SLE发病的免疫机理

系统性红斑狼疮(SLE)是全身多系统受累的、非化脓性炎症的胶原—血管性或结缔组织疾病,是由多种自身抗体形成免疫复合物,沉积多脏器而造成损伤的自身免疫病,其发病涉及复杂的免疫机理。近年来通过动物实验及临床研究,对本病的了解已大     

口服耐受机制和对自身免疫性疾病治疗的研究进展

ｅｌｌｓ等 ( 1 91 1 ) [1 ] 首次描述了口服耐受现象 ,他们发现预先给豚鼠口服鸡蛋白可防止后来对该蛋白的全身性过敏反应。Ｃｈａｓｅ( 1 946) [2 ] 发现预先给豚鼠口服接触性致敏原二硝基氯苯 (ｄｉｎｉｔｒｏｃｈｌｏｒｏ-ｂｅｎｚｅｎｅ) ,可使动物减少对其皮肤接触性过敏反应。Ｎａｇｌｅｒ-Ａｎｄｅｒｓｏｎ等[3] 和Ｔｈｏｍｐｓｏｎ等[4] ( 1 986)首次将口服耐受用于自身免疫性疾病的实验研究。针对自身抗原的免疫无反应状态称为自然耐受 (ｎａｔｕｒａｌｔｏｌｅｒａｎｃｅ)或自身耐受 (ｓｅｌｆ-ｔｏｌｅｒａｎｃｅ) ;针对外源性…     

CD4+调节性T细胞与自身免疫性甲状腺疾病

调节性T细胞(Regulatory T cells,Treg)在调节机体免疫系统对自身抗原的免疫应答中起重要作用.在人类和动物实验中已发现Treg数量和功能缺陷与多种自身免疫病的发生有关,但目前对其作用机制尚未完全阐明.     

多发性硬化病人的白细胞移动抑制试验

国外学者通过实验研究认为,多发性硬化(MS)是一种与病毒和遗传结构有关的,由细胞介导的中枢神经系统自身免疫性疾病。但国内尚未见有关报导。本实验选用简单、可靠的体外细胞免疫检测方法一白细胞游走抑制试验(LMIT)进行了研究。首先根据Desbler和Kies介绍的方法,从人脑提取髓磷硷性蛋白(MBP),通过氨基酸分析和动物免疫证明本室提取的BP具有致脑炎抗原决定簇和诱导EAE的生物学效应。然后应用依据新宫正久的毛细管法稍加改进的直接毛细管玻片法进行实验。     

杂交瘤技术中的体外培养免疫法

杂交瘤技术的一个明显缺点就是依赖对动物的免疫。通过适当的免疫方法去获取大量活化的、抗原特异性的B淋巴细胞,以此作为亲代细胞与骨髓瘤细胞相融合。经典的免疫动物的方法一般需要毫克量的抗原和数周的免疫时程。这种对动物免疫的依赖性及免疫方法上的缺点给杂交瘤技术的广泛应用带来了一定的局限性。首先,开展人—人杂交瘤技术就难以实行对人体进行免疫,然后取其淋巴细胞(如脾脏、淋巴结、外周血)进行融合,其次,制备抗“自身”成份的单克隆抗体时,“自身”抗原在     

用我国海域电鳐电器官提取的N_2AchR粗提物建立大鼠EAMG模型

重症肌无力 (myastheniagravis,MG )是由烟碱型乙酰胆碱受体 (N2 AchR )抗体介导的针对神经肌肉接头处突触后膜上N2 AchR进行破坏的一种自身免疫性疾病。目前公认的MG动物模型是用电鳐 (Torpedocalifornia )发电器官提取、纯化的N2 AchR作为抗原免疫动物 ,建立实验性自身免疫性重症肌无力 (EAMG )模型 ,进行MG发病机制研究。但N2 AchR纯化需用眼镜蛇神经毒素 ,造价高 ,且制备复杂。国内建立EAMG模型 ,进行MG机制研究所用纯化的N2 AchR大多是国外同行馈赠所得 ,只能做少量动物实验。国内尚缺乏进行药效学研究的大样本的EAMG模…     

