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T Sakane

Publications and source records attributed to T Sakane.

At least 73 records · Page 4Linked to original sources
PubMed1997

Characterization of T cells specific for an epitope of human 60-kD heat shock protein (hsp) in patients with Behcet's disease (BD) in Japan.

BD is prevalent in the area of the Silk Route. It has been shown that hsp are involved in the T cell activation in patients with BD in the UK, where this disease has developed sporadically. We have thus examined whether the T cell response to the hsp-derived peptides may be induced in patients with BD in Japan, an east pole of the Silk Route. As with patients in the UK, the human 60-kD hsp peptide 336-351 also yielded vigorous proliferation of T cells in Japanese patients with BD, but neither in normal subjects nor in patients with rheumatoid arthritis (RA); there was significant association between proliferation by this peptide and the presence of ocular lesion, but not any other symptoms of BD. To clarify whether the peptide stimulates T cells as a polyclonal activator, a specific antigen or a superantigen-like substance, we analysed T cell receptor (TCR) usage of responding T cells by means of MoAbs specific for TCR Vbeta subfamily and polymerase chain reaction (PCR)-single-strand conformation polymorphism (SSCP)-based technique. We found that T cells with certain TCR Vbeta subfamilies (including Vbeta5.2-3, 8, 13.6, 18, 21.3) were increased in circulation and responded to the hsp peptide in an antigen-specific fashion. In addition, TCR Vbeta gene-amplified products of freshly isolated T cells of patients with BD formed several bands in the PCR-SSCP analysis; some of them became prominent after stimulation with the peptide. This suggests that T cells in patients with this disease have already been expanded oligoclonally in vivo, which may be a result of stimulation by triggering antigens, including the hsp peptide. In addition, hsp peptide stimulation induced proinflammatory cytokine mRNA expression in peripheral blood mononuclear cells, including IL-8, tumour necrosis factor-alpha (TNF-alpha) and TNF-beta in eight out of eight patients studied. Taken together, the results suggest that hsp antigen may play a role in the pathogenesis of BD, not only in the area of the Silk Route, but also outside the Silk Route area.

Adult↗
PubMed1997

Rescue by cytokines of apoptotic cell death induced by IL-2 deprivation of human antigen-specific T cell clones.

The control of cell survival and cell death is of central importance in tissues with high cell turnover such as the lymphoid system. We have examined the effect of cytokines on IL-2 deprivation-induced apoptosis of human antigen-specific T helper clones with different cytokine production profiles. We found that IL-2, interferon-alpha (IFN-alpha), and IFN-beta inhibited IL-2 deprivation apoptosis in Th0, Th1, and Th2 clones. We also found that IL-2 protects T cell clones from IL-2 deprivation apoptosis accompanying active proliferation and enhanced expression of P53, Rb and Bcl-xL proteins. In contrast, IFN-alpha/beta rescued T cell clones from apoptosis without active proliferation, and expression of apoptosis-associated proteins tested so far was unaffected. This may be due to the fact that T cells treated with IL-2 contained those located in S + G2/M phases of the cell cycle, whereas the vast majority of T cells treated with IFN-alpha/beta were located in G0/G1 phase. IFN-alpha/beta specifically induced tyrosine phosphorylation and translocation into nucleus of signal transducers and activators of transcription (STAT) 2 protein in the T cell clones. In addition, over-expression of STAT2 by transfection of the cDNA prevented apoptosis of the T cell clones. Our present study shows that IFN-alpha and -beta mediate anti-apoptotic effect through other pathways than that of IL-2 in growth factor deprivation apoptosis.

Animals↗
PubMed1997

Therapeutic effects of preferential induction of mite-specific T helper 0 clones.

