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

Repurposing of glatiramer acetate to treat cardiac ischemia in rodent models

Myocardial injury may ultimately lead to adverse ventricular remodeling and development of heart failure (HF), which is a major cause of morbidity and mortality worldwide. Given the slow pace and substantial costs of developing new therapeutics, drug repurposing is an attractive alternative. Studies of many organs, including the heart, highlight the importance of the immune system in modulating injury and repair outcomes. Glatiramer acetate (GA) is an immunomodulatory drug prescribed for patients with multiple sclerosis. Here, we report that short-term GA treatment improves cardiac function and reduces scar area in a mouse model of acute myocardial infarction and a rat model of ischemic HF. We provide mechanistic evidence indicating that, in addition to its immunomodulatory functions, GA exerts beneficial pleiotropic effects, including cardiomyocyte protection and enhanced angiogenesis. Overall, these findings highlight the potential repurposing of GA as a future therapy for a myriad of heart diseases.

Disease Modifying Strategies in Multiple Sclerosis: New Rays of Hope to Combat Disability?

Multiple sclerosis (MS) is the most prevalent chronic autoimmune inflammatory- demyelinating disorder of the central nervous system (CNS). It usually begins in young adulthood, mainly between the second and fourth decades of life. Usually, the clinical course is characterized by the involvement of multiple CNS functional systems and by different, often overlapping phenotypes. In the last decades, remarkable results have been achieved in the treatment of MS, particularly in the relapsing- remitting (RRMS) form, thus improving the long-term outcome for many patients. As deeper knowledge of MS pathogenesis and respective molecular targets keeps growing, nowadays, several lines of disease-modifying treatments (DMT) are available, an impressive change compared to the relative poverty of options available in the past. Current MS management by DMTs is aimed at reducing relapse frequency, ameliorating symptoms, and preventing clinical disability and progression. Notwithstanding the relevant increase in pharmacological options for the management of RRMS, research is now increasingly pointing to identify new molecules with high efficacy, particularly in progressive forms. Hence, future efforts should be concentrated on achieving a more extensive, if not exhaustive, understanding of the pathogenetic mechanisms underlying this phase of the disease in order to characterize novel molecules for therapeutic intervention. The purpose of this review is to provide a compact overview of the numerous currently approved treatments and future innovative approaches, including neuroprotective treatments as anti-LINGO-1 monoclonal antibody and cell therapies, for effective and safe management of MS, potentially leading to a cure for this disease.

Repurposing MS immunotherapies for CIDP and other autoimmune neuropathies: unfulfilled promise or efficient strategy?

Despite advances in the treatment of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and other common autoimmune neuropathies (AN), still-many patients with these diseases do not respond satisfactorily to the available treatments. Repurposing of disease-modifying therapies (DMTs) from other autoimmune conditions, particularly multiple sclerosis (MS) and neuromyelitis optica spectrum disorders (NMOSD), is a promising strategy that may accelerate the establishment of novel treatment choices for AN. This approach appears attractive due to homologies in the pathogenesis of these diseases and the extensive post-marketing experience that has been gathered from treating MS and NMOSD patients. The idea is also strengthened by a number of studies that explored the efficacy of DMTs in animal models of AN but also in some CIDP patients. We here review the available preclinical and clinical data of approved MS therapeutics in terms of their applicability to AN, especially CIDP. Promising therapeutic approaches appear to be B cell-directed and complement-targeting strategies, such as anti-CD20/anti-CD19 agents, Bruton's tyrosine kinase inhibitors and anti-C5 agents, as they exert their effects in the periphery. This is a major advantage because, in contrast to MS, their action in the periphery is sufficient to exert significant immunomodulation.

Lymphocyte Counts and Multiple Sclerosis Therapeutics: Between Mechanisms of Action and Treatment-Limiting Side Effects

Although the detailed pathogenesis of multiple sclerosis (MS) is not completely understood, a broad range of disease-modifying therapies (DMTs) are available. A common side effect of nearly every MS therapeutic agent is lymphopenia, which can be both beneficial and, in some cases, treatment-limiting. A sound knowledge of the underlying mechanism of action of the selected agent is required in order to understand treatment-associated changes in white blood cell counts, as well as monitoring consequences. This review is a comprehensive summary of the currently available DMTs with regard to their effects on lymphocyte count. In the first part, we describe important general information about the role of lymphocytes in the course of MS and the essentials of lymphopenic states. In the second part, we introduce the different DMTs according to their underlying mechanism of action, summarizing recommendations for lymphocyte monitoring and definitions of lymphocyte thresholds for different therapeutic regimens.

Synthetic Cationic Autoantigen Mimics Glatiramer Acetate Persistence at the Site of Injection and Is Efficacious Against Experimental Autoimmune Encephalomyelitis

A synthetic peptide, K-PLP, consisting of 11-unit poly-lysine (K11) linked via polyethylene glycol (PEG) to proteolipid protein epitope (PLP) was synthesized, characterized, and evaluated for efficacy in ameliorating experimental autoimmune encephalomyelitis (EAE) induced by PLP. K-PLP was designed to mimic the cationic nature of the relapsing-remitting multiple sclerosis treatment, glatiramer acetate (GA). With a pI of ~10, GA is able to form visible aggregates at the site of injection via electrostatic interactions with the anionic extracellular matrix. Aggregation further facilitates the retention of GA at the site of injection and draining lymph nodes, which may contribute to its mechanism of action. K-PLP with a pI of ~11, was found to form visible aggregates in the presence of glycosaminoglycans and persist at the injection site and draining lymph nodes in vivo, similar to GA. Additionally, EAE mice treated with K-PLP showed significant inhibition of clinical symptoms compared to free poly-lysine and to PLP, which are the components of K-PLP. The ability of the poly-lysine motif to retain PLP at the injection site, which increased the local exposure of PLP to immune cells may be an important factor affecting drug efficacy.

