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International Immunology Advance Access originally published online on February 15, 2006
International Immunology 2006 18(4):537-544; doi:10.1093/intimm/dxh394
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© The Japanese Society for Immunology. 2006. All rights reserved. For permissions, please e-mail: journals.permissions@oxfordjournals.org

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

Youngheun Jee1,2, Ruolan Liu1, Xue-Feng Bai3, Denise I. Campagnolo1, Fu-Dong Shi1 and Timothy L. Vollmer1

1 Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ 85013, USA
2 Department of Veterinary Medicine, Applied Radiological Science Institute, Cheju National University, Jeju, 690-756 South Korea
3 Department of Pathology, Ohio State University Medical Center, Columbus, OH 43210, USA

Correspondence to: T. L. Vollmer; E-mail: tvollmer{at}chw.edu


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

Keywords: EAE/MS, glatiramer acetate, Th2 cells


   Introduction
Top
 Abstract
 Introduction
Methods
 Results
 Discussion
 References
 
Glatiramer acetate (GA) (Copaxone®, formerly known as Copolymer-1) is a synthetic copolymer that consists of four amino acids: L-lysine, L-glutamic acid and L-tyrosine in a fixed molar ratio. The molecule was initially developed based on the structure of myelin basic protein (MBP) for the purpose of inducing experimental autoimmune encephalomyelitis (EAE) but was found to inhibit EAE in a variety of species (1, 2). GA not only suppressed the onset of acute EAE but also had a significant therapeutic effect in overcoming chronic relapsing EAE. Additionally, the suppressive effect of GA in EAE was not restricted to particular species, disease type or encephalitogen (3). Subsequently, GA was developed for treating patients with multiple sclerosis (MS) (4, 5). In controlled clinical trials, this drug significantly reduced relapse rates and progression of disability in MS with long-term efficacy, remarkable safety and tolerability (6, 7). The mechanism of GA function is not fully elucidated. The current hypothesis is that GA-reactive T cells may exert their protective action by entering the central nervous system (CNS) and producing anti-inflammatory cytokines in response to cross-recognition of MBP or other myelin components that inhibit Th1 autoaggressive T cells via bystander suppression (8–11).

The specific cytokines produced by polarized Th1 and Th2 cells are the primary effectors that promote the differentiation of precursor Th cells, but these cytokines also cross-regulate the other subset's functional activity. IL-4 and IL-10 are two prominent Th2 cytokines that have been demonstrated to exert anti-inflammatory effects in various pathological conditions and to promote Th2 cell differentiation. To ask whether Th2 cells mediate the effects of GA, we determined the therapeutic effects of GA in myelin oligodendrocyte glycoprotein (MOG) 35–55-primed Th2 cytokine-deficient mice, i.e. IL-4-, IL-10-deficient and IL-4/IL-10 double-deficient mice. This study demonstrates that GA can suppress MOG-induced EAE in not only wild-type mice but also IL-4-, IL-10- and IL-4/IL-10-deficient mice, leading to diminished myelin-reactive T cell expansion and reduced production of myelin antigen-induced pro-inflammatory cytokines. Our results caution against the notion that Th2 cells and bystander suppression account for the effect of GA on EAE and suggest that an alternative mechanism may operate in GA-treated MS patients.


   Methods
Top
 Abstract
 Introduction
 Methods
Results
 Discussion
 References
 
Mice
C57BL/6 (B6, wild type) mice and IL-4-, IL-10-deficient mice on the B6 background were purchased from Jackson Laboratory (Bar Harbor, ME, USA). The cytokine-deficient mice used in this study were previously described (12, 13). We cross-bred IL-4- and IL-10-deficient mice to generate IL-4/IL-10 double-mutant mice. Mice were housed in animal facilities of the Barrow Neurological Institute, Phoenix, AZ, USA, and The Scripps Rodent Colony, La Jolla, CA, USA. Female mice, 8–10 weeks of age at the initiation of the experiments, were used.

