Department of Immunology, Weizmann Institute of Science, Rehovot, Israel and Department of Medicine B, Beilinson Medical Center, Petach Tiqva, Israel
felix.mor@weizmann.ac.il
MD Hebrew University Jerusalem 1980 Internal Medicine 1988 PhD Weizmann Institute 1995 Associate Professor, Internal Medicine, Sackler Faculty of Medicine 2004
Abstract: Accumulating evidence suggests that autoimmunity against neuronal proteins is important for MS pathogenesis. We have characterized T- and B-cell responses associated with experimental autoimmune encephalomyelitis (EAE) induced in Lewis rats with recombinant beta-Synuclein (betaSync), a neuronal component. The encephalitogenic betaSync-specific T cells recognize a single immunodominant region with an epitope delineated at amino acids 97-105; B-cell specificity is more widespread, albeit directed mostly to the C-terminus of betaSync. Most interestingly, betaSync-induced autoimmune T- and B-cell responses spread not only to other neuronal antigens but also to myelin encephalitogens, raising the possibility that anti-neuronal immune attacks could also result in demyelination.
Abstract: The 60 kDa heat shock protein (HSP60) has been reported to influence T-cell responses in two ways: as a ligand of toll-like receptor 2 signalling and as an antigen. Here we describe a new mechanism of T-cell immuno-regulation focused on HSP60: HSP60 is up-regulated and presented by activated T cells (HSP60 is an ergotope) to regulatory (anti-ergotypic) T cells. Presentation of HSP60 by activated T cells was found to be MHC-restricted and dependent on accessory molecules - CD28, CD80 and CD86. Anti-ergotypic T cells responded to T-cell HSP60 by proliferation and secreted IFNgamma and TGFbeta1. In vitro, the anti-ergotypic T cells inhibited IFNgamma production by their activated T-cell targets. In vivo, adoptive transfer of an anti-ergotypic HSP60-specific T-cell line led to decreased secretion of IFNgamma by arthritogenic T cells and ameliorated adjuvant arthritis (AA). Thus, the presentation of HSP60 by activated T cells turns them into targets for anti-ergotypic regulatory T cells specific for HSP60. However, the direct interaction between the anti-ergotypic T regulators (anti-HSP60) and the activated T cells also down-regulated the regulators. Thus, by functioning as an ergotope, HSP60 can control both the effector T cells and the regulatory HSP60-specific T cells that control them.
Abstract: Current treatment of human autoimmune diseases (AIDs) was developed empirically and relies mostly on non-selective suppression of the immune system. Traditional non-selective immunosuppressants such as corticosteroids, cyclophosphamide, and methotrexate and more novel means such as monoclonal antibodies to CD3, CD4, or CD25 do not discriminate between pathogenic and beneficial T cells. Importantly, the severe side effects seen with current therapies are related to the fact that these treatments not only suppress the pathogenic disease-inducing cells, but also cells influential in combating infections and killing malignant cells. Severe infections and malignancies are the inevitable result of non-selective immune suppression. Many of the novel forms of therapy of AID were developed in experimental animals, and their translation to the human disease was associated with the revelation of unexpected and sometimes catastrophic side effects. These surprises underscore the major differences between the relative simplicity of the experimental model and the complexity of the human disease. How can this current state of treatment of AID be improved? Which principles should guide us in the design of new treatments? This review attempts to offer a new look at these questions.
Abstract: OBJECTIVE: Immunization of rats with alpha-tropomyosin (TPM) led to arthritis, uveitis and dermatitis, typical features of Behçet's disease (BD). The present study characterizes the arthritic features of this animal model, not previously described. METHODS: Lewis rats were immunized with bovine alpha-TPM and another group of rats was treated with neutralizing anti- tumor necrosis factor-alpha (TNF-alpha) antibodies. RESULTS: Clinically more than 90% of the immunized rats developed severe acute arthritis 12 days after vaccination. Rats that were followed-up for 6 months had persistent inflammation of the leg joints. Histologic studies demonstrated predominant mononuclear infiltrations in the acute phase of arthritis; the chronic arthritic process resulted in cartilage and bone damage and abundant fibrosis which led to joint deformations. Male and female rats had a similar clinical course. Analysis of the splenocyte cytokine profile kinetics revealed a persistently high level of interferon-gamma (INF-gamma) and an increase in TNF-alpha secretion during the acute phase. Increasing levels of interleukin (IL)-10 heralded the decline in clinical arthritis. No IL-4 was detected. No arthritis was detected in the rats treated with anti-TNF-alpha antibodies. CONCLUSION: The data indicates that alpha-TPM serves as an autoantigen to induce acute and chronic destructive arthritis in rats. This model is a TNF-alpha dependent autoimmune disease, with a Th1 cytokine profile.
Abstract: Recent work has shown neuro-protective effects of immunization with self-CNS antigens in animal models of Alzheimer's disease, prion diseases and CNS trauma. The major concern with such an approach is the inadvertent induction of autoimmune disease. The present work was initiated to study the incidence of autoimmune disease associated with the induction of T cell autoimmunity to a panel of 70 peptides derived from CNS proteins. Using a MHC class II motif developed in our laboratory to identify candidate peptides, we selected 70 peptides from 40 different CNS proteins. The proteins were selected randomly and represented various biological functions (surface receptors, structural proteins, synaptic proteins, neurodegeneration related proteins). Each peptide was emulsified in CFA and injected to autoimmune-prone Lewis rats. Immunogenicity was verified by peptide-specific LN cell proliferation. In addition, T cell lines were generated for many peptides and tested by adoptive transfer. Except for the previously reported pathogenicity of beta-synuclein, none of the 68 peptides from 39 proteins was found to induce CNS disease in recipient rats. These findings underscore the efficiency of immunological regulation in preventing CNS autoimmune disease, and confirm the uniqueness of the well-known pathogenic CNS auto-antigens.
Abstract: Alzheimer's disease (AD) is a common and devastating neurodegenerative disease. The incidence of AD is increasing in Western societies. The current treatment of AD is mostly symptomatic and ineffective in stopping or reversing the cognitive impairment. One of the exciting and effective new treatments developed in experimental AD is immunization against amyloid-beta peptide. This article provides an overview of immunization therapy in AD and examines the future prospects of this therapeutic modality.
Abstract: We report for the first time a significant increased lymphoproliferative response to alpha tropomyosin as well as observing autoantibodies to tropomyosin observed in Behcet's disease (BD) patients with posterior uveitis. Peripheral blood mononuclear cells (PBMCs) from 18 BD patients with posterior uveitis, 18 patients with other forms of noninfectious uveitis, 9 patients with retinal damage due to photocoagulation as well as 18 healthy donors were evaluated for antigen-specific lymphoproliferative responses to alpha tropomyosin and its derivative peptides. The proliferative responses of PBMCs to these antigens were studied using (3)H thymidine incorporation assay. Serum samples were also screened by ELISA for autoantibodies against tropomyosin. Six of the 18 (33%) BD patients with posterior uveitis showed increased proliferative response to alpha tropomyosin or its derivative peptides, while none of the healthy, disease controls were positive. The mean lymphoproliferative responses to tropomyosin were significantly higher (P < 0.02) in the BD patients compared to healthy or disease controls. Higher titres of anti-tropomyosin antibodies were also seen in four of the 18 BD patients but none in the healthy or disease control groups (P < 0.002). The occurrence of these abnormalities supports a possible role for alpha tropomyosin as a self-antigen in a subset of patients with Behcet's disease.