The predominance of Th2 cytokine-secreting pattern in allergic asthma has been known as a cause and an accelerating factor, and Th1 suppresses these allergic phenomena, but the role of Th0 clones is obscure. Because Th1/Th2 differentiation has been determined by cytokine environment, we investigated how mite-specific helper T cells stimulated in different cytokine environments actually influenced IgE and IgG4 synthesis, which are known to be regulatory immunoglobulins for allergic response. Th0 clones, which were mainly established in the presence of IL-12, provided a great deal of help for IgG4 and IgG1 synthesis, but did not provide help for IgE synthesis, whereas Th2 clones helped IgE synthesis prominently, and IgG4 and IgG1 synthesis marginally. These characteristics of Th0 clones were also true for Th0 clones obtained from patients who were successfully treated with desensitization therapy. Furthermore, the differences in helper activity between Th0 and Th2 clones were not ascribed solely to soluble factors. These data indicate that IgE and IgG4 synthesis is differentially regulated by antigen-specific T cells, and that conversion or selection from Th2 to Th0 by the addition of IL-12 may exhibit therapeutic effects.

Adult↗
PubMed1997

Development of pathogenic anti-DNA antibodies in patients with systemic lupus erythematosus.

The anti-DNA response is a hallmark of systemic lupus erythematosus (SLE). The precise mechanisms leading to anti-DNA antibody (Ab) production remain to be studied. Nonetheless, it is becoming clear that anti-DNA Abs cause inflammatory lesions not only via deposition of circulating immune complexes (IC) consisting of anti-DNA Ab and antigens (Ags), but also via in situ IC formation by cationic anti-DNA Abs. It is intriguing that cationic anti-DNA Abs are encoded by a unique germline Vkappa gene, A30, which encodes an extraordinary cationic light chain, whereas somatic mutations did not induce a cationic shift of electrical charge in human lupus nephritis, suggesting that the usage of a specific germline gene may confer the cationic charge (or pathogenicity) on anti-DNA Abs and that somatic mutations induce the affinity maturation of Abs. Whether cationic anti-DNA Abs will develop depends at least partly on the presence or absence of the germline A30 gene, since patients who lack this gene in the germline Vkappa repertoire did not develop severe lupus nephritis. Receptor editing, a mechanism for changing the affinity of the B cell Ag receptor [surface immunoglobulin (Ig) receptor] to avoid self-reactivity actually seems defective in patients with SLE because normal B cells edited the A30 gene, whereas SLE B cells express A30 mRNA. Thus, along with the importance of somatic mutations, polymorphisms of Ig Vkappa locus, and genetic predisposition, the failure of receptor editing may contribute to the development of pathogenic anti-DNA responses in humans.

Antibodies, Antinuclear↗
PubMed1997

Role of gammadelta T lymphocytes in the development of Behçet's disease.

Phenotypic and functional properties of gammadelta T cells, which play an important role in mucocutaneous immunity, were examined to elucidate whether immunological abnormality in Behcet's disease may be related to a specific T cell population. We found that CD45RA+ Vgamma9+ Vdelta2+ gammadelta T cells, which constitute a minor population of gammadelta T cells in healthy individuals, were increased in number in Behçet's disease irrespective of disease activity. This CD45RA+ subset of gammadelta T cells in the active, but not inactive, phase of this disease expressed IL-2Rbeta and HLA-DR, suggesting that they are activated in vivo in active Behçet's disease. In addition, the CD45RA+ gammadelta T cells produced extreme amounts of tumour necrosis factor and contained perforin granules. These data indicate that a phenotypically distinct subset of gammadelta T cells, CD45RA+ CD45RO- Vgamma9+ Vdelta2+, may contribute to immunological abnormalities which may lead to complexity of pathophysiology in Behçet's disease.

Adult↗
PubMed1997

New perspective on Behçet's disease.