HLA Class II Genotype Does Not Affect the Myelin Responsiveness of Multiple Sclerosis Patients

Background: When aiming to restore myelin tolerance using antigen-specific treatment approaches in MS, the wide variety of myelin-derived antigens towards which immune responses are targeted in multiple sclerosis (MS) patients needs to be taken into account. Uncertainty remains as to whether the myelin reactivity pattern of a specific MS patient can be predicted based upon the human leukocyte antigen (HLA) class II haplotype of the patient. Methods: In this study, we analyzed the reactivity towards myelin oligodendrocyte glycoprotein (MOG), myelin basic protein (MBP) and proteolipid protein (PLP) peptides using direct interferon (IFN)-γ enzyme-linked immune absorbent spot (ELISPOT). Next, the HLA class II haplotype profile was determined by next-generation sequencing. In doing so, we aimed to evaluate the possible association between the precursor frequency of myelin-reactive T cells and the HLA haplotype. Results: Reactivity towards any of the analyzed peptides could be demonstrated in 65.0% (13/20) of MS patients and in 60.0% (6/10) of healthy controls. At least one of the MS risk alleles HLA-DRB1*15:01, HLA-DQA1*01:02 and HLA-DQB1*06:02 was found in 70.0% (14/20) of patients and in 20.0% (2/10) of healthy controls. No difference in the presence of a myelin-specific response, nor in the frequency of myelin peptide-reactive precursor cells could be detected among carriers and non-carriers of these risk alleles. Conclusion: No association between HLA haplotype and myelin reactivity profile was present in our study population. This complicates the development of antigen-specific treatment approaches and implies the need for multi-epitope targeting in an HLA-unrestricted manner to fully address the wide variation in myelin responses and HLA profiles in a heterogeneous group of MS patients.

Nano and Microparticle Emerging Strategies for Treatment of Autoimmune Diseases: Multiple Sclerosis and Type 1 Diabetes

Autoimmune diseases affect 10% of the world's population, and 1 in 200 people worldwide suffer from either multiple sclerosis (MS) or type 1 diabetes (T1D). While the targeted organ systems are different, MS and T1D share similarities in terms of autoreactive immune cells playing a critical role in pathogenesis. Both diseases can be managed only symptomatically without curative remission, and treatment options are limited and non-specific. Most current therapies cause some degree of systemic immune suppression, leaving the patients susceptible to opportunistic infections and other complications. Thus, there is considerable interest in the development of immunotherapies not associated with generalized immune suppression for these diseases. This review presents current and preclinical strategies for MS and T1D treatment, emphasizing those aimed to modulate the immune response, including the most recent strategies for tolerance induction. A central focus is on the emerging approaches using nano- and microparticle platforms, their evolution as immunotherapeutic carriers, including those incorporating specific antigens to induce tolerance and reduce unwanted generalized immune suppression.

Glatiramer acetate immune modulates B-cell antigen presentation in treatment of MS

OBJECTIVE

We examined the effect of glatiramer acetate (GA) on B-cell maturation, differentiation, and antigen presentation in MS and experimental autoimmune encephalomyelitis (EAE).

METHODS

A cross-sectional study of blood samples from 20 GA-treated and 18 untreated patients with MS was performed by flow cytometry; 6 GA-treated patients with MS were analyzed longitudinally. GA-mediated effects on B-cell antigen-presenting function were investigated in EAE, or, alternatively, B cells were treated with GA in vitro using vehicle as a control.

RESULTS

In MS, GA diminished transitional B-cell and plasmablast frequency, downregulated CD69, CD25, and CD95 expression, and decreased TNF-α production, whereas IL-10 secretion and MHC Class II expression were increased. In EAE, we observed an equivalent dampening of proinflammatory B-cell properties and an enhanced expression of MHC Class II. When used as antigen-presenting cells for activation of naive T cells, GA-treated B cells promoted development of regulatory T cells, whereas proinflammatory T-cell differentiation was diminished.

CONCLUSIONS

GA immune modulates B-cell function in EAE and MS and efficiently interferes with pathogenic B cell-T cell interaction.

Immunostimulatory effects on THP-1 cells by peptide or protein pharmaceuticals associated with injection site reactions

Injection site reaction (ISR) is a common side-effect associated with the use of peptide or protein pharmaceuticals. These types of pharmaceuticals-induced activation of antigen-presenting cells is assumed to be a key step in the pathogenesis of immune-mediated ISR. The present study was designed to evaluate the immunostimulatory properties of peptide or protein pharmaceuticals using human monocytic THP-1 cells. Here, THP-1 cells, with or without phorbol-12-myristate-13-acetate (PMA) pretreatment, were exposed to enfuvirtide and glatiramer acetate (positive controls) or evolocumab (negative control) for 6 or 24 h. PMA treatment differentiated non-adherent monocytic THP-1 (nTHP-1) cells into adherent macrophagic THP-1 (pTHP-1) cells that highly express CD11b and CD36. Enfuvirtide increased the release of cytokines, e.g. TNFα, MIP-1β, and MCP-1, and expression of CD86 and CD54 on nTHP-1 cells at 24 h. Similar immunostimulatory properties of glatiramer acetate were observed both in the nTHP-1 and pTHP-1 cells at 6 h, but the responses were very weak in the pTHP-1 cells. Evolocumab did not affect cytokine secretion or cell surface marker expression in either cell type. Taken together, these in vitro THP-1 cell assays revealed the immunostimulatory properties of enfuvirtide and glatiramer acetate. This assay platform thus could serve as a powerful tool in evaluating potential immune-related ISR risks of peptide or protein pharmaceuticals in humans.