Abstract: T regulatory cells play an important role in regulating T cell responses. Anti-ergotypic T cells are a subset of regulatory T cells that proliferate in response to activation markers, ergotopes, expressed on activated, and not on resting syngeneic T cells. Here we report the presence of anti-ergotypic T cells in lymph nodes, spleens and thymuses of naive rats. The development of anti-ergotypic T cells appeared to be independent of antigen priming, as thymocytes from one-day old rats exhibited significant anti-ergotypic proliferative responses. The anti-ergotypic T cells were found to be of the CD8+ phenotype, and included both TCRalpha/beta+ and TCRgamma/delta+ T cells. The TCRgamma/delta+ anti-ergotypic T cells secreted IFNgamma and TNFalpha in response to activated T cells; the TCRalpha/beta+ T cells proliferated but did not secret detectable cytokines. We found that the interaction between the anti-ergotypic T cells and stimulator T cells required cell-to-cell contact between the T cells. Professional APCs were not needed. The response of the TCRalpha/beta+CD8+ anti-ergotypic T cells was MHC-I restricted and B7-CD28 dependent; the response of the TCRgamma/delta+ anti-ergotypic T cells was B7-CD28 dependent, but was not inhibited by antibodies to classical MHC-I or MHC-II molecules. The existence of anti-ergotypic T cells in naive animals suggests that these cells might have a role in the regulation and maintenance of the immune system.
Abstract: We recently reported that soluble 60-kDa heat shock protein (HSP60) can directly activate T cells via TLR2 signaling to enhance their Th2 response. In this study we investigated whether HSP60 might also activate B cells by an innate signaling pathway. We found that human HSP60 (but not the Escherichia coli GroEL or the Mycobacterial HSP65 molecules) induced naive mouse B cells to proliferate and to secrete IL-10 and IL-6. In addition, the HSP60-treated B cells up-regulated their expression of MHC class II and accessory molecules CD69, CD40, and B7-2. We tested the functional ability of HSP60-treated B cells to activate an allogeneic T cell response and found enhanced secretion of both IL-10 and IFN-gamma by the responding T cells. The effects of HSP60 were found to be largely dependent on TLR4 and MyD88 signaling; B cells from TLR4-mutant mice or from MyD88 knockout mice showed decreased responses to HSP60. Care was taken to rule out contamination of the HSP60 with LPS as a causative factor. These findings add B cells to the complex web of interactions by which HSP60 can regulate immune responses.
Abstract: Alzheimer's disease (AD) is the most common human neurodegenerative disease, leading to progressive cognitive decline and eventually death. The prevailing paradigm on the pathogenesis of AD is that abnormally folded proteins accumulate in specific brain areas and lead to neuronal loss via apoptosis. In recent years it has become evident that an inflammatory and possibly autoimmune component exists in AD. Moreover, recent data demonstrate that immunization with amyloid-beta peptide is therapeutically effective in AD. The nature of CNS Ags that are the target of immune attack in AD is unknown. To identify potential autoantigens in AD, we tested sera IgG Abs of AD patients in immunoblots against brain and other tissue lysates. We identified a 42-kDa band in brain lysates that was detected with >50% of 45 AD sera. The band was identified by mass spectrometry to be aldolase A. Western blotting with aldolase using patient sera demonstrated a band of identical size. The Ab reactivity was verified with ELISAs using aldolase. One of 25 elderly control patients and 3 of 30 multiple sclerosis patients showed similar reactivity (p < 0.002). In enzymatic assays, anti-aldolase positive sera were found to inhibit the enzyme's activity, and the presence of the substrate (fructose 1,6-diphosphate) enhanced Ab binding. Immunization of rats and mice with aldolase in complete Freund's adjuvant was not pathogenic. These findings reveal an autoimmune component in AD, point at aldolase as a common autoantigen in this disease, and suggest a new target for potential immune modulation.
Abstract: Vascular endothelial growth factor (VEGF) and its receptors are critical in angiogenesis. The main player in the secretion and response to VEGF is the endothelial cell. We initiated this study to test whether T cells can secrete VEGF and are able to respond to it. Here we show that VEGF is secreted by T cells on stimulation by specific Ag or by IL-2 and by hypoxia; thus, activated T cells might enhance angiogenesis. Hypoxia also induced the expression in T cells of VEGFR2, suggesting that T cells might also respond to VEGF. Indeed, VEGF augmented IFN-gamma and inhibited IL-10 secretion by T cells responding to mitogen or Ag; thus, VEGF can enhance a Th1 phenotype. Encephalitogenic T cells stimulated in the presence of VEGF caused more severe and prolonged encephalomyelitis. Thus, T cells can play a role in angiogenesis by delivering VEGF to inflammatory sites, and VEGF can augment proinflammatory T cell differentiation.
Abstract: Ab's to the alpha-chain of the IL-2 receptor (anti-CD25) are used clinically to achieve immunosuppression. Here we investigated the effects of DNA vaccination with the whole CD25 gene on the induction of rat adjuvant arthritis. The DNA vaccine protected the rats and led to a shift in the cytokine profile of T cells responding to disease target antigens from Th1 to Th2. The mechanism of protection was found to involve the induction of an antiergotypic response, rather than the induction of anti-CD25 Ab's. Antiergotypic T cells respond to activation molecules, ergotopes, expressed on syngeneic activated, but not resting, T cells. CD25-derived peptides function as ergotopes that can be recognized by the antiergotypic T cells. Antiergotypic T cells taken from control sick rats did not proliferate against activated T cells and secreted mainly IFN-gamma. In contrast, antiergotypic cells from CD25-DNA-protected rats proliferated against activated T cells and secreted mainly IL-10. Protective antiergotypic T cells were found in both the CD4+ and CD8+ populations and expressed alpha/beta or gamma/delta T cell receptors. Antiergotypic alpha/beta T cells were MHC restricted, while gamma/delta T cells were MHC independent. Thus, CD25 DNA vaccination may induce protection from autoimmunity by inducing a cytokine shift in both the antiergotypic response and the response to the antigens targeted in the disease.
Abstract: OBJECTIVE: Adjuvant arthritis can be induced in Lewis rats by immunization with Mycobacterium tuberculosis (Mt). The mycobacterial 65-kd heat-shock protein (Hsp65) is targeted by arthritogenic T cells. However, Hsp65 and the mycobacterial 71-kd heat-shock protein are also recognized by T cells that can down-regulate adjuvant-induced arthritis (AIA). We have recently demonstrated that vaccination with human Hsp60 DNA inhibits AIA. The present study was undertaken to analyze the role of the T cell responses to self HSP molecules other than Hsp60 in the control of AIA. METHODS: Lewis rats were immunized with DNA vaccines coding for human Hsp70 or Hsp90 (Hsp70 plasmid [pHsp70] or pHsp90), and AIA was induced. The T cell response to Mt, Hsp60, Hsp70, and Hsp90 (proliferation and cytokine release) was studied, and the T cell response to Hsp60 was mapped with overlapping peptides. RESULTS: The Hsp70 or Hsp90 DNA vaccines shifted the arthritogenic T cell response from a Th1 to a Th2/3 phenotype and inhibited AIA. We detected immune crosstalk between Hsp70/90 and Hsp60: both the Hsp70 and Hsp90 DNA vaccines induced Hsp60-specific T cell responses. Similarly, DNA vaccination with Hsp60 induced Hsp70-specific T cell immunity. Epitope mapping studies revealed that Hsp60-specific T cells induced by pHsp70 vaccination reacted with known regulatory Hsp60 epitopes. CONCLUSION: T cell immunity to Hsp70 and to Hsp90, like Hsp60-specific immunity, can modulate the arthritogenic response in AIA. In addition, our results suggest that the regulatory mechanisms induced by Hsp60, Hsp70, and Hsp90 are reinforced by an immune network that connects their reactivities.
