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Biomedical subjects

D Mizuno

Publications and source records attributed to D Mizuno.

At least 127 records · Page 7Linked to original sources
PubMed1981

Carbohydrates may play an important role in the interaction between phagocytic vesicles and lysosomes.

Agglutination of phagocytic vesicles by plant lectins and lysosomes from guinea pig polymorphonuclear leukocytes (PMNs) were examined in vitro. PMNs were allowed to phagocytize paraffin oil emulsion, and phagocytic vesicles were isolated from the cells. First, the vesicles were suspended in isotonic sucrose or lactose with or without lectins, and then they were incubated at 0 degrees C for 20 min and photographed under a phase-contrast microscope. In sucrose, lectins such as Ricinus communis agglutinin, wheat germ agglutinin, Phaseolus vulgalis agglutinin-P and Ulex europeus agglutinin agglutinated the vesicles, while the vesicles without lectins remained dispersed. Concanavalin A agglutinated the vesicles in lactose solution, but the other lectins did not. These results suggest that the phagocytic vesicles have lectin receptors (carbohydrate moieties) on their cytoplasmic side, as galactosyl-, N-acetyl-galactosaminyl-, mannosyl-, glucosyl-, N-acetylglucosaminyl- and di-N-acetylchitobiose residues. Second, the phagocytic vesicles were incubated with lysosomes. Lysosomes induced agglutination of the vesicles immediately after incubation and this agglutination was inhibited by simultaneous addition of 50 mM mannose, fucose, N-acetylglucosamine, lactose and maltose, and 7 mM N-acetylneuraminic acid and 1.25 mg/ml fetuin. The results show that lysosomes agglutinated the phagocytic vesicles in vitro, and suggest that this interaction is mediated by recognition of the carbohydrate moieties on the vesicles.

Agglutination↗
PubMed1981

Typing of immunomodulators in terms of their effects on the electrophoretic pattern of serum proteins and antitumor combination therapy based on this typing.

Changes of serum proteins have recently received much attention in studies of immunomodulators. In this work, changes of serum proteins, especially LB, were studied by gel electrophoresis of sera after administration of 23 immunomodulators or antitumor agents. Fourteen of the 23 compounds increased the concentration of LB in the serum of normal ddY mice when injected once ip. Six compounds caused a very rapid (day 1) increase of LB, and 8 agents caused a slow increase (day 4 approximately day 10). On the basis of the results, these compounds were classified into type I (causing a rapid increase in LB; i.e., lipopolysaccharide, dextran sulfate and poly (I)-poly(C), type II (causing a slow increase in LB; i.g., lentinan, TAK and PS-K), and type O (causing no increase in LB; e.g., levamisole and bestatin). The antitumor activities of these three types of compounds in combination with lipopolysaccharide (type I) or lentinan (type II) were studied in an Ehrlich carcinoma-ddY mouse system. The results suggested that different types of compounds frequently showed synergistic antitumor activities. Typing of immuno-modulators and the antitumor activities of combinations of these compounds are discussed.

Adjuvants, Immunologic↗
PubMed1981

Elimination of tumor-enhancing cells by cyclophosphamide and its relevance to cyclophosphamide therapy of the murine mammary tumor.

The antitumor effect of cyclophosphamide (CY) on a syngeneic mouse mammary tumor, MM46, was found to be due to selective elimination of host lymphoid cell populations as well as a direct cytotoxic effect of CY on tumor cells. marked inhibition of tumor growth after a single ip injection of CY on day 12 lasted for more than 3 weeks, unless the host was infused iv with spleen cells from tumor-bearing mice. The tumor-enhancing activity of spleen cells from tumor-bearing mice appeared to be mainly due to Thy 1.2 positive T lymphocytes and was no longer seen after CY treatment on day 12. The extent of tumor growth inhibition achieved with CY was critically dependent on the time of drug administration. CY had no antitumor effect when given before tumor inoculation. Associated with the antitumor effect of CY, augmentation of the antitumor delayed hypersensitivity reaction, or the cellular immune response, was observed. In contrast, the titer of antitumor antibody in the blood, or the humoral immune response, decreased. Cell transfer experiments showed that suppressor T cells for antitumor delayed hypersensitivity reaction specifically induced by the tumor inoculum were eliminated after CY treatment on day 12.

Animals↗
PubMed1980

Purification of lectin induced in the hemolymph of Sarcophaga peregrina larvae on injury.