There are many distinct differences between Behçet's disease of Silk Route and that of outside Silk Route; genetic factors, role of neutrophils, and severity of this disease. We have thus emphasized that we prefer the term "Behçet's syndrome" rather than "Behçet's disease". In this chapter, Behçet's disease seen along the Silk Route will be mainly discussed. HLA-B51 molecules themselves may be responsible, at least in part, for the neutrophil hyperfunction in Behçet's disease; a significant correlation was observed between the neutrophil hyperfunction and the possession of HLA-B51 phenotype, regardless of the presence of the disease, in both humans and HLA-B transgenic mice. T cells in this disease, proliferated vigorously in response to a specific peptide of human heat shock protein (HSP)-60; however, T cells from normal subjects or patients with rheumatoid arthritis, did not. This peptide has the amino acid sequence of 336-351 of human HSP-60, which is similar, but not identical to specific peptide of mycobacterial HSP-65. We have further analyzed T cell receptor (TCR) usage of HSP-responsive T cells by means of TCR V beta subfamily specific monoclonal antibodies and polymerase chain reaction and single strand conformation polymorphism-based technique. We found that T cells with specific TCR V beta subfamilies proliferated and increased in number in response to the peptide by an antigen-specific fashion. The result of recurrent exposure to the HSP may break the tolerance to self-HSP, and provoke T cell responses to self- and microbial-HSP. Such T cells produced Th1-like proinflammatory and/or inflammatory cytokines. This leads to tissue injury, possibly via delayed-type hypersensitivity reaction, macrophage activation, and activation and/or recruitment of neutrophils. Our data shed a new light on the autoimmune nature of Behçet's disease; a novel multistep molecular mimicry mechanisms may induce and/or exacerbate Behçet's disease by bacterial antigens that activate T cells previously educated by self-peptides of HSP. This would lead to positive selection of autoreactive T cells in this disease.

Animals↗
PubMed1997

Etiopathology of Behçet's disease: immunological aspects.

Behçet's disease is recognized as a systemic inflammatory disease of unknown etiology. The disease has a chronic course with periodic exacerbations and progressive deterioration. Previous reports have shown at least three major pathophysiologic changes in Behçet's disease; excessive functions of neutrophils, vasculitis with endothelial injuries, and autoimmune responses. Many reports suggested that immunological abnormalities and neutrophil hyperfunction may be involved in the etiology and the pathophysiology of this disease. HLA-B51 molecules by themselves may be responsible, in part, for neutrophil hyperfunction in Behçet's disease. T cells in this disease proliferated vigorously in response to a specific peptide of human heat shock protein (hsp) 60 in an antigen-specific fashion. T cells reactive with self-peptides produced Th1-like proinflammatory and/or inflammatory cytokines. This leads to tissue injury, possibly via delayed-type hypersensitivity reaction, macrophage activation, and activation and/or recruitment of neutrophils. These data shed new light on the autoimmune nature of Behçet's disease; molecular mimicry mechanisms may induce and/or exacerbate Behçet's disease by bacterial antigens that have activated T cells which are reactive with self-peptide(s) of hsp. This would lead to positive selection of autoreactive T cells in this disease.

Behcet Syndrome↗
PubMed1997

[Monoclonal antibodies for treating autoimmune diseases].

Monoclonal antibodies (mAbs) directed to selected cell surface antigens, cytokines and their receptors, and adhesion molecules have been shown to inhibit autoimmune responses in preclinial animal models. Therapeutic trials using the chimeric or humanized mAbs have already been undergoing in patients with rheumatoid arthritis (RA). Effects of anti-CD4 mAb are controversial, but anti-TNF-alpha mAb reveals encouraging results. Although it is too early to determine the efficacy, mAbs are new hopeful therapeutic strategies for autoimmune diseases.

Animals↗
PubMed1997

Mechanisms of KE298, 2-acetylthiomethyl-3-(4-methylbenzoyl) propionic acid, to suppress abnormal synovial cell functions in patients with rheumatoid arthritis.

