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K Inaba

Publications and source records attributed to K Inaba.

At least 127 records · Page 7Linked to original sources
PubMed1994

Synthesis and structure-activity relationships of 2,3-dihydrobenzofuran-7-carboxamide derivatives as potent serotonin-3 (5-HT3) receptor antagonists.

A series of N-(azabicyclo-3-yl)-2,3-dihydrobenzofuran-7-carboxamide derivatives were synthesized and evaluated for serotonin-3 (5-HT3) receptor antagonistic activities assessed by 5-HT3 receptor binding (in vitro) and by the ability to antagonize the von Bezold-Jarisch reflex in rats (in vivo). In these compounds, 1-azabicyclo[2.2.2]oct-3-yl derivatives were more potent than 8-methyl-8-azabicyclo[3.2.1]oct-3-yl derivatives for 5-HT3 receptor antagonistic activities. The introduction of methyl groups at position 2 of the dihydrobenzofuran ring increased the pharmacological activities (dimethyl > monomethyl > dihydro). Furthermore, the stereoisomers of dimethyl-, monomethyl-, and dihydrobenzofuran derivatives were prepared to evaluate the stereoselectivity of their 5-HT3 receptor binding affinities. Concerning the basic part, the compounds bearing (S)-1-azabicyclo[2.2.2]octan-3-yl moiety were more potent than their counterparts. With respect to the methyl substituent at position 2 of the dihydrobenzofuran ring, the rank order of the potency was dimethyl > or = (2S)-methyl > (2R)-methyl > dihydro. These results suggest that the (2S)-methyl group of the dihydrobenzofuran part contributes to the enhancement of the pharmacological activity. Among these compounds, (S)-N-(1-azabicyclo[2.2.2]oct-3-yl)-5-chloro-2,3-dihydro-2,2- dimethylbenzofuran-7-carboxamide hydrochloride (24) showed the highest affinity for 5-HT3 receptors (Ki = 0.055 nM), and the most potent antagonistic activity on the von Bezold-Jarisch reflex (ED50 = 0.18 microgram/kg i.v.).

Animals↗
PubMed1993

Dendritic cell progenitors phagocytose particulates, including bacillus Calmette-Guerin organisms, and sensitize mice to mycobacterial antigens in vivo.

Dendritic cells, while effective in sensitizing T cells to several different antigens, show little or no phagocytic activity. To the extent that endocytosis is required for antigen processing and presentation, it is not evident how dendritic cells would present particle-associated peptides. Evidence has now been obtained showing that progenitors to dendritic cells can internalize particles, including Bacillus Calmette-Guerin (BCG) mycobacteria. The particulates are applied for 20 h to bone marrow cultures that have been stimulated with granulocyte/macrophage colony-stimulating factor (GM-CSF) to induce aggregates of growing dendritic cells. Cells within these aggregates are clearly phagocytic. If the developing cultures are exposed to particles, washed, and "chased" for 2 d, the number of major histocompatibility complex class II-rich dendritic cells increases substantially and at least 50% contain internalized mycobacteria or latex particles. The mycobacteria-laden, newly developed dendritic cells are much more potent in presenting antigens to primed T cells than corresponding cultures of mature dendritic cells that are exposed to a pulse of organisms. A similar situation exists when the BCG-charged dendritic cells are injected into the footpad or blood stream of naive mice. Those dendritic cells that have phagocytosed organisms induce the strongest T cell responses to mycobacterial antigens in draining lymph node and spleen. The administration of antigens to GM-CSF-induced, developing dendritic cells (by increasing both antigen uptake and cell numbers) will facilitate the use of these antigen-presenting cells for active immunization in situ.

Animals↗
PubMed1993

Granulocytes, macrophages, and dendritic cells arise from a common major histocompatibility complex class II-negative progenitor in mouse bone marrow.