一种长效的河豚毒素抗毒疫苗的实验研究

目的：河豚毒素(TTX)是高毒神经性毒素，目前无特效解毒药。为开发TXX的化学抗毒疫苗而开展本研究。方法：以中国鲎血蓝蛋白(TTX)为载体，通过甲醛将河豚毒素与载体蛋白连接，制成人工抗原(TTX—TTH)并免疫Balb/C小鼠。定期监测血中抗体质量，并定时作TTX攻毒实验，检验疫苗的时效性。结果：小鼠对小分子半抗原TTX的抗体反应有其自身规律。免疫鼠于末次免疫后定时ip TTX，每次LTD，一年内累计攻毒15次，抗毒基本有效；至动物衰老期部分有效；最长测试时间达24个月(累计26次)时，1／4动物抗毒存活，实验疫苗长期有效。结论：研制的TTX的实验疫苗可有效预防TTX的攻毒，效价高且持久。免疫预防是对抗河豚毒素中毒很有希望的途径。     

T细胞在器官特异性自身免疫疾病中的作用

近年来,从实验诱发的自身免疫性疾病的动物体内分离自身反应性T淋巴细胞已获成功,并可在体外进行纯培养。用这些T细胞可将疾病传递给健康动物,并且从患病的动物体内又可分离同样的T细胞,继续进行传递。自身免疫性淋巴细胞的致病作用符合     

流行性出血热特异性iRNA转移抗病毒免疫的初步研究

<正> 较多的研究表明流行性出血热(EHF)患者常伴有免疫功能紊乱,故提高、改善其特异性免疫水平可望成为有效的治疗方法之一。iRNA是一种有前途的特异性免疫触发、增强剂,它可以将供体的特异性免疫传递给未经免疫的动物。本文通过流行性出血热病毒特异性免疫核糖核酸在实验动物间传递特异性免疫活性的观察,为临床应用和进一步阐明其作用机制提供理论及实验依据。     

多沙唑嗪干预对α_1肾上腺素能受体抗体免疫糖尿病大鼠心肌的保护作用

<正>目的:探讨多沙唑嗪干预对抗α1肾上腺素能受体自身抗体(抗α1R-Ab)阳性糖尿病(DM)大鼠心肌转化生长因子β1(TGF-β1)表达和心肌胶原纤维含量的影响及其心肌保护作用的可能机制。方法:DM模型大鼠采用α1R-Ab注射液(100μg/100g体重)于实验第0、4、8、12、16周尾静脉注射,建立α1R-Ab免疫的DM大鼠模型。实验动物随机分为A组(DM对照组)、B组(DM+多沙唑嗪治疗组)、C组(DMα1R-Ab免疫组)、D组(DMα1R-Ab免疫+多沙唑嗪治疗组)。B组和D组给予多沙唑嗪0.36mg/Kg/天灌胃;A组和C组同时给予等体积生理盐水灌胃。16周后处死大鼠。     

Regulatory circuits in autoimmunity: recruitment of counter-regulatory CD8+ T cells by encephalitogenic CD4+ T line cells

In this study, pretreatment of Lewis rats with a syngeneic encephalitogenic T cell line (S1) was found to be able to constantly induce resistance to the subsequent induction of transferred experimental autoimmune encephalomyelitis (tEAE). This treatment was capable of protecting recipient animals for at least 2-4 months. Here we show an enhanced suppressor T(anti-S1) cell activity, which can be readily detected in the lymphoid organs of animals which recovered from S1-induced tEAE, or from rats pretreated with attenuated (irradiated, fixative treated or water-lysed) S1 cells. Anti-S1 cells, which uniformly express the CD8 phenotype, were selectively stimulated to grow and expand into lines by confronting primed lymphoid cells with irradiated S1 cells in culture. The proliferative response of anti-S1 cells was independent of myelin basic protein and antigen-presenting cells, and the responses against unrelated encephalitogenic T cell lines were minimal. It was also found that none of the monoclonal antibodies tested (including CD8 and MHC class I antigen-specific antibodies) was able to block S1/anti-S1 interactions. These cells are functionally suppressive to the proliferation of S1 cells in vitro, are specifically cytolytic directed against the EAE-inducing S1 cells and are able to antagonize encephalitogenic capacity of S1 cells in vivo. In vivo elimination of the CD8+ T subset from Lewis rats, using a combined treatment of thymectomy and OX-8 antibody injection before the initial cell transfer, totally blocked the induction of resistance. Our experiments document that induction of functionally active suppressor T cells is responsible for the induced resistance observed in tEAE.     