Abstract: Probiotic bacteria have beneficial effects in infectious and inflammatory diseases, principally in bowel disorders. In the case of chronic progressive autoimmune arthritides, a major goal of treatment is to reduce inflammation. We hypothesized that probiotic bacteria would ameliorate inflammation found in arthritis models. To assess this effect, Lewis rats were injected with 50 microg bovine alpha-tropomyosin (TRM) or complete Freund's adjuvant (CFA) to induce tropomyosin arthritis (TA) or adjuvant arthritis (AA), respectively. In both models, the rats were divided into 6 groups and fed 0.5 mL/d of the following suspensions: 1) heat-killed Lactobacillus GG (LGG) bacteria; 2) live LGG, both 10(11) colony-forming units (cfu)/L; 3) sterilized milk; 4) plain yogurt; 5) yogurt containing 10(11) cfu/L LGG; or 6) sterilized water. In the disease-prevention experiments, feeding started 1 wk before or after disease induction. In the therapeutic experiments, feeding was initiated at the onset of clinical arthritis. In all experiments, there were significant interactions between time and treatment (P < 0.001), except for milk, which had no effect in the therapeutic experiment. Histologically, rats fed yogurt containing LGG had a milder inflammation in all experiments (P < 0.05), whereas rats fed plain yogurt exhibited a moderate inflammatory score only in the prevention experiments. Anti-TRM antibody titers were not affected by any of the treatments in any of the experiments. Ingestion of live or heat-killed human LGG had a clinically beneficial effect on experimental arthritis. Our observation of the remarkable preventive and curative effect on arthritis using commercial yogurts containing lactobacilli, especially LGG, suggests the need for investigation of these agents in arthritic patients.
Abstract: We recently reported that immunization of mice with certain self-prion protein peptides induced specific T-cell and B-cell immune responses; importantly, this immunization was associated with a decrease in the number of protease-resistant PrP(Sc) particles recoverable in a transplanted, scrapie-infected syngeneic tumor. The present study was carried out to determine whether immunization with the immunogenic PrP peptides might influence the natural history of experimental scrapie in mice. We immunized C57BL/6 mice with self-prion peptides in complete Freund's adjuvant (CFA) or with CFA alone as a control and then infected the mice with mouse-adapted scrapie by injection either intraperitoneally or intracerebrally. We report here that immunization with CFA, irrespective of whether prion peptides were present in the inoculum, resulted in marked prolongation of survival of the mice, whether the challenge was intracerebral or intraperitoneal. Mice in the immunized and control groups that died contained equivalent amounts of PrP(Sc). Thus, CFA immunization has a therapeutic effect in experimental scrapie in mice, possibly by reducing the rate of PrP(Sc) accumulation in the brain.
Abstract: Beta-synuclein is a neuronal protein that accumulates in the plaques that characterize neurodegenerative diseases such as Parkinson's and Alzheimer's diseases. It has been proposed that immunization to peptides of plaque-forming proteins might be used therapeutically to help dissociate pathogenic plaques in the brain. We now report that immunization of Lewis rats with a peptide from beta-synuclein resulted in acute paralytic encephalomyelitis and uveitis. T cell lines and clones reactive to the peptide adoptively transferred the disease to naive rats. Immunoblotting revealed the presence of beta-synuclein in heavy myelin, indicating that the expression of beta-synuclein is not confined to neurons. These results add beta-synuclein to the roster of encephalitogenic self Ags, point out the potential danger of therapeutic autoimmunization to beta-synuclein, and alert us to the unsuspected possibility that autoimmunity to beta-synuclein might play an inflammatory role in the pathogenesis of neurodegeneration.
Abstract: Adjuvant arthritis (AA) is induced by immunizing Lewis rats with Mycobacterium tuberculosis suspended in adjuvant. The mycobacterial 65-kDa heat shock protein (HSP65) contains at least one epitope associated with the pathogenesis of AA: T cell clones that recognize an epitope formed by aa 180-188 of HSP65 react with self-cartilage and can adoptively transfer AA. Nevertheless, vaccination with HSP65 or some of its T cell epitopes can prevent AA by a mechanism that seems to involve cross-reactivity with the self-60-kDa HSP60. We recently demonstrated that DNA vaccination with the human hsp60 gene can inhibit AA. In the present work, we searched for regulatory epitopes using DNA vaccination with HSP60 gene fragments. We now report that specific HSP60 DNA fragments can serve as effective vaccines. Using overlapping HSP60 peptides, we identified a regulatory peptide (Hu3) that was specifically recognized by the T cells of DNA-vaccinated rats. Vaccination with Hu3, or transfer of splenocytes from Hu3-vaccinated rats, inhibited the development of AA. Vaccination with the mycobacterial homologue of Hu3 had no effect. Effective DNA or peptide vaccination was associated with enhanced T cell proliferation to a variety of disease-associated Ags, along with a Th2/3-like shift (down-regulation of IFN-gamma secretion and enhanced secretion of IL-10 and/or tumor growth factor beta1) in response to peptide Mt176-190 (the 180-188 epitope of HSP65). The regulatory response to HSP60 or its Hu3 epitope included both Th1 (IFN-gamma) and Th2/3 (IL-10/tumor growth factor beta1) secretors. These results show that regulatory mechanisms can be activated by immunization with relevant self-HSP60 epitopes.
Abstract: Behçet's syndrome is a multi-system inflammatory disease affecting mainly the oral and urogenital mucosa and the uveal tract. The etiology and pathogenesis of Behçet's syndrome are unknown, but autoimmune mechanisms are implicated. We initiated this work to identify self-antigens targeted by patients with Behçet's syndrome. We used patient sera to immuno-blot tissue lysates, and we found that some patients manifest antibodies to a 37-kDa band. The 37-kDa band was detected in extracts of skin, tongue, vagina, muscle and heart but not in brain, kidney, lung, liver, intestine and thymus. In-gel digestion and mass spectrometry revealed the band to be alpha-tropomyosin. Autoimmunity to alpha-tropomyosin can be pathogenic; immunized Lewis rats developed lesions in the uveal tract and skin, with features of Behçet's disease.
Abstract: This study was designed to test the process of selecting encephalitogenic T cell lines in the Lewis rat using recombinant human IL-2 (rhIL-2) in comparison to TCGF. The lines were tested for growth, antigen induced proliferation, cytokine production, V-beta 8.2 expression and pathogenicity. We now report that rhIL-2 and TCGF were equally effective in supporting short-term pathogenic T-cell lines with similar proportion of V-beta 8.2 usage. For the maintenance of long term lines, however, TCGF was superior to IL-2. The concentration of rhIL-2 influenced the cultures: 10 units/ml led to more T-cell proliferation than either 2 or 50 units/ml. However, 50 units/ml of IL-2 led to enhanced Th1 polarization. Thus, the type and concentration of growth factors can influence both the propagation of T cells and their phenotype.
Abstract: Adjuvant arthritis (AA) is an autoimmune disease inducible in rats involving T cell reactivity to the mycobacterial 65-kDa heat shock protein (HSP65). HSP65-specific T cells cross-reactive with the mammalian 60-kDa heat shock protein (HSP60) are thought to participate in the modulation of AA. In this work we studied the effects on AA of DNA vaccination using constructs coding for HSP65 (pHSP65) or human HSP60 (pHSP60). We found that both constructs could inhibit AA, but that pHSP60 was more effective than pHSP65. The immune effects associated with specific DNA-induced suppression of AA were complex and included enhanced T cell proliferation to a variety of disease-associated Ags. Effective vaccination with HSP60 or HSP65 DNA led paradoxically to up-regulation of IFN-gamma secretion to HSP60 and, concomitantly, to down-regulation of IFN-gamma secretion to the P180-188 epitope of HSP65. There were also variable changes in the profiles of IL-10 secretion to different Ags. However, vaccination with pHSP60 or pHSP65 enhanced the production of TGFbeta1 to both HSP60 and HSP65 epitopes. Our results support a regulatory role for HSP60 autoreactivity in AA and demonstrate that this control mechanism can be activated by DNA vaccination with both HSP60 or HSP65.
