Cross-reactions and specificities of monoclonal antibodies against myelin basic protein and against the synthetic copolymer 1

Assessing the In Vitro Potential of Glatiramer Acetate (Copaxone®) as a Chemotherapeutic Candidate for the Treatment of Cryptococcus neoformans Infection

Cryptococcosis is a systemic mycosis affecting immunosuppressed individuals, caused by various Cryptococcus species. The current treatment utilizes a combination of antifungal drugs, but issues such as nephrotoxicity, restricted or limited availability in certain countries, and resistance limit their effectiveness. Repurposing approved drugs presents a viable strategy for developing new antifungal options. This study investigates the potential of glatiramer acetate (Copaxone®) as a chemotherapy candidate for Cryptococcus neoformans infection. Various techniques are employed to evaluate the effects of glatiramer acetate on the fungus, including microdilution, XTT analysis, electron and light microscopy, and physicochemical measurements. The results demonstrate that glatiramer acetate exhibits antifungal properties, with an IC50 of 0.470 mg/mL and a minimum inhibitory concentration (MIC) of 2.5 mg/mL. Furthermore, it promotes enhanced cell aggregation, facilitates biofilm formation, and increases the secretion of fungal polysaccharides. These findings indicate that glatiramer acetate not only shows an antifungal effect but also modulates the key virulence factor-the polysaccharide capsule. In summary, repurposing glatiramer acetate as a potential chemotherapy option offers new prospects for combating C. neoformans infection. It addresses the limitations associated with current antifungal therapies by providing an alternative treatment approach.

B-Cell Activity Predicts Response to Glatiramer Acetate and Interferon in Relapsing-Remitting Multiple Sclerosis

Objective

We investigated the predictive value of the enzyme-linked immunospot technique (ELISPOT) in identifying patients with relapsing-remitting multiple sclerosis (RRMS) who will respond to treatment with glatiramer acetate (GA) or interferon-β (IFN-β), based on the brain-reactive B-cell activity of peripheral blood cells.

Methods

In this retrospective, cross-sectional, real-world multicenter study, we identified patients with RRMS in the NeuroTransData MS registry and stratified them based on their documented treatment response (relapse-free in the first 12 months of treatment) to GA or IFN-β. The GA group comprised 73 patients who responded to GA and 35 nonresponders. The IFN-β group comprised 62 responders to IFN-β and 37 nonresponders. Patients with previous or current therapy affecting B-cell activity were excluded. We polyclonally stimulated mononuclear cells from peripheral blood samples (collected after participant selection) and investigated brain-reactive B-cell activity after incubation on brain tissue lysate-coated ELISPOT plates. Validity metrics of the ELISPOT testing results were calculated (Python 3.6.8) in relation to the clinical responsiveness in the 2 treatment groups.

Results

The ELISPOT B-cell activity assay showed a sensitivity of 0.74, a specificity of 0.76, a positive predictive value of 0.78, a negative predictive value of 0.28, and a diagnostic OR of 8.99 in predicting clinical response to GA vs IFN-β therapy in patients with RRMS.

Conclusion

Measurement of brain-reactive B-cell activity by ELISPOT provides clinically meaningful predictive probabilities of individual patients' treatment response to GA or IFN-β. The assay has the potential to improve the selection of optimal first-line treatment for individual patients with RRMS.

Classification of Evidence

This study provides Class II evidence that in patients with RRMS, the brain reactivity of their peripheral-blood B cells predicts clinical response to GA and IFN-β.

Advanced DNA-Based Point-of-Care Diagnostic Methods for Plant Diseases Detection

Diagnostic technologies for the detection of plant pathogens with point-of-care capability and high multiplexing ability are an essential tool in the fight to reduce the large agricultural production losses caused by plant diseases. The main desirable characteristics for such diagnostic assays are high specificity, sensitivity, reproducibility, quickness, cost efficiency and high-throughput multiplex detection capability. This article describes and discusses various DNA-based point-of care diagnostic methods for applications in plant disease detection. Polymerase chain reaction (PCR) is the most common DNA amplification technology used for detecting various plant and animal pathogens. However, subsequent to PCR based assays, several types of nucleic acid amplification technologies have been developed to achieve higher sensitivity, rapid detection as well as suitable for field applications such as loop-mediated isothermal amplification, helicase-dependent amplification, rolling circle amplification, recombinase polymerase amplification, and molecular inversion probe. The principle behind these technologies has been thoroughly discussed in several review papers; herein we emphasize the application of these technologies to detect plant pathogens by outlining the advantages and disadvantages of each technology in detail.

Clinical significance of glatiramer acetate antibodies

Glatiramer acetate is a mixture of synthetic peptides that are cross-reactive with MBP. The antigen-based therapy induces a shift to an anti-inflammatory Th2 bias and is used in the treatment of relapsing-remitting multiple sclerosis. Like other peptide antigens, GA induces an antibody response in all patients. In contrast to biologically active agents, such as the recombinant interferon beta drugs, GA is a peptide antigen that lacks intrinsic biological activity. In vitro and in vivo data have shown that GA-reactive antibodies are not neutralizing. Antibodies do not alter the principal immunological effects of GA, including binding to MHC Class II molecules, activation and proliferation of GA-reactive T cells, and the release of anti-inflammatory Th2 cytokines. Higher antibody titres do not appear to be associated with a deterioration in clinical endpoints, such as relapse rate, EDSS progression or the occurrence of side effects in MS patients treated with GA. The presence of GA-reactive antibodies may promote remyelination and enhance the immunological and clinical effects of GA, indicating that they may be part of GA's mechanism of action. Multiple Sclerosis 2007; 13: S28—S35. http://msj.sagepub.com

