Search PubMed⌕ Search

Biomedical subjects

T Yokochi

Publications and source records attributed to T Yokochi.

At least 19 recordsLinked to original sources
PubMed1992

Detection of lipopolysaccharide (LPS) and identification of its serotype by an enzyme-linked immunosorbent assay (ELISA) using poly-L-lysine.

A new solid-phase enzyme-linked immunosorbent assay (ELISA) was developed for detection of LPS and identification of its serotype with antisera. Since LPS binds poorly to polystyrene microplates, precoating with poly-L-lysine was used before coating LPS on the surface of microplates. The small amount of LPS in complex mixtures (i.e., less than 1 microgram/ml) could be detectable in ELISA. Use of poly-L-lysine with high molecular weight (MW) provided a higher sensitivity than poly-L-lysine with low MW. Precoating with polymyxin B, or poly-L-histidine was less effective in the sensitivity than precoating with poly-L-lysine, but it was still better than no precoating. The newly developed ELISA technique could be also applied for detection of anti-LPS antibodies in sera or for screening of monoclonal anti-LPS antibody.

Animals↗
PubMed1992

Novel adjuvant action of lipopolysaccharides that possess mannose homopolysaccharides as O-specific polysaccharides on immune responses to nonimmunogenic autoantigens in mice.

The adjuvant action of various lipopolysaccharides on immune responses to syngeneic tissue extract in mice was examined. Only lipopolysaccharides possessing the linear mannose homopolysaccharides as O-specific polysaccharides exhibited definite adjuvant action on immune responses to the autoantigens. The intensity of this adjuvant activity of lipopolysaccharide from Klebsiella O3 seemed to be the strongest.

Animals↗
PubMed1992

Experimental autoimmune adrenalitis: a murine model for Addison's disease.

Experimental autoimmune adrenalitis was produced in mice by immunizing 8 times or more at intervals of 30 days with syngeneic adrenal extract mixed with Klebsiella O3 lipopolysaccharide (KO3 LPS) as a potent adjuvant. The cortex regions of the adrenal glands after the 8th injection were definitely infiltrated with polymorphonuclear leukocytes (PMN). The main infiltrates in the lesions after the 9th injection were replaced by mononuclear cells, such as small lymphocytes and macrophages, and further by fibrous connective tissues. There were no histological changes in the medullary regions. The repeated immunization developed the delayed type hypersensitivity to adrenal extract and production of anti-adrenocortical autoantibody in those immunized mice. Moreover, the adrenalitis could be produced in normal mice by transfer of spleen cells from hyperimmunized mice, suggesting the critical role of the cell-mediated immunity. This experimental model might be useful to study immunological phenomena in the pathogenesis of Addison's disease.

Addison Disease↗
PubMed1992

Establishment of hybridoma cells with natural killer(NK)-like activity against syngenic tumor cells.

The 4D1D4 hybridoma cells were derived from the fusion of spleen cells from BALB/c nude mice with NS-1 mouse myeloma cells. The surface phenotypes of 4D1D4 hybridoma cells were Thy-1.2+, L3T4 (CD4)-, Lyt-2 (CD8)-, Asialo GM1+ and p-55 interleukin-2 (IL-2) receptor (CD25)-. This phenotypic pattern was consistent with the surface phenotype of NK cells. The 4D1D4 cells showed the definite killer activity against a syngenic tumor cell line, RL male-1, but not against an allogenic YAC-1 line. The killer activity of the 4D1D4 cells was not affected by the addition of exogenous IL-2. It was, therefore, suggested that 4D1D4 cells might be representative of resting NK cells with expression of no functional IL-2 receptors. The hybridoma technology might be useful for establishment of the cloned NK cells.

Animals↗
PubMed1991

A new mouse model for autoimmune orchitis.

Experimental autoimmune orchitis (EAO) was induced in SMA mice (H-2nondefined) by repeated injection at intervals of 30 days of syngeneic testis homogenate (TH) together with Klebsiella O3 lipopolysaccharide (KO3 LPS) as a potent adjuvant. EAO was not induced by repeated injection of TH alone or KO3 LPS alone. At 10 days after the secondary injection of TH + KO3 LPS, there was marked infiltration with neutrophils in the seminiferous tubules and in the interstitium of the testis accompanied by destruction of the architecture of the seminiferous tubules and hypospermatogenesis. At 20 days after the secondary injection, infiltration with neutrophils in these areas had been replaced mostly by mononuclear cells (lymphocytes, plasma cells, and macrophages). Histopathological changes of the testes became severer by further injections until the 10th injection. The EAO lesions in the terminal stage were characterized by complete destruction of the tubular architecture of the testis, fibrosis, and aspermatogenesis. Lesions in the terminal stage were not restored at all. Spermagglutinating antibody titers in the serum increased and delayed-type hypersensitivity against TH estimated by footpad swelling developed in mice injected repeatedly with TH + KO3 LPS. Using immunofluorescence, antibodies against acrosomal components and tail components of the spermatozoa were detected in serum of these mice.

