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Biomedical subjects

M Taniguchi

Publications and source records attributed to M Taniguchi.

At least 811 records · Page 45Linked to original sources
PubMed1976

Properties of antigen-specific suppressive T cell factor in the regulation of antibody response of the mouse. II. In vitro activity and evidence for the I region gene product.

An antigen-specific suppressive T cell factor, which was extracted from carrier-primed T cells, was further characterized in an in vitro secondary antibody response. The factor was capable of suppressing secondary IgG antibody response of primed spleen cells when it was added to the culture together with relevant antigen. The suppressive T cell factor was not released from primed T cells by a short-term culture with antigen, but was kept bound to the membrane of the residual cultured cells, only the physical disruption of which can release the T cell factor. The target of the suppressive T cell factor was determined as being the helper T cell, since the factor did not exert any effect in the absence of the helper T cell with identical specificity to that of the factor. The suppressive activity was completely absorbed with alloantisera specific for products of the I region of H-2 complex, although various anti-immunoglobulin antisera failed to do so. Close analysis of the specificity of alloantisera capable of absorbing the suppressor molecule indicated that the suppressive T cell factor may, in fact, be an I region gene product probably coded for by genes in I-A and/or I-B (including I-E) subregions.

Absorption↗
PubMed1975

Thermally induced conformational changes of tobacco mosaic virus and their protein assemblies.

The measurement of the fluorescence intensity of tryptophan residues showed that a reversible transition in the local structure took place between 20 degrees C and 30c in intact virus particles and reconstituted protein assemblies of the ordinary strain and the tomato strain of tobacco mosaic virus. During this transition the overall polymer structure was maintained. In the case of the bean strain of tobacco mosaic virus, however, the fluorescence intensity did not show any transition in the same temperature range. Such a difference between different strains gave some information on the location of tryptophan residues possibly involved in the local structure change. The fluorescence polarization of intact virus particles showed no change in the whole temperature range, but the polarization of the reconstituted protein assembly of the ordinary strain showed a transition at the same temperature as the fluorescence intensity. This suggested a difference in the freedom of the local structure between intact virus particles and reconstituted protein assemblies. Oligomers of these virus proteins were stable up to 45c and above this temperature, began to make an irreversible transition where the secondary structure of the monomer was partially broken but the oligomer structure was retained.

Circular Dichroism↗
PubMed1975

Exchange of phospholipids between mitochondria and rough or smooth microsomes in vitro.

Phospholipids in mitochondria can be exchanged with those in two microsomal fractions from rough endoplasmic reticulum (rough microsomes) and smooth endoplasmic reticulum (smooth microsomes) in vitro in the presence of cell supernatant. The amounts of phospholipids transferred from each submicrosomal fraction to nitochondria were slightly different. The compositions of the phospholipids transferred to mitochondria from both microsomal fractions were the same, though these two fractions actually had different phospholipid compositions.

Animals↗
PubMed1974

Dual regulatory role of the thymus in the maturation of immune response in the rabbit.

Rabbits thymectomized in early adulthood produced more antihapten antibody than sham-thymectomized controls after hyperimmunization with 2,4-dinitrophenyl bovine gamma globulin (DNP-BGG). The average associated constant of anti-DNP antibody produced by thymectomized animals was more than 10 times higher than that of the controls. Similar effects were obtained by extensive treatment of rabbits with antithymocyte serum (ATS) before and during the immunization with DNP-BGG. The results indicated that relative diminution of thymus-derived lymphocytes (T cells) resulted in a stimulation of antibody-forming cells with a higher affinity. On the other hand, preimmunization of rabbits with different doses of BGG caused either enhancement or suppression of the hapten-specific antibody response, depending on the priming dose of BGG. The suppressed antibody response was always associated with a marked decrease in the antibody affinity. If rabbits were partially tolerized with a large dose of soluble BGG, some of the animals produced little antibody against hapten (DNP) coupled to this carrier, and the affinity of produced antibody was low. However, other rabbits tolerized with BGG produced large amounts of anti-DNP antibody upon hyperimmunization with DNP-BGG, whose affinity was only slightly lower than that of the control. These results can be harmonized if it is assumed that the thymus plays an important role in the maturation of the immune response. It is postulated that T cells, in numbers ordinarily available, would first assist in the proliferation of antihapten antibody-forming cell precursors already selected by antigen, thus accounting for the rapid increase of antibody affinity in the early stage of immunization. However, after a larger number of carrier-specific T cells are made in response to continued immunization, these would suppress antibody-forming cells. The suppression would be greater for cells with higher affinity for antigen, resulting in a decrease in antibody affinity. This postulate explains preferential stimulation and suppression of cells having higher affinity receptors under circumstances in which T cell are relatively depleted or overstimulated, and further permits an explanation for the decrease of antibody affinity after long-term immunization.

Animals↗