The developmental origin of dendritic cells, a specialized system of major histocompatibility complex (MHC) class II-rich antigen-presenting cells for T-cell immunity and tolerance, is not well characterized. Granulocyte-macrophage colony-stimulating factor (GM-CSF) is known to stimulate dendritic cells, including growth and development from MHC class II-negative precursors in suspension cultures of mouse bone marrow. Here we studied colony formation in semi-solid methylcellulose cultures, a classical bioassay system in which GM-CSF induces the formation of mixed granulocyte-macrophage colonies. When colonies were induced from MHC class II-negative precursors, a small subset (1-2%) of typical dendritic cells developed alongside macrophages and granulocytes. The dendritic cells were distinguished by their cytologic features, high levels of MHC class II products, and distinct intracellular granule antigens. By using differential adherence to plastic, enriched populations of the various myeloid cell types were isolated from colonies. Only the dendritic cells stimulated a primary T-cell immune response, the mixed leukocyte reaction, and the potency was comparable to typical dendritic cells isolated from spleen. Macrophages from mixed or pure colonies were inactive as stimulator cells. Therefore, three distinct pathways of myeloid development--granulocytes, macrophages, and dendritic cells--can develop from a common MHC class II-negative progenitor under the aegis of GM-CSF.

Animals↗
PubMed1993

Effects of intrathymic injection of organ-specific autoantigens, parietal cells, at the neonatal stage on autoreactive effector and suppressor T cell precursors.

Thymectomy on day 3 after birth (3d-Tx) induces autoimmune gastritis (AIG) in 81%, and oophoritis (AIO) in 25% of BALB/c mice at the age of 2 to 3 months. Intrathymic, but not intraperitoneal injection of syngeneic parietal cells into sex-matched BALB/c mice within 24 h of birth resulted in almost complete prevention of the development of AIG in these mice in which 3d-Tx was performed. The prevention induced was parietal cell specific, since the development of AIO was not inhibited in female mice. Moreover, the injection of BALB/c liver cells, Mls-matched (BALB/c) and -disparate (DBA/2) B blasts which resulted in V beta 6 T cell deletion, as well as the injection of staphylococcal enterotoxin B failed to prevent the diseases. These findings suggested that recognition of an autoantigen in the thymus is necessary for the induction of tolerance, and that involvement of Mls-1 antigens in the pathogenesis of AIG, as has been suggested previously (Schwartz, R. H., Cell 1989. 57: 1073), was unlikely. T cells that suppress the development of organ-specific autoimmune diseases in 3d-Tx mice seem to maintain the unresponsiveness of autoreactive T cells at the periphery in normal mice. In agreement with our previous observations, we found that intraperitoneal (i.p.) injection of spleen cells from 3-month-old normal mice into 3d-Tx mice on day 10 after birth prevented the development of AIG, whereas spleen cells from age-matched AIG+ (mice with AIG) or AIG- (mice without AIG) 3d-Tx mice failed to do this. This implies that the suppressor cells probably affect the differentiation of effector-precursor to effector. In fact, these suppressor cells did not inhibit the adoptive transfer of AIG to nu/nu BALB/c mice by spleen cells from 3d-Tx mice manifesting AIG. By negative selection using monoclonal antibody and complement, it was confirmed that the phenotype of the suppressor cell was CD4. In contrast to 3d-Tx, 10d-Tx did not induce AIG, indicating the peripheralization of the suppressor cell by that time. On the other hand, intrathymic injection of parietal cells immediately after birth did not affect suppressor cell generation, implying that some T cells, including suppressor cells, escape thymus selection. We postulate that these cells correspond to the precursors of the autoreactive effector T cells and suppressor T cells that are present in normal mice.

Animals↗
PubMed1993

Sperm chemotaxis during the process of fertilization in the ascidians Ciona savignyi and Ciona intestinalis.

Ascidian sperm were activated and attracted to all of the surface of a whole egg. When the whole egg was separated into follicle cells, chorion and test cells, and the egg itself (naked egg), spermatozoa were activated and exhibited chemotaxis toward the vegetal pole of the naked egg. Such activation and chemotaxis were not observed around isolated follicle cells or chorion with follicle cells and test cells, suggesting that a substance released from the vegetal pole of the egg which activates the sperm and orients them to it in the perivitelline space. The chemotaxis index, which was calculated by a newly proposed method, showed that sperm-attracting activity vanished when the egg deformed, suggesting that the release of attractant through the plasma membrane is terminated at the time of fertilization. The supernatant of the egg suspension (egg seawater) showed strong sperm-activating and sperm-attracting activities, which were dialyzable, heat stable, and resistant to proteinases. Thus, these activities may be initiated by a nonproteinaceous small molecule. Spermatozoa which were previously activated with theophylline without the egg factor showed chemotactic behavior to the tip of the capillary in which egg seawater was enveloped. However, spermatozoa exhibited only activation around the tip of the capillary with theophylline. This indicates that sperm activation and chemotaxis could be controlled under a separative mechanism.