Induction of EAE
EAE was induced by subcutaneous (s.c.) flank and tail base injections of 200 µg of MOG peptide in CFA (Difco, Detroit, MI, USA) containing 500 µg of heat-inactivated Mycobacterium tuberculosis on day 0, supplemented by intravenous injections of 200 ng of pertussis toxin on day 2 (List Biologic, Campbell, CA, USA). The murine MOG35–55 peptide (M-E-V-G-W-Y-R-S-P-F-S-R-V-V-H-L-Y-R-N-G-K) (14) was synthesized (Bio Synthesis Inc., Lewisville, TX, USA). The mice were observed daily for clinical signs of disease and scored on an arbitrary scale of 0–5 with gradations of 0.5 for intermediate scores (15): 0, no clinical signs; 1, flaccid tail; 2, hind limb weakness or abnormal gait; 3, complete hind limb paralysis; 4, complete hind limb paralysis with forelimb weakness or paralysis and 5, moribund or deceased.

GA treatment
GA (Copaxone®; Teva Pharmaceutical Industries, Ltd, Petah Tiquava, Israel) (0.1 mg) was injected s.c. on day 7 before immunization with MOG in 100 µl of incomplete Freund adjuvant. Controls were matched mice without injected GA.

Culture medium
Cells from these mice were suspended in Dulbecco's modification of Eagle's medium (Gibco, Paisley, UK) supplemented with 1% (v/v) minimum essential medium (Gibco), 2 mM glutamine (Flow Laboratories, Irvine, CA, USA), 50 IU ml–1 penicillin, 50 mg ml–1 streptomycin and 10% (v/v) FCS (both from Gibco).

T cell proliferation
Mononuclear cells (MNC) were obtained by mincing spleens through a wire mesh. MNC (4 x 105) were cultured in each well of 96-well, round-bottom microtiter plates (Nunc, Copenhagen, Denmark) in the presence or absence of MOG35–55 peptide (10 µg ml–1), GA (10 µg ml–1), whole MBP (10 µg ml–1) or Con A (2.5 µg ml–1) (Sigma Chemical Co., St. Louis, MO, USA). After 4 days of incubation, the cells were pulsed for 18 h with 10 µl aliquots containing 1 µCi of 3H-methylthymidine (specific activity 42 Ci mmol–1; Amersham, Arlington Heights, IL, USA). Cells were harvested onto glass fiber filters, and thymidine incorporation was measured.

Cytokine assay
Single-cell suspensions of MOG-primed spleen cells were cultured in the presence or absence of MOG35–55 (10 µg ml–1), GA (10 µg ml–1), MBP (10 µg ml–1) or Con A (5 µg ml–1). The supernatants were collected after 48 h in culture. IFN-{gamma}, tumor necrosis factor-{alpha} (TNF-{alpha}), IL-10, IL-4 and IL-5 production in culture supernatants was measured by using optEIA kits (PharMingen, San Diego, CA, USA) and following the manufacturer's instructions. Cytokine levels were calculated with standard curves using recombinant murine cytokines.

Statistical analysis
Mean of maximum score was evaluated by Student's t-test. The difference of proliferative T cell response and amounts of cytokines between groups were analyzed for significance by Fisher's exact test and Mann-Whitney's U-test, respectively.


   Results
Top
 Abstract
 Introduction
 Methods
 Results
Discussion
 References
 
GA suppresses EAE in IL-4-, IL-10- and IL-4/IL-10-deficient mice
We first confirmed the clinically beneficial effects of GA in mice with MOG-induced EAE. For this purpose, we pre-treated B6 mice with GA and subsequently immunized these mice s.c. with MOG. As shown in Fig. 1(A) and Table 1, the immunization with MOG peptide together with CFA and pertussis toxin induced moderate to severe EAE (mean maximal clinical score 2.5 ± 0.34) in the majority of animals (87%, 7/8). The disease onset is on average 16 days after immunization in GA-untreated B6 mice. In contrast, GA-treated mice had much milder EAE with a mean maximal clinical score of 1.22 ± 0.31 and a delayed mean time of disease onset (22 ± 3.2 days after immunization). The disease severity and incidence of GA-treated mice were significantly lower than that of untreated control mice (1.22 ± 0.31, 33.3%, 3/9).


