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Noriko Okada

Publications and source records attributed to Noriko Okada.

At least 19 recordsLinked to original sources
PubMed2006

Inhibition of HIV-1 infection by synthetic peptides derived CCR5 fragments.

HIV-1 infection requires interaction of viral envelope protein gp160 with CD4 and a chemokine receptor, CCR5 or CXCR4 as entry coreceptor. We designed HIV-inhibitory peptides targeted to CCR5 using a novel computer program (ANTIS), which searched all possible sense-antisense amino acid pairs between proteins. Seven AHBs were found in CCR5 receptor. All AHB peptides were synthesized and tested for their ability to prevent HIV-1 infection to human T cells. A peptide fragment (LC5) which is a part of the CCR5 receptor corresponding to the loop between the fifth and sixth transmembrane regions (amino acids 222-240) proved to inhibit HIV-1IIIB infection of MT-4 cells. Interaction of these antisense peptides could be involved in sustaining HIV-1 infectivity. LC5 effectively indicated dose-dependent manner, and the suppression was enhanced additively by T20 peptide, which inhibits infection in vitro by disrupting the gp41 conformational changes necessary for membrane fusion. Thus, these results indicate that CCR5-derived AHB peptides could provide a useful tool to define the mechanism(s) of HIV infection, and may provide insight which will contribute to the development of an anti-HIV-1 reagent.

Amino Acid Sequence↗
PubMed2006

Mibefradil-sensitive component involved in the plateau potential in submucosal interstitial cells of the murine proximal colon.

Submucosal interstitial cells of Cajal (ICC(SM)) produce plateau potentials comprised of initial fast and subsequent plateau components. The possible involvement of voltage-dependent Ca(2+) channels in plateau potentials was examined in ICC(SM) of the murine proximal colon. Increases in external K(+) concentration ([K(+)](o)) changed the rise rate of the initial component in a biphasic way, an increase in 10.6 or 15.3mM [K(+)](o) and a decrease in 20.0mM [K(+)](o). The rise rate of plateau potentials was significantly reduced by the application of 3 microM mibefradil or 100 microM Ni(2+) but not by 0.3 microM nifedipine. The inhibitory effect of mibefradil on the rise rate of plateau potentials was concentration-dependent with an IC(50) value of 1.0 microM. In conclusion, the initial phase of plateau potentials is partly due to the activation of T-type Ca(2+) channel in ICC(SM) from the murine proximal colon.

Action Potentials↗
PubMed2006

Diagnostic surface expression of SWAP-70 on HIV-1 infected T cells.

Following immunization with HIV-1 infected cells, a hybridoma cell line termed 9F11 was established from the P3U-1 myeloma line fused with lymphocytes from a trans-chromosome (TC) mouse, that harbors human chromosomes containing immunoglobulin genes. The 9F11 human IgM monoclonal antibody (9F11 Ab) reacts with HIV-1 infected MOLT4 cells but not with uninfected MOLT4 cells, and causes immune cytolysis with homologous human complement at a concentration as low as 0.4 microg/ml. This Ab was used to perform immunoscreening of a cDNA expression library derived from HIV-1 infected cells. All positive cDNA clones contained SWAP-70 cDNA. SWAP-70 RNA and protein expression are much stronger in HIV-1 infected cells. SWAP-70 was also detected on the surface of HIV-1 infected cells by flow cytometric analysis. The monocyte cell line U937 cells expresses SWAP-70 on its cell surface regardless of whether it was infected with HIV-1. Furthermore, among PBMCs surface expression of SWAP-70 was detected on CD21+, CD56+ and CD14+ cells. Although CD3+ cells scarcely express SWAP-70 on their surface, once activated, they become positive. SWAP-70 may therefore serve as a marker for T cell differentiation as well as for HIV-1 infection.

Animals↗
PubMed2005

Contribution of anaphylatoxins to allergic inflammation in human lungs.