Overview on poly(ADP-ribose) immuno-biomedicine and future prospects

Poly(ADP-ribose), identified in 1966 independently by three groups Strassbourg, Kyoto and Tokyo, is synthesized by poly(ADP-ribose) polymerases (PARP) from NAD(+) as a substrate in the presence of Mg(2+). The structure was unique in that it has ribose-ribose linkage. In the early-1970s, however, its function in vivo/in vitro was still controversial and the antibody against it was desired to help clear its significance. Thereupon, the author tried to produce antibody against poly(ADP-ribose) in rabbits and succeeded in it for the first time in the world. Eventually, this success has led to the following two groundbreaking papers in Nature: "Naturally-occurring antibody against poly(ADP-ribose) in patients with autoimmune disease SLE", and "Induction of anti-poly(ADP-ribose) antibody by immunization with synthetic double-stranded RNA, poly(A)·poly(U)".On the way to the publication of the first paper, a reviewer gave me a friendly comment that there is "heteroclitic" fashion as a mechanism of the production of natural antibody. This comment was really a God-send for me, and became a train of power for publication of another paper, as described above. Accordingly, I thought this, I would say, episode is worth describing herein. Because of its importance in biomedical phenomena, a certain number of articles related to "heteroclitic" have become to be introduced in this review, although they were not always directly related to immuno-biological works on poly(ADP-ribose). Also, I tried to speculate on the future prospects of poly(ADP-ribose), product of PARP, as an immuno-regulatory molecule, including either induced or naturally-occurring antibodies, in view of "heteroclitic".

Glatiramer acetate and nanny proteins restrict access of the multiple sclerosis autoantigen myelin basic protein to the 26S proteasome

We recently showed that myelin basic protein (MBP) is hydrolyzed by 26S proteasome without ubiquitination. The previously suggested concept of charge-mediated interaction between MBP and the proteasome led us to attempt to compensate or mimic its positive charge to inhibit proteasomal degradation. We demonstrated that negatively charged actin and calmodulin (CaM), as well as basic histone H1.3, inhibit MBP hydrolysis by competing with the proteasome and MBP, respectively, for binding their counterpart. Interestingly, glatiramer acetate (GA), which is used to treat multiple sclerosis (MS) and is structurally similar to MBP, inhibits intracellular and in vitro proteasome-mediated MBP degradation. Therefore, the data reported in this study may be important for myelin biogenesis in both the normal state and pathophysiological conditions.

Gene expression analysis reveals functional pathways of glatiramer acetate activation

BACKGROUND

Glatiramer acetate (GA, Copaxone®), a mixture of polymers comprising four amino acids, is approved for treatment of relapsing-remitting multiple sclerosis and clinically isolated syndrome. GA mediates its activity by induction of GA-specific T cells that shift the T cell balance from a dominant proinflammatory phenotype (Th1/Th17) to an anti-inflammatory phenotype (Th2/Treg).

OBJECTIVE

To characterize the functional pathways by which GA acts on immune cells, the authors conducted gene expression profiling using glatiramoid-stimulated splenocytes.

METHODS

Mice were immunized with GA and harvested splenocytes were reactivated ex vivo with GA or a purported generic GA. Gene expression profiles and functional pathways were evaluated in reactivated splenocytes.

RESULTS

Overall, 1,474 genes were significantly upregulated or downregulated by GA. The main functional pathways induced by GA were: increased proliferation and activation of immune cells including T and B lymphocytes, stimulation of antigen presenting cells and differentiation of effector T lymphocytes. T-helper cell differentiation was the most significant canonical pathway associated with gene transcripts altered by GA. These expression patterns were not observed when splenocytes were activated with generic GA.

CONCLUSION

GA-induced functional pathways coincide with known mechanisms of GA activity in MS patients and further support the unique therapeutic effect of this drug.

Glatiramer acetate in treatment of multiple sclerosis: a toolbox of random co-polymers for targeting inflammatory mechanisms of both the innate and adaptive immune system?

Multiple sclerosis is a disease of the central nervous system, resulting in the demyelination of neurons, causing mild to severe symptoms. Several anti-inflammatory treatments now play a significant role in ameliorating the disease. Glatiramer acetate (GA) is a formulation of random polypeptide copolymers for the treatment of relapsing-remitting MS by limiting the frequency of attacks. While evidence suggests the influence of GA on inflammatory responses, the targeted molecular mechanisms remain poorly understood. Here, we review the multiple pharmacological modes-of-actions of glatiramer acetate in treatment of multiple sclerosis. We discuss in particular a newly discovered interaction between the leukocyte-expressed integrin α(M)β(2) (also called Mac-1, complement receptor 3, or CD11b/CD18) and perspectives on the GA co-polymers as an influence on the function of the innate immune system.

Experimental autoimmune encephalomyelitis: association with mutual regulation of RelA (p65)/NF-κB and phospho-IκB in the CNS

Recently emerging evidence that the NF-κB family plays an important role in autoimmune disease has produced very broad and sometimes paradoxical conclusions. In the present study, we elucidated that the activation of RelA (p65) of NF-κB and IκB dissociation assumes a distinct role in experimental autoimmune encephalomyelitis (EAE) progression by altering IκB phosphorylation and/or degradation. In the present study of factors that govern EAE, the presence and immunoreactivity of nuclear RelA and phospho-IκB were recorded at the initiation and peak stage, and degradation of IκBα progressed rapidly at an early stage then stabilized during recovery. The immunoreactivity to RelA and phospho-IκB occurred mainly in inflammatory cells and microglial cells but only slightly in astrocytes. Subsequently, the blockade of IκB dissociation from NF-κB reduced the severity of disease by decreasing antigen-specific T cell response and production of IL-17 in EAE. Thus, blocking the dissociation of IκB from NF-κB can be utilized as a strategy to inhibit the NF-κB signal pathway thereby to reduce the initiation, progression, and severity of EAE.

