Neuronal antigens modulate the immune response associated with experimental autoimmune encephalomyelitis

Rats primed with bovine myelin (BM) in complete Freunds adjuvant, develop acute experimental autoimmune encephalomyelitis (EAE). We have previously described that intraperitoneal administration prior to the active induction of the disease of a bovine synaptosomal fraction (BSF) and BM were effective ways of suppressing EAE. We found that both treatments diminish the incidence of the disease and reduced biochemical and histological alterations of the central nervous system (CNS). To characterize this suppression process, in this study we examined the antigen-specific immune response in animals protected from EAE. Lymph node mononuclear cells derived from sick EAE rats, as well as from those protected by BM and BSF, showed strong myelin basic protein (MBP) proliferation. Analysis of the humoral response against MBP showed a significant diminution of IgG2b anti-MBP titres in protected BM and BSF rats in contrast to sick EAE rats whose condition could be related to a diminished anti-MBP Th1 response. Finally, cells from rats protected by BSF and BM reduced the incidence of EAE when they were adoptively transferred into animals prior to active induction of the disease. These results suggest that a mechanism based on the generation of regulatory cells and immune deviation could account for the EAE suppression mediated by myelin as well as synaptosomal antigens.     

Leuprolide Acetate, a GnRH Agonist, Improves Experimental Autoimmune Encephalomyelitis: A Possible Therapy for Multiple Sclerosis

Gonadotrophin-releasing hormone (GnRH), a well known hypothalamic neuropeptide, has been reported to possess neurotrophic properties. Leuprolide acetate, a synthetic analogue of GnRH is considered to be a very safe and tolerable drug and it has been used for diverse clinical applications, including the treatment of prostate cancer, endometriosis, uterine fibroids, central precocious puberty and in vitro fertilization techniques. The present study was designed to determine whether Leuprolide acetate administration, exerts neurotrophic effects on clinical signs, body weight gain, neurofilaments (NFs) and myelin basic protein (MBP) expression, axonal morphometry and cell infiltration in spinal cord of experimental autoimmune encephalomyelitis (EAE) rats. In this work, we have found that Leuprolide acetate treatment decreases the severity of clinical signs of locomotion, induces a significantly greater body weight gain, increases the MBP and NFs expression, axonal area and cell infiltration in EAE animals. These results suggest the use of this agonist as a potential therapeutic approach for multiple sclerosis.     

Calpain inhibitor attenuated optic nerve damage in acute optic neuritis in rats

Optic neuritis (ON), which is an acute inflammatory autoimmune demyelinating disease of the central nervous system (CNS), often occurs in multiple sclerosis (MS). ON is an early diagnostic sign in most MS patients caused by damage to the optic nerve leading to visual dysfunction. Various features of both MS and ON can be studied following induction of experimental autoimmune encephalomyelitis (EAE), an animal model of MS, in Lewis rats. Inflammation and cell death in the optic nerve, with subsequent damage to the retinal ganglion cells in the retina, are thought to correlate with visual dysfunction. Thus, characterizing the pathophysiological changes that lead to visual dysfunction in EAE animals may help develop novel targets for therapeutic intervention. We treated EAE animals with and without the calpain inhibitor calpeptin (CP). Our studies demonstrated that the Ca²⁺‐activated neutral protease calpain was upregulated in the optic nerve following induction of EAE at the onset of clinical signs (OCS) of the disease, and these changes were attenuated following treatment with CP. These reductions correlated with decreases in inflammation (cytokines, iNOS, COX‐2, and NF‐κB), and microgliosis (i.e. activated microglia). We observed that calpain inhibition reduced astrogliosis (reactive astroglia) and expression of aquaporin 4 (AQP4). The balance of Th1/Th2 cytokine production and also expression of the Th1‐related CCR5 and CXCR3 chemokine receptors influence many pathological processes and play both causative and protective roles in neuron damage. Our data indicated that CP suppressed cytokine imbalances. Also, Bax:Bcl‐2 ratio, production of tBid, PARP‐1, expression and activities of calpain and caspases, and internucleosomal DNA fragmentation were attenuated after treatment with CP. Our results demonstrated that CP decreased demyelination [loss of myelin basic protein (MBP)] and axonal damage [increase in dephosphorylated neurofilament protein (de‐NFP)], and also promoted intracellular neuroprotective pathways in optic nerve in EAE rats. Thus, these data suggest that calpain is involved in inflammatory as well as in neurodegenerative aspects of the disease and may be a promising target for treating ON in EAE and MS.     