OBJECTIVE: 2-Acetylthiomethyl-3-(4-methylbenzoyl) propionic acid, KE298, a derivative or propionic acid developed in Japan has been shown to be effective for suppressing disease activity of rheumatoid arthritis (RA) in clinical trials in Japan. It is thus a candidate as a new disease modifying antirheumatic drug (DMARD). We analyzed effects of KE298 on synovial fibroblast-like cells in patients with RA to obtain insight into the clinical application of this medication. METHODS: RA synovial fibroblast-like cells were co-cultured with KE298 at 10(-4)-10(-5) M in the presence or absence of tumor necrosis factor-alpha 2 ng/ml, and their subsequent proliferative responses and proinflammatory cytokine and matrix metalloproteinase (MMP) production at the mRNA and protein levels were measured. Effects of KE298 on MMP-1 gene transcription and AP-1 transcription factor expression of RA synovial cells were studied by chloramphenicol acetyltransferase assay and gel shift assay, respectively. RESULTS: KE298 inhibited proliferation of RA synovial cells, proinflammatory cytokine production, and MMP-1 production mainly by reducing their transcription via downmodulation of AP-1 transcription factor. CONCLUSION: KE298 inhibits aberrant synovial cell functions of patients with RA by downregulating gene transcription, suggesting clinical application and usefulness of this new DMARD.

Antirheumatic Agents↗
PubMed1996

Characterization of a germline Vk gene encoding cationic anti-DNA antibody and role of receptor editing for development of the autoantibody in patients with systemic lupus erythematosus.

We found previously that cationic anti-DNA autoantibodies (autoAbs) have nephritogenic potential and usage of a specific germline Vk gene, A30, has major influences on cationic charge of the autoAb in human lupus nephritis. In the present study, we have characterized A30 germline Vk gene using cosmid cloning technique in patients with SLE. A30 gene locus locates in less than 250 kb from the Ck region, and the cationic anti-DNA mRNA used the upstream Jk2 gene, indicating that cationic anti-DNA mRNA is a product of primary gene rearrangement. By using PCR technique, we found that A30 gene locus in the genome was defective in eight out of nine SLE patients without nephritis. In contrast, all nine patients with lupus nephritis had intact A30 gene. The presence and absence of A30 gene was associated with the development of lupus nephritis or not (P < 0.01, by Fisher's exact test, two-sided). It was thus suggested that absence of functional A30 gene may rescue from developing lupus nephritis in the patients. A30 is reported to be a potentially functional but rarely expressed Vk gene in humans. It is possible that normal B cells edit primarily rearranged A30 gene with autoreactive potentials by receptor editing mechanism for changing the affinity of the B cell Ag receptor to avoid self-reactivity, whereas SLE B cells may have a defect in this mechanism. Indeed, we found that normal B cells edit A30-Jk2 gene in their genome possibly by inversion mechanism, whereas SLE B cells contain rearranged A30-Jk2-Ck gene in the genome and express A30-associated mRNA, suggesting that receptor editing mechanism is also defective in patients with SLE. Our study suggests that polymorphism of Ig Vk locus, and failure of receptor editing may contribute to the development of pathogenic anti-DNA responses in humans.

Adolescent↗
PubMed1996

Transfer of "Pseudomonas riboflavina" (Foster 1944), a gram-negative, motile rod with long-chain 3-hydroxy fatty acids, to Devosia riboflavina gen. nov., sp. nov., nom. rev.

The taxonomic position of "Pseudomonas riboflavina" was studied by 16S rRNA gene sequencing and chemotaxonomic methods. This organism is a gram-negative, strictly aerobic rod and has a DNA guanine-plus-cytosine content of 61.4 mol%; the major isoprenoid quinone is ubiquinone 10, and the unusual cellular fatty acids 3-hydroxytetracosenoic acid (3-OH 24:1) and 3-hydroxyhexacosenoic acid (3-OH 26:1) are the major 3-hydroxy cellular fatty acids. A phylogenetic analysis based on 16S rRNA sequences revealed that "P. riboflavina" IFO 13584T (T = type strain) occupies an independent position in the alpha subclass of the Proteobacteria. On the basis of our data, we propose that "P. riboflavina" IFO 13584T should be transferred to the genus Devosia gen. nov. as Devosia riboflavina sp. nov., nom. rev.

Base Sequence↗
PubMed1996

Emendation of the genus Planococcus and transfer of Flavobacterium okeanokoites Zobell and Upham 1944 to the genus Planococcus as Planococcus okeanokoites comb. nov.