Role of γδ T cells in antibody production and recovery from SFV demyelinating disease

Semliki Forest Virus (SFV) encephalomyelitis has been used to study the pathogenesis of virus-induced demyelination and serves as a model for multiple sclerosis. SFV-infection of mice invariably leads to clinical weakness accompanied by CNS inflammation, viral clearance and primary demyelination by day 21 postinfection (pi), followed by recovery and remyelination by day 35 pi. We have applied this model to the examination of the effects of γδ T cells in antibody production and the pathogenesis of demyelinating lesions. SFV-infection of γδ T cell KO mice resulted in more severe clinical signs than in wild type (WT) B6 mice. SFV-infected WT and γδ KO mice both cleared virus by day 10 pi and inflammation was comparable. Demyelination also appeared to be similar in both groups except that KO mice did not exhibit extensive remyelination which was seen in WT mice by day 21. SFV-infected WT mice showed widespread remyelination by day 35 pi, whereas KO mice still displayed some demyelination through day 42 pi. Both WT and KO mice developed serum antibodies to SFV. However, the reactivity of WT sera with the SFV epitope, E2 T(h) peptide₂, was significantly higher than in KO sera. Immunization with E2 T(h) peptide₂ resulted in elevated antibody production to this peptide (p<0.05) and earlier remyelination (day 28 pi) in KO mice. Thus, our study has shown for the first time that immunization of SFV-infected γδ T cell KO mice with a viral peptide, E2 T(h) peptide₂ led to enhanced recovery and repair of the CNS.

Antibody therapy in neurodegenerative disease

Advances in medical science have led to increased life expectancy and increased median age in the population. Because the symptoms of neurodegenerative diseases generally onset in mid- to late-life, a concomitant increase in the number of persons afflicted with these devastating diseases has occurred. Developing therapies for neurodegenerative diseases is of the highest priority due to the enormous cost of medical care required, as well as for the human suffering involved. Although caused by a variety of genetic and environmental insults, such diseases share commonalities. Many of these diseases are proteinopathies--diseases caused by misfolded, aggregating proteins. Antibodies that can recognize and remove misfolded proteins are ideally suited for proteinopathy therapeutics. The numerous intriguing advances in antibody-based therapies for neurodegenerative diseases are discussed in this review.

Failure of glatiramer acetate to modify the peripheral T cell repertoire of relapsing-remitting multiple sclerosis patients

Glatiramer acetate (GA) is a random copolymer used as an immunomodulatory treatment in relapsing-remitting multiple sclerosis (RR-MS). Its mechanisms of action are poorly understood, and several hypotheses have been put forward, the majority of which rely on in vitro studies. It has been hypothesised that further to processing by APC, GA could provide a large number of different epitopes with a possible sequence similarity to auto-antigens, which are able to stimulate a large proportion of T cells. Given that in a previous study we showed that the circulating T cells of MS patients present more alterations of the Vbeta T cell receptor (TCR) usage than normal individuals, we explored the possible effect of GA on the ex vivo T cell repertoire of MS patients. Here we used quantitative PCR and electrophoresis to longitudinally analyse (and without any ex vivo stimulation), the CDR3 length distribution (LD) and the amount of Vbeta TCR, as well as various cytokines, in the blood T cells of 10 RR-MS patients before and after 3 months and 2 years of GA treatment. In addition, we also determined the status of responder and non-responder patients after 24 months of GA treatment based on clinical and radiological criteria. We found no significant modification of cytokine production, Vbeta TCR mRNA accumulation or CDR3-LD in the patients after short-term and long-term treatment. In addition, we did not observe any difference in CDR3-LD in the GA responder patients (n=6) compared to non-responder patients (n=4). Focusing our study on responder patients, we performed TCR repertoire analysis in the CD4+ and CD8+ compartment. Alterations of CDR3-LD were predominantly found in the CD8+ compartment, without any significant influence of GA treatment. Finally, the T cell repertoire variations in MS patients treated with GA and healthy controls were equivalent. Collectively, our data suggest that GA therapy does not induce significant variations in cytokine production or TCR usage in MS patients.

Glatiramer acetate immunization induces specific antibody and cytokine responses in ALS patients

We assessed humoral and cytokine responses in monthly plasma samples from ALS patients who received glatiramer acetate (GA) immunization every day or every other week, or remained untreated (control) from a six-month phase II trial. Samples were evaluated by GA-specific ELISA assays for detection of combined immunoglobulin (Ig) classes (IgM,A,G), IgG alone, and IgG subclasses (IgG1, IgG2, IgG3, and IgG4). T-helper (Th) type 1 and 2 (Th1 and Th2) cytokine levels were determined by flow cytometric cytokine bead arrays. Fourteen of 21 GA-immunized patients produced anti-GA Ig responses. Those treated every day produced anti-GA responses within one month, while those treated every other week exhibited responses by month two. All anti-GA IgG subclass concentrations were increased in excess of 4.2-fold in plasma from treated patients, and anti-GA IgG1 comprised the majority of the humoral response. Mean plasma cytokine levels were statistically indistinguishable between treatment regimens; however, stratification by patient and time on study showed more prevalent trends in changes of Th1 or Th2 cytokine levels following GA treatment every other week or every day, respectively. These data show significant humoral responses and cytokine trends following GA immunization in ALS patients.

Comparison of subcutaneous interferon beta-1a with glatiramer acetate in patients with relapsing multiple sclerosis (the REbif vs Glatiramer Acetate in Relapsing MS Disease [REGARD] study): a multicentre, randomised, parallel, open-label trial

BACKGROUND

Interferon beta-1a and glatiramer acetate are commonly prescribed for relapsing-remitting multiple sclerosis (RRMS), but no published randomised trials have directly compared these two drugs. Our aim in the REGARD (REbif vs Glatiramer Acetate in Relapsing MS Disease) study was to compare interferon beta-1a with glatiramer acetate in patients with RRMS.

METHODS

In this multicentre, randomised, comparative, parallel-group, open-label study, patients with RRMS diagnosed with the McDonald criteria who had had at least one relapse within the previous 12 months were randomised to receive 44 mug subcutaneous interferon beta-1a three times per week or 20 mg subcutaneous glatiramer acetate once per day for 96 weeks to assess the time to first relapse. A subpopulation of 460 patients (230 from each group) also had serial MRI scans to assess T2-weighted and gadolinium-enhancing lesion number and volume. Treatments were assigned by a computer-generated randomisation list that was stratified by centre. Analysis was by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT00078338.