Role of the clotting system in the pathogenesis of neuroimmunologic disease

Experimental allergic encephalomyelitis (EAE) is a prototypic neuroautoimmune disease involving sensitization to central nervous system myelin basic protein (MBP). Our studies of the clotting system and ensuing fibrinolysis implicate coagulation and cleavage of fibrin within or on the luminal surface of the cerebrovasculature as events initiating the inflammation characterizing EAE. Among recipient rats injected with MPB-primed, cultured-activated lymph node cells, opening of the blood-brain barrier (BBB) and deposition of perivascular fibrin within the spinal cord occur in parallel 1 day before onset of clinical signs of EAE. Daily treatment of recipient rats with trans-4-(aminomethyl)cyclohexanecarboxylic acid, a synthetic product that specifically inhibits plasminogen activator derived from endothelial cells, results in marked reduction of increased permeability of the BBB and suppression of clinical signs of EAE. We postulate that the critical event precipitating EAE is binding of circulating MBP-reactive immune effector cells to MBP immunodeterminants on the surface of cerebrovascular endothelial cells. Coagulation and ensuing fibrinolysis occur at sites of binding of effector cells to cerebrovascular endothelium. Release of biologically active peptides cleaved from fibrin open the BBB, thereby setting the stage for the cascade of inflammatory events culminating in clinical manifestations of EAE.     

Suppression of experimental allergic encephalomyelitis in Lewis rats treated with myelin basic protein-liposome complexes: clinical, histopathological, and cell-mediated immunity correlates

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

Adoptive transfer of experimental allergic encephalomyelitis with activated spleen cells: Comparison of in vitro activation by concanavalin A and myelin basic protein

Adoptive transfer of experimental allergic encephalomyelitis (EAE) was carried out in Lewis rats using splenic lymphocytes incubated in vitro with either concanavalin A (Con A) or myelin basic protein (MBP). Requirements were established for sensitization of donors, culture conditions, numbers of transferred cells, and incubation period of EAE in recipients. These were strikingly similar whether Con A or MBP was used. In addition, cellular proliferation in vitro was not required in either system, but proliferation after transfer to the recipient was essential for the development of clinical signs and histological lesions. These methods have potential value for analyzing mechanisms of immune induction in this classic model of autoimmune disease.     

Ellagic acid protects from myelin-associated sphingolipid loss in experimental autoimmune encephalomyelitis

Experimental autoimmune encephalomyelitis (EAE), the most common model for multiple sclerosis, is characterized by inflammatory cell infiltration into the central nervous system and demyelination. Previous studies have demonstrated that administration of some polyphenols may reduce the neurological alterations of EAE. In this work, we show that ellagic acid, a polyphenolic compound, is beneficial in EAE, most likely through stimulation of ceramide biosynthesis within the brain. EAE was induced in Lewis rats by injection of guinea-pig spinal cord tissue along with Freund's complete adjuvant containing Mycobacterium tuberculosis. Clinical signs first appeared at day 8 post-immunization and reached a peak within 3?days, coincident with reduction of myelin basic protein (MBP) in the cortex. Sphingolipids, the other major components of myelin, also decreased at the acute phase of EAE, both in the cerebral cortex and in the spinal cord. In rats receiving ellagic acid in the drinking water from 2?days before immunization, the onset of the disease was delayed and clinical signs were reduced. This amelioration of clinical signs was accompanied by sustained levels of both MBP and sphingolipid in the cortex, without apparent changes in infiltration of inflammatory CD3+ T-cells, microglial activation, or weight loss, which together suggest a neuroprotective effect of ellagic acid. Finally, in glioma and oligodendroglioma cells we demonstrate that urolithins, the ellagic acid metabolites that circulate in plasma, stimulate the synthesis of ceramide. Together these data suggest that ellagic acid consumption protects against demyelination in rats with induced EAE, likely by a mechanism involving sphingolipid synthesis.     