Abstract: Prion diseases are caused by conformational alterations in the prion protein (PrP). The immune system has been assumed to be non-responsive to the self-prion protein, therefore, PrP autoimmunity has not been investigated. Here, we immunized various strains of mice with PrP peptides, some selected to fit the MHC class II-peptide binding motif. We found that specific PrP peptides elicited strong immune responses in NOD, C57BL/6 and A/J mice. To test the functional effect of this immunization, we examined the expression of proteinase-K-resistant PrP by a scrapie-infected tumor transplanted to immunized syngeneic A/J mice. PrP peptide vaccination did not affect the growth of the infected tumor transplant, but significantly reduced the level of protease-resistant PrP. Our results demonstrate that self-PrP peptides are immunogenic in mice and suggest that this immune response might affect PrP-scrapie levels in certain conditions.
Abstract: Prion diseases are caused by abnormal folding of the prion protein. The paradigm is that the prion protein is not immunogenic because the immune system must be tolerant to such a self protein. In an attempt to identify immunogenic prion peptides, we immunized Lewis rats with peptides that fitted the MHC class II RT1.B(1)motif. Both humoral and cellular immunity to the prion peptides were obtained without any harmful effects to young animals. However, when 8-month-old rats were immunized, a sixth (6/36) of the rats developed severe skin inflammation with concomitant hair loss. These findings suggest that immunity to self-prion peptides can be readily induced in Lewis rats and that this immune response may have pathogenic consequences in older rats.
Abstract: Autoimmune T cells against central nervous system myelin associated peptide reduce the spread of damage and promote recovery in injured rat spinal cord, findings that might lead to neuroprotective cell therapy without risk of autoimmune disease.
Abstract: Experimental autoimmune encephalomyelitis (EAE) was induced in Lewis rats either by active immunization with myelin basic protein (MBP) or by adoptive transfer using anti-MBP specific CD4(+)T cells. Treatment with human polyclonal immunoglobulins (IgG) effectively suppressed active EAE. Time-dependent experiments demonstrated that the effect of IgG was manifested only when treatment was given immediately after immunization; administration from day 7 after disease induction did not suppress the disease. In the adoptive transfer model of EAE, IgG had no effect in vivo. However, pretreatment in vitro of the antigen-specific T-cells with IgG inhibited their ability to mediate adoptive EAE, as it did in active EAE. Similarly, in vitro IgG pretreatment of the antigen-specific T-cells suppressed the proliferative response to MBP. Fluorescent Activated Cell Sorter (FACS) analysis demonstrated the binding of IgG to activated T-cell lines that was inhibited by soluble Fc molecules. The differential effects of IgG on active EAE and on the adoptive transfer of EAE suggest that IgG in vivo can suppress disease by acting during the early phase of the immune response which involves naive T cells. The inhibition of T-cell proliferation and adoptive transfer of EAE by incubation of T cells in vitro appears to require higher concentrations of IgG than those obtained in vivo.
Abstract: In the Lewis rat, the dominant T cell repertoire to myelin basic protein (MBP) is directed to the peptide 71-87 and the T cell receptors of pathogenic T cells are of the Vbeta 8.2 genotype with short CDR3 sequences having a characteristic motif. However, this paradigm has been reached through analysis of long-term encephalitogenic lines and clones. We initiated the present study to examine the process of selection of the TCR Vbeta 8.2 and characteristic CDR3 motifs upon immunization with guinea-pig MBP, and rat or guinea-pig 71-87 peptides. We found that the dominance of Vbeta 8.2 developed progressively over 4-6 in vitro stimulations. Following immunization with rat 70-86, which differs from the guinea-pig peptide in one amino acid at position 78, the dominance of Vbeta 8.2 and the characteristic CDR sequences are not seen. Thus, Vbeta 8.2 dominance and specific CDR3 TCR motifs are seen with heterologous GpMBP but not with self rat MBP.
Abstract: We recently demonstrated that autoimmune T cells protect neurons from secondary degeneration after central nervous system (CNS) axotomy in rats. Here we show, using both morphological and electrophysiological analyses, that the neuroprotection is long-lasting and is manifested functionally. After partial crush injury of the rat optic nerve, systemic injection of autoimmune T cells specific to myelin basic protein significantly diminished the loss of retinal ganglion cells and conducting axons, and significantly retarded the loss of the visual response evoked by light stimulation. These results support our challenge to the traditional concept of autoimmunity as always harmful, and suggest that in certain situations T cell autoimmunity may actually be beneficial. It might be possible to employ T cell intervention to slow down functional loss in the injured CNS.
Abstract: Partial injury to the spinal cord can propagate itself, sometimes leading to paralysis attributable to degeneration of initially undamaged neurons. We demonstrated recently that autoimmune T cells directed against the CNS antigen myelin basic protein (MBP) reduce degeneration after optic nerve crush injury in rats. Here we show that not only transfer of T cells but also active immunization with MBP promotes recovery from spinal cord injury. Anesthetized adult Lewis rats subjected to spinal cord contusion at T7 or T9, using the New York University impactor, were injected systemically with anti-MBP T cells at the time of contusion or 1 week later. Another group of rats was immunized, 1 week before contusion, with MBP emulsified in incomplete Freund's adjuvant (IFA). Functional recovery was assessed in a randomized, double-blinded manner, using the open-field behavioral test of Basso, Beattie, and Bresnahan. The functional outcome of contusion at T7 differed from that at T9 (2.9+/-0.4, n = 25, compared with 8.3+/-0.4, n = 12; p<0.003). In both cases, a single T cell treatment resulted in significantly better recovery than that observed in control rats treated with T cells directed against the nonself antigen ovalbumin. Delayed treatment with T cells (1 week after contusion) resulted in significantly better recovery (7.0+/-1; n = 6) than that observed in control rats treated with PBS (2.0+/-0.8; n = 6; p<0.01; nonparametric ANOVA). Rats immunized with MBP obtained a recovery score of 6.1+/-0.8 (n = 6) compared with a score of 3.0+/-0.8 (n = 5; p<0.05) in control rats injected with PBS in IFA. Morphometric analysis, immunohistochemical staining, and diffusion anisotropy magnetic resonance imaging showed that the behavioral outcome was correlated with tissue preservation. The results suggest that T cell-mediated immune activity, achieved by either adoptive transfer or active immunization, enhances recovery from spinal cord injury by conferring effective neuroprotection. The autoimmune T cells, once reactivated at the lesion site through recognition of their specific antigen, are a potential source of various protective factors whose production is locally regulated.
Abstract: We recently reported that the posttraumatic spread of degeneration in the damaged optic nerve can be attenuated by the adoptive transfer of autoimmune T cells specific to myelin basic protein. However, it would be desirable to obtain immune neuroprotection free of any possible autoimmune disease. In an attempt to obtain disease-free immune neuroprotection, we used the synthetic four-amino acid polymer copolymer 1 (Cop-1), which is known not to be encephalitogenic despite its cross-reactivity with myelin basic protein. We show here that active immunization with Cop-1 administered in adjuvant, as well as adoptive transfer of T cells reactive to Cop-1, can inhibit the progression of secondary degeneration after crush injury of the rat optic nerve. These results have implications for the treatment of optic neuropathies.
Abstract: Regulatory sequences used in plasmids for naked DNA vaccination can modulate cytokine production in vivo. We demonstrate here that injection of plasmid DNA can suppress the prototypic T cell-mediated autoimmune disease, experimental autoimmune encephalomyelitis, by inducing IFN-gamma.
