Suppression of experimental allergic encephalomyelitis by a synthetic polypeptide

Immunomodulation of experimental autoimmune encephalomyelitis by oral administration of copolymer 1

The activity of copolymer 1 (Cop 1, Copaxone, glatiramer acetate) in suppressing experimental autoimmune encephalomyelitis (EAE) and in the treatment of multiple sclerosis patients when injected parenterally has been extensively demonstrated. In the present study we addressed the question of whether Cop 1 can induce oral tolerance to EAE similar to myelin basic protein (MBP). We now have demonstrated that oral Cop 1 inhibited EAE induction in both rats and mice. Furthermore, oral Cop 1 was more effective than oral MBP in suppressing EAE in rats. The beneficial effect of oral Cop 1 was found to be associated with specific inhibition of the proliferative and Th1 cytokine secretion responses to MBP of spleen cells from Cop 1-fed mice and rats. In all of these assays, oral Cop 1 was more effective than oral MBP. The tolerance induced by Cop 1 could be adoptively transferred with spleen cells from Cop 1-fed animals. Furthermore, Cop 1-specific T cell lines, which inhibit EAE induction in vivo, could be isolated from the above spleen cells. These T cell lines secrete the anti-inflammatory cytokines IL-10 and transforming growth factor type beta, but not IL-4, in response to both Cop 1 and MBP. In conclusion, oral Cop 1 has a beneficial effect on the development of EAE that is associated with down-regulation of T cell immune responses to MBP and is mediated by Th2/3 type regulatory cells. These results suggest that oral administration of Cop 1 may modulate multiple sclerosis as well.

Herpesviruses--a rationale for antiviral treatment in multiple sclerosis

In multiple sclerosis (MS), the extensive and long lasting search for viruses or other pathogens has hitherto failed to identify a common etiological agent. However, the beneficial effects by interferon-beta treatment in MS, although suggested to depend mainly on immunomodulation, might lend support to a viral involvement in the pathogenesis. The human herpesviruses have attracted interest since their recurrent modes of infection share some similarity with the relapsing-remitting course of MS, most members are readily detected within the brain, and several of these viruses may induce demyelination within the central nervous system in human hosts as well as in animal models. Accumulated diagnostic and epidemiological data are compatible with a role for the herpesviruses as possible cofactors rather than etiological agents, and recent studies showing early neuronal damage in MS patients focus attention on the neurotropic alpha-herpesviruses. Antiviral treatment trials with safe and effective drugs such as valaciclovir offer a possibility of testing the hypotheses concerning herpesviral involvement in MS.

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.

Synthetic amino acid copolymers that bind to HLA-DR proteins and inhibit type II collagen-reactive T cell clones

Copolymer 1 [poly(Y,E,A,K)] is a random synthetic amino acid copolymer of L-tyrosine, L-glutamic acid, L-alanine, and L-lysine that is effective both in suppression of experimental allergic encephalomyelitis and in the treatment of relapsing forms of multiple sclerosis. Copolymer 1 binds promiscuously and very efficiently to purified HLA-DR molecules within the peptide-binding groove. In the present study, YEAK and YEAK-related copolymers and type II collagen (CII) peptide 261-273, a candidate autoantigen in rheumatoid arthritis (RA), competed for binding to RA-associated HLA-DR molecules encoded by DRB1*0101 and DRB1*0401. Moreover, these copolymers (particularly YEAK, YAK, and YEK) inhibited the response of DR1- and DR4-restricted T cell clones to the CII epitope 261-273 by >50%. This direct evidence both for competitive interactions of these copolymers and CII peptide with RA-associated HLA-DR molecules and for inhibition of CII-specific T cell responses suggests that these compounds should be evaluated in animal models for rheumatoid arthritis.

Promiscuous Binding of Synthetic Copolymer 1 to Purified HLA-DR Molecules

Copolymer 1 (Cop 1) is a random synthetic amino acid copolymer of l-alanine, l-glutamic acid, l-lysine, and l-tyrosine, effective both in suppression of experimental allergic encephalomyelitis and in the treatment of relapsing forms of multiple sclerosis. Cop 1 binds promiscuously and very efficiently to living APCs of various HLA haplotypes. In the present study, a substantial part of the whole mixture of random polypeptides that compose Cop 1 was shown to bind to purified human HLA-DR1, DR2, and DR4 with high affinity in a temperature- and time (and, in the case of DR4, pH)-dependent manner, and was competitively inhibited by DR-restricted peptides, but not by peptide derivatives that bind with low affinity. Bacterial superantigens inhibited Cop 1 binding only at very high concentrations. The formation of the Cop 1-DR1 complex was also shown by SDS-PAGE. These findings represent the first direct evidence for interactions of Cop 1 with purified DR molecules, and suggest that its effectiveness in experimental allergic encephalomyelitis and multiple sclerosis may be directly related to its binding in the groove of HLA-DR proteins.

Glatiramer acetate blocks the activation of THP-1 cells by interferon-gamma

Glatiramer acetate (previously known as copolymer 1) is a synthetic copolymer of four amino acids that has been approved for use in the treatment of multiple sclerosis. It has been shown to suppress myelin antigen specific T cell activation by competing with these antigens at the major histocompatibility complex class II binding site and by inducing antigen specific suppressor T cells. In this study we investigated the effects of glatiramer acetate on the human monocytic cell line, THP-1, activated by lipopolysaccharide and interferon-gamma as a model for macrophages. At non-toxic concentrations of glatiramer acetate there were dose dependent reductions in the percentage of cells expressing human leukocyte DR and DQ antigen as well as in mean fluorescence intensity by flow cytometry. Production of tumor necrosis factor-alpha and the lysosomal cysteine proteinase cathepsin B were markedly inhibited, but production of interleukin-1 increased. These results suggest that glatiramer acetate might alter macrophage effector function and suggest that further studies in human monocytes and macrophages are warranted.

