Biomedical subjects

T Kishimoto

Publications and source records attributed to T Kishimoto.

At least 109 records · Page 6Linked to original sources

PubMed2000

Asymmetry in the nonmesonic weak decay of polarized (5)(Lambda)He hypernuclei

We have measured the asymmetric emission of protons from the nonmesonic decay of polarized (5)(Lambda)He produced by the (pi(+), K+) reaction. (5)(Lambda)He is an s-shell hypernucleus and its polarization is due to the Lambda. One expects to obtain direct information on the elementary weak Lambda-->p-->np process. The asymmetry parameter has been determined to be 0.24+/-0.22. The implication of the result is discussed.

Journal Article↗

PubMed2000

IL-6 is required for the development of Th1 cell-mediated murine colitis.

Proinflammatory cytokines have been demonstrated to play a crucial role in the pathogenesis of Crohn's disease. Among those cytokines, strong expression of IL-6 has been repeatedly demonstrated. To examine the role for IL-6 in the pathogenesis of Crohn's disease, we introduced anti-IL-6R mAb to a murine model of colitis. Colitis was induced in C.B-17-scid mice transferred with CD45RBhigh CD4+ T cells from BALB/c mice. Anti-IL-6R mAb or rat IgG was administered weekly after T cell transfer. ICAM-1 and VCAM-1 expression were analyzed by immunohistochemistry. Colonic cytokine expression was determined by RT-PCR. Mice treated with mAb showed normal growth, whereas controls lost weight. The average colitis score was 0.64 for mAb-treated mice and 1.80 for controls. T cell expansion in treated mice was less remarkable than in the controls. Colonic ICAM-1 and VCAM-1 expression were markedly suppressed by mAb. IFN-gamma, TNF-alpha, and IL-1beta mRNA were reduced by the treatment. The results presented here show a crucial role for IL-6 in the pathogenesis of murine colitis and suggest a therapeutic potential of anti-IL-6R mAb for treatment of human Crohn's disease.

Animals↗

PubMed2000

Signal transducer and activator of transcription 3 is required for glycoprotein 130-mediated induction of vascular endothelial growth factor in cardiac myocytes.

Activation of glycoprotein (gp) 130 transduces hypertrophic and cytoprotective signals in cardiac myocytes. In the present study, we have demonstrated that signals through gp130 increase the expression of vascular endothelial growth factor (VEGF) in cardiac myocytes via the signal transducer and activator of transcription (STAT) 3 pathway. After activation of gp130 with leukemia inhibitory factor (LIF), expression of VEGF mRNA rapidly increased with a peak at 3 h in cultured cardiac myocytes. Cardiotrophin-1 also enhanced VEGF mRNA expression in a dose-dependent manner. VEGF protein production and secretion to the medium were also enhanced by LIF and cardiotrophin-1 but not by interleukin-6. Adenovirus transfer of the dominant-negative form of STAT3 to cultured cardiac myocytes inhibited induction of VEGF expression induced by LIF, but neither PD98059 nor wortmannin was affected. In murine hearts, intravenous administration of LIF augmented expression of VEGF mRNA; however, the hearts of transgenic mice overexpressing dominant-negative STAT3 showed reduced expression of VEGF mRNA that was not induced after LIF stimulation. These data provide the first evidence that a STAT family protein functions as a regulator of angiogenic growth factors and suggest that gp130/STAT signaling in cardiac myocytes can control vessel growth during cardiac remodeling.

Animals↗

PubMed2000

Cbfa1 is a positive regulatory factor in chondrocyte maturation.

Cbfa1 is a transcription factor that belongs to the runt domain gene family. Cbfa1-deficient mice showed a complete lack of bone formation due to the maturational arrest of osteoblasts, demonstrating that Cbfa1 is an essential factor for osteoblast differentiation. Further, chondrocyte maturation was severely disturbed in Cbfa1-deficient mice. In this study, we examined the possibility that Cbfa1 is also involved in the regulation of chondrocyte differentiation. mRNAs for both Cbfa1 isotypes, type I Cbfa1 (Pebp2alphaA/Cbfa1) and type II Cbfa1 (Osf2/Cbfa1 or til-1), which are different in N-terminal domain, were expressed in terminal hypertrophic chondrocytes as well as osteoblasts. In addition, mRNA for type I Cbfa1 was expressed in other hypertrophic chondrocytes and prehypertrophic chondropcytes. In a chondrogenic cell line, ATDC5, the expression of type I Cbfa1 was elevated prior to differentiation to the hypertrophic phenotype, which is characterized by type X collagen expression. Treatment with antisense oligonucleotides for type I Cbfa1 severely reduced type X collagen expression in ATDC5 cells. Retrovirally forced expression of either type I or type II Cbfa1 in chick immature chondrocytes induced type X collagen and MMP13 expression, alkaline phosphatase activity, and extensive cartilage-matrix mineralization. These results indicate that Cbfa1 is an important regulatory factor in chondrocyte maturation.