Peroxisome proliferator-activated receptor-gamma agonist 15-deoxy-Delta(12,14)-prostaglandin J(2) ameliorates experimental autoimmune encephalomyelitis

Peroxisome proliferator-activated receptors (PPAR) are members of a nuclear hormone receptor superfamily that includes receptors for steroids, retinoids, and thyroid hormone, all of which are known to affect the immune response. Previous studies dealing with PPAR-gamma expression in the immune system have been limited. Recently, PPAR-gamma was identified in monocyte/macrophage cells. In this study we examined the role of PPAR-gamma in experimental autoimmune encephalomyelitis (EAE), an animal model for the human disease multiple sclerosis. The hypothesis we are testing is whether PPAR-gamma plays an important role in EAE pathogenesis and whether PPAR-gamma ligands can inhibit the clinical expression of EAE. Initial studies have shown that the presence of the PPAR-gamma ligand 15-deoxy-Delta(12,14)-PGJ(2) (15d-PGJ2) inhibits the proliferation of Ag-specific T cells from the spleen of myelin basic protein Ac(1-11) TCR-transgenic mice. 15d-PGJ2 suppressed IFN-gamma, IL-10, and IL-4 production by both Con A- and myelin basic protein Ac(1-11) peptide-stimulated lymphocytes as determined by ELISA and ELISPOT assay. Culture of encephalitogenic T cells with 15d-PGJ2 in the presence of Ag reduced the ability of these cells to adoptively transfer EAE. Examination of the target organ, the CNS, during the course of EAE revealed expression of PPAR-gamma in the spinal cord inflammatory infiltrate. Administration of 15d-PGJ2 before and at the onset of clinical signs of EAE significantly reduced the severity of disease. These results suggest that PPAR-gamma ligands may be a novel therapeutic agent for diseases such as multiple sclerosis.     

Myelin/oligodendrocyte glycoprotein-induced autoimmune encephalomyelitis in common marmosets: the encephalitogenic T cell epitope pMOG24-36 is presented by a monomorphic MHC class II molecule

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

Experimental allergic encephalomyelitis: clinical disease and enhanced cellular transfer in the absence of lymphocyte proliferative responses against syngeneic MBP

Experimental allergic encephalomyelitis (EAE) was induced in Lewis rats using several different immunization protocols, and draining lymph node cells from these animals were assayed for proliferation against heterologous, homologous, and syngeneic MBP, and syngeneic spinal cord. Proliferative responses were largely stimulated by nonsyngeneic antigenic determinants and correlated better with the antigen used to induce EAE than with signs of autoimmune disease. Lymph node cells from rats immunized with either guinea pig spinal cord or syngeneic MBP did not proliferate measurably when restimulated in vitro with syngeneic MBP, yet lymphoid cells from these animals were enhanced in their capacity to transfer EAE following in vitro stimulation with syngeneic MBP.     

LF 15-0195 inhibits the development of rat central nervous system autoimmunity by inducing long-lasting tolerance in autoreactive CD4 T cells

Experimental autoimmune encephalomyelitis (EAE) is a T cell-dependent autoimmune disease induced in susceptible animals by a single immunization with myelin basic protein (MBP). LF 15-0195 is a novel immunosuppressor that has been shown to have a potent immunosuppressive effect in several pathological manifestations. The purpose of this study was to investigate the effect of this drug on the induction and progression of established rat EAE and to dissect the mechanisms involved. We show that LF 15-0195 administration at the time of MBP immunization reduces the incidence and severity of EAE in Lewis rats. This drug also inhibits ongoing and passively induced EAE, indicating that LF 15-0195 affects already differentiated pathogenic lymphocytes. Compared with lymph node cells from untreated rats, lymphocytes from MBP-immunized rats treated with LF 15-0195 proliferated equally well in response to MBP in vitro, while their ability to produce effector cytokines and to transfer EAE into syngeneic recipients was significantly reduced. This phenomenon is stable and long-lasting. Indeed, neither IL-12 nor repeated stimulation with naive APC and MBP in vitro rendered MBP-specific CD4 T cells from protected rats encephalitogenic. In conclusion, LF 15-0195 treatment suppresses EAE by interfering with both the differentiation and effector functions of autoantigen-specific CD4 T cells.     