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.

Studies on the mechanism and specificity of the effect of the synthetic random copolymer GLAT on graft-versus-host disease

Graft-versus-host disease (GVHD), which occurs when donor T-cells recognize multiple minor host histocompatibility antigens as non-self, presents the major limitation to successful allogeneic bone-marrow transplantation. The synthetic random copolymer of the amino acids, L-Glu, L-Lys, L-Ala and L-Tyr, termed GLAT, with promiscuous binding to multiple MHC class II alleles, reduces the incidence, onset and severity of disease in the BIO.D2 --> BALB/c model of lethal GVHD. GLAT inhibited the proliferative response towards host of both spleen cells from mice with GVHD and also of the effector T cell line established from these mice. Administration of GLAT for a limited period after transplantation completely abolished the cytotoxic activity toward host cells exerted by spleen cells from mice with GVHD. Whereas spleen and bone marrow cells from control mice with GVHD secreted IL-2 and INF-gamma when cocultured with host cells, these inflammatory cytokines could not be detected in supernatants of cells from GLAT treated mice. Moreover spleens and bone marrow cells from GLAT treated mice secreted small but significant amounts of IL-4 and IL-6 when cocultured with GLAT, suggesting that GLAT not only inhibits pro-GVHD cytokines but also causes a beneficial effect by inducing secretion of Th2 type cytokines. GLAT binds strongly to MHC molecules of host as well as donor haplotype. D-GLAT, identical to GLAT but composed of D-amino acids is also effective in preventing GVHD. D-GLAT does not cross-react with L-GLAT, but still binds strongly to MHC-class II molecules. These findings indicate that MHC blocking is involved in the therapeutic effect of GLAT on GVHD. The cumulative data demonstrate that GLAT modulates the effector mechanisms involved in GVHD, and can be potentially used for the prevention of GVHD across minor histocompatibility barriers.

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.

Investigational drug therapies of treatment of multiple sclerosis

The licensing of interferon beta-1b dramatically changed the treatment of multiple sclerosis (MS) in the United States. Although it was the first therapeutic agent shown to affect the natural course of the disease, interferon beta-1b is not appropriate for all patients and is far from being a cure. Several other promising therapies now under study include immunosuppressive and immunomodulatory drugs to limit inflammation; oral administration of myelin to induce tolerance; monoclonal antibodies designed to deliver targeted immunotherapy; potassium channel blockers to facilitate conduction along demyelinated axons; and glial growth factors to promote remyelination. Clinical trials of potential therapeutic agents have proliferated in the past decade in conjunction with rapid advances in our understanding of the immunologic basis of MS. Some investigational therapies are associated with problematic toxicities, others benefit only a minority of patients, and many are still in the early stages of development. Nevertheless, because current therapeutic options are limited, and because the history of MS therapy is one of disappointment and frustration, it is essential that legitimate, scientifically based advances be widely disseminated to the neurologic community. This article reviews some of the most promising current and investigational therapies for MS.

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.

Interferon-gamma in autoimmunity

Autoimmune disorders are characterized by abrogation of self-tolerance, resulting in emergence of activated self-reactive lymphocyte clones that trigger or maintain inflammatory reactions in specific organs. Interferon-gamma (IFN-gamma), as well as other cytokines, plays an important role as a regulator of the activation of self-reactive lymphocytes and of bystander and accessory cells that are involved in the autoimmune inflammatory response. In experimental models of autoimmunity, endogenous IFN-gamma has invariably been found to profoundly affect the disease course. However, it acts in one way in some diseases and in the opposite way in others.

A synthetic random basic copolymer with promiscuous binding to class II major histocompatibility complex molecules inhibits T-cell proliferative responses to major and minor histocompatibility antigens in vitro and confers the capacity to prevent murine graft-versus-host disease in vivo

Graft-versus-host disease (GVHD) is a T-cell-mediated disease of transplanted donor T cells recognizing host alloantigens. Data presented in this report show, to our knowledge, for the first time that a synthetic copolymer of the amino acids L-Glu, L-Lys, L-Ala, and L-Tyr (molecular ratio, 1.9:6.0:4.7:1.0; Mr, 6000-8500) [corrected], termed GLAT, with promiscuous binding to multiple major histocompatibility complex class II alleles is capable of preventing lethal GVHD in the B10.D2 --> BALB/c model (both H-2d) across minor histocompatibility barriers. Administration of GLAT over a limited time after transplant significantly reduced the incidence, onset, and severity of disease. GLAT also improved long-term survival from lethal GVHD: 14/25 (56%) of experimental mice survived > 140 days after transplant compared to 2/26 of saline-treated or to 1/10 of hen egg lysozyme-treated control mice (P < 0.01). Long-term survivors were documented to be fully chimeric by PCR analysis of a polymorphic microsatellite region in the interleukin 1beta gene. In vitro, GLAT inhibited the mixed lymphocyte culture in a dose-dependent fashion across a variety of major barriers tested. Furthermore, GLAT inhibited the response of nylon wool-enriched T cells to syngeneic antigen-presenting cells presenting minor histocompatibility antigens. Prepulsing of the antigen-presenting cells with GLAT reduced the proliferative response, suggesting that GLAT inhibits antigen presentation.