Abstract: Autoimmunity to antigens of the central nervous system is usually considered detrimental. T cells specific to a central nervous system self antigen, such as myelin basic protein, can indeed induce experimental autoimmune encephalomyelitis, but such T cells may nevertheless appear in the blood of healthy individuals. We show here that autoimmune T cells specific to myelin basic protein can protect injured central nervous system neurons from secondary degeneration. After a partial crush injury of the optic nerve, rats injected with activated anti-myelin basic protein T cells retained approximately 300% more retinal ganglion cells with functionally intact axons than did rats injected with activated T cells specific for other antigens. Electrophysiological analysis confirmed this finding and suggested that the neuroprotection could result from a transient reduction in energy requirements owing to a transient reduction in nerve activity. These findings indicate that T-cell autoimmunity in the central nervous system, under certain circumstances, can exert a beneficial effect by protecting injured neurons from the spread of damage.
Abstract: Myelin basic protein (MBP) is a major protein of central nervous system myelin which can induce experimental autoimmune encephalomyelitis (EAE) in susceptible laboratory animals. The role of T cells in the induction of EAE has been extensively studied, but the antibody response to MBP has not been well characterized. In the present work, we immunized rats with encephalitogenic guinea-pig MBP and mapped autoreactive antibodies binding to peptides in the rat MBP sequence. We studied the responses of the Lewis rat strain, susceptible to EAE, and the responses of the Fischer and Brown-Norway (BN) rats, resistant to EAE. We found that Lewis rats immunized to guinea-pig MBP develop antibodies to a diversity of MBP epitopes with a dominance of MBP peptide p11-30 and peptides in the 71-140 region. Fischer rats showed a similar pattern of antibody specificities, but with higher titers than the Lewis rats. BN rats, in contrast, developed a very low titer of antibodies and lacked a response to p11-30. Thus, there is no clear correlation between the nature of the anti-MBP antibody response and the state of susceptibility or resistance to EAE induction in the different rat strains.
Abstract: Allograft rejection is a process of immune reactivity triggered by foreign transplantation antigens. We now demonstrate that the 60-kDa heat shock protein (hsp60), a molecule that is identical in the donor and the recipient, can regulate allograft immunity. In wild-type mice, hsp60 expression was greatly enhanced in allografts being rejected. By using MHC class II (Ealpha) promoter hsp60 transgenic mice either as donors of skin with enhanced expression of hsp60, or as allograft recipients with decreased hsp60 autoimmunity, we found that augmented expression of mouse hsp60 in the allograft accelerated its rejection, whereas reduced autoimmunity to mouse hsp60 in graft recipients delayed the process. Moreover, in nontransgenic mice, therapeutic administration of hsp60 or hsp60 peptides, known to modulate naturally occurring hsp60 autoimmunity, led to delayed allograft rejection. Thus, we demonstrate that hsp60 expression and hsp60 autoimmunity can influence and modify the immune response to foreign antigens. Hence, autoimmunity to self-hsp60 epitopes is not necessarily an aberration, but may serve physiologically and therapeutically to modulate foreign immunity.
Abstract: PURPOSE: Idiopathic inflammation of the cornea, keratitis, has been proposed to result from an autoimmune process, but thus far no convenient animal model of keratitis exists. An attempt was made to establish an animal model for keratitis, to investigate possible autoimmune mechanisms. METHODS: T-cell lines were established from lymph node cells removed from rats immunized with bovine corneal epithelium (BCE) extract. After restimulation in vitro with BCE or a specific corneal antigen, the cells were transferred by intraperitoneal injection into naive rats, rats subjected to total body irradiation, or rats in which only one eye was irradiated. RESULTS: Neither direct immunization with corneal antigens nor transfer of activated anti-corneal T-cells into naive rats gave any signs of keratitis. Irradiation alone did not induce corneal inflammation. Transfer of corneal-specific activated T cells into irradiated rats produced keratitis starting around day 4 and culminating around day 8. The disease was self-limiting and the severity dependent on the dose and site of radiation. Keratitis was characterized by corneal haze, conjunctival and episcleral hyperemia, episcleral hemorrhages, chemosis, corneal infiltrates, and vascularization. Immunohistochemistry showed T-cell and macrophage infiltration of epithelium and stroma in the affected corneas. CONCLUSIONS: Thus, keratitis may be produced by T cells reactive to corneal antigens, provided that the target tissue has been made susceptible by irradiation. The effectiveness of T-cell vaccination in preventing adoptive keratitis suggests that systemic as well as local tissue factors may regulate the disease process.
Abstract: The central nervous system (CNS) enjoys a unique relationship with the immune system. Under non-pathological conditions, T cells move through the CNS but do not accumulate there. CNS trauma has been shown to trigger a response to CNS self-antigens such as myelin basic protein (MBP). Here, we examined whether the injured CNS tissue undergoes changes that permit T cell accumulation. We found that injury to CNS white matter, such as the optic nerve, led to a transiently increased accumulation of T cells (between days 3 and 21). In Lewis rats with unilaterally injured optic nerves, systemic administration of passively transferred T cells recognizing either self-antigen (MBP) or non-self-antigen (ovalbumin) resulted in accumulation of the T cells in injured optic nerve, irrespective of their antigenic specificity. The effect of the T cells on the damaged nerve, the lack of selectivity in T cell accumulation and the mechanism underlying non-selective accumulation are discussed.
Abstract: The process of thymic selection is critical for the generation of the mature T-cell repertoire, yet the nature of the self-peptides that serve this function is not known. Several studies suggest that tissue-specific auto-antigens are expressed in the thymus. We initiated this study to examine the expression of a panel of auto-antigens related to several autoimmune diseases in the thymus, peripheral lymphoid organs, and various cell lines. We looked for the expression of these antigens by reverse transcriptase-polymerase chain reaction, fluorescence-activated cell sorter (FACS) analysis, immunoblotting, and immunoprecipitation. We found that in the thymus there is evidence for the expression of a wide variety of disease-related self-antigens including myelin antigens, insulin, cardiac myosin, and retinal S antigen. By FACS analysis, several monoclonal anti-myelin basic protein antibodies were found to bind to immune cells. In Western blotting, we could find in the thymus and other lymphoid organs the expression of myelin basic protein, proteolipid protein, and cyclic nucleotide phosphodiesterase; in contrast, the staining for myelin oligodendrocyte glycoprotein, microtubule-associated Tau protein, and insulin were negative in these organs. The results of these studies confirm that there is evidence for the expression of a variety of auto-antigens in the immune system, both at the mRNA and protein levels, potentially enabling them to participate in the process of thymic education.
Abstract: The MHC class II molecule of the non-obese diabetic (NOD) mice, I-Ag7, is associated with susceptibility to autoimmune diabetes. To try to understand the molecular basis of this association, we analyzed the peptide binding properties and intracellular behavior of I-Ag7 in comparison with other I-A haplotypes. We found that I-Ag7 molecules manifested normal intracellular trafficking and lifespan, and a small but clearly detectable fraction of I-Ag7 in the cells formed SDS-resistant compact dimers. The binding of an antigenic reference peptide to I-Ag7 was stable and was accompanied by compact dimer formation. Our analysis of the binding specificity of I-Ag7 revealed a peptide binding motif of nine amino acids with a degenerate position at P1 and three conserved anchor positions: P4, P6 and P9. An allele-specific preference for negatively charged residues was found at P9, apparently due to the presence of the rare Ser residue at position 57 of the I-Ag7 beta chain. These findings could have implications for the mechanisms of MHC-mediated susceptibility to autoimmune diabetes in the NOD mice.
Abstract: Corticotropin-releasing factor (CRF) exerts a major role in the stress response. Both CRF and urocortin, a newly discovered neuropeptide homologous to CRF, suppressed experimental autoimmune encephalomyelitis (EAE). Suppression of paralysis with CRF involved stimulation of the hypothalamic-pituitary-adrenal axis and inhibitory effects on an encephalitogenic T cell line. While CRF increased glucocorticoid production, which is known to block EAE, it also suppressed EAE in adrenalectomized rats, where glucocorticoid stimulation via CRF plays no role. Moreover, the encephalitogenicity of a T cell line exposed to CRF in vitro was reduced. Stress may influence autoimmune disease through the hypothalamic-pituitary-adrenal axis and directly via the immune system.