Animals↗
PubMed1991

Molecular cloning of the gene coding for the human T cell differentiation antigen CD7.

The CD7 molecule is a differentiation antigen found on the surface of T lymphocytes and also on a very minor fraction of acute nonlymphocytic leukemia (ANLL). To study the genomic structure of the CD7 gene, two clones (SY4 and SY22) were isolated by screening a genomic library with a CD7 cDNA probe. Restriction mapping of these two phage clones showed that both overlapped each other, covering a total length of 23 kilobases (kb). Transfection of mouse L cells demonstrated that SY22 contains the gene expressing the CD7 antigen reactive with monoclonal CD7 antibody (Tp40), while SY4 does not. Subcloning of a 10.5 kb fragment from a 14.4 kb insert of SY22 contained the structural gene for the CD7 antigen. Detailed restriction mapping and partial sequence analysis revealed the CD7 gene to consist of four exons. By RNase protection assay, multiple initiation sites -122 base pairs (bp) to -38 bp from ATG translation initiation site were demonstrated. The promoter region had high G + C content and contained two SP1 binding sites (CCGCCC) and an AP2 binding site (CCCCAGGC), but lacked CAAT and TATA motifs.

Amino Acid Sequence↗
PubMed1991

A new sensitive and rapid automated fluorometric assay for detection of natural killer activity using carboxyfluorescein diacetate.

An automated fluorometric assay using carboxyfluorescein diacetate (CFDA) has been applied for the sensitive and rapid detection of natural killer (NK) activity. The lysis of target cells by NK cells was quantified by measuring the amount of CFDA released into the supernatant of culture wells with the aid of an automated microfluorometer. Both sensitivity and specificity of the presented method were higher than the 51Cr release assay. Moreover, the detection of human NK activity against K562 target cells required only 2 hrs, compared to 4 hrs in the standard 51Cr release assay.

Animals↗
PubMed1991

Novel cell surface antigens expressed on mouse alveolar macrophages.

Two new cell surface antigens expressed on mouse alveolar macrophages were defined by rat monoclonal antibodies. One marker, AVM-1, was detected on mouse alveolar macrophages, but it was undetectable on resident peritoneal cells, thioglycollate medium-induced peritoneal cells, and splenic macrophages. Splenic lymphocytes, thymocytes and bone marrow cells were also AVM-1 negative. Anti-AVM-1 monoclonal antibody immunoprecipitated a single polypeptide with a molecular weight of 200,000. Of particular interest was the finding that the anti-AVM-1 antibody could inhibit the formation of EA and EAC rosette on macrophage line cells. A second antigen (AVM-2) was also present on alveolar macrophages, and its molecular weight was 38,000.

Animals↗
PubMed1991

Characterization of the individual and cross-reactive antigens involved in the anti-tumor immunity induced by use of an H-2K-erbB recombinant gene transfectant.

The specificities of the antisera raised in the CDF1 mice that had been immunized with the P1.HTR tumor cells xenogenized by transfection with recombinant H-2Kb-erbB gene were studied. The antisera cross-reacted with a broad range of tumor cell lines maintained either in vitro or in vivo in an immunofluorescence assay. However, they did not react at all with syngeneic normal tissue cells from thymus, spleen, bone marrow and fetal liver. Even though antigens related to the murine leukemia virus and murine mammary tumor virus (MuMTV) were demonstrated in many of the tumor cell lines tested with specific antibodies, these antigens did not seem to be primarily involved in the anti-P1.HTR antibody activity. The 74 kDa molecule, which was precipitated by the anti-P1.HTR anti-serum from the surface radiolabeled cell extract of P1.HTR tumor and was discriminated from the 70 kDa molecule precipitated by the anti-MuMTV serum, was widely distributed among various tumor cell lines tested, but was absent in normal tissue cells. In contrast to the extensive cross-reaction by the antibody, the cytotoxic T lymphocyte generated in the P1.HTR immune mice were shown to be specific to the P1.HTR tumor, and the 98 kDa molecule was precipitated by the anti-P1.HTR serum from the P1.HTR tumor but not from other tumors tested. It is suggested from these results that the 98 kDa molecule is a candidate for an individual tumor-specific transplantation antigen, and is immunodominant for inducing cytotoxic T lymphocytes to coexisting intrinsic retroviral antigens and other serologically cross-reactive tumor antigens.

Animals↗
PubMed1991

Histological and functional changes in the thyroid glands of mice implanted with hybridomas secreting monoclonal autoantibody against mouse thyroglobulin.

