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Biomedical subjects

I Iwamoto

Publications and source records attributed to I Iwamoto.

At least 109 records · Page 6Linked to original sources

Induction of T cell tolerance by pretreatment with anti-ICAM-1 and anti-lymphocyte function-associated antigen-1 antibodies prevents antigen-induced eosinophil recruitment into the mouse airways.

To determine whether the induction of Th2 cell tolerance down-regulates Ag-induced eosinophil recruitment into the tissue, we studied the effect of the in vivo pretreatment with anti-ICAM-1 mAb, anti-LFA-1 mAb, and a soluble Ag on Ag-induced eosinophil infiltration in the trachea of sensitized mice. The in vivo pretreatment with anti-ICAM-1 mAb, anti-LFA-1 mAb, and a soluble Ag inhibited Ag-induced eosinophil infiltration in the mouse trachea in an Ag-specific manner. The pretreatment with anti-LFA-1 mAb and the Ag also had a weak inhibitory effect on the Ag-induced eosinophil infiltration. In contrast, the pretreatment with Ag alone, the combination of anti-ICAM-1 mAb and anti-LFA-1 mAb alone, or the combination of anti-ICAM-1 mAb and the Ag had no significant effect. In addition, the pretreatment with the two mAb and the Ag and, to a lesser degree, the pretreatment with anti-LFA-1 mAb and the Ag also prevented Ag-specific IgE production in mice. In vitro Ag-induced IL-2, IL-4, and IL-5 production was decreased in spleen cells of the mice pretreated with anti-ICAM-1 mAb, anti-LFA-1 mAb, and the Ag, but not with Ag alone or with the combination of anti-ICAM-1 mAb and anti-LFA-1 mAb alone, indicating the induction of both Th1 and Th2 cell tolerance in vivo. These results indicate that the induction of Th2 cell tolerance prevents Ag-induced eosinophil recruitment into the tissue and IgE Ab production and that ICAM-1/LFA-1 interaction is involved as a costimulatory signal in inducing T cell tolerance to a soluble Ag.

Animals↗

IFN-alpha inhibits antigen-induced eosinophil and CD4+ T cell recruitment into tissue.

In a murine model of airway late phase reaction, we have previously shown that Ag-induced eosinophil recruitment into the tissue of sensitized mice is mediated by CD4+ T cells and IL-5. To determine whether IFN-alpha regulates Ag-induced eosinophil recruitment into tissue, we studied the effects of rIFN-alpha, endogenous IFN-alpha production induced by poly I.C, and anti-IFN-alpha mAb on the eosinophil infiltration of the trachea induced by Ag inhalation in mice. The i.p. administration of rIFN-alpha prevented Ag-induced eosinophil infiltration in the trachea of sensitized mice. In addition, the inhibitory effect of rIFN-alpha on Ag-induced eosinophil infiltration was not recovered by pretreatment with anti-IFN-gamma mAb. The administration of rIFN-alpha also inhibited Ag-induced CD4+ T cell infiltration in the trachea. However, the administration of rIFN-alpha did not significantly affect blood eosinophil counts nor the number of blood and splenic CD4+ T cells. On the other hand, pretreatment with anti-murine IFN-alpha mAb enhanced Ag-induced eosinophil and CD4+ T cell infiltration in the trachea. Finally, endogenous IFN-alpha/beta production induced by poly I.C also inhibited Ag-induced eosinophil infiltration in the trachea and this inhibition of the eosinophil infiltration was abrogated by pretreatment with anti-IFN-alpha/beta mAb. These results indicate that IFN-alpha suppresses Ag-induced eosinophil and CD4+ T cell recruitment into tissue.

Aerosols↗

Role of vascular cell adhesion molecule 1/very late activation antigen 4 and intercellular adhesion molecule 1/lymphocyte function-associated antigen 1 interactions in antigen-induced eosinophil and T cell recruitment into the tissue.