Effects of progesterone in the spinal cord of a mouse model of multiple sclerosis

The spinal cord is a target of progesterone (PROG), as demonstrated by the expression of intracellular and membrane PROG receptors and by its myelinating and neuroprotective effects in trauma and neurodegeneration. Here we studied PROG effects in mice with experimental autoimmune encephalomyelitis (EAE), a model of multiple sclerosis characterized by demyelination and immune cell infiltration in the spinal cord. Female C57BL/6 mice were immunized with a myelin oligodendrocyte glycoprotein peptide (MOG_40–54). One week before EAE induction, mice received single pellets of PROG weighing either 20 or 100 mg or remained free of steroid treatment. On average, mice developed clinical signs of EAE 9–10 days following MOG administration. The spinal cord white matter of EAE mice showed inflammatory cell infiltration and circumscribed demyelinating areas, demonstrated by reductions of luxol fast blue (LFB) staining, myelin basic protein (MBP) and proteolipid protein (PLP) immunoreactivity (IR) and PLP mRNA expression. In motoneurons, EAE reduced the expression of the alpha 3 subunit of Na,K-ATPase mRNA. In contrast, EAE mice receiving PROG showed less inflammatory cell infiltration, recovery of myelin proteins and normal grain density of neuronal Na,K-ATPase mRNA. Clinically, PROG produced a moderate delay of disease onset and reduced the clinical scores. Thus, PROG attenuated disease severity, and reduced the inflammatory response and the occurrence of demyelination in the spinal cord during the acute phase of EAE.     

Genetic control of resistance to clinical EAE accompanied by histological symptoms

The susceptibility of rats to experimental allergic encephalomyelitis (EAE) induced by myelin basic protein (MBP) was studied in a variety of genetic crosses. Rats were evaluated according to weight loss, neurological symptoms, and histological criteria. The results demonstrate that three different types of genes are involved in susceptibility. AnRTI-linked gene is necessary but not sufficient for full expression of EAE induced by MBP in complete Freund's adjuvant (CFA). Additional genes are required for the occurrence of histological EAE, but a full-blown inflammatory reaction is not sufficient for the expression of clinical EAE. A third type of gene, which can be demonstrated in appropriate crosses, is required for the consistent expression of clinical symptoms. Dominant genes for resistance to clinical symptoms were transferred to the Lewis (LEW) background from the BN.B1 strain through two generations of backcrossing. Thus, there are genetically controlled mechanisms involved in the neurological expression of EAE which are independent of the inflammatory reaction as observed in central nervous system (CNS) histology.     

Myelin lipophilin-induced demyelinating disease of the central nervous system

Purified lipophilin, a hydrophobic lipoprotein of myelin, induces a cell-mediated demyelinating disease of the central nervous system similar to experimental allergic encephalomyelitis (EAE) induced by the myelin basic protein (MBP). Guinea pigs challenged with lipophilin (emulsified with CFA) developed clinical and histological signs of disease indistinguishable from those developed by animals similarly challenged with MBP. Both lipophilin and MBP induced and elicited delayed-type hypersensitivity in animals challenged with respective antigens. Tryptophan, an essential component of the MBP-determinant for disease in guinea pigs, is required for the encephalitogenicity of lipophilin.     

Role of macrophage-myelin basic protein interaction in the induction of experimental allergic encephalomyelitis in Lewis rats

Stimulated peritoneal exudate cells (PEC) containing activated macrophages (M phi) of Lewis (Le) rats were exposed for 1 hr in vivo or in vitro to radioiodinated soluble myelin basic protein (MBP) or MBP incorporated into magnetic microspheres (MBP-microspheres). The uptake by M phi of the dose of microsphere-bound MBP averaged 6.2%, whereas the average uptake of soluble MBP was 0.17%. Naive rats were sensitized with M phi-associated MBP or M phi-associated MBP-microspheres via the hind footpads without the aid of conventional immunologic adjuvants. Draining lymph node cells (LNC) or spleen cells from sensitized rats were cultured for 3 days with guinea pig MBP (GPMBP) alone or in combination with concanavalin A (Con A), then injected i.v. into naive recipients. Clinical signs of experimental allergic encephalomyelitis (EAE) appeared 6 days after transfer of LNC or spleen cells, and typical CNS lesions were seen in recipients sacrificed 10 to 14 days after transfer. The challenge of MO-MBP-sensitized rats with MBP-CFA resulted in severe clinical signs of EAE marked by an accelerated onset of neurologic symptoms.     

