Biomedical subjects

J Zhang

Publications and source records attributed to J Zhang.

At least 19 recordsLinked to original sources

PubMed1995

In vivo clonotypic regulation of human myelin basic protein-reactive T cells by T cell vaccination.

Autoreactive T cells specific for myelin basic protein (MBP) are implicated in the pathogenesis of multiple sclerosis. The mechanism by which MBP-reactive T cells are regulated in vivo remains unknown, but is thought to involve the clonotypic regulatory network that can be induced by immunization with attenuated T cells and TCR peptides. We reported previously that immunization of multiple sclerosis patients with irradiated MBP-reactive T cells (T cell vaccination) induced T cell responses to the immunizing clones, resulting in a clonal depletion of circulating MBP-reactive T cells. In this study, we demonstrated that in the majority of the recipients, MBP-reactive T cells remained undetectable in circulation over a period of 1 to 3 yr after vaccination, while they reappeared in some individuals (three of nine), coinciding with clinical exacerbation. The reappearing MBP-reactive T cells were found to originate from clonal origins different from those of T cells persisting before immunization, suggesting a shift of the T cell repertoire to other determinants of MBP. The immunization induces predominantly CD8+ regulatory T cells capable of lysing the immunizing clones in a clonotype-specific manner. The T cell responses induced by immunization were restricted to the immunizing clones and did not affect MBP-reactive clones not used for immunization. Our data further suggest that different hypervariable regions of the TCR may be involved in the observed clonotypic interaction. This study provides useful information for designing future clinical trials using T cell vaccination and other TCR-based therapeutic strategies.

Amino Acid Sequence↗

PubMed1995

Hematopoietic cell phosphatase associates with erythropoietin (Epo) receptor after Epo-induced receptor tyrosine phosphorylation: identification of potential binding sites.

Erythropoietin (Epo) binding to its receptor (EpoR) induces tyrosine phosphorylation in responsive cells and this ability is required for a mitogenic response. One of the substrates of tyrosine phosphorylation is the Epo receptor (EpoR). The carboxyl region of EpoR cytoplasmic domain is required for EpoR phosphorylation and has been shown to negatively affect the response to Epo both in vivo and in cell lines. Hematopoietic cell phosphatase (HCP) has also been hypothesized to negatively regulate erythropoiesis, based on the hypersensitivity to Epo of erythroid lineage cells in moth-eaten mice that genetically lack HCP. In the studies presented here, we show that HCP binds the tyrosine phosphorylated Epo receptor through the amino-terminal src-homology 2 (SH2) domain of HCP. Using a series of phosphotyrosine-containing peptides, potential HCP binding sites in the cytoplasmic domain of the EpoR are identified. The results support the concept that, after Epo stimulation, phosphorylation of EpoR provides a docking site for HCP in the receptor complex. Recruitment of HCP to the complex and its subsequent dephosphorylation of substrates and/or associated kinases may be important to mitigate the ligand-induced mitogenic response.

Amino Acid Sequence↗

PubMed1995

Clonal expansion of myelin basic protein-reactive T cells in patients with multiple sclerosis: restricted T cell receptor V gene rearrangements and CDR3 sequence.

Myelin basic protein (MBP)-reactive T cells are thought to play an important role in the pathogenesis of multiple sclerosis (MS). In some patients with MS, these autoreactive T cells display a limited heterogeneity in their epitope recognition and T cell receptor (TCR) variable (V) gene usage. These individual-dependent properties of MBP-reactive T cells have led to the speculation that they may represent clonal expansion in vivo in some MS patients. In the present study, 51 MBP-reactive T cell clones derived from patients with MS and healthy individuals were examined for their epitope recognition and the TCR V alpha and V beta gene rearrangements. The V gene junctional region sequences of identified alpha and beta genes were further analyzed to probe their clonal origins, as the sequences are unique for individual clones. Our data showed that 26 clones derived from nine patients with MS shared a predominant reactivity to the immunodominant regions of MBP, 84-102, 110-129 and 143-168, and used various TCR V alpha and V beta rearrangements. The V gene usage of the clones was restricted to certain V alpha V beta combination(s) in a given MS patient, but varied among different patients. The sequence analysis revealed that the clones generated from a given patient shared a limited or a single junctional region sequence pattern(s), indicating their oligoclonal or monoclonal origin(s). In contrast, 25 MBP-reactive T cell clones derived from normal individuals exhibited unfocused epitope recognition and V gene usage. Thus, the limited heterogeneity of MBP-reactive T cells in their structural and functional characteristics reflects their clonal expansion in vivo in some patients with MS.