Animals↗

PubMed2000

The suppression of small GTPase rho signal transduction pathway inhibits angiogenesis in vitro and in vivo.

Angiogenesis consists of multistep pathways such as the degradation of the matrix, proliferation of the endothelial cells, motility of the endothelial cells, formation of the cord structure and network formation of microvessels. The small GTPase Rho participates in cell motility through actin fiber polymerization. The role of the small GTPase Rho signal transduction pathway in regulating angiogenesis, however, is still unknown. In this study, we investigated the role of the small GTPase Rho signal transduction pathway in angiogenesis in vitro and in vivo using the exoenzyme, Clostridium botulinum C3 transferase, which specifically suppresses Rho and a compound, Y-27632, which suppresses p160ROCK (Rho-associated coiled-coil containing protein kinase). In this paper, we showed that the small GTPase Rho-p160ROCK signal transduction pathway played an important role in angiogenesis both in vitro and in vivo. These results suggest that inhibition of the small GTPase Rho signal transduction pathway by the p160ROCK inhibitor could be a possible new strategy for angiogenic diseases.

Amides↗

PubMed2000

Cancer immunotherapy targeting Wilms' tumor gene WT1 product.

The Wilms' tumor gene WT1 is expressed at high levels not only in acute myelocytic and lymphocytic leukemia and in chronic myelocytic leukemia but also in various types of solid tumors including lung cancers. To determine whether the WT1 protein can serve as a target Ag for tumor-specific immunity, three 9-mer WT1 peptides (Db126, Db221, and Db235), which contain H-2Db-binding anchor motifs and have a comparatively higher binding affinity for H-2Db molecules, were tested in mice (C57BL/6, H-2Db) for in vivo induction of CTLs directed against these WT1 peptides. Only one peptide, Db126, with the highest binding affinity for H-2Db molecules induced vigorous CTL responses. The CTLs specifically lysed not only Db126-pulsed target cells dependently upon Db126 concentrations but also WT1-expressing tumor cells in an H-2Db-restricted manner. The sensitizing activity to the Db126-specific CTLs was recovered from the cell extract of WT1-expressing tumor cells targeted by the CTLs in the same retention time as that needed for the synthetic Db126 peptide in RP-HPLC, indicating that the Db126-specific CTLs recognize the Db126 peptide to kill WT1-expressing target cells. Furthermore, mice immunized with the Db126 peptide rejected challenges by WT1-expressing tumor cells and survived for a long time with no signs of autoaggression by the CTLs. Thus, the WT1 protein was identified as a novel tumor Ag. Immunotherapy targeting the WT1 protein should find clinical application for various types of human cancers.

Animals↗

PubMed2000

Peroxisome proliferator-activated receptors are expressed in mouse bone marrow-derived mast cells.

We examined the expression of peroxisome proliferator-activated receptors (PPARs) and the role of PPARs in cytokine production in mouse bone marrow-derived mast cells (mBMMCs). mBMMCs expressed PPARbeta strongly and gamma slightly, but not alpha. Activation of mBMMCs with antigen or calcium ionophore resulted in the increased expression of PPARgamma mRNA specifically. 15-Deoxy-Delta(12, 14)-prostaglandin J(2) (15d-PGJ(2)) and troglitazone, all PPARgamma ligands, attenuated the antigen-induced cytokine production by mBMMCs. Carbaprostacyclin, a PPARbeta ligand, also inhibited cytokine production, whereas PPARalpha ligands did not. These results suggest that PPARbeta and gamma might be included in the negative regulation of mast cell activation.

Animals↗

PubMed2000

Identity between rat htf and human xbp-1 genes: determination of gene structure, target sequence, and transcription promotion function for HTF.

