首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
Experimental autoimmune encephalomyelitis (EAE) is a T cell-mediated autoimmune disease of the CNS and an animal model for the human demyelinating disease, multiple sclerosis. In the Lewis rat, myelin basic protein (MBP)-CFA-induced EAE is an acute monophasic disease from which animals recover fully, do not relapse, and develop a robust long-term resistance to further active reinduction of disease. In this paper, we report that rats recovering from MBP-CFA-induced EAE have significantly increased serum levels of reactive nitrogen intermediates indicative of increased NO production. These levels remain elevated after the recovery period and increase even further early after a rechallenge with MBP-CFA, and all animals are totally refractory to a second episode of disease. Oral treatment of rats with N-methyl-l -arginine acetate (l -NMA), beginning at peak disease on day 11 postimmunization, results in significant prolongation of disease and an alteration in the presentation of clinical symptoms from that of solely hind limb paresis/paralysis to severe fore limb involvement as well. Treatment of fully recovered rats with l -NMA 24 h before a rechallenge with MBP-CFA leads to decreased serum reactive nitrogen intermediate levels and results in a second episode of EAE in 100% of animals. Furthermore, l -NMA treatment of fully recovered rats in the absence of a rechallenge immunization leads to spontaneous relapse of disease.  相似文献   

2.
Monoclonal antibody W3/25, which recognizes rat T helper cells, was injected i.p. or i.v. into Lewis rats with clinical signs of experimental allergic encephalomyelitis (EAE). This treatment, which was given 12 or 13 days after inducing EAE by the injection of purified myelin basic protein, significantly affected the course of the disease in that treated animals recovered, on the average, in 2 days, whereas control animals exhibited signs of EAE for a minimum of 4 days. Two pan-T cell monoclonal antibodies given in similar dosage failed to affect the course of the disease.  相似文献   

3.
The encephalitogenic myelin basic protein (BP) was reported to be effective in preventing and suppressing the development of experimental allergic encephalomyelitis (EAE) when animals were treated before or after encephalitogenic challenge, respectively. In this report we show that pretreatment with 15 daily doses of 2.5 or 0.15 mg homologous BP (in IFA) failed to protect guinea pigs from subsequent challenge with encephalitogenic emulsion. Similarly, 15 daily injections of 1.0, 2.5, 5.0, or 10.0 mg guinea pig BP (in IFA) did not suppress development of or arrest ongoing EAE when the treatment was initiated on days 1, 4, 8, or 11 after an encephalitogenic challenge. The results show that over 50% of the treated animals developed hind leg paralysis (HLP), incontinence, or both, and the incidence of HLP was not altered significantly by a 10-fold increase in the amount of BP used for daily treatment. Further, all the treated and challenged animals developed histological lesions characteristic of disease. Treatment with BP delayed disease onset, prolonged the period of paralysis leading to recovery from HLP, and reduced both the prevelence of histological lesions as well as the incidence of death. It may be concluded that under these experimental conditions the administration of BP failed to protect from or suppress development of EAE.  相似文献   

4.
Guinea pigs injected with myelin basic protein (BP) in incomplete Freund's adjuvant (IFA) fail to develop experimental allergic encephalomyelitis (EAE) after challenge with BP in complete Freund's adjuvant (CFA). Such protected animals fail to manifest significant in vitro lymphocyte proliferative responses to BP 13 days after BP/CFA in comparison to animals with EAE. Other BP/IFA-BP/CFA animals develop significant albeit modest responses to BP 21 and 28 days after BP/CFA but do not develop EAE. There was little effect on the response to tuberculin (OT). Guinea pigs receiving only BP/IFA develop a modest transient reactivity to BP and no EAE. CFA alone after BP/IFA elicits a normal response to OT and has no effect on the response to BP.  相似文献   