Abstract: A variable region gene of the T-cell receptor, V beta 8.2, is rearranged, and its product is expressed on pathogenic T cells that induce experimental autoimmune encephalomyelitis (EAE) in H-2u mice after immunization with myelin basic protein (MBP). Vaccination of these mice with naked DNA encoding V beta 8.2 protected mice from EAE. Analysis of T cells reacting to the pathogenic portion of the MBP molecule indicated that in the vaccinated mice there was a reduction in the Th1 cytokines interleukin-2 (IL-2) and interferon-gama. In parallel, there was an elevation in the production of IL-4, a Th2 cytokine associated with suppression of disease. A novel feature of DNA immunization for autoimmune disease, reversal of the autoimmune response from Th1 to Th2, may make this approach attractive for treatment of Th1-mediated diseases like multiple sclerosis, juvenile diabetes and rheumatoid arthritis.
Abstract: Most studies of apoptosis on T lymphocytes have examined the effects of various stimuli on immature T cells from the thymus. Previous work has indicated that apoptosis of mature memory T cells may be an important pathophysiologic mechanism in diseases such as AIDS, cancer, and autoimmunity. The effect of IL-2 on apoptosis of T cells is not clear. Therefore, we studied the ability of IL-2 to rescue Ag-specific T cells from apoptosis. We found that IL-2, in a dose-dependent manner, prevented T cells from entering apoptosis induced by gamma-irradiation, mitomycin C, or dexamethasone. This effect was specific for IL-2; IL-1 beta, IL-6, or IFN-gamma could not reproduce it. In contrast to Ag-specific T cells, immature T cells and naive mature peripheral T cells could not be rescued by IL-2 from radiation-induced apoptosis. Apoptosis rescue by IL-2 was associated with the induction of bcl-2 mRNA and protein. This induction could not be attributed to the effects of IL-2 on the cell cycle, as T cells that were prevented from cell cycle progression by irradiation showed a similar induction of bcl-2. Rescued cells retained their Ag-specific proliferative capacity and in vivo functions. These findings demonstrate that the apoptotic death of Ag-specific T cell lines, cells which can be regarded as a model for memory T cells, can be prevented with IL-2. This effect may have important therapeutic implications for patients receiving chemotherapy or radiotherapy, and for patients with AIDS who develop immunodeficiency primarily as a result of loss of Ag-specific memory T cells.
Abstract: T cells are considered to be of prime importance in immune regulation of both B and T cell functions. The targets of recognition in T-T cell interactions are not clear. Most recent experimental work has focused on the idiotypic regulatory interactions mediated by TCR peptides. There is experimental evidence that regulatory cells exist that do not recognize the TCR. This type of regulation is selectively induced by activated T cells. Therefore, we designed this study to examine the possible role of cytokine receptors as targets of immune regulation. We tested two peptides of IL-2R alpha-chain, 2 of IL-2R beta-chain, and one of TNFR (p60). All peptides were found to be immunogenic at inducing T cell proliferation and four induced Abs in Lewis rats. We generated T cell lines to these five peptides, and tested them both in vitro and in vivo. We found that the T cells exhibited a proliferative response when cultured with activated, irradiated stimulator cells that were augmented upon addition of the cytokine receptor peptide. The cytokine profile of the lines was characterized as well as the Vbeta gene composition. One of the lines significantly protected against active encephalomyelitis. These results point at cytokine receptors as possible targets of immune regulation and T-T cell interactions.
Abstract: The specificity of peptide binding to MHC molecules is defined by binding motifs composed of several relatively conserved anchor positions. The peptide binding motifs of murine MHC class II I-A molecules are functionally important but poorly characterized. Here we use peptide binding studies and isolation of naturally presented peptides to characterize the peptide binding motif of the MHC class II I-A molecule, RT1.BI, a molecule that is involved in experimental autoimmunity in the Lewis rat. We now report that, similar to other class II motifs, the RT1.BI motif consists of a nonamer sequence with four major anchor positions (P1, P4, P6 and P9). Residues at P4 and P9, rather than at P1, appeared to be particularly important for binding. Negatively charged residues were favored at P9, consistent with the presence of a serine at position 57 of the RT1.BI beta chain. This RT1.BI motif could be observed in the dominant autoantigenic T cell epitopes mapped previously in the Lewis rat. These results highlight a general similarity and some important differences in the organization of MHC class II peptide binding motifs. The reported RT1.BI motif should facilitate the prediction and design of T cell epitopes for the induction and control of experimental autoimmune diseases in Lewis rat models.
Abstract: Co-stimulatory signals provided by surface receptors of antigen-presenting cells (APC) are crucial for the activation of CD4+ T cells, classically measured by cell proliferation or IL-2 secretion. The contribution of APC co-stimulatory signals to the acquisition of various effector functions by activated T cells is not fully understood. We have now examined the importance of surface-mediated co-stimulation by APC for activation of the effector potential of T cell clones mediating experimental allergic encephalomyelitis (EAE). We now report that T cell clones can be activated to produce EAE not only with APC but also by antibody-mediated TCR cross-linking in the presence of a mixture of T cell growth factors. Without activation, the T cell clones did not cause EAE. Therefore, at least some types of T cells can be activated to express their effector potential in the absence of any surface co-stimulatory signals requiring intact APC.
Abstract: The cellular immunology of experimental autoimmune encephalomyelitis, a model for multiple sclerosis, has been studied, for the most part, using T cells directed to dominant epitopes of the Ag myelin basic protein (MBP). To characterize T cells reactive to cryptic epitopes of MBP, we immunized Lewis rats with each of 17 overlapping peptides of the 18.5-kDa isoform of rat MBP. We found that, in addition to the known 71-90 epitope, six other peptides induced active encephalomyelitis in the majority the injected rats. T cell lines raised to six different MBP epitopes were encephalitogenic upon adoptive transfer to naive rats. In contrast to the T cells specific for the dominant 71-90 peptide, the T cell lines reactive to cryptic epitopes were not restricted in their TCR genes to V beta 8.2, and some of the lines caused prolonged disease. Thus, T cells of different specificities and TCR usage can be pathogenic.
Abstract: The current therapy for human autoimmune disease is based on nonselective immunosuppression achieved by corticosteroids or cytotoxic drugs. This form of therapy is toxic and frequently not effective in curing the disease. The study of experimental autoimmune disease models indicates that the pathogenic population of immune cells is restricted in terms of T-cell receptor gene usage and peptide epitopes recognized in the self-antigens. The recent developments in understanding of the pathophysiology of autoimmune disease point to the crucial role of the pathogenic T cell, the autoantigenic peptide, and the major histocompatibility complex molecules as well as the regulatory T-cell population in the disease process. The purpose of this review is to describe the use of vaccines to prevent and treat autoimmune disease. Encouraging results in animal models using vaccines based on the pathogenic T cell or the autoantigen have prompted the design of novel and selective immune-based therapies for human autoimmune disease.