Measurement of cell-mediated inflammation in experimental murine autoimmune encephalomyelitis by radioisotopic labeling.

A radioisotopic index test was used to detect that time of onset and intensity of cell-mediated immune inflammation of experimental autoimmune encephalomyelitis (EAE) in mice. Mice were tested at various time intervals after an encephalitogenic immunization with mouse spinal cord to homogenate for delayed-type hypersensitivity (DTH) to myelin basic protein (MBP) by intradermal challenge with antigen in the ear pinna. After 25 hr, the intensity of DTH was measured by 125I-radiometry which depends upon the migration of 125I-UdR radiolabeled mononuclear cells into the antigen depot. Cells reactive to MBP were detected by the ear assay as early as 7 days after the initial encephalitogenic sensitization. The degree of cell-mediated immune inflammation in the brain and spinal cord during the evolution of EAE was also measured by a radioisotopic technique; increased 125I-UdR uptake could be detected in the brain 3 to 4 days before the onset of signs of EAE at days 11 to 12, whereas 125I-UdR in the spinal cord was detected only 1 day before, or concomitant with, the onset of signs of EAE. Both, or concomitant with, the onset of signs of EAE. Both the "ear" and "organ" radiometric index tests are useful in measuring the degree of cell-mediated inflammation in EAE, and supplement routine histopathological and observational assessments.     

Experimental autoimmune encephalomyelitis on the SJL mouse: effect of gamma delta T cell depletion on chemokine and chemokine receptor expression in the central nervous system

Experimental autoimmune encephalomyelitis (EAE) is a demyelinating disease of the central nervous system (CNS) that is a model for multiple sclerosis. Previously, we showed that depletion of gamma delta T cells significantly reduced clinical and pathological signs of disease, which was associated with reduced expression of IL-1 beta, IL-6, TNF-alpha, and lymphotoxin at disease onset and a more persistent reduction in IFN-gamma. In this study, we analyzed the effect of gamma delta T cell depletion on chemokine and chemokine receptor expression. In the CNS of control EAE mice, mRNAs for RANTES, eotaxin, macrophage-inflammatory protein (MIP)-1 alpha, MIP-1 beta, MIP-2, inducible protein-10, and monocyte chemoattractant protein-1 were detected at disease onset, increased as disease progressed, and fell as clinical signs improved. In gamma delta T cell-depleted animals, all of the chemokine mRNAs were reduced at disease onset; but at the height of disease, expression was variable and showed no differences from control animals. mRNA levels then fell in parallel with control EAE mice. ELISA data confirmed reduced expression of MIP-1 alpha and monocyte chemoattractant protein-1 at disease onset in gamma delta T cell-depleted mice, and total T cell numbers were also reduced. In normal CNS mRNAs for CCR1, CCR3, and CCR5 were observed, and these were elevated in EAE animals. mRNAs for CCR2 were also detected in the CNS of affected mice. Depletion of gamma delta T cells reduced expression of CCR1 and CCR5 at disease onset only. We conclude that gamma delta T cells contribute to the development of EAE by promoting an inflammatory environment that serves to accelerate the inflammatory process in the CNS.     