Animals↗
PubMed1993

Dendritic cells: antigen presentation, accessory function and clinical relevance.

Because of difficulties in isolation, it has taken some time to arrive at a reasonable outline of the dendritic cell system. With the international effort that is assembled here, the main features of this system are apparent. There are now several criteria that allow for dendritic cell identification, there is understanding of tissue distribution and the interconnections between different compartments, there is new data on the production and maturation components of this system, and there are many observations that help explain antigen presentation, T cell stimulatory function, and behaviour in situ. The contributions of our Dutch hosts should be stressed. Many have energized the study of lymphoid, mononuclear phagocyte, and dendritic cell systems. The beginnings were made by Koenig, Langevoort, Thorbecke and van Furth, continued with Veldman, Nieuwenhuis, Hoefsmit, Drexhage, van Ewijk, Dijkstra, Kraal, Kamperdijk, and now there are many investigators in the biology of antigen presentation, one understands why it is appropriate to be in Holland. Holland even geographically is a "dendritic cell" [Fig 4].

Acquired Immunodeficiency Syndrome↗
PubMed1993

Tolerizing mice to human leukocytes: a step toward the production of monoclonal antibodies specific for human dendritic cells.

Despite several attempts to isolate a mAb specific for human dendritic cells, none currently exists. Recent attempts have utilized an improved dendritic cell purification method to prepare immunogens and a rapid two-color flow cytometric screening procedure that allows large numbers of hybridoma supernatants to be examined in each fusion. Yet these improvements have also failed, yielding only hybridomas that bind "shared" antigens expressed by both dendritic cells and other leukocytes. Dendritic cells express many shared antigens, including CD45 [leukocyte common antigen], CD40, leukocyte [beta 2] integrins CD11a and CD11c, CD54 [ICAM-1], CD44 [Pgp-1], CD58 [LFA-3], and the B7/BB1 antigen. Therefore, we are attempting to bias the immune response toward rarer, dendritic cell-specific clones by tolerizing or immunosuppressing our animals to shared antigens. In one approach, adult mice held in barrier cages are injected with "nondendritic" cells and cyclophosphamide [CP], in order to ablate responding "nonspecific" B cell clones. Fifteen days after the last dose of CP, they are challenged with nondendritic cells. A week later they are bled, and serum antibody titers against nondendritic cells are determined by FACS, in order to demonstrate tolerance compared to controls injected with CP alone. In the second approach, neonatal mice are injected with human T lymphoblasts at birth, followed by boosting at 1 week. In adulthood, they are challenged sequentially with sheep erythrocytes [sRBC], then with T blasts, to demonstrate that they can respond to unrelated cells but not to tolerogenic cells. One week after each kind of challenge, mice are bled and serum antibody levels are determined for treated and sham-injected mice. When these two approaches were compared, CP led only to nonspecific immunosuppression, while neonatal injections produced selective, antigen-specific nonresponsiveness to the tolerizing T blasts.

Animals↗
PubMed1993

Analyses of thymic abnormalities in autoimmune-prone (NZW x BXSB) F1 mice.

Thymic abnormalities of autoimmune-prone (NZW x BXSB)F1 mice are investigated. After the onset of autoimmune diseases, severe thymic atrophy is observed. The atrophied thymus shows lower CD4+ CD8+ T cell and higher CD4+CD8- or CD4-CD8+ T cell counts than aged-matched normal strains or other autoimmune-prone (NZB x NZW)F1(B/WF1) mice; even at the age of 40 weeks, B/WF1 mice have a large number of double-positive cells and a small number of single-positive cells. Thymocytes in the atrophic thymus of (NZW x BXSB)F1 mice respond better than normal mice to T cell-mitogens (PHA and ConA). In addition, the single-positive T cells are J-11d-negative. These findings indicate that the atrophic thymus includes mature T cells and a large number of plasma cells and B cells; it therefore responds well to lipopolysaccharides. Experiments in reciprocal transplantation of the thymus and bone marrow between (NZW x BXSB)F1 and normal mice show that the thymic abnormalities are due to defects of the hemopoietic stem cells (HSCs) rather than either intrinsic abnormalities in the thymus or extrinsic abnormalities such as anti-thymus antibodies. It should be noted that the atrophic thymus recovers after transplantation of normal bone marrow cells; the atrophic thymus still has the capacity to induce the differentiation of normal T cells (including double-positive T cells) if normal HSCs are introduced.