A lectin was purified from the hemolymph of Sarcophaga peregrina larvae, obtained after injury of their body wall. This lectin agglutinated sheep red blood cells markedly and the hemagglutinating activity was inhibited by galactose and lactose. The active lectin was found to have a molecular weight of 190,000 and to consist of four alpha subunits and two beta subunits, with molecular weights of 32,000 and 30,000, respectively. During the early pupal stage, similar hemagglutinating activity in the hemolymph increased to several times than in larval hemolymph. This activity was completely inhibited by the antibody prepared against the lectin purified from the hemolymph of injured larvae. Thus, the same protein having lectin activity is apparently induced under two different physiological conditions: injury of the body wall of larvae and during pupation. The biological significance of this lectin is discussed.

Animals↗
PubMed1980

Induction of macrophage-mediated tumor lysis by the lectin wheat germ agglutinin.

The first step in macrophage-mediated tumor lysis, effector-target contact, was studied in a C3H/He mouse-MM46 syngeneic tumor system in which antibody-dependent tumor lysis by macrophages (ADMC) was observed in vitro. Various lectins were tested for the ability to mediate the contact between effector macrophages and target tumor cells. Several lectins, such as wheat germ agglutinin (WGA), concanavalin A, phytohemagglutinin, and pokeweed mitogen, were found to induce this contact, but only WGA also induced tumor lysis by macrophages. Both this lectin-dependent cytolysis by macrophages (LDMC) and the cytoadherence between macrophages and tumor cells induced by WGA were inhibited by N-acetyl-glucosamine, a sugar specifically recognized by WGA. In the LDMC reaction, macrophages in the presence of WGA could kill other syngeneic and allogeneic tumor cells but not normal thymus or spleen cells. These findings suggest that WGA is a ligand in macrophage-mediated cytolysis, inducing the binding of effector cells to target cells that triggers off lysis of the target cells. Comparative studies on the mechanisms of cytolysis involved in LDMC and ADMC showed that ADMC, but not LDMC, was inhibited by aggregated immunoglobulin and by protease pretreatment of macrophages. Thus, the mechanisms of recognition in LDMC an ADMC are different, but both ligands can induce the lytic reaction.

Agglutinins↗
PubMed1980

Antibody-induced antigen redistribution on murine mammary tumor cells.

Syngeneic antitumor antibody induced the capping of tumor-associated surface antigens on murine mammary tumor cells. Immunofluorescence staining showed that capping was maximal after 2 approximately 4 hr, and then the capped antigen-antibody complexes disappeared. Radioimmunoassay, however, showed that the quantity of antigen-antibody complexes was the same before and after capping. This redistribution of surface antigens on the tumor cells had no effect on the time course of antibody-dependent macrophage-mediated tumor lysis (ADMC). Inhibition of antigen movement on the cell surface by glutaraldehyde treatment did not inhibit ADMC. These results suggest that syngeneic antitumor antibody induces the capping of surface antigens on murine mammary tumor cells, but that this dynamic redistribution of surface antigens is not correlated with the susceptibility of the cells to ADMC.

Animals↗
PubMed1980

Depression of macrophage function by lipoprotein from tumorous ascites.

Various tumorous ascites inhibited the antibody-dependent macrophage-mediated tumor lysis in vitro (ADMC) which had been found in a C3H/He mouse-MM46 tumor system. This inhibition of ADMC was due to functional depression of effector macrophages, evidenced by in vitro and in vivo pretreatment of effector cells with ascites lipoprotein. Ascites lipoprotein also had direct cytotoxicity against various cells, but in the ADMC system, two activities appeared separately; lower concentrations of lipoprotein caused inhibition of ADMC and higher one caused cytotoxicity to macrophages and tumor cells. The component of lipoprotein active in these two activities was the lipid moiety. These results suggest that lipoprotein in tumorous ascities depresses the function of macrophages resulting in the inhibition of ADMC and that lipid moiety is the essential component.

Animals↗
PubMed1979

Purification and preparation of antibody to RNA polymerase II stimulatory factors from Ehrlich ascites tumor cells.

An improved method was developed for purification of the protein termed S-II that specifically stimulates RNA polymerase II of Ehrlich ascites tumor cells. The specific activity of the final preparation was 400 000 units/mg of protein, which is about 30-fold higher than that of the previous preparation [Sekimizu, K., et al. (1976) Biochemistry 15, 5064]. The final preparation gave a single band on both sodium dodecyl sulfate and nondenaturing gel electrophoresis, and the protein extracted from the band on nondenaturing gel had stimulatory activity. S-II is a basic protein with a molecular weight of 40 500. The fundamental characteristics of S-II determined with the previous preparation were confirmed with completely purified S-II. A specific antibody to S-II was prepared. This antibody inhibited only the stimulatory activity of S-II and did not affect the activity of RNA polymerase II itself. Thus, S-II is probably not a component of the multimeric proteins of RNA polymerase II.

Animals↗