Understanding regulatory B cells in autoimmune diseases: the case of multiple sclerosis

The suppressive function of B cells is mediated mostly through their provision of cytokines with anti-inflammatory properties, in particular interleukin-10. This B cell activity has been convincingly described in mice with autoimmune, infectious, as well as malignant diseases, and evidence is accumulating of its relevance in human. This review provides a personal view of this B cell function using multiple sclerosis and its animal model experimental autoimmune encephalomyelitis as representative examples, in an attempt to bridge observations obtained in mice and human, with the goal of providing a coherent transversal framework to further explore this field, and eventually manipulate this B cell function therapeutically.

Immunological Aspects of Approved MS Therapeutics

Multiple sclerosis (MS) is the most common neurological immune-mediated disease leading to disability in young adults. The outcome of the disease is unpredictable, and over time, neurological disabilities accumulate. Interferon beta-1b was the first drug to be approved in the 1990s for relapsing-remitting MS to modulate the course of the disease. Over the past two decades, the treatment landscape has changed tremendously. Currently, more than a dozen drugs representing 1 substances with different mechanisms of action have been approved (interferon beta preparations, glatiramer acetate, fingolimod, siponimod, mitoxantrone, teriflunomide, dimethyl fumarate, cladribine, alemtuzumab, ocrelizumab, and natalizumab). Ocrelizumab was the first medication to be approved for primary progressive MS. The objective of this review is to present the modes of action of these drugs and their effects on the immunopathogenesis of MS. Each agent's clinical development and potential side effects are discussed.

A differential sex-specific pattern of IgG2 and IgG4 subclasses of anti-drug antibodies (ADAs) induced by glatiramer acetate in relapsing-remitting multiple sclerosis patients

BACKGROUND

Glatiramer acetate (GA) is a drug for Multiple Sclerosis (MS) treatment. However, its administration induces anti-drug antibodies (ADA). This research evaluated the sex differences in humoral response against GA in RR-MS patients METHODS: We analyzed 69 RR-MS patients, 43 treated with GA and 26 treated with IFN-β. In all cases, the serum concentration of IgG antibodies was determined by UPLC, whereas the levels of IgG subclasses (1-4) of anti-GA antibodies and the concentration of IL-6 were detected by Multiplex and IL-10, and IFN-γ were detected by ELISA.

RESULTS

The total concentration of IgG antibodies in patients did not differ between treatments, whereas the IgG levels of ADA were higher in male and female patients treated with GA (P ≤ 0.0001). The subclasses of IgG anti-GA antibodies were as follows: IgG4>>IgG3>IgG1>IgG2. Statistical analysis showed differences in the IgG2 (P ≤ 0.01) and IgG4 (P ≤ 0.0001) subclasses by sex in RR-MS patients. Levels of IgG1 subclass in male patients correlated positively with the circulatory levels of IL-6 (r_s = 0.587, P ≤ 0.04) and IFN-γ (r_s = 0.721, P ≤ 0.001), while IgG2 subclass levels in female patients correlated with serum levels of IFN-γ (r_s = 0.628, P ≤ 0.0006). Statistical analysis did not detect correlations between the levels of IgG (1-4) subclasses of anti-GA antibodies and the evaluated clinical parameters.

CONCLUSION

This study showed differences in the levels of IgG2 and IgG4 subclasses of ADA between male and female RR-MS patients. Further studies are necessary to take advantage of the clinical potential of this finding.

The Evolving Mechanisms of Action of Glatiramer Acetate

Glatiramer acetate (GA) is a synthetic amino acid copolymer that is approved for treatment of relapsing remitting multiple sclerosis (RRMS) and clinically isolated syndrome (CIS). GA reduces multiple sclerosis (MS) disease activity and has shown comparable efficacy with high-dose interferon-β. The mechanism of action (MOA) of GA has long been an enigma. Originally, it was recognized that GA treatment promoted expansion of GA-reactive T-helper 2 and regulatory T cells, and induced the release of neurotrophic factors. However, GA treatment influences both innate and adaptive immune compartments, and it is now recognized that antigen-presenting cells (APCs) are the initial cellular targets for GA. The anti-inflammatory (M2) APCs induced following treatment with GA are responsible for the induction of anti-inflammatory T cells that contribute to its therapeutic benefit. Here, we review studies that have shaped our current understanding of the MOA of GA.

Glatiramer acetate persists at the injection site and draining lymph nodes via electrostatically-induced aggregation

Glatiramer acetate (GA) is widely prescribed for the treatment of relapsing-remitting multiple sclerosis, however, the mechanism of action is still not fully understood. We investigated the structural properties of GA and examined alterations to the drug upon injection into the subcutaneous space. First, a variety of biophysical characterization techniques were employed to characterize GA in solution. GA was found to exist as alpha helices in solution with a hydrodynamic radius of ~3 nm in size. To simulate GA behavior at the site of injection, GA was injected into a solution of 1.5 MDa hyaluronic acid (HA). Visible aggregates were observed immediately upon injection and subsequent testing indicated aggregation was driven by electrostatic interactions between the positively-charged GA and negatively-charged HA. In vivo testing confirmed GA formed spherical particles in the nano- to micrometer size range, suggesting this mechanism contributes to persistence at the injection site and in draining lymph nodes. The aggregates were found to associate with glycosaminoglycans, suggesting an electrostatic mechanism of induced aggregation like the simulated injection. These novel observations may help explain the complex immunomodulatory mechanisms of GA and adverse injection site reactions seen in patients.