Figure 1
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  		Fig. 1. Therapeutic effects of GA on MOG35–55 peptide-induced EAE were independent of IL-4 and/or IL-10 cytokines. Wild-type (A), IL-4-deficient (B), IL-10-deficient (C) and IL-4/IL-10-deficient (D) mice were treated with GA (0.1 mg per mouse injected s.c.) 7 days before immunization with MOG35–55 peptide in CFA (Methods) and then monitored for development of EAE. *P < 0.05 versus PBS-treated mice of corresponding strain.

 

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  		Table 1. Effects of GA on EAE development in IL-4-, IL-10-deficient and IL-4/IL-10 double-deficient mice

 
To determine whether these beneficial effects of GA were mediated by Th2 cells, we induced EAE in B6 mice and Th2-type cytokine-deficient mice, i.e. IL-4-, IL-10- and IL-4/IL-10-deficient mice. Previous results regarding EAE phenotype in IL-4- and IL-10-deficient mice are conflicting (16). In our hands, the clinical signs of EAE were significantly different in the untreated wild-type mice and the IL-4/IL-10-deficient mice. Interestingly, compared with untreated control IL-4-, IL-10- and IL-4/IL-10-deficient mice, Th2 cytokine-deficient mice treated with GA had significant reductions in the incidence and severity of disease (Fig. 1B–D and Table 1). In these Th2 cytokine-deficient mice, GA treatment also delayed disease onset, the median days of which were 21.4, 23 and 21.2 compared with 16 days in the untreated groups. The clinical signs of EAE were not significantly different between the wild-type and IL-4-, IL-10- and IL-4/IL-10-deficient mice treated with GA. These results indicate that GA induces protective effects against EAE independent of IL-4 and/or IL-10.

Effects of GA on the T cell proliferative response in IL-4-, IL-10- and IL-4/IL-10-deficient mice
We next questioned whether the absence of IL-4 and/or IL-10 affected the induction and expansion of MOG35–55-specific T cell responses in GA-treated mice. We first tested antigen-specific spleen cell proliferation in MOG35–55-sensitized wild-type and Th2 cytokine-deficient mice with or without GA treatment. As shown in Fig. 2, splenocytes from wild-type and Th2 cytokine-deficient mice mounted significant proliferative responses to MOG35–55 and GA. Compared with control B6 mice not treated with GA, proliferation of antigen-specific T cells in response to the MOG35–55 peptide was significantly decreased in GA-treated B6 mice (Fig. 2A). Additionally, all cytokine-deficient mice treated with GA showed significantly reduced proliferation in response to the MOG35–55 peptide (Fig. 2B–D). Thus, after GA treatment, the extents of proliferation in response to the MOG35–55 peptide were similar in splenocytes derived from IL-4-, IL-10- and IL-4/IL-10-deficient mice to those from wild-type mice. On the other hand, there was no significant difference in the proliferative responses to GA between untreated mice and GA-treated mice regardless of strain. Collectively, GA therapy in IL-4- and IL-10-deficient mice reduced myelin-reactive T cell expansion and altered antigen-specific T cell proliferation even in IL-4-, IL-10- and IL-4/IL-10-deficient mice. These data demonstrate that in the absence of IL-4- and/or IL-10-secreting T cells, GA-induced T cells can regulate myelin-specific cells and inhibit their autoreactivity.