FINDINGS

Between February and December, 2004, 764 patients were randomly assigned: 386 to interferon beta-1a and 378 to glatiramer acetate. After 96 weeks, there was no significant difference between groups in time to first relapse (hazard ratio 0.94, 95% CI 0.74 to 1.21; p=0.64). Relapse rates were lower than expected: 258 patients (126 in the interferon beta-1a group and 132 in the glatiramer acetate group) had one or more relapses (the expected number was 460). For secondary outcomes, there were no significant differences for the number and change in volume of T2 active lesions or for the change in the volume of gadolinium-enhancing lesions, although patients treated with interferon beta-1a had significantly fewer gadolinium-enhancing lesions (0.24 vs 0.41 lesions per patient per scan, 95% CI -0.4 to 0.1; p=0.0002). Safety and tolerability profiles were consistent with the known profiles for both compounds. The overall number and severity of adverse events were similar between the treatments and were not an important cause for discontinuation of the trial during the 96 weeks.

INTERPRETATION

There was no significant difference between interferon beta-1a and glatiramer acetate in the primary outcome. The ability to predict clinical superiority on the basis of results from previous studies might be limited by a trial population with low disease activity, which is an important consideration for ongoing and future trials in patients with RRMS.

Remyelination-promoting human IgMs: developing a therapeutic reagent for demyelinating disease

Promoting remyelination following injury to the central nervous system (CNS) promises to be an effective neuroprotective strategy to limit the loss of surviving axons and prevent disability. Studies confirm that multiple sclerosis (MS) and spinal cord injury lesions contain myelinating cells and their progenitors. Recruiting these endogenous cells to remyelinate may be of therapeutic value. This review addresses the use of antibodies reactive to CNS antigens to promote remyelination. Antibody-induced remyelination in a virus-mediated model of chronic spinal cord injury was initially observed in response to treatment with CNS reactive antisera. Monoclonal mouse and human IgMs, which bind to the surface of oligodendrocytes and myelin, were later identified that were functionally equivalent to antisera. A recombinant form of a human remyelination-promoting IgM (rHIgM22) targets areas of CNS injury and promotes maximal remyelination within 5 weeks after a single low dose (25 microg/kg). The IgM isoform of this reparative antibody is required for in vivo function. We hypothesize that the IgM clusters membrane domains and associated signaling molecules on the surface of target cells. Current therapies for MS are designed to modulate inflammation. In contrast, remyelination promoting IgMs are the first potential therapeutic molecules designed to induce tissue repair by acting within the CNS at sites of damage on the cells responsible for myelin synthesis.

Copaxone interferes with the PrP Sc-GAG interaction

The hallmark of prion disease-induced neurodegeneration is the accumulation of PrP(Sc), a misfolded form of PrP(C). In addition, several lines of evidence indicate a role for the immune system and, in particular, inflammation in prion disease pathogenesis. In this work, we tested whether Copaxone, an immunomodulatory agent currently used for the treatment of multiple sclerosis, can affect prion disease manifestation in scrapie-infected hamsters. We show here that Copaxone exerted no effect on prion disease incubation time when treatment commenced 2 weeks after i.p. prion infection. However, when Copaxone was mixed with the initial prion inoculum or administered to hamsters weekly starting on the day of infection, prion disease incubation time was prolonged by 30 days. This suggests that Copaxone may affect the initial infection process. In vitro experiments indicate that Copaxone significantly reduced PrP(Sc) binding to both Chinese hamster ovary (CHO) cells and heparin beads and also binds to heparin by itself. Interestingly, Copaxone also abolished PrP(Sc) accumulation in scrapie-infected cells. We propose that Copaxone delays prion infection by competing with the PrP(Sc)-glycosaminoglycans interaction. Whether the immunomodulating activity of Copaxone is related to its heparin binding and anti-prion properties remains to be established.

An immuno-PF2D-MS/MS proteomic approach for bacterial antigenic characterization: to Bacillus and beyond

We are confronted daily to unknown microorganisms that have yet to be characterized, detected, and/or analyzed. We propose, in this study, a multidimensional strategy using polyclonal antibodies, consisting of a novel proteomic tool, the ProteomeLab PF2D, coupled to immunological techniques and mass spectrometry (i-PF2D-MS/MS). To evaluate this strategy, we have applied it to Bacillus subtilis, considered here as our unknown bacterial model.

Immunomodulatory vaccines against autoimmune diseases

Vaccines are for healthy people, to prevent them from becoming ill. Such prophylactic vaccines have been a great success. Therapeutic vaccines become more and more important, especially as life expectancy increases. Efforts to develop vaccines against such diseases as cancer, AIDS, hepatitis, tuberculosis, Alzheimer disease, and mad cow disease have not yet reached the stage where they can be successfully used on a daily basis. However, significant progress has been made in the realm of autoimmune diseases, resulting (at least in one case) in an immunomodulatory vaccine against multiple sclerosis that was developed in the author's laboratory, and that is in daily use by about 100,000 patients. The drug or therapeutic vaccine against the exacerbating-remitting type of multiple sclerosis is a copolymer of four amino acid residues, denoted Copaxone, which are related to myelin basic protein. This paper discusses Copaxone as well as a candidate immunomodulatory vaccine against myasthenia gravis, a peptide derived from the nicotinic acetylcholine receptor. Copolymer 1 (Cop 1, glatiramer acetate, Copaxone) is a synthetic amino acid random copolymer that is immunologically cross-reactive with myelin basic protein and suppresses experimental allergic encephalomyelitis in several animal species. Cop 1 slows the progression of disability and reduces the relapse rate in exacerbating-remitting multiple sclerosis patients. Cop 1 is a potent inducer of T helper 2 (Th2) regulatory cells in mice and humans; and Th2 cells are found in both the brains and spinal cords of Cop 1-treated mice and humans. MG and experimental autoimmune MG are T cell-regulated, antibody-mediated autoimmune diseases. Two peptides, representing sequences of the human AChR-alpha-subunit, p195-212 and p259-271, are immunodominant T-cell epitopes in MG patients and two strains of mice. Altered peptide ligand, composed of the randomly arranged two single amino acid analogs inhibits in vitro and in vivo MG-associated autoimmune responses. The active suppression is mediated by the CD4+ CD25+ immunoregulatory cells and is associated with the downregulation of Th1-type cytokines and upregulation of the secretion of IL-10 and the immunosuppressive cytokine transforming growth factor beta.