Glatiramer Acetate Enhances Myeloid-Derived Suppressor Cell Function via Recognition of Paired Ig-like Receptor B

Glatiramer acetate (GA; Copaxone) is a copolymer therapeutic that is approved by the Food and Drug Administration for the relapsing-remitting form of multiple sclerosis. Despite an unclear mechanism of action, studies have shown that GA promotes protective Th2 immunity and stimulates release of cytokines that suppress autoimmunity. In this study, we demonstrate that GA interacts with murine paired Ig-like receptor B (PIR-B) on myeloid-derived suppressor cells and suppresses the STAT1/NF-κB pathways while promoting IL-10/TGF-β cytokine release. In inflammatory bowel disease models, GA enhanced myeloid-derived suppressor cell-dependent CD4⁺ regulatory T cell generation while reducing proinflammatory cytokine secretion. Human monocyte-derived macrophages responded to GA by reducing TNF-α production and promoting CD163 expression typical of alternative maturation despite the presence of GM-CSF. Furthermore, GA competitively interacts with leukocyte Ig-like receptors B (LILRBs), the human orthologs of PIR-B. Because GA limited proinflammatory activation of myeloid cells, therapeutics that target LILRBs represent novel treatment modalities for autoimmune indications.

Astrocyte disruption of neurovascular communication is linked to cortical damage in an animal model of multiple sclerosis

To elucidate mechanisms contributing to cortical pathology in multiple sclerosis (MS), we investigated neurovascular aberrations, in particular the association of astrocytes with cortical neurons and blood vessels, in mice induced with experimental autoimmune encephalomyelitis (EAE). Blood-brain barrier (BBB) dysfunction was evident by leakage of the tracer sodium fluorescein, along with reduced expression of claudin-5 by endothelial cells and desmin by pericytes. Immunohistological and ultrastructural analyses revealed detachment of the astroglial cell bodies from the blood vessels and loss of their connections with both the blood vessels and the neuronal synapses. Furthermore, examination of individual astrocytic processes at cortical layer IV, where well-defined neuronal columns (barrels) are linked to functional properties, revealed loss of astrocytic confinement to the functional neuronal boundaries. Thus, in contrast to the highly modulated patches of astrocyte processes in naïve mice overlapping the barrel cores, in EAE-mice process distribution was uniform ignoring the barrel boundaries. These aberrations are attributed to the surrounding inflammation, indicated by T-cells presence in the cortex as well as in the subcortical white matter and the meninges. Immunomodulatory treatment with glatiramer acetate partially abrogated the neurovascular damage. These combined findings indicate that under inflammatory conditions, activated perivascular astrocytes fail in neuro-hemodynamic coupling, resulting in obstructed cross-talk between the blood vessels and the neurons. We propose that loss of cortical astrocytic regulation and fine-tuning between the blood supply and the neuronal needs contributes to the neurological impairment and cognitive decline occurring in EAE/MS as well as to the disease progression.

Impact of Glatiramer Acetate on B Cell-Mediated Pathogenesis of Multiple Sclerosis

Growing evidence indicates that B cells play a key role in the pathogenesis of multiple sclerosis (MS). B cells occupy distinct central nervous system (CNS) compartments in MS, including the cerebrospinal fluid and white matter lesions. Also, it is now known that, in addition to entering the CNS, B cells can circulate into the periphery via a functional lymphatic system. Data suggest that the role of B cells in MS mainly involves their in situ activation in demyelinating lesions, leading to altered pro- and anti-inflammatory cytokine secretion, and a highly effective antigen-presenting cell function, resulting in activation of memory or naïve T cells. Clinically, B cell-depleting agents show significant efficacy in MS. In addition, many disease-modifying therapies (DMTs) traditionally understood to target T cells are now known to influence B cell number and function. One of the earliest DMTs to be developed, glatiramer acetate (GA), has been shown to reduce the total frequency of B cells, plasmablasts, and memory B cells. It also appears to promote a shift toward reduced inflammation by increasing anti-inflammatory cytokine release and/or reducing pro-inflammatory cytokine release by B cells. In the authors' opinion, this may be mediated by cross-reactivity of B cell receptors for GA with antigen (possibly myelin basic protein) expressed in the MS lesion. More research is required to further characterize the role of B cells and their bidirectional trafficking in the pathogenesis of MS. This may uncover novel targets for MS treatments and facilitate the development of B cell biomarkers of drug response.

Effector and regulatory B cells in Multiple Sclerosis

The role of B cells in the pathogenesis of Multiple Sclerosis (MS), an autoimmune neurodegenerative disease, is becoming eminent in recent years, but the specific contribution of the distinct B cell subsets remains to be elucidated. Several B cell subsets have shown regulatory, anti-inflammatory capacities in response to stimuli in vitro, as well as in the animal model of MS: Experimental Autoimmune Encephalomyelitis (EAE). However, the functional role of the B regulatory cells (Bregs) in vivo and specifically in the human disease is yet to be clarified. In the present review, we have summarized the updated information on the roles of effector and regulatory B cells in MS and the immune-modulatory effects of MS therapeutic agents on their phenotype and function.

IL-27: a potential biomarker for responders to glatiramer acetate therapy

Glatiramer acetate (GA) is an FDA-approved efficacious drug for the treatment of relapsing-remitting multiple sclerosis (RRMS). However, this treatment is not effective for all RRMS patients. Therefore, it is important to identify reliable biomarkers that can predict a beneficial clinical response to GA therapy. Since an increase in IL-27 has been demonstrated to suppress autoimmune and allergic diseases of inflammatory origin, we examined the effect of GA on the production of IL-27. We observed that IL-27 production in PBMCs cultured with GA was heterogeneous amongst MS patients and healthy donors (HD), and thus, defined these MS patients as either efficient, weak, or non-IL-27 producers. Interestingly, GA could induce the expression of the IL-27p28 subunit more efficiently than the IL-27 EBI3 subunit, and the production of IL-27 depended on MHC class II binding by GA. In addition, we found that GA could augment Toll-like receptor (TLR)-mediated IL-27 production. Importantly, serum production of IL-27 and IL-10 was significantly increased at 6months during GA therapy in clinical responders to GA, but not in GA non-responders. Altogether, our data suggest that GA-induced IL-27 may represent a therapeutic mechanism of GA-mediated immunomodulation and that GA-mediated IL-27 production in PBMCs is worth exploring as a biomarker to screen for GA responders prior to the initiation of GA treatment.