To determine the role of vascular cell adhesion molecule 1 (VCAM-1)/very late activation antigen 4 (VLA-4) and intercellular adhesion molecule 1 (ICAM-1)/lymphocyte function-associated antigen 1 (LFA-1) interactions in causing antigen-induced eosinophil and T cell recruitment into the tissue, we studied the effect of the in vivo blocking of VCAM-1, ICAM-1, VLA-4, and LFA-1 by pretreatment with monoclonal antibodies (mAb) to these four adhesion molecules on the eosinophil and T cell infiltration of the trachea induced by antigen inhalation in mice. The in vivo blocking of VCAM-1 and VLA-4, but not of ICAM-1 and LFA-1, prevented antigen-induced eosinophil infiltration into the mouse trachea. On the contrary, the in vivo blocking of VCAM-1 and VLA-4, but not of ICAM-1 and LFA-1, increased blood eosinophil counts after antigen challenge, but did not affect blood eosinophil counts without antigen challenge in sensitized mice. Furthermore, the expression of VCAM-1 but not ICAM-1 was strongly induced on the endothelium of the trachea after antigen challenge. In addition, pretreatment with anti-IL-4 mAb decreased the antigen-induced VCAM-1 expression only by 27% and had no significant effect on antigen-induced eosinophil infiltration into the trachea. The in vivo blocking of VCAM-1 and VLA-4 inhibited antigen-induced CD4+ and CD8+ T cell infiltration into the trachea more potently than that of ICAM-1 and LFA-1. In contrast, regardless of antigen challenge, the in vivo blocking of LFA-1, but not of ICAM-1, increased blood lymphocyte counts more than that of VCAM-1 and VLA-4. These results indicate that VCAM-1/VLA-4 interaction plays a predominant role in controlling antigen-induced eosinophil and T cell recruitment into the tissue and that the induction of VCAM-1 expression on the endothelium at the site of allergic inflammation regulates this eosinophil and T cell recruitment.

Administration, Inhalation↗

Expression of sequences homologous to HTLV-I tax gene in the labial salivary glands of Japanese patients with Sjögren's syndrome.

OBJECTIVE: To address the question of whether the human T cell leukemia virus type I (HTLV-I) gene is associated with the etiology of Sjögren's syndrome (SS). METHODS: RNA expression of HTLV-I gag, pol, env, and tax genes in labial salivary glands (LSGs) from SS patients who were seronegative for antibodies to HTLV-I was examined using reverse transcription and polymerase chain reaction techniques. RESULTS: The HTLV-I tax gene, but not the HTLV-I gag, pol, or env genes, was detected in LSG samples from 4 of 14 patients (29%). The nucleotide sequences of the HTLV-I pXIV region in these 4 patients' LSGs showed 100% homology to the HTLV-I pXIV gene from the MT-2 cell line. CONCLUSION: These findings suggest that products encoding sequences homologous to the HTLV-I pXIV gene in SS patients' LSGs might be candidates for self-antigen and/or lead to activation of autoreactive T lymphocytes through trans-acting transcriptional activation.

Base Sequence↗

Prevention of insulitis and diabetes in beta 2-microglobulin-deficient non-obese diabetic mice.

beta 2-Microglobulin (beta 2m)-deficient non-obese diabetic (NOD) mice were established by crossing beta 2m-deficient 129/Sv mice with NOD mice, and used to examine the possible involvement of MHC class I molecules and CD8+ T cells in the development of insulitis and diabetes. In these mice, MHC class I molecules were not expressed, resulting in no generation of CD8+ T cells. None of eight lines of beta 2m-deficient NOD mice (-/-) established developed overt diabetes by 32 weeks, while control littermates (+/+) became diabetic by 22 weeks. histological studies showed no significant lymphocyte infiltration of the islets (insulitis score: 0.03 +/- 0.03) in any of the beta 2m-deficient NOD mice (-/-) compared with littermate NOD mice (+/+) with overt insulitis (1.42 +/- 0.28). These findings support the notion that the expression of MHC class I molecules and/or CD8+ T cells plays an essential role in the infiltration of CD4+ T cells in islets as well as the development of diabetes in NOD mice.

Animals↗

HLA-DR alleles in patients with Sjögren's syndrome over-representing V beta 2 and V beta 13 genes in the labial salivary glands.

To identify genetic factors that play a role in the pathogenesis of patients with SS over-representing V beta 2 and V beta 13 genes in the lips, HLA-DR and -DQ alleles of 10 primary SS patients with predominant expression of V beta 2 and V beta 13 genes in the lips were analysed, using the polymerase chain reaction (PCR) and sequence specific oligonucleotide probes. The CDR3 amino acid sequences of cDNA clones encoding V beta 2 and V beta 13 genes were also determined by PCR. The results showed that the DRB4*0101 allele was significantly increased (80%) and that the frequency of DRB3 allele was decreased (0%) when compared to findings in healthy subjects (35.6 and 26%, respectively). Sequencing analyses demonstrated that 75% of V beta 2 cDNA clones and 87% of V beta 13 cDNA clones had a glutamine residue at position 106, in the CDR13 region. Moreover, the conserved sequences (Y*TLRNEQ) in the CDR3 of V beta 13-positive T cell were detected in two different clones (27%) from the two individual SS patients. These findings suggest that the decreased DRB3 and increased DRB4*0101 alleles may be associated with the antigens recognized by V beta 2- and V beta 13-positive T cells.

