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T Tsumita

Publications and source records attributed to T Tsumita.

At least 37 records · Page 2Linked to original sources
PubMed1982

Activation of the alternative complement pathway of guinea-gip by liposomes incorporated with trinitrophenylated phosphatidylethanolamine.

By incorporation of trinitrophenylamino-caproyldipalmitoylphosphatidylethanolamine (TNP-Cap-DPPE) into liposomes composed of an equimolecular mixture of dimyristoylphosphatidylcholine (DMPC) and cholesterol (TNP-Cap-liposomes), liposomes became readily lysed by guinea-pig serum (GPS) in Mg++-EGTA-GVB (gelatin veronal buffered saline containing 2 mM MgCl2 and 10 mM ethyleneglycol-bis (beta-amino-ethyl ether)N-N'-tetraacetate) as well as in GVB++ (gelatin veronal buffered saline containing 0.15 mM CaCl2 and 0.5 mM MgCl2). Since the classical complement pathway (CCP) does not work in Mg++-EGTA-GVB, TNP-Cap-liposome lysis by GPS in Mg++-EGTA-GVB was thought to be mediated by the activation of the alternative complement pathway (ACP). This conclusion was supported by observations that heating of GPS at 50 degrees impaired its lytic activity while C4-deficient GPS was capable of lytic activity, no lysis occurred in EDTA, and there was noted consumption of complement in GPS treated with TNP-Cap-liposomes at 30 degrees. For TNP-Cap-liposome lysis by GPS in Mg++-EGTA-GVB, the epitope density of the TNP hapten was required to be 5% or more of the DMPC. Changing the acyl group of the phosphatidylcholine (PC) significantly influenced the ACP activating capacity of TNP-Cap-liposome. Dipalmitoyl-PC, DMPC and distearoyl-PC facilitated the ACP activating capacity of the TNP-Cap-liposome, while dilauroyl-PC, egg-PC and dioleoyl-PC did not. Furthermore, the length of spacer between TNP and dipalmitoylphosphatidylethanolamine (DPPE) also influenced the ACP activating capacity and maximum activation was noted when the spacer was aminocaproyl. These physicochemical characteristics which increase the ACP activating capacity coincided with those reported to increase the immunogenicity of hapten-sensitized liposomes.

Animals↗
PubMed1982

Effect of lipid A incorporation on characterization of liposomal model membranes as thymus-independent type 1 or type 2 immunogens.

We used the following criteria to determine whether liposomal model membranes are thymus-independent type 1 (TI-1) or type 2 (TI-2) immunogens: a) in vivo response of (CBA/N X BALB/c)F1 male and female mice; b) in vitro response of spleen cells from these mice; c) ontogeny of the response in cultures of (C57BL/6 X DBA/2)F1 male cells obtained from mice of different ages; d) ability of a monoclonal anti-delta antibody to block the in vitro response of C57BL/6 spleen cells. The liposomes were sensitized with N(2,4,6-trinitrophenyl-6-N-aminocaproyl)-dipalmitoylphosphatidylethanolamine (TNP-Cap-DPPE) and were prepared without and with incorporation of the B cell mitogen, lipid A. On the basis of the above criteria, liposomes prepared without lipid A can be characterized as a TI-2 immunogen and resemble TNP-Ficoll. In contrast, liposomes prepared with lipid A behave like a TI-1 immunogen such as TNP-BA (trinitrophenylated Brucella abortus). Conversion of liposomes from a TI-2 to a TI-1 immunogen by inclusion of lipid A in the bilayers was achieved under conditions of constant TNP-Cap-DPPE epitope density. Increasing the epitope density in liposomes made without lipid A does not result in transformation of immunogen type. These results, which bear on the features that may distinguish TI-1 from TI-2 immunogens, are discussed with regard to the involvement of macrophages and T cells in the response.

Animals↗
PubMed1981

Studies on lens proteins of mice with hereditary cataract. I. Comparative studies on the chemical and immunochemical properties of the soluble proteins of cataractous and normal mouse lenses.

Total soluble and insoluble proteins of the lens were similar in normal and hereditary cataractous mice up to 1 week of age. Thereafter, the normal mouse lens showed a continued increase in weight and protein content until 500 days of age. In cataractous mice, while the total protein content increased up to 60 days and reached a plateau, the soluble protein content declined dramatically from day 22 to day 60, and then the rate of decrease remained constant up to 500 days. At different ages, the soluble proteins were separated by gel filtration into the high molecular weight proteins, alpha-, beta- and gamma-crystallin fractions. All of these showed an age-related increase in the normal lens, and the relative values of alpha- and beta-crystallins increased for a 410-day period. On the other hand, in the cataractous process, the high molecular weight protein increased, and alpha-, beta- and gamma-crystallins decreased: the degree was especially marked in gamma-crystallin. Immunochemical studies indicated that the aggregation of beta-crystallin occurred much earlier in the cataractous lens than in the normal. Analysis of the amino acid composition and ultraviolet absorption spectra revealed no significant chemical differences between the crystallins of the normal and the cataractous lens.