Jessner-Kanof lymphocytic infiltration of the skin associated with glatiramer acetate

Glatiramer acetate (GLAT) is a well tolerated and safe immunomodulatory drug for the treatment of relapsing=remitting multiple sclerosis. The most commonly recognized side effects are localized injection site reactions consisting of pain, pruritus, mild erythema and induration, which sometimes persist for several days. We describe the first case of a biopsy-proven lymphocytic infiltration (T-cell pseudolymphoma) with the clinical appearance of a figured erythema on the ventrolateral thighs in the first four weeks under GLAT treatment, resolving without any evidence of recurrence despite ongoing therapy. A T-cell pseudolymphoma is a very rare side effect of GLAT treatment. For clinical purposes it is important to state that re-exposition after GLAT-induced pseudolymphoma is possible without permanent sequelae.

Multiple Sclerosis: New Approaches to Immunotherapy

Until recently, the treatment of multiple sclerosis (MS) was restricted to symptomatic therapies. Advances in our understanding of the pathogenesis of MS are now resulting in the rapid proliferation of treatment strategies to slow or stop the progression of this disease. Clearly, immunological therapies can improve outcomes in MS and offer hope that this crippling disease can be controlled before patients develop major neurological disabilities. Immunological therapies under investigation for the treatment of MS are taking advantage of dramatic improvements in our understanding of immunoregulation. In addition, immunological treatment of MS is becoming selective relative to myelin antigens, enhancing efficacy and reducing toxicity. The Neuroscientist 2:127-136, 1996

Cytokine-Defined B Cell Responses as Therapeutic Targets in Multiple Sclerosis

Important antibody-independent pathogenic roles of B cells are emerging in autoimmune diseases, including multiple sclerosis (MS). The contrasting results of different treatments targeting B cells in patients (in spite of predictions of therapeutic benefits from animal models) call for a better understanding of the multiple roles that distinct human B cell responses likely play in MS. In recent years, both murine and human B cells have been identified with distinct functional properties related to their expression of particular cytokines. These have included regulatory (Breg) B cells (secreting interleukin (IL)-10 or IL-35) and pro-inflammatory B cells (secreting tumor necrosis factor α, LTα, IL-6, and granulocyte macrophage colony-stimulating factor). Better understanding of human cytokine-defined B cell responses is necessary in both health and diseases, such as MS. Investigation of their surface phenotype, distinct functions, and the mechanisms of regulation (both cell intrinsic and cell extrinsic) may help develop effective treatments that are more selective and safe. In this review, we focus on mechanisms by which cytokine-defined B cells contribute to the peripheral immune cascades that are thought to underlie MS relapses, and the impact of B cell-directed therapies on these mechanisms.

[A place of first-line drugs in treatment of multiple sclerosis]

A rapidly changing set of drugs for treatment of multiple sclerosis (MS) leads to the necessity of searching for predictors of their efficacy. Understanding of pathogenetic processes in MS and mechanisms of action of different drugs play an important role in the search for markers of potential responders. The author analyses the presently accumulated information on the original drug copaxone (glatiramer acetate) including current concepts on the mechanism of action, long-term safety and efficacy. Data on the frequency and significance of adverse effects during treatment with glatiramer acetate as well as on the influence of the drug on pregnancy, postpartum course of MS and development of the infant who received glatiramer acetate prenatally compared to other disease-modifying drugs are presented.

Seeking balance: Potentiation and inhibition of multiple sclerosis autoimmune responses by IL-6 and IL-10

The cytokines IL-6 and IL-10 are produced by cells of the adaptive and innate arms of the immune system and they appear to play key roles in genetically diverse autoimmune diseases such as relapsing remitting multiple sclerosis (MS), rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). Whereas previous intense investigations focused on the generation of autoantibodies and their contribution to immune-mediated pathogenesis in these diseases; more recent attention has focused on the roles of cytokines such as IL-6 and IL-10. In response to pathogens, antigen presenting cells (APC), including B cells, produce IL-6 and IL-10 in order to up-or down-regulate immune cell activation and effector responses. Evidence of elevated levels of the proinflammatory cytokine IL-6 has been routinely observed during inflammatory responses and in a number of autoimmune diseases. Our recent studies suggest that MS peripheral blood B cells secrete higher quantities of IL-6 and less IL-10 than B cells from healthy controls. Persistent production of IL-6, in turn, contributes to T cell expansion and the functional hyperactivity of APC such as MS B cells. Altered B cell activity can have a profound impact on resultant T cell effector functions. Enhanced signaling through the IL-6 receptor can effectively inhibit cytolytic activity, induce T cell resistance to IL-10-mediated immunosuppression and increase skewing of autoreactive T cells to a pathogenic Th17 phenotype. Our recent findings and studies by others support a role for the indirect attenuation of B cell responses by Glatiramer acetate (GA) therapy. Our studies suggest that GA therapy temporarily permits homeostatic regulatory mechanisms to be reinstated. Future studies of mechanisms underlying dysregulated B cell cytokine production could lead to the identification of novel targets for improved immunoregulatory therapies for autoimmune diseases.

The effect of glatiramer acetate therapy on functional properties of B cells from patients with relapsing-remitting multiple sclerosis

IMPORTANCE

This study describes what is, to our knowledge, the previously unknown effect of glatiramer acetate therapy on B cells in patients with relapsing-remitting multiple sclerosis (MS).