Figure 2
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  		Fig. 2. Effects of GA on MOG35–55-reactive T cell responses. Groups of mice were treated with GA prior to immunization with MOG35–55 peptide in CFA (Methods). Wild-type (A), IL-4-deficient (B), IL-10-deficient (C) and IL-4/IL-10-deficient (D) mice. Mice were killed at day 25 after immunization, and MNC were isolated from their spleen. Proliferative responses to the antigens (MOG35–55 peptide, GA, whole MBP or Con A) shown were assessed in duplicate wells per experiment. Background proliferation was 758 ± 82 counts per minute (c.p.m.) and Con A-induced proliferation was 12 002 ± 823 c.p.m. Data are means and SD of c.p.m. and are representative of three experiments. Statistical evaluation was performed to compare the untreated control and GA-treated groups. *P < 0.05.

 
Effects of GA on the cytokine response in IL-4-, IL-10- and IL-4/IL-10-deficient mice
We then determined cytokine responses in IL-4-, IL-10- and IL-4/10-deficient mice after GA treatment. Splenocytes from mice immunized with MOG35–55 were stimulated in vitro with the antigens listed in Fig. 3, then measured for cytokines by ELISA. Supernatants from these splenocytes produced very low levels of cytokines without specific antigen stimulation (data not shown). As Fig. 3(A and B) depicts, IFN-{gamma} and TNF-{alpha} production of encephalitogenic T cells in response to the MOG35–55 peptide was significantly decreased in GA-treated B6 mice compared with their untreated counterparts. In contrast, the levels of IL-4, IL-10 (Fig. 4A) and IL-5 (Fig. 4B) production increased slightly in GA treated compared with untreated B6 mice, but there was no significant difference among these mice. On the other hand, GA-specific T cells responded to the GA by secreting smaller amounts of Th1 (IFN-{gamma} and TNF-{alpha}) and Th2 (IL-4, IL-5 and IL-10) cytokines compared with those of MOG-specific T cells. There was no significant change of cytokine secretion in GA-specific T cells in vitro in the presence of GA, regardless of GA treatment to B6 mice. These results suggest that the response of MOG- and GA-specific T cells were not Th2 biased and that GA did not induce Th2-polarized T cells in GA-treated wild-type mice.


Figure 3
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  		Fig. 3. Effects of GA on Th1 cytokine production (IFN-{gamma} and TNF-{alpha}). Twenty-five days after immunization with MOG35–55 peptide and GA treatment (Methods), spleen cells were isolated and cultured for 2 days in the presence of multiple stimuli. Individual culture supernatants in response to stimuli were collected for the cytokine assay. MOG35–55 peptide-specific cytokine production by T cells from MOG35–55/CFA-immunized mice was measured by ELISA. (A) IFN-{gamma} (B) TNF-{alpha}. Spontaneous cytokine release: IFN-{gamma}, 66 ± 21 pg ml–1; TNF-{alpha}, 38± 21 pg ml–1. No difference was revealed in spontaneous cytokine release between untreated controls and GA-treated mice. All results are expressed as mean values ± SD. These data represent one out of two independent experiments with similar results (n = 4). Statistical evaluation was performed to compare the untreated control and GA-treated groups. *P < 0.05.

 

Figure 4
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  		Fig. 4. Effects of GA on Th2 cytokine production (IL-4, IL-10 and IL-5). This experimental protocol paralleled that for the pro-inflammatory cytokine assay. (A) IL-4 and IL-10 and (B) IL-5. Spontaneous cytokine release; IL-4, undetectable; IL-5, 32 ± 11 pg ml–1; IL-10, undetectable.

