Biomedical subjects

M Kurimoto

Publications and source records attributed to M Kurimoto.

At least 163 records · Page 9Linked to original sources

PubMed1998

An antisense EGFR oligodeoxynucleotide enveloped in Lipofectin induces growth inhibition in human malignant gliomas in vitro.

Epidermal growth factor receptor (EGFR) plays an important role in the progression of malignancy in gliomas. We studied the growth inhibition of the malignant glioma cell lines using an antisense EGFR oligodeoxynucleotide enveloped with Lipofectin. At a concentration of 5 microM of the antisense EGFR oligodeoxynucleotide enveloped with Lipofectin, the proliferation of three malignant glioma cell lines was significantly inhibited (p < 0.05) compared with that of the cells exposed to 5 microM sense EGFR oligodeoxynucleotide. The activity of the tyrosine kinase and the DNA synthesis was also significantly suppressed (p < 0.05). These findings show that the antisense EGFR oligodeoxynucleotide enveloped with Lipofectin has a possibility to become a useful gene therapy against malignant gliomas.

Brain Neoplasms↗

PubMed1998

Apoptosis and suppression of tumor growth by artepillin C extracted from Brazilian propolis.

Artepillin C was extracted from Brazilian propolis. Artepillin C (3,5-diprenyl-4-hydroxycinnamic acid) has a molecular weight of 300.40 and possesses antibacterial activity. When artepillin C was applied to human and murine malignant tumor cells in vitro and in vivo, artepillin C exhibited a cytotoxic effect and the growth of tumor cells was clearly inhibited. The artepillin C was found to cause significant damage to solid tumor and leukemic cells by the MTT assay, DNA synthesis assay, and morphological observation in vitro. When xenografts of human tumor cells were transplanted into nude mice, the cytotoxic effects of artepillin C were most noticeable in carcinoma and malignant melanoma. Apoptosis, abortive mitosis, and massive necrosis combined were identified by histological observation after intratumor injection of 500 microg of artepillin C three times a week. In addition to suppression of tumor growth, there was an increase in the ratio of CD4/CD8 T cells, and in the total number of helper T cells. These findings indicate that artepillin C activates the immune system, and possesses direct antitumor activity.

Animals↗

PubMed1998

Cloning and expression of a single-chain Fv fragment specific for the human interleukin 18 receptor.

We have recently reported the successful purification and characterization of the human interleukin 18 (IL-18) receptor (R) using a monoclonal antibody (MAb) of the IgM kappa class (117-10C) after immunizing mice with cells of the Hodgkin's disease-derived cell line L428. This antibody is specific for the human IL-18R and inhibits the bioactivity of IL-18. Here we report on the polymerase chain reaction (PCR)-assisted cloning and sequencing of cDNAs encoding the variable regions of the light and heavy chains of 117-10C. We expressed the antibody in the form of a single-chain Fv fragment (scFv) in Chinese Hamster Ovary (CHO) cells and purified it from culture supernatants by chromatography. The purified scFv has an affinity for IL-18R of 5.6 x 10(8) M(-1), whereas 117-10C binds to the receptor with an affinity constant of 3.6 x 10(9) M(-1). Since 117-10C is of the IgM class, it is expected to be in the pentamer form and should theoretically therefore bind IL-18R with 10 times the affinity of the single-chain fragment may explain the difference in the affinity constants for the two molecules. The inhibitory efficiency of 117-10C was found to be 6-fold that of scFv in an interferon gamma (IFN-gamma)-inducing assay on the IL-18-responsive cell line KG-1. In conclusion, we have produced a single-chain fragment of a murine anti-human IL-18R antibody that is as potent at binding IL-18 as the parent antibody, and may be useful in neutralizing the cytokine in human conditions associated with high production of IL-18.

Amino Acid Sequence↗

PubMed1998

Expression of interleukin-18 in murine contact hypersensitivity.

