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K Katamura

Publications and source records attributed to K Katamura.

46 records · Page 3Linked to original sources
PubMed1990

Effect of phospholipase A2 inhibitors on mouse T lymphocytes. II. Phospholipase A2 inhibitors induce T cell hybridomas and a T cell clone for the formation of glycosylation-inhibiting factor.

The mouse T cell hybridoma 12H5 cells constitutively form glycosylation-enhancing factor (GEF) and produce both IgE-potentiating factor and ovalbumin (OVA)-binding GEF upon antigenic stimulation with OVA-pulsed macrophages. Culture of the 12H5 cells either with nonspecific glycosylation inhibiting factor (GIF) or with a phospholipase A2 (PLA2) inhibitor, ONO-RS-082, stopped the formation of GEF and induced the same cells to form GIF. Induction of the GIF formation by a PLA2 inhibitor was observed even when the 12H5 cells had been treated with mitomycin C, indicating that the switching from the GEF formation to the GIF formation was not due to selective proliferation of a GIF-producing subclone. The OVA-binding GIF produced by the PLA2-inhibitor-treated, antigen-stimulated 12H5 cells binds to homologous antigen (ovalbumin), and shares both antigenic determinant recognized by the monoclonal antibody 14-30 and the lipomodulin-determinant with antigen-specific suppressor inducer factor (TsiF). The present experiments also showed that a typical helper T cell clone, D10, G4.1 cells, constitutively formed GEF and that preculture of the T cell clone with IL-2 and the PLA2 inhibitor switched the cells from the formation of GEF to the formation of GIF. Upon stimulation with antigen-pulsed macrophages, the inhibitor-treated D10.G4.1 cells formed GIF having affinity for conalbumin. The results indicated that the same T cells have the capacity to form either GIF or GEF under different conditions, and suggested that the GIF-producing suppressor T cells may be a phenotype of a subset of helper T cells. Switching of the same cells from the GEF formation to the GIF formation by the PLA2 inhibitor and the ability of the inhibitor to enhance GIF formation suggested that PLA2-inhibitory activity or GIF activity of TsiF is involved in the suppressor T cell cascade.

Aminobenzoates↗
PubMed1989

Relationship between T cell receptors and antigen-binding factors. I. Specificity of functional T cell receptors on mouse T cell hybridomas that produce antigen-binding T cell factors.

Upon antigenic stimulation with OVA-pulsed syngeneic macrophages, the mouse T cell hybridoma 231F1 produced glycosylation inhibiting factor (GIF) having affinity for OVA and IgE-suppressive factors, whereas another T cell hybridoma, 12H5, cells produced OVA-binding glycosylation enhancing factor (GEF) and IgE-potentiating factor. The OVA-binding GIF from the 231F1 cells is an Ag-specific Ts cell factor, whereas OVA-binding GEF from the 12H5 cells is an Ag-specific augmenting factor. Both hybridomas express CD3 complex and functional TCR-alpha beta. Cross-linking of TCR-alpha beta or CD3 molecules on the hybridomas by anti-TCR-alpha beta mAb or anti-CD3 mAb and protein A resulted in the formation of the same factors as those obtained by the stimulation of the cells with OVA-pulsed syngeneic macrophages. It was also found that both the 231F1 cells and 12H5 cells formed IgE-binding factors upon incubation with H-2d and H-2b APC, respectively, with a synthetic peptide corresponding to residues 307-317 in the OVA molecules (P307-317). Six other synthetic peptides, including those containing the major immunogenic epitope, i.e., P323-339, failed to stimulate the hybridomas in the presence of APC. Indeed, all of the 10 T cell hybridoma clones, which could produce either OVA-binding GIF or OVA-binding GEF, responded to P307-317 and APC for the formation of IgE-binding factors. In contrast, GIF/GEF derived from six other hybridoma clones, whose TCR recognized P323-339 in the context of a MHC product, failed to bind to OVA-coupled Sepharose. The results indicate the correlation between the fine specificity of TCR and the affinity of GIF/GEF to the nominal Ag. The amino acid sequence of P307-317 suggested that TCR on the cell sources of Ag-binding factors are specific for an external structure of the Ag molecules.

