Thyroid hormone and thyromimetics inhibit myelin and axonal degeneration and oligodendrocyte loss in EAE.

We have previously demonstrated that thyromimetics stimulate oligodendrocyte precursor cell differentiation and promote remyelination in murine demyelination models. We investigated whether a thyroid receptor-beta selective thyromimetic, sobetirome (Sob), and its CNS-targeted prodrug, Sob-AM2, could prevent myelin and axonal degeneration in experimental autoimmune encephalomyelitis (EAE). Compared to controls, EAE mice receiving triiodothyronine (T3, 0.4 mg/kg), Sob (5 mg/kg) or Sob-AM2 (5 mg/kg) had reduced clinical disease and, within the spinal cord, less tissue damage, more normally myelinated axons, fewer degenerating axons and more oligodendrocytes. T3 and Sob also protected cultured oligodendrocytes against cell death. Thyromimetics thus might protect against oligodendrocyte death, demyelination and axonal degeneration as well as stimulate remyelination in multiple sclerosis.

Clinical trial of a formal group fatigue program in multiple sclerosis.

Fatigue: Take Control is a novel program to teach fatigue management to people with multiple sclerosis (MS) following recommendations in the Fatigue and Multiple Sclerosis guideline. Fatigue: Take Control includes six 2-hour group sessions with DVD viewing, discussion and homework and accompanying participant and leader workbooks. While many people have participated in Fatigue: Take Control programs, its efficacy has not been determined. The objective of this study was to determine whether participation in Fatigue: Take Control reduces fatigue and increases self-efficacy in people with MS. Thirty participants were randomly assigned to a group who immediately participated in the program (FTC) or a wait-list group (WL). The primary outcome was the Modified Fatigue Impact Scale (MFIS) and secondary outcomes were the Multiple Sclerosis Self-Efficacy Scale (MSSE) and the Fatigue Severity Scale (FSS). The MFIS was administered on 10 occasions. Other measures were administered on four occasions. A mixed model tested the effects using all observations. Compared with the WL, the FTC group had significantly more improvement on the MFIS [F(1, 269) = 7.079, p = 0.008] and the MSSE [F(1, 111) = 5.636, p = 0.019]. No significant effect was found for the FSS. Across all visits, fatigue was significantly lower and self-efficacy was significantly higher for the FTC group compared with the WL group. This pilot study demonstrated significant effects in fatigue and self-efficacy among subjects taking the Fatigue: Take Control program, suggesting that this comprehensive program based on the Fatigue and Multiple Sclerosis guideline may be beneficial in MS.

Lipoic acid stimulates cAMP production in T lymphocytes and NK cells.

The anti-oxidant lipoic acid (LA) potently suppresses clinical and pathologic disease in the animal model of multiple sclerosis, experimental autoimmune encephalomyelitis, by inhibiting the migration of pathogenic T cells to the spinal cord. The mechanism by which this occurs is largely unknown. In this report we demonstrate that LA induces increases in cyclic AMP, a known immunosuppressant, in human T cells. The increase in cAMP is associated with increased adenylyl cyclase activity and is partially blocked by prostanoid receptor antagonists. We present evidence that LA also stimulates cAMP production in natural killer (NK) cells. This novel mechanism of action is highly relevant to the immunomodulatory effects of LA and provides further support for the study of LA as a therapeutic agent for multiple sclerosis and other autoimmune diseases.

A highly immunogenic trivalent T cell receptor peptide vaccine for multiple sclerosis.

BACKGROUND: T cell receptor (TCR) peptide vaccination is a novel approach to treating multiple sclerosis (MS). The low immunogenicity of previous vaccines has hindered the development of TCR peptide vaccination for MS. OBJECTIVE: To compare the immunogenicity of intramuscular injections of TCR BV5S2, BV6S5 and BV13S1 CDR2 peptides in incomplete Freunds adjuvant (IFA) with intradermal injections of the same peptides without IFA. METHODS: MS subjects were randomized to receive TCR peptides/IFA, TCR peptides/saline or IFA alone. Subjects were on study for 24 weeks. RESULTS: The TCR peptides/IFA vaccine induced vigorous T cell responses in 100% of subjects completing the 24-week study (9/9) compared with only 20% (2/10) of those receiving the TCR peptides/saline vaccine (P =0.001). IFA alone induced a weak response in only one of five subjects. Aside from injection site reactions, there were no significant adverse events attributable to the treatment. CONCLUSIONS: The trivalent TCR peptide in IFA vaccine represents a significant improvement in immunogenicity over previous TCR peptide vaccines and warrants investigation of its ability to treat MS.