Amino Acid Sequence↗

PubMed1995

Superantigen reactivity of gamma delta T cell clones isolated from patients with multiple sclerosis and controls.

gamma delta T cells have been implicated as playing a role in the demyelinating processes of multiple sclerosis (MS). However, the nature of the ligands which lead to activation and accumulation of gamma delta T cells in the brain lesions remains unknown. This study was undertaken to examine whether gamma delta T cells derived from cerebrospinal fluid and blood of MS patients could be stimulated by bacterial superantigens: staphylococcal enterotoxins A and B and toxic shock syndrome toxin-1. A panel of 16 gamma delta T cell clones isolated from MS patients and controls was found to react with the superantigens used at a nanogram range and displayed specific cytotoxic activity toward target cells pulsed with the corresponding superantigens. The responses of the gamma delta T cell clones did not require MHC-matched accessory cells and were not blocked by antibodies to the MHC molecules, suggesting a non-MHC restricted interaction. The superantigen reactivity was associated with both V delta 2+/V gamma 2+ and V delta 1+/V gamma 1+ subsets, reportedly found in the MS lesions. Our data suggest an alternative pathway which may account for gamma delta T cell activation in MS.

B-Lymphocytes↗

PubMed1995

Activation and clonal expansion of human myelin basic protein-reactive T cells by bacterial superantigens.

Autoreactive T cells specific for myelin basic protein (MBP) are part of the normal T cell repertoire and are present both in patients with multiple sclerosis (MS) and healthy individuals. There is evidence suggesting in vivo activation and persistent clonal expansion of MBP-reactive T cells in MS. This study was undertaken to investigate the potential role of bacterial superantigens (SA) in the activation of MBP-reactive T cells. Twenty-seven MBP-reactive T cell clones generated from 10 MS patients and one normal individual were examined for reactivity to SA, in association with their T cell receptor V beta gene usage. The majority of the clones responded to at least one of the SA tested, staphylococcal enterotoxins (SEA and SEB) and toxic shock syndrome toxin-1 (TSST-1). The clones reactive to SEA and SEB expressed various V beta genes while T cell reactivity to TSST-1 correlated with the V beta 2 expression. Furthermore, circulating MBP-reactive T cells could be expanded from lymphocyte cultures primarily exposed to respective SA in more than 50% of MS patients and normal individuals tested. However, activation and expansion of circulating MBP-reactive T cells by SA was not directly associated with the disease. This study lends support to the potential role of SA in the activation of MBP-reactive T cells and suggests that an altered regulatory mechanism may account for further expansion and persistence of MBP-reactive T cells in MS.

Adult↗

PubMed1995

Nitric oxide synthase, immunophilins and poly(ADP-ribose) synthetase: novel targets for the development of neuroprotective drugs.

During ischemic stroke, massive neural damage occurs due to excess release of glutamate which acts mainly through N-methyl-D-aspartate (NMDA) receptors. Activation of the NMDA receptor stimulates nitric oxide (NO) production by NO synthase (NOS). NO mediates glutamate neurotoxicity as inhibitors of NOS prevent neuronal death. FK506, an immunosuppressant drug, binds to FK506 binding protein (FKBP). One target of the FK506/FKBP complex is the calcium/calmodulin-dependent protein phosphatase calcineurin, whose activity is inhibited upon interaction with FK506/FKBP. FK506 treatment increases phosphorylation level of calcinurin substrates including NOS. As a potent neuroprotective agent in vitro and in vivo, FK506 increases NOS phosphorylation and decreases NO production. NO activates poly(ADP-ribose) synthetase (PARS), a nuclear enzyme that synthesizes poly(ADP-ribose) from NAD. Prolonged activation of PARS depletes NAD and lowers cellular energy levels. Inhibition of PARS also prevents NO toxicity. NOS inhibitors, immunosuppressants and PARS inhibitors may be useful agents to prevent neuronal damage during stroke.

Animals↗

PubMed1995

Effects of trauma on leukocyte intercellular adhesion molecule-1, CD11b, and CD18 expressions.

