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Biomedical subjects

K Yokomuro

Publications and source records attributed to K Yokomuro.

At least 55 records · Page 3Linked to original sources
PubMed1991

Detection of nephritis strain-associated streptokinase by monoclonal antibodies.

Monoclonal antibodies (MAbs) N-59 and RU-1 were produced by immunisation of mice with streptokinase secreted by Streptococcus group A, type 12, strain A374 isolated from a patient with post-streptococcal glomerulonephritis (PSGN) and were characterised by Western blot analysis. MAb N-59 recognised antigenic determinants shared by both nephritis strain-associated streptokinase (NSA-SKase) and streptokinase of Streptococcus group C (C-SKase); MAb RU-1 reacted only with NSA-SKase. All nephritis-associated group A streptococcal strains tested reacted with MAb N-59; 87.5% of these strains reacted with MAb RU-1. MAb N-59 reacted with SKase produced by group G streptococcal strains isolated from patients with PSGN, and MAb RU-1 recognised SKase in two out of three of these strains.

Animals↗
PubMed1991

[Hematolymphoid system in the liver--restoring mechanism of hemopoiesis in the regenerating liver].

For the study of immunological phenomena peculiar to liver transplantation, it would be important to know well hematolymphoid system in the liver. In this paper, we report the restoring mechanism of hemopoiesis in the murine regenerating liver. 1) We found hemopoietic stem cells (HSC) and wheat germ agglutinin positive cells (WAG-PC) in both fractions of peripheral blood lymphocytes (PBL) and intrahepatic lymphocytes (IHL) from untreated C3H/He mice. The numbers of HSC and WGA-PC in each fraction gradually increased after partial hepatectomy. This change was remarkable in the population of IHL, associated more strongly with the liver. Colonies, which were generated from IHL in a fibrin clot culture system, are mainly composed of granulocytes, macrophages and mast cells. 2) We found colony-stimulating activity not only in the culture supernatant of normal nonparenchymal liver cells but in that of normal parenchymal liver cells. Furthermore, we clarified that one of colony-stimulating factors in both culture supernatants is GM-CSF. This result suggests parenchymal liver cells also release cytokines such as GM-CSF. These facts show that hematolymphoid system in the liver is a complicated network, composed of parenchymal liver cells, nonparenchymal liver cells, hemopoietic stem cells, and other cell populations.

Animals↗
PubMed1990

[Liver regeneration and immune system--morphological and cytochemical studies of activated spleen cells during the liver regeneration after partial hepatectomy].

Morphological and cytochemical changes were investigated in spleen cells after 70% hepatectomy in mice. During liver regeneration after the hepatectomy, the spleen weight gradually rose to a peak at 6 day. In the spleen, the number of POD-positive myelocytic cells and NCAE-positive granulocytic cells also reached a peak 4 days after the operation and then decreased. On the other hand, ANBE-positive monocytic cells gradually increased up to 9 day and didn't decrease for this period. On day 9 of the culture, the boundary between the red and the white pulps of the spleen became unclear. In this spleen, the clusters of blast cells were sporadically observed. Splenic T cells cocultured with nonparenchymal adherent normal liver cell or nonparenchymal adherent normal liver cell supernatant developed into granulocyte colonies in earlier periods and monocyte colonies in later periods. These findings suggest that the factors released from liver cells may regulate strictly spleen cell activation. Blast cell formation in the culture with nonparenchymal adherent normal liver cell supernatant was amplified by anti interferon (alpha + beta) antibody. These facts indicate that the functional network of cytokines is formed by the interaction of various cytokines (IL-1, IL-6, CSF, IFN, etc.) in nonparenchymal adherent normal liver cell supernatant.

Animals↗
PubMed1988

Suppression of liver regeneration resulting from intravenous injection of splenic glass adherent cells activated by poly I:C.