 
Next, we examined the cytokine response in Th2 cytokine-deficient mice. In encephalitogenic T cells of IL-4-, IL-10- and IL-4/IL-10-deficient mice, levels of IFN-{gamma} and TNF-{alpha} production of MOG35–55-specific T cells after GA treatment were reduced compared with those of untreated mice (Fig. 3A and B). T cells derived from untreated mice produced large amounts of IFN-{gamma} and TNF-{alpha}, whereas lower amounts of these cytokines were secreted by T cells from GA-treated mice. In contrast, Th2 cytokine levels, i.e. of IL-5 (Fig. 4B) as well as IL-4, IL-10 (Fig. 4A), in MOG- and GA-specific T cells were similar in GA-treated or untreated cytokine-deficient EAE mice, indicating that no Th2 polarization occurred. Similar to B6 mice, Th1 and Th2 cytokine secretion by GA-specific T cells in vitro in the presence of GA did not differ significantly in GA-treated and -untreated mice. Clearly, MOG- and GA-specific T cells in these mice were not Th2 polarized and the Th1 cytokine production of myelin-reactive T cells in GA-treated mice significantly decreased. These data suggest that the therapeutic effect of GA in IL-4-, IL-10- and IL-4/IL-10-deficient mice was associated with reduced production of antigen-induced IFN-{gamma} and TNF-{alpha}.


   Discussion
Top
 Abstract
 Introduction
 Methods
 Results
 Discussion
References
 
This study tested the hypothesis that the therapeutic effect of GA stems from immune deviation toward Th2-polarized GA-specific T cells by using IL-4-, IL-10- and IL-4/IL-10-deficient mice. Our results indicated that GA maintains its therapeutic effect on EAE independent of the Th2 cytokines IL-4 and IL-10, either alone or combined, that is, without immune deviation toward Th2-polarized T cells. Further, the action of GA in IL-4-, IL-10- and IL-4/IL-10-deficient mice was associated with reduced production of antigen-induced IFN-{gamma} and TNF-{alpha}. Thus, during GA therapy, the Th1 cytokine production of myelin-reactive T cells in Th2-type cytokine-deficient mice was significantly decreased just as it was in wild-type mice.

The exact mechanism by which GA exerts its observed beneficial effect in EAE and MS is not fully understood. One of the proposed mechanisms of GA's action is that it inhibits the presentation of several myelin antigens to T cells (1, 2, 17). Since the amino acid composition of MBP, to a certain extent, overlaps that of GA, it was postulated that cross-reactive immune mechanisms might be involved in the therapeutic effects of GA in EAE and MS (1, 15). However, the notion of cross-reactivity has been challenged by a number of subsequent studies demonstrating that GA and MBP are inhibitory rather than cross-reactive (8, 14). Additionally, specific TCR antagonism against the immunodominant epitope MBP82–100 and blocking of the MHC have been reported (18). This cross-reactive and/or inhibitory hypothesis to account for the suppressive effect of GA in EAE came into question because of the observation that GA inhibits not only MBP-specific T cell lines but also ovalumin-specific T cell lines (19). Furthermore, GA inhibits binding of proteolipid protein and MOG and suppresses EAE induced by these antigens (20). Since these molecules do not share amino acid sequence homology with GA, the inhibition of EAE by GA through its competitive or cross-reactive features is doubtful.

More recently, evidence has emerged that the GA-reactive T cells may exert their protective action by entering the CNS and producing anti-inflammatory cytokines in response to cross-recognition of MBP or other myelin components (bystander suppression) (8–11). These GA-specific T cells migrate through the blood/brain barrier to the CNS, where upon activation by myelin antigens, they produce anti-inflammatory cytokines. Since it is technically difficult to demonstrate GA-reactive T cells in the human CNS, tracking studies in animals with EAE have been done to support this mechanism. Whether GA acts systemically, centrally or both in humans is unclear. The action of GA to induce anergy in myelin-reactive T cells (21) and to inhibit the appearance of new gadolinium-enhancing lesions on brain magnetic resonance imaging may suggest a systemic effect (22).

Induction of Th2 deviation by GA has not been demonstrated in all model systems tested thus far. In addition, Th2 deviation in response to therapeutic intervention is sometimes an outcome rather than the cause of protection from disease (23). Therefore, additional mechanisms underlying the therapeutic effects of GA in EAE or MS must be involved. Indeed, some reports suggest that GA-reactive T cells elaborate the brain-derived neurotrophic factor (BDNF), a potent substance that has a neuroprotective effect and induces repair in the CNS. Indeed, BDNF has been demonstrated at the site of inflammation in MS and in close proximity to its receptor Trk-b (24).