Animals↗
PubMed1989

Relationship between T cell receptors and antigen-binding factors. II. Common antigenic determinants and epitope recognition shared by T cell receptors and antigen-binding factors.

The T cell hybridomas 231F1 and 12H5 constitutively secrete glycosylation-inhibiting factor (GIF) and glycosylation-enhancing factor (GEF), respectively, which lack affinity for OVA-coupled Sepharose. When the 231F1 and 12H5 cells were stimulated by OVA-pulsed syngeneic macrophages, however, GIF and GEF produced by the cells had affinity for OVA. Both the OVA-binding GIF from the 231F1 cells and OVA-binding GEF from the 12H5 cells bound to a mAb against TCR-alpha beta and a mAb against TCR-alpha, suggesting a serologic relationship between TCR and OVA-binding factors. However, the OVA-binding GIF and GEF bound to mAb 14-12 and 14-30, respectively. Because these mAb do not bind TcR alpha beta-chains, it appears that the Ag-binding factors are different from TCR itself. The OVA-binding factors from both 12H5 cells and 231F1 cells do not bind to urea-denatured OVA. The binding of the factors to OVA Sepharose was inhibited by a peptide corresponding to residues 307-317 (P307-317) in the native OVA, but not by the peptide corresponding to residues 323-339 (P323-339). Furthermore, the OVA-binding factors bound to P306-319-coupled Sepharose but not to P323-339-coupled Sepharose, and were recovered by elution of the former Sepharose at acid pH. The binding of OVA to anti-OVA antibodies was not inhibited by either peptide. Inasmuch as the 231F1 cells and 12H5 cells can be stimulated by P307-317 in the context of a MHC product, it appears that the Ag-binding factors and TCR-alpha beta on the cell sources of the factors may recognize the same epitope in the OVA molecules. The results also showed that Ag-binding factors and antibodies recognize distinct epitopes in the Ag molecules.

Animals↗
PubMed1988

Regulation of Fc epsilon receptor expression on a human monoblast cell line U937.

Fc epsilon receptor (Fc epsilon R) expression on several human cell lines (U937, RPMI 8866, HL 60, THP-1, and Molt 4) and its regulation were examined by immunofluorescent analysis using a monoclonal anti-human Fc epsilon R antibody, H107. Phorbol ester (PMA), recombinant gamma interferon (IFN-gamma) and H107 itself enhanced Fc epsilon R expression on a FC epsilon R positive cell line U937, whereas these reagents did not induce FC epsilon R expression on the Fc epsilon R negative cell lines, Molt 4, HL 60 and THP-1. Dexamethasone not only suppressed by 50% the spontaneous Fc epsilon R expression on U937 cells but also completely inhibited the enhancement of their Fc epsilon R expression on U937 cells induced by PMA, IFN-gamma or H107. Dexamethasone caused a little suppression of Fc epsilon R expression by RPMI 8866 cells. The results showed that Fc epsilon R expression on a human monoblast cell line U937 was up- or down-regulated by a variety of physiological or pharmacological agents. These experimental systems provide a good model for the investigation of the regulatory mechanisms of Fc epsilon R expression.

Antibodies, Monoclonal↗
PubMed1987

Regulation of IgE receptor expression on human peripheral blood lymphocytes by lymphocytosis promoting factor (LPF), lectins and dexamethasone.