Syngeneic spleen cells (SPCs) were treated with poly I:C in the presence of DEAE-dextran for 2 h in vitro for their activation (IC-SPCs). When these IC-SPCs were inoculated into 70% partially hepatectomized mice, liver regeneration of the mice was strongly suppressed. The extent of suppression was dependent upon the number of injected cells and upon the concentration of poly I:C for in vitro treatment. Among IC-SPCs, the suppressive activity was predominantly caused by splenic glass adherent cells pretreated with poly I:C (IC-SACs) than by pretreated splenic T cells (IC-T). IC-SACs additionally cultured without poly I:C for 24 h lost their suppressive activity; however, when they were cultured in the presence of indomethacin, they could retain their activity, and interleukin 1 (IL 1) activity in culture supernatant was greater in the group cultured with indomethacin than without it. These results suggest that the suppressive activity of IC-SACs was not solely caused by the poly I:C carried into the mice with IC-SACs but by the activated IC-SACs themselves. The peak of liver cell mitosis in mice injected with IC-SACs was delayed 24 h as compared with non-injected groups, but IC-SACs-injected mice did not lose their regenerative potential. These findings demonstrate that the activated immune system may have some regulatory effects on liver regeneration.

Animals↗
PubMed1988

Enzyme-linked immunosorbent assay of antibody to group A Streptococcus-specific C carbohydrate with trypsin-pronase-treated whole cells as antigen.

We describe the measurement by enzyme-linked immunosorbent assay of antibody to group A Streptococcus C carbohydrate in immunized rabbits and human sera, with trypsin-pronase-treated group A streptococcal whole cells used as the antigen. The optimal concentration of the enzyme-treated whole cells used to coat the wells was 2 x 10(7) cells per well. Rabbit antiserum diluted to 1:12,800 and human serum diluted to 1:1,000 were found to be the optimal concentrations for antibody measurement. Antibody that reacted with enzyme-treated whole cells in rabbit antiserum was absorbed with group A streptococcal whole cells, purified C carbohydrate, and N-acetylglucosamine only. Enzyme-treated whole cells did not react with anti-lipoteichoic acid antibody, and rabbit antiserum did not react with lipoteichoic acid. There was a highly significant correlation between the anti-C carbohydrate antibody titrated with enzyme-treated whole cells and that with purified C carbohydrate as antigen. The correlation coefficient for the immunoglobulin M (IgM) antibodies was r = 0.75, and for the IgG antibodies it was r = 0.77. When the IgG antibody titers to the enzyme-treated whole cells of the sera of patients with acute poststreptococcal glomerulonephritis and rheumatic fever were compared with those of sera of healthy individuals, the sera of patients with poststreptococcal sequelae had significantly higher titers than did healthy individuals. Although anti-C carbohydrate antibody in human sera mostly belonged to the IgG2 subclass, there was anti-C carbohydrate antibody that belonged to the IgG3 subclass in a certain percentage of patients with rheumatic fever and acute poststreptococcal glomerulonephritis.

Adolescent↗
PubMed1987

Antigen-specific T cell cluster formation on antigen-pulsed macrophage monolayers in mice.

We describe the quantitative measurement of antigen-specific clusters formed by antigen-pulsed macrophages and immunized T cells in mice. We have found the peripheral blood T cells show very little non-specific adhesion to macrophages in mice. By using this population of lymphocytes in the peripheral blood as the source of immunized T cells, we could quantitate antigen-specific cluster formation. On OVA-pulsed monolayers of peritoneal exudate macrophages from normal BALB/c mice, syngeneic peripheral blood T cells from donors immunized with the same antigen develop 20-40 clusters per 1,000 macrophages, whereas the same T cells on non-pulsed monolayers develop only 0-5 cluster-like accumulations of cells. On antigen-pulsed monolayers of macrophages from allogeneic (C57BL/6 or A/J) mice, clusters are developed only in the negative range (0-5/1,000 macrophages). Considering the observation by Braendstrup et al, these data seem to suggest that histocompatibility between macrophages and T cells is required to develop antigen-specific T cell clusters on antigen-pulsed macrophage monolayers, and that the genetic restriction of immune responsiveness may be directly expressed in this initial form of cellular interaction between antigen-bearing macrophages and specific T cells.

Animals↗
PubMed1987

Coronary arteritis in mice after systemic injection of bacterial cell wall peptidoglycan.