Alteration or reduction of CD4+CD25+ regulatory T cell function has been reported in patients with MS and other autoimmune diseases (25–27). Restoration of these regulatory cell functions may re-establish tolerance to self-antigens in these patients. Interestingly, two independent studies provide evidence that GA can restore regulatory T cell functions in MS patients (28, 29). Others also provided evidence indicating the role of GA in the induction of CD4+CD25+ regulatory T cells through the activation of Foxp3 (28, 30, 31).

It is clear from the present study that, despite the absence of two prominent Th2 cytokines, IL-4 and IL-10, GA still provides beneficial effects in EAE equal to the wild-type control animals. Although we cannot exclude the possibility that different results may be obtained with strains of mice with different MHC alleles or with other EAE models such as the rat model, it seems unlikely that all models of EAE are similarly responsive to GA (1, 2). Also, in our study, GA was administered before induction of EAE in a prevention paradigm. It is possible that the mechanism of action of GA in a treatment paradigm in established disease is different. Studies to address this possibility are being pursued.

Therefore, our results suggest that the concept of induction of Th2 cells and bystander suppression as an explanation of GA effects in EAE or MS may be incomplete and that an alternative mechanism may operate in GA-treated MS patients. Since GA may be inducing regulatory T cells which may have neuroprotective properties, the possible involvement of regulatory CD4+CD25+ T cells, neurotrophic factors and/or other factors offer opportunities for future exploration that may lead to strategies for enhancing the clinical effect of GA and related therapies.


   Acknowledgements
 
We thank Susan Rhodes and Mary Price for technical support and Phyllis Minick for editorial assistance. This work was supported by Barrow Neurological Foundation (T.L.V. and F.-D.S.), Muscular Dystrophy Association (R.L.L. and F.-D.S.), National Institutes of Health (D.I.C. and X.-F.B.), Korea Research Foundation of the Korean Government (MOEHRD) (no. R04-2004-000-10226-0) and program of Basic Energy Research Institute (BAERI) funded by the Ministry of Science & Technology of Korea.


   Abbreviations
 
B6   C57BL/6
BDNF   brain-derived neurotrophic factor
CNS   central nervous system
EAE   experimental autoimmune encephalomyelitis
GA   glatiramer acetate
MBP   myelin basic protein
MNC   mononuclear cells
MOG   myelin oligodendrocyte glycoprotein
MS   multiple sclerosis
PT   pertussis toxin
s.c.   subcutaneous
TNF-{alpha}   tumor necrosis factor-{alpha}

   Notes
 
Transmitting editor: L. Steinman

Received 12 August 2005, accepted 5 January 2006.


