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T Yokoi

Publications and source records attributed to T Yokoi.

At least 253 records · Page 14Linked to original sources
PubMed1989

Conformation-dependent recognition of a protein by T cells requires presentation without processing.

Presentation of a protein antigen to T cells is believed to follow its intracellular breakdown by the antigen-presenting cell, with the fragments constituting the trigger of immune recognition. It should then be expected that T-cell recognition of protein antigens in vitro will be independent of protein conformation. Three T-cell lines were made by passage in vitro with native lysozyme of T cells from two mouse strains (B10.BR and DBA/1) that had been primed with the same protein. These cell lines responded well to native lysozyme and very poorly to unfolded (S-sulphopropyl) lysozyme. The response of the T-cell lines to the antigen was major histocompatibility complex (MHC)-restricted. A line from B10.BR was selected for further studies. This line responded to the three surface-simulation synthetic sites of lysozyme (representing the discontinuous antigenic, i.e. antibody binding, sites) and analogues that were extended to a uniform size by a nonsense sequence. T-cell clones prepared from this line were specific to native lysozyme and did not respond to the unfolded derivative. Furthermore, several of these clones showed specificity to a given surface-simulation synthetic site. The exquisite dependency of the recognition by the clones on the conformation of the protein antigen and their ability to recognize the surface-simulation synthetic sites indicate that the native (unprocessed) protein was the trigger of MHC-restricted T-cell recognition.

Amino Acid Sequence↗
PubMed1989

Human identification and sex determination of dental pulp, bone marrow and blood stains with a recombinant DNA probe.

Recombinant DNA hybridizing specifically to a 300 nucleotide repeat DNA sequence (BLUR8) of human specificity and to human repeat DNA sequence (pHY10) on the Y chromosome was used for human identification and sex determination of degraded DNA samples of blood stains, dental pulp, and bone marrow. This radioactive technique enabled reliable and sensitive human and sex determination from blood stains that were more than 80 years old. Less than 1 piece of 0.5 cm length thread of blood stain was enough for both tests. DNA from relatively fresh dental pulp and bone marrow was clearly identified. The human identification test, which could recognize up to 0.3 ng DNA correctly, was 3 to 5 times more sensitive than the sex determination test.

Adolescent↗
PubMed1989

Hypervariable polymorphism of autosomal origin detected by the Y-chromosome derived probe, pHY10.

A recombinant DNA probe (pHY10) hybridizing specifically to human DNA family DYZ1, 3,000 copies of which are present on the long arm of the Y chromosome, was used for probing human genome DNA digested with various restriction enzymes. To our surprise, the probe detected a hypervariable polymorphism of autosomal origin in human DNA when digested with TaqI. None of other 12 restriction enzymes revealed polymorphic patterns. Codominant segregation of the polymorphism was established in family studies. This probe has been widely used in the detection of the Y chromosome. Its ease of availability as well as highly discriminating polymorphic pattern makes it potentially very useful for forensic and human genetic purposes.

DNA Probes↗
PubMed1989

Specific capture of ABH blood group antigens of the red cell or body fluids by double antibody sandwich-ELISA.

A double antibody sandwich-ELISA method for the detection of the ABH blood group of each constituent of mixed stains is described. Extracts from mixed stains were applied to microtitration plates coated with rabbit polyclonal antisera to red cells or body fluids. ABH antigens in body fluid stains which were captured by the polyclonal antibodies were detected by monoclonal anti-A and -B and enzyme-conjugated anti-mouse immunoglobulin. By this procedure, ABH antigens of only saliva, semen or red cells could be detected from mixed stains, but no ABH antigen capture activity was observed using anti-sweat, -milk, -vaginal secretion, -erythrocyte membrane and -band 3 antibodies.

ABO Blood-Group System↗
PubMed1989

The acute phase nature of interleukin 6: studies in Kawasaki disease and other febrile illnesses.

Interleukin 6 (IL-6) has manifold biological functions involved in the immune or inflammatory responses of the host to various stimuli. Here we asked whether IL-6 might be responsible for manifestations of Kawasaki disease (KD), such as immunoglobulin hypersecretion, lymphocyte activation and systemic vasculitis. IL-6 activity in the serum was determined by a sensitive colorimetric assay using an IL-6-dependent murine hybridoma clone. Usually sera from healthy or afebrile donors contained only negligible levels of IL-6 activity below the detection threshold of the assay. Importantly it was found that serum IL-6 was markedly elevated in all patients with acute KD. Serum levels of IL-6 activity gradually diminished during the course of the disease and reached undetectable or lower levels at the convalescent phase. However, such elevated levels of serum IL-6 activity were also observed in the majority of other febrile diseases, such as bacterial or viral infections, indicating that the appearance of IL-6 in the serum could generally occur in febrile or inflammatory disease conditions. Serum IL-6 activity correlated with serum concentrations of some acute phase proteins (APP), such as C-reactive protein, haptoglobin and alpha 1-acid glycoprotein, implying its role for modulating induction of APP in vivo. IL-6 is well known to be secreted by a variety of cell types. Further studies, including immunohistochemical analysis using anti-IL-6 antibody, will be necessary to examine whether the source of serum IL-6 in KD might be different from that seen in other diseases.