The contribution of complement activation to allergic asthma remains controversial. In order to elucidate the role played by the complement split products, anaphylatoxins C3a and C5a, we evaluated their effects on production of cysteinyl-leukotrienes (cysLTs) by human lung fragments following an anaphylactic reaction. The lung tissues obtained from two patients with lung cancer showed C5aR-, C5L2R-, and C3aR-mRNA expression. When the chopped lung fragments passively sensitized with human IgE were incubated with anti-human IgE antibody, a significant amount of cysLTs was generated in comparison with the control (without anti-IgE antibody). The co-addition of human C5a at doses of 0.1 to 10 ng/ml to the anti-IgE antibody potentiated cysLT production. The response was bell-shaped in distribution, significant, and peaked at a C5a concentration of 1 ng/ml. The co-addition of human C3a up to 1,000 ng/ml seemed to increase cysLT production, but not to any significant extent. A novel C5a receptor complementary peptide, acetylated peptide A, dose-dependently inhibited cysLT production by the human lung fragments following the anaphylactic reaction in the presence of 1 ng/ml C5a. However, this peptide did not inhibit cysLT production in the presence of 100 ng/ml C3a. It is suggested that the anaphylatoxin C5a potentiates cysLT production in human lung tissues and contributes to allergic inflammation in disorders such as asthma, thus acetylated peptide A may be useful for suppressing allergic inflammation in the lungs.

Anaphylatoxins↗
PubMed2005

Hepatitis induced by an IgM monoclonal antibody against procarboxypeptidase R.

Procarboxypeptidase R (proCPR), also known as thrombin-activatable fibrinolysis inhibitor (TAFI), is present in plasma and can be activated to carboxypeptidase R (CPR) by trypsin-like enzymes such as thrombin and plasmin. CPR has the carboxypeptidase B-like activity that can inactivate the inflammatory peptides such as C5a by removing the C-terminal arginine and can interfere with fibrinolysis by removing C-terminal lysine residue of fibrin. In the present study, we conducted to produce monoclonal antibodies (mAbs) by using spleen cells from proCPR-deficient mice immunized by partially purified mouse proCPR. The mAbs obtained were IgM isotype and reacted with proCPR and interfered with activation of proCPR to CPR by thrombin-thrombomodulin complex. Some BALB/c mice implanted with the hybridoma died in 7 days, and intravenous injection of the mAb to BALB/c mice induced transient elevation of GOT and GPT in plasma although injection to the deficient mice did not. Furthermore, the histological features showed the focally lesions in liver tissue of BALB/c mice injected with the mAb. Since liver is the major site of proCPR synthesis, IgM mAb to proCPR should have induced local inflammation at the side resulting in induction of hepatitis.

Alanine Transaminase↗
PubMed2005

Human IgM monoclonal antibodies reactive with HIV-1-infected cells generated using a trans-chromosome mouse.

The trans-chromosome (TC) mouse that we used harbors human chromosomes 2, 14 and/or 22, and has undergone knock-out of its endogeneous genes coding for mu-and kappa-chains of immunoglobulin. One of these TC mice was immunized with HIV-1-infected U937 cells, and spleen cells from the immunized animal were fused with the mouse myeloma cell line to generate hybridoma cells. We selected hybridomas that produce human IgM antibodies (Abs) reactive with HIV-1-infected MOLT4 cells but not with uninfected MOLT4 cells. Two hybridoma cell lines were established termed 9F11 and 2G9. Although 0.4 mug/ml of 9F11 was able to induce complement-mediated cytolysis of the infected cells in the presence of fresh human serum, 2G9 could not. There was no difference between the two monoclonal Abs in the base sequences of cDNAs coding for the constant regions of mu-and kappa-chains. Therefore, we speculate that the ability to activate complement on homologous cell membranes might reflect the structural presentation of antigenic molecules, which could facilitate the binding of an IgM Ab to multiple binding sites resulting in escape from restriction by species-specific inhibitors of complement such as DAF (CD55) and CD59. On the other hand, 2G9 induced apoptosis of HIV-1-infected cells, including latently infected OM10.1 cells, although the Ag for 2G9 remains to be identified. Since both of the Abs had reduced reactivity toward HIV-1-infected MOLT4 cells following cultivation in the presence of tunicamycin, the responsible antigens would involve a sugar moiety.

Amino Acid Sequence↗
PubMed2005

Helicobacter pylori eradication decreases the expression of glycosylphosphatidylinositol-anchored complement regulators, decay-accelerating factor and homologous restriction factor 20, in human gastric epithelium.