Rudimentary TCR signaling triggers default IL-10 secretion by human Th1 cells.

Understanding the process of inducing T cell activation has been hampered by the complex interactions between APC and inflammatory Th1 cells. To dissociate Ag-specific signaling through the TCR from costimulatory signaling, rTCR ligands (RTL) containing the alpha1 and beta1 domains of HLA-DR2b (DRA*0101:DRB1*1501) covalently linked with either the myelin basic protein peptide 85-99 (RTL303) or CABL-b3a2 (RTL311) peptides were constructed to provide a minimal ligand for peptide-specific TCRs. When incubated with peptide-specific Th1 cell clones in the absence of APC or costimulatory molecules, only the cognate RTL induced partial activation through the TCR. This partial activation included rapid TCR zeta-chain phosphorylation, calcium mobilization, and reduced extracellular signal-related kinase activity, as well as IL-10 production, but not proliferation or other obvious phenotypic changes. On restimulation with APC/peptide, the RTL-pretreated Th1 clones had reduced proliferation and secreted less IFN-gamma; IL-10 production persisted. These findings reveal for the first time the rudimentary signaling pattern delivered by initial engagement of the external TCR interface, which is further supplemented by coactivation molecules. Activation with RTLs provides a novel strategy for generating autoantigen-specific bystander suppression useful for treatment of complex autoimmune diseases.

T lymphocytes promote the development of bone marrow-derived APC in the central nervous system.

Certain cells within the CNS, microglial cells and perivascular macrophages, develop from hemopoietic myelomonocytic lineage progenitors in the bone marrow (BM). Such BM-derived cells function as CNS APC during the development of T cell-mediated paralytic inflammation in diseases such as experimental autoimmune encephalomyelitis and multiple sclerosis. We used a novel, interspecies, rat-into-mouse T cell and/or BM cell-transfer method to examine the development and function of BM-derived APC in the CNS. Activated rat T cells, specific for either myelin or nonmyelin Ag, entered the SCID mouse CNS within 3-5 days of cell transfer and caused an accelerated recruitment of BM-derived APC into the CNS. Rat APC in the mouse CNS developed from transferred rat BM within an 8-day period and were entirely sufficient for induction of CNS inflammation and paralysis mediated by myelin-specific rat T cells. The results demonstrate that T cells modulate the development of BM-derived CNS APC in an Ag-independent fashion. This previously unrecognized regulatory pathway, governing the presence of functional APC in the CNS, may be relevant to pathogenesis in experimental autoimmune encephalomyelitis, multiple sclerosis, and/or other CNS diseases involving myelomonocytic lineage cells.

Symptom factor analysis, clinical findings, and functional status in a population-based case control study of Gulf War unexplained illness.

Few epidemiological studies have been conducted that have incorporated clinical evaluations of Gulf War veterans with unexplained health symptoms and healthy controls. We conducted a mail survey of 2022 Gulf War veterans residing in the northwest United States and clinical examinations on a subset of 443 responders who seemed to have unexplained health symptoms or were healthy. Few clinical differences were found between cases and controls. The most frequent unexplained symptoms were cognitive/psychological, but significant overlap existed with musculoskeletal and fatigue symptoms. Over half of the veterans with unexplained musculoskeletal pain met the criteria for fibromyalgia, and a significant portion of the veterans with unexplained fatigue met the criteria for chronic fatigue syndrome. Similarities were found in the clinical interpretation of unexplained illness in this population and statistical factor analysis performed by this study group and others.

Neuropsychological effects of interferon beta-1a in relapsing multiple sclerosis. Multiple Sclerosis Collaborative Research Group.

