Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0014070 (encephalomyelitis)
 13,017 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Rat T cells, like those of mouse and human origin, respond strongly to superantigens (SAg) derived from Staphylococcus aureus enterotoxins A and B (SEA, SEB). Lewis and ACI are high responders, whereas Brown Norway (BN) is a low responder. Congenic and back-cross rat studies indicate that the degree of responsiveness is controlled by at least one non-MHC gene. The action of these genes may reside in the antigen-presenting cells (APC), since both Sephadex G10 non-adherent BN spleen cells and purified BN T cells in the presence of Lewis APC can respond well to SE. Responses to concanavalin A (Con A) and SEA generally segregate together in back-cross rats. Surprisingly, the degree of responsiveness to Con A and SEA is not correlated with the susceptibility to experimental allergic encephalomyelitis (EAE) either in independently derived inbred rat strains or in (Lewis x BN) x BN back-cross rats.
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PMID:Genetic control of rat T-cell response to Staphylococcus aureus enterotoxins (SE). 176 96

Superantigens have been suggested to act as powerful TCR V beta-specific inducers of T cell reactivity in autoimmune diseases. We have investigated the capacity of staphylococcal enterotoxins (SE) to prime autoreactive T cell responses in naive animals in the Lewis rat model of experimental autoimmune encephalomyelitis (EAE), where myelin basic protein (MBP)-specific CD4+ effector T cells express almost exclusively V beta 8.2 TCR elements. By taking advantage of the reactivity of V beta 8.2+ MBP-specific T cells to SEE but not to other SEs in vitro, we estimated the potential of different SEs (SEA, SEB, and SEE) to induce a primary T cell response to soluble MBP in vivo. Upon immunization of naive rats with soluble MBP alone or MBP and SEB (which is only a very weak superantigen for rat T cells), no MBP-responses could be retrieved. Similarly, when coimmunizing naive rats with MBP and V beta 8.2-activating SEE, no autoreactivity was inducible. By contrast, coimmunization of animals with soluble MBP and the superantigen SEA that is strongly activating various T cell subpopulations in Lewis rats but not V beta 8.2+ (i.e., potentially MBP reactive) T cells led to a significant primary MBP-specific T cell autoreactivity. These SEA-induced MBP-reactive T cells expressed V beta 8.2 TCRs at levels similar to those seen in autoreactive T cells conventionally induced by immunization with MBP administered in complete Freund's adjuvant (CFA) and could induce disease in a transfer model of EAE. Thus, our results are consistent with the notion that superantigens are able to induce primary T cell responses to soluble autoantigens by a non-V beta specific mechanism of bystander priming.
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PMID:Superantigens induce primary T cell responses to soluble autoantigens by a non-V beta-specific mechanism of bystander activation. 753 95

Staphylococcal enterotoxins (SEs) can bind major histocompatibility antigens and stimulate T cells which bear particular types of T cell receptor. Therefore, it has been postulated that SEs may trigger or modulate the development of autoimmune diseases caused by T cells. In the present study, we examined the effects of SEs on rat encephalitogenic T cells and the clinical manifestation of experimental autoimmune encephalomyelitis (EAE). SED, but not other SEs, stimulated encephalitogenic T cells. Furthermore, culture of lymphoid cells from myelin basic protein (MBP)-immunized rats with SED augmented the clinical manifestation of passively transferred EAE, whereas SEA and SEB showed no significant EAE-transfer ability. Flow cytometric analysis demonstrated that in vitro SED stimulation of T cells from MBP-immunized rats, but not from normal rats, resulted in selective expansion of V beta 8.2+ T cells. Consistent with in vitro findings, in vivo administration of SED modulated EAE elicited by immunization with MBP. SED given after the immunization augmented clinical manifestation, especially at low doses. On the other hand, SED given 7 days before the immunization suppressed the development of EAE in a dose-dependent manner. Interestingly, the same toxin given at a dose of 20 micrograms to thymectomized rats induced enhanced EAE regardless of the timing of administration. It has already been established that SEs stimulate T cells bearing a particular type of TCR V beta chain and subsequently induce unresponsiveness of these T cells. The present results suggest that a similar mechanism may operate in rats after the toxin treatment and MBP immunization. However, in vitro assay showed that the proliferative responses of T cells from EAE-suppressed rats to MBP and SED were not eliminated, suggesting that SED-induced suppressor T cells may also play some roles in EAE suppression. The present study has shown that SED, one of the superantigens, modulates an autoimmune disease. More importantly, its effects are not uniform, but instead are closely related to the dose of the toxin, timing of toxin exposure, and the status of hosts.
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PMID:Immunomodulation of experimental autoimmune encephalomyelitis by staphylococcal enterotoxin D. 768 98

Staphylococcal enterotoxins (SEs) are one member of a unique group of molecules known as superantigens. They are potent T-cell activators and stimulate a large number of T cells bearing specific T-cell-receptor beta-chain variable regions. It has been proposed that superantigens may trigger autoimmune disorders by stimulation of autoreactive T cells with restricted beta-chain variable-chain usage. We investigated the effects of SEs B and A (SEB and SEA) on the reactivation of experimental allergic encephalomyelitis, an animal model for multiple sclerosis. We report that SEB can reinduce encephalitis multiple times in PL/J mice that had previously recovered from an acute episode. SEB was also able to induce encephalitis in mice previously immunized with myelin basic protein but did not show clinical signs of disease. In addition, it was observed that T cells from PL/J mice that had been previously activated by myelin basic protein in complete Freund's adjuvant or in complete Freund's adjuvant alone were resistant to the induction of anergy by SEB. To determine whether reactivation of experimental allergic encephalomyelitis was specific for SEB, another superantigen, SEA, was employed. It was found that SEA was also able to reinduce experimental allergic encephalomyelitis in mice previously recovered from an acute episode and those that had been previously immunized with myelin basic protein but did not show clinical signs of disease. These results indicate that SEs are capable of reactivating autoreactive T cells and inducing autoimmune disease.
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PMID:Staphylococcal enterotoxins can reactivate experimental allergic encephalomyelitis. 837 29