Hepatocarcinogenesis-related transcription factor (HTF) was originally isolated from rats in which the expression was enhanced in hepatocellular carcinomas. Rat HTF (rHTF) is structurally similar to human X-box-binding protein-1 (hXBP-1), and both factors are unique in respective genomes. A previous study showed that hXBP-1 mRNA is detectable ubiquitously but is enriched in the human liver as rHTF. In this study, we demonstrated the analogous exon-intron organization and significant sequence homology for rhtf and hxbp-1 genes. Alignment of amino acid sequences of rHTF and hXBP-1 revealed that all the characteristic motifs in rHTF were conserved in hXBP-1. Moreover, Southern blotting patterns provided with the rHTF and hXBP-1 probes were basically the same. These two genes were thus thought to belong to the same evolutional lineage. We determined the consensus binding sequence (CRCGTCA) for rHTF by CASTing, and it was found to be nearly the same as that for hXBP-1. Transactivation ability of rHTF was also demonstrated. The rhtf gene generates two types of mRNAs (2.0 kb and 2.5 kb), both of which encode identical rHTF protein. These transcripts had distinct transcription initiation sites. The 2.0 kb promoter, that was revealed by the transient luciferase assay, contained GC-box and CAAT-box. Sequences around the transcription initiation site for the 2.0 kb transcript were similar in rhtf and hxbp-1 genes. Our observations suggest that HTF is a rat homolog of hXBP-1.

Animals↗

PubMed2000

Signal transducer and activator of transcription 3 in the heart transduces not only a hypertrophic signal but a protective signal against doxorubicin-induced cardiomyopathy.

The signal transducer and activator of transcription (STAT) 3, a transcriptional factor downstream of several cytokines, is activated by Janus kinase families and plays a pivotal role in cardiac hypertrophy through gp130. To determine the physiological significance of STAT3 in vivo, transgenic mice with cardiac-specific overexpression of the Stat3 gene (STAT3-TG) were generated. STAT3-TG manifested myocardial hypertrophy at 12 wk of age with increased expression of the atrial natriuretic factor (ANF), beta-myosin heavy chain (MHC), and cardiotrophin (CT)-1 genes. The animals were injected i.p. with 15 mg/kg doxorubicin (Dox), an antineoplastic drug with restricted use because of its cardiotoxicity. The survival rates after 10 days were 25% (5/20) for control littermates (WT), but 80% (16/20) for STAT3-TG (P < 0.01). WT showed increased expression of beta-MHC and ANF mRNAs in the hearts 1 day after Dox treatment; this expression peaked at 3 days, suggesting that the WT suffered from congestive heart failure. Although the expression of these mRNAs was elevated in STAT3-TG hearts before Dox treatment, no additional increase was observed after the treatment. Dox administration significantly reduced the expression of the cardiac alpha-actin and Stat3 genes in WT hearts but not in STAT3-TG. These results provide direct evidence that STAT3 transduces not only a hypertrophic signal but also a protective signal against Dox-induced cardiomyopathy by inhibiting reduction of cardiac contractile genes and inducing cardiac protective factors.

Actins↗

PubMed2000

Improvement in Castleman's disease by humanized anti-interleukin-6 receptor antibody therapy.

Castleman's disease, an atypical lymphoproliferative disorder, can be classified into 2 types: hyaline-vascular and plasma cell types according to the histologic features of the affected lymph nodes. The plasma cell type is frequently associated with systemic manifestations and is often refractory to systemic therapy including corticosteroids and chemotherapy, particularly in multicentric form. Dysregulated overproduction of interleukin-6 (IL-6) from affected lymph nodes is thought to be responsible for the systemic manifestations of this disease. Therefore, interference with IL-6 signal transduction may constitute a new therapeutic strategy for this disease. We used humanized anti-IL-6 receptor antibody (rhPM-1) to treat 7 patients with multicentric plasma cell or mixed type Castleman's disease. All patients had systemic manifestations including secondary amyloidosis in 3. With the approval of our institution's ethics committee and the consent of the patients, they were treated with 50 to 100 mg rhPM-1 either once or twice weekly. Immediately after administration of rhPM-1, fever and fatigue disappeared, and anemia as well as serum levels of C-reactive protein (CRP), fibrinogen, and albumin started to improve. After 3 months of treatment, hypergammaglobulinemia and lymphadenopathy were remarkably alleviated, as were renal function abnormalities in patients with amyloidosis. Treatment was well tolerated with only transient leukopenia. Histopathologic examination revealed reduced follicular hyperplasia and vascularity after rhPM-1 treatment. The pathophysiologic significance of IL-6 in Castleman's disease was thus confirmed, and blockade of the IL-6 signal by rhPM-1 is thought to have potential as a new therapy based on the pathophysiologic mechanism of multicentric Castleman's disease. (Blood. 2000;95:56-61)

Adult↗

PubMed2000

The prevalence of pleural plaques and/or pulmonary changes among construction workers in Okayama, Japan.