Cognitive dysfunction is common in multiple sclerosis (MS), yet few studies have examined effects of treatment on neuropsychological (NP) performance. To evaluate the effects of interferon beta-1a (IFNbeta-1a, 30 microg administered intramuscularly once weekly [Avonex]) on cognitive function, a Comprehensive NP Battery was administered at baseline and week 104 to relapsing MS patients in the phase III study, 166 of whom completed both assessments. A Brief NP Battery was also administered at 6-month intervals. The primary NP outcome measure was 2-year change on the Comprehensive NP Battery, grouped into domains of information processing and learning/memory (set A), visuospatial abilities and problem solving (set B), and verbal abilities and attention span (set C). NP effects were most pronounced in cognitive domains vulnerable to MS: IFNbeta-1a had a significant beneficial effect on the set A composite, with a favorable trend evident on set B. Secondary outcome analyses revealed significant between-group differences in slopes for Brief NP Battery performance and time to sustained deterioration in a Paced Auditory Serial Addition Test processing rate, favoring the IFNbeta-1a group. These results support and extend previous observations of significant beneficial effects of IFNbeta-1a for relapsing MS.

Differential susceptibility of human T(h)1 versus T(h) 2 cells to induction of anergy and apoptosis by ECDI/antigen-coupled antigen-presenting cells.

Antigen-coupled antigen-presenting cells (APC) serve as potent tolerogens for inhibiting immune responses in vivo and in vitro, apparently by providing an antigen-specific signal through the TCR in the absence of co-stimulation. Although this approach has been well studied in rodents, little is known about its effects on human T cells. We evaluated the specificity and mechanisms of tolerization of human T cells in vitro using monocyte-enriched adherent cells that were pulsed with antigen and treated with the cross-linker, 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (ECDI). Autologous antigen-coupled APC selectively tolerized T cells of the T(h)1 but not T(h)2 lineage through a mechanism that involved both antigen-specific and antigen-non-specific elements. The tolerization process was dependent on the ECDI and antigen concentration, and the coupling time, and was reflected by initial up-regulation of CD25. However, upon re-stimulation with fresh APC and antigen, tolerized T(h)1 cells failed to proliferate or to produce T(h)1 cytokine message or secreted protein, had decreased expression of CD25, CD28 and B7 and increased expression of MHC class II molecules, and demonstrated an enhanced commitment to apoptosis. T(h)1 cell tolerization could be prevented by adding anti-CD28 antibody, IL-2 or untreated APC at the same time as the ECDI/antigen-coupled APC, or reversed by adding anti-CD28 antibody or IL-2 upon re-stimulation with fresh APC plus antigen. Thus, the tolerizing effect of ECDI/antigen-coupled APC on human T(h)1 cells appears to involve a reversible anergy mechanism leading to apoptosis, whereby the targeted T cells receive full or partial activation through the TCR, without coordinate co-stimulation. These data suggest dichotomous signaling requirements for inactivating cells of the T(h)1 and T(h)2 lineages that may have important implications for treatment of T(h)1-mediated autoimmune or inflammatory diseases.

Gulf War unexplained illnesses: persistence and unexplained nature of self-reported symptoms.

Most published reports of health symptoms among Gulf War (GW) veterans have been based on self-reported questionnaire data. The presence of these symptoms at the time of a clinical evaluation and the unexplained nature of the symptoms have not been described. We report the findings of a sample of symptomatic veterans that were examined as part of a population-based case-control study of GW unexplained illnesses. Participants in the case-control study were selected from responders to a cross-sectional survey of a random sample of GW veterans residing in the northwestern United States. The initial survey questionnaire solicited information on the presence of fatigue and psychological/cognitive, gastrointestinal, musculoskeletal, and dermatological problems. The persistence of the symptoms and possible explanatory diagnoses were explored at the time of the clinical evaluation. Findings from the first 225 participants who completed clinical examinations indicate significant differences between self-reported symptoms on the survey questionnaire and those confirmed at the time of clinical exam. The agreement between symptoms reported both on the survey and at the time of examination varies across the symptom groups. While self-reported unexplained fatigue was confirmed at the time of clinical encounter in 79% of participants, self-reported gastrointestinal symptoms were confirmed at the clinical encounter in only 20% of participants. Differences between symptoms reported on the survey questionnaire and those confirmed at the time of clinical encounter were attributable to finding a clinical diagnosis for the symptom, resolution of symptom(s) between time of questionnaire and clinical exam, and inadvertent endorsement of the symptom on the questionnaire. These findings suggest that due to the possibility of outcome misclassification, inappropriate conclusions may be drawn about the association between exposures and unexplained illnesses in GW veterans from data derived solely from self-administered questionnaires.

