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Y Shinkai

Publications and source records attributed to Y Shinkai.

66 records · Page 4Linked to original sources
PubMed1988

Resistance of mouse cytolytic cells to pore-forming protein-mediated cytolysis.

Pore-forming protein (perforin, PFP) was isolated from a mouse large granular lymphocyte (LGL) [natural killer (NK-like)] cell line. Purified PFP lysed a variety of mouse tumor cell lines and helper T lymphocyte cell lines. However, LGL and cytotoxic T lymphocyte cell lines were resistant to PFP-mediated cell lysis. The presence of hemolytic activity in the granule was examined in these resistant cell lines. Four out of five of these resistant cell lines had hemolytically active granules. We determined whether NK cells freshly isolated from BALB/c nude mouse spleens were resistant to PFP-mediated cytolysis. Nylon column-passed spleen cells with an enriched content of NK cells exhibited more resistance than whole spleen cells. Moreover, when spleen cells were treated with PFP the remaining live cells showed enriched NK activity suggesting that normal peripheral cells with NK activity are resistant to PFP. These results indicate that cytolytic cells containing PFP have developed defense mechanisms to inhibit PEP-mediated cell lysis.

Animals↗
PubMed1988

Mouse immunoglobulin allotypes: multiple differences between the nucleic acid sequences of the IgEa and IgEb alleles.

To clarify the allotypic difference of the IgE antibody molecule, we determined the complete nucleotide sequence of the genes encoding the constant portion of mouse IgE of a (BALB/c) as well as b (B10.A) allotypes. A comparison of the sequences revealed that there were 12 single-base changes: 2 single-base changes in CH1 and CH2, 3 in CH3, and 7 in CH4. Five of them were silent changes, but seven resulted in amino acid substitutions. Although the silent changes are scattered through CH1 to CH4, the nonsilent substitutions were found only in CH3 (two substitutions) and CH4 (five). The allotypic determinant(s) that conventional antisera detect most likely reflects an amino acid difference(s) in CH3 and/or CH4.

Alleles↗
PubMed1988

Purification and characterization of decay-accelerating factor (DAF) from Raji cells.

Decay-accelerating factor (DAF), a membrane protein that regulates the complement system, was purified to homogeneity from lymphoblastoid (Raji) cells (DAF-R). It exhibited almost the same molecular weight as DAF from stroma of erythrocytes (DAF-S). Purified DAF-R, which could be reincorporated into cell membranes, accelerated the decay of the C3 convertases, in both the classical (C4b2a) and the alternative (C3bBb) pathways. This activity was completely inhibited by a monoclonal anti-DAF antibody, 1C6. From these results, DAF-R and DAF-S can not be distinguished; however, the decay-accelerating activity of DAF-R was much higher than that of DAF-S. 1C6 enhanced the binding of C3 to Raji cells by incubating with six purified components of the alternative pathway, whereas it did not induce the killing of Raji cells after a short incubation period. When antibodies against Raji cells were added to the above system, the blocking of DAF activity by 1C6 resulted in efficient killing of Raji cells by autologous complement. From these results, it is clear that DAF on nucleated cells plays an important role in protecting these cells from the damage caused by autologous complement.

Burkitt Lymphoma↗
PubMed1987

Molecular cloning of Lyt-3, a membrane glycoprotein marking a subset of mouse T lymphocytes: molecular homology to immunoglobulin and T-cell receptor variable and joining regions.

