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T Takami

Publications and source records attributed to T Takami.

At least 109 records · Page 6Linked to original sources
PubMed1985

Expression of a murine B16 melanoma-associated antigen analyzed by flow cytometry.

Understanding factors regulating expression of tumor antigens is vital to the design of rational immunotherapeutic strategies. A murine monoclonal antibody (MM2-3C6) that recognizes a B16 murine melanoma-associated membrane antigen was used to study antigen expression in relation to cell cycle, clonal heterogeneity, and growth density. Dual-parameter flow cytometric measurements of DNA content and membrane antigen demonstrated that antigen-positive cells were found throughout the cell cycle. However, some antigen-negative cells were observed and were restricted to the G0/G1 phase demonstrating the antigenic heterogeneity of this tumor line. Three sublines of B16, F1, F10, and F1r with variable metastatic potential, and 50 B16 F1 clones all expressed the antigen with a mean antigen density above background of 8.84 +/- 2.52 [( mean cell fluorescence/cell size] X 10(-3] ranging from 3.68 to 16.57. Further studies of three sublines and five clones showed antigen density fluctuated over an 8-day growth period in culture with daily changes of medium. During log growth from Day 1 (1.2 +/- 0.08 X 10(4) cells/cm2) to Day 4 (20.4 +/- 3.01 X 10(4) cells/cm2), antigen density increased from 4.09 +/- 0.29 to 6.86 +/- 0.29. By Day 8 (26.5 +/- 2.86 X 10(4) cells/cm2) when the cells had been confluent for 3 days, antigen density decreased to 2.54 +/- 0.26 which was significantly lower than other days measured (P less than 0.05). It is concluded that tumor cell proliferation and cell density can modulate antigen expression in this system and, therefore, this may be a useful model to study tumor cell escape from immunotherapy.

Animals↗
PubMed1985

An improved procedure of chronic intravenous infusion in unrestrained rats.

A continuous infusion technique for rats is described which is a significant improvement upon existing procedures with regard to the degree of physiological and psychological stress it provokes. The system was assembled with a head attachment, a practical swivel and a special metabolic cage, permitting long-term tube feeding of unrestrained rats.

Animals↗
PubMed1985

A novel human B-lymphocyte antigen shared with lymphoid dendritic cells: characterization by monoclonal antibody.

A novel cell-surface antigen (L25) expressed on human B cells was identified using a B cell-reactive monoclonal antibody (TB1-4D5). This L25 antigen was expressed on most B-lineage cells but not other cell types including thymocytes, T cells, granulocytes and monocytes. Thus, L25 existed on the majority of normal B cells present in the blood and lymphoid tissues, on cultured cell lines derived from normal and malignant B cells, and on neoplastic cells isolated from patients with B cell-derived malignancies. Though L25 was persistently expressed on B cells until 7 days after their activation with pokeweed mitogen (PWM), neither normal nor neoplastic plasma cells expressed L25. Moreover, L25 was present on cultured as well as freshly isolated leukaemic cells with common acute lymphatic leukaemia (CALL) antigen, which have been thought to correspond to the early B-cell ontogeny. Besides pan-B cell reactivity of TB1-4D5 antibody, it apparently cross-reacted with so-called dendritic or interdigitating cells located in the thymic-dependent areas of peripheral lymphoid organs, which have been presumably ascribed to those associated with accessory-cell function. Functional studies showed that anti-L25 (TB1-4D5) antibody had inhibitory effect on induction of immunoglobulin synthesis by PWM-stimulated B cells.

Antibodies, Monoclonal↗
PubMed1985

Three distinct antigen systems on human B cell subpopulations as defined by monoclonal antibodies.