BACKGROUND: During traumatic injury, a multitude of events, including ischemia, may cause leukocyte adhesion and margination. In this study, alterations of surface receptors involved in leukocyte adhesion were studied in traumatized patients. In an attempt to discern the role of hypoxia, additional experiments were conducted in which normal human leukocytes were subjected to hypoxic stress in vitro. METHODS: Venous blood was obtained from 10 trauma patients within 2 hours of blunt injury (mean Injury Severity Score of 17 +/- 8) and from 8 normal volunteers (controls). Leukocytes were isolated from patients and controls. To assess the effect of hypoxia, normal leukocytes were placed in hermetically sealed environments containing 100% nitrogen. All leukocytes were labeled with phycoerythrin- or fluorescein-bound monoclonal antibodies to intercellular adhesion molecule-1 (ICAM-1), or to integrins CD18 and CD11b. Receptor concentration was measured by flow cytometry. Results were expressed as percentage of receptor-positive cells (%) and mean fluorescence channel units, which directly correlate with monoclonal antibody cell surface density. Significance of differences was tested by analysis of variance/Kruskal-Wallis test. RESULTS: Compared with the normal controls, circulating leukocytes obtained from traumatized patients showed decreased expression of ICAM-1, CD11b, and CD18 2 hours after injury. In contrast, normal leukocytes exposed to hypoxic stress in vitro exhibited a marked increase in CD11b and CD18 expression and no change in ICAM-1 expression. CONCLUSIONS: Leukocytes obtained from traumatized patients showed a significant decrease in cell surface expression of adhesion receptors. This phenomenon is unlikely to be a direct consequence of hypoxia alone, because exposure to isolated hypoxia in vitro actually increased expression of CD11b and CD18.

Adult↗

PubMed1995

Nitric oxide synthase inhibition and extracellular glutamate concentration after cerebral ischemia/reperfusion.

BACKGROUND AND PURPOSE: Transient cerebral ischemia in rats results in selective loss of neuronal viability, eg, hippocampal CA1 neurons. The neurochemical variables responsible for this selective vulnerability to ischemia/reperfusion (IR) appear to involve excitatory amino acids. In brain IR, excitatory amino acid toxicity may be modulated by endogenous nitric oxide (NO.) gas. To investigate NO. in global brain IR, we measured the effects of NO. synthase (NOS) inhibition on interstitial excitatory amino acids in rats. Changes in postischemic cerebral blood flow and blood-brain barrier function also were evaluated. METHODS: Forebrain ischemia was produced by systemic hypotension and occlusion of both carotid arteries for 15 minutes. Blood flow was restored for 60 minutes by unclamping the carotids and reinfusing with blood. A microdialysis probe was placed into the cortex and hippocampus using a stereotaxic device. Interstitial glutamate concentration was measured during IR with high-performance liquid chromatography. A competitive NOS inhibitor, N omega-nitro-L-arginine methyl ester (L-NAME), was given intraperitoneally 30 minutes before ischemia in doses of 1, 4, and 20 mg/kg. Changes in cerebral blood flow and blood-brain barrier during IR were determined using laser-Doppler flowmetry and microdialysis with sodium fluorescein. RESULTS: Glutamate in the dialysate during IR increased transiently 10-fold and returned to baseline levels by 30 minutes of reperfusion. Animals treated with L-NAME 30 minutes before ischemia also showed increases in glutamate concentration during ischemia, but glutamate remained elevated during reperfusion. The increase in glutamate concentration during reperfusion caused by L-NAME was prevented by L-arginine. The administration of L-arginine and L-NAME together decreased extracellular glutamate concentration during ischemia. Cerebral blood flow decreased to about 5% of baseline values during ischemia but increased approximately fourfold relative to control values on reperfusion. The hyperemic responses after ischemia were not different between IR groups treated with or without L-NAME. Brain ischemia increased the permeability of the blood-brain barrier to fluorescein; however, this change was attenuated by L-NAME administration at 20 mg/kg. CONCLUSIONS: NOS inhibition did not attenuate extracellular glutamate accumulation during ischemia and increased its concentration on reperfusion. The elevated glutamate concentration after IR in L-NAME-treated rats did not appear to be due to either a decrease in cerebral blood flow response after ischemia or increases in local blood-brain barrier permeability. For the most part, the blood-brain barrier was spared in the immediate postischemic period by L-NAME treatment. These data suggest that NO. production may oppose synaptic excitatory amino acid accumulation and presumably excitotoxicity during IR.

Amino Acid Oxidoreductases↗

PubMed1995

Motion detectors and motion segregation.