The autoimmune reactivity to myelin oligodendrocyte glycoprotein (MOG) in multiple sclerosis is potentially pathogenic: effect of copolymer 1 on MOG-induced disease

Multiple sclerosis (MS), an autoimmune disease of the central nervous system (CNS) characterized by primary demyelination, is believed to result from an autoimmune attack against myelin components. In view of their ability to induce experimental autoimmune encephalomyelitis (EAE), an animal model for MS, the quantitatively major malign proteins--myelin basic protein (MBP) and proteolipid protein (PLP)--have been extensively studied as the relevant primary antigens in MS, and therapeutic approaches have been targeted to counteract autoimmune reactivity to MBP and PLP. Accordingly, copolymer 1, a random synthetic amino acid copolymer crossreactive with MBP and highly protective against the induction of EAE with MBP or PLP, is not being extensively tested in clinical studies as a therapeutic agent for MS. However, increasing evidence suggests that autoimmune reactivity against other CNS-specific myelin proteins could also be involved in the pathogenesis of MS. In this context, we have demonstrated that peripheral blood lymphocytes from patients with MS respond predominantly to myelin oligodendrocyte glycoprotein (MOG) rather than to MBP or PLP, suggesting an important role for cell reactivity against MOG in the pathogenesis of MS. We have demonstrated that T-cell reactivity in MOG can also be pathogenic by inducing neurological disease in H-2u and H-2b mice with the same peptide of MOG, pMOG 35-55. Most interestingly, the expression of the disease differed with the different MHC backgrounds. Induction of a differentially expressed disease in different strains of mice with the same myelin antigen makes this new model particularly relevant to MS, where different expression of the disease is seen in different patients. Therefore, notwithstanding the importance of the autoimmune reactivity to MBP and PLP in MS, the potentially pathogenic autoimmune reactivity to MOG must now also be taken into consideration in therapeutic approaches to MS. In this context, we have investigated the possible effect of copolymer 1 treatment on autoimmune reactivity to MOG and on the development of EAE induced by MOG. Copolymer 1 was found to inhibit the binding of MOG peptides to MHC molecules, as well as the proliferation of MOG-reactive T cells, in a dose-dependent manner. In parallel, injection of copolymer 1 concomitantly with the encephalitogenic MOG peptide exerted a strong protective effect against the development of EAE. These preliminary data on the effect of copolymer 1 on the autoimmune response to MOG in mice indicate that copolymer 1 may also be effective in cases of MS where the autoimmune response to MOG prevails, and should therefore be further investigated in this context.

New insights into the mechanism of action of copolymer 1 in experimental allergic encephalomyelitis and multiple sclerosis

Copolymer 1 is a synthetic amino acid copolymer, effective in suppression of experimental allergic encephalomyelitis (EAE) induced in a variety of species. Copolymer 1 can suppress both acute and chronic relapsing EAE induced by either whole brain homogenate or the purified encephalitogens myelin basic protein (MBP) and proteolipid protein (PLP). Thus, the suppressive effect of copolymer 1 in EAE is a general phenomenon and is not restricted to a certain species, the disease type, or the encephalitogen used for EAE induction. The suppressive activity of copolymer 1 is, however, limited to EAE, and copolymer 1 has no nonspecific immunological activity. On the other hand, a marked degree of immunological cross-reactivity in both the cellular and humoral immune responses was demonstrated between MBP and copolymer 1. This cross-reactivity may be the underlying mechanism for the specific suppressive effect of copolymer 1 in EAE. In vivo and in vitro studies using both murine and human cell cultures suggest that the mechanism for copolymer 1 activity in EAE and multiple sclerosis involves, as an initial step, the binding of copolymer 1 to the major histocompatibility complex class II molecules on antigen-presenting cells. Following this step, two pathways may be activated: (1) induction of antigen-specific suppressor T cells by determinants shared between MBP and copolymer 1, or (2) competition with MBP and other myelin-associated antigens, PLP and myelin oligodendrocyte glycoprotein, for the activation of effector T cells. These two mechanisms can act either separately or in concert to interfere in the autoimmune processes that lead to the neurological damage in EAE and multiple sclerosis.

Copolymer 1 inhibits chronic relapsing experimental allergic encephalomyelitis induced by proteolipid protein (PLP) peptides in mice and interferes with PLP-specific T cell responses

Copolymer 1 (Cop 1) is a synthetic amino acid copolymer effective in suppression of experimental allergic encephalomyelitis (EAE) and developed as a candidate drug for multiple sclerosis (MS). In the present study, we induced chronic relapsing (CR)-EAE in (SJL/J X BALB/c)F1 mice by either whole spinal cord homogenate or two synthetic peptides of proteolipid protein (PLP), p139-151 and p178-191. When Cop 1 was added to the encephalitogenic inoculum, mice were almost completely resistant to disease induction. T cell lines to p139-151 and p178-191 were specific to these peptides. Their antigen-specific responses were inhibited by Cop 1 in a dose-dependent manner, while their polyclonal response to the superantigen staphylococcal enterotoxin A (SEA) was not affected by Cop 1. Using biotinylated PLP derivatives, we demonstrated that the two PLP peptides bound to I-A(s) molecules, and that their binding was completely inhibited by unlabelled Cop 1. Furthermore, Cop 1 could displace the PLP peptides from the MHC binding site. These results support the potential of Cop 1 as a broad-spectrum drug for MS.