Using a monoclonal anti-human Fc epsilon R antibody (H107), we found that lymphocytosis promoting factor (LPF), phytohaemagglutinin (PHA-P) and Concanavalin A (Con A) could induce Fc epsilon R, detected by immunofluorescence study, on normal human peripheral blood lymphocytes without IgE. The number of Fc epsilon R bearing lymphocytes was increased by stimulation with 3, 10 and 10 micrograms/ml of LPF, PHA-P and Con A, respectively, from 6.0 +/- 3.0/1000 cells to 26.0 +/- 7.9, 54.0 +/- 6.7 and 24.8 +/- 7.1/1000 cells, respectively. Although the induction of Fc epsilon R occurred neither in the separated T-enriched fraction (TEF) nor the T-depleted fraction (TDF), it recovered when the two fractions were mixed. The cell free supernatants from TEF stimulated with LPF or PHA-P could increase Fc epsilon R(+) cells in TDF, whereas those from TDF failed to increase them in TEF. The results suggest that the induction of Fc epsilon R occurs mainly on B lymphocytes by the soluble factor(s) formed by T cells stimulated with LPF or PHA-P. The induction of Fc epsilon R by stimulants was completely inhibited by 10(-6) M dexamethasone. It was demonstrated that the effects of dexamethasone on lymphocytes were dual: one was on B cells to inhibit responsive increases of Fc epsilon R, and the other was on T cells to suppress the formation of the soluble factor(s) which induced Fc epsilon R on B cells.

Dexamethasone↗
PubMed1986

Regulation of synthesis of N-linked glycoproteins and their lipid intermediates in human T lymphoblastoid cells.

The synthesis of N-linked glycoproteins and their lipid intermediates was investigated in cell-free preparations of human T lymphoblastoid cells during two phases of cell growth. The incorporation of 14C-labeled Man into glycoproteins and dolichol-linked oligosaccharides was greater during the logarithmic growth phase than the stationary phase. The incorporation of 14C-labeled GlcNAc into dolichol derivatives was increased in the logarithmic phase. However, the synthesis of Dol-P-Man was not significantly different. These data suggest that the differences are due, at least partially, to the increased synthesis of Dol-P-P-GlcNAc.

Carbon Radioisotopes↗
PubMed1985

Inhibitor of 2',5'-oligoadenylate synthetase induced in human T lymphoblastoid cell line treated with deoxyadenosine, deoxycoformycin and interferon.

The effect of deoxyadenosine (dAdo) with deoxycoformycin on the induction of 2',5'-oligoadenylate synthetase by interferon was investigated. After semi-purification through poly(I):poly(C) gel, the activity was similar in control and dAdo-treated cells. However, the activity in the crude extract decreased with rising concentrations of dAdo. On the other hand, the level of 2'-phosphodiesterase, which is also induced by interferon and degrades 2',5'-oligoadenylate, showed no significant change after dAdo treatment. Thus, the crude extract was speculated to contain an inhibitor of 2',5'-oligoadenylate synthetase. Further characterization of the inhibitor revealed that inhibition was not due to dATP accumulation in cells.

2',5'-Oligoadenylate Synthetase↗
PubMedDate not supplied

Induction of eosinophilic granules, nonspecific esterase activity and CD14 expression in the human eosinophilic leukemia cell line, EOL-1.

We examined the expression of eosinophilic granules, esterase activity and CD14 in a human eosinophilic cell line, EoL-1. Unstimulated EoL-1 cells were weakly positive for nonspecific esterase, but negative for surface CD14, and contained a few eosinophilic granule-positive cells. A combination of G-CSF and TNF-alpha increased the eosinophilic granule-containing cells, but failed to increase esterase activity or CD14 expression. IFN-gamma alone or in combination with TNF-alpha enhanced nonspecific esterase activity but failed to induce CD14 expression or increase eosinophilic granule-containing cells. dbcAMP increased eosinophilic granule-containing cells, nonspecific esterase activity and CD14 expression. Specific esterase activity was not detected in any circumstances. EoL-1 cells fractionated by density gradients or CD14 expression showed nonspecific esterase activity and CD14 expression in both the eosinophilic granule-positive and negative cell populations. Forskolin and butyrate had a synergistic effect on CD14 induction and protein kinase A was suggested to play a role in dbcAMP-induced CD14 expression. A protein kinase C activator, phorbol 12-myristate 13-acetate, did not increase eosinophilic granules, nonspecific esterase activity or CD14 expression in EoL-1 cells. The results show that EoL-1 cells can express nonspecific esterase and CD14, but the expression is not necessarily restricted to cells which have differentiated into the monocyte/macrophage lineage.

Antigens, CD↗