BACKGROUND: It has previously been reported that there is a strong correlation between the expression of glycosylphosphatidylinositol (GPI)-anchored complement membrane inhibitor in gastric epithelium and the severity of inflammation of gastric mucosa. To investigate the regulation of complement activity in gastric epithelium during Helicobacter pylori (H. pylori)-associated gastritis, the expression of GPI-anchored complement membrane inhibitors, decay-accelerating factor (DAF) and 20-kDa homologous restriction factor 20 (HRF20), and membrane cofactor protein (MCP), which is a transmembrane protein, were evaluated after removal of the H. pylori stimulus. Furthermore, the expression of the complement fragment, C3c, was also investigated. METHODS: Forty-six patients with epigastric symptoms and endoscopically confirmed peptic ulcer or gastritis who had H. pylori infection of the gastric mucosa were enrolled in the present study. Biopsy specimens were obtained from the gastric antrum and corpus 1 month before and after eradication. Helicobacter pylori infection was determined by the rapid urease test, histology, and culture before eradication, and by histology, culture, and urea breath test after eradication. Gastric biopsy specimens obtained before and after eradication were evaluated for infiltration by neutrophils and mononuclear cells. The expression of complement membrane inhibitors, DAF, HRF20, and MCP and that of the main complement fragment, C3c, was immunohistochemically evaluated. RESULTS: One month after the eradication of H. pylori, the infiltration by neutrophils and mononuclear cells in the gastric mucosa decreased significantly (P < 0.0001) as compared with that before eradication. The expression of DAF, HRF20, and C3c on gastric mucosal epithelium also significantly decreased in both the antrum and the corpus (P < 0.05) 1 month after eradication. However, no change was observed in the expression of MCP. CONCLUSIONS: The decrease in the expression of GPI-anchored complement regulator and the complement after removal of a chronic microbial stimulus suggests that the gastric epithelium appears to undergo an aggressive stress of complement during H. pylori infection. Conclusively, DAF and HRF20 may play an important protective role against complement-mediated damage induced by chronic microbial stimuli in such a pathological condition.

Amoxicillin↗
PubMed2004

The CC chemokine receptor 4 as a novel specific molecular target for immunotherapy in adult T-Cell leukemia/lymphoma.

Adult T-cell leukemia/lymphoma (ATLL) is a peripheral T-cell neoplasm with dismal prognosis, and no optimal therapy has been developed. We tested the defucosylated chimeric anti-CC chemokine receptor 4 (CCR4) monoclonal antibody, KM2760, to develop a novel immunotherapy for this refractory tumor. In the presence of peripheral blood mononuclear cells (PBMCs) from healthy adult donors, KM2760 induced CCR4-specific antibody-dependent cellular cytotoxicity (ADCC) against CCR4-positive ATLL cell lines and primary tumor cells obtained from ATLL patients. We next examined the KM2760-induced ADCC against primary ATLL cells in an autologous setting. Antibody-dependent cellular cytotoxicity mediated by autologous effector cells was generally lower than that mediated by allogeneic control effector cells. However, a robust ADCC activity was induced in some cases, which was comparable with that mediated by allogeneic effector cells. It suggests that the ATLL patients' PBMCs retain substantial ADCC-effector function, although the optimal conditions for maximal effect have not yet been determined. In addition, we also found a high expression of FoxP3 mRNA and protein, a hallmark of regulatory T cells, in ATLL cells, indicating the possibility that ATLL cells originated from regulatory T cells. KM2760 reduced FoxP3 mRNA expression in normal PBMCs along with CCR4 mRNA by lysis of CCR4+ T cells in vitro. Our data suggest not only that the CCR4 molecule could be a suitable target for the novel antibody-based therapy for patients with ATLL but also that KM2760 may induce effective tumor immunity by reducing the number of regulatory T cells.

Antibodies, Monoclonal↗
PubMed2004

Inhibition of HIV-1 infection in cells expressing an artificial complementary peptide.

TLMA2993 peptide (N'-TLMALELKGKLLLAGLAPSAFLPLSFPEGL-C') which was designed by a computer program (MIMETIC) inhibited the activity of HIV-1 reverse transcriptase in a cell-free system. Therefore, we constructed a TLMA2993 expression vector containing an artificial cDNA for TLMA2993 to generate the peptide in cells. The cell lysate of transfected U937 cells contained a detectable level of TLMA2993 peptide using competitive ELISA. The transfectants were resistant to HIV-1 infection due to expression of TLMA2993 peptide in the cells. The use of MIMETIC to design an inhibitory peptide to any intracellular target molecule, followed by transfection of the artificial cDNA for the peptide, could afford a new approach for treatment and/or prevention of viral infection.

Cell Line↗
PubMed2004

Absence of procarboxypeptidase R induces complement-mediated lethal inflammation in lipopolysaccharide-primed mice.