OBJECTIVE

To determine whether glatiramer acetate therapy normalizes dysregulated B-cell proliferation and cytokine production in patients with MS.

DESIGN, SETTING, AND PARTICIPANTS

Twenty-two patients with MS who were receiving glatiramer acetate therapy and 22 treatment-naive patients with MS were recruited at The University of Texas Southwestern Medical Center MS clinic. Cell samples from healthy donors were obtained from HemaCare (Van Nuys, California) or Carter Blood Bank (Dallas, Texas). Treatment-naive patients with MS had not received any disease-modifying therapies for at least 3 months before the study.

EXPOSURES

Glatiramer acetate therapy for at least 3 months at the time of the study.

MAIN OUTCOMES AND MEASURES

B-cell phenotype and proliferation and immunoglobulin and cytokine secretion.

RESULTS

A restoration of interleukin 10 production by peripheral B cells was observed in patients undergoing glatiramer acetate therapy as well as a significant reduction of interleukin 6 production in a subset of patients who received therapy for less than 32 months. Furthermore, proliferation in response to high-dose CD40L was altered and immunoglobulin production was elevated in in vitro-activated B cells obtained from patients who received glatiramer acetate.

CONCLUSIONS AND RELEVANCE

Glatiramer acetate therapy remodels the composition of the B-cell compartment and influences cytokine secretion and immunoglobulin production. These data suggest that glatiramer acetate therapy affects several aspects of dysregulated B-cell function in MS that may contribute to the therapeutic mechanisms of glatiramer acetate.

Immunomodulation neuroprotection and remyelination - the fundamental therapeutic effects of glatiramer acetate: a critical review

Multiple sclerosis (MS) is a multifaceted heterogeneous disease with various patterns of tissue damage. In addition to inflammation and demyelination, widespread axonal and neuronal pathologies are central components of this disease. MS therapies aim to restrain the pathological processes, enhance protective mechanisms, and prevent disease progression. The amino acid copolymer, glatiramer acetate (GA, Copaxone), an approved treatment for MS, has a unique mode of action. Evidence from the animal model experimental autoimmune encephalomyelitis (EAE) and from MS patients indicates that GA affects various levels of the innate and the adaptive immune response, inducing deviation from the pro-inflammatory to the anti-inflammatory pathways. This includes competition for the binding of antigen presenting cells, driving dendritic cells, monocytes, and B-cells towards anti-inflammatory responses, induction of Th2/3 and T-regulatory cells, and downregulating of both Th1 and Th-17 cells. The immune cells induced by GA reach the inflamed disease organ and secrete in situ anti-inflammatory cytokines alleviating the pathological processes. Furthermore, cumulative findings have revealed that in addition to its immunomodulatory activities GA promotes neuroprotective repair processes such as neurotrophic factors secretion and remyelination. This review aims to provide a comprehensive overview on the diverse mechanism of action of GA in EAE/MS, in particular on the in situ effect of GA and its ability to generate neuroprotection and repair in the CNS. In view of its immunomodulatory activity, the beneficial effects of GA in various models of additional autoimmune related pathologies, such as immune rejection and inflammatory bowel disease (IBD), are also presented.

Optimizing therapeutics in the management of patients with multiple sclerosis: a review of drug efficacy, dosing, and mechanisms of action

Multiple sclerosis (MS) is a debilitating neurological disorder that affects nearly 2 million adults, mostly in the prime of their youth. An environmental trigger, such as a viral infection, is hypothesized to initiate the abnormal behavior of host immune cells: to attack and damage the myelin sheath surrounding the neurons of the central nervous system. While several other pathways and disease triggers are still being investigated, it is nonetheless clear that MS is a heterogeneous disease with multifactorial etiologies that works independently or synergistically to initiate the aberrant immune responses to myelin. Although there are still no definitive markers to diagnose the disease or to cure the disease per se, research on management of MS has improved many fold over the past decade. New disease-modifying therapeutics are poised to decrease immune inflammatory responses and consequently decelerate the progression of MS disease activity, reduce the exacerbations of MS symptoms, and stabilize the physical and mental status of individuals. In this review, we describe the mechanism of action, optimal dosing, drug administration, safety, and efficacy of the disease-modifying therapeutics that are currently approved for MS therapy. We also briefly touch upon the new drugs currently under investigation, and discuss the future of MS therapeutics.

Design of peptide immunotherapies for MHC Class-II-associated autoimmune disorders

Autoimmune disorders, that occur when autoreactive immune cells are induced to activate their responses against self-tissues, affect one percent of the world population and represent one of the top 10 leading causes of death. The major histocompatibility complex (MHC) is a principal susceptibility locus for many human autoimmune diseases, in which self-tissue antigens providing targets for pathogenic lymphocytes are bound to HLA molecules encoded by disease-associated alleles. In spite of the attempts to design strategies for inhibition of antigen presentation targeting the MHC-peptide/TCR complex via generation of blocking antibodies, altered peptide ligands (APL), or inhibitors of costimulatory molecules, potent therapies with minimal side effects have yet to be developed. Copaxone (glatiramer acetate, GA) is a random synthetic amino acid copolymer that reduces the relapse rate by about 30% in relapsing-remitting multiple sclerosis (MS) patients. Based on the elucidated binding motifs of Copaxone and of the anchor residues of the immunogenic myelin basic protein (MBP) peptide to HLA-DR molecules, novel copolymers have been designed and proved to be more effective in suppressing MS-like disease in mice. In this report, we describe the rationale for design of second-generation synthetic random copolymers as candidate drugs for a number of MHC class-II-associated autoimmune disorders.