5.
Guinea pig myelin basic protein (MBP) was inserted into phosphatidylserine liposomes and Lewis rats were injected by the intracardiac (ic) route with 75 microgram doses of MBP-liposomes according to various schedules. After challenge with 75 microgram guinea pig MBP in complete Freund's adjuvant, the rats were followed for clinical signs, were tested for delayed hypersensitivity (DTH) and lymphocyte transformation (LT) to MBP. The animals were sacrificed 30 days after challenge and the central nervous system tissue was examined for histological modifications. Rats treated with two injections of MBP-liposomes, 7 days before and 7 days after challenge, showed the highest degree of protection from clinical manifestations. Histological lesions were not significantly reduced. DTH reactions to MBP were all positive, regardless of treatment. LT assays were positive overall in only 50% of the animals tested. The response to rat MBP was significantly lower than to guinea pig MBP, especially in the groups treated with MBP-liposomes. Adoptive transfer of spleen cells from MBP-liposome-treated donors reduced the clinical scores of actively induced EAE in syngeneic recipients by 40-50%. These results suggest that at least one mechanism responsible for antigen-specific protection in EAE by MBP-liposomes operates through active suppression transferable by spleen cells.  相似文献   

6.
Experimental allergic encephalomyelitis (EAE) is an induced disorder in which an autoimmune response specific for myelin basic protein (BP) results in neural tissue destruction and acute paralysis. Lewis rats rapidly recover from induced paralysis and do not display any clinical manifestations of EAE following a second BP injection. The object of this study was to determine if immunologic recognition of encephalitogenic fragments of the BP molecule occurs during the induction, recovery, and resistance phases of EAE. Paralysis was induced in Lewis rats by a single injection of BP in complete Freund's adjuvant (CFA). The results indicate that macrophage migration inhibition in the presence of encephalitogenic BP fragments containing amino acid residues 43–88 and 68–88 is detectable during the paralytic stage of EAE, and also following recovery from clinical neurologic impairment. Although rats which had recovered were resistant to secondary BP-induced paralysis, macrophage migration inhibition in the presence of BP, or its encephalitogenic fragments, was detected after the second BP-CFA challenge. In order to assess humoral immunologic recognition, levels of serum antibody specific for the 43–88 BP fragment were determined. Specific antibody was not detected during the paralytic episode, but appeared upon recovery. Specific antibody was also detected following the secondary BP-CFA challenge. These data indicate that antigen-sensitive cells are present during the induction, recovery, and resistance phases of EAE in the Lewis rat. The mechanism which controls the activity of these cells in vivo has not been established.  相似文献   

7.
The durability of immunoprotection against experimental autoimmune encephalomyelitis (EAE) was assessed in guinea-pigs, using a standard protective inoculum (10 μg) of basic protein of myelin (BPM) in Freund's incomplete adjuvant. Protected animals withstood incrementally greater challenges with BPM in Freund's complete adjuvant, up to the massive dose of 10 mg. Protection was not readily overridden by challenge with either whole human brain or guinea-pig spinal cord, indicating that BPM is the major if not only encephalitogen in neural tissue. Protected animals, after encephalitogenic challenge, either developed no disease or a mild attenuated form of EAE; a few developed either chronic or relapsing types of EAE.Immunoprotection correlated with reduced cell-mediated immunity to BPM as judged by cutaneous reactions, but not with humoral antibodies to BPM as detected by radioimmunoassay (total antibody) or passive cutaneous anaphylaxis (IgG1 class); total and IgG1 antibody increased with repetitive encephalitogenic challenge. Whilst immunoprotection is related to functional changes in T cells, it remains uncertain whether there is potentiation of a class of suppressor T cells, or inhibition of a class of cytotoxic T cells, or both.  相似文献   