BACKGROUND: Since asbestos has been widely used in Japanese building materials since 1960s, a large number of Japanese construction workers may be exposed to asbestos occupationally. METHODS: Among 2951 construction workers in Okayama, Japan, the prevalence of asbestos-induced pleural or pulmonary changes was examined by screening chest x-rays; these findings were confirmed by computed tomography (CT) scanning of the chest. RESULTS: Among 2951 construction workers, 168 (5.7%) were found to have significant findings for pleural plaque or pulmonary changes on chest x-ray. Seventy-four had both pleural plaque and asbestosis, 85 pleural plaques alone, and 9 asbestosis alone. In 11 subjects, pleural plaques were suggested by chest x-ray, but neither pleural plaque nor asbestosis was demonstrated by chest CT. Honeycombing as one of the characteristic findings of asbestosis was found in 29 subjects. Others showed subpleural spots or curvilinear shadow, which suggested the early stage of asbestosis. The occupations of these workers were carpenters (64), plasterers (27), and concrete board cutters (14). About 30% of the workers with these findings were aware that they were handling asbestos in activities such as installation of asbestos boards, and/or asbestos spraying. CONCLUSIONS: As the incidence of malignant mesothelioma and primary lung cancer associated with asbestos exposure are high, screening by chest CT is necessary for detecting asbestos-induced pulmonary and/or pleural lesions. Education for protection such as telling about the presence of asbestos in building materials is also necessary.

Asbestosis↗

PubMed2000

Peroxisome proliferator-activated receptors are expressed in human cultured mast cells: a possible role of these receptors in negative regulation of mast cell activation.

We investigated the expression of peroxisome proliferator-activated receptors (PPAR) in human cultured mast cells (HCMC) by using the reverse transcription-polymerase chain reaction. HCMC expressed mRNA of PPARbeta, gamma1, and gamma2 constitutively, whereas PPARalpha was not detected. Though PPARgamma2 was expressed weakly, activation of HCMC with anti-IgE after IgE sensitization or with calcium ionophore plus phorbol ester resulted in increased expression of PPARgamma2 specifically. These stimuli did not influence the expression of PPARalpha and beta. In addition, provocation of HCMC with IgE or with IL-4 increased the mRNA level of PPARgamma2, and a synergistic effect was observed with the combination of IgE plus IL-4. To investigate a possible role of PPAR in mast cells, we examined the effects of PPAR agonists on cytokine production by HCMC. Prostaglandin (PG) D(2), Delta(12)-PGJ(2), 15deoxy-Delta(12, 14)-PGJ(2) (15d-PGJ(2)), and troglitazone, all of which are PPARgamma agonists, attenuated the production of granulocyte-macrophage colony-stimulating factor by anti-IgE-stimulated HCMC. A similar effect was observed with carbaprostacyclin, a PPARbeta agonist, but not with PPARalpha agonists. Anti-IgE-induced expression of cytokine mRNA, such as TNF-alpha, IL-5 and macrophage inflammatory protein-1alpha mRNA, was also reduced by the treatment with these PPARgamma agonists. Though only Delta(12)-PGJ(2) and 15d-PGJ(2) revealed an inhibitory effect on histamine release, leukotriene C(4) release from HCMC was suppressed by all tested PPARgamma agonists. These results indicate that HCMC express PPARbeta and gamma1/2, which might negatively regulate the activation of HCMC.

Antibodies, Anti-Idiotypic↗

PubMed2000

Enhanced expression and DNA binding activity of two CCAAT/enhancer-binding protein isoforms, C/EBPbeta and C/EBPdelta, in rheumatoid synovium.