Aging↗
PubMed1993

Purification of proteasomes from salmonid fish sperm and their localization along sperm flagella.

We have purified two chymotrypsin-like proteases from chum salmon sperm which have no apparent acrosome structure. Both of them were high molecular mass proteases (650 kDa and 950 kDa by gel filtration) and showed not only chymotrypsin-like activity but also trypsin-like activity. The 650 kDa protease was composed of at least eight or nine kinds of polypeptide with molecular masses ranging from 20 kDa to 30 kDa and was highly activated by low concentrations of SDS. Electron microscopy revealed that the 650 kDa protease was a ring-shaped particle. The 950 kDa protease was shown to contain at least one component that cross-reacts with an antibody against the 650 kDa protease. Finally, we revealed that the 650 kDa protease is located along the sperm flagella, by using immunofluorescence microscopy. The subunit composition, SDS-activation and molecular shape of 650 kDa salmonid protease were quite similar to those of the eukaryotic multicatalytic proteinase (proteasome), which is well known to participate in ATP-dependent degradation of ubiquitinated proteins; and, furthermore, the motility of demembranated sperm of salmonid fish is inhibited by chymotrypsin inhibitors in an ATP-dependent manner. Thus, the protease located in salmonid fish sperm flagella is a proteasome and is a strong candidate for the factor which regulates flagellar motility in an ATP-dependent manner.

Amino Acid Sequence↗
PubMed1993

Identification of macrophages and dendritic cells in the osteopetrotic (op/op) mouse.

We used a panel of monoclonal antibodies and immunocytochemistry to identify macrophages and dendritic cells in mice that are deficient in macrophage colony stimulating factor (M-CSF or CSF-1) because of the recessive osteopetrotic (op/op) mutation. Prior work had shown that osteopetrosis is associated with a lack of osteoclasts, phagocytic cells required for remodelling in bone. Additional macrophage populations proved to be very M-CSF dependent. op/op mice had few and sometimes no peritoneal cavity phagocytes, splenic marginal zone metallophils, and lymph node subcapsular sinus macrophages. Other populations, however, reached substantial levels in the absence of M-CSF, including phagocytes in the thymic cortex, splenic red pulp, lymph node medulla, intestinal lamina propria, liver (Kupffer cells), lung (alveolar macrophages) and brain (microglia). Dendritic cells, which are specialized accessory cells for T-dependent immune responses and tolerance, were readily identified in skin and in the T-dependent regions of spleen, lymph node and Peyer's patch. The identification of dendritic cells utilized antibodies to MHC class II products and four different antigens that are primarily expressed by these accessory cells. Our findings indicate that only a few macrophage populations are critically dependent upon M-CSF in vivo. With respect to dendritic cells, the data are consistent with prior in vitro work where it was noted that GM-CSF but not M-CSF supported dendritic cell viability, function and growth.

Animals↗
PubMed1993

Macrophages, but not dendritic cells, accumulate colloidal carbon following administration in situ.

The dendritic cell system operates in situ to capture and present antigens in a form that is immunogenic to T cells. It is likely that dendritic cells require endocytic activity in order to process antigens. On the other hand, macrophages are considered to be the principal cells that internalize substrates in situ. We therefore investigated the phenotype of cells that scavenge the indigestible endocytic tracer, colloidal carbon, by phenotyping the endocytic cells with monoclonal antibodies that help distinguish macrophages from dendritic cells. Of some importance was the monoclonal N418, an antibody to the p150/90 leukocyte beta 2 integrin. FACS analyses on isolates from blood, spleen and peritoneal cavity showed that N418 reacts primarily with dendritic cells. N418 also stained dendritic profiles strongly in tissue sections of liver and spleen, but most of the cells that actively endocytosed carbon in both organs showed little or no N418 staining. Likewise, carbon could not be identified in cells that react with M342, which stains intracellular granules of dendritic cells. In contrast, the carbon-labeled cells in both liver and spleen were labeled with antibodies (SER-4, F4/80, FA11) that bind primarily to isolated macrophages. Therefore the clearance of colloidal carbon in situ reflects the scavenging activity of macrophages and not the endocytic activity that underlies the antigen presenting function of dendritic cells.