8.
Juvenile strain 13 guinea pigs were immunized with myelin basic protein (MBP) combined with galactocerebrosides (MBP + GC) or with total myelin lipids without GC [MBP + (TL-GC)] in CFA. Control animals received dinitrophenylated-ovalbumin (DNP-OA) in CFA, CFA or IFA alone. The animals injected with MBP + GC showed a higher rate of recovery from the first EAE episode (83%) than those treated with MBP + (TL-GC) (50%). With the exception of the group treated with IFA alone, all animals were refractory to EAE following rechallenge with MBP in CFA 90 days after the first exposure. The in vitro proliferative response to MBP, of peripheral blood lymphocytes (PBLs) derived from guinea pigs freshly sensitized to MBP in CFA, was drastically suppressed in the presence of PBLs from animals injected with MBP + GC. Upon transfer to normal syngeneic recipients, spleen cells from MBP + GC-treated animals completely suppressed the clinical and histological manifestations of EAE following recipient challenge with MBP in CFA. Cell-free supernatants from PBLs and spleen cells of strain 13 guinea pigs treated with MBP + GC inhibited lymphocyte proliferation to MBP, of allogeneic responder cells, and spleen cell supernatants completely suppressed the induction of EAE upon transfer to allogeneic recipients. Suppression could not be transferred with cells from other treated groups. These results suggest that animals immunized with MBP + galactocerebrosides in CFA develop suppressor cells that may be in part responsible for the recovery from the first EAE episode and for protection against rechallenge with MBP in CFA. Their cell-free supernatants act in an MHC-nonrestricted fashion. These results do not rule out an additional protective mechanism since all animals exposed to CFA were refractory to rechallenge despite lack of demonstrable suppressor cell activity.  相似文献   

9.
In previous experiments, we showed that administration of myelin basic protein (MBP) inserted into phosphatidyl-serine liposomes, to susceptible animals suppressed the clinical manifestations of both acute and chronic-relapsing EAE. In this report we compare the effectiveness of treatment with MBP-liposomes and with MBP-coupled syngeneic spleen cells in EAE protection. Lewis rats treated with 150 micrograms MBP-liposomes or with 160 micrograms (35 x 10(6] MBP-coupled spleen cells, given 7 days before and 7 days after encephalitogenic challenge were equally protected against clinical EAE, when compared to untreated controls. In addition to clinical protection, in vitro proliferative responses of lymphocytes from treated rats were significantly reduced, but delayed hypersensitivity (DTH) reactions remained unaffected. Proliferation of lymphocytes from MBP-sensitized donors was inhibited by the addition of spleen cells but not of lymph node cells from treated donors. The inhibitory effect was observed with spleen cells regardless of whether the donors were treated or not, was antigen nonspecific, and localized in a radio-resistant, adherent cell population. Adoptive transfers of spleen cells from treated donors, after a 48-hr in vitro incubation with concanavalin A, showed that the cells from donors treated with MBP-coupled spleen cells, but not with MBP-liposomes, suppressed the disease in recipients, following challenge with MBP-complete Freund's adjuvant (CFA). These results suggest that two distinct mechanisms operate in the protection by MBP-coupled cells and MBP-liposomes, respectively.  相似文献   

10.
Myelin basic protein-CFA-induced experimental autoimmune encephalomyelitis (EAE) in Lewis rats is an acute monophasic disease from which animals recover. In this model, spontaneous relapses do not occur and rats develop a resistance to further active reinduction of disease. Previously, we reported that oral administration of the NO synthase inhibitor N-methyl-L-arginine acetate (L-NMA) to recovered rats precipitated a second episode of disease in 100% of animals. Further studies now show that this second clinical episode is actually a chronic relapsing disease that persists for months. This occurs only in rats that have recovered from actively induced EAE and not in rats recovered from passively induced EAE, suggesting the need for a peripheral Ag depot to induce secondary disease. We have also determined that clinical signs of EAE in L-NMA-treated recovered rats do not appear until L-NMA treatment has stopped. This is despite the fact that, at the same time point, CNS inflammatory lesions in symptomless animals receiving L-NMA are qualitatively and quantitatively similar to those with severe disease symptoms from whom L-NMA treatment has been withdrawn. The latter animals have significantly higher levels of reactive nitrogen intermediates in the cerebrospinal fluid than the former group. This study examines the mechanism of reinduction of disease by L-NMA treatment, and the findings suggest a dual role for NO in regulation of pathology in EAE that is dependent on site and timing of NO production.  相似文献   