Design, engineering and production of functional single-chain T cell receptor ligands.

Major histocompatibility complex (MHC) class II molecules are membrane-anchored heterodimers on the surface of antigen presenting cells (APCs) that bind the T cell receptor, initiating a cascade of interactions that results in antigen-specific activation of clonal populations of T cells. The peptide binding/T cell recognition domains of rat MHC class II (alpha-1 and beta-1 domains) were expressed as a single exon for structural and functional characterization. These recombinant single-chain T cell receptor ligands (termed 'beta1alpha1' molecules) of approximately 200 amino acid residues were designed using the structural backbone of MHC class II molecules as template, and have been produced in Escherichia coli with and without N-terminal extensions containing antigenic peptides. Structural characterization using circular dichroism predicted that these molecules retained the antiparallel beta-sheet platform and antiparallel alpha-helices observed in the native MHC class II heterodimer. The proteins exhibited a cooperative two-state thermal folding-unfolding transition. Beta1alpha1 molecules with a covalently linked MBP-72-89 peptide showed increased stability to thermal unfolding relative to the empty beta1alpha1 molecules. This new class of small soluble polypeptide provides a template for designing and refining human homologues useful in detecting and regulating pathogenic T cells.

Cerebrospinal fluid abnormalities in a phase III trial of Avonex (IFNbeta-1a) for relapsing multiple sclerosis. The Multiple Sclerosis Collaborative Research Group.

BACKGROUND AND OBJECTIVE: This report provides results of CSF analyses done in a subset of relapsing remitting MS patients participating in a placebo-controlled, double-blind, phase III clinical trial of IFNbeta-Studies supported by the National Multiple Sclerosis Society (grants RG2019, RG2827),a (Avonex , Biogen). The clinical trial demonstrated that IFNbeta-1a treatment resulted in significantly reduced disability progression, annual relapse rate, and new brain lesions visualized by cranial magnetic resonance imaging. The objectives of the current study were to determine: (a) whether CSF abnormalities in MS patients correlated with disease or MRI characteristics, and (b) effects of IFNbeta-1a therapy on these CSF abnormalities. METHODS: CSF was analyzed from 262 (87%) of the 301 study subjects at entry into the clinical trial, and a second CSF sample was analyzed from 137 of these 262 subjects after 2 years of therapy. CSF cell counts, oligoclonal bands (OCB), IgG index, and free kappa light chains were measured using standard assays. Baseline CSF results were compared with demographic, disease, and MRI parameters. Differences in on-study relapse rate, gadolinium enhancement, and EDSS change according to baseline CSF status was used to determine the predictive value of CSF for subsequent clinical and MRI disease activity. Change in CSF parameters after 104 weeks were used to determine the effects of treatment. RESULTS: (1) At study baseline, 37% of the subjects had abnormal CSF WBC counts, 61% had abnormal levels of CSF free kappa light chains, 84% had abnormal IgG index values, and 90% were positive for OCB. (2) Baseline IgG index, kappa light chains, and OCB showed weakly positive, statistically significant correlations with Gd-enhanced lesion volume and T2 lesion volume. WBC showed a statistically significant correlation with Gd-enhancing lesion volume but was uncorrelated with T2 lesion volume. (3) There was an associated between baseline CSF WBC counts and on-study clinical and MRI disease activity in placebo recipients. (4) IFNbeta-1a treatment resulted in significantly reduced CSF WBC counts, but there was no treatment-related change in CSF IgG index, kappa light chains, or OCB, which remained relatively stable over time in both patient groups. CONCLUSIONS: The current study documents significant reductions in CSF WBC counts in patients treated with IFNbeta-1a for 104 weeks. This finding is considered relevant to the therapeutic response, since CSF WBC counts were found to be positively correlated with subsequent clinical and MRI disease activity in placebo-treated relapsing MS patients.