Random copolymers containing specific ratios of negatively charged and aromatic amino acids bind V3 disulfide loop and neutralize diverse HIV type 1 isolates

Random copolymers of polyamino acids containing negatively charged and aromatic residues at specific ratios appear to bind HIV type 1 V3 loop and neutralize diverse laboratory isolates. At least the putative heparin binding domain and isoleucine residues in the amino half of V3 are involved in the interactions with these polymers. There are a number of interesting features common between these polymer's modes of binding to the V3 and the protease inhibition drug ABT-538.

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

Copolymer 1 (Cop 1) is a synthetic basic random copolymer of amino acids that has been shown to be effective in suppression of experimental allergic encephalomyelitis and is being tested as a candidate drug for multiple sclerosis. It has been previously demonstrated that Cop 1 is immunologically cross-reactive with the autoantigen myelin basic protein (BP) and competitively inhibits the response to BP of T-cell lines and clones of different major histocompatibility complex (MHC) restrictions, of both mouse and human origin. In the present study we demonstrated the direct binding of Cop 1, using its biotinylated derivative, to MHC molecules on living antigen-presenting cells. Binding of biotinylated BP and peptide p84-102 (an immunodominant epitope of BP) was also demonstrated. Cop 1 and BP bound in a promiscuous manner to different types of antigen-presenting cells of various H-2 and HLA haplotypes. The specificity of the binding was confirmed by its inhibition with either the relevant anti-MHC class II antibodies or unlabeled analogs. Cop 1 exhibited the most extensive and fast binding to antigen-presenting cells. In addition, Cop 1 inhibited the binding of biotinylated derivatives of BP and of p84-102 to the MHC class II molecules and even displaced these antigens when already bound. Thus, these results suggest that Cop 1 indeed competes with BP for MHC binding and, thereby, inhibits T-cell responses to BP. The binding of Cop 1 to different DR alleles, probably because of its multiple MHC binding motifs, may indicate its potential as a broad-spectrum drug for multiple sclerosis.

T suppressor hybridomas and interleukin-2-dependent lines induced by copolymer 1 or by spinal cord homogenate down-regulate experimental allergic encephalomyelitis

Suppressor T (Ts) hybridomas and interleukin-2-dependent T cell lines were established from spleens of mice, which had been rendered unresponsive to experimental allergic encephalomyelitis (EAE) either by mouse spinal cord homogenate or by the synthetic suppressant copolymer 1 (Cop 1). The Ts hybridoma supernatants and the Ts line cells specifically suppressed the in vitro response to the encephalitogenic myelin basic protein (BP), as indicated by inhibition of both the proliferation and interleukin-2-secretion responses of a BP-specific T cell line. Moreover, these Ts cells prevented the development of actively induced EAE in vivo. All hybridomas and lines were most effective when injected at the time of disease induction, thus suggesting that they operate as effector suppressor cells, and functionally inhibit encephalitogenic responses. The data presented here suggest that the suppressor cells are stimulated by the protective epitopes included in the BP as well as in the Cop 1 molecules and that they play an active role in the regulation of EAE. The generation of Ts lines and hybridomas, which have been induced by Cop 1, establish the specific stimulation of suppressor cells to EAE as a mechanism underlying the therapeutic activity of Cop 1.

Copolymer-1-induced inhibition of antigen-specific T cell activation: interference with antigen presentation

Copolymer-1 (Cop-1) has been shown to inhibit in vivo development of experimental allergic encephalomyelitis (EAE) in animals and has been reported to have some therapeutic benefit in relapsing/remitting multiple sclerosis (MS). The mechanism by which Cop-1 acts in vivo is not known. The present study demonstrates that Cop-1 inhibits the in vitro response of several antigen-specific murine T cell hybridomas restricted to I-A, and to a lesser extent, I-E. The ability of human myelin basic protein (MBP)-specific T cell lines (TCL) to lyse targets in the context of three HLA-DR types associated with MS was also impaired by Cop-1. The results suggest that the observed inhibition was due to competition between Cop-1 and nominal antigen for the class II major histocompatibility complex (MHC) peptide binding site.

Synthetic copolymer 1 inhibits human T-cell lines specific for myelin basic protein

Copolymer 1 (Cop 1) is a synthetic basic random copolymer of amino acids that has been shown to be effective in suppression of experimental allergic encephalomyelitis and has been proposed as a candidate drug for multiple sclerosis. Cop 1 is immunologically cross reactive with myelin basic protein (BP) and was shown to inhibit murine BP-specific T-cell lines of various H-2 restrictions. In the present study these findings were extended to include human T-cell lines. Cop 1 competitively inhibited the proliferative responses and interleukin 2 secretion of six BP-specific T-cell lines and 13 clones with several DR restrictions and epitope specificities. Conversely, BP inhibited--albeit to a lesser extent--the response of all the Cop 1-specific T-cell lines and clones, irrespective of their DR restrictions. Another random copolymer of tyrosine, glutamic acid, and alanine, denoted TGA, had no effect on these lines. Neither Cop 1 nor BP inhibited the response of lines and clones specific for purified protein derivative. Cop 1 and BP exerted their cross-inhibitory effects only in the presence of antigen-presenting cells. These results suggest that Cop 1 can compete with BP for the binding to human major histocompatibility complex molecules. In view of recent studies implicating BP reactivity in multiple sclerosis, these findings suggest a possible mechanism for the beneficial effect of Cop 1 in this disease.