Three novel antigen systems (L22, L23, and L24) expressed on human B cell subpopulations were identified by using TB1-2C3, TB1-2B3, and TB1-3C1 monoclonal antibodies, respectively. L22 was expressed on a minor subpopulation of B cells in human lymphoid tissues and in the peripheral blood. These B cells associated with L22 were resting small B cells mainly located in the mantle zone of lymphoid follicles, most of which also expressed IgM and IgD on their cell membrane. This antigen was absent from all cultured hemopoietic cell lines including B cell-derived cell lines as well as from all human B cell malignancies, except for B cell-type chronic lymphocytic leukemia and hairy cell leukemia. L23 and L24, on the other hand, existed on approximately two-third of B cells in blood and lymphoid tissues. These L23 and L24 antigens were expressed largely on small lymphocytes located in the mantle zone of lymphoid follicles and to a lesser extent on large blastic cells within lymphoid germinal centers. L23 and L24, like L22, seem to disappear from B cells during their differentiation into antibody-secreting cells, because they were not expressed on normal and neo-plastic plasma cells. This is additionally confirmed by the observation that L23 and L24 were expressed little or not at all on pokeweed mitogen-activated and Epstein-Barr virus-transformed B cells, and were absent from some of B cell malignancies that have been thought to correspond to the later stages of B cell development. Although L23, but not L22 and L24, was faintly expressed on mature granulocytes and monocytes, none of L22, L23, or L24 existed on human thymus and T cells. Immunoprecipitation studies showed that L23 and L24 were different molecular species consisting of a single glycoprotein with m.w. of 205,000 and 145,000, respectively. L22 antigen is presently under study.

Antibodies, Monoclonal↗
PubMed1984

Mesangial immune deposits induced in rats by antibodies to fibronectin.

Immune deposits in the glomerular mesangium were induced in rats by injection of rabbit antibodies to rat plasma fibronectin (FN). By direct immunofluorescence and electron microscopy, deposits of immunoglobulins were detected in the mesangium of all rats injected with anti-FN IgG but not of control rats injected with normal rabbit IgG. By light microscopy, kidneys obtained 20 days after the antibody injection appeared to be normal. No proteinuria was detected during the experiment. Tissue uptake studies combined with direct immunofluorescence examination suggest that the initial accumulation of rabbit immunoglobulins in the glomerular mesangium is probably due to direct local binding of anti-FN antibody rather than trapping of immune complexes formed in the circulation. Quantitation of the direct binding using an in vivo perfused kidney system indicate that only a small fraction of the injected antibodies (less than 1 microgram/kidney) could bind. These studies indicate that (1) mesangial immune deposits may be induced by injection of antibodies to a glycoprotein, fibronectin, which is a normal structural component of the mesangium; (2) the initial accumulation of immunoglobulins in the mesangium is probably related to an in situ binding; and (3) mesangial antigens might be involved, in certain cases, in autoimmune reactions.

Animals↗
PubMed1984

Two distinct antigen systems in human B lymphocytes: identification of cell surface and intracellular antigens using monoclonal antibodies.

Two distinct antigen systems (L26 and L27) specifically expressed in human B lymphocytes were identified using TB2-2B3 (2B3) and T3-5B3 (5B3) monoclonal antibodies, respectively. Whereas L26 antigen defined by 2B3 were rarely expressed on the surface of B cells but abundant in the cytoplasm, 127 antigens detected by 5B3 was clearly expressed on the cell surface. These two antigens appeared to be restricted in their expression to B cells, as they were found in most B cells but not other cell types including thymocytes, T cells, monocytes and granulocytes. Functional studies demonstrated that L27 was more easily lost from B cells after activation with pokeweed mitogen than was L26. Likewise, plasma cell myeloma, as well as normal plasma cells, was devoid of both L26 and L27, whereas immunoblastic sarcoma of B cell type expressed L26 but not L27. These two antigens co-existed in the same B cell lines including Epstein-Barr virus transformed B cell lines, B cell type acute lymphatic leukaemia (B-ALL) cell line, Burkitt's lymphoma cell lines and myeloma cell lines, but pre-B and common ALL cell lines were entirely negative for both L26 and L27. Immunoprecipitation studies showed that L26 consisted of at least two polypeptide chains with molecular weights of 30K and 33K daltons, which were clearly distinct from HLA-DR antigens. The antigen L27 is presently under study.

Antibodies, Monoclonal↗
PubMed1984

Two closely related antigens expressed on granulocytes, macrophages and some reticular elements in rat lymphoid tissues: characterization by monoclonal antibodies.