Recovery mechanisms from experimental allergic encephalomyelitis in rats: analyses by using encephalitogenic T cell line

The recovery mechanism of acute experimental allergic encephalomyelitis (EAE) in Lewis rats was studied by using an encephalitogenic T cell line specific for myelin basic protein. Antigen-activated line cells were highly encephalitogenic, but unstimulated line cells were not encephalitogenic. The activated line cells returned to the unstimulated state in a few days in culture medium without antigen. This decline of proliferative and encephalitogenic activities of the activated line cells was also observed even if the activated line cells were continuously stimulated with the antigen. In addition, rats during the convalescent stage from acute EAE showed only mild clinical signs of EAE even by transfer of almost a lethal dose of activated line cells. Thus, self-limiting capacity of autoaggressive cells and attenuation of effector cell function during the convalescent stage seem to be involved in the recovery mechanism of EAE.     

Immune regulation in self tolerance: functional elimination of a self-reactive, counterregulatory CD8+ T lymphocyte circuit by neonatal transfer of encephalitogenic CD4+ T cells lines.

Transfer of encephalitogenic, CD4+ T lymphocyte lines into syngeneic adult Lewis rats not only leads to the development of experimental autoimmune encephalomyelitis (EAE), but, in addition, to the expansion of counterregulatory, CD8+ T lymphocyte clones which are able to lyse specifically the encephalitogenic T cells in vitro and to neutralize their encephalitogenic capacity in vivo. In striking contrast, in neonatal rats, which still lack myelin (autoantigens), injection of the same encephalitogenic lines neither mediates EAE, nor confers protection in later life against the myelin-specific T cells. In fact, this treatment results in the life-long functional elimination of counterregulatory, clonotypic CD8+ T lymphocytes, which cannot even be reinduced by repeated injections of the relevant CD4+ T line. These data seem to point to a self-protective T cell control mechanism which is developed within the immune system prior to, and thus independent of the appearance of the appropriate self antigen.     

Anergy induction in encephalitogenic T cells by brain microvessel endothelial cells is inhibited by interleukin-1

Experimental autoimmune encephalomyelitis (EAE) is an inflammatory disease of the central nervous system (CNS) which can be induced, in susceptible strains like Lewis rats, by transfer of activated myelin basic protein (MBP)-specific CD4⁺ T lymphocytes. The role of cerebral endothelium in the onset of EAE, with regard to adhesion, activation and infiltration in the CNS of encephalitogenic T lymphocytes, is not fully understood. When pretreated by interferon-γ, the immortalized Lewis rat brain microvessel endothelial (RBE4) cells expressed major histocompatibility complex class II molecules and stimulated MBP-specific proliferation and cytolytic activity of the syngeneic encephalitogenic T cell line, designated PAS. However, RBE4-stimulated PAS lymphocytes subsequently entered an unresponsive state, known as anergy. When inoculated in syngeneic animals, anergic PAS cells, although still cytotoxic, failed to induce EAE, and no cell infiltration was detectable within CNS. The addition of interleukin-1β (IL-1β) during MBP presentation by RBE4 cells prevented T cell anergy induction, and maintained T cell encephalitogenicity, although PAS cells stimulated in these conditions caused delayed and attenuated clinical signs of EAE, with only discrete inflammatory lesions in the CNS, compared with EAE induced by PAS cells fully activated by thymic cells. Altogether, our results indicate that MBP presentation by brain microvessel endothelial cells to encephalitogenic T cells induces T cell anergy and loss of pathogenicity. In addition, IL-1β co-stimulation of T cells prevents anergy induction in vitro and at least partially maintains encephalitogenicity in vivo.     

Protection from experimental allergic encephalomyelitis by application of a bacterial superantigen.