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

Antibody cross-reactivity is here demonstrated between basic protein (BP), the encephalitogenic molecule of myelin, and copolymer 1 (Cop 1), the synthetic amino acid copolymer, which has a suppressive effect on experimental allergic encephalomyelitis and is effective in reducing the number of relapses in exacerbating-remitting multiple sclerosis. This cross-reactivity is conclusively established using mouse monoclonal antibodies (mAbs). About a third of anti-rat BP mAbs and most of anti-mouse BP mAbs cross-reacted with Cop 1. This cross-reactivity could be demonstrated with anti-BP mAbs of different specificities. In addition, several anti-Cop 1 hybridomas cross-reacted with BP. This cross-reactivity was verified in several assay systems, including competitive inhibition experiments. Moreover, some anti-BP mAbs and anti-Cop 1 mAbs reacted in a heteroclitic manner and favored the cross-reactive antigen over the immunogen. In contrast to the mAbs, no cross-reactivity could be demonstrated with the antisera of immunized mice. This observation may reflect the different B-cell populations expressed in the mAb response as compared to the polyclonal response. Thus, the use of mAbs has uncovered specificities that are not evident in antisera and has revealed pronounced cross-reactivity between BP and Cop 1 at the B-cell level. These results further establish the immunological interrelationships between Cop 1 and BP, demonstrated earlier at the T-cell level.

Changes of experimental allergic encephalomyelitis by methionine-enkephalin injected into lateral ventricles of the rat brain

Our previous investigations have shown that the opioid peptide methionine-enkephalin (Met-Enk) modulates in vivo a variety of humoral and cell-mediated immune performances. In this study, rats bearing polyethylene cannulae permanently inserted into the lateral ventricles of the brain were used. Experimental allergic encephalomyelitis (EAE) was induced with guinea pig spinal cord in complete Freund's adjuvant injected into the left hind foot pad. The following groups of cannulated rats were tested: nontreated with Met-Enk or saline, intracerebroventricularly (i.c.v.) injected with saline, and i.c.v. treated with low (1 microgram/kg) dose of Met-Enk and high (1 mg/kg) dose of Met-Enk. Intact noncannulated rats sensitized for EAE served as an additional control. The results showed that i.c.v. treatment with 1 microgram/kg of Met-Enk significantly increased the incidence and severity of EAE. In contrast, injections of 1 mg/kg of Met-Enk produced a moderate decline of clinical EAE, but marked diminution of inflammatory lesions in the brain. Interestingly, histopathology of EAE was more pronounced in control rats treated i.c.v. with saline. On the other hand, control cannulated rats noninjected with saline exhibited a striking decrease of neurological and histopathological signs of the disease, thus indicating a suppressive effect of stress (surgical procedure) on EAE. In conclusion, the present study showing the central effect of Met-Enk on EAE when peptide was applied in the cerebral cavity, and earlier studies which revealed the peripheral effect on EAE when Met-Enk was administered intraperitoneally, suggests that Met-Enk exerts its immunomodulatory action both centrally and peripherally.

Treatment of adjuvant arthritis in rats: vaccination potential of a synthetic nonapeptide from the 65 kDa heat shock protein of mycobacteria

Adjuvant arthritis induced by mycobacteria in rats is a widely used model of chronic arthritis. A previously described nonapeptide (Thr-Phe-Gly-Leu-Gln-Leu-Glu-Leu-Thr, amino acid sequence 180-188) from the recombinant 65 kDa heat shock protein of Mycobacterium bovis BCG, which was found to contain a T-cell epitope recognized by both arthritogenic and protective T-cell clones in vitro, has been investigated for its vaccination and therapeutic potential in adjuvant arthritis in rats. The nonapeptide was found not to be arthritogenic, although the T cells from nonapeptide immunized rats cross-react in vitro with mycobacterial antigens. Intraperitoneal administration of 0.1 mg nonapeptide in oil at day -20 or days -2, -1 and 0, resulted in a marked reduction of incidence and severity of adjuvant arthritis. The disease process and severity were also influenced by therapeutic treatment with 0.1 mg nonapeptide injected intraperitoneally at days 7 to 10. Interestingly, subplantar or intravenous application of the nonapeptide had no influence on the disease process. Deletion of the N-terminal threonine led to complete loss of in vivo activity of the nonapeptide.

In vivo monoclonal antibody treatment with Ox19 (anti-rat CD5) causes disease relapse and terminates P2-induced immunospecific tolerance in experimental allergic neuritis

The role of CD5+ lymphocytes in the recovery phase and on immunospecific protection against experimental allergic neuritis (EAN) was examined in Lewis rats by in vivo treatment with Ox19, a mouse anti-rat CD5 monoclonal antibody. Animals pretreated with the peripheral nerve basic protein P2 and thereby rendered resistant to the disease showed clinical signs of EAN after intraperitoneal (i.p.) Ox19 injection given at the same time as the rechallenge with neuritogenic doses of myelin in Freund's complete adjuvant. Non-pretreated rats recovered from signs of EAN developed a clinical relapse after i.p. Ox19 injections. Taken together, these data suggest an important regulatory role of the CD5 receptor in the immune response.

