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T Tadakuma

Publications and source records attributed to T Tadakuma.

89 records · Page 5Linked to original sources
PubMed1979

Primary in vitro immunogenicity of liposomal model membranes in mouse spleen cell cultures.

Neither 2,4-dinitrophenyl-6-N-aminocaproylphosphatidylethanolamine (DNP-Cap-PE) nor fluoresceinthiocarbamylphosphatidylethanolamine (F1-PE) induces hapten-specific plaque-forming cells (PFC) when incubated with suspensions of spleen cells from unimmunized C57BL/6J mice. However, PFC are produced after incorporation of these synthetic lipid antigens into liposomal model membranes. The in vitro response is characterized by the following: a) it is time and dose dependent; b) the frequency of IgM PFC exceeds IgG PFC; c) both nonadherent and adherent cells are required (2-mercaptoethanol can replace the requirement for adherent cells in some experiments); d) depletion of thymus-derived cells by treatment with anti-theta antiserum plus complement does not diminish the response; e) spleen cells from nude BALB/c mice also produce PFC. Thus, the essential features of the in vivo immunogenicity of DNP-Cap-PE and F1-PE sensitized liposomes, which have been previously described, can be replicated in an in vitro cell culture system.

Aminocaproates↗
PubMed1976

Separation of helper T cells from suppressor T cells expressing different Ly components. I. Polyclonal activation: suppressor and helper activities are inherent properties of distinct T-cell subclasses.

Concanavalin A, a nonspecific polyclonal activator of T lymphocytes, activates Lyl and Ly23 subclasses to the same degree. After activation, the Ly23 subclass, but not the Lyl subclass, has the following properties: (a) Suppression of the antibody response to sheep erythrocytes (SRBC) in vitro. (b) Production of a soluble factor that suppresses the anti-SRBC response in vitro. (c) Suppression of the generation of cell-mediated cytotoxicity to H-2 target cells in vitro. Con A-activated cells of the Lyl subclass, but not the Ly23 subclass, express helper function in the anti-SRBC response in vitro. Because the intact Con A-stimulated T-cell population contains both cell types, these cells do not exert detectable helper effects in an anti-SRBC system in vitro, because the helper effect of Lyl cells is masked by the suppressor effect of the Ly23 cells. Each function is revealed by eliminating one or the other population with the relevant Ly antiserum. The resting T-cell population, before activation by Con A, also contains already programmed Lyl and Ly23 cells with similar helper and suppressor potentials, respectively. This is revealed by experiments with Ly subclasses which have been separated from the resting T-cell population and then stimulated by Con A. Thus helper and suppressor functions, as expressed in these systems, are manifestations of separate T-cell-differentiative pathways and do not depend upon stimulation of the cells by antigen.

Animals↗
PubMed1976

Site of action of a soluble immune response suppressor (SIRS) produced by concanavalin A-activated spleen cells.

The cellular site of action of SIRS, a soluble immune response suppressor released by Con A-activated spleen cells which suppresses antibody responses to heterologous erythrocytes by murine spleen cells in vitro, was investigated. Exposure of spleen cells to SIRS for 2 hr at 37 degrees C or 1 hr at 4 degrees C was sufficient to suppress 5-day antibody responses in vitro. Similar exposure of splenic or peritoneal exudate macrophages to SIRS also suppressed antibody responses by untreated splenic lymphoid cells; exposure of splenic lymphoid cells to SIRS was without effect. SIRS did not act via T cells which might have contaminated the macrophage preparations. SIRS-mediated suppression could be partially overcome by an excess of normal peritoneal exudate macrophages, but not by an excess of T or B cells. These data indicate that the target cell of SIRS activity is the macrophage. The results are discussed in the context of macrophage functions that could be affected by SIRS.

Animals↗
PubMed1976

Biological expressions of lymphocyte activation. V. Characterization of a soluble immune response suppressor (SIRS) produced by concanavalin A-activated spleen cells.