   References
Top
 Abstract
 Introduction
 Methods
 Results
 Discussion
 References
 

  1. Teitelbaum, D., Aharoni, R., Arnon, R. and Sela, M. 1988. Specific inhibition of the T-cell response to myelin basic protein by the synthetic copolymer Cop 1. Proc. Natl Acad. Sci. USA 85:9724.[Abstract/Free Full Text]
  2. Teitelbaum, D., Fridkis-Hareli, M., Arnon, R. and Sela, M. 1996. Copolymer 1 inhibits chronic relapsing experimental allergic encephalomyelitis induced by proteolipid protein (PLP) peptides in mice and interferes with PLP-specific T cell responses. J. Neuroimmunol. 64:209.[CrossRef][ISI][Medline]
  3. Arnon, R. 1996. The development of Cop 1 (Copaxone), an innovative drug for the treatment of multiple sclerosis: personal reflections. Immunol. Lett. 50:1.[CrossRef][ISI][Medline]
  4. Comi, G. and Moiola, L. 1997. Copolymer-1. Baillieres Clin. Neurol. 6:495.[Medline]
  5. Johnson, K. P. 1994. Experimental therapy of relapsing-remitting multiple sclerosis with copolymer-1. Ann. Neurol. 36 (Suppl.):S115.
  6. Bornstein, M. B., Miller, A. I., Slagle, S., Arnon, R., Sela, M. and Teitelbaum, D. 1984. Clinical trials of copolymer I in multiple sclerosis. Ann. NY Acad. Sci. 436:366.[CrossRef][ISI][Medline]
  7. Johnson, K. P., Brooks, B. R., Cohen, J. A. et al. 1995. Copolymer 1 reduces relapse rate and improves disability in relapsing-remitting multiple sclerosis: results of a phase III multicenter, double-blind placebo-controlled trial. The copolymer 1 multiple sclerosis study group. Neurology 45:1268.[Abstract]
  8. Lisak, R. P., Zweiman, B., Blanchard, N. and Rorke, L. B. 1983. Effect of treatment with Copolymer 1 (Cop-1) on the in vivo and in vitro manifestations of experimental allergic encephalomyelitis (EAE). J. Neurol. Sci. 62:281.[CrossRef][ISI][Medline]
  9. Aharoni, R., Teitelbaum, D., Sela, M. and Arnon, R. 1997. Copolymer 1 induces T cells of the T helper type 2 that crossreact with myelin basic protein and suppress experimental autoimmune encephalomyelitis. Proc. Natl Acad. Sci. USA 94:10821.[Abstract/Free Full Text]
  10. Aharoni, R., Teitelbaum, D., Sela, M. and Arnon, R. 1998. Bystander suppression of experimental autoimmune encephalomyelitis by T cell lines and clones of the Th2 type induced by copolymer 1. J. Neuroimmunol. 91:135.[CrossRef][ISI][Medline]
  11. Chen, M., Gran, B., Costello, K., Johnson, K., Martin, R. and Dhib-Jalbut, S. 2001. Glatiramer acetate induces a Th2-biased response and crossreactivity with myelin basic protein in patients with MS. Mult. Scler. 7:209.0
  12. Bettelli, E., Das, M. P., Howard, E. D., Weiner, H. L., Sobel, R. A. and Kuchroo, V. K. 1998. IL-10 is critical in the regulation of autoimmune encephalomyelitis as demonstrated by studies of IL-10- and IL-4-deficient and transgenic mice. J. Immunol. 161:3299.[Abstract/Free Full Text]
  13. Falcone, M., Rajan, A. J., Bloom, B. R. and Brosnan, C. F. 1998. A critical role for IL-4 in regulating disease severity in experimental allergic encephalomyelitis as demonstrated in IL-4-deficient C57BL/6 mice and BALB/c mice. J. Immunol. 160:4822.[Abstract/Free Full Text]
  14. Burns, J. and Littlefield, K. 1991. Failure of copolymer I to inhibit the human T-cell response to myelin basic protein. Neurology 41:1317.[Abstract/Free Full Text]
  15. Teitelbaum, D., Aharoni, R., Sela, M. and Arnon, R. 1991. Cross-reactions and specificities of monoclonal antibodies against myelin basic protein and against the synthetic copolymer 1. Proc. Natl Acad. Sci. USA 88:9528.[Abstract/Free Full Text]
  16. Singh, A. K., Wilson, M. T., Hong, S. et al. 2001. Natural killer T cell activation protects mice against experimental autoimmune encephalomyelitis. J. Exp. Med. 194:1801.[Abstract/Free Full Text]