In this study, we made a mouse model for contact hypersensitivity (CH) using oxazolone as a contact allergen and examined the expression of interleukin-18 (IL-18) in the diseased skin sites at both mRNA and protein levels. In the kinetic study by semiquantitative RT-PCR, IL-18 mRNA was constitutively produced in normal murine skin but increased significantly at 12 h and peaked at 24 h in the ear skin of CH mice. A positive correlation was confirmed between the IL-18 mRNA signal and CH, as measured by mouse ear swelling response. Histologically, in situ hybridization showed that the IL-18 mRNA signal was weakly observed in the dermis but not the epidermis of normal skin, whereas the IL-18 mRNA signal was found intensively in the dermis, particularly in inflammatory cell areas. Using IL-18-specific antibody immunostaining, it was further found that IL-18 protein production had a histologic location similar to that of IL-18 mRNA in both normal and CH mice. The present study suggests that IL-18 may be implicated in the pathogenesis of murine CH.

Animals↗

PubMed1998

Direct activation of human CD8+ cytotoxic T lymphocytes by interleukin-18.

Direct activation of human cytotoxic T lymphocytes (CTL) by interleukin (IL)-18 was observed in a system in which CTL effective against autologous tumor cells were generated. Peripheral blood mononuclear cells (PBMC) from tumor-bearing patients, after removal of natural killer (NK) cells, were cultured in a medium containing IL-1, -2, -4, and -6, with or without IL-18, and stimulated with autologous tumor cells. IL-18 increased the activity of the CTL and the proportion of autologous CD8+ T cells present after 28 days in the induction culture. When purified CD8+ T cells were cultured in the presence of IL-18 and IL-2 for 7 days, the CTL showed enhanced cytotoxic activity against autologous tumor cells. Moreover, a purified CD8+ T cell population, which did not exhibit any apparent cytotoxic activity against autologous tumor cells, displayed cytotoxic activity after 7-day incubation with IL-18. These results suggest that IL-18 may be useful to generate autologous CTL in humans and may thereby contribute to adoptive immunotherapy for tumors.

Adenocarcinoma↗

PubMed1998

Lactobacilli and streptococci induce interleukin-12 (IL-12), IL-18, and gamma interferon production in human peripheral blood mononuclear cells.

Human peripheral blood mononuclear cells (PBMC) were stimulated with three nonpathogenic Lactobacillus strains and with one pathogenic Streptococcus pyogenes strain, and cytokine gene expression and protein production were analyzed. All bacteria strongly induced interleukin-1beta (IL-1beta), IL-6, and tumor necrosis factor alpha mRNA expression and protein production. S. pyogenes was the most potent inducer of secretion of IL-12 and gamma interferon (IFN-gamma), and two of three Lactobacillus strains induced IL-12 and IFN-gamma production. All strains induced IL-18 protein production. IL-10 and IL-4 production was induced weakly and not at all, respectively. Our data show that nonpathogenic lactobacilli and pathogenic streptococci can induce Th1 type cytokines IL-12, IL-18, and IFN-gamma in human PBMC.

Gram-Positive Bacteria↗

PubMed1998

Intracranial germinoma associated with Down's syndrome. Report of 2 cases.

It is well known that Down's syndrome is sometimes associated with leukemia. However, there have been only a few case reports of a relationship between Down's syndrome and brain tumors. We report 2 cases with histological diagnoses of germinoma. The 1st case was a 10-year-old boy with Down's syndrome complaining of seizure and left hemiparesis. Computed tomographic (CT) scan and magnetic resonance imaging (MRI) showed a mass lesion in the right basal ganglia and thalamus. Histological examination indicated two cell pattern germinomas. The 2nd case was a 20-year-old man with Down's syndrome complaining of headache and vomiting. CT scan and MRI showed a pineal region tumor with marked hydrocephalus. Surgical specimens showed typical germinoma. Only 13 cases of brain tumors associated with Down's syndrome have been reported. A higher incidence of germ cell tumors seems to be related to chromosomal abnormalities.

Adult↗

PubMed1998

Pseudo-cerebrospinal fluid rhinorrhea after skull base surgery.