Animals↗
PubMed1993

The effects of orally administered Y-25130, a selective serotonin3-receptor antagonist, on chemotherapeutic agent-induced emesis.

The antiemetic effects of orally administered Y-25130, a potent and selective 5-HT3-receptor antagonist, were compared with those of ondansetron, granisetron, metoclopramide and domperidone. Y-25130 (0.1-1.0 mg/kg) dose-dependently prolonged the latency to the first vomiting and decreased the number of vomitings induced by cisplatin in dogs. The antiemetic effect of Y-25130 against cisplatin-induced vomiting was more potent than that of metoclopramide and ondansetron, but it showed little difference from that of granisetron. The emesis induced by the combined treatment of doxorubicin and cyclophosphamide was also inhibited by Y-25130 (0.1-1 mg/kg) in ferrets. The antiemetic effect of Y-25130 was more potent than that of metoclopramide, almost the same as that of granisetron and less potent than that of ondansetron. Because of a notable difference of potency ranking between Y-25130 and ondansetron in these two tests, a third test was performed to evaluate the inhibitory effect of Y-25130 in ferrets on cisplatin-induced emesis in comparison with that of ondansetron. The antiemetic effect of Y-25130 on cisplatin-induced emesis in ferrets was very similar to that of ondansetron. Domperidone did not inhibit these cytotoxic agents-induced emeses. These results suggest that Y-25130 is an orally active antiemetic compound against cisplatin and doxorubicin/cyclophosphamide-induced emeses; and its the antiemetic potency is similar to those of granisetron and ondansetron, but superior to those of metoclopramide and domperidone.

Administration, Oral↗
PubMed1993

Functional analyses of B cells in (NZW x BXSB) F1 mice.

Functions of B cells from (NZW x BXSB)F1 (W/BF1) mice are investigated. The W/BF1 mouse, which is an animal model for systemic lupus erythematosus (SLE) and immune thrombocytopenic purpura (ITP), produces anti-DNA and anti-platelet antibodies; W/BF1 mice show hypergammaglobulinemia (particularly increases in IgG2a and IgG2b). The ratio of small resting B cells to large activated B cells in W/BF1 mice is low compared to normal mice, suggesting that B cells in W/BF1 mice are already activated in vivo. Furthermore, small resting B cells separated by a Percoll density gradient technique show hyper-responsiveness to lipopolysaccharide (LPS) or anti-mu plus IL-4. This suggests that B cells in W/BF1 mice are genetically programmed to be easily activated, resulting in the overproduction of autoantibodies. A significant number of CD5+ B cells are found in the lymph nodes of old W/BF1 mice. These findings indicate that all cells in the B cell lineage of W/BF1 mice are already activated in vivo.

Animals↗
PubMed1993

Low responsiveness of hepatitis B virus-transgenic mice in antibody response to T-cell-dependent antigen: defect in antigen-presenting activity of dendritic cells.

The experiments presented here were performed to evaluate immune responsiveness of hepatitis B virus (HBV)-transgenic mice (transgenic mice), as a model of HBV-carrier state to a T-cell-dependent antigen, keyhole limpet haemocyanin (KLH). The transgenic mice which were completely unresponsive to hepatitis B surface antigen (HBsAg), responded poorly to KLH. The levels of anti-KLH antibodies (Ab) produced in vivo were significantly lower in transgenic mice compared with the normal control mice at respective immunizing doses of KLH. In addition, a little or no anti-KLH Ab production was detected in culture supernatants of KLH-primed transgenic mice spleen cells. KLH-primed T cells from normal and transgenic mice induced anti-KLH Ab production from transgenic B cells in the presence of antigen-presenting spleen adherent cells (SAC) from normal mice, but not those from transgenic mice. Depletion of dendritic cells from normal mice-derived SAC completely abrogated the anti-KLH Ab response in transgenic spleen cell culture and their addition to the culture restored the response. Low efficiency of transgenic dendritic cells was demonstrated in sodium periodate (NaIO4)-induced non-specific and allogenic antigen-induced T-cell proliferation. Finally, cytofluorometric analyses showed a reduced Ia antigen expression on transgenic dendritic cells. These results indicate that low responsiveness of transgenic mice in specific-antibody response is not due to functional defects in T cells or B cells but rather to a defect of antigen-presenting activity of dendritic cells.

