. These findings demonstrate that the synergistic action of T cells and anti-myelin antibodies mediating demyelination or purely T cell mediated axonal dysfunction and degeneration are distinct pathways by which a specific autoimmune response in the peripheral nervous system can cause neurological disease.     

Inflammation and proinflammatory cytokine production,but no demyelination of facial nerves,in experimental autoimmune neuritis in Lewis rats

Experimental autoimmune neuritis (EAN) is a CD4⁺ T cell-mediated, inflammatory demyelinating disease of the peripheral nervous system (PNS) that serves as a model for Guillain–Barré syndrome (GBS) in humans. The facial nerve paralysis is relatively commonly found in GBS patients. Here, EAN was established in Lewis rats by immunization with P2 peptide 57–81, a purified component of peripheral nerve myelin, and Freund's complete adjuvant (FCA). To study whether the facial nerves are involved in the pathogenic process during the EAN course, we observed the clinical and pathological changes as well as cytokine production in facial nerves on Day 14 postimmunization (p.i.), i.e. at height of clinical EAN. As a result, all rats immunized with P2 peptide 57–81 developed severe EAN on Day 14 p.i., but none of the rats manifested clinical signs of facial nerve paralysis. Additionally, only mild inflammatory cell infiltration and proinflammatory cytokine, interferon-γ (IFN-γ) and tumour necrosis factor (TNF-) production as well as devoid demyelination were seen in facial nerves of the EAN rats. On the contrary, severe inflammation and demyelination as well as upregulated IFN-γ and TNF- production were observed in sciatic nerves of the same EAN rats. The underlying mechanism for the difference of the local manifestation of the disease process of EAN remains to be resolved.     

Dual role of B cells with accelerated onset but reduced disease activity in P0106–125-induced experimental autoimmune neuritis of IgH0/0 mice

The role of B cells in autoimmune-mediated diseases of the peripheral nervous system was studied in experimental autoimmune neuritis (EAN) in B cell deficient IgH^0/0 C57BL/6J mice having been immunized with P0_106–125 peptide. Compared to coisogenic IgH^+/+ mice, onset of EAN was accelerated [100% disease incidence at day 9 post immunization (p.i.) vs. day 15 p.i.]. At day 9 p.i., numbers of P0_106–125-specific interferon (IFN)-γ-producing CD4⁺ T cells were increased, while IL-10 mRNA and production were decreased in IgH^0/0 mice. Beyond day 9 p.i., declining disease activity and a significant reduction of maximal disease activity were correlated with significantly reduced numbers of IFN-γ-producing CD4⁺ T cells in IgH^0/0 mice as compared with IgH^+/+ mice. Correspondingly, neuropathology demonstrated only mild axonal damage, while demyelination and dying back axonopathy with spinal cord motor neuron apoptosis were absent. Thus, depending on the stage of EAN, B cells play a dual, i.e. suppressive and enhancing, role during induction and at height of EAN, respectively. The combined interaction of B cells as well as CD4⁺ and CD8⁺ T cells is required for the development of EAN.     

Enhancement of acute phase and inhibition of chronic phase of experimental autoimmune neuritis in Lewis rats by intranasal administration of recombinant mouse interleukin 17: potential immunoregulatory role

Experimental autoimmune neuritis (EAN) is a CD4(+) T-cell-mediated demyelinating disease of the peripheral nervous system (PNS). We examined the effect of recombinant mouse interleukin 17 (rmIL-17) on chronic EAN induced in Lewis rats by inoculation of P2 57-81 peptide in Freund's complete adjuvant. Animals were treated nasally for 6 days with either 0.1 or 0.9 microg/rat/day rmIL-17 from the onset of neurological signs, i.e., days 9 to 14 postimmunization (p.i.). Prolonged follow-up demonstrated a chronic course in control and rmIL-17-treated rats. Treated rats had more severe disease initially (days 18-36 p.i.) with a stronger enhancing effect observed with the higher rmIL-17 dose. At day 19 rmIL-17-treated rats showed increased infiltration of inflammatory cells into the sciatic nerve, more severe demyelination, augmented proliferation of regional lymph node cells, and increased serum levels of tumor necrosis factor-alpha. After the initial phase of disease enhancement the IL-17-treated EAN rats improved gradually and ultimately recovered completely, whereas the control EAN rats remained affected until the end of the observation (day 120 p.i.). The lower dose of rmIL-17 induced an earlier recovery from clinical deficits than the higher one. The results indicate that IL-17 plays an immunoregulatory role in chronic EAN which could have implications for immunomodulatory treatments of chronic autoimmune disease of the PNS.     

Cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) blockade enhances incidence and severity of experimental autoimmune neuritis in resistant mice

Experimental autoimmune neuritis (EAN), an autoimmune inflammatory demyelinating disease of the peripheral nervous system, represents an animal model of the human Guillain-Barré syndrome. EAN can be induced by active immunization in several animals, including Lewis rats. In contrast, most strains of mice including the widely used C57BL/6 (B6) strain are reputedly resistant to the induction of EAN. In the present study, we demonstrate that in B6 mice, anti-CTLA-4 monoclonal antibody administration in conjunction with immunization with the P0 protein derived peptide 180-199 can induce clinical and pathological definite EAN. Upregulating effects of CTLA-4 blockade on initial and ongoing EAN are demonstrated. CTLA-4 blockade augmented cellular infiltration and enhanced demyelination in the target organ sciatic nerves as well as increased T cell proliferation in lymph node cells. Moreover, serum levels of IFN-gamma and IL-4 were increased. Thus, manipulation of CTLA-4/B7 costimulatory pathway by CTLA-4 blockade can promote autoreactivity and break the relative tolerance to peripheral autoantigen P0 in resistant B6 mice.     

P0 protein peptide 180-199 together with pertussis toxin induces experimental autoimmune neuritis in resistant C57BL/6 mice

The C57BL/6 mice strain is known to be reputedly resistant to induction of experimental autoimmune neuritis (EAN), an animal model of Guillain-Barré syndrome in human by bovine peripheral myelin (BPM), and P2 protein or the P2 protein peptide 57-81. The P0 peptide 180-199 is a stronger neuritogenic antigen than the P2 peptide 57-81. We found that this synthetic peptide induced both clinical and pathological characteristics of an acute monophasic EAN in C57BL/6 mice. Only male mice were more sensitive to EAN induction with the P0 peptide 180-199. Intravenously administrated pertussis toxin (PT) had an adjuvant effect that increased the incidence of P0 peptide 180-199-induced EAN as well as the inflammation and demyelination in the peripheral nerves. Spontaneous and P0 peptide 180-199 stimulated proliferation of peripheral T-cells were enhanced by PT-treatment as well. The enhancing effect was lower before onset of the disease (Day 6 post immunization) (p.i.) as compared to the early phase of the disease (Day 22 p.i.). Thus, P0 peptides together with PT are able to break tolerance to myelin in C57BL/6 mice.     

Responsiveness to P2 of blood- and cauda equina-derived lymphocytes in experimental allergic neuritis in the Lewis rat: preliminary characterisation of a P2-specific cauda equina-derived T cell line

Experimental allergic neuritis (EAN) was induced in Lewis rats by immunisation with bovine spinal root myelin. Neurological signs appeared on day 12 and persisted for 10-15 days. A transient protein P2-specific proliferative response of circulating mononuclear cells was detected on days 10 and 14 after immunisation but not on days 17 and 35. Mononuclear cells recovered from cauda equina infiltrates on days 14 and 17 showed greater responsiveness to P2 than circulating cells. A P2-specific, interleukin-2-dependent T cell line has been developed from cauda equina (CE)-derived lymphocytes. In adoptive transfer experiments this cell line did not induce EAN but did protect normal recipients from actively induced EAN.     

T cell vaccination does not induce resistance to experimental autoimmune neuritis.

The effectiveness of T cell vaccination was analyzed in experimental autoimmune neuritis (EAN) that can be induced by immunization with bovine P2 protein or a peptide representing the amino acids 53-78 of P2 (P2 53-78). Lewis rats were vaccinated with glutaraldehyde-fixed lymph node cells which had been primed in vivo with P2 protein or P2 53-78 and had been activated in vitro with concanavalin A. Vaccinated animals were not protected from EAN induced by immunization with P2 protein in complete Freund's adjuvant (CFA). In a second set of experiments Lewis rats were vaccinated with irradiated or fixed P2-specific T cell lines of different specificity and neuritogenicity and were subsequently challenged with P2 53-78 in CFA. Likewise, severity of P2 53-78-induced EAN was not different between naive and T line-vaccinated groups. In spleens of vaccinated animals a substantial suppressive activity was demonstrated which was positively correlated with a weak anti-ergotypic response of these spleen cells. The fact that development of actively induced EAN was not prevented or even mitigated by T cell vaccination, in spite of an apparent vaccination-induced response to and on T lymphocytes, suggests that protection from disease is not readily induced in every autoimmune disease model.     

Apolipoprotein E deficiency enhances the antigen-presenting capacity of Schwann cells

Apolipoprotein E (apoE) has immunomodulatory properties and has been implicated in the pathogenic mechanism of autoimmune diseases. Previously, the authors found that apoE deficiency increased the susceptibility to experimental autoimmune neuritis (EAN), an animal model for human Guillain-Barré syndrome. To further elucidate the mechanism behind apoE deficiency exacerbating EAN, the authors investigated the role of major target and important antigen-presenting cells of the peripheral nerve system, Schwann cells (SCs), in apoE knockout mice. Treatment of apoE deficient SCs with recombinant mouse interferon-gamma and lipopolysaccharide resulted in higher MHC-II and CD40 expression as compared with normal SCs derived from wild-type mice. The increased MHC-II and CD40 expression on SCs was accompanied by lower levels of intracellular IL-6 production within SCs of apoE deficiency, which is confirmed by the neutralization with anti IL-6 antibody. The increased antigen-presenting capacity of apoE deficient SCs was further explored by enhancement of T cell proliferation co-cultured with P0 peptide 180-199 specific T cells derived from EAN mice immunized with the P0 peptide. In conclusion, apoE may protect mice from EAN and probably also from chronic inflammatory demyelinating polyneuropathy by affecting the antigen-presenting function of SCs via influence of IL-6 production.     