11.
The biological properties of the chymotrypsin-treated encephalitogenic basic protein are described. The basic protein, isolated from bovine spinal cord, was digested with chymotrypsin and filtered through Sephadex gel resulting in three distinct well-separated peaks starting at the void volume of the column. Tubes common to each peak were combined into Fractions I, II, and III, respectively. More than 90% of the original protein was recovered in the three fractions. Fraction II, representing 76% of the original protein, was nonencephalitogenic when tested in guinea pigs at 0.010-, 0.025-, and 0.500-mg doses emulsified in complete Freund's adjuvant. Guinea pigs immunized with Fraction II were protected from EAE when challenged with encephalitogenic emulsions. A critical dose of 1.0 mg completely protected the animals from disease, while partial protection was obtained with lower doses. In addition to producing circulating antibodies, animals sensitized with Fraction II, the encephalitogenic tryptophan peptide or the basic protein displayed a delayed-type hypersensitivity response when skin tested with either of the three antigens. The positive skin reactivity in animals sensitized with Fraction II was not followed by EAE during 5 months of observation. In contrast, animals sensitized with extracts from bovine tissues other than the central nervous system were not protected from disease when challenged with encephalitogenic emulsions.The main finding here reported is the prevention of EAE with nonencephalitogenic peptides derived from the parent EAE-producing protein. The peptides retain the ability to induce delayed-type hypersensitivity and provide antigens to study the role of delayed hypersensitivity in experimental allergic encephalomyelitis.  相似文献   

12.
In 2-mo-old Lewis rats immunized with bacterial lipopolysaccharides (LPS) precomplexed to guinea pig myelin basic protein (BP), the clinical and histologic manifestations of experimental allergic encephalomyelitis (EAE) were diminished compared with BP-treated controls. Similarly, in animals immunized with BP and challenged with BP-LPS at the same time or as long as 5 days after, the immunization with BP also inhibited the disease. That this capacity to reduce the incidence of BP-induced EAE is a unique property of LPS was suggested by the fact that other negatively charged molecules, such as DNA, RNA, and dextran sulphate, were not effective in inhibiting the clinical signs of EAE. After recovery from EAE induced by BP, some animals develop a recurrence of the disease if challenged with BP at appropriate intervals. However, after recovery from mild EAE induced by BP-LPS and after challenges with EAE-initiating BP antigens, secondary EAE was inhibited significantly.  相似文献   

13.
Adoptive transfer of experimental allergic encephalomyelitis (EAE) with splenic lymphocytes from Lewis rats sensitized to myelin basic protein (BP) was potentiated by incubation of the cells in vitro with concanavalin A (Con A). Spleen cells of donors which had recovered from EAE also transferred the disease readily after activation by this procedure. In contrast, the transfer of activity of lymph node cells was not altered. We conclude that during the course of EAE a population of T cells with immunologic memory for BP is generated and persists in the spleen. Incubation with Con A activates these cells and results in marked enhancement of their ability to transfer the disease.  相似文献   

14.
Intravenous administration of mouse myelin basic protein covalently coupled with chromic chloride to syngeneic spleen cells (MBP-SC) prevents the subsequent induction of experimental allergic encephalitis (EAE). Whereas 1 in 28 mice receiving MBP-SC developed EAE after immunization with mouse spinal cord homogenate (MSCH) and adjuvants, 16 out of 25 mice receiving ovalbumin-coupled spleen cells (OA-SC) had EAE following encephalitogenic challenge. The effect of administration of antigen-coupled spleen cells on in vitro proliferation responses is shown.  相似文献   