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

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.

Contribution of peptides to multiple sclerosis research

Multiple sclerosis (MS) is an autoimmune disease associated with chronic inflammatory demyelination of the central nervous system in genetically susceptible individuals. Because of the disease complexity and heterogeneity, its pathogenesis remains unknown despite extensive research efforts, and specific effective treatments have not yet been developed. Peptide-based research has been important in attempts to unravel particular aspects of this complex disease, including the characterization of the different molecular mechanisms of MS, with the goal of providing useful products for immune-mediated therapies. In fact, in the past decade, peptide-based research has been predominant in research aimed to identify and/or develop target antigens as synthetic probes for specific biomarkers as well as innovative immunomodulating therapies. This review presents an overview of the contributions of peptide science to MS research and discusses future directions of peptide-based investigations.

Glatiramer acetate in multiple sclerosis: update on potential mechanisms of action

Glatiramer acetate is a synthetic random copolymer approved for the immunomodulatory therapy of relapsing-type multiple sclerosis (MS). Previous work has focused on the effects of this drug on T cells, especially the glatiramer-acetate-induced shift of the cytokine profile towards those characteristic of T-helper-2 (Th2) cells. Glatiramer acetate was thought to bring about this Th2 shift by acting like an altered peptide ligand but more recent work has shown that the drug notably affects the properties of antigen-presenting cells, such as monocytes and dendritic cells. These new observations might offer an explanation for the previously observed Th2 shift. In this review, we focus on these new findings. We address several controversial issues, including the possible neurotrophic effects of glatiramer acetate, the potential role of neutralising antibodies to the drug, and attempts to develop biomarkers of the treatment response. Finally, we will think about how a better understanding of glatiramer acetate might help the development of new immunomodulatory agents for MS.

Therapeutic vaccines in autoimmunity

Similarly to prophylactic vaccines whose purpose is to prevent infectious diseases, therapeutic vaccines against autoimmune diseases are based on their similarity to the putative causes of the disease. We shall describe here two such examples: a copolymer of amino acids related to myelin basic protein, in the case of multiple sclerosis, and a peptide derived from the nicotinic acetylcholine receptor (AChR), in the case of myasthenia gravis (MG). Copolymer 1 (Cop 1, glatiramer acetate, Copaxone) is a synthetic amino acid random copolymer, immunologically cross-reactive with myelin basic protein and suppresses experimental allergic encephalomyelitis in several animal species. Cop 1 slows the progression of disability and reduces relapse rate in exacerbating-remitting multiple sclerosis patients. It was approved by the Food and Drug Administration in 1996, and today is used by tens of thousands of patients. Cop 1 is a potent inducer of T helper 2 (Th2) regulatory cells in mice and humans, and Th2 cells are found both in the brains and spinal cords of Cop 1-treated mice. MG and experimental autoimmune MG are T cell-regulated, antibody-mediated autoimmune diseases. Two peptides, representing sequences of the human AChR alpha-subunit, p195-212 and p259-271, are immunodominant T cell epitopes in MG patients and in two strains of mice. Altered peptide ligand, composed of the tandemly arranged two single amino acid analogs, inhibits in vitro and in vivo MG-associated autoimmune responses. The active suppression is mediated by the CD4(+)CD25(+) immunoregulatory cells and is associated with the down-regulation of Th1-type cytokines and the up-regulation of the secretion of IL-10 and the immunosuppressive cytokine, transforming growth factor beta.

Immunomodulation by the copolymer glatiramer acetate

Glatiramer acetate (GA; Copaxone, also known as Copolymer 1 or Cop-1), a copolymer of amino acids, is very effective in the suppression of experimental autoimmune encephalitis (EAE), the animal model for multiple sclerosis (MS), in various species including primates. The immunological cross-reaction between the myelin basic protein and GA serves as the basis for the suppressive activity of GA in EAE, by the induction of antigen-specific suppressor cells. The mode of action of GA is by initial strong promiscuous binding to major histocompatibility complex class II molecules and competition with MBP and other myelin proteins for such binding and presentation to T cells. Suppressor T cells induced by GA are of the Th2 type, migrate to the brain and lead to in situ bystander suppression. Clinical trials with GA, both phase II and phase III, were performed in relapsing-remitting MS (RRMS) patients, and demonstrated efficacy in reducing the relapse rate, decreasing MRI-assessed disease activity and burden and slowing progression of disability. GA is generally well tolerated and is not associated with influenza-like symptoms and formation of neutralizing antibodies seen with beta-interferons. It exerts its suppressive effect primarily by immunomodulation, and has recently shown ameliorating effect in a few additional autoimmune disorders as well as in graft rejection. At present GA is considered a valuable first-line treatment option for patients with RRMS.