Certain bacterial and viral T cell stimulating proteins ('superantigens') are known to be very potent activators of T cells with certain V beta receptors. When applied in vivo these molecules induce anergy in those T cells responding to them. In this study we have investigated the influence of staphylococcal enterotoxins (SE) on myelin basic protein (MBP)-specific T cells in Lewis rats. As MBP-specific T cells in rats belong exclusively to the V beta 8.2+ CD4+ subset, the induction of experimental allergic encephalomyelitis (EAE) allows for an estimation of the functional state of the respective V beta-bearing T cells after enterotoxin-induced activation. In vitro, various MBP-specific T cell lines showed a strong selective proliferative response to staphylococcal enterotoxin E (SEE) but not to other SE. The in vitro activation by SEE induced encephalitogenic potential in these cells. After application of SEE to Lewis rats the susceptibility to induction of EAE was completely abrogated. Such SEE-treated and MBP-challenged rats did not exhibit any signs of disease and their T cells did not respond to MBP in proliferation tests. This abrogation of EAE was only found with a superantigen capable of interacting specifically with V beta 8.2+ T cells. Superantigen-mediated induction of unresponsiveness may have relevance for the analysis of pathogenetic mechanisms and for therapeutic considerations in certain T cell-mediated autoimmune diseases.     

Soluble antigen therapy induces apoptosis of autoreactive T cells preferentially in the target organ rather than in the peripheral lymphoid organs

The administration of soluble myelin proteins is an effective way of down-regulating the inflammation in the central nervous system (CNS) in experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis. To shed more light on the mechanism of this antigen-specific therapy, we determined the effect of the intraperitoneal (i.p.) injection of soluble myelin basic protein (MBP) on T cell apoptosis in the CNS and peripheral lymphoid organs of Lewis rats with EAE induced by inoculation with MBP and complete Freund's adjuvant. In particular we assessed the level of apoptosis of Vβ8.2⁺ T cells, which constitute the predominant encephalitogenic MBP-reactive T cell population in the Lewis rat. The daily i.p. injection of MBP for 3 days from the onset of neurological signs inhibited the further development of neurological signs of EAE. Using two-color flow cytometry we found that a single i.p. injection of MBP increased the level of apoptosis of the Vβ8.2⁺ T cell population in the CNS to 26.2 % compared to 7.4 % in saline-treated rats and 7.6 % in ovalbumin-treated rats. In contrast, treatment with MBP did not increase the level of apoptosis of the Vβ8.2⁺ population in the popliteal lymph node draining the inoculation site (1.4 %) or in the spleen (1.6 %) above that occurring in saline-treated rats (1.6 % and 1.1 %, respectively). Limiting dilution analysis revealed that the frequency of T cells reactive to the major encephalitogenic epitope, MBP_{72 – 89}, was decreased in the CNS but not in the popliteal lymphnode by this treatment. Three-color flow cytometry in MBP-treated rats demonstrated that CNS Vβ8.2⁺ T cells expressing Fas (CD95) and Fas ligand were highly vulnerable to apoptosis compared to Vβ8.2⁺ T cells not expressing these proteins. We conclude that the i.p. injection of MBP increases the spontaneously occurring Fas-mediated activation-induced apoptosis of auto reactive T cells in the CNS in EAE and that this contributes to the therapeutic effect of the injection.     

Propentofylline and Iloprost Suppress the Production of TNF-αby Macrophages but Fail to Ameliorate Experimental Autoimmune Encephalomyelitis in Lewis Rats

Intracellular cAMP levels can be elevated by activation of cAMP-generating adenylate cyclase (AC) or inhibition of cAMP-cleavage by phosphodiesterases. Elevation of intracellular cAMP levels in immune cells inhibits production of some Th1-cytokines, particularly TNF-α, and results mainly in downregu-lation of the immune response. Experimental autoimmune encephalomyelitis (EAE) of Lewis rats is a disease mediated by type 1 T helper lymphocytes and macrophages and serves as a model of multiple sclerosis. In EAE we therefore tested the immunomodulatory potency of an AC-activating, stable prosta-cyclin analogue, iloprost, and of a potent and non-selective inhibitor of phosphodiesterases, propentofylline, which also has neuroprotective properties.Preventive treatment of Lewis rats with propentofylline (2×10 or 12.5 mg/kg/d), iloprost (2×10 or 12.5 μg/kg/d), or both did not significantly ameliorate clinical or histological signs of EAE actively induced by immunization with myelin basic protein (MBP) in complete Freund's adjuvant. Furthermore, adoptive transfer EAE (AT-EAE), passively induced by injection of encephalitogenic MBP-specific Th1 lymphocytes, was not altered in its course by the combined application of iloprost (2×10 μg/kg/d) and propentofylline (2×20 mg/kg/d) starting on the day of cell transfer. In vitro assays demonstrated that iloprost strongly and propentofylline moderately inhibited the production of TNF-α by macrophages and that iloprost in vivo similarly suppressed TNF-α secretion, although this effect was limited to a few hours after a single injection. In contrast to macrophages, TNF-α production by antigen-activated encephalitogenic T helper line cells in vitro was completely resistant to modulation by these agents. In addition, the presence of iloprost, propentofylline, or both drugs during activation of the line cells in vitro did not impair their encephalitogenicity in vivo.The findings delineate immunomodulatory effects of both substances, particularly of iloprost, but fail to support a possible therapeutic role of these agents in autoimmune inflammation of the central nervous system.     