Abstract: The extravasation of activated T lymphocytes through blood vessel walls and their migration to inflammatory loci are associated with secretion of extracellular matrix (ECM)-degrading enzymes, such as heparanase, which degrades heparan sulfate (HS) moieties of the ECM. The HS-degrading activity of heparanase was found to be inhibited by HS and heparin. Since induction of experimental autoimmune encephalomyelitis (EAE) requires extravasation and migration of autoimmune T cells, degradation of ECM by heparanase is expected to be involved in induction of the disease. Herein, we examined whether laminarin sulfate, a polysulfated polysaccharide (PSS) isolated from the cell walls of seaweeds and subjected to chemical sulfation, could inhibit ECM degradation by mammalian heparanase, and could prevent EAE. PSS was a more potent inhibitor of heparanase-mediated degradation of ECM than heparin. In-vivo, PSS, injected once a week, inhibited the severity of actively-induced EAE in rats. However, inhibition of EAE was not due to an overall suppression of autoimmune T cells, since PSS enhanced the proliferation of myelin basic protein (MBP)-specific, encephalitogenic T cells. PSS-activated autoimmune T cells, but not MBP-activated cells, failed to induce EAE in recipient rats. Moreover, rats injected with PSS-activated T cells were resistant to induction of EAE by anti-MBP CD4+ T cells. Thus, PSS may have potential clinical applications in the treatment of autoimmune diseases.
Abstract: Uveitis of unknown etiology is known to occur in association with various systemic disorders. We now report that anterior uveitis (AU) can be produced by T cell immunity to myelin basic protein (BP) and accompanies experimental autoimmune encephalomyelitis (EAE). EAE with AU was induced in Lewis rats by immunization to BP in CFA or by immunization to various BP peptides including the encephalitogenic 71-90 peptide. Slit-lamp biomicroscopy of BP-immunized Lewis rats revealed AU, characterised by inflammation of the iris, in 73% of the eyes. The onset of AU in actively immunized rats varied between days 12 and 26, often appearing after spontaneous remission of the paralysis, the hallmark of EAE. The course of AU was progressive, affecting more than 50% of the surface of the iris in 16 of 29 diseased eyes. Like the paralysis, the AU was self-limiting: within 2 weeks the disease remitted. In addition, AU could be adoptively transferred to naive and irradiated rats by a T cell clone specific for BP peptide 71-90. The present observations are compatible with the idea that AU may be triggered by BP-reactive T cells. The myelinated nerves present in the iris have been shown to contain BP. However, these peripheral nerves would now appear to be the only peripheral nerves susceptible to acute EAE.
Abstract: The expression of major histocompatibility complex (MHC) class II molecules in murine T cells has been controversial. We therefore reexamined the transcription, synthesis and surface expression of MHC class II determinants in rat T cells both in vivo and in vitro. In naive rats, a large proportion of small CD4+8+ and mature CD4+8-/CD4-8+ thymocytes was found to be MHC class II positive. At least some of the MHC class II molecules found on thymocytes were actively synthesized. The synthesis of MHC class II proteins was detected in peripheral T cells activated in vivo during induction of experimental allergic encephalomyelitis (EAE). A proportion of T cells from the inflammatory lesion of EAE exhibited MHC class II on the surface. A panel of helper T cell lines and clones was shown to synthesize MHC class II proteins. In a prototypic clone, a weak constitutive expression of MHC class II was observed. During activation, the rate of endogenous MHC class II synthesis increased and passive absorption of surface MHC class II from other cells occurred. Our data demonstrate the expression of MHC class II molecules in rat T cells in both the thymus and periphery. Since the primary function of MHC class II molecules is the presentation of peptide epitopes to T cells, these results call attention to the possible role of MHC class II molecules in T-T interactions during T cell maturation and activation.
Abstract: This paper describes some of the factors involved in the regulation of EAE and of autoimmunity in general. The immunological homunculus is discussed.
Abstract: In the last 10 years, our laboratory has investigated the role of T cells in the induction and therapy of experimental autoimmune diseases. In several animal model T cell lines and clones that were expanded in vitro by repeated culture with the autoantigen were found to be pathogenic. Inoculation of pathogenic T cells after attenuation resulted in protection of the animals against a future attempt to induce the disease: this form of therapy was termed T cell vaccination (TCV). Several forms of TCV were developed, including the administration of T cell lines attenuated by irradiation or mitomycin C, membrane modified cells and sub-pathogenic doses of unmodified T cells. The vaccinating effect was found to be mediated by T cells. Vaccinated animals had both CD4 T cells that responded to the vaccine and CD8 T cells that suppressed its response to the autoantigen. The major obstacle to the clinical application of TCV in human autoimmune diseases is the fact that the nature of autoantigens initiating and perpetuating the disease are not known.
Abstract: An epitope present in the 71-90 sequence of basic protein (BP) has been identified as the dominant epitope recognized by most Lewis rat encephalitogenic T cells isolated during experimental autoimmune encephalomyelitis (EAE). In the present study, we investigated the BP epitopes recognized by Lewis rat T cells in naive rats, in rats suffering from acute EAE, and in recovered rats. T cells isolated from the spinal cord lesions and from the lymph nodes were studied using T cell lines and bulk cultures. Virulence of the T cells was assayed by adoptive transfer. We now report that naive and recovered Lewis rats are populated with T cells reactive to a variety of BP epitopes and only a minority are specific for the 71-90 epitope. In contrast, the induction of EAE was associated with a predominance of T cells reactive to the 71-90 epitope. T cells recovered from naive, diseased, or recovered rats were found to be virulent upon passive transfer. Some of these virulent T cells were specific to BP epitopes other than the 71-90 epitope. There was no major difference in the BP specificities of T cells isolated from the lesions and from the lymph nodes. Thus, natural T cell reactivity to BP is heterogeneous and pathogenicity is not confined to one particular epitope, active disease is characterized by a dominant response to the 71-90 epitope, and recovery is marked by a return to heterogeneity.
Abstract: To characterize the cellular immune response in an autoimmune lesion, we investigated the accumulation of specific T cells in the central nervous system in actively induced experimental autoimmune encephalomyelitis (EAE) in Lewis rats, using a limiting dilution analysis (LDA) assay for T cells that proliferate in response to antigens. Lymphocytes isolated from the spinal cord infiltrate were compared with cells from the popliteal lymph nodes with respect to frequency of cells responding to basic protein (BP), mycobacterium tuberculosis (MT), the 65-kD heat shock protein (hsp65), allogeneic brown norway spleen cells, and concanavalin A. Additionally, we compared the BP frequency in acute EAE of cells from the spinal cord, peripheral blood, spleen and lymph nodes, and the spinal cord and lymph node after recovery from EAE. We found that acute EAE was associated with marked enrichment of BP-reactive T cells in the spinal cord relative to their frequency in the lymphoid organs and peripheral blood. The infiltrate was also enriched for T cells responding to hsp65; alloreactive T cells, in contrast, were not enriched. The frequency of BP reactive T cells in the spinal cord was highest at the peak of paralysis; however, BP-reactive T cells could still be detected at moderate frequencies after clinical recovery. We established BP- and Mycobacteria-reactive T cell lines from the spinal infiltrates that were CD4+ and TcR alpha beta +. Most of the BP lines were found to react to the major encephalitogenic epitope of guinea pig BP for rats (amino acids 71-90); these lines were found to mediate EAE in naive recipients. T cell lines recognizing other epitopes of BP were not encephalitogenic. All of the lines responsive to Mycobacteria recognized hsp65 or hsp70. These results indicating that the immune infiltrate in active EAE is enriched with cells responding to the autoantigen and to hsp65 were confirmed in EAE adoptively transferred by anti-BP T cell clone.
Abstract: We examined T cells isolated from an autoimmune tissue lesion and from lymphoid organs for their ability to secrete tumor necrosis factor-alpha (TNF-alpha) and to adhere to extracellular matrix (ECM) proteins. CD4+ T cells were obtained from spleens, popliteal lymph nodes, and spinal cords of Lewis rats that had been immunized with myelin basic protein (MBP) to induce experimental autoimmune encephalomyelitis (EAE). We now report that, irrespective of whether or not the T cells were activated with MBP or the T cell mitogen concanavalin A (ConA), the T cells isolated from the spinal cord lesions secreted greater amounts of TNF-alpha and adhered better to ECM than did T cells from the draining lymph node. Thus, the lesions of EAE concentrate a subpopulation of CD4+ T cells with enhanced ability to interact with blood vessel wall components and to secrete TNF-alpha.