Myelin basic protein-specific T lymphocytes induce chronic relapsing experimental autoimmune encephalomyelitis in lymphocyte-deficient (SCID) mice.

Myelin basic protein (BP)-specific T lymphocyte cell lines were selected from the lymph nodes (LN) of BP-immunized, H-2d, CXJ-1 mice prior to the onset of clinical disease. These CD4+ T cells induced severe acute experimental autoimmune encephalomyelitis (EAE) in MHC-compatible (H-2d), lymphocyte-deficient (SCID) mice (C.B-17scid/scid). The incidence of disease was much higher in immunodeficient SCID mice (71%) than in syngeneic immunocompetent CXJ-1 mice (5%). SCID mice with EAE had an acute progressive paralytic disease with inflammation and myelin loss detected in the spinal cord. Eighty-six percent (12/14) of mice followed for more than 2 weeks had 1 or more relapses of EAE. These results demonstrate that clinical remission and relapse of EAE can be induced by the single adoptive transfer of a LN-derived BP-specific T cell line in the absence of host-derived effector and regulatory lymphocytes. Furthermore, the data demonstrate that the pathogenic potential of BP-specific T cells is greater in lymphocyte-deficient SCID mice compared with immunocompetent mice, suggesting that autoreactive T cells are controlled by potent inhibitory mechanisms associated with regulatory lymphocytes. These results are relevant to mechanisms of disease remission and relapse mediated by lymphocytes involved in paralytic inflammatory diseases such as multiple sclerosis (MS).

IL-7 enhances Ag-specific human T cell response by increasing expression of IL-2R alpha and gamma chains.

Interleukin-7 has demonstrated potent enhancing effects on the growth and differentiation of several immature cell types, including thymocytes, and on survival of resting and antigen activated T cells. In this study, we evaluated the effects of IL-7 on post-thymic antigen-specific T cells from human blood. IL-7 was found to enhance proliferation responses and IFN-gamma secretion of myelin or recall Ag-specific Th1 cells through the selective up-regulation of the IL-2Ralpha and gamma but not beta chains in both an Ag-dependent and Ag-independent manner, but did not affect monocytes, B cells, or NK cells. These functions of IL-7 enhanced the detection of Th1 but not Th2 cell frequency by >2.5 fold, and promoted selection of Ag-specific Th1 cells by the limiting dilution method. Moreover, IL-7 pretreatment conferred increased resistance of CD4+ T cells to CD8+ cell lysis. These studies demonstrate that IL-7 promotes the growth and survival of circulating Ag-specific human Th1 cells through a mechanism that probably involves the gammac common receptor for IL-2 family members that includes IL-7.

Simplified method of identifying severe combined immunodeficient (SCID) mice versus non-SCID mice by flow cytometric analysis of peripheral blood.

Several studies have utilized simple breeding strategies to create new immunodeficient mouse strains from severe combined immunodeficient (SCID) mice and non-SCID mice with secondary traits in order to evaluate the involvement of lymphocytes and immune responses in a variety of processes. We utilized a breeding strategy with C.B-17scid/scid (SCID) (H-2d) mice and SJL (H-2s) mice to generate immunodeficient mice that were histocompatible with the inbred SJL strain (H-2s) in order to evaluate the role of histocompatible recipient lymphocytes in adoptively transferred autoimmune disease mediated by SJL T lymphocytes. [SCID x SJL]F1 mice (heterozygous for H-2 loci and heterozygous for the SCID mutation) were backcrossed with SCID mice and the resulting offspring expressed a variety of phenotypes, including SCID or non-SCID and H-2s/H-2d or H-2d/H-2d. In order to screen offspring for the desired phenotype (SCID, H-2s), a flow cytometric method utilizing forward- and side-scatter parameters of peripheral blood cells was used to distinguish SCID from non-SCID animals. This method simplified the screening process and was as reliable as anti-CD3 fluorescent monoclonal antibody staining for detecting the presence (non-SCID) or absence (SCID) of T lymphocytes in peripheral blood.