Immunoregulation of encephalitogenic MBP-NAc1-11-reactive T cells by CD4+ TCR-specific T cells involves IL-4, IL-10 and IFN-gamma

The generation of TCR transgenic (Tg) mice expressing a BV8S2 (Vbeta8 subfamily 2) chain specific for the encephalitogenic NAc1-11 region of MBP provides a unique system for evaluating the mechanisms involved in anti-TCR immunoregulation of EAE. In a previous study, we showed that vaccination with BV8S2 protein induced specific T cells that inhibited proliferation responses and encephalitogenic activity of MBP-reactive T cells in vitro, and resulted in a skewed production of Th2 cytokines by the MBP-reactive T cells. These data suggested that regulation of the encephalitogenic T cells was mediated by inhibitory cytokines rather than through a deletional mechanism. In the current study, we have employed the BV8S2 Tg mouse model to address the issue of which cytokines produced by anti-TCR-reactive T cells can regulate the function of encephalitogenic Th1 cells. Utilizing neutralizing anti-cytokine antibodies to reverse inhibitory effects of supernatants from BV8S2-specific T cells, we found that IL-4, IL-10, and to a lesser extent, IFN-gamma and TGF-beta, were the major regulatory cytokines responsible for inhibiting encephalitogenic activity, proliferation, and IFN-gamma secretion of MBP-NAc1-11-reactive Th1 cells. These results indicate that cytokine regulation is the major mechanism through which TCR specific CD4+ T cells regulate encephalitogenic and potentially other bystander Th1 cells.     

Characterization of brain-isolated rat encephalitogenic T cell lines

In the present study, we have isolated and characterized five myelin basic protein (MBP)-reactive T cell lines directly from the brains of Lewis rats during the early paralytic phase of experimental autoimmune encephalomyelitis (EAE). Each T cell line responded to the dominant encephalitogenic epitope spanning residues 68–88, and did not react against the conserved encephalitogenic epitope [MBP(87–99)] or the nonencephalitogenic MBP epitope [MBP(50–69)]. We determined the T cell receptor (TcR) β chain usage by polymerase chain reaction, DNA sequencing analysis and by generation of MBP-reactive hybridomas from one of the T cell lines (BT74). The results revealed that brain-infiltrating, MBP-reactive T cells freshly isolated early in the course of the disease exhibit TcR diversity.     

Heterogeneity of rat encephalitogenic T cells elicited by variants of the myelin basic protein (68–86) peptide

By immunizing Lewis rats with myelin basic protein (MBP) peptide variants derived from the major encephalitogenic epitope of guinea pig (MBP(68–88) and then isolating encephalitogenic T cells from these animals, we demonstrated that the variant peptides do not elicit the same encephalitogenic T cell subsets as those induced by the wild-type peptide or by intact MBP. Rather, the pathogenic T cells differed in clonal composition as reflected by their heterogeneous responses to a panel of variant peptides and by their T cell receptor usage. Thus, molecules mimicking the MBP(68–88) autoantigen can elicit pathogenic T cell subsets without necessarily cross-reacting with T cells specific for the original autoantigen. This suggests that a more clonally diverse group of pathogenic T cells might be involved in EAE than has been apparent from studies with intact MBP or its unaltered peptides.