Two distinct novel antigen systems preferentially expressed in rat granulocytes and macrophages were detected using two different monoclonal antibodies (R2-1A6 and R2-2B1). These two antibodies reacted with approximately 50% of rat bone marrow cells, most granulocytes, blood monocytes, alveolar macrophages and peptone-elicited peritoneal macrophages, but not with red blood cells, platelets, thymocytes and T lymphocytes. In addition, R2-2B1 but not R2-1A6 antibody cross-reacted weakly with rat B cells. These two monoclonals also reacted with some reticular elements in rat lymphoid organs including epithelial reticular cells in the thymic medulla and follicular dendritic cells in the lymphoid germinal centre, as well as with the specialized endothelium in the marginal sinuses of the spleen and the post-capillary venules of the lymph node, where lymphocyte recirculation takes place. These antibodies, however, did not label so-called 'dendritic cells' bearing Ia antigens on their cell surfaces, which were found to be located in the thymic medulla, thymus-dependent areas of rat lymphoid tissues and the interstitium of various non-lymphoid organs, suggesting that these dendritic cells, presumably ascribed to those associated with accesory cell function, are separable from the mononuclear phagocyte system in rats by their different reactivities with R2-1A6 and R2-2B1 antibodies.

Animals↗
PubMed1984

Rat T lymphocyte antigens comparable with mouse Lyt-1 and Lyt-2,3 antigenic systems: characterization by monoclonal antibodies.

Rat T lymphocyte antigens were defined by using two distinct monoclonal antibodies (R1-3B3 and R1-10B5). R1-3B3 antibody, when tested for its reactivity with rat lymphoid cells by immunofluorescence, stained almost all of thymus and T cells but not the majority of B cells and bone marrow cells. The antigen defined by R1-3B3 existed more abundantly on medullary thymocytes and peripheral T cells than on cortical thymocytes. Immunochemical data showed that R1-3B3 antibody recognized a single glycoprotein with a m.w. of 67,000, showing marked electric charge heterogeneity with isoelectric points ranging from 5.4 to 7.3. R1-10B5 antibody, on the other hand, had more restricted reactivity with rat T cells and labeled approximately 85% of thymus cells and 30% of the peripheral T cells but neither B cells nor bone marrow cells. These T cells positive for R1-10B5 appeared to be negative for W3/25 antigen, which has been shown to be the marker for the rat T cell subset associated with helper function. R1-10B5 antibody detected a basic glycoprotein complex consisting of sulfhydryl-linked subunits with 30,000 and 34,000 m.w. Although the antigen defined by R1-3B3 was resistant to trypsin digestion, the one detected by R1-10B5 was much more sensitive to trypsin cleavage. All of these data obtained with either R1-3B3 or R1-10B5 are quite comparable to those reported for mouse Lyt-1 or Lyt-2,3 antigens, and thus suggest that the antigens defined by R1-3B3 and R1-10B5 antibodies represent rat homologues of Lyt-1 and Lyt-2,3 antigens in the murine system, respectively.

Animals↗
PubMed1984

Lymphoid cell subpopulations infiltrating into autologous rat tumors undergoing rejection.

Lymphoid cell subpopulations infiltrating into autografts of methylcholanthrene-induced sarcomas in rats immunized with autologous tumor cells were identified in terms of immunohistochemical and cytofluorographic techniques using various monoclonal antibodies raised against different classes of rat lymphohemopoietic cells. These antibodies included in this study directed to rat T-cell antigens corresponding to mouse Lyt-1 (RLyt-1) and Lyt-2,3 antigens (RLyt-2) and to W3/25 antigen expressed on a particular subset of rat T-cells with helper function, as well as to rat granulocyte-macrophage-specific antigen (RGM-1). Histological studies demonstrated that the autografts of highly antigenic tumors introduced to the primary hosts were completely rejected following massive immigration of lymphoid cells into the tumor sites, which was not observed in progressively growing, minimally antigenic tumors. These lymphoid cells found within regressing highly antigenic tumor autografts were identified mostly to be T-cells bearing RLyt-1 (approximately 70%), and more than two-thirds of these T-cells expressed RLyt-2 antigen. In contrast to T-cells, macrophages and B-cells, each of which could be recognized by the presence of either RGM-1 antigen or immunoglobulin on their cell surfaces, appeared to have a minimal role in the rejection of autochthonous tumors, as reflected by their less frequent appearance within the tumor tissues during the rejection process.