Specific inhibition of the T-cell response to myelin basic protein by the synthetic copolymer Cop 1

Cop 1 is a synthetic basic random copolymer of L-alanine, L-glutamic acid, L-lysine, and L-tyrosine in a residue molar ratio of 6.0:1.9:4.7:1.0 and with a molecular weight of 21,000 which proved to be effective in specific suppression of experimental allergic encephalomyelitis and has been proposed as a candidate drug against multiple sclerosis. In the present study we further investigated the mechanism of Cop 1 suppressive activity and tested whether Cop 1 could inhibit the specific T-cell response to myelin basic protein (BP). Eight BP-specific T-cell lines and clones with various H-2 restrictions and antigenic specificities were used. The responses of all these lines and clones to BP, as followed by both cell proliferation and interleukin 2 secretion assays, were affected by Cop 1. For one line, a direct cross proliferation with Cop 1 was observed, whereas in the other seven lines and clones, Cop 1 specifically inhibited the responses to BP in a competitive dose-dependent manner. The inhibition of the response to BP is specific to Cop 1, as D-Cop 1 and another random acidic polymer, poly(Tyr,Glu,Ala) (TGA), both of which were previously demonstrated to be ineffective in suppression of experimental allergic encephalomyelitis, did not inhibit the response to BP. Furthermore, Cop 1 specifically inhibited only the response of the T-cell lines and clones to BP. It did not inhibit their response to the mitogen Con A, nor did it inhibit the responses of the purified protein derivative-specific T-cell line and clone. These results suggest that Cop 1 may be effective in suppression of experimental allergic encephalomyelitis, not only because of the selective stimulation of suppressor T cells, as we have previously demonstrated, but also by specific inhibition of BP-specific effector T cells.

A pilot trial of Cop 1 in exacerbating-remitting multiple sclerosis

Cop 1 is a random polymer (molecular weight, 14,000 to 23,000) simulating myelin basic protein. It is synthesized by polymerizing L-alanine, L-glutamic acid, L-lysine, and L-tyrosine. It suppresses but does not induce experimental allergic encephalomyelitis, an animal model of multiple sclerosis. It is not toxic in animals. In a double-blind, randomized, placebo-controlled pilot trial, we studied 50 patients with the exacerbating-remitting form of multiple sclerosis, who self-injected either 20 mg of Cop 1 dissolved in 1 ml of saline or saline alone daily for two years. Six of 23 patients in the placebo group (26 percent) and 14 of 25 patients in the Cop 1 group (56 percent) had no exacerbations (P = 0.045). There were 62 exacerbations in the placebo group and 16 in the Cop 1 group, yielding two-year averages of 2.7 and 0.6 per patient, respectively. Among patients who were less disabled on entry (Kurtzke disability score, 0 to 2), there were 2.7 exacerbations in the placebo group and 0.3 in the Cop 1 group over two years. Among patients who were more affected (Kurtzke disability score, 3 to 6), there was an average of 2.7 exacerbations in the placebo group and 1.0 in the Cop 1 group. Over two years, less disabled patients taking Cop 1 improved an average of 0.5 Kurtzke units; those taking placebo worsened an average of 1.2 Kurtzke units. More disabled patients worsened by 0.3 (Cop 1 group) and 0.4 (placebo group) unit. Irritation at injection sites and rare, transient vasomotor responses were observed as side effects. These results suggest that Cop 1 may be beneficial in patients with the exacerbating-remitting form of multiple sclerosis, but we emphasize that the study is a preliminary one and our data require confirmation by a more extensive clinical trial.

Effect of treatment with Copolymer 1 (Cop-1) on the in vivo and in vitro manifestations of experimental allergic encephalomyelitis (EAE)

Injections of Copolymer 1 (Cop-1), a synthetic cathodic polymer, have been reported to prevent and treat successfully acute and recurrent EAE and has been employed in patients with multiple sclerosis (MS). It has been suggested that the therapeutic effect is due to cell-mediated immune (CMI) cross-reactivity between Cop-1 and myelin basic protein (MBP), the antigen that induces EAE. We found that Cop-1 treatment of guinea pigs (GP) sensitized with MBP in adjuvant (20 micrograms/animal): (a) lowers the incidence of clinical disease (8/20 vs 14/15); (b) decreases severity of disease in affected GP; (c) has little effect on pathologic lesions (mean pathology index +/- SEM: 1.2 +/- 0.2 vs 1.6 +/- 0.3; P greater than 0.1). Lymphocytes of MBP-sensitized GP treated with Cop-1 exhibited in vitro proliferative responses to MBP equivalent to lymphocytes of untreated EAE-GP (14,134 +/- 6,532 vs 11,821 +/- 3,874; mean cpm +/- SEM). GP sensitized to MBP or Cop-1 (100 micrograms/animal) showed reactivity to the sensitizing antigen but little in vitro reactivity to the other antigen. There was no correlation between the in vitro lymphocytes response to MBP and Cop-1 in individual GP. Treatment of MBP sensitized GP with calf-thymus histone (CTH) also resulted in a lower incidence of clinical EAE with less severe disease in affected GP. There was little effect on the pathologic index and no evidence of either inhibition of MBP-induced lymphocyte proliferative responses or cross-reactivity between MBP and CTH. Thus, treatment with Cop-1 or CTH inhibits clinical manifestations of acute EAE without suppressing inflammatory cell infiltrates or sensitization to MBP.