Carboxypeptidase R (CPR) is a heat-labile enzyme found in serum in addition to stable carboxypeptidase N. CPR cleaves the C-terminal basic amino acids, arginine and lysine, from inflammatory peptides such as complement C3a and C5a, bradykinin, and enkephalin. This enzyme is generated from procarboxypeptidase R (proCPR), also known as thrombin-activatable fibrinolysis inhibitor, following cleavage by proteolytic enzymes such as thrombin, plasmin, and trypsin. We generated proCPR-deficient mice by knocking out exons 4 and 5 of the proCPR gene, which are regarded as essential for CPR function. At LPS challenge, there was virtually no difference in lethality among proCPR(+/+), proCPR(+/-), and proCPR(-/-) mice. However, challenge with cobra venom factor, which can activate and deplete almost all complement in vivo, induced a lethal effect on proCPR(-/-) mice following LPS sensitization which up-regulates C5a receptor expression. In contrast, proCPR(+/+) and proCPR(+/-) mice were able to tolerate the cobra venom factor challenge with the limited dose (30 U). Although carboxypeptidase N plays a role in inactivation of inflammatory peptides in vivo, CPR may also be important in the regulation of hyperinflammation.

Animals↗
PubMed2004

Inhibition of a complement regulator in vivo enhances antibody therapy in a model of mammary adenocarcinoma.

Membrane-bound complement regulatory proteins provide tumor cells with protection from antibody and complement in vitro. However, complement regulators are widely expressed on normal tissue, and inhibiting the function of complement regulatory proteins on tumor cells in vivo has not been investigated due to the absence of appropriate tumor-targeting strategies. Using a mouse model of rat mammary adenocarcinoma, we demonstrate that tumor-specific targeting of a complement regulator with a blocking antibody has functional consequences with regard to both complement deposition on tumor cells and the efficacy of monoclonal antibody therapy. Rat adenocarcinoma 13762 cells express Crry, a widely expressed rodent regulator of complement activation, and are recognized by C595 MAb, an anti-MUC1 MAb in clinical trials. Anti-rat Crry 5I2 MAb and F(ab)(2) enhanced complement deposition on C595 MAb-sensitized 13762 cells in vitro. In vivo, C595 MAb bound to 13762 tumors, albeit not specifically, but was not therapeutic when administered after tumor challenge. However, the coadministration of 5I2 MAb with C595 MAb resulted in enhanced complement deposition and significantly delayed tumor onset and reduced tumor growth; 5I2 MAb alone also enhanced complement deposition and reduced tumor growth but less effectively than when combined with C595 MAb; 5I2 MAb alone did not directly activate mouse complement, but its inhibitory effect on Crry enhanced complement deposition following complement activation by both the alternative pathway and by natural IgM reactive to 13762 cells present in mouse serum. Our proof of principle study shows that inhibiting the function of a tumor-expressed complement regulatory protein enhances immune-mediated clearance of tumor cells and improves prospects for successful immunotherapy. The results justify further research and development of targeting strategies to inhibit or downregulate complement regulatory proteins on tumor cells.

Adenocarcinoma↗
PubMed2004

Mouse complement receptor-related gene y/p65-neutralized tumor vaccine induces antitumor activity in vivo.

Two mouse tumor cell lines, Meth A (BALB/c mouse-derived fibrosarcoma) and MM46 (C3H/He mouse-derived mammary tumor), were shown to express high levels of complement receptor-related gene y/p65 (Crry/p65), a membrane-bound complement-regulatory protein. Inhibiting the complement-regulatory activity of Crry/p65 with mAb 5D5 induced high levels of C3 deposition on in vivo tumor-derived Meth A and MM46 cells. To determine the effect of Crry/p65 blockade and increased C3 deposition on in vivo tumor growth, Meth A and MM46 cells were treated with 5D5 mAb and injected into BALB/c and C3H/He mice, respectively. Pretreating MM46 cells with 5D5 mAb significantly suppressed their tumorigenicity when injected s.c. Pretreatment with 5D5 mAb had a modest effect on Meth A s.c. tumor growth. Because complement is involved in the induction of an immune response, we investigated the effect of Crry/p65 blockade and increased C3 deposition on the immunogenicity of the tumor cells in a vaccination protocol. Vaccination of mice with irradiated Meth A cells pretreated with 5D5 mAb protected mice from subsequent challenge. In contrast, vaccination with irradiated Meth A cells without pretreatment was not protective. Survival was correlated with a high titer IgM response and specific CTL activity. These data demonstrate that the functional inhibition of Crry/p65 on tumor cells affects tumor growth and immunogenicity, and that the complement deposition resulting from this inhibition can act in concert with antitumor effector mechanisms to elicit potent antitumor immunity in vivo.