Animals↗
PubMed1983

[A simple method for radioimmunoassay of total estrogen in urine].

A simple and rapid radioimmunoassay (RIA) without extraction or purification was developed for Total Estrogen (conjugated and unconjugated estrogen) in urine from normal men and nonpregnant women. Antiserum used to RIA was produced by immunizing rabbits with estriol-16 alpha-glucuronide (E3-16-G)-BSA conjugates. Antiserum to E3-16-G.BSA significantly cross-reacted with E1 (100%), E2 (100%), E3 (100%), E3-16-G (100%), AND E3-17-G (100%) and did not react with other conjugated estrogen in urine. Urinary estrogen glucuronides and sulfates were gently hydrolyzed by beta-glucuronidase from Helix pomatia juice for 2hr (48 degrees C) without inhibition, and hydrolysis urine was directly applied to RIA. The results obtained from this direct method correlated well with the chromatographic purificating method, the extracting method and the Brawn-Kambegawa method (colorimetric method). This direct method is very useful for clinical application.

Estriol↗
PubMed1983

Two distinct antigenic markers for rat thymus and T cells defined by monoclonal antibodies.

Rat thymus and T-cell antigens were defined by using two distinct monoclonal antibodies (R-1-3B3 and R-1-12C5). R-1-3B3 antibody, when tested for its reactivity with rat lymphoid cells by immunofluorescence, labelled virtually all thymus and T cells but not B cells and bone marrow cells. The antigen defined by this R-1-3B3 antibody occurred more abundantly on medullary thymocytes and peripheral T cells than on cortical thymocytes. Immunochemical data showed that R-1-3B3 antibody recognized a single glycoprotein with a molecular weight of 67,000, which were able to interact with Lens culinaris haemagglutinin. R-1-12C5 antibody, on the other hand, reacted with all of thymus and T cells as well as with a subpopulation (approximately 20%) of bone marrow cells. In contrast to the antigen defined by R-1-3B3, that detected by R-1-12C5 antibody existed largely on cortical thymocytes and to a much lesser extent on medullary thymocytes and peripheral T cells. R-1-12C5 antibody detected a single glycoprotein with a 95,000 molecular weight, which could also interact with Lens culinaris haemagglutinin. Based on these data described above and since both antigens defined by R-1-3B3 and R-1-12C5 antibodies were absent from rat brain tissue, we concluded that they were distinct from brain-associated thymic antigens in rats including Thy-1 and W3/13 antigen systems.

Animals↗
PubMed1982

Nasal T-cell lymphoma as a type of so-called "lethal midline granuloma".

Six cases were described in which an initial clinical diagnosis of "rhinitis gangrenosa progressiva" or lethal midline granuloma was made. The histological examinations of their surgical and autopsy specimens proved that their nasologic diseases could all be identified as malignant lymphoma arising from the nasal cavity, showing the general histologic characteristics reported for T-cell lymphomata derived from peripheral T-cells. This histologic observation was then confirmed by immunofluorescence studies using various antisera directed toward either human T- or B-cell-surface antigens. These studies clearly demonstrated that their malignant cells bore human Ly-l-like antigen but lacked human TL-like and Ia-like antigens as well as surface-bound immunoglobulins, indicating their peripheral T-cell origin. These data may suggest that so-called "rhinitis gangrenosa progressiva" or lethal midline granuloma contains at least two distinct disease categories, one of which is Wegener's granulomatosis, and the other of which is nasal T-cell lymphoma as described herein.

Antigens, Neoplasm↗
PubMed1982

Genetic control of autoantibody production to spermatozoa in vasectomized rats.

Previous studies from our laboratory using vasectomized rats of different inbred strains have suggested that MHC-linked genes do not play a major role in the formation of autoantibodies to spermatozoa. In the present paper, we demonstrate that sperm autoantibody product in is not influenced by genes in major histocompatibility complex, using vasectomized congenic rats and various crosses between high and low responder strains. We also show that autoimmune responses to spermatozoa are not influenced by genes on the Y-chromosome.

Animals↗