Neutralizing antibodies to IL-18 ameliorate experimental autoimmune neuritis by counter-regulation of autoreactive Th1 responses to peripheral myelin antigen

Experimental autoimmune neuritis (EAN) is a demyelinating disease of the peripheral nervous system (PNS). This acute inflammatory disease is mediated by CD4+ T cells and bears significant similarities to the Guillain-Barré syndrome of humans. In the present study, we investigated the function of IL-18 in T cell-mediated autoimmunity of EAN in mice induced by P0 peptide 180-199 and Freund's complete adjuvant. Our data indicate that in 2 different therapeutic regimens, anti-IL-18 monoclonal antibody (mAb) effectively ameliorates the clinical and pathological signs of EAN. The suppression is associated with reduced inflammatory cell infiltration into the PNS and an insufficiency of autoreactive Th1 cells, as reflected by a reduced mononuclear cell proliferation and IFN-gamma-secretion in the spleen. Increased numbers of IL-4 expressing cells and decreased numbers of IFN-gamma and TNF-alpha expressing cells were found in the PNS. Our results suggest that shifting the Th1/Th2 balance towards Th2 cells may be one mechanism underlying EAN suppression by anti-IL-18 mAb. In addition, anti-IL-18 mAb treatment reduced anti-P0 peptide 180-199 autoantibody responses, which may also contribute to EAN suppression. We conclude that endogenous IL-18 plays a critical role in the pathogenesis of autoimmune demyelinating disease of the PNS and that IL-18 antagonists may provide a new therapy for these diseases.     

Myelin basic protein specific T-helper cells induce experimental anterior uveitis

Immunopathological changes in the eyes were examined in Lewis rats after active and passive induction of experimental autoimmune encephalomyelitis (EAE) with myelin basic proteins (MBP) at various stages of EAE. The onset of anterior uveitis (AU) coincided with hind limb paralysis, but uveitis persisted after clinical signs of EAE had subsided. A mild form of uveitis was characteristic for the majority of rats. The changes within the iris and ciliary body consisted of an accumulation of inflammatory cells lining the anterior surface of iris, the trabecular meshwork, and, in some cases, within the ciliary body and the aqueous humor. A similar histopathological picture was observed when rats were injected with the secondary encephalitogenic determinant for Lewis rats, MBP peptide 87–99. Flow cytometry analysis of T cells from the anterior segment of the inflamed eyes after immunization with MBP revealed the presence of CD4⁺ cells exclusively expressing Vβ8.2 and OX-40 markers. Our data suggest that MBP are encephalitogenic and uveitogenic in Lewis rats and that the Vβ8.2-positive T cells in the eye represent encephalitogenic T cells. Many of those T cells were distributed in the iris and the anterior chamber. These findings indicate that these MBP-specific T cells may play a critical role in EAE as well as in AU. © 1996 Wiley-Liss, Inc.     

Th1-like cell responses to peripheral nerve myelin components over the course of experimental allergic neuritis in Lewis rats

Experimental allergic neuritis (EAN) is a T cell-mediated animal model of Guillain-Barré syndrome characterized by inflammation and demyelination of peripheral nerves. EAN can be induced by immunization of rats with bovine peripheral nerve myelin (BPM) or the myelin proteins P2 or PO, but the extent of T cell responses over the course of EAN is incompletely defined. We studied the T cell responses to these proteins and the glycolipid GM1 by enumerating T helper type 1 (Th1)-like cells secreting interferon-γ (IFN-γ) after short-term culture of mononuclear cells (MNC) in presence of antigen. Already 7 days post immunization (p.i.) with BPM and before onset of clinical EAN, lymph nodes contained elevated levels of P2 responsive T cells. At the height of EAN on day 14 p.i. and during recovery, T cell levels responding to BPM, PO and GM1 were also elevated. The same temporal profiles and specificities were registered for antigen reactive spleen MNC. The results implicate that Th1-like cells with multiple specificities including the glycolipid GM1 occur at increased levels in lymphoid organs in EAN rats, and that IFN-γ may be an important effector molecule in the induction of nerve damage.     

重症肌无力患者CD40配体表达的信号传导途径初步探讨

目的研究重症肌无力(MG)患者CD40配体(CD40L)的表达,探讨MG患者CD40L表达的信号传导途径.方法研究对象为急性期MG患者13例.分离血中单个核细胞,分组用刺激剂刺激进行单个核细胞培养(1)纯培养组不加任何刺激剂进行细胞培养;(2)PMA组用PMA和A23187刺激;(3)PHA组用PHA刺激;(4)BLM组加PKC抑制剂BLM后再加PHA刺激培养.培养后用流式细胞仪检测CD40L阳性细胞率及RT-PCR法检测单个核细胞CD40L mRNA表达.结果MG急性期BLM组CD40L阳性细胞率和CD40L mRNA与纯培养组差异无显著性(P＞0.05),而显著低于PMA组和PHA组(P＜0.01).结论在MG中,CD40L的表达可能依赖于PKC活性介导的T细胞活化途径.