Multiple sclerosis: trial of a synthetic polypeptide

A synthetic polypeptide, copolymer I (COP I), composed of alanine, glutamic acid, lysine, and tyrosine, has been demonstrated to be nonencephalitogenic and nontoxic in laboratory animals, yet it is capable of suppressing experimental allergic encephalomyelitis. A preliminary open trial examined the ability of COP I to alter the course of disease in 12 patients with chronic progressive and 4 with exacerbating-remitting multiple sclerosis (MS). After therapy for as long as two years or more, no undesirable side reaction was noted in any patient. Three patients with chronic progressive MS and 2 with exacerbating-remitting disease are better. These results, which may represent simply a placebo effect or may be a significant response, are now being examined in randomized, placebo-controlled, double-blind pilot trials.

Inhibition of experimental allergic encephalomyelitis by carrier administered prior to challenge with encephalitogenic peptide-carrier conjugate

Guinea pigs can be rendered unresponsive to experimental allergic encephalomyelitis (EAE) challenge by prior injections of myelin basic protein (BP) or peptides derived from BP. The synthesized tryptophan-containing peptide (TrpP, corresponding to residues 114-122) which is the primary encephalitogenic sequence in BP (for guinea pigs) had been conjugated to the non-central nervous system protein bovine serum albumin (BSA) and used for EAE challenge. It has been shown in this study that prechallenge treatment with the BSA carrier alone can significantly inhibit the induction of EAE by TrpP-BSA conjugate. That carrier treatment is immunologically specific was determined when prior treatment with cytochrome c did not protect animals from EAE challenge with TrpP conjugated to BSA. In addition, in disease induced with BP or TrpP, and while TrpP did protect guinea pigs challenged with TrpP, it did not protect those challenged with BP. This last finding raises the possibility of a second encephalitogenic sequence in BP or an important role for the carrier in the TrpP conjugate.

Genetic analysis of susceptibility to experimental allergic encephalomyelitis in guinea-pigs

Genetic analysis of susceptibility to experimental allergic encephalomyelitis (EAE) was performed in guinea-pigs. The results indicate the existence of two Ir genes to EAE in susceptible strain 13 guinea-pigs. One gene is linked to the major histocompatibility complex (MHC) of this species, while the other one is located outside the MHC. The two genes segregate independently and both of them must be expressed to render the animal susceptible to EAE.

Prevention of experimental allergic encephalomyelitis in Lewis rats with peptide 68-88 of guinea pig myelin basic protein

The highly encephalitogenic guinea pig peptide 68-88 has been used to develop an effective and reproducible model of protection in the Lewis rat. Doses as low as 0.1 nmol of peptide protected 70% of rats when injected intraperitoneally six and four weeks prior to challenge with 0.05 nmol of the peptide in complete Freund's adjuvant. Fragments derived from guinea pig peptide 68-88 by selective enzyme cleavage were then tested for their capacity to provide protection in this model system. These fragments had previously been well characterized both biochemically and immunologically. The protection provided by each fragment closely paralleled its capacity to induce disease. This suggests that the region of peptide 68-88 required for protection is similar to that needed for induction of experimental allergic encephalomyelitis and the other T-cell functions of the peptide. B-cells did not appear to participate; peptide 68-85, which has no capacity to produce antibody against peptide 68-88, gave full protection, while peptide 79-88, which contains the major B-cell determinant of the peptide, afforded no protection. Rat peptide 68-88 did not protect against challenge with the guinea pig peptide, demonstrating a critical role for serine 79. These studies support the concept that nonencephalitogenic agents do not protect against experimental allergic encephalomyelitis at doses comparable to those of encephalitogenic agents.

The effect of Cop 1, a synthetic polypeptide, on chronic relapsing experimental allergic encephalomyelitis in guinea pigs

Cop 1, a synthetic polypeptide, was evaluated for its effect on a chronic relapsing form of experimental allergic encephalomyelitis (EAE). Pretreatment of juvenile Strain 13 guinea pigs with Cop 1 in incomplete Freund's adjuvant (IFA) which were subsequently challenged with guinea pig spinal cord in complete Freund's adjuvant (CFA) had a marked effect in delaying or preventing the appearance of clinical signs of EAE. Administration of Cop 1 on appearance of clinical signs of EAE prevented progression of the first episode of the disease. Although relapses were not always prevented, they were modified on their duration and intensity both clinically and histologically.

Experimental allergic encephalitis: study of cellular immunity during disease suppression

Administration in complete Freund's adjuvant of encephalitogenic protein (EP), derived from central nervous tissue to guinea pigs, regularly results in the development of experimental allergic encephalitis (EAE) which leads to the death of the animals. Administration of EP in incomplete Freund's adjuvant at an appropriate time will completely suppress the clinical development of disease. Results reported herein show that animals receiving suppressive injections of EP for 7 days show depression of lymphocyte DNA synthesis and macrophage migration inhibition, but not of skin reactivity, in response to EP immediately following the injections, and subsequently show recovery of lymphocyte reactivity but do not develop clinical manifestations of EAE. Humoral or other factors may prevent the development of disease in these animals. Guinea pigs receiving injections of EP for 14 days show profound and prolonged depression of lymphocyte reactivity to EP and macrophage migration inhibition. Possible mechanisms for these results include a diminished number or function of reactive cells or activity of a population of cells with the capacity to suppress cellular immune responses. Nonspecific suppression of reactivity to an unrelated antigen during the suppressive injections was not observed.

Autoimmunity in multiple slcerosis: do we have an experimental model?