Immunity to T cell receptor peptides in multiple sclerosis. III. Preferential immunogenicity of complementarity-determining region 2 peptides from disease-associated T cell receptor BV genes.

Vaccination with synthetic TCR peptides from the BV5S2 complementarity-determining region 2 (CDR2) can boost significantly the frequency of circulating CD4+ peptide-specific Th2 cells in multiple sclerosis (MS) patients, with an associated decrease in the frequency of myelin basic protein (MBP)-reactive Th1 cells and possible clinical benefit. To evaluate the immunogenicity of CDR2 vs other regions of the TCR, we vaccinated seven MS patients with overlapping BV5S2 peptides spanning amino acids 1-94. Six patients responded to at least one of three overlapping or substituted CDR2 peptides possessing a core epitope of residues 44-52, and one patient also responded to a CDR1 peptide. Of the CDR2 peptides, the substituted (Y49T)BV5S2-38-58 peptide was the most immunogenic but cross-reacted with the native sequence and had the strongest binding affinity for MS-associated HLA-DR2 alleles, suggesting that position 49 is an MHC rather than a TCR contact residue. Two MS patients who did not respond to BV5S2 peptides were immunized successfully with CDR2 peptides from different BV gene families overexpressed by their MBP-specific T cells. Taken together, these results suggest that a widely active vaccine for MS might well involve a limited set of slightly modified CDR2 peptides from BV genes involved in T cell recognition of MBP.

Effects of vaccination with T cell receptor peptides: epitope switching to a possible disease-protective determinant of myelin basic protein that is cross-reactive with a TCR BV peptide.

Immunization of Lewis rats with guinea-pig myelin basic protein (Gp-MBP) induced T cell responses to primary and secondary encephalitogenic determinants, as well as to a third non-encephalitogenic epitope, residues 55-69. This sequence is of interest due to its protective activity against experimental autoimmune encephalomyelitis. Protection involved induction of MBP-55-69-specific T cells expressing cross-reactive TCR BV8S6 genes that activated regulatory T cells specific for TCR BV8S2 determinants expressed on encephalitogenic T cells. We here present and discuss new evidence suggesting a possible immunological cross-reactivity between the protective Gp-MBP-55-69 peptide and the regulatory BV8S2-39-59 peptide. This cross-reactivity, which may also occur between the human MBP-55-74 peptide and the BV12S2-38-58 sequence, has potentially important implications for human diseases such as multiple sclerosis.

Magnetic resonance studies of intramuscular interferon beta-1a for relapsing multiple sclerosis. The Multiple Sclerosis Collaborative Research Group.

The Multiple Sclerosis Collaborative Research Group trial was a double-blind, randomized, multicenter, phase III, placebo-controlled study of interferon beta-1a (IFNbeta-1a; AVONEX) in relapsing forms of multiple sclerosis. Initial magnetic resonance imaging results have been published; this report provides additional results. Treatment with IFNbeta-1a, 30 microg once weekly by intramuscular injection, resulted in a significant decrease in the number of new, enlarging, and new plus enlarging T2 lesions over 2 years. The median increase in T2 lesion volume in placebo and IFNbeta-1a patients was 455 and 152 mm3, respectively, at 1 year and 1,410 and 628 mm3 at 2 years, although the treatment group differences did not reach statistical significance. For active patients, defined as those with gadolinium enhancement at baseline, the median change in T2 lesion volume in placebo and IFNbeta-1a patients was 1,578 and -12 mm3 and 2,980 and 1,285 mm3 at 1 and 2 years, respectively. Except for a minimal correlation of 0.30 between relapse rate and the number of gadolinium-enhanced lesions, correlations between MR and clinical measures at baseline and throughout the study were in general poor. Once weekly intramuscular IFNbeta-1a appears to impede the development of multiple sclerosis lesions at an early stage and has a favorable impact on the long-term sequelae of these inflammatory events as indicated by the slowed accumulation of T2 lesions.