The taxonomic position of Flavobacterium okeanokoites IFO 12536T (T = type strain) was determined by 16S rRNA gene sequencing and chemotaxonomic methods. Phylogenetic evidence derived from a 16S rRNA sequence analysis indicated that F. okeanokoites, which forms rod-shaped cells, belongs to the genus Planococcus, which forms spherical cells. A phylogenetically close relationship was supported by chemotaxonomic characteristics, such as the presence of menaquinone 7 and menaquinone 8 as major isoprenoid quinones, the presence of phosphatidylglycerol, bisphosphatydylglycerol, and phosphatidylethanolamine as cellular polar lipids, and the G + C content of the DNA (46.3 mol%). These data suggest that whether a cell is a rod or a coccus is not a generic criterion. Accordingly, we propose that F. okeanokoites should be transferred to the genus Planococcus and that the description of the genus Planococcus should be emended.

Base Sequence↗
PubMed1996

Quantitative evaluation of the gastrointestinal absorption of protein into the blood and lymph circulation.

In order to investigate the fate of orally administered proteins, the absorption of ovalbumin (OVA) from the gastrointestinal tract into both the blood and lymph circulation was quantitatively evaluated. After oral administration, a significant amount of intact OVA was detected in both the plasma and the lymph fluid by means of a two-site enzyme immunoassay. The extent of absorption into the plasma, calculated from the area under the plasma concentration versus time curve of OVA after oral and intravenous administration, was only 0.007-0.008% of the dose. This value is extremely low compared to that after nasal administration, showing the stronger barrier function of the gastrointestinal tract against the invasion of macromolecular proteins into the body. The extent of absorption into the lymph was dose-dependent (0.0007-0.002% of dose), and a higher dose leads to a higher fraction of OVA absorbed into the lymph. Moreover, it was demonstrated that not only the small intestine but also the stomach can absorb OVA. OVA absorbed from the stomach was transferred almost exclusively to the blood circulation, which suggests different mechanisms and/or routes of absorption between the stomach and the small intestine. In order to improve the low oral absorption, OVA was incorporated in liposomes and administered orally. Although the effect of liposomes was not significant, it increased OVA absorption into both the plasma and lymph by about 2 to 3-fold. It was considered that the liposomes suppressed the enzymatic degradation of OVA and released it slowly in the gastrointestinal tract.

Administration, Intranasal↗
PubMed1996

[Abnormal Fas and Fas ligand expression of lymphocytes in patients with SLE].

Fas and Fas ligand (FasL) have been assigned a pivotal role for establishment and maintenance of peripheral tolerance of immune system, and mice having defects in Fas/FasL genes develop diseases resembling human systemic lupus erythematosus (SLE). It has been reported that Fas expression of circulating lymphocytes is enhanced in patients with SLE. Nonetheless, apoptosis of SLE lymphocytes is not accelerated. Expression of FasL was detected marginally in unstimulated lymphocytes in normal individuals. In contrast, freshly isolated SLE lymphocytes showed enhanced expression of FasL without in vitro stimulation. We also found the presence of circulating anti-FasL autoantibody in patients with SLE. These results suggest that aberrant FasL expression of lymphocytes and anti-FasL autoantibody are, at least in part, involved in the immune-abnormalities and pathogenesis of the disease.

Animals↗
PubMed1996

[Research for basic and clinical aspects of Behcet's disease--recent advance and future--].