RTL551 treatment of EAE reduces CD226 and T-bet+ CD4 T cells in periphery and prevents infiltration of T-bet+ IL-17, IFN-γ producing T cells into CNS

Recombinant T cell receptor ligands (RTLs) that target encephalitogenic T-cells can reverse clinical and histological signs of EAE, and are currently in clinical trials for treatment of multiple sclerosis. To evaluate possible regulatory mechanisms, we tested effects of RTL therapy on expression of pathogenic and effector T-cell maturation markers, CD226, T-bet and CD44, by CD4+ Th1 cells early after treatment of MOG-35-55 peptide-induced EAE in C57BL/6 mice. We showed that 1-5 daily injections of RTL551 (two-domain I-A(b) covalently linked to MOG-35-55 peptide), but not the control RTL550 ("empty" two-domain I-A(b) without a bound peptide) or Vehicle, reduced clinical signs of EAE, prevented trafficking of cells outside the spleen, significantly reduced the frequency of CD226 and T-bet expressing CD4+ T-cells in blood and inhibited expansion of CD44 expressing CD4+ T-cells in blood and spleen. Concomitantly, RTL551 selectively reduced CNS inflammatory lesions, absolute numbers of CNS infiltrating T-bet expressing CD4+ T-cells and IL-17 and IFN-γ secretion by CNS derived MOG-35-55 reactive cells cultured ex vivo. These novel results demonstrate that a major effect of RTL therapy is to attenuate Th1 specific changes in CD4+ T-cells during EAE and prevent expansion of effector T-cells that mediate clinical signs and CNS inflammation in EAE.     

Oral tolerance in experimental autoimmune encephalomyelitis. III. Evidence for clonal anergy.

We have recently reported that experimental autoimmune encephalomyelitis (EAE) can be suppressed by the oral administration of myelin basic protein (MBP). The oral introduction of 20 mg MBP together with a trypsin inhibitor results in inhibition of EAE clinical signs, decreased CNS histopathologic changes and dramatically reduced MBP-specific proliferative responses in fed and challenged Lewis rats. In the present study, we have investigated the mechanism underlying MBP-induced oral tolerance in EAE. Neither lymphoid cells (lymph node cells, spleen cells, Peyer's patch lymphocytes, thymocytes) nor humoral elements derived from tolerant donors were capable of transferring the tolerance to naive recipients. Moreover, lymphoid cells obtained from orally tolerant donors exhibited a marked decrease in their capacity to transfer EAE to naive recipient rats, even after in vitro activation with MBP or Con A. We observed that EAE could be readily transferred into orally tolerant rats using MBP-specific encephalitogenic T cell lines. In vitro cell mixing studies showed that the proliferation of lymphocytes from MBP-sensitized donors was not inhibited by the addition of lymphoid cells from tolerant donors, arguing against the role of a suppressor cell. Investigation of MBP-stimulated lymphokine production showed that both IL-2 and IFN-gamma levels were substantially decreased in spleen and lymph node cell cultures from MBP-fed rats compared to vehicle-fed control animals. Furthermore, limiting dilution analyses revealed that MBP-fed rats exhibited a profound decrease in MBP-reactive, IL-2-secreting lymphocytes relative to control animals. Thus, because lymphocytes from MBP-fed rats neither proliferate nor secrete IL-2 or IFN-gamma in response to MBP and we can find no compelling evidence for the role of suppressor cells, we propose that the oral administration of MBP results in a state of clonal anergy.     

Cerebrospinal fluid and serum oligoclonal IgG bands in rabbits with experimental allergic encephalomyelitis

Rabbits sensitized with whole nervous tissue or myelin basic protein (MBP) plus adjuvant and developing experimental allergic encephalomyelitis (EAE) were studied for the presence of oligoclonal immunoglobulin (Ig) bands in spinal fluid and serum. Samples obtained prior to sensitization and at the time of sacrifice were concentrated and subjected to agar gel electrophoresis. Of 11 rabbits receiving whole nervous tissue and developing severe clinical signs of EAE, 7 showed new oligoclonal Ig bands in spinal fluid and in serum obtained 19 days or more after sensitization. With MBP sensitization, 2 of 6 rabbits exhibited new spinal fluid bands, while all 6 rabbits studied demonstrated serum banding. The bands were identified as IgG by immunochemical studies using peroxidase-labeled antisera and byStaph. protein A absorption. The majority of animals showed no banding in presensitization samples. The finding of oligoclonal IgG in EAE reveals yet another immunologic correlation between EAE and the human demyelinating disease, multiple sclerosis.