  17. Ben-Nun, A., Mendel, I., Bakimer, R. et al. 1996. The autoimmune reactivity to myelin oligodendrocyte glycoprotein (MOG) in multiple sclerosis is potentially pathogenic: effect of copolymer 1 on MOG-induced disease. J. Neurol. 243:S14.[CrossRef][ISI][Medline]
  18. Aharoni, R., Teitelbaum, D., Arnon, R. and Sela, M. 1999. Copolymer 1 acts against the immunodominant epitope 82–100 of myelin basic protein by T cell receptor antagonism in addition to major histocompatibility complex blocking. Proc. Natl Acad. Sci. USA 96:634.[Abstract/Free Full Text]
  19. Racke, M. K., Martin, R., McFarland, H. and Fritz, R. B. 1992. Copolymer-1-induced inhibition of antigen-specific T cell activation: interference with antigen presentation. J. Neuroimmunol. 37:75.[CrossRef][ISI][Medline]
  20. Fridkis-Hareli, M., Teitelbaum, D., Gurevich, E. et al. 1994. Direct binding of myelin basic protein and synthetic copolymer 1 to class II major histocompatibility complex molecules on living antigen-presenting cells—specificity and promiscuity. Proc. Natl Acad. Sci. USA 91:4872.[Abstract/Free Full Text]
  21. Gran, B., Tranquill, L. R., Chen, M. et al. 2000. Mechanisms of immunomodulation by glatiramer acetate. Neurology 55:1704.[Abstract/Free Full Text]
  22. Comi, G., Filippi, M. and Wolinsky, J. S. 2001. European/Canadian multicenter, double-blind, randomized, placebo-controlled study of the effects of glatiramer acetate on magnetic resonance imaging—measured disease activity and burden in patients with relapsing multiple sclerosis. European/Canadian glatiramer acetate study group. Ann. Neurol. 49:290.[CrossRef][ISI][Medline]
  23. Van Kaer, L. 2005. alpha-galactosylceramide therapy for autoimmune diseases: prospects and obstacles. Nat. Rev. Immunol. 5:31.[CrossRef][ISI][Medline]
  24. Stadelmann, C., Kerschensteiner, M., Misgeld, T., Bruck, W., Hohlfeld, R. and Lassmann, H. 2002. BDNF and gp145trkB in multiple sclerosis brain lesions: neuroprotective interactions between immune and neuronal cells? Brain 125:75.[Abstract/Free Full Text]
  25. Putheti, P., Pettersson, A., Soderstrom, M., Link, H. and Huang, Y. M. 2004. Circulating CD4+CD25+ T regulatory cells are not altered in multiple sclerosis and unaffected by disease-modulating drugs. J. Clin. Immunol. 24:155.[CrossRef][ISI][Medline]
  26. Putheti, P., Soderstrom, M., Link, H. and Huang, Y. M. 2003. Effect of glatiramer acetate (Copaxone) on CD4+CD25high T regulatory cells and their IL-10 production in multiple sclerosis. J. Neuroimmunol. 144:125.[CrossRef][ISI][Medline]
  27. Viglietta, V., Baecher-Allan, C., Weiner, H. L. and Hafler, D. A. 2004. Loss of functional suppression by CD4+CD25+ regulatory T cells in patients with multiple sclerosis. J. Exp. Med. 199:971.[Abstract/Free Full Text]
  28. Hong, J., Li, N., Zhang, X., Zheng, B. and Zhang, J. Z. 2005. Induction of CD4+CD25+ regulatory T cells by copolymer-I through activation of transcription factor Foxp3. Proc. Natl Acad. Sci. USA 102:6449.[Abstract/Free Full Text]
  29. Viglietta, V., Baaecher-Allan, C., Khoury, S. and Hafler, D. A. 2005. Defects in regulatory CD4+CD25+ T cells in patients with MS; effects of glatiramer acetate. Neurology 64(Suppl. 1):S32.001.
  30. Hori, S., Nomura, T. and Sakaguchi, S. 2003. Control of regulatory T cell development by the transcription factor Foxp3. Science 299:1057.[Abstract/Free Full Text]
  31. Yagi, H., Nomura, T. Nakamura, K. et al. 2004. Crucial role of FOXP3 in the development and function of human CD25+CD4+ regulatory T cells. Int. Immunol. 16:1643.[Abstract/Free Full Text]

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