Recent evidence indicates that chronic autoimmune disease can result from breakdown of regulation and subsequent activation of self-reactive T cells. In many murine autoimmune disease systems and in the Lewis rat, antigen-specific T cells utilizing the T cell receptor (TCR) Vbeta8.2 gene segment play a major role. In the myelin basic protein-induced experimental autoimmune encephalomyelitis (EAE) model in H-2(u) mice, we had shown that T cells recognizing a peptide determinant within the framework 3 region of the Vbeta8.2 chain have a critical role in influencing the course of the disease. Here, we report experiments in another disease system, collagen II (CII)-induced arthritis (CIA) in DBA/1LacJ (H-2(q)) mice, indicating a remarkably parallel control circuit to that found for EAE. A critical role is played by CII-specific Vbeta8.2-bearing T cells in the CIA system, which we have confirmed. Animals treated with the superantigen SEB before CII administration are significantly protected from CIA. Next, we tested the ability of peptides encompassing the entire Vbeta8.2 chain to induce proliferative responses. Only TCR peptide B5 (amino acids 76-101), a regulatory peptide in EAE, induced proliferation. B5 was then used to vaccinate DBA/1LacJ mice and was shown to reduce greatly the severity and incidence of CIA as measured by joint inflammation or histology. Furthermore, similar protection was found when B5 was administered after CII immunization. It was shown that there is physiological induction of a proliferative response to B5 during CIA and that the determinant within B5 is produced from a single chain TCR construct containing the entire Vbeta8.2 chain. Finally, the regulation of CIA is discussed in the context of other experimental autoimmune diseases, especially EAE, with emphasis on what appear to be strikingly common mechanisms.
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PMID:Regulatory T cells specific for the same framework 3 region of the Vbeta8.2 chain are involved in the control of collagen II-induced arthritis and experimental autoimmune encephalomyelitis. 915 97

Immunization of (PL/J x SJL/J)F1 mice with myelin basic protein (MBP) induces relapsing experimental autoimmune encephalomyelitis (EAE). Relapses occur 7 to 10 days after recovery from the initial paralysis. Staphylococcal enterotoxins (SE) A or B, administered after recovery from the initial paralysis, induce immediate relapses. IL-12 is involved in the induction of EAE. Here, we show that SEA and SEB induce IL-12 in splenocytes from (PL/J x SJL/J)F1 mice in vitro and increase the level of IL-12 in the sera of mice treated with these superantigens. IL-12 administration mimics SE in inducing spontaneous relapses and in enhancing the severity and frequency of spontaneous relapses. IL-12 neutralization blocks SE-induced and subsequent relapses of EAE, and, when instituted after recovery from the initial attack, prevents spontaneous relapse. This is the first report of prevention of relapses of EAE with anti-IL-12 Ab, an approach which may prove useful in the prevention of exacerbations in multiple sclerosis.
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PMID:Antibodies against IL-12 prevent superantigen-induced and spontaneous relapses of experimental autoimmune encephalomyelitis. 979 48

The staphylococcal enterotoxin superantigens are among the most potent T cell stimulators known. They have been shown to alter the course of disease in experimental allergic encephalomyelitis, an animal model for multiple sclerosis (MS). We have previously demonstrated that two of the staphylococcal enterotoxins, SEA and SEB, are able to reactivate paralysis in PL/J mice which had been immunized with myelin basic protein (MBP) and resolved an initial episode of paralysis. In PL/J mice, Ac1-11 is the dominant encephalitogenic determinant of MBP. We hypothesized that superantigen reactivation of experimental allergic encephalomyelitis (EAE) may result in the spreading of T cell specificities for other epitopes of MBP. PL/J mice which had resolved an initial episode of EAE were treated with SEA and developed a second episode of paralysis. At the onset of symptoms, mice were sacrificed and splenocytes were stimulated in vitro with a panel of MBP peptides. EAE reactivation by SEA resulted in the spreading of T cell specificites to residues 100 to 120 of MBP. While intramolecular spreading did occur, spreading to other antigens did not, as evidenced by the lack of response to a proteolipid protein (PLP) peptide and heat shock protein 60 (hsp 60). To further characterize the epitope MBP 100-120, PL/J mice were immunized with MBP 100-120. No initial development of disease was observed. However, administration of SEA 2 weeks after MBP 100-120 immunization resulted in the onset of paralysis. In addition to a proliferative response to MBP 100-120, these mice also exhibited a proliferative response to the flanking MBP peptides 81-100 and 120-140. Thus, SEA is able to induce intramolecular epitope spreading in PL/J mice after reactivation of EAE.
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PMID:Intramolecular epitope spreading induced by staphylococcal enterotoxin superantigen reactivation of experimental allergic encephalomyelitis. 1188 Jan 46