Alleles↗

Inhibitory effect of pemirolast, a novel antiallergic drug, on leukotriene C4 and granule protein release from human eosinophils.

To determine whether pemirolast, a new antiallergic drug, inhibits the activation of eosinophils, we investigated the effect of pemirolast on the release of leukotriene C4 (LTC4) and eosinophil cationic protein (ECP) from human eosinophils. Calcium ionophore A23187 caused both LTC4 and ECP release from human eosinophils, whereas PAF and FMLP induced only ECP release from the eosinophils. Pemirolast (10(-6) to 10(-3) M) inhibited A23187-induced LTC4 release from the eosinophils in a dose-dependent fashion with 77% inhibition at 10(-3) M. Pemirolast (10(-5) to 10(-3) M) inhibited A23187-induced ECP release from the eosinophils in a dose-dependent fashion with 42% inhibition at 10(-3) M. Pemirolast (10(-4) and 10(-3) M) also inhibited PAF-induced and FMLP-induced ECP release from the eosinophils. We conclude that pemirolast prevents the activation of human eosinophils to inhibit LTC4 and ECP release. These results suggest that pemirolast might be useful in controlling allergic diseases by inhibiting eosinophil activation.

Asthma↗

T cell receptor V alpha repertoire of infiltrating T cells in labial salivary glands from patients with Sjögren's syndrome.

OBJECTIVE: To analyze the T cell receptor (TCR) V alpha repertoire of infiltrating T cells in labial salivary glands of patients with Sjögren's syndrome (SS). METHODS: TCR V alpha genes of infiltrating T cells in lips from 2 patients with SS were examined, using the double step inverse polymerase chain reaction. Four and 7 clones encoding the VJC alpha region were established and sequenced, respectively. RESULTS: All 4 clones used the V alpha 17.1 gene in one patient, while 3 (42.8%) of 7 clones from the other patient used the V alpha 2 family gene (V alpha 2.1, V alpha 2.2, V alpha 2.4), and the other 3 clones used the V alpha 11.1 family gene. A comparison using labial salivary glands and peripheral blood showed that the predominant expression of V alpha 2, V alpha 11.1, and V alpha 17.1 gene segments is specific in the salivary glands. CONCLUSION: The TCR V alpha repertoire of infiltrating T cells from the lips of 2 patients with SS was relatively restricted in individual patients, thereby suggesting the limited heterogeneity of these cells in salivary glands.

Amino Acid Sequence↗

[Thrombotic thrombocytopenic purpura (TTP) observed in a patient with primary antiphospholipid antibody syndrome].

Thrombotic thrombocytopenic purpura (TTP) is a rare syndrome of unknown etiology and has a high mortality rate. TTP is characterized by a pentad of clinical findings, including microangiopathic hemolytic anemia, thrombocytopenia, renal abnormalities, neurologic signs and fever. The pathological feature of TTP consists of disseminated microvascular platelet thrombi. We describe a case of TTP with primary anti-phospholipid syndrome. A 27-year-old woman developed TTP in her second trimester of pregnancy. She presented with classical symptoms of TTP with compatible renal biopsy findings. Although four articles of SLE criteria (1982 ARA) were fulfilled, three of them were considered to be derived from multiple thrombosis except for a positive antinuclear antibody. Positive antiphospholipid antibodies (lupus anticoagulant and anticardiolipin antibody) with SLE-like findings suggested the diagnosis of antiphospholipid antibody syndrome rather than SLE. Although TTP has been described in patients with SLE and they can share common clinical and pathological features, the relationship between these two diseases is controversial. Many theories have been proposed to explain the nature and cause of intravascular platelet aggregation in TTP. But the pathogenesis of TTP is still unclear. This case suggests an important causal relationship between antiphospholipid antibodies and TTP during pregnancy. In TTP patients who also have SLE or SLE-like features, the antiphospholipid antibodies may have a role in the development of multiple microthrombosis.