A 41-year-old female underwent complete resection of a left petroclival meningioma via an anterior transpetrosal approach, during which the greater superficial petrosal nerve was divided. On the 14th day after the operation, she first noticed leakage of clear fluid from her right nostril whenever the ambient room temperature rose. This pseudo-cerebrospinal fluid rhinorrhea may have developed because of parasympathetic hypersensitivity due to division of the greater superficial petrosal nerve.

Adult↗

PubMed1998

Correlation of prognosis of breast cancer patients and expression of Ley which acts as a cofactor of tumor procoagulant.

Association between Ley expression and prognosis of breast cancer was investigated using monoclonal antibody (MoAb) FS01, which recognizes Ley as an epitope, inhibits the procoagulant activity of cancer cell-derived coagulating activity 1 (CCA-1). Expression intensity and procoagulant activity of CCA-1, tissue factor and HLA-DR on breast cancer cell lines were also examined. Immunohistochemical staining of Ley was performed on primary lesions of 223 breast cancer patients who received absolute curative operation. Flow cytometric analysis and clot timer was used to detect expression and activity of each procoagulant on cancer cell lines. The Ley expression was 73.5%, and no significant relation was observed between clinicopathological factors and intensity of Ley expression. The group showing strong Ley positivity had a significantly poorer prognosis than the Ley-negative group in 5-year disease-free survival (p=0.019). Multivariate analysis using the Cox's proportional hazards' regression model showed that Ley expression is an independent prognostic factor (p=0.018), following tumor size and lymph node metastasis. Ley expression on cancer cell surface is higher than tissue factor and HLA-DR. FS01 and anti-tissue factor MoAb inhibited the coagulating activity of tissue factor-expressing lines, but no cells were inhibited by staphylococcal enterotoxin A, which is known to inhibit the coagulating activity of HLA-DR. CCA-1 and tissue factor plays a important role in the blood coagulating activity of breast cancer cell lines. Breast cancer patients are thought to have a poor prognosis because Ley expression on the surface of the cancer cell induces blood coagulation via CCA-1.

Aged↗

PubMed1997

Le(y) glycolipid acts as a co-factor for tumor procoagulant activity.

We have generated a monoclonal antibody (MAb), FS01, which inhibits the procoagulant activity (CCA-1) produced by a human squamous cell carcinoma cell line, LK52. Expression of the antigen recognized by FS01 MAb in various cancer cell lines correlated well with the procoagulant activities of the expressing cell lines. Our objective was to characterize the molecule reacting with FS01 MAb and to analyze its involvement in the CCA-1 procoagulant activity. The molecule was identified as a glycolipid and found to be involved in the procoagulant activity because both procoagulant activity and reactivity to FS01 MAb were lost after endoglycoceramidase treatment of CCA-1. Furthermore, FS01 MAb recognized the Lewis Y (Le[y]) antigen. To confirm the involvement of a glycolipid incorporating the Le(y) antigen in the procoagulant activity, we attempted to purify CCA-1 from LK52 culture supernatant. In one of the purification steps, a fraction containing low procoagulant activity (CCA-1p) separated from the Le(y)-positive fraction (CCA-1c). Although CCA-1c alone did not show procoagulant activity, the procoagulant activity of CCA-1p was augmented by CCA-1c and this augmentation was inhibited by FS01 MAb. Furthermore, CCA-1c enhanced the procoagulant activity of 33 cell lines tested as well as CCA-1p. In addition, purified Le(y) glycolipid from canine intestine augmented the procoagulant activity of CCA-1p, and this augmentation also could be inhibited by FS01 MAb. We conclude that Le(y) glycolipid is a co-factor for the procoagulant activity derived from cancer cells.

Animals↗

PubMed1997

A simple and sensitive bioassay for the detection of human interleukin-18/interferon-gamma-inducing factor using human myelomonocytic KG-1 cells.