OBJECTIVE: To investigate the activation and expression of CCAAT/enhancer-binding proteins (C/EBP), especially C/EBPbeta and -delta, in rheumatoid synovium, and their pathogenic implications in rheumatoid arthritis (RA). METHODS: The activation of C/EBPbeta and -delta was assessed in synovial tissues from patients with RA by electrophoretic mobility shift assay (EMSA); DNA binding activity of C/EBPs was evaluated by measuring EMSA band density. The expression and distribution of C/EBPbeta and -delta in synovial tissues were examined by immunohistochemistry analysis. As a control, synovial tissues from patients with osteoarthritis (OA) were studied. RESULTS: Enhanced DNA binding activity of C/EBPbeta and -delta, 2 major members of the C/EBP family, was detected in synovial tissues from RA patients, while synovial tissues from the patients with OA showed only faint or marginal activity (mean +/- SEM arbitrary units [AU] RA 23.3 +/- 11.7 in RA versus 4.5 +/- 1.3 in OA; P < 0.05). Moreover, the binding activities of the C/EBP proteins were correlated with both serum C-reactive protein levels (r = 0.62, P < 0.05) and synovial interleukin-6 messenger RNA levels (r = 0.60, P < 0.05). In immunohistochemistry studies, C/EBPbeta and -delta were detected predominantly in the rheumatoid synovial lining cells (both CD14+ and CD14- cells). CONCLUSION: C/EBPbeta and -delta may contribute to the pathology of rheumatoid synovitis.

Aged↗

PubMed2000

Tumour necrosis factor alpha (TNF-alpha) interferes with Fas-mediated apoptotic cell death on rheumatoid arthritis (RA) synovial cells: a possible mechanism of rheumatoid synovial hyperplasia and a clinical benefit of anti-TNF-alpha therapy for RA.

To investigate the mechanism of rheumatoid synovial hyperplasia (RASH), the influence of tumour necrosis factor alpha (TNF-alpha) on Fas-mediated apoptotic cell death (Fas-ACD) was examined on cultured rheumatoid synovial cells (RASCs). RASCs were obtained from the synovial tissues of eight patients with rheumatoid arthritis (RA) and SCs from eight patients with osteoarthritis (OA) were used as a control. To examine the influence of TNF-alpha on Fas-ACD, SCs were cultured with anti-Fas antibody (CH11) for 16 h in the absence or presence of different doses of recombinant TNF-alpha. ACD was determined by electron microscopic analysis and the percentage of apoptotic cells was calculated by trypan blue staining. In addition, the expression of Fas and Bcl-2 on RASCs was examined by flow cytometry. As a result, RASCs were more susceptible to Fas-ACD in vitro than OASCs. TNF-alpha interfered with Fas-ACD on RASCs in a dose-dependent manner. Moreover, removal of TNF-alpha activity by a neutralizing anti-TNF-alpha antibody (cA2) restored Fas-ACD. Flow cytometric analysis showed no significant changes in either Fas or Bcl-2 expression on RASCs after the culture with TNFalpha. These results suggest the following: (1) Fas-ACD might be diminished in vivo by local excessive TNF-alpha and this might contribute in part to RASH. (2) The inhibition of Fas-ACD on RASCs by TNF-alpha might not be associated with changes in the expression of Fas or Bcl-2. (3) In addition, considering a magnetic resonance imaging (MRI) finding of marked reduction in the RASH after cA2 treatment, blockade of TNF-alpha activity could restore Fas-ACD in RA synovium, implicating a clinical benefit of anti-TNF-alpha therapy for RA.

Antibodies, Monoclonal↗

PubMed2000

gp130-Dependent signalling pathway is not enhanced in gp130 transgenic heart after LIF stimulation.

Activation of gp130 transduces a hypertrophic signal in the heart, but it is not clear whether signalling through gp130 is enhanced when gp130 is overexpressed in vivo. We generated gp130 transgenic mice (TG) and examined the activation of signalling pathways downstream of gp130 in the hearts. The tyrosine phosphorylation of gp130 was enhanced, the phosphorylation of STAT3 and ERK (extracellular signal regulated kinase) 1/2 was increased and induction of the beta-myosin heavy chain (MHC) gene was observed in TG hearts without significant phenotypic changes. Intravenous administration of leukaemia inhibitory factor (LIF) induced tyrosine phosphorylation of STAT3 and ERK 1/2 and expression of c-fos and beta-MHC mRNAs in wild-type littermates' (WT) hearts. However, enhancement of STAT3 and ERK 1/2 phosphorylation or augmented mRNA expressions was not observed in TG hearts after LIF stimulation. Next, STAT-induced STAT inhibitor (SSI) mRNA expression was examined. The expression of SSI-1, SSI-2, and SSI-3 mRNAs was significantly augmented in TG hearts after LIF stimulation. These results indicate that overexpressed gp130 does not always enhance downstream signals in the hearts and suggest that the SSI family plays a role in the regulation of the gp130-dependent signalling pathway in the hearts.

Age Factors↗

PubMed2000

Isolation and characterization of the murine cardiotrophin-1 gene: expression and norepinephrine-induced transcriptional activation.

