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H Nagatake

Publications and source records attributed to H Nagatake.

6 recordsLinked to original sources
PubMed1997

Interaction of the pre-domain of interleukin-1 with the mature domain.

The two interleukin 1 precursors (preIL-1alpha and beta) with a molecular mass of 33 kDa are proteolytically processed to the mature carboxyl-terminal 17-kDa proteins. In this study we newly developed a monoclonal antibody against the precursor domain of IL-1beta (ED7), of which the binding to preIL-1beta was hindered by a polyclonal antibody against the mature domain of IL-1beta. Immunoprecipitation of limited proteolysed preIL-1beta by ED7 suggested that the epitope for ED7 may not be localized at the junction between preIL-1beta and mature IL-1beta. We therefore examined the possibility that the pre-domain of IL-1beta might interact with the mature domain by using chemical cross-linking. V8 protease yielded a mature 17.5-kDa protein from untreated preIL-1beta, but not chemically cross-linked preIL-1beta. However, cleavage of the cross-link with 2-mercaptoethanol liberated a mature 17.5-kDa protein from preIL-1beta, suggesting that the pre-domains of IL-1beta might interact with the mature domain. Similar phenomena were observed with preIL-1alpha. Such an intermolecular interaction may inhibit or modulate the biological activity of mature IL-1s.

Animals↗
PubMed1995

Granule exocytosis in a cultured human natural killer cell-rich population induced by K562 target cells and by PMA/A23187.

Granule exocytosis in natural killer (NK) cells induced by K562 target cells and by PMA/A23187 was examined by measuring N-benzyloxycarboxy-L-lysine esterase activity. We obtained a cultured human NK cell-rich population containing around 90% of CD16+ cells by culturing peripheral blood mononuclear cells with mitomycin C-treated Daudi cells in the presence of IL-2. Granule exocytosis in the cultured NK cells was induced by K562 cells in a target/effector cell ratio-dependent manner. The granule exocytosis induced by K562 cells was inhibited neither by EGTA nor by TMB-8, an intracellular calcium antagonist, nor by a combination of these two reagents, while the exocytosis induced by PMA/A23187 was inhibited in a dose-dependent manner both by EGTA and by TMB-8. However, the cytotoxic activity of the cultured NK cells was inhibited by EGTA, suggesting that calcium is required not for the induction of granule exocytosis but for other steps including its requirement for the exertion of perforin activity.

Cells, Cultured↗
PubMed1994

Expression and function of multidrug resistance P-glycoprotein in a cultured natural killer cell-rich population revealed by MRK16 monoclonal antibody and AHC-52.

Natural killer (NK) cells have been reported recently to be the highest in expressing multidrug resistance (MDR) P-glycoprotein among normal mature lymphoid cells. Using a cultured NK cell-rich population, we have examined the expression and function of P-glycoprotein, in particular its role in NK cell-mediated cytotoxicity, by employing two MDR-reversing agents (nicardipine and AHC-52, a nicardipine analog almost devoid of calcium channel blocking activity) and monoclonal antibody against P-glycoprotein (MRK-16). The expression of P-glycoprotein was detected by flow cytometry and polymerase chain reaction of reverse transcribed mRNA. P-glycoprotein was functional in terms of rhodamine dye excretion and its susceptibility to the MDR-reversing agents. Since the concentration of nicardipine required for 50% inhibition (IC50) of rhodamine dye excretion (2 microM) was close to that of AHC-52 (5 microM), it was suggested that their inhibitory effects were not due to calcium channel blocking activity, and that ACH-52 is a selective inhibitor for P-glycoprotein. The IC50 of nicardipine for NK cell-mediated cytotoxicity (33 microM) was also close to that of AHC-52 (26 microM), indicating that P-glycoprotein is involved in NK cell-mediated cytotoxicity. In support of this, MRK16 inhibited NK cell-mediated cytotoxicity in a concentration-dependent manner. Both binding of target cells to NK cells and post-binding events were affected by AHC-52, suggesting that P-glycoprotein is involved in several steps in NK cell-mediated cytotoxicity.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1994

Processing of interleukin-1 beta in synovial cells freshly isolated from patients with rheumatoid arthritis.

This study examined interleukin-1 beta (IL-1 beta) production by synovial cells from patients with rheumatoid arthritis (RA). Freshly isolated, plastic-adherent, synovial cells from ten of thirteen patients with RA secreted significant levels of IL-1 bioactivity, and the cells from five patients secreted more IL-1 beta bioactivity than IL-1 alpha bioactivity. Further, there was a relatively good correlation between IL-1 beta bioactivity and IL-1 beta converting enzyme (ICE) activity, suggesting that bioactive IL-1 beta is possibly generated through the action of ICE. Analysis of metabolically-labeled IL-1 by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), however, indicated that, although these cells contained both pre IL-1 alpha and beta intracellularly, they secreted predominantly pre IL-1 beta.

Arthritis, Rheumatoid↗