Interleukin-18 (IL-18)/interferon-gamma-inducing factor (IGIF) is a novel cytokine which plays an important role in Th1 responses. Here we describe a simple, sensitive bioassay for human IL-18 using the human myelomonocytic cell line, KG-1, which produces IFN-gamma in response to human IL-18. IFN-gamma production induced by human IL-18 was completely blocked by an antibody against human IL-18. Human IL-18 could be measured in a concentration range from approximately 100 to 10,000 pg/ml, and intra- and inter-assay coefficient variations were both below 15%. It was possible to measure human IL-18 in human serum, cell lysate or culture supernatant by this bioassay. Thus, the human IL-18 bioassay can be expected to be useful in the investigation of the relationship between human IL-18 and various diseases or in analyzing the mechanisms of human IL-18 secretion from IL-18 producing cells.

Animals↗

PubMed1997

IL-18 protects mice against pulmonary and disseminated infection with Cryptococcus neoformans by inducing IFN-gamma production.

We examined the effects of a newly identified cytokine, IL-18, originally designated as IFN-gamma-inducing factor, in a mouse model of pulmonary and disseminated infection with a highly virulent strain of Cryptococcus neoformans. Administration of murine rIL-18 enhanced elimination of live micro-organisms from the lungs, prevented fungal dissemination to the brain, reduced the level of serum cryptococcal capsular polysaccharide Ags, and increased the survival rate of infected mice. Histologic examination of lung sections of infected and PBS-treated mice showed a poor cellular inflammatory reaction and a large number of multiplying C. neoformans yeast cells in alveolar spaces. In contrast, massive infiltration of inflammatory cells, consisting mainly of mononuclear cells, characterized sections of lungs of infected animals treated with IL-18. Treatment with IL-18 also increased the level of serum IFN-gamma. In addition, the protective effect of IL-18 on cryptococcal infection was abrogated by administration of neutralizing anti-IFN-gamma mAb. Finally, we examined the effect of neutralizing anti-IL-18 Ab on cryptococcal infection to define the physiologic role of this cytokine in host defense using another weakly virulent strain of C. neoformans, which induced the expression of IL-18 mRNA in the infected lungs. Administration of this Ab exacerbated the infection, as shown by the increased lung burden. Our results indicate that IL-18 plays an important role in host defense against infection with C. neoformans.

Animals↗

PubMed1997

Involvement of caspase-1 and caspase-3 in the production and processing of mature human interleukin 18 in monocytic THP.1 cells.

Recently, human interleukin 18 (hIL-18) cDNA was cloned, and the recombinant protein with a tentatively assigned NH2-terminal amino acid sequence was generated. However, natural hIL-18 has not yet been isolated, and its cellular processing is therefore still unclear. To clarify this, we purified natural hIL-18 from the cytosolic extract of monocytic THP.1 cells. Natural hIL-18 exhibited a molecular mass of 18.2 kDa, and the NH2-terminal amino acid was Tyr37. Biological activities of the purified protein were identical to those of recombinant hIL-18 with respect to the enhancement of natural killer cell cytotoxicity and interferon-gamma production by human peripheral blood mononuclear cells. We also found two precursor hIL-18 (prohIL-18)-processing activities in the cytosol of THP.1 cells. These activities were blocked separately by the caspase inhibitors Ac-YVAD-CHO and Ac-DEVD-CHO. Further analyses of the partially purified enzymes revealed that one is caspase-1, which cleaves prohIL-18 at the Asp36-Tyr37 site to generate the mature hIL-18, and the other is caspase-3, which cleaves both precursor and mature hIL-18 at Asp71-Ser72 and Asp76-Asn77 to generate biologically inactive products. These results suggest that the production and processing of natural hIL-18 are regulated by two processing enzymes, caspase-1 and caspase-3, in THP.1 cells.

Amino Acid Sequence↗

PubMed1997

Interleukin 18 induces the sequential activation of natural killer cells and cytotoxic T lymphocytes to protect syngeneic mice from transplantation with Meth A sarcoma.