Abstract: The incidence and significance of elevated serum levels of creatine phosphokinase (CPK) in febrile diseases were studied prospectively in all patients admitted with fever to a department of medicine during 1 year. High serum CPK levels were detected in 70 (28%) of 247 febrile patients but in only six (6%) of 105 afebrile control patients (P = .0001). Elevated CPK levels were not related to any specific diagnosis. Logistic regression analysis identified five factors that correlated both significantly and independently with elevation of CPK values: increased blood urea nitrogen level, low serum phosphate level, a stuporous or comatose state, tremor, and muscle tenderness. Myoglobinuria, detected in 14 patients, was predictive of a fatal outcome, but a high CPK level by itself was not an independent correlate of mortality. In summary, CPK elevation is not uncommon in febrile diseases, but because it does not reflect a specific etiology it does not necessarily indicate that an extensive diagnostic work-up is required.
Abstract: Among 244 patients aged 18 to 98 years who were consecutively hospitalized in a department of internal medicine because of a febrile disease, 52 (21%) were bacteremic. On a logistic regression analysis, five variables known within 24 hours of admission were found to be associated both significantly and independently with bacteremia: low serum albumin level, low premorbid performance status, chills, renal failure, and an assumptive diagnosis of urinary tract infection on admission. The logistic model was used to divide patients into three groups. In group 1, the percentage of bacteremic patients was 5%, in group 2, 40%, and in group 3, 83%. The percentage of deaths in the three groups was 0%, 23%, and 50%, respectively. The model was validated in a second group of 257 patients. The percentage of bacteremia was 1% in group 1, 23% in group 2, and 65% in group 3. The death rate in three groups was 3%, 4%, and 35%, respectively. The accuracy of the attending physician in diagnosing bacteremia within 24 hours of hospitalization was compared with that of the model. Use of the model could have improved the diagnostic accuracy in 5% of the patients in group 1 and in 18% of patients in group 3.
Abstract: Effective T cell vaccination against experimental autoimmune diseases involves treatment with activated, autoimmune T lymphocytes. The present study was undertaken to learn whether antigen-specific T cells present in low frequency could be selected in vitro without using the specific antigen. The rat models of adjuvant arthritis and experimental autoimmune encephalomyelitis were investigated using proliferation assays and limiting dilution techniques to quantify the changes in reactivity of a heterogenous population of lymphocytes to the relevant antigen. Stimulation with concanavalin A for 2 d and then culture in IL-2-containing medium led to a substantial increase in the activity and frequency of the specific autoimmune T cells. Enrichment of antigen-specific T cells could be demonstrated using lymph node, spleen, or peripheral blood lymphocytes, from rats late in the course of disease. The effect was not evident in lymphocytes from the thymus. These results are relevant to the clinical application of T cell vaccination and to investigation of self-antigens in autoimmune disease.
Abstract: We investigated the relationship between therapy with aminoglycoside antibiotics and alterations in serum liver enzymes and bilirubin. One hundred fourteen patients treated with aminoglycosides and 96 treated with other antibiotics were assessed prospectively during eight days. No elevation in serum alanine aminotransferase, lactic dehydrogenase, or bilirubin was detected in the aminoglycoside and control groups. Alkaline phosphatase increased significantly in the aminoglycoside group (average elevation of 28 +/- 16 units/L on day 6), but no patient had an elevation greater than twice the upper limit of the normal range. We conclude that the abnormality in liver enzymes during aminoglycoside therapy is a mild elevation in alkaline phosphatase, probably with no clinical significance.
Abstract: A case of hairy cell leukemia and IgG paraproteinemia is described. Peripheral blood surface marker analysis, serum paraprotein levels and immunoperoxidase stains of bone marrow sections at diagnosis and after 7 months of interferon treatment suggested the existence of two unrelated pathological B cell clones: one composed of malignant hairy cells and the other secreting the paraprotein. Previously reported cases of hairy cell leukemia with paraproteins are reviewed and our patient's contribution to the understanding of this association is stressed.
Abstract: A 22 year old woman presented with lupus nephritis, hypertension, and intractable nephrotic syndrome. Albumin and furosemide given intravenously was ineffective. Captopril administered in a daily dose of 62.5 mg was associated with a reduction in proteinuria from 28 g/24 hours to 11.5 g/24 hours over 10 weeks, resulting in a weight reduction of 16 kg. This was achieved with relative preservation of renal function. Captopril should be considered in the treatment of intractable proteinuria in patients with lupus nephritis, or when cytotoxic drugs are refused, because of its efficacy and relative safety. Captopril should, however, be used as an adjunct and not as a substitute for standard treatment.
Abstract: We describe a 31-year-old patient with missed abortion, thrombocytopenia, and clinical, laboratory, and radiologic evidence of hepatic infarction. On evaluation, she was found to have the lupus anticoagulant. The association between enhanced thrombosis and the lupus anticoagulant is discussed, and previously reported thrombotic complications are described. The etiology, clinical course, and radiologic features of liver infarction are summarized, and the importance of recognizing and treating this form of hypercoagulability is stressed. To our knowledge, this is the first description of liver infarction associated with the lupus anticoagulant.
Abstract: T cell vaccination against experimental autoimmune disease is herein shown to be mediated in part by anti-ergotypic T cells, T cells that recognize and respond to the state of activation of other T cells. The anti-ergotypic response thus combines with the previously shown anti-idiotypic T cell response to regulate autoimmunity.
Abstract: A 76-year-old patient presenting with leukocytoclastic vasculitis and later diagnosed as having diffuse immunoblastic lymphoma is presented. The clinical data of patients with leukocytoclastic vasculitis and lymphoproliferative disease reported in the literature are summarized. Other diseases associated with this form of vasculitis and the proposed pathogenesis are briefly discussed.
Abstract: A 64-year-old patient with major depression who developed self-induced water intoxication associated with rhabdomyolysis is presented. The possible link between acute hyponatremia and muscle injury is discussed and previous reported cases with this association are reviewed. The importance of recognizing this complication in patients with water intoxication is stressed.
Abstract: A 43 year old patient with Addison's disease secondary to extensive metastases to both adrenal glands is presented. Thirty two previously reported cases are reviewed; in only 13 cases was the diagnosis of Addison's disease confirmed biochemically. Reasons for the apparent rarity of Addison's disease in spite of the frequency of adrenal metastases are discussed. The need to consider the possibility of Addison's disease complicating known malignant disease arising in other tissues is stressed.
Abstract: Twenty fibrositic patients were treated with imipramine 50-75 mg/day. Only two patients responded favourably. Nineteen patients stopped therapy during the initial three-month period: 14 of them due to lack of response, while two of these concomitantly disclosed side effects. The additional five patients stopped therapy mainly due to side effects, while only one of them improved with therapy. One patient, only, improved and adhered to therapy for more than three months.
Abstract: Systolic time interval (STI) measurements were made in 44 patients with coronary artery disease: 38 had regional left ventricular (LV) asynergy, and the remaining 6 had normal ventricular contraction patterns on left ventricular angiography. There was a significant correlation between both the preejection period (PEP) (r = 0.70) and the PEP/LVET (LV ejection time) ratio (r = 0.66), with the extent of regional ventricular dysfunction measured quantitatively on the left ventricular angiogram (P less than 0.001). A PEP/LVET ratio greater than 0.50 was associated with ventricular asynergy involving more than 40% of the LV circumference at end diastole. STI measurements also correlated with ejection fraction but not with ventricular end diastolic pressure nor with the number of obstructed coronary arteries.