Acute-Phase Proteins↗
PubMed1989

Somatostatinoma of the rectum.

We report a case of a 29-yr-old man with a rectal carcinoid that metastasized to the liver, secreting somatostatin. The patient first presented with an abdominal mass and mild diabetes, and, subsequently, rectal tumor and hypersomatostatinemia. Microscopic examination of the rectal tumor showed characteristic features of carcinoid. Multiple liver metastases were recognized. The plasma level of somatostatin was remarkably high (2,839 pg/ml). Plasma gut glucagon and pancreatic polypeptide (PP) increased with progress of the disease. He died of hepatic failure 20 months after his first admission. Immunoperoxidase staining showed that rectal tumor cells contained somatostatin-like-immunoreactivity. Electron microscopy of tumor tissue showed neurosecretory (D-cell) granules. Somatostatin content of the rectal tumor was very high (5,629 pg/mg).

Adult↗
PubMed1988

Recognition of inter-transmembrane regions of acetylcholine receptor alpha subunit by antibodies, T cells and neurotoxins. Implications for membrane-subunit organization.

Three regions of the alpha chain of Torpedo californica acetylcholine receptor (AChR), corresponding to residues alpha 262-276, alpha 388, 408 and alpha 427-437 were synthesized, purified and characterized. The first two peptides have been proposed to occupy inter-transmembrane regions while the third represented the C-terminal segment, proposed by various models to be either extracellular or intracellular. Peptide alpha 388-408 stimulated a good response in the AChR-primed T cells of H-2s haplotype mice, a low response in the H-2q haplotype and no response in the H-2b haplotype. Peptide alpha 427-437 stimulated AChR-primed T cells of the H-2s haplotype, but caused no response in the q and b haplotypes. Peptide alpha 262-276 evoked no in vitro stimulation in any of the s, q or b haplotypes. In antibody binding studies, peptide alpha 388-408 bound antibodies raised against free AChR or against membrane-bound AChR. The other two peptides showed little or no binding activity. Further, peptide alpha 388-408 bound specifically both 125I-labelled bungarotoxin and cobratoxin, while the other two peptides had no binding activity. These results were consistent with only one of the models for subunit organization within the membrane.

Animals↗
PubMed1988

The regions of alpha-neurotoxin binding on the extracellular part of the alpha-subunit of human acetylcholine receptor.

A set of 18 synthetic uniform overlapping peptides spanning the entire extracellular part (residues 1-210) of the alpha-subunit of human acetylcholine receptor were studied for their binding activity of 125I-labeled alpha-bungarotoxin and cobratoxin. A major toxin-binding region was found to reside within peptide alpha 122-138. In addition, low-binding activities were obtained with peptides alpha 34-49 and alpha 194-210. It is concluded that the region within residues alpha 122-138 constitutes a universal major toxin-binding region for acetylcholine receptor of various species.

Amino Acid Sequence↗
PubMed1988

Major structural polypeptides of retrovirus produced by a Suncus murinus mammary tumor cell line and type D retrovirus share interspecies antigenic determinants.

Constitutive polypeptides of retrovirus produced by a Suncus murinus mammary tumor cell line (Sm-MTV) were characterized by immunofluorescence and immunoblotting. The major structural polypeptide of Sm-MTV, molecular weight 44/43K, immunologically cross reacted with the structural polypeptides of Mason-Pfizer monkey virus (MPMV) (molecular weights 27K and 12/10K). Sm-MTV constitutive polypeptides did not show antigenic relatedness with those of the following mammalian retroviruses: murine mammary tumor virus, Rausher murine leukemia virus, Molony murine leukemia virus, Osborn-Mendel rat leukemia virus, feline leukemia virus, RD114 virus, simian sarcoma virus 1, and human T-cell leukemia virus type I. Among the Sm-MTV structural polypeptides, those with molecular weights of 72/69K and 47K were glycosylated.

Animals↗
PubMed1988

Polygonal networks, "geodomes", of adult rat hepatocytes in primary culture.

Polygonal networks, "geodomes", in cultured hepatocytes of adult rats were examined by both light and electron microscopy. On light microscopical examinations of specimens stained with Coomassie blue after the treatment with Triton X-100, the networks were detected 5 days after culture, which consisted of triangles arranged mainly in hexagonal patterns. They surrounded main cell body, looking like a headband, or were occasionally situated over nuclei, looking like a geodesic dome. Scanning electron microscopical observations after Triton treatment revealed that these structures were located underneath surface membrane. Transmission electron microscopical investigations revealed that the connecting fibers of networks consisted of microfilaments which radiated in a compact bundle from electron-dense vertices.