Animals↗
PubMed1992

Generation of large numbers of dendritic cells from mouse bone marrow cultures supplemented with granulocyte/macrophage colony-stimulating factor.

Antigen-presenting, major histocompatibility complex (MHC) class II-rich dendritic cells are known to arise from bone marrow. However, marrow lacks mature dendritic cells, and substantial numbers of proliferating less-mature cells have yet to be identified. The methodology for inducing dendritic cell growth that was recently described for mouse blood now has been modified to MHC class II-negative precursors in marrow. A key step is to remove the majority of nonadherent, newly formed granulocytes by gentle washes during the first 2-4 d of culture. This leaves behind proliferating clusters that are loosely attached to a more firmly adherent "stroma." At days 4-6 the clusters can be dislodged, isolated by 1-g sedimentation, and upon reculture, large numbers of dendritic cells are released. The latter are readily identified on the basis of their distinct cell shape, ultrastructure, and repertoire of antigens, as detected with a panel of monoclonal antibodies. The dendritic cells express high levels of MHC class II products and act as powerful accessory cells for initiating the mixed leukocyte reaction. Neither the clusters nor mature dendritic cells are generated if macrophage colony-stimulating factor rather than granulocyte/macrophage colony-stimulating factor (GM-CSF) is applied. Therefore, GM-CSF generates all three lineages of myeloid cells (granulocytes, macrophages, and dendritic cells). Since > 5 x 10(6) dendritic cells develop in 1 wk from precursors within the large hind limb bones of a single animal, marrow progenitors can act as a major source of dendritic cells. This feature should prove useful for future molecular and clinical studies of this otherwise trace cell type.

Animals↗
PubMed1992

The involvement of protein kinase C in activation-induced cell death in T-cell hybridoma.

T-cell hybridoma activated by a variety of stimuli such as anti-cell surface antigen, notably CD3 and T-cell receptors, and Con A undergoes a cell lysis process called activation-induced cell death (AICD). It was found that the major protein kinase C (PKC) isoform in the 2B4.11 T-cell hybridoma, PKC(alpha), was translocated from the cytosolic to the particulate fraction when these hybridoma cells were induced to die by plastic-adsorbed anti-CD3 antibodies. Inhibitors of protein phosphorylation rescued 2B4.11 cells from AICD as determined by the analysis of cellular metabolism and the proportion of living cells. Furthermore, PKC(alpha) down-regulation by phorbol ester treatment abolished AICD, and the degree of PKC down-regulation correlated well with the degree of AICD abolishment, suggesting that PKC activation represents an essential step in the molecular mechanisms underlying AICD in this T-cell hybridoma.

Alkaloids↗
PubMed1992

Dendritic cells exposed to human immunodeficiency virus type-1 transmit a vigorous cytopathic infection to CD4+ T cells.

The paucity of virus-laden CD4+ cells in individuals infected with human immunodeficiency virus type-1 (HIV-1) contrasts with the greatly reduced numbers and function of these lymphocytes. A pathway is described whereby dendritic cells carry HIV-1 to uninfected T cells, amplifying the cytopathic effects of small amounts of virus. After exposure to HIV-1, dendritic cells continue to present superantigens and antigens, forming clusters with T cells that are driven to replicate. Infection of the dendritic cells cannot be detected, but the clustered T cells form syncytia, release virions, and die. Carriage of HIV-1 by dendritic cells may facilitate the lysis and loss of antigen specific CD4+ T cells in acquired immunodeficiency syndrome.

Acquired Immunodeficiency Syndrome↗