Experimental autoimmunity of the CNS has been well characterized--the antigen has been identified, effector cell specificity has been defined, and the relationship between cellular sensitization and antibody production has been partially clarified. In the guinea pig, experimental allergic encephalomyelitis (EAE) is induced by one injection of myelin basic protein in complete Freund's adjuvant (BP/CFA). If BP/CFA is preceded by repeated injections of basic protein in incomplete Freund's adjuvant (BP/IFA), EAE is not induced; the guinea pigs survive and ultimately produce antibody. Induction and prevention of EAE as well as antibody induction by this schedule are dependent on the presence of the intact encephalitogenic (T-cell) site in the polypeptide used for sensitization and preimmunization. In contrast, B cell sites (those peptide sequences which bind antibody) are independent of the T-cell site. At least 5 specific antigenic regions (B-cell sites) have been demonstrated in the BP molecule. High mycobacteria levels bypass the specificity requirement of helper T-cells but cannot bypass the specificity requirement of effector T-cells. In spite of the sophisticated immunologic techniques available, our knowledge of humoral and cellular sensitivity in multiple sclerosis (MS) patients is very limited. The experimental demonstration of an analogy between EAE and MS is weak: a) Demonstration of BP-sensitized cells or BP-specific antibodies in peripheral blood of MS patients has not been successful. b) Anti-myelin serum factors reported to be associated with both disease states (experimental autoimmunity and MS) are clearly not identical. Nevertheless, successful treatment of EAE in animals by BP/IFA injections has encouraged consideration of clinical trials to test the therapeutic value of BP injections in MS patients. If successful, the question will be answered: if unsuccessful, the dilemma still remains.

Evidence for suppressor cells in Lewis rats' experimental allergic encephalomyelitis

In this work we demonstrate a suppressive activity on the induction of experimental allergic encephalomyelitis (EAE) in Lewis rats, transferable to syngeneic animals, challenged with encephalitogenic mixture (myelin basic protein, complete Freud's adjuvant plus Bordetella pertussis organisms) 24 h later. This activity is probably effected by T cells and not by (an) inhibitory serum factor(s). The induction of this specific protection could be due to the penetration of the myelin basic protein antigen into the thymus where we first found suppressive cells. From the thymus, suppressor cells could then emigrate to spleen (on day 15) and to nondraining lymph nodes (on day 17). In the course of normal EAE in Lewis rats and especially at the time of self cure, this suppression is not demonstrated, but possible.

Bovine myelin basic protein: immunochemical specificity examined by the macrophage migration inhibition test

Guinea pigs were injected with saline or with one of the following antigens incorporated into Freund's complete adjuvant: Bovine myelin basic protein (MBP), lysozyme, carboxymethylated lysozyme, or a crude commercial calf thymus histone preparation. Examination of the migration of peritoneal cells from these animals in the presence (50 microgram/ml) or the absence of the antigens revealed, at most, a slight one-way form of cross-reactivity between MBP on the one hand and the histone preparation--and possibly also lysozyme--on the other. This was observed only with cells from animals injected with the two last-mentioned antigens. Cells from animals sensitized with either histone or lysozyme mixed with poly AU instead of Freund's complete adjuvant were also slightly inhibited in their migration by the bovine MBP. Cells from animals injected with complete Freund's adjuvant alone or with the purified protein derivative of tuberculin (PPD) in poly AU did not react to MBP. Thus, in contrast to the high degree of internal cross-reactivity shown previously MBP shows a low degree of cross-reactivity with either ordered or unordered forms of some unrelated basic proteins.

Autoimmune disease antigens

The first step towards understanding the cellular interaction which results in autoimmune disease is to determine what triggers the recognition between a specific autoimmune antigen determinant and the cellular receptor. In this review, we have focused on the antigen inducing experimental allergic encephalitis (EAE) because the antigen has been characterized and a relatively large body of information on its biological activities has been accumulated. Clearly, a specific allergic encephalitis-producing determinant is present and is represented on a relatively small portion of the molecule. The determinant induces a wide variety of biological reactivities, some of which are classed as cellular mediated. An attempt is made to dissect activities such as blast transformation (BT), migration inhibitory factor (MIF), in vivo delayed type hypersensitivity reaction (DTH) and EAE and to relate them to the structural requirements which the determinants possess. The complexities which arise indicate that subpopulations of cells with different receptor activities may respond selectively and that recognition of the receptor is produced by an EAE determinant consisting of three amino acids in a specific linear sequence. Furthermore, under experimental circumstances the EAE activity can be dissociated from the other activities (BT, MIF, DTH), indicating that while these tests are used generally to follow various human autoimmune disease activities, they may represent the reaction of a broad spectrum of cells.

Effect of a synthetic polypeptide (COP 1) on patients with multiple sclerosis and with acute disseminated encephalomeylitis. Preliminary report

Three patients with acute disseminated encephalomyelitis (ADE) and 4 patients in the terminal stages of multiple sclerosis (MS) were subjected to treatment with Cop 1, a synthetic copolymer of amino acids, which had previously been shown to have a beneficial effect in the treatment of experimental allergic encephalomyelitis (EAE). Under the treatment, the ADE patients recovered completely within 3 weeks, but 1 of 2 control cases treated with steroids showed complete recovery as well. The MS patients did not show any significant change in their motor function; however, 2 of them showed some improvement in vision and speech capacity. It is too early to conclude whether this improvement is related to the treatment. No side effect was observed in any of the patients treated with Cop. 1.