Adult↗

T-cell receptor V beta repertoire of L3T4+ regulatory T cells in anti-L3T4 antibody-induced tolerant NOD mice.

In ongoing studies, we have found that short-term administration of anti-L3T4 monoclonal antibodies (mAb) prevents the development of overt diabetes in non-obese diabetic (NOD) mice. In the present work, we asked whether L3T4+ T cells or Lyt-2+ T cells can suppress the diabetes in these mice. L3T4+ T cells or Lyt-2+ T cells were sorted using a magnetic cell sorter, then were transferred into cyclophosphamide-induced male NOD mice. We obtained evidence that the L3T4+ but not Lyt-2+ T cells did inhibit the diabetes, thereby indicating that the former can regulate diabetes in anti-L3T4 mAb-induced tolerant NOD mice. Further analysis on T-cell receptor (TCR) V beta genes on splenic T cells from anti-L3T4 mAb-treated NOD mice revealed that V beta 4-positive T cells expanded predominantly, while L3T4+ T cells represented heterogeneity of the TCR V beta gene, hence, V beta 4-positive Lyt-2+ T cells generate predominantly. Our findings suggest that both L3T4+ and Lyt-2+ T cells renew and function as regulatory cells, through clonotypic interaction in tolerant NOD mice.

Animals↗

[Inhibitory effect of AS-35. a novel antiallergic drug, on chemical mediator release from human eosinophils].

To determine whether AS-35, a new antiallergic drug, inhibits the activation of eosinophils, we examined the effect of AS-35 on the release of leukotriene C4 (LTC4) and eosinophil peroxidase (EPO) from human eosinophils. Calcium ionophore A23187 caused both LTC4 and EPO release from human eosinophils. AS-35 (1 x 10(-5) M) inhibited A23187-induced LTC4 release from the eosinophils with 56% inhibition. AS-35 (1 x 10(-6) to 1 x 10(-5) M) also inhibited A23187-induced EPO release from the eosinophils in a dose-dependent fashion with 79% inhibition at 1 x 10(-5) M. We concluded that AS-35 prevents the activation of human eosinophils to inhibit LTC4 and EPO release. These results suggest that AS-35 might be useful in controlling allergic diseases by inhibiting eosinophil activation.

Cells, Cultured↗

V gene analysis of anti-cardiolipin antibodies from (NZW x BXSB) F1 mice.

In (NZW x BXSB) F1 (W/B F1) male mice, systemic lupus-like disease, thrombocytopenia and coronary vascular disease with myocardial infarction occur, due to the presence of platelet-associated antibodies, anti-platelet antibodies and anti-cardiolipin antibodies (aCL). We developed monoclonal aCL and analysed the specificity of aCL. In the W/B F1 mice, there are aCL with pathogenic properties, which have an IgG isotype and reveal a cofactor-dependent binding to CL, binding activity to platelets, and lupus anti-coagulant (LA) activity. Here, we analysed the usage of VH and V kappa genes of six aCL, including two pathogenic aCL, from W/B F1 mice, in an attempt to address the question of whether or not aCL with pathogenic properties use restricted Ig V genes. Sequence analysis of VH and V kappa genes of aCL showed that the pathogenic aCL had VHJ558 and V kappa 21 or V kappa 23 genes, whereas the other aCL without pathogenic features used mainly the 7183 VH family and the random V kappa gene group. However, two pathogenic aCL showed a 86.6% homology with the IgV region, each other, indicating that they were not closely related clones. Thus, these findings suggest the possibility that usage of Ig VH genes in pathogenic aCL is not random, but that there may exist a few epitopes of antigen recognized by the pathogenic aCL.

Amino Acid Sequence↗

[Hemophagocytic syndrome observed in a patient with systemic lupus erythematosus].