Antibodies to glatiramer acetate do not interfere with its biological functions and therapeutic efficacy

Glatiramer acetate (GA) previously known as Copolymer 1 (Cop 1), a synthetic amino acid copolymer, suppresses experimental autoimmune encephalomyelitis (EAE) and shows a beneficial effect in relapsing-remitting type of multiple sclerosis (MS). GA acts as a specific immunomodulator by binding to MHC Class II molecules, inducing specific T suppressor (Ts) cells and interfering with T cell responses to myelin antigens. MS patients treated with GA developed GA reactive antibodies, which peaked at three months and decreased at six months. In order to find out whether anti-GA antibodies may neutralize the therapeutic effect of GA, we tested both polyclonal (mouse and human) and monoclonal GA specific antibodies for their ability to interfere with the biological activity of GA in several assay systems. None of the antibodies interfered with GA activities either in vitro (binding to MHC molecules and T cell stimulation) or in vivo (blocking of EAE). Furthermore, 53 samples of sera obtained from 34 MS patients that participated in the open label trial in Israel, and all developed GA specific antibodies, were tested for their ability to inhibit the proliferation response of GA specific Ts cell clone and to interfere with GA competitive inhibition of the response to peptide 84-102 of myelin basic protein (MBP). None of the sera inhibited and some even enhanced the in vitro activities of GA. Furthermore, representative MS sera with high titer of GA reactive antibodies did not neutralize the biological activities of GA and did not inhibit Th2 cytokine secretion by human GA specific clone. These results are consistent with the findings that the therapeutic effect of GA is not affected by GA reactive antibodies and is sustained upon long term treatment.

Glatiramer acetate (Copaxone) regulates nitric oxide and related cytokine secretion in experimental autoimmune encephalomyelitis

Nitric oxide (NO) is an important mediator involved in the pathogenesis of experimental autoimmune encephalomyelitis (EAE) and multiple sclerosis (MS). We examined the effect of glatiramer acetate (GA), an agent with suppressing effect on EAE and of therapeutic value for the treatment of MS, on the secretion of NO, as well as of the NO regulating cytokines. We observed that induction of EAE leads to 4-fold elevation in NO secretion and that treatment of the EAE mice by GA indeed leads to a significant reduction in the NO secretion by the splenocytes in response to the encephalitogen. A parallel decrease was observed in the secretion of the NO inducing cytokine IL-1beta. On the other hand, the secretion level of NO modulating cytokines IL-10 and IL-13 was significantly augmented. The correlation between these findings and the therapeutic effect of GA is discussed.

Effects of glatiramer acetate on relapse rate and accumulated disability in multiple sclerosis: meta-analysis of three double-blind, randomized, placebo-controlled clinical trials

Three randomized, double-blind, placebo-controlled trials have shown that glatiramer acetate (GA) is effective in reducing relapse rate in patients with relapsing-remitting (RR) multiple sclerosis (MS). Using raw data pooled from 540 patients, we performed a meta-analysis of these three trials, to investigate whether the extent of GA efficacy varies according to disease-related variables at study entry. Three regression models were developed to assess the efficacy of GA on the annualized relapse rate (primary outcome measure), on the total number of on-trial relapses and on the time to first relapse. We also explored the efficacy of GA on accumulated disability and the potential role of baseline clinical variables as predictors of relapse-rate variables and treatment efficacy. The mean adjusted annualized relapse rate on study was 1.14 in the pooled placebo-treated subjects and 0.82 in the pooled GA group (P = 0.004), indicating an average reduction in annualized relapse rate of 28%. About a one third reduction of the total number of on-trial relapses was also observed in patients receiving GA (P < 0.0001), who had a median time to the first relapse of 322 days versus a median time to the first relapse of 219 days seen in those receiving placebo (P = 0.01). A beneficial effect on accumulated disability was also found (risk ratio of 0.6; 95%; CI = 0.4-0.9; P = 0.02). The drug assignment (P = 0.004), baseline EDSS score (P = 0.02) and number of relapses during the two years prior to study entry (P = 0.002) were significant predictors of on-trial annualized relapse rate. No other demographic or clinical variable at baseline significantly influenced the treatment effect. This meta-analysis reaffirms the effectiveness of GA in reducing relapse rate and disability accumulation in RRMS, at a magnitude comparable to that of other available immunomodulating treatments. It also suggests that GA efficacy is not significantly influenced by the patients' clinical characteristics at the time of treatment initiation.

Glatiramer acetate (Copaxone) therapy for multiple sclerosis

Glatiramer acetate (GA) (Copaxone(R)) is a worldwide-approved drug for the treatment of relapsing multiple sclerosis (MS), an autoimmune disease of the CNS. The drug is a synthetic copolymer with an amino acid composition based on the structure of myelin basic protein, one of the autoantigens implicated in the pathogenesis of MS and experimental autoimmune encephalomyelitis (EAE). Developed initially as a "tool" to study EAE, the drug unexpectedly inhibited disease and was subsequently developed for the treatment of MS. The drug has been shown in controlled clinical trials to significantly reduce relapse rate and progression of disability in MS with long-term efficacy, remarkable safety, and tolerability. Efficacy as measured by magnetic resonance imaging parallels its clinical benefits as manifested by a reduction in gadolinium-enhancing lesions and brain atrophy. The mechanism of action of the drug in humans is believed to involve the induction of glatiramer-reactive regulatory cells, including CD4+ and CD8+ T-cells. Glatiramer-reactive Th2 cells are believed to enter the brain and, through cross-reactivity with myelin antigens, produce bystander suppression, antiinflammatory effects, and neuroprotection.

Heterogeneity of pathogenesis in multiple sclerosis: implications for promotion of remyelination

Enhancing myelin repair remains an important therapeutic goal in primary demyelinating diseases of the central nervous system (CNS) such as multiple sclerosis (MS). The emerging heterogeneity of pathology within MS lesions, and differential oligodendrocyte survival in particular, suggests that therapeutic strategies may need to be tailored to an individual patient's requirements. A number of therapeutic strategies have been proposed to enhance myelin repair in the CNS: cell transplantation, growth factor therapy, and antibody therapy, but each proposed therapy has different implications with respect to pathogenetic mechanisms of demyelination. Of these, antibody therapy is the most amenable to immediate application in patients-but a combination of therapeutic approaches may be required in practice.