Cardiotrophin-1 (CT-1) is a novel cytokine capable of inducing hypertrophy in cardiac myocytes and belongs to the interleukin-6 family that exert their biological effects through gp130. To clarify the involvement and pathophysiological role of CT-1 in myocardial diseases, it is important to characterize the regulation of CT-1 gene expression. In this study, we isolated and characterized the mouse CT-1 gene and studied the expression of CT-1 mRNA under norepinephrine (NE) stimulation. The mouse CT-1 gene constitutes 5.4 kilobases (kb) in length and consists of three exons and two introns. When nucleotide sequences of the coding regions of exons were compared with those of human, exon 1, 2 and 3 share 96%, 84% and 81% homology, respectively. The 2.2 kb of 5; flanking lesion of the mouse CT-1 gene contains a variety of transcription factor binding motif (e.g. CREB, MyoD, NF-IL6, Nkx2.5, GATA). Fluorescent in situ hybridization (FISH) analysis demonstrated that the mouse CT-1 gene was located on chromosome 7F3. The expression of CT-1 mRNA in cardiac myocytes was markedly augmented by NE stimulation, both in vivo and in vitro. Promoter analysis using deletion constructs of the CT-1 gene indicated that the NE responsive element located between -2174/-1540 and this region contained the cAMP responsive element (CRE). Electrophoretic gel mobility shift assays showed enhanced binding activity to the CRE motif in the nuclear extracts from NE-stimulated cardiac myocytes. These studies indicate that CT-1 is abundantly expressed in the heart and that the CRE is a possible cis -acting element of the CT-1 gene under NE-stimulation. These data suggest that the CT-1 gene expression is regulated, at least partially, by transcriptional machinery.

Adrenergic alpha-Agonists↗

PubMed2000

Ileal perforation due to a Richter hernia at the drain insertion site following an operation for idiopathic rectal perforation: report of a case.

A case of a Richter hernia at the insertion site of the drainage tube following open abdominal surgery is reported. A 54-year-old man underwent an emergency operation for an idiopathic rectal perforation. A partial resection of the rectum and drainage using four 10-mm (outer diameter) drainage tubes with round cross sections was performed. Despite an uneventful early postoperative course, an emergency reoperation was required for peritonitis due to a bowel perforation 14 days after removing the drain inserted into the rectosacral space. A laparotomy revealed an incarcerated Richter hernia with ileal perforation through the 10-mm drainage site. The postoperative course after a partial resection of the ileum and drainage with Penrose drains was uneventful. This is the first report of a Richter hernia through the insertion site of a drainage tube in abdominal surgery. The possible occurrence of a Richter hernia in cases with postoperative drainage using large-size round drainage tubes should thus be considered in such patients.

Drainage↗

PubMed2000

Human cytotoxic T-lymphocyte responses specific for peptides of the wild-type Wilms' tumor gene (WT1 ) product.

The product of the Wilms' tumor gene WT1 is a transcription factor overexpressed not only in leukemic blast cells of almost all patients with acute myeloid leukemia, acute lymphoid leukemia, and chronic myeloid leukemia, but also in various types of solid tumor cells. Thus, it is suggested that the WT1 gene plays an important role in both leukemogenesis and tumorigenesis. Here we tested the potential of WT1 to serve as a target for immunotherapy against leukemia and solid tumors. Four 9-mer WT1 peptides that contain HLA-A2.1-binding anchor motifs were synthesized. Two of them, Db126 and WH187, were determined to bind to HLA-A2.1 molecules in a binding assay using transporter associated with antigen processing-deficient T2 cells. Peripheral blood mononuclear cells from an HLA-A2.1-positive healthy donor were repeatedly sensitized in vitro with T2 cells pulsed with each of these two WT1 peptides, and CD8(+) cytotoxic T lymphocytes (CTLs) that specifically lyse WT1 peptide-pulsed T2 cells in an HLA-A2.1-restricted fashion were induced. The CTLs also exerted specific lysis against WT1-expressing, HLA-A2.1-positive leukemia cells, but not against WT1-expressing, HLA-A2.1-negative leukemia cells, or WT1-nonexpressing, HLA-A2. 1-positive B-lymphoblastoid cells. These data provide the first evidence of human CTL responses specific for the WT1 peptides, and provide a rationale for developing WT1 peptide-based adoptive T-cell therapy and vaccination against leukemia and solid tumors.

CD3 Complex↗