We examined cell wall peptidoglycan (PGL) derived from group A streptococcus and other bacteria for possible induction of coronary arteritis in mouse strains. The histological finding of the main trunk of the coronary arteries of BALB/c, DBA/1J, C57BL/6 and DBA/2 mice, which were given an intravenous injection of sonicated PGL fragments of st. pyogenes at 500 micrograms per mouse 4 times at intervals of 1 week, showed diffuse cellular infiltration in the vascular wall as well as perivascular space. Marked hyperplasia of the endothelial cells was noted and necrosis of the medial smooth muscle of the coronary artery also was observed. The elastica stain clearly demonstrated fragmentation and degeneration of the elastic fibers. The histological change of the originating site of the aorta also noted swelling or hyperplasia of the endothelial cells and perivascular cellular infiltration. PGL fragments of st. mutans, st. sanguis and s. aureus did not cause any heart lesions. Coronary arteritis induced by st. pyogenes PGL could be very useful as an experimental animal model of Kawasaki's disease.

Animals↗
PubMed1985

Regulation of immune response by preadministration of cells briefly pulsed with antigen in vitro. III. Functional change of antigen presenting cells.

An intravenous administration of syngeneic spleen cells (SPCs) caused the reduction of antigen presenting activity of splenic adherent cells (SACs). The antigen presenting activity of SACs was reduced 10 days after the intravenous injection of 5 X 10(7) antigen pulsed or antigen nonpulsed SPCs. In contrast, when mice were immunized 5 days after the intravenous injection of SPCs, antigen presenting activity was reduced in the mice injected with antigen pulsed SPCs, and not in the mice injected with antigen nonpulsed SPCs. This reduction was recovered by the administration of cyclophosphamide 3 days before the injection of antigen pulsed SPCs, suggesting that suppressor T cells played an important role in the reduction of antigen presenting activity.

Animals↗
PubMed1984

Suppression of IgE antibody response by preadministration of antigen-pulsed spleen cells. II. Characteristics of immediate tolerance induction.

Intravenous administration of syngeneic spleen cells (SPC), briefly pulsed with antigen in vitro, resulted in a profound state of IgE antibody unresponsiveness. One of the mechanisms of this unresponsiveness is responsible for an immediate tolerance which is induced without any suppressor cells. Characteristics of this immediate tolerance were investigated. Administration of antigen-pulsed spleen cells 4 h before the immunization, suppressed the production of IgE antibody triggered by the subsequent immunization. Pretreatment with cyclophosphamide had no effect on this rapid suppression, and this suppressive state could not be transferred to normal syngeneic recipients by the injection of spleen cells from the tolerant mice used in our experiment. These observations suggest that suppressor cells do not play an important role in immediate tolerance. The extent of this immediate tolerance induced by the injection of antigen-pulsed SPC depends on the number of antigen-pulsed SPC and the dose of antigen to which SPC had been exposed. Injection route of antigen-pulsed SPC has a great influence on the induction of immediate tolerance. The order of suppressive extent is intravenous, greater than intraperitoneal greater than subcutaneous. This suppression is specific to the antigen pulsed to SPC. Carrier-specific T cells are the major target of suppression in immediate tolerance. Antigen-pulsed T cells induce immediate tolerance most effectively in the subpopulations of SPC.

Animals↗
PubMed1983

Regeneration and the immune system. I. In vitro and in vivo activation of lymphocytes by liver regeneration and the role of Kupffer cells in stimulation.

When syngeneic lymphocytes and mitomycin C-treated regenerating liver cells, prepared from partially hepatectomized mice, are cultured together, the in vitro DNA synthesis is activated (sMLHLR: syngeneic mixed hepatectomized-liver cell-lymphocyte culture). The Ia+ Kupffer cells play an important role as stimulators in the response, since the stimulating activity of regenerating liver cells is lost either by the pretreatment with anti-Ia monoclonal antibody plus complement or by the removing Kupffer cells from them. The lymphocytes are also activated in vivo during liver regeneration following partial hepatectomy. When lymphocytes, prepared from hepatectomized mice, are cultured with regenerating liver cells, the lymphocytes are stimulated to accelerate their DNA synthesis in a manner typical of the secondary immune responses (secondary sMLHLR). In primary sMLHLR, the responder cells are mainly Lyt-1+, whereas, in secondary sMLHLR, they are mainly Lyt-2+. The mechanism of changing the Lyt phenotype of major responder cells from Lyt-1 to Lyt-2 during sMLHLR is discussed.

Animals↗