Oral tolerance to copolymer 1 in myelin basic protein (MBP) TCR transgenic mice: cross-reactivity with MBP-specific TCR and differential induction of anti-inflammatory cytokines

Oral tolerance to myelin basic protein (MBP) is an effective antigen-specific method to suppress experimental allergic encephalomyelitis (EAE). Glatiramer acetate [copolymer 1 (Cop1)] is a synthetic copolymer designed to mimic MBP which suppresses EAE, is used parenterally to treat multiple sclerosis (MS) and is being tested orally for efficacy in MS. We investigated the immunologic properties of Cop1 to determine the degree to which its effects were antigen specific using MBP TCR transgenic mice. Immunization of MBP TCR transgenic mice fed Cop1, MBP or MBP Ac1-11 resulted in decreased proliferation, and IL-2, IL-6 and IFN-gamma production, and increased secretion of IL-10 and transforming growth factor (TGF)-beta in Cop1-fed animals. IFN-gamma was decreased, and IL-10 and TGF-beta were increased in non-immunized mice fed Cop1 and stimulated in vitro with MBP. No such effects were observed in ovalbumin TCR transgenic mice. To determine if the effects of Cop1 were specific to MBP TCR-bearing cells, MBP TCR transgenic Rag2(-/-) mice were immunized and re-stimulated in vitro with Cop1. We found a marked increase in IL-4 and similar increases in IL-4 after feeding Cop1. In disease models, feeding Cop1 suppressed EAE in MBP TCR transgenic mice, (PL/J x SJL)F(1) mice, and in myelin oligodendrocyte glycoprotein-induced EAE in NOD mice. Oral Cop1 had no effect on collagen-induced arthritis. These results demonstrate that Cop1 is active orally in an antigen-specific fashion, and may function as an altered peptide ligand for MBP-specific TCR-bearing cells by decreasing pro-inflammatory cytokines (IFN-gamma) and increasing anti-inflammatory cytokines (IL-4, IL-10 and TGF-beta).

Expression of urokinase plasminogen activator receptor on monocytes from patients with relapsing-remitting multiple sclerosis: effect of glatiramer acetate (copolymer 1)

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system in which peripheral blood monocytes play an important role. We have previously reported that patients with chronic progressive MS (CPMS) have significantly increased numbers of circulating monocytes which express the urokinase plasminogen activator receptor (uPAR). In the present study, we examined the expression of uPAR on monocytes in patients with relapsing-remitting multiple sclerosis (RRMS) not currently participating in a clinical trial and in patients with RRMS who were enrolled in a double-blind multicenter clinical trial designed to examine the effect of glatiramer acetate (copolymer 1; Copaxone) on relapsing disease. Patients with CPMS have sustained high levels of circulating uPAR-positive (uPAR(+)) monocytes. In comparison, patients with RRMS displayed variable levels of circulating uPAR(+) monocytes. Mean values for uPAR in patients with RRMS were above those seen for controls but were not as high as those observed for patients with secondary progressive MS. Patients with RRMS in the clinical trial also had variable levels of monocyte uPAR. However, patients in the treatment group displayed lower levels following 2 years of treatment. In both placebo-treated and glatiramer acetate-treated patients, the percentage of circulating uPAR(+) monocytes, as well as the density of uPAR expressed per cell (mean linear fluorescence intensity), increased just prior to the onset of a clinically documented exacerbation. Values fell dramatically with the development of clinical symptoms. uPAR levels in all groups correlated with both clinical activity and severity. Results indicate that monocyte activation is impatient in MS and that glatiramer acetate may have a significant effect on monocyte activation in patients with RRMS.

Glatiramer acetate in the treatment of multiple sclerosis

This review article summarises the initial preclinical studies as well as the different stages of clinical trials in multiple sclerosis (MS) with Copolymer 1 (Cop 1), recently denoted glatiramer acetate. Experimental studies on autoimmune encephalomyelitis (EAE), the animal model of MS, as well as studies on the mechanism of action in both animals and humans are discussed. The review describes the early clinical trials which were followed by Phase II and III trials, culminating in FDA approval in 1996 for the treatment of relapsing-remitting MS. The accumulated experience with glatiramer acetate indicates that its efficacy is apparently increased as a function of usage time while the favourable side effect profile is sustained. MRI studies revealed that treatment with glatiramer acetate resulted in a significant reduction of gadolinium (Gd)-enhancing lesions. Ongoing clinical trials which might extend its usage or change its mode of delivery are also described. Glatiramer acetate appears to be a treatment of choice for the relapsing-remitting type of MS.

Humoral and cellular immune responses to Copolymer 1 in multiple sclerosis patients treated with Copaxone

Humoral and cellular immune responses were followed in multiple sclerosis patients treated with Copolymer 1 (Cop1, glatiramer acetate, Copaxone) who participated in three different clinical trials. All patients (130) developed Cop1 reactive antibodies, which peaked at 3 months after initiation of treatment, decreasing at 6 months and remaining low. IgG1 antibody levels were 2-3-fold higher than those of IgG2. The proliferative response of Peripheral Blood Mononuclear Cells (PBMC) to Cop1 was initially high and gradually decreased during treatment. Antibodies and T cell responses to MBP were low and did not change significantly during the treatment. The humoral and cellular immunological responses to Cop1 do not correlate with the side effects and do not affect its therapeutic activity. The preferential production of IgG1 over IgG2 antibodies may indicate that Th2 responses are involved in mediating the clinical effect of Cop1.

The concept of specific immune treatment against autoimmune diseases

Copolymer 1 (Cop 1, Copaxone) is a synthetic amino acid copolymer effective in suppression of experimental allergic encephalomyelitis (EAE). The suppressive effect of Cop 1 in EAE is not restricted to a certain species, disease type or encephalitogen used for EAE induction. In phases II and III clinical trials Cop 1 was found to slow progression of disability and reduce the relapse rate in exacerbating-remitting multiple sclerosis (MS) patients. To extend this concept we have more recently shown that a similar approach is possible in the case of myasthenia gravis. We used two myasthenogenic T cell epitopes of the human acetylcholine receptor alpha-subunit and demonstrated that they are capable of triggering peripheral blood lymphocytes of the majority (>80%) of myasthenic patients tested. Both single amino acid analogs, and a dual analog composed of the tandemly arranged two single amino acid analogs were able to inhibit in vitro proliferative responses of T cell lines, and in vivo priming of lymph node cells. The dual analog inhibited experimental autoimmune myasthenia gravis even when the mice were treated fourteen days after the injection of the pathogenic T cell line.

