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Biomedical subjects

Y Kumazawa

Publications and source records attributed to Y Kumazawa.

At least 127 records · Page 7Linked to original sources
PubMed1984

Activation of distinct T cell subsets involved in IgM antibody response of mice by pertussis toxin from Bordetella pertussis strain Maeno.

T cell activation mechanisms in the spleen induced by pertussis toxin (PT) were investigated. The degree of T cell activation was judged from results of helper activity assessed by measuring the in vitro antitrinitrophenyl (TNP) IgM antibody response. When mice were injected intraperitoneally with 4 X 10(5) sheep erythrocytes (SRBC) and concomitantly given an intravenous injection with 10 micrograms of PT 4 days previously, significant generation of nonspecific helper T cells was observed unless primed T cells were stimulated in vitro with TNP-SRBC. Stimulation with TNP-SRBC resulted in marked suppression of helper activity because it induced generation of suppressor T cells specific for the carrier antigen.

Adjuvants, Immunologic↗
PubMed1984

Cell cycle requisite for vesicular stomatitis virus replication in T lymphocytes activated with concanavalin A.

The relationship between the development of virus plaque forming cells (V-PFC) and the blastogenic response of T cells activated with concanavalin A (Con A) was investigated in connection with the cell cycle using a modified virus plaque assay (VPA) which facilitated the quantitative detection of T lymphoblasts with low susceptibility to infection by vesicular stomatitis virus (vsv). The generation of V-PFC markedly decreased when DNA synthesis inhibitors such as thymidine, hydroxyurea and cytosine arabinoside (Ara C) were added to spleen cell cultures stimulated with Con A, while the addition of a mitotic inhibitor, Colcemid, to the cultures caused only partial reduction of V-PFC development. These results indicate that the S to G2 phases of the first cell cycle are essential for vsv-replication or V-PFC development in Con A activated T cells. However, vsv-replication in the activated T cells does not depend on the initial G1 phase during the blastogenic response since the morphological blast formation of activated T cells is not suppressed by treatment with DNA synthesis inhibitors.

Animals↗
PubMed1983

Biochemical and physicochemical characterization of a mitogen obtained from an oriental crude drug, Tohki (Angelica actiloba Kitagawa).

Chemical composition and physicochemical properties of an immunomodulator, which is a non-dialyzable and acetone precipitable material(s) extracted with hot water from Angelica actiloba KITAGAWA (Yamato Tohki) (AIP), were investigated. AIP was composed of about 90% sugar and 10% protein. The major polysaccharide was identified as pectic substance(s) because its main component sugars were found to be arabinose, glucose, and galacturonic acid by gas liquid chromatographic analysis. The pectic substance(s) was not concerned with the mitogenicity of AIP since the activity was similar before and after pectinase(endo-polygalacturonase) treatment. More than half of the mitogenicity was destroyed by acid or alkali treatment. With pronase treatment, the activity was not affected, but the molecular weight of the mitogen was lowered. In addition, the mitogenic substance was partially purified from AIP by pectinase treatment and Westphal's phenol/water fractionation. The partially purified mitogenic substance(s) was rich in protein. These facts suggest that the mitogenicity of AIP was carried by a heat stable and protease resistant protein.

Amino Acids↗
PubMed1983

High frequency detection of different T-cell subsets in mice by a modified virus plaque assay.

Different T-cell subsets participating in immune responses were detected at a high frequency by a modified virus plaque assay (VPA). By using the modified VPA, different activated T-cell subsets generated in primary immune responses, helper and suppressor T cells participating in antibody formation, and effector T cells involved in the delayed-type hypersensitivity (DTH) reaction were enumerated directly without in vitro antigen stimulation. The frequency of detection in immune systems used was 7.5-17.7 V-PFC/10(3) spleen cells. Although neither helper T cells for antibody formation nor effector T cells for DTH reaction were detected as V-PFC at a high frequency by the original VPA, it was also found in secondary immune response that Lyt 1 positive, antigen-specific helper and effector T-cell subsets, and cyclophosphamide (CY)-resistant precursors were enumerated at a high frequency by the modified VPA when the received in vitro antigen stimulation, and that the proliferative stage of these cells was critical for the development of V-PFC.

Animals↗
PubMed1982

Immunostimulating polysaccharide separated from hot water extract of Angelica acutiloba Kitagawa (Yamato tohki).