The response of motion detectors necessarily confound image velocity with image structure. In particular, even a rigidly moving image (with a uniform velocity field) will give rise to non-uniform detector responses. A mathematical framework has been proposed on how to intrinsically compare motion detectors' responses so that their differences will reflect the true differences in image velocity (Zhang and Wu, Proc. Natl. Acad. Sci. USA 87, 7819-7823, 1990). Here, this notion of 'intrinsic differentiation' was implemented by introducing a gamma-matrix determined by the image spatial gradients. The perceptual phenomenon of random-dot motion segregation was successfully simulated.

Humans↗

PubMed1995

Steroid hormone receptors in astrocytic neoplasms.

The presence of specific steroid hormone-binding receptors has been correlated with the clinical response to hormonal therapy in a number of different neoplasias, including breast and prostate cancer. In this article, we investigated the expression of the androgen, estrogen, glucocorticoid, and progesterone receptor messenger ribonucleic acid (mRNA) and protein in a number of astrocytic neoplasms of various histological grades. Androgen and glucocorticoid receptor mRNA were detected in all astrocytic neoplasms examined, regardless of histological subtype. In contrast, progesterone receptor mRNA was observed more frequently in high-grade tumors than in low-grade tumors. Estrogen receptor mRNA was undetectable in all astrocytic tumors examined. These studies suggest a possible adjunct clinical use of hormonal therapy for the treatment of astrocytomas. Specific antagonists and agonists may allow the modulation of the growth of these tumors. Development of this body of knowledge may lead to the development of better treatment for these aggressive tumors.

Adolescent↗

PubMed1995

Tissue distribution of cocaine methyl esterase and ethyl transferase activities: correlation with carboxylesterase protein.

The tissue distribution of cocaine methyl esterase and ethanol-dependent ethyl transferase activities was determined in the rat and compared to the tissue distribution of three distinct non-specific hydrolases. Rates of formation of benzoylecgonine from cocaine and cocaethylene from ethanol and cocaine were measured in serum and tissue homogenate-supernatants of the brain, heart, kidney, liver, lung and spleen. The tissue distribution of three nonspecific esterases, A, B and C, was defined by nondenaturing gel electrophoresis and measuring the hydrolysis of 4-methylumbelliferyl acetate in the gels. Immunoreactive protein was localized by using Western blot analysis with polyclonal rabbit antihuman liver cocaine methyl esterase antibody after denaturing and nondenaturing gel electrophoresis. The rat liver, lung, kidney and heart exhibited cocaine methyl esterase and ethyl transferase activities and immunoreactive protein. The brain had cocaine methyl esterase activity but no ethyl transferase activity; neither activity was found in serum or spleen. The dominant immunoreactive bands in the liver, lung, kidney and heart comigrated with the 59 kD band of purified human liver cocaine methyl esterase. The rat liver, lung and kidney exhibited a band of nonspecific esterase activity that migrated with purified human liver cocaine methyl esterase and rat hydrolase A. These observations suggest that rat hydrolase A is similar to human cocaine methyl esterase. The lack of straight forward correlation between cocaine methyl esterase activity and immunoreactive protein and nonspecific esterase activity suggests that more than one enzyme catalyzes the hydrolysis of cocaine to benzoylecgonine in the rat.

Animals↗

PubMed1995

Suppression of insulitis in non-obese diabetic (NOD) mice by oral insulin administration is associated with selective expression of interleukin-4 and -10, transforming growth factor-beta, and prostaglandin-E.

Oral administration of autoantigens suppresses development of autoimmunity in several animal models, and is being tested in clinical trials in patients with autoimmune diseases such as multiple sclerosis and rheumatoid arthritis. Non-obese diabetic (NOD) mice spontaneously develop insulin-dependent diabetes mellitus at 15 to 20 weeks of age, after mononuclear cell (MNC) infiltration of the pancreatic islets of Langerhans and destruction of insulin-producing beta cells. We have previously shown that oral administration of insulin suppresses insulitis and development of diabetes in the NOD mouse. Oral insulin has no metabolic effect on blood glucose. Oral insulin mediates its effect through a T cell-dependent mechanism as shown by adoptive transfer and T cell depletion experiments, but the mechanisms responsible have not been fully explored. We now report a serial analysis of the cells and cytokines associated with development of diabetes in NOD mice, and contrast this with the findings in animals fed equine insulin or a control protein (ovalbumin). Animals were fed 1 mg twice a week for 5 weeks, beginning at 5 weeks of age. Marked insulitis in naive or ovalbumin-fed NOD mice occurred at 10 weeks, at which time a dense peri-islet and intra-islet MNC infiltration was observed. Immunohistological studies using monoclonal antibodies showed that infiltrating MNC consisted mainly of CD4+ T cells ( > 75% of leukocytes) plus smaller numbers of macrophages and CD8+ T cells. These cells displayed evidence of immune activation with expression of receptors for interleukin-2 (IL-2R) plus Th1 cytokines; dense labeling for IFN-gamma and tumor necrosis factor-alpha, plus lesser amounts of IL-2, was observed. MNC lacked labeling for IL-4, IL-10, prostaglandin-E, or transforming growth factor-beta. By contrast, at 10 weeks, pancreatic tissues from NOD mice fed insulin showed considerably less insulitis, and the residual MNC, although still largely CD4+ T cells plus macrophages, showed dense labeling for IL-4, IL-10, prostaglandin-E, and transforming growth factor-beta and an absence of IL-2, IFN-gamma or tumor necrosis factor-alpha Taken together with our previous findings, these data indicate that oral administration of insulin affects the development of diabetes in NOD mice through the generation of cells that elaborate immunoregulatory cytokines within the target organ and shift the balance from a Th1 to a Th2 pattern of cytokine expression.