Glatiramer acetate treatment effects on gene expression in monocytes of multiple sclerosis patients

Background

Glatiramer acetate (GA) is a mixture of synthetic peptides used in the treatment of patients with relapsing-remitting multiple sclerosis (RRMS). The aim of this study was to investigate the effects of GA therapy on the gene expression of monocytes.

Methods

Monocytes were isolated from the peripheral blood of eight RRMS patients. The blood was obtained longitudinally before the start of GA therapy as well as after one day, one week, one month and two months. Gene expression was measured at the mRNA level by microarrays.

Results

More than 400 genes were identified as up-regulated or down-regulated in the course of therapy, and we analyzed their biological functions and regulatory interactions. Many of those genes are known to regulate lymphocyte activation and proliferation, but only a subset of genes was repeatedly differentially expressed at different time points during treatment.

Conclusions

Overall, the observed gene regulatory effects of GA on monocytes were modest and not stable over time. However, our study revealed several genes that are worthy of investigation in future studies on the molecular mechanisms of GA therapy.

The pharmacokinetics of glatiramer acetate for multiple sclerosis treatment

INTRODUCTION

Multiple sclerosis (MS) is a T-cell-mediated disease affecting the central nervous system (CNS), characterized by demyelination and axonal degeneration. INF-β1b was the first drug approved for MS patients in 1993. In 1996, glatiramer acetate (GA), a synthetic copolymer, was approved in the USA for the treatment of relapsing-remitting MS (RRMS) and clinically isolated syndrome (CIS). Although the immunological action of GA has been fully investigated, the exact mechanisms of action of GA are still not completely elucidated. Several in vitro studies on mice and human antigen-presenting cells (APCs) have shown that GA is able to bind to the major histocompatibility complex (MHC), on the surface of APCs, recognizing myelin basic protein (MBP).

AREAS COVERED

This review explores the pharmacological characteristics of GA, its mechanism of action and its pharmacokinetics properties. The article also provides information on the efficacy, tolerability and an overview of the most important clinical data on GA.

EXPERT OPINION

Despite the development of novel compounds, it is not surprising that GA is, to date, one of the most prescribed drugs for RRMS patients and CIS patients. The proven efficacy and the mild adverse events, makes GA a good therapeutic option in the early stage of the disease. This is particularly useful for patients who suffer flu-like symptoms from other RRMS therapies as an alternative.

A naturally processed HLA-DR-bound peptide from the IL-9 receptor alpha of HTLV-1-transformed T cells serves as a T helper epitope

Human T cell leukemia virus type 1 (HTLV-1) induced adult T cell leukemia/lymphoma (ATLL) is usually a fatal lymphoproliferative malignant disease. Thus, the enhancement of T cell immunity to ATLL through the development of therapeutic vaccines using characterized T cell peptide epitopes could be of value. We isolated and characterized HLA-DR-bound peptides from HTLV-1-transformed T cells by fractionating on reverse-phase high performance liquid chromatography and Edman NH(2)-terminal sequencing and were able to identify five independent peptide sequences. One of the identified peptide sequences corresponded to a fragment of the human interleukin-9 receptor alpha (IL-9Rα), which is commonly expressed by HTLV-1-infected T cell lymphoma cells. Using a synthetic peptide corresponding to the identified IL-9Rα sequence, we generated antigen-specific CD4 helper T lymphocytes in vitro, which were restricted by HLA-DR15 or HLA-DR53 molecules and could recognize and kill HTLV-1+, IL-9Rα+ T cell lymphoma cells. These results indicate that IL-9Rα functions as T cell leukemia/lymphoma-associated antigen for CD4 T cells and that synthetic peptides such as the one described here could be used for T cell-based immunotherapy against IL-9Rα positive ATLL.

The mechanism of action of glatiramer acetate in multiple sclerosis and beyond

In multiple sclerosis (MS) and its animal model experimental autoimmune encephalomyelitis (EAE), the immune system reacts again self myelin constitutes in the central nervous system (CNS), initiating a detrimental inflammatory cascade that leads to demyelination as well as axonal and neuronal pathology. The amino acid copolymer glatiramer acetate (GA, Copaxone) is an approved first-line treatment for MS that has a unique mode of action. Accumulated evidence from EAE-induced animals and from MS patients indicates that GA affects various levels of the innate and the adaptive immune response, generating deviation from the pro-inflammatory to the anti-inflammatory pathway. This review aims to provide a comprehensive perspective on the diverse mechanism of action of GA in EAE/MS, in particular on the in situ immunomodulatory effect of GA and its ability to generate neuroprotective repair consequences in the CNS. In view of its immunomodulatory activity, the beneficial effect of GA in various models of other autoimmune related pathologies, such as immune rejection and inflammatory bowel disease (IBD) is noteworthy.

The role of dendritic cells in the generation of CD4(+) CD25(HI) Foxp3(+) T cells induced by amino acid copolymers

The effects of the amino acid copolymers used in the therapy of experimental autoimmune encephalomyelitis, poly(Y,E,A,K)(n) (Copaxone(®)) and poly(Y,F,A,K)(n), on murine myeloid cells have been investigated. After administration of these copolymers to mice, increases in several splenic myeloid cell populations were observed, including CD11b(+) CD11c(+) dendritic cells. The latter were the major splenic cell type that secreted CCL22 (macrophage-derived chemokine) on stimulation with amino acid copolymers. CCL22 secretion was also stimulated from bone marrow-derived dendritic cells (BMDC) generated with GM-CSF in much larger amounts than from bone marrow-derived macrophages generated with M-CSF. Moreover, CCL22 secretion could also be obtained using BMDC generated from two different types of MHC II(-/-) mice, indicating that an innate immune receptor is involved. Finally, incubation of these BMDC or splenic dendritic cells with naive CD4(+) CD25(-) T cells resulted in formation of CD4(+) CD25(HI) Foxp3 T cells (~25% of which were Foxp3(+)). The number of these regulatory cells was doubled by pretreatment of BMDC with amino acid copolymers.