To elucidate the role played by HLA-B51 in the neutrophil hyperfunction of Behcet's disease, we determined the superoxide production by purified peripheral blood neutrophils from Behcet's disease patients, from HLA-B51 positive healthy individuals, and from HLA-B51 transgenic mice. As a result, a significant correlation between the neutrophil hyperfunction and the possession of HLA-B51 phenotype, regardless of the presence of the disease, was observed in humans. FMLP-stimulated neutrophils (without in vitro priming) from HLA-B51 transgenic mice, but not those from HLA-B35 transgenic mice or from nontransgenic mice, produced substantial amounts of superoxide. The HLA-B51 molecule itself may thus be responsible, at least in part, for neutrophil hyperfunction in Behcet's disease. CD4+ alphabeta T cells in this disease proliferated vigorously in response to specific peptide derived from human heat shock protein (HSP)-60; however, CD4+ alphabeta T cells from normal subjects or patients with rheumatoid arthritis did not. This peptide has the amino acid sequence 336-351 of human HSP60, which is similar, but not identical to specific peptide of mycobacterial HSP-65. To clarify whether the peptide stimulates patients' T cells as a polyclonal activator, a specific antigen or superantigen-like substance, we have also analyzed TCR usage of responsive T cells by means of TCR Vbeta subfamily-specific mAbs and PCR single strand conformation polymorphism-based technique. We found that T cells with specific TCR Vbeta subfamilies proliferated and increased in number in response to the peptide by an antigen-specific fashion. The result of recurrent exposure to the HSP may break the tolerance to self HSP, and provoke T cell responses to self and microbial HSP. Such T cells may produce Th1-like proinflammatory cytokines and lead to tissue injury possibly via delayed-type hypersensitivity reaction, macrophage activation, and activation and/or recruitment of neutrophils. Our data shed a new light on the autoimmune nature of Behcet's disease; a novel multistep molecular mimicry mechanism may induce and/or exacerbate Behcet's disease by bacterial antigens that activate T cells previously educated by self-peptide(s) of HSP. This would lead to positive selection of autoreactive T cells in this disease.

Animals↗
PubMed1996

Hormones and lupus: defective dehydroepiandrosterone activity induces impaired interleukin-2 activity of T lymphocytes in patients with systemic lupus erythematosus.

There is strong evidence to implicate the involvement of sex steroid hormones in the pathogenesis of systemic lupus erythematosus (SLE). However, the precise role of an imbalance of circulating sex hormones in the pathogenesis of the disease remains to be fully elucidated. Recent studies of our own as well as others have shown that dehydroepiandrosterone (DHEA), an intermediate compound in testosterone synthesis, significantly up-regulates IL-2 production of normal T cells and that administration of exogenous DHEA or IL-2 via a vaccinia construct to mice with murine lupus dramatically reverses their clinical autoimmune diseases. Thus, it is possible that in patients with SLE, the reported deficiency of IL-2 production is associated with defective DHEA activity. Indeed, we found that nearly all of the patients examined have very low levels of serum DHEA. The decreased DHEA levels are not simply a reflection of long term corticosteroid treatment, since serum samples drawn at the onset of disease, prior to any corticosteroid treatment also contained low levels of DHEA. In addition, supplementation with DHEA of the in vitro cultures of T cells restored impaired IL-2 production in patients with SLE. Thus, it would be suggested that defects of IL-2 synthesis in patients with SLE are at least in part due to the low DHEA activity in the serum, and that supplementation of DHEA could improve clinical manifestations in patients with SLE.

Animals↗
PubMed1995

Excessive function of peripheral blood neutrophils from patients with Behçet's disease and from HLA-B51 transgenic mice.

OBJECTIVE: To elucidate the role played by HLA-B51 in the neutrophil hyperfunction of Behçet's disease, we determined the superoxide production by purified peripheral blood neutrophils from Behçet's disease patients, from HLA-B51 positive healthy individuals, and from HLA-B51 transgenic mice. METHODS: Neutrophil function was evaluated by flow cytometric analysis, detecting the conversion of 2',7'-dichlorofluorescin diacetate into dichloroflurescein, induced by superoxide in the neutrophils. RESULTS: A significant correlation between the neutrophil hyperfunction and the possession of HLA-B51 phenotype, regardless of the presence of the disease, was observed in humans. FMLP-stimulated neutrophils (without in vitro priming) from HLA-B51 transgenic mice, but not those from HLA-B35 transgenic mice or from nontransgenic mice, produced substantial amounts of superoxide. CONCLUSION: The HLA-B51 molecule itself may be responsible, at least in part, for neutrophil hyperfunction in Behçet's disease.

Animals↗