Brain transplantation in genetic analysis of experimental allergic encephalomyelitis.
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Biomedical subjects
Publications and source records attributed to F D Lublin.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
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A 42-year-old male with advanced multiple sclerosis had severe left-sided trigeminal neuralgia in the maxillary and mandibular divisions that was extremely difficult to control with medications. Glycerol injection in the gasserian cystern provided only temporary results. Two electrodes were implanted epidurally at the C1-2 level, one in the midline and the other to the left of midline. Electrical stimulation produced complete relief from the painful paroxysms.
Groups of adult male Syrian hamsters were kept in a long photoperiod (LD 14:10) or a short photoperiod (LD 10:14). After 12 weeks, half of the animals in each light:dark cycle were immunized with an immunogenic amino acid polymer. Exposure to short photoperiod was associated with a significant reduction in testicular, accessory sex organ, splenic and brown fat weights. However, photoperiod length did not influence whole body, thymic, adrenal or kidney weights. Spleens of immunized animals in the long photoperiod were significantly heavier than those of unimmunized animals in the long photoperiod, and both were heavier than spleens from immunized or unimmuized animals in the short photoperiod. This reflected increased splenic lymphocyte and macrophage counts. However, there was no difference in antibody production between animals kept in different photoperiods. These results demonstrate that the daily photoperiod length affects both hamster reproductive competence as well as selected immune parameters (splenic weight and mononuclear cell hyperplasia) but does not alter antibody production.
Mice with the dysmyelinating mutation shiverer were studied by measuring the activity of two protein methylases and myelin marker enzymes in the brain. It was observed that S-adenosylmethionine:protein-lysine N-methyltransferase (protein methylase III, EC. 2.1.1.43) activity is significantly reduced in phenotypically affected homozygous shiverer (shi/shi) mutant mouse brain compared to the unaffected heterozygous littermate brain. This reduction in enzyme activity is manifested mainly by reduced formation of trimethyllysine during the in vitro methylation of histone. In contrast, myelin marker enzymes such as 2',3'-cyclic nucleotide 3'-phosphohydrolase and 5'-nucleotidase as well as S-adenosyl-methionine:protein-carboxyl O-methyltransferase (protein methylase II, EC. 2.1.1.24) activities were not significantly affected in these strains of mice.
A heterotopic transplant paradigm was developed for its potential usefulness in dissecting genetically determined immune and central nervous system (CNS) components in the induction of experimental allergic encephalomyelitis (EAE). EAE is a cell-mediated, organ-specific, autoimmune disease producing inflammatory demyelination in the CNS. Susceptibility to EAE is determined by multiple genes and reflects both immune competence and target tissue responses. Syngeneic fetal CNS was heterotopically transplanted into the anterior chamber of the eye or beneath the capsule of the kidney of adult SJL or (SJL X BALB/c)F1 mice. Transplants usually survived better in the eye than the kidney. Six to eight weeks after transplantation, some mice were immunized for EAE. Immunized mice developed clinical and pathological signs of EAE in 12 to 15 days. The placement of CNS tissue into the eye or kidney prior to immunization did not suppress induction of EAE. Transplants in either location, in immunized mice, manifested perivascular inflammation and demyelination similar to that seen in the host CNS. However, transplants in mice not immunized for EAE, but maintained an equal time period after transplantation, did not demonstrate these features. The ability to produce the specific pathologic lesions of EAE in CNS tissue transplanted outside the CNS allows the design of studies of the tissue localization of genetic restrictions to development of EAE.
The effect of treatment with the antineoplastic, immunomodulatory agent mitoxantrone on the course of acute and relapsing experimental allergic encephalomyelitis (EAE) in the mouse has been studied. Untreated mice immunized to produce acute EAE had an 81% incidence of clinical disease and 100% incidence of pathologic disease. Mice treated with mitoxantrone at a dose of 0.5 mg/kg daily for the 10 days following immunization did not develop any clinical signs and had minimal pathologic signs of disease. A dose of 0.25 mg/kg gave an intermediate response. Untreated mice immunized for relapsing EAE had a 100% incidence of disease with an average onset of disease on Day 148. Mice treated with mitoxantrone at a dose of 0.05 mg/kg three times weekly for 12 weeks following immunization had a 67% incidence of clinical disease with a significant delay in the average onset date to Day 279. These results indicate that mitoxantrone was highly effective in suppressing development of acute EAE. Mitoxantrone delayed the onset of relapsing EAE in mice, but did not fully inhibit the eventual expression of the disease. These studies suggest that the use of cytotoxic therapies in the treatment of autoimmune diseases may require periodic cycles of therapy to block disease expression.
Myelin basic protein (MBP)-specific protein-arginine N-methyltransferase (protein methylase I) activity in homozygous shiverer (shi/shi) mutant mouse brain is significantly higher than in the normal littermate brain at the onset of myelination. While the enzyme activity (expressed as pmol of S-adenosyl-L-[methyl-14C]methionine used/min/mg enzyme protein) increases coincidently during the period of myelination in the normal brain (15-18 days of age), it decreases significantly in the mutant brain during this period of time. These results are in contrast to those found with another dysmyelinating mutant, jimpy (jp/Y) mice, in which the enzyme activity in the mutant brains is similar to that in the normal animals but remains unchanged during the myelination process. There is no difference in the weight and protein concentration of the normal and shiverer mutant brains with corresponding ages, and the histone-specific protein methylase I activity is also unaffected in the shiverer brain.