Lyt-3 is a membrane glycoprotein expressed on thymocytes and class I major histocompatibility complex-restricted cytotoxic T cells. Lyt-3 is expressed as a heterodimer with Lyt-2, and this complex is considered to be a homologue of the human Leu-2/T8 (CD8) that has been postulated to be a receptor for the class I major histocompatibility complex. We have determined the complete primary structure of Lyt-3 from the nucleotide sequence of its cDNA clones. Analysis of the predicted amino acid sequence indicates that the Lyt-3 polypeptide has a 21-amino acid leader peptide, and the mature protein consists of an NH2-terminal region of 146 amino acids, a transmembrane region of 27 residues, and a C-terminal region of 19 amino acids. The NH2-terminal 110 residues show clear homology to the T-cell receptor and immunoglobulin variable region sequences. In addition, Lyt-3 has 11 residues that have strong homology to the joining region sequences of the T-cell receptor and the immunoglobulin heavy and light chains. The presence of immunoglobulin variable- as well as joining-region-related sequences in Lyt-3 further supports the idea that these molecules may be recognition molecules belonging to the immunoglobulin super gene family.

Amino Acid Sequence↗
PubMed1987

Rabbit nephrotoxic nephritis: effect of a thromboxane synthetase inhibitor on evolution and prostaglandin excretion.

Accelerated anti-glomerular basement membrane nephritis was induced in rabbits, and the immunological, clinical and histological evolution studied in relation to urinary immunoreactive thromboxane B2 (i-TXB2) and immunoreactive prostaglandin E2 (i-PGE2) excretion. In control nephritic animals, urinary i-TXB2 increased 5-fold on day +1, but was normal again by day +5. The urinary i-TXB2 showed a positive correlation with creatinine clearance (CCr), proteinuria and anti-sheep immunoglobulin antibody. Urinary i-PGE2 excretion increased by 50% on day +1, but was indistinguishable later from controls. The effects of the specific thromboxane synthetase inhibitor OKY-046 on this model was studied. In non-nephritic control animals, OKY-046 did not affect the CCr, the urinary protein excretion or the number of monocytes in glomeruli but reduced the excretion of i-TXB2. Although OKY-046 markedly inhibited the i-TXB2 excretion throughout the experiment in nephritic animals, the creatinine clearances were significantly worse, the proteinuria greater, and the number of infiltrating monocytes greater at day +5; by day +10 there was no difference from controls. There was no evidence that TXB2 is involved in the induction of proteinuria, and increased PGE2 synthesis did not protect against later proteinuria and fall in creatinine clearance. Inhibition of thromboxane synthetase appears to make this model of nephritis worse, rather than better.

Acrylates↗
PubMed1987

Trial of platelet-derived growth factor antagonist, trapidil, in accelerated nephrotoxic nephritis in the rabbit.

The platelet-derived growth factor (PDGF) antagonist, trapidil, which also blocks the thromboxane and/or PG-endoperoxide receptor and is an inhibitor of thromboxane synthetase, was administered during rabbit accelerated nephrotoxic nephritis; the clinical and histological evolution was studied as well as urinary immunoreactive thromboxane (i-TXB2) and immunoreactive prostaglandin E2 (i-PGE2) excretion. Although the dose we used has been shown to be effective in vivo, and it inhibited the urinary i-TXB2 excretion on days 5 and 10, it neither inhibited the enhanced production of i-TXB2 on day 1, nor prevented the glomerular influx of monocytes on days 5 and 10. All clinical and histological data tend to be worse rather than better in trapidil-treated animals on days 5 and 10.

Animals↗
PubMed1982

Experimental glomerulonephritis induced in rabbits by horseradish peroxidase. Mesangial uptake and processing of immune complexes.

Phagocytosis of immune complexes by glomerular mesangial cells was studied in rabbits in which immune complex nephritis was induced with subcutaneously injected horseradish peroxidase (HRP). Polymorphonuclear leukocytes accumulated in the glomerular capillary lumina, and the mesangial matrix increased soon after the last injection of HRP. The HRP-anti-HRP immune complexes localized diffusely in the mesangial matrix, and some of the complexes were phagocytosed by mesangial cells. After 7 days, the complexes localized to the vascular pole of the glomerulus, but they could not be detected as electron-dense deposits by electron microscopy. These studies indicate the involvement of mesangial cells in phagocytosis and elimination of immune complexes in rabbits with HRP-anti-HRP immune complex nephritis.

Animals↗