Aging↗
PubMed1981

A simple method to measure anti-glycolipid antibody by using complement-mediated immune lysis of fluorescent dye-trapped liposomes.

A simple, reproducible, and micro quantity method is described to measure the antibody against glycolipid antigens. The multilamellar liposomes containing carboxyfluorescein (CF), which is self-quenched at high concentration, are prepared by vortexing the dried lipid films consisting of egg lecithin, cholesterol, phosphatidic acid and Forssman glycolipid antigen. On addition of anti-glycolipid serum plus active complement, liposome lysis occurs, and trapped CF is released. The dilution of CF in the external volume abolishes the quenching, resulting in a high fluorescence signal. Experimental conditions to measure anti-glycolipid antibody is established in this paper.

Animals↗
PubMed1979

A defect of the myo-inositol maintenance mechanism in the lens of hereditary cataract mice.

The myo-inositol uptake system was studied in lenses of normal and hereditary cataract mouse. The normal mouse was able to accumulate myo-inositol continuously from medium and keep it in a high concentration. The specific myo-inositol uptake was dependent on temperature and it decreased in Ca(2+)-free medium. In contrast, specific uptake of myo-inositol reached a plateau after 15 min in the cataract mouse lens although initial incorporation was more rapid than that in normal mouse lens. This uptake system was not affected by temperature or Ca(2+) in the medium. The rate of myo-inositol efflux into the medium was more rapid in the cataract lens than that of the normal lens. It was shown that the low level of myo-inositol in the lens of hereditary cataract mouse was due to the defect of myo-inositol transport system and the enhanced efflux rate. These results suggest a dysfunction of the lens membrane.

Animals↗
PubMed1977

myo-Inositol binding and transport in brush border membranes of rat kidney.

Using hypotonically treated brush border membranes, binding and transport of myo-inositol were examined. By hypotonic treatment, both total and non-specific uptake decreased significantly, but specific uptake was not affected. myo-Inositol release from membranes preloaded by incubation for 2 min was very rapid and about 98% of preloaded myo-inositol was released in 5 min of incubation. However, myo-inositol release from membranes preloaded by incubation for 20 min was fairly slow and 50% of myo-inositol remained in the membranes even after 10 min of incubation. Uptake of myo-inositol decreased by the increase of osmolarity in the medium. However, effect of osmolarity on the uptake was less significant when myo-inositol concentration was lower. Under conditions in which mainly binding occurred, myo-inositol binding to the membranes was measured. Two binding systems were demonstrated and high affinity site could bind 22 pmol/mg protein at most and the apparent Km value was 8.3 muM. Both binding and transport processes were dependent on Na+ and enhanced by Na+-gradient.

Animals↗
PubMed1975

Enhancement of encephalitogenic activity by the formation of myelin basic protein-brain acidic protein complex.

Encephalitogenic protein fraction (BEC) was isolated from bovine brain tissue by extraction with salt-ethanol mixture at neutral pH, instead of employing dilute mineral acid. The fraction BEC was separated into two fractions. An acid-soluble protein was encephalitogenic and the major component was very alike to the basic protein of myelin (Al). The other was acid-insoluble acidic protein that was not encephalitogenic even at a dose of 100 mug. The acidic protein formed an insoluble complex with Al rotein which was purified by Eylar's method. Encephalitogenic activity of the complex was higher than Al protein in young guinea pigs when injected with complete Freund's adjuvant.However, this enhancement of encephalitogenic activity was not observed in aged guinea pigs. The complex showed higher blastogenic activity than Al protein alone with peripheral blood lymphocytes from guinea pigs immunized with Al protein and complete Freund's adjuvant. These results show that an adjuvant-like acidic protein is present in brain tissue and the complex with Al protein enhances the induction of experimental allergic encephalomyelitis (EAE).

Age Factors↗
PubMed1975

Experimental allergic encephalomyelitis (EAE) in mice. I. Induction of EAE with mouse spinal cord homogenate and myelin basic protein.

The condition of experimental allergic encephalomyelitis (EAE) induction was investigated in several mice strains. SJL and C3H/He strains were found to be susceptible. A single immunization with mouse spinal cord, complete Freund's adjuvant (CFA) and pertussis vaccine produced clinical signs of EAE in SJL and C3H/He strains after 11 to 18 days. Isogenic spinal cord produced EAE in C3H/He strain. A single immunization with myelin basic protein from bovine spinal cord in CFA and pertussis vaccine produced EAE in SJL strain. EAE susceptibility of SJL strain correlated with the amount of mycobacteria used for sensitization. It was necessary to give pertussis vaccine intravenously in all cases.

Animals↗