Administration, Oral↗

PubMed1995

[Study on determination of gentamycin in serum by enhanced chemiluminesent immunoassay based on immobilized antibody and biotin-avidin system].

Gentamycin was determined by competition with biotin labeled gentamycin in the presence of an immobilized antibody to gentamycin. Microcrystalline cellulose was first coupled with sheep anti-rabbit antibody, then the anti-gentamycin antibody was conjugated and the competition reaction conducted. After separation, HRP-avidin was added to the precipitation and the amount of HRP conjugate determined by enhanced chemiluminescene. The limit of detection for gentamycin in serum was 63-78 ng/tube and the average recovery of gentamycin 103%. The correlation coefficient of the log-log regression equation. Magnitude of r was 0.991 +/- 0.006.

Animals↗

PubMed1994

Regulation of the transcription of a cluster of Bacillus subtilis spore coat genes.

The pattern of transcription has been examined for a cluster of genes encoding polypeptides some or all of which are assembled into a cross-linked component of the Bacillus subtilis spore coat. Three promoters, designated PVWX, PX and PYZ, were indicated by reverse transcriptase mapping. On the basis of Northern hybridization, it appeared that the cotV, W and X genes were transcribed as a polycistronic mRNA from PVWX as well as a monocistronic cotX mRNA from Px. The cotY and cotZ genes are cotranscribed from the PYZ promoter with a smaller cotY mRNA resulting from premature termination or RNA processing. All four transcripts were synthesized late during sporulation and were not produced in mutants lacking sigma K, which directs RNA polymerase to transcribe genes in the mother-cell compartment of sporulating cells. The DNA-binding protein GerE, which affects transcription of many genes in the mother cell during the late stages of sporulation, was also shown to be involved. There was essentially no cotX mRNA in a gerE mutant and the amounts of cotVWX, cotYZ and cotY mRNAs were somewhat reduced. In vitro run-off transcription studies with sigma K RNA polymerase and GerE confirmed the presence of the three promoters, and directly showed that GerE was necessary for transcription from PX as well as enhanced transcription from the PVWX and PYZ promoters. The DNase I footprints of GerE for all three promoters were immediately upstream of the -35 regions. These GerE binding sites were compared to those in other GerE-responsive promoters and a larger consensus sequence for GerE binding was recognized. This complex transcriptional pattern of the cotVWXYZ cluster is probably necessary to ensure that an optimal amount of each protein is made for the assembly of the spore coat.

Bacillus subtilis↗

PubMed1994

Clonal expansion and persistence of human T cells specific for an immunodominant myelin basic protein peptide.

TCR rearrangements were used to probe the clonal origin of myelin basic protein (MBP)-reactive T cells from patients with multiple sclerosis (n = 7) and normal subjects (n = 3). The majority of MBP-specific T cell lines were specific for the immunodominant MBP(84-102) and MBP(143-168) peptides and were restricted by HLA-DR molecules. In two patients with the DR2 haplotype, the T cell response to MBP was focused on the MBP(84-102) peptide. In both patients, in vivo expanded population(s) (three expanded populations in the first patient, one expanded population in the second patient) dominated the response to the MBP(84-102) peptide. Two MBP(84-102)-specific T cell clones from a normal subject with the DR2 haplotype were also found to have identical TCR sequences. Clonality was proven by demonstrating that independent clones had identical TCR alpha- and TCR beta-chain sequences as well as identical sequences of a TCR gamma-chain or of a second TCR alpha-chain rearrangement. Repeated analysis of one patient after 13 mo demonstrated that the three expanded clones had persisted in vivo. A representative of one of the expanded clones was again obtained after 31 mo by IL-2 stimulation suggesting that this clone was activated in vivo. These data suggest that the response to human MBP is dominated in at least some subjects by expanded clones that may persist in vivo for relatively long periods of time.