Acute experimental allergic encephalomyelitis (EAE) is an autoimmune disease involving the central nervous system (CNS) that can be elicited in susceptible strains of mice by the subcutaneous inoculation of mouse spinal cord homogenate (MSCH) in conjunction with complete Freund's adjuvant. In order to localize the physiological compartment conveying susceptibility to mice for EAE induction, hematopoietic radiation chimeras were prepared between the highly responsive SJL and low responder B10.S strains. Upon challenge with SJL MSCH preparations, high incidence of clinical disease was exhibited by B10.S----SJL chimeras but not by SJL----B10.S mice, suggesting that non-bone-marrow-derived factors were influencing development of disease. The incidence of histological lesions in the CNS was high for virtually all experimental and control groups except normal B10.S and B10.S----B10.S reconstituted mice. In contrast, challenge with B10.S MSCH induced a high clinical incidence of EAE in both B10.S----SJL and SJL----B10.S chimeras, indicating a possible interstrain difference in the immunogenicity of relevant CNS antigens.
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The relapsing form of experimental allergic encephalomyelitis (EAE) has been shown to be a useful model of the human disease, multiple sclerosis. This autoimmune disease is organ specific and appears to be primarily a cell-mediated disorder similar to the acute form of EAE. In order to understand better the regulatory mechanisms responsible for development of disease, radiation bone marrow chimeras were prepared between the highly susceptible SJL/J mouse and the resistant B10.S mouse. A high incidence of disease was seen in SJL----SJL and B10.S----SJL chimeras. A low incidence was seen in B10.S----B10.S and SJL----B10.S chimeras. The results were similar in mice immunized with CNS antigen of either BALB/c or B10.S origin. These results demonstrate that the immune system from the resistant B10.S mouse is capable of mediating relapsing EAE when present in a susceptible SJL host, while the SJL immune system was restricted in its ability to induce disease when present in a resistant B10.S host. This would indicate that restriction to the development of EAE may reside outside of the immune system, perhaps involving antigen recognition or presentation in the CNS itself.
Relapsing experimental allergic encephalomyelitis (EAE), an autoimmune disorder resembling multiple sclerosis, has been produced by inoculating SJL/J mice with spinal cord or myelin basic protein in appropriate adjuvants. To determine whether initially sensitized lymphocytes or the persistence of antigen depots in the animal were responsible for the relapsing episodes of inflammatory demyelination, adoptive transfer studies were undertaken utilizing lymphocytes from relapsing EAE-immunized donors transferred directly or after in vitro culture. In direct-transfer studies donor lymphocytes produced clinical and pathological signs of relapsing EAE in 3 of 7 recipients of lymph node lymphocytes and 1 of 5 recipients of splenic lymphocytes. In vitro culture of lymphocytes in myelin basic protein or T cell growth factor prior to transfer increased both the incidence of disease and the number of animals having relapses, and allowed transfer with fewer lymphocytes. Because all animals had delayed onset of disease, this study demonstrates that the ability to develop relapsing inflammatory demyelination is transferable with lymphocytes and does not require the presence of antigen.
R-EAE is a valuable model for human MS. Table 2 outlines the similarities between R-EAE and MS. The clinical course and pathologic changes seen in this model accurately reflect the pattern of MS. The immunologic changes seen in animals with R-EAE also are similar to those seen in MS. Therefore, the clinicopathologic features of MS can be duplicated with a purely autoimmune model. Although this is of considerable pathogenic significance in understanding MS, we do not know what the inciting event is in MS that would be the equivalent of immunizing an animal with neural antigen. Despite this, R-EAE has and should continue to provide experimental data of considerable importance to an understanding of the mechanisms involved in the evolution of inflammatory demyelination. Other important models of MS utilize viral-induced demyelination. Although the clinical picture of most of the chronic demyelinating viral infections does not show as clear a relapsing or remitting pattern as seen in R-EAE, viral etiologies better fit the epidemiology of MS [16]. Several studies have demonstrated development of an acute EAE-like disease with sensitization to neural antigens following viral infection [12, 30, 56]. Thus, one can hypothesize an initial viral illness causing sensitization of the host to a neural antigen (?MBP) with a subsequent immunopathogenic course similar to that seen in R-EAE. Whether this will in fact be the case remains unproven as yet. Our understanding of the immunopathogenic mechanisms underlying inflammatory demyelination has been enlarged through studies of R-EAE. It is now clear that the minimal myelin antigen necessary for production of the disease is MBP, although this may differ in some species. The relapsing nature of this disorder is mediated in part through lymphocytes, as demonstrated in transfer studies, and thus does not require persistent antigenic depots. There is a genetic susceptibility to development of the CNS autoimmune state, and we speculate that an as yet unidentified perturbation of the host immune system allows for the occurrence of relapsing disease (Table 3).
Mice immunized to produce relapsing experimental allergic encephalomyelitis (R-EAE) were treated with immunomodulating agents known to affect acute monophasic experimental allergic encephalomyelitis. Pretreatment with either mouse spinal cord or myelin basic protein in incomplete Freund's adjuvant decreased the incidence of R-EAE from 77% to 28 and 31%, respectively. Single doses of cyclophosphamide (CY) at the time of immunization did not affect development of R-EAE. CY given repetitively in low doses decreased the incidence of R-EAE to 10%. Therefore, R-EAE can be altered by immunomodulation, but the patterns differ from those seen in acute EAE.