Animals↗
PubMed2004

Tumor-specific inhibition of membrane-bound complement regulatory protein Crry with bispecific monoclonal antibodies prevents tumor outgrowth in a rat colorectal cancer lung metastases model.

Membrane-bound complement regulatory proteins (mCRP) inhibit complement-mediated tumor cell eradication in vitro and in vivo. Immunotherapy of cancer with monoclonal antibodies (mAbs) that activate complement might be hampered by expression of mCRP on tumor cells. An important strategy to improve mAb immunotherapy can be blocking or overwhelming mCRP at the tumor cells surface in a tumor-specific manner. In our study, we investigated the feasibility of this approach in vivo using bispecific mAbs (bi-mAbs). This study, performed in a syngeneic lung metastases model of rat (WAG/Rij) colorectal cancer, showed that modulation of mCRP on tumor cells resulted in significantly decreased tumor outgrowth. Opsonization of tumor cells with a bi-mAb directed against a tumor-associated antigen and rat mCRP Crry (MG4(2a)*5I2) almost completely prevented the outgrowth of lung tumors (0-7 tumors/rat; n = 17). Opsonization with mAb-cobra venom factor conjugates significantly reduced the number of lung tumors (23-59 tumors; n = 12) compared with the unconjugated MG4(2a) (175-246 tumors; n = 17; P = 0.008 and 0.014, respectively). The effect of MG4(2a)*5I2 was shown to be caused by increased complement activation due to inhibition of Crry. Moreover, prophylactic treatment with MG4(2a)*5I2 or MG4(2a) showed comparable results (3-24 and 215-472 tumors, P = 0.02; n = 6) as observed with pre-opsonized tumor cells without noticeable side effects, despite binding of MG4(2a)*5I2 to endothelium and leukocytes. These results demonstrate that Crry inhibits complement-mediated tumor cell eradication by immunotherapeutic mAbs and show that tumor-specific inhibition of complement regulatory proteins using bi-mAbs can significantly improve mAb-mediated immunotherapy.

Adenocarcinoma↗
PubMed2004

Inactivation of C5a anaphylatoxin by a peptide that is complementary to a region of C5a.

PL37 (RAARISLGPRCIKAFTE) is an antisense homology box peptide composed of aa 37-53 of C5a-anaphylatoxin and is considered to be the region essential for C5a function. Using a computer program, we designed the complementary peptides ASGAPAPGPAGPLRPMF (Pep-A) and ASTAPARAGLPRLPKFF (Pep-B). Pep-A bound to PL37 and to C5a with very slow dissociation as determined by analysis using surface plasmon resonance, whereas Pep-B failed to bind at all. C5a was inactivated by concentrations of 7 nM or more of Pep-A, and this concentration of Pep-A inhibited induction of intracellular Ca(2+) influx in neutrophils. Patch clamp electrophysiology experiments also showed the effectiveness of Pep-A in C5aR-expressing neuroblastoma cells. Furthermore, Pep-A administration prevented rats from C5a-mediated rapid lethal shock induced by an Ab to a membrane inhibitor of complement after LPS sensitization.

Amino Acid Sequence↗
PubMed2004

HIV-1 Nef protein in the nucleus influences adipogenesis as well as viral transcription through the peroxisome proliferator-activated receptors.

BACKGROUND: Although the HIV-1 Nef protein (27 kDa) localizes primarily in cytoplasm, there is considerable evidence suggesting its occasional localization in the nucleus. Nef is known to play an important role in transcriptional events and viral replication, but the actual target of Nef in the nucleus remains to be identified. OBJECTIVE: To examine the functional roles of Nef in the nucleus and its possible interactions with other unknown factors in the nucleus. METHODS: High-density microarray analysis was used to screen directly the unique functions of Nef on host gene transcription. The nuclear localization of Nef and its effects on the expression of peroxisome proliferator-activated receptors (PPAR) was examined using PPAR promoter/reporter assay and immunoblotting. A long terminal repeat/reporter assay was used to investigated the effects of Nef and PPAR on viral transcription. RESULTS: Nef in the nucleus suppressed PPAR gamma expression and reduced fatty acid levels in human T and macrophage cell lines. Expression of Nef or PPAR suppressed viral replication; the effect of PPAR gamma or retinoid X receptor-alpha on viral replication were reduced by coexpression of Nef in MT(-)4 T cells. CONCLUSION: Nef may be involved in both viral replication and the wasting syndrome associated with AIDS.

Adipose Tissue↗