15.
1. Reactions between triphosphoinositide and the basic experimental allergic encephalitogenic (EAE) protein were examined in aqueous solution and in a biphasic solvent system (chloroform-methanol-water, 8:4:3, by vol.). 2. In the absence of salt an insoluble complex (I) is formed containing triphosphoinositide and EAE protein in proportions that represent complete neutralization of lipid and protein at the pH concerned. 3. In the presence of a low concentration (0.05m) of sodium chloride an insoluble positively charged complex (II) forms. It contains triphosphoinositide and EAE protein in a lower concentration ratio than complex I. This complex, which has a constant composition between pH7.5 and pH10, can take up additional micellar triphosphoinositide producing complex I, which can then be solubilized by excess of triphosphoinositide. 4. The complexes are dissociated by more concentrated sodium chloride solutions and low concentrations of calcium chloride, suggesting that they are largely stabilized by electrostatic bonds. The protein recovered after dissociation is immunologically active and has the same electrophoretic mobility as the original. 5. Water-insoluble ternary complexes containing triphosphoinositide, EAE protein and large amounts of phosphatidylcholine can be prepared. From these, chloroform-methanol (2:1, v/v) extracts only phosphatidylcholine. 6. An insoluble ternary complex of Ca(2+) ion, EAE protein and triphosphoinositide can be prepared by adding calcium chloride to a complex I preparation solubilized by excess of triphosphoinositide. 7. EAE protein will also form complexes with other acidic phospholipids, e.g. phosphatidic acid, phosphatidylserine and phosphatidylinositol, but not with phosphatidylcholine or phosphatidylethanolamine. The phosphatidylinositol and phosphatidylserine complexes are chloroform soluble, i.e. proteolipids. 8. The possibility that complexes between EAE protein and acidic phospholipids occur in vivo is discussed. Triphosphoinositide and EAE protein occur in ox brain myelin in approximately the same concentration ratios as they do in complex II, formed at physiological salt concentration and pH.  相似文献   

16.
Abstract: Experimental allergic encephalomyelitis (EAE) is an autoimmune, animal model of multiple sclerosis (MS) in which demyelination and paralysis are evident. Quinolinic acid (QUIN) is a neurotoxin and endogenous N -methyl- d -aspartate receptor agonist formed from tryptophan. The role of neurotoxins in general and QUIN in particular in EAE or MS is unknown. Lewis rats inoculated with myelin basic protein developed signs of EAE by day 12, were killed, and their tissues assayed for QUIN by gas chromatography with mass spectrometry. QUIN levels were significantly elevated in the more caudal regions of the spinal cords of animals with EAE. Brain, serum, and liver levels of QUIN were not altered. In a similar manner, QUIN in mylin basic protein-injected, asymptomatic animals was not different from control animals. The time course for QUIN was similar to the neurological signs of the disorder; however, the initial elevation in QUIN occurred before the appearance of behavioral signs. Last, treatment with the glucocorticoid dexamethasone prevented both the signs of EAE and the elevation in spinal cord QUIN. It is not known whether QUIN contributes to the paralysis in EAE. However, if QUIN is pathogenic in EAE, this finding could have therapeutic implications for MS.  相似文献   

17.
The immunosuppressive effects of cyclosporin A (CsA) were tested on actively induced and passively transferred experimental allergic encephalomyelitis (EAE). Actively induced EAE could be inhibited if CsA was administered per os at 25 mg/kg/day but not at 10 mg/kg/day. Passive transfer of clinical EAE occurred in all cell recipients including those fed CsA at either 25 or 50 mg/kg/day. Cyclosporin A could inhibit the development of transfer active cells in vitro and in vivo, however, inhibition of transfer active populations by CsA required the presence of CsA during the initial stage of cell response. If CsA was added to Con A-stimulated spleen cell cultures after a delay of 24 hr then these cells transferred clinical disease. Similarly, animals fed CsA concurrently with basic protein sensitization did not develop cell populations capable of transferring EAE. If CsA feeding commenced 2 or 4 days following sensitization all basic proteinsensitized animals still failed to develop EAE; however these latter groups of animals were a suitable source of cells capable of transferring some signs of clinical EAE.  相似文献   