Actin Cytoskeleton↗
PubMed1988

Neihumicin, a new cytotoxic antibiotic from Micromonospora neihuensis. I. The producing organism, fermentation, isolation and biological properties.

A new cytotoxic and antifungal antibiotic, neihumicin, was isolated from the culture broth of a soil isolate identified as Micromonospora neihuensis Wu, sp. nov. Neihumicin shows in vitro cytotoxicity against KB tissue culture cells (ED50 0.94 micrograms/ml) as well as antifungal activity against Saccharomyces cerevisiae ATCC 9763.

Antibiotics, Antineoplastic↗
PubMed1988

Neihumicin, a new cytotoxic antibiotic from Micromonospora neihuensis. III. Structure-activity relationships.

Structure-cytotoxicity relationships studies have indicated that the C-3 and C-6 disubstituted piperazine-2,5-diones are structurally required for significant cytotoxicity, and the neihumicin-like C-3 and C-6 disubstituted unsymmetrical piperazine derivatives are, in general, more cytotoxic than the corresponding symmetrical piperazine-2,5-diones. Several synthetic analogs including 3,6-di-(2,4,5-trimethoxybenzylidene)piperazine-2,5- dione, 3,6-dibenzylidene-2-ethoxy-3,6-dihydropyrazine-5-one, 3-benzylidene-6-(m-chlorobenzylidene)-2-methoxy-3,6-dihydropyrazine++ +-5-one, have been shown to be more cytotoxic than neihumicin.

Antibiotics, Antineoplastic↗
PubMed1987

T lymphocyte recognition of acetylcholine receptor: localization of the full T cell recognition profile on the extracellular part of the alpha chain of Torpedo californica acetylcholine receptor.

A series of eighteen consecutive overlapping synthetic peptides, of uniform size and overlaps, which encompass the entire extracellular part (residues 1-210) of the Torpedo californica acetylcholine receptor alpha chain were examined in vitro for their ability to stimulate lymph node cells from acetylcholine receptor-primed C57BL/6 (H-2b), C3H/He (H-2k), SWR (H-2q) and SJL (H-2s) mice. The recognition sites (T sites) by acetylcholine receptor-primed lymph node cells from these mouse strains resided within six regions on the extracellular part of the alpha chain. Three of the regions recognized by T cells coincided with regions recognized by antibodies (i.e. B cells) and one of these three regions also coincided with an alpha-neurotoxin-binding region. It is noteworthy that, in addition to sites recognized by both T and B cells, the protein has at least two sites which are recognized exclusively by T cells and to which no detectable antibody responses are directed.

Animals↗
PubMed1987

The regions of T-cell recognition on the extracellular part of the alpha chain of Torpedo californica acetylcholine receptor.

A comprehensive synthetic approach was employed to identify the continuous regions of T-cell recognition on the alpha-chain of Torpedo californica acetylcholine receptor (AChR). Eighteen synthetic consecutive overlapping peptides, of uniform size and overlaps, that spanned the entire extracellular part (residues 1-210) of the alpha chain were examined for their in vitro stimulation of lymph node cells from AChR-primed C57BL/6 (H-2b), C3H/He (H-2k), SWR(H-2q) and SJL (H-2s) mice. The T-cell recognition sites (T sites) in the AChR-primed mouse strains resided within six regions on the extracellular part of the alpha-chain. Three of the regions recognized by T cells coincided with regions recognized by antibodies (i.e. B cells) and one of these three regions also coincided with an alpha-neurotoxin binding region. It is noteworthy that, in addition to sites recognized by both T and B cells, the protein has at least two sites which are recognized exclusively by T cells and to which no detectable antibody responses are directed.

Animals↗
PubMed1987

Genetic resistance to mammary tumorigenesis in a mouse strain with high murine mammary tumor virus expression.

Although II-TES mice release large amounts of murine mammary tumor virus (MMTV) in milk, they are resistant to mammary tumorigenesis. High mammary tumor incidence was observed in (BALB/ca X II-TES)F1 and (C57BL/6N X II-TES)F1, whereas no mammary tumors developed in BALB/ca X OZ-F)F1. Mammary tumors developed in 68% of (OZ-F X (OZ-F X II-TES)F1 and 45% of (II-TES X (OZ-F X II-TES)F1). These results suggest that the II-TES mouse carries a recessive gene for mammary tumor resistance which does not inhibit MMTV release, and two independent dominant mammary tumor promoting genes which are inhibited by the resistant gene.

Animals↗