Separation of immunostimulating polysaccharide (ATP) from Angelica and its biological activities were investigated. AIP was separated as an acetone-insoluble and non-dialysable fraction from hot water extract obtained by heating the root of Angelica acutiloba in water at 95 degrees-98 degrees for 30 min. It is a water-soluble heteropolymer(s) consisting of uronic acid, hexose and peptide. The anti-tumour activity of AIP was observed in terms of prolongation of the survival period of mice bearing Ehrlich ascites cells. The uptake of tritiated thymidine into murine and human spleen cells could be stimulated by AIP in a dose-dependent manner. Murine B cells were activated polyclonally by AIP and differentiated to anti-body-forming cells even in the absence of either helper T cells or macrophages. The possibility that the biological activity of AIP might be due to contamination by bacterial lipopolysaccharides (LPS) or lipid A-associated protein (LAP) was ruled out for the following reasons: (i) polyclonal B-cell activation by AIP was shown in spleen cell cultures of C3H/HeJ mice, a low responder strain to LPS; (ii) the activity of AIP disappeared completely after a mild periodate oxidation whereas that of LPS containing LAP was not lost by similar treatment. In addition, the primary antibody response to sheep-erythrocytes was markedly augmented by an intraperitoneal injection of AIP. This result show that AIP is a potent adjuvant.

Adjuvants, Immunologic↗
PubMed1982

Inhibition of macrophage function by 2-chloroadenosine.

The inhibitory action of 2-chloroadenosine (2-CA) on murine macrophages was investigated by means of concanavalin A (Con A)-induced T-cell proliferative response and of in vitro antibody response to sheep red blood cells (SRBC). The viability of peritoneal exudate cells (PEC) markedly decreased when treated with 0.1 mM 2-CA at 37 degrees C for 2 hr before cell cultures. Morphological changes were also observed in PEC treated with 2-CA. When spleen cells were treated with 2-CA or macrophages were depleted from the spleen cells, Con A-induced proliferative responses were markedly reduced unless normal spleen adherent cells (SAC) were added back to the cultures. However, reduced response could not be restored to the control level by the addition of 2-CA-treated SAC. AntiSRBC antibody response was also suppressed by pretreatment of spleen cells with 2-CA when adenosine was not present during the period of the treatment. Therefore, 2-CA is a useful cytotoxic agent for inhibiting the accessory functions of macrophages.

2-Chloroadenosine↗
PubMed1981

Experimental production of pulmonary granulomas. I. Immune granulomas induced by chemically modified cell walls and their constituents.

The intrabronchial instillation of stimulants in an oily vehicle induces a solitary inflammatory focus in the rabbit lung. When heat-killed tubercle bacilli were administered to tuberculo-immune animals, a necrotizing focus with cavities was induced. Delipidation of the bacterial cells stimulated the production of a necrotizing focus. In contrast, acetylation of the mycobacterial cell walls resulted in the replacement of cavity formation with epithelioid-cell granuloma production similar to that seen after the administration of Wax D, a peptidoglycolipid fraction of the cell walls. These lesions were induced much faster than in controls, indicating that some immune mechanisms are involved. In the present study of the specific granuloma induction mechanism, the biological activities of the chemical constituents of Wax D were examined. It was concluded that specific granuloma induction is due to the long delayed hypersensitivity antigenicity of Wax D which is brought about by the conjugation of biologically inactive mycolic acid with Arthus-antigenic peptidoglycan. Wax D glycolipids with delayed-type antigenicity also take part in the induction. The intrinsic adjuvant activity of these compounds may stimulate granuloma production. The haemagglutination antigenicity and Arthus-type antigenicity of the polysaccharide or peptidoglycan moiety are not involved.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1979

A B lymphocyte mitogen extracted from a fungus Peziza vesiculosa.

A water-soluble mitogen was extracted with hot-water from the fruiting bodies of a fungus, Peziza vesiculosa, collected in the wild. The active substance, named vesiculogen, was able to stimulate selectively murine B cells because mitogenic activity was observed in the spleen cell cultures of congenitally athymic nude mice, but not in the thymus cell cultures. The possibility that the mitogenicity of vesiculogen was due to lipopolysaccharide was denied completely by the following evidence: 1) lipopolysaccharide in vesiculogen was undetectable(less than 0.001% in the Limulus test), 2) vesiculogen was able to stimulate strongly DNA synthesis of spleen cells from C3H/HeJ mice, and 3) the mitogenic activity of vesiculogen was not inhibited by polymyxin B. Vesiculogen increased antigen-nonspecifically the number of direct plaque forming cells to sheep erythrocytes, horse erythrocytes, and trinitrophenylated-horse erythrocytes. This result shows that vesiculogen acts as a polyclonal B cell activator on murine spleen cells.

Animals↗