A 52-year-old woman was admitted to our hospital because of a skin rash, high fever and myalgia. She had been diagnosed ten years ago by a dermatologist as having MCTD (mixed connective tissue disease). At the time of admission a diagnosis of active SLE was made by fulfilling four of the 1982 ARA criteria together with increasing levels of anti-DNA antibody and low levels of complements. Prednisolone (PSL) given orally in an initial dosage of 60 mg/day was effective during the first 6 weeks. Then a high fever, skin rash and pancytopenia appeared without active findings of SLE. Infection caused by bacteria, fungus or virus was suspected, but no infectious agent was present in cultures derived from blood or other sources. Antimicrobic drugs used were not effective at all. The clinical picture was suggestive of a drug allergy, but no causative drug was found. A diagnosis of hemophagocytic syndrome (HPS) was made because of the increased number of unusual hemophagocytic cells in the bone marrow. High levels of serum ferritin and neopterin, which are known to reflect macrophage activation, supported the diagnosis of HPS. HPS is characterized by activated phagocytosis presumably induced by hypersecretion of cytokines. Malignant lymphoma and infection are the two representative diseases which may cause HPS. Recently, an acute lupus HPS was reported in patients with active SLE. Here we reported a case of reactive HPS observed in a patient with SLE who had been receiving high dose PSL. Symptoms and findings of the patient gradually disappeared in several weeks after rapid reduction of the PSL dose.(ABSTRACT TRUNCATED AT 250 WORDS)

Disseminated Intravascular Coagulation↗

Chronic salicylate intoxication and rhabdomyolysis in a patient with scleroderma and Sjögren's syndrome.

A 44-year-old woman with scleroderma and Sjögren's syndrome developed altered consciousness, acute renal failure, and rhabdomyolysis. She had no history of trauma, seizures, alcohol abuse, hyperthermia, or other possible causative factors for rhabdomyolysis. A high serum salicylate level indicated a diagnosis of salicylate intoxication. Medical history after recovery revealed chronic salicylate ingestion for severe headaches. This is possibly the first reported case of rhabdomyolysis caused by chronic salicylate intoxication. Continuous hemodiafiltration early in hospitalization was an effective treatment.

Acute Kidney Injury↗

Leukotriene B4 mediates substance P-induced granulocyte infiltration into mouse skin. Comparison with antigen-induced granulocyte infiltration.

Substance P, a potent proinflammatory peptide present in sensory neurons, causes granulocyte (neutrophil and eosinophil) infiltration into mouse skin by inducing mast cell degranulation. However, the mediator responsible for this granulocyte infiltration has not been determined. In this study, we determined which mediator from cutaneous mast cells mediates substance P-induced granulocyte infiltration in the skin by the use of two mediator antagonists; one for platelet activating factor (PAF) CV-6209 and the other for leukotriene B4 (LTB4) ONO-4057. Subcutaneous injection of substance P (10(-7)-10(-5) M) caused granulocyte infiltration in the skin of BALB/c mice in a time- and concentration-dependent fashion. Pretreatment with the LTB4 antagonist decreased substance P-induced neutrophil and eosinophil infiltration into mouse skin at 6 h to the same extent that an inhibitor of mast cell degranulation, disodium cromoglycate, decreased those responses. However, pretreatment with the PAF antagonist affected neither substance P-induced neutrophil nor eosinophil infiltration at 6 h. A LTC4/D4 antagonist ONO-1078 and a histamine H1 antagonist chlorpheniramine had no effect on the granulocyte infiltration, either. The LTB4 antagonist also decreased substance P-induced neutrophil, but not eosinophil, infiltration into mouse skin at 24 h. In contrast, the PAF antagonist inhibited Ag-induced eosinophil infiltration of mouse skin, whereas the LTB4 antagonist inhibited the Ag-induced neutrophil infiltration. We conclude that LTB4 is a major mast cell-derived chemotactic mediator for initiating substance P-induced neutrophil and eosinophil infiltration into mouse skin. Our results suggest that LTB4 antagonists might be useful in preventing such neurogenic inflammation.

Animals↗

V gene analysis of anticardiolipin antibodies from MRL-lpr/lpr mice.

We analyzed the VH and V kappa genes of 14 hybridomas producing anticardiolipin antibodies (aCL) from MRL-lpr/lpr mice, in an attempt to address the question of whether aCL are generated by Ag-driven stimulation or by polyclonal B cell activation. Five of six aCL from one mouse and both aCL from the other mouse carried 98 to 100% homologous VH and V kappa genes, respectively, thereby indicating that aCL were derived from the oligoclonal B cell precursor in that individual mouse. Of nine clones, six (67%) used the VH gene of the J558 family, and three (43%) of seven clones used the V kappa gene of the V kappa 23 group. Three to five somatic mutations were detected in all VH and V kappa genes of the examined aCL. These results suggest the possibility that usage of VH/V kappa genes in aCL is not random and that aCL consist of somatically mutated Ig genes.

Amino Acid Sequence↗