We have recently reported that interleukin 18 (IL-18) pretreatment induces immunologically mediated antitumor effects in BALB/c mice injected i.p. with syngeneic Meth A sarcoma. In this study, mice were pretreated with IL-18 before Meth A transplantation, and immunocompetency in pretreated or untreated tumor-bearing mice (TBM) 3, 9, and 15 days after transplantation was compared with that of normal mice. On day 3, pretreated TBM mitogen-stimulated spleen cells produced significantly decreased levels of IL-2 and IFN-gamma during 24-h culture. In contrast, IL-10 and granulocyte macrophage colony-stimulating factor productions were significantly enhanced in pretreated TBM cultures, and natural killer (NK) cell activity was also significantly augmented. Splenomegaly was also observed in the pretreated TBM on day 3, and the proliferating cells were identified as asialo GM1+ cells by flow cytometry. Cytotoxic activity of pretreated TBM spleen cells after a 5-day mixed lymphocyte-tumor cell culture did not differ from that of untreated TBM and normal mice on day 3 but was significantly enhanced on days 9 and 15 compared with that observed in normal mice and untreated TBM. Concurrently, the production of IL-2 and of IL-10 recovered and decreased, respectively, and NK activity dropped to normal levels. The effects of IL-18 on cytokine production and NK activity observed on day 3 treated TBM were also reproduced in normal mice. In conclusion, IL-18 seems to enhance the generation of NK activity early after tumor transplantation and simultaneously induces an increase and a decrease in the production of IL-10 and IL-2, respectively. As NK activity subsides to normal levels and IL-10 synthesis decreases, IL-2 synthesis is restored, and cytolytic cell activity is significantly enhanced. These results provide new insight into the immunologically mediated antitumor effects of IL-18.

Animals↗

PubMed1997

Purification and characterization of the human interleukin-18 receptor.

Interleukin (IL)-18 was identified as a molecule that induces IFN-gamma production and enhances NK cell cytotoxicity. In this paper, we report upon the purification and characterization of human IL-18 receptor (hIL-18R). We selected the Hodgkin's disease cell line, L428, as the most strongly hIL-18R-expressing cell line based on the results of binding assays. This binding was inhibited by IL-18 but not by IL-1beta. The dissociation constant (Kd) of 125I-IL-18 binding to L428 cells was about 18.5 nM, with 18,000 binding sites/cell. After immunizing mice with L428 cells and cloning, a single monoclonal antibody (mAb) against hIL-18R was obtained (mAb 117-10C). Sequentially, hIL-18R was purified from 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonic acid (CHAPS)-extracted L428 cells by wheat germ lectin-Sepharose 4B chromatography and mAb 117-10C-Sepharose chromatography. The internal amino acid sequences of hIL-18R all matched those of human IL-1 receptor-related protein (IL-1Rrp), the ligand of which was unknown to date. When expressed in COS-1 cells, the cDNA of IL-1Rrp conferred IL-18 binding properties on the cells and the capacity for signal transduction. From these results, we conclude that a functional IL-18 receptor component is IL-1Rrp.

Amino Acid Sequence↗

PubMed1997

A mechanism underlying synergy between IL-12 and IFN-gamma-inducing factor in enhanced production of IFN-gamma.