18.
Lewis rats are susceptible to experimental autoimmune encephalomyelitis (EAE). Most rats recover from paralysis and are subsequently resistant to the disease. In an adoptive transfer system, we found that lymph node cells (LNC) from rats that had recovered from EAE protect syngeneic recipients from the disease when the latter are challenged with encephalitogenic myelin basic protein and adjuvant after receiving donor cells. Suppression is antigen-specific and requires viable LNC. In contrast to the suppressor cells we previously studied in tolerized rats, which were nonadherent T lymphocytes, the suppressor cells found in rats that have recovered from EAE adhere to glass wool. However, they are not retained on Sephadex G-10 columns to which macrophages adhere. Suppressor activity is enriched in the nylon wool-adherent LNC population (which consists of approximately 80% Ig+ cells). Our findings suggest that activation of adherent suppressor cells may be implicated in recovery from EAE. These may be adherent T cells, or B cells that produce anti-BP blocking antibodies.  相似文献   

19.
Experimental allergic encephalomyelitis (EAE) is an autoimmune syndrome that can be induced in Lewis rats by myelin basic protein (BP) in complete Freund's adjuvant (CFA). Rats that have recovered from a primary episode of EAE display paradoxical long-term resistance to EAE reinduction by BP-CFA. Previous observations indicated, however, that clinical disease could be reinduced in convalescent rats by a concomitant secondary challenge with BP-CFA + Bordetella pertussis extract (PERT). Vascular permeability changes in the central nervous system (CNS) paralleled disease reinduction. To further probe the relationship between disease reinduction and vascular permeability, convalescent rats were treated with the vasoactive amine antagonist cyproheptadine (CYP) prior to a secondary challenge with BP-CFA + PERT. Data presented here indicate that CYP treatment results in substantial protection of convalescent rats from clinical disease reinduction by BP-CFA + PERT. CYP did not, however, prevent the development of new CNS lesions. CYP therapy also altered the clinical course of EAE induced by a primary injection of BP-CFA + PERT. In these rats, there was a delay in the onset of clinical signs as well as in the appearance of CNS lesions. Nevertheless, both CYP-treated and untreated naive rats challenged with BP-CFA + PERT eventually developed severe and usually lethal EAE. The effect of CYP on EAE induced in naive rats without including PERT in the sensitization protocol was also evaluated. In contrast to the mitigating effect of CYP on EAE induced or reinduced by BP-CFA + PERT, CYP treatment did not affect the clinical course or the development of CNS lesions in rats challenged with BP-CFA alone. Likewise, the passive transfer of EAE, mediated by mitogen-stimulated cells obtained from BP-CFA-sensitized donors, was not affected by CYP treatment. Collectively, these data indicate that CYP therapy altered the expression of EAE induced by regimens that included PERT, but did not affect EAE induced without PERT. In view of the opposing effects of PERT and CYP on vascular permeability, these data are consistent with the hypothesis that alterations in vascular permeability may play a crucial role in controlling the expression of autoimmune neurological diseases.  相似文献   

20.
Immunization of common marmosets (Callithrix jacchus) with a single dose of human myelin in CFA, without administration of Bordetella pertussis, induces a form of autoimmune encephalomyelitis (EAE) resembling in its clinical and pathological expression multiple sclerosis in humans. The EAE incidence in our outbred marmoset colony is 100%. This study was undertaken to assess the genetic and immunological basis of the high EAE susceptibility. To this end, we determined the separate contributions of immune reactions to myelin/oligodendrocyte glycoprotein (MOG) and myelin basic protein to the EAE induction. Essentially all pathological features of myelin-induced EAE were also found in animals immunized with MOG in CFA, whereas in animals immunized with myelin basic protein in CFA clinical and pathological signs of EAE were lacking. The epitope recognition by anti-MOG Abs and T cells were assessed. Evidence is provided that the initiation of EAE is based on T and B cell activation by the encephalitogenic phMOG14-36 peptide in the context of monomorphic Caja-DRB*W1201 molecules.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号