Clinical utility of glatiramer acetate in the management of relapse frequency in multiple sclerosis

Glatiramer acetate (GA) represents one of the most common disease-modifying therapies for multiple sclerosis. GA is currently approved for patients at high risk of developing clinically definite multiple sclerosis (CDMS) after having experienced a well-defined first clinical episode (clinically isolated syndrome or CIS) and for patients with relapsing-remitting multiple sclerosis (RRMS). GA’s efficacy and effectiveness to reduce relapse frequency have been proved in placebo-controlled and observational studies. Comparative trials have also confirmed the lack of significant differences over other choices of treatment in the management of relapse frequency, and long-term studies have supported its effect at extended periods of time. Additionally, RRMS patients with suboptimal response to interferon β may benefit from reduced relapse rate after switching to GA, and those with clinically isolated syndrome may benefit from delayed conversion to CDMS. All these results, together with its proven long-term safety and positive effect on patients’ daily living, support the favorable risk-benefit of GA for multiple sclerosis treatment.

Macrophage-specific chemokines induced via innate immunity by amino acid copolymers and their role in EAE

The random amino acid copolymer poly(Y,E,A,K)_n (Copaxone®) is widely used in multiple sclerosis treatment and a second generation copolymer poly(Y,F,A,K)_n with enhanced efficacy in experimental autoimmune encephalomyelitis in mice has been described. A major mechanism through which copolymers function to ameliorate disease is the generation of immunosuppressive IL-10-secreting regulatory T cells entering the CNS. In addition, the antigen presenting cell to which these copolymers bind through MHC Class II proteins may have an important role. Here, both CCL22 (a Th2 cell chemoattractant) in large amounts and CXCL13 in much smaller amounts are shown to be secreted after administration of YFAK to mice and to a smaller extent by YEAK parallel to their serum concentrations. Moreover, bone marrow-derived macrophages secrete CCL22 in vitro in response to YFAK and to higher concentrations of YEAK. Strikingly, these chemokines are also secreted into serum of MHC Class II −/− mice, indicating that an innate immune receptor on these cells also has an important role. Thus, both the innate and the adaptive immune systems are involved in the mechanism of EAE amelioration by YFAK. The enhanced ability of YFAK to stimulate the innate immune system may account for its enhanced efficacy in EAE treatment.

Allelic combinations of immune-response genes associated with glatiramer acetate treatment response in Russian multiple sclerosis patients

BACKGROUND

Glatiramer acetate (GA) is widely used as a first-line disease-modifying treatment for multiple sclerosis (MS). However, a significant proportion of MS patient appears to experience modest benefit from GA-treatment. Genetic variants affecting the clinical response to GA are believed to be relevant as biomarkers of GA-treatment efficiency.

PATIENTS & METHODS

Nine polymorphisms in candidate genes were analyzed as possible determinants of GA response in 285 Russian MS patients. Special attention was given to identification of response-associated allelic combinations by means of the APSampler algorithm.

RESULTS

No significant associations were found for individual polymorphisms. Alleles DRB1*15, TGFB1*T, CCR5*d and IFNAR1*G were the components of the combinations, of which carriage was significantly higher in nonresponders than in responders. Carriers of the most significant combinations: DRB1*15 + TGFB1*T + CCR5*d + IFNAR1*G and DRB1*15 + TGFB1*T + CCR5*d (permutation p-values: 0.0056 and 0.013, respectively) had a 14 to 15-times increased risk of ineffective response to GA therapy.

DISCUSSION

The results suggest that the influence of immune-response genes on GA-induced response has a polygenic nature. The data are interpreted as evidence of additive and epistatic influences of the genes on GA efficiency for MS treatment.

Distinct pathological patterns in relapsing-remitting and chronic models of experimental autoimmune enchephalomyelitis and the neuroprotective effect of glatiramer acetate

The respective roles of inflammatory and neurodegenerative processes in the pathology of multiple sclerosis (MS) and in its animal model experimental autoimmune encephalomyelitis (EAE) are controversial. Novel treatment strategies aim to operate within the CNS to induce neuroprotection and repair processes in addition to their anti-inflammatory properties. In this study we analyzed and compared the in situ pathological manifestations of EAE utilizing two different models, namely the relapsing-remitting PLP-induced and the chronic MOG-induced diseases. To characterize pathological changes, both transmission electron microscopy (TEM) and immunohistochemistry were employed. The effect of the approved MS drug glatiramer acetate (GA, Copaxone) on myelin damage/repair and on motor neuron loss/preservation was studied in both EAE models. Ultrastructural spinal cord analysis revealed multiple white matter damage foci, with different patterns in the two EAE models. Thus, the relapsing-remitting model was characterized mainly by widespread myelin damage and by remyelinating fibers, whereas in the chronic model axonal degeneration was more prevalent. Loss of lower motor neurons was manifested only in mice with chronic MOG-induced disease. In the GA-treated mice, smaller lesions, increased axonal density and higher prevalence of normal appearing axons were observed, as well as decreased demyelination and degeneration. Furthermore, quantitative analysis of the relative remyelination versus demyelination, provides for the first time evidence of significant augmentation of remyelination after GA treatment. The loss of motor neurons in GA-treated mice was also reduced in comparison to that of EAE untreated mice. These effects were obtained even when GA treatment was applied in a therapeutic schedule, namely after the appearance of clinical symptoms. Hence, the remyelination and neuronal preservation induced by GA are in support of the neuroprotective consequences of this treatment.