Adult↗

PubMed1994

Effect of local infusion of glutamate analogues into the nucleus accumbens of rats: an electrochemical and behavioural study.

In vivo voltammetry at electrochemically pretreated carbon fibre electrodes was used to investigate the effect of local infusion of glutamate analogues on dopamine (DA) release in rat nucleus accumbens. Infusion of a low dose of NMDA or AMPA (1 mM/0.2 microliter), but not L-glutamate or kainate, was followed a few minutes later by a large but short-lived increase in the extracellular concentration of DA. The involvement of spreading depression was indicated since this response could be repeated only after a short refractory period, and the response magnitude did not seem to be dependent on the dose infused. Furthermore, the increase in DA release was accompanied by a marked negative shift in brain field potential and a similar increase in release could be induced by local infusion of K+. The infusion of NMDA, AMPA or kainate was followed by behavioural activation of the animals but not convulsions. The behavioural response induced by NMDA was dose-dependently reduced by haloperidol, which suggests the involvement of a DA-dependent mechanism in this effect. Co-infusion of the DA transport inhibitors, nomifensine or GBR 12909, failed to alter the DA response to NMDA, while this response was completely blocked by co-infusion of tetrodotoxin or pretreatment with reserpine. It is evident from this study that local infusion of NMDA or AMPA may induce spreading depression in rat nucleus accumbens and that this condition is associated with a vast release of DA and behavioural activation.

Animals↗

PubMed1994

Correction of accelerated autoimmune disease by early replacement of the mutated lpr gene with the normal Fas apoptosis gene in the T cells of transgenic MRL-lpr/lpr mice.

MRL-lpr/lpr mice develop a generalized autoimmune disease which includes increased autoantibody production, glomerulonephritis, and development of lymphadenopathy. The lpr genetic defect has been identified as a mutation in the Fas apoptosis gene that results in low expression of Fas mRNA. To determine the significance of the lpr mutation and T cells in the development of the autoimmune disease, we constructed transgenic MRL-lpr/lpr mice using a full-length murine Fas cDNA under the regulation of the T-cell-specific CD2 promoter and enhancer. Here we show that the early correction of the lpr gene defect in T cells eliminates glomerulonephritis and development of lymphadenopathy and decreases the levels of autoantibodies. In this model, early correction of the lpr defect in T cells is sufficient to eliminate the acceleration of autoimmune disease even in the presence of B cells and other cells that express the mutant lpr gene.

Animals↗

PubMed1994

Increased frequency of interleukin 2-responsive T cells specific for myelin basic protein and proteolipid protein in peripheral blood and cerebrospinal fluid of patients with multiple sclerosis.

Equal numbers of CD4+ T cells recognizing myelin basic protein (MBP) and proteolipid protein (PLP) are found in the circulation of normal individuals and multiple sclerosis (MS) patients. We hypothesized that if myelin-reactive T cells are critical for the pathogenesis of MS, they would exist in a different state of activation as compared with myelin-reactive T cells cloned from the blood of normal individuals. This was investigated in a total of 62 subjects with definitive MS. While there were no differences in the frequencies of MBP- and PLP-reactive T cells after primary antigen stimulation, the frequency of MBP or PLP but not tetanus toxoid-reactive T cells generated after primary recombinant interleukin (rIL-2) stimulation was significantly higher in MS patients as compared with control individuals. Primary rIL-2-stimulated MBP-reactive T cell lines were CD4+ and recognized MBP epitopes 84-102 and 143-168 similar to MBP-reactive T cell lines generated with primary MBP stimulation. In the cerebrospinal fluid (CSF) of MS patients, MBP-reactive T cells generated with primary rIL-2 stimulation accounted for 7% of the IL-2-responsive cells, greater than 10-fold higher than paired blood samples, and these T cells also selectively recognized MBP peptides 84-102 and 143-168. In striking contrast, MBP-reactive T cells were not detected in CSF obtained from patients with other neurologic diseases. These results provide definitive in vitro evidence of an absolute difference in the activation state of myelin-reactive T cells in the central nervous system of patients with MS and provide evidence of a pathogenic role of autoreactive T cells in the disease.

Adult↗