Supernatant fluids from murine spleen cell cultures incubated with concanavalin A for 48 hr contain a factor(s), soluble immune response suppressor (SIRS), which suppresses plaque-forming cell responses to sheep erythrocytes by murine spleen cells in vitro. In the present studies, some of the biochemical and biophysical properties of SIRS were investigated. SIRS was non-dialysable; the suppressive activity was stable at 56 degrees C for 30 min, but was destroyed by treatment at 70 degrees C for 30 min, 80 degrees C for 10 min, or at pH 2. The suppressive activity was not absorbed by the stimulating antigen, SRBC, or antisera against murine IgG or mu-chain, suggesting that SIRS does not contain immunoglobulin determinants. Murine spleen and thymus, but not kidney cells, however, absorbed SIRS activity. Enzyme treatments revealed that SIRS was resistant to DNase and RNase, but was destroyed by trypsin and chymotrypsin. In gel filtration with Sephadex G-100, SIRS activity eluted in the fraction corresponding to m.w. in the range between 48,000 and 67,000. With polyacrylamide gel electrophoresis, SIRS activity migrated in the region cathodal to albumin. Isopycnic centrifugation in a cesium chloride gradient suggested that SIRS is a glycoprotein. These supernatant fluids with SIRS activity were also found to contain macrophage migration inhibitory factor (MIF). In the experiments using gel filtration, polyacrylamide gel electrophoresis, and isopycnic centrifugation to fractionate supernatant fluids, SIRS and MIF activity were found in the same fractions, and to date we have been unable to dissociate definitively SIRS activity from MIF activity.

Absorption↗
PubMed1975

In vitro reconstitution of anti-sheep erythrocyte antibody response of T cell-depleted spleen cells by allogeneic T cells or by factors derived from them.

Restoration of the impaired antibody response to sheep erythrocytes (SRBC) in cultures of mouse spleen cells, which were deprived of thymus-derived lymphocytes (T cells) by treatment with anti-mouse brain-associated theta (BA theta) antiserum and complement, was studied by adding a small portion of syngeneic or allogeneic normal spleen cells in vitro. Allogeneic spleen cells had a far greater effect than syngeneic spleen cells on the restoration, as far as the normal spleen cells added were able to recognize the alloantigens on the anti-BA theta serum-treated spleen cells (bone marrow-derived lymphocytes). Treatment of the allogeneic spleen cells with mitomycin C did not affect their activity in the restoration of the impaired antibody response. The possibility that the role of T cells in the antibody response to SRBC may be replaced by a nonspecific mediator derived from T cells reacting with allogeneic cells was proven by the finding that supernatant of the mixed allogeneic spleen cell cultures restored the impaired anti-SRBC antibody response of the T cell-depleted spleen cells. The effect of such culture supernatant on the restoration of the antibody response was greatest when it was added to the T cell-depleted spleen cell cultures one day after cultivation with SRBC, suggesting that the effectiveness may result from triggering of the proliferation and differentiation of antibody-forming cell precursors, which have already reacted with the antigen, to antibody-forming cells.

Animals↗
PubMedDate not supplied

Expression of carbonic anhydrase I or II and correlation to clinical aspects of colorectal cancer.

BACKGROUND/AIMS: This study was undertaken to elucidate the correlation between the expression of carbonic anhydrase I or II and the characteristic features of colorectal cancer. METHODOLOGY: The carbonic anhydrase I or II expressions of 74 colorectal cancer patients were analyzed by Western blotting. The relative intensity of cancer to the paired normal mucosa was calculated, and then compared with the clinicopathological parameters. Furthermore, a multivariate analysis for synchronous distant metastasis was undertaken. RESULTS: The expression of carbonic anhydrase I in colon cancer or carbonic anhydrase II in rectal cancer with Duke's D was found to be significantly lower than that with Duke's B or C, respectively. Similarly, carbonic anhydrase I in colon cancer or carbonic anhydrase II in rectal cancer with moderate-severe budding was found to be significantly lower than that with none-mild budding, respectively. Based on the findings of a logistic regression analysis, carbonic anhydrase I was adopted for colon cancer (P = 0.057) and carbonic anhydrase II for rectal cancer (P = 0.008) regarding synchronous distant metastasis. CONCLUSIONS: The expressions of carbonic anhydrase I and II correlated with biological aggressiveness of colorectal cancer and synchronous distant metastasis, especially carbonic anhydrase I for colon cancer and carbonic anhydrase II for rectal cancer.

Adult↗