IL-12 and IFN-gamma-inducing factor (IGIF) have the capacity to stimulate IFN-gamma production by T cells. Using an IL-12-responsive T cell clone, 2D6, we investigated how these two cytokines collaborate for IFN-gamma production. 2D6 obtained from cultures containing rIL-12 produced IFN-gamma in response to rIGIF. 2D6 from cultures deprived of IL-12 for 24 h produced only marginal levels of IFN-gamma production following stimulation with either rIL-12 or rIGIF alone. However, simultaneous stimulation of these 2D6 cells with both cytokines resulted in strikingly enhanced levels of IFN-gamma production. 2D6 could also be maintained in the presence of rIL-2 instead of rIL-12. 2D6 lines maintained with rIL-12 (2D6(IL-12)) or rIL-2 (2D6(IL-2)) exhibited differential IGIF responsiveness: both lines responded similarly to rIL-2 or rIL-12, whereas the 2D6(IL-12) or 2D6(IL-2) exhibited high or marginal IGIF responsiveness, respectively. The 2D6(IL-12) line expressed IGIF receptor (IGIFR), whereas the 2D6(IL-2) did not. Overnight exposure of the 2D6(IL-12) to rIL-2 reduced IGIFR expression and conversely, exposure of the 2D6(IL-2) to rIL-12 restored IGIFR expression. IGIFR expression by these 2D6 lines correlated with the capacity to produce IFN-gamma in response to rIGIF. Purified naive T cells stimulated with anti-CD3 plus anti-CD28 mAb and subsequently cultured with rIL-12 were also found to express IGIFR and induce enhanced IFN-gamma production following IGIF stimulation. These results indicate that the induction of IGIFR by IL-12 represents one of the mechanisms underlying the synergy between IL-12 and IGIF in IFN-gamma production.

Animals↗

PubMed1997

Decrease in the amount of focal adhesion kinase (p125(FAK)) in interleukin-1beta-stimulated human umbilical vein endothelial cells by binding of human monocytic cell lines.

Monocytes in the blood circulation migrate across endothelial cell monolayers lining the blood vessels and infiltrate into the underlying tissues in inflammation. However, little is known about the mechanisms by which leukocytes migrate across the endothelial barrier after binding and what molecules participate in the process. Addition of the human monocytic cell line THP-1 to interleukin-1beta (IL-1beta)-stimulated human umbilical vein endothelial cells (HUVEC) induced a decrease in the amount of focal adhesion kinase (p125(FAK)) protein, a tyrosine kinase localized at focal contacts and essential for cell attachment to the extracellular matrix, whereas little change was observed in the amount of other molecules associated with cell adhesion such as vascular cell adhesion molecule-1, alpha-catenin, and talin. A maximum decrease in the amount of p125(FAK) was observed 15-30 min after addition of THP-1 cells to HUVEC, after which the level of p125(FAK) gradually recovered. A reduction in the density of actin stress fibers in IL-1beta-activated HUVEC was observed in parallel with the decrease in p125(FAK). The p125(FAK) decrease was partially inhibited by preventing THP-1 binding to HUVEC using a mixture of antibodies to adhesion molecules. We suggest that the decrease in p125(FAK) triggered by binding of monocytes in inflammation facilitates the transendothelial migration of the monocytes by altering the adhesiveness of endothelial cells to the extracellular matrix.

Antibodies, Monoclonal↗

PubMed1997

Interleukin-18 induces activation and association of p56(lck) and MAPK in a murine TH1 clone.

Interleukin-18 (IL-18) was identified as an inducer of interferon-gamma (IFN-gamma) production by stimulated T cells. In this study, we used an ovalbumin-responsive murine Th1 clone (OVA#4), in which DNA synthesis was reportedly enhanced after IL-18 treatment in the presence of a non-mitogenic TCR/CD3 stimulus, to examine signal transduction pathways. In the presence of the stimulus, IL-18 induced the appearance of tyrosine-phosphorylated proteins and herbimycin A inhibited DNA synthesis. It is suggested that protein tyrosine kinase (PTK) mediated signaling is induced by IL-18. Specifically, IL-18 induced phosphorylation of phosphorylates p56(lck) (LCK) and mitogen-activated protein kinase (MAPK). IL-18 alone induced the kinase activities of both LCK and MAPK, and the activities were increased by the TCR/CD3 stimulus. Simultaneously, IL-18 induced the association of LCK with MAPK and this was also increased by the TCR/CD3 stimulus. The activation of the LCK-MAPK pathway correlated with enhanced DNA synthesis in OVA#4 cells. These results suggest that the LCK-MAPK pathway is involved in IL-18 signaling and that IL-18 may play an important role in modification of TCR/CD3-mediated response.

Animals↗