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

The synthetic random amino acid copolymer Copolymer 1 (Cop 1, Copaxone, glatiramer acetate) suppresses experimental autoimmune encephalomyelitis, slows the progression of disability, and reduces relapse rate in multiple sclerosis (MS). Cop 1 binds to various class II major histocompatibility complex (MHC) molecules and inhibits the T cell responses to several myelin antigens. In this study we attempted to find out whether, in addition to MHC blocking, Cop 1, which is immunologically cross-reactive with myelin basic protein (MBP), inhibits the response to this autoantigen by T cell receptor (TCR) antagonism. Two experimental systems, "prepulse assay" and "split APC assay," were used to discriminate between competition for MHC molecules and TCR antagonism. The results in both systems using T cell lines/clones from mouse and human origin indicated that Cop 1 is a TCR antagonist of the 82-100 epitope of MBP. In contrast to the broad specificity of the MHC blocking induced by Cop 1, its TCR antagonistic activity was restricted to the 82-100 determinant of MBP and could not be demonstrated for proteolipid protein peptide or even for other MBP epitopes. Yet, it was shown for all the MBP 82-100-specific T cell lines/clones tested that were derived from mice as well as from an MS patient. The ability of Cop 1 to act as altered peptide and induce TCR antagonistic effect on the MBP p82-100 immunodominant determinant response elucidates further the mechanism of Cop 1 therapeutic activity in experimental autoimmune encephalomyelitis and MS.

Bystander suppression of experimental autoimmune encephalomyelitis by T cell lines and clones of the Th2 type induced by copolymer 1

The synthetic amino acid copolymer, copolymer 1 (Cop 1) induces T suppressor (Ts) lines/clones, which are confined to the Th2 pathway, cross react with myelin basic protein (MBP), but not with other myelin antigens on the level of Th2 cytokine secretion. Nevertheless, Cop 1 Ts cells inhibited the IL-2 response of a proteolipid protein (PLP) specific line. Furthermore, Cop 1 Ts cells ameliorated EAE induced by two unrelated encephalitogenic epitopes of PLP: p139-151 and p178-191, that produced different forms of disease. This bystander suppression demonstrated by the Cop 1 Ts cells may explain the therapeutic effect of Cop 1 in EAE and MS.

Copolymer 1 induces T cells of the T helper type 2 that crossreact with myelin basic protein and suppress experimental autoimmune encephalomyelitis

The synthetic amino acid copolymer copolymer 1 (Cop 1) suppresses experimental autoimmune encephalomyelitis (EAE) and is beneficial in multiple sclerosis. To further understand Cop 1 suppressive activity, we studied the cytokine secretion profile of various Cop 1-induced T cell lines and clones. Unlike T cell lines induced by myelin basic protein (MBP), which secreted either T cell helper type 1 (Th1) or both Th1 and Th2 cytokines, the T cell lines/clones induced by Cop 1 showed a progressively polarized development toward the Th2 pathway, until they completely lost the ability to secrete Th1 cytokines. Our findings indicate that the polarization of the Cop 1-induced lines did not result from the immunization vehicle or the in vitro growing conditions, but rather from the tendency of Cop 1 to preferentially induce a Th2 response. The response of all of the Cop 1 specific lines/clones, which were originated in the (SJL/JxBALB/c)F1 hybrids, was restricted to the BALB/c parental haplotype. Even though the Cop 1-induced T cells had not been exposed to the autoantigen MBP, they crossreacted with MBP by secretion of interleukin (IL)-4, IL-6, and IL-10. Administration of these T cells in vivo resulted in suppression of EAE induced by whole mouse spinal cord homogenate, in which several autoantigens may be involved. Secretion of anti-inflammatory cytokines by Cop 1-induced suppressor cells, in response to either Cop 1 or MBP, may explain the therapeutic effect of Cop 1 in EAE and in multiple sclerosis.

Cop 1 as a candidate drug for multiple sclerosis

Copolymer 1 (Cop 1), a synthetic copolymer of amino acids, is very effective in suppression of experimental autoimmune encephalomyelitis (EAE), the animal model for multiple sclerosis (MS). Cop 1 was found incapable of inducing EAE, yet it suppressed EAE in a variety of animal species, including primates. The immunological cross-reaction between the myelin basic protein (MBP) and Cop 1 serves as the basis for the suppressive activity of Cop 1 in EAE, by the induction of antigen-specific suppressor cells and competition with MBP for binding to major histocompatibility complex (MHC) molecules. Clinical trials with Cop 1, both Phase II and Phase III, were performed in relapsing-remitting (E-R) patients. The latter, a two-year multicenter double blind trial with 251 participating patients was conducted at 11 leading medical centers in the USA. It demonstrated a significant beneficial effect of Cop 1 in both diminishing the rate of exacerbations and improving the clinical status. The side effects of Cop 1 were only minimal. The cumulative results indicate that Cop 1 is a promising candidate drug for multiple sclerosis.

Management of relapsing/remitting multiple sclerosis with copolymer 1 (Copaxone)

Copolymer I (Copazone) was evaluated in a multicenter, placebo-controlled, double-blind trial at 11 universities. Two hundred and fifty-one relapsing-remitting ambulatory MS patients were randomized to receive 20 mg of copolymer I or placebo by daily subcutaneous injection for approximately 30 months. At conclusion, the copolymer I group had 32% fewer relapses (P = 0.002) and significantly more were relapse-free (P = 0.035). Significantly, more patients were receiving copolymer I had improved during the study, while more patients on placebo showed neurological decline (P = 0.001). There were few side effects and no drug related laboratory abnormalities. Copolymer I is being considered by North American and European regulatory agencies for approval as commercially available agent for the control of multiple sclerosis.