Mouse hybridoma cells secreting monoclonal antibody (mAb) against mouse thyroglobulin were established. The implantation of the hybridomas succeeded to induce high titers of circulating mAb against thyroglobulin in sera of mice. By using the implantation of the hybridomas in mice, the effect of autoantibody on the thyroid glands was studied histologically and functionally. In these mice the thyroid follicles were significantly swollen and warped, whereas there was no infiltration of inflammatory cells. The 125I-uptake in their thyroid glands was markedly decreased. There were no functional changes in control mice implanted with non-secreting P3U1 partner cells. Therefore, it was suggested that high titers of anti-thyroglobulin autoantibody could definitely cause the histological and functional damages in the thyroid glands.

Animals↗
PubMed1990

Strong interaction of lipopolysaccharides possessing the mannose homopolysaccharides with complement and its relation to adjuvant action.

LPS from Klebsiella pneumoniae O3 (KO3 LPS) exhibited an extremely high anticomplementary activity by the hemolysis assay using human sera. The free lipid A isolated from KO3 LPS by acid hydrolysis and R form LPS from a mutant lacking the O-specific polysaccharide portion possessed lower anticomplementary activity, and the O-specific polysaccharide fraction isolated from KO3 LPS alone did not activate the C system. It was suggested that the O-specific polysaccharide moiety enhanced the C activation by the lipid A portion. This was also supported by the finding that modification of the O-specific polysaccharide moiety with Con A or tyramine decreased anticomplementary activity of KO3 LPS, and that the other LPS preparations possessing the mannose homopolysaccharides as the O-specific polysaccharide portions such as KO3 LPS, such as LPS from Klebsiella O5, Escherichia coli O8 and O9, exhibited a high anticomplementary activity. KO3 LPS could activate the C system in either the classical or the alternative pathway, whereas the lipid A or R form LPS activated the classical pathway alone. The intensity of anticomplementary activity of LPS was parallel to that of their adjuvant action on antibody response to deaggregated BSA. The role of the anticomplementary activity in the expression of the adjuvant action of LPS is discussed.

Adjuvants, Immunologic↗
PubMed1990

Inhibitory effects of mold oil including gamma-linolenate on platelet thrombus formation in mesenteric microvessels of the rat.

Diet including mold oil from a lipid accumulative fungus, containing gamma-linolenic acid, showed an inhibitory effect on thrombus formation in the microvessels of rats by the light/dye method of the authors. Male Wistar rats were fed for 3 to 4 weeks with two series of experimental diets and were examined for thrombus formation. The thrombus formation times to totally occlude, ts, were 347 sec for (mold + soybean)-oil and 236 sec for (palm + soybean)-oil in the first series of diets and 1288 sec for mold oil, 538 sec for olive oil and 575 sec for safflower oil in the second series of diets. Fatty acid composition of plasma, erythrocyte and liver lipids showed an increase in arachidonate content with the diet including the mold oil. Higher arachidonate content seem favorable in inhibiting thrombus formation with increasing PGI2 formation. In terms of the level of lipid hydroperoxides, indicated as a desaturation index of constituent fatty acids, the higher desaturation index with safflower oil gave shorter ts, which suggested some oxygen derived free radicals from polyunsaturated fatty acids were involved in the mechanism of thrombogenesis study by this method.

Animals↗
PubMed1990

Differential response of B cells in the lymph node and the spleen to bacterial lipopolysaccharide.

In vivo polyclonal activation of B cells in the lymph nodes and the spleens of mice injected with bacterial lipopolysaccharide (LPS) was compared. The peak of anti-trinitrophenylated sheep red blood cells plaque-forming cell (PFC) response in the lymph node was reached 6-8 days after the injection of LPS while that in the spleen was reached at 2 days. The maximal increase in the total number of Ig-producing cells in the lymph node also occurred at the later stage. These differences in time courses of polyclonal activation of B cells between the lymph node and the spleen were not due to the absence of B cells in the lymph node, migration of PFC from the spleen to the lymph node, or qualitative differences of B cells. This phenomenon was dependent on the environmental difference between the lymph node and the spleen, because B cells from the lymph node could respond to LPS rapidly in the spleen. Further, the polyclonal activation of B cells was accelerated in the lymph nodes of mice receiving prior injection of LPS. In in vitro cultures of lymph node cells of those mice, a significant amount of interleukin-1 could be detected by stimulation of LPS. It was possible that the delayed activation of B cells in the lymph node was due to the time lag necessary for construction of the environmental condition suitable for activation of B cells, whereas in the spleen this condition can be provided without delay.

Animals↗
PubMed1990

Production of interleukin-2 by YAC-1 cells stimulated with interleukin-1 and its augmentation of the natural killer activity.

The production of interleukin-2 (IL-2) by YAC-1 cells stimulated with interleukin-1 (IL-1) was examined in the in vitro culture system. The IL-2 activity was detectable in the culture supernatant of YAC-1 cells stimulated with either a mouse IL-1 preparation or human purified IL-1. This activity could be detected 1 h after stimulation with IL-1. The addition of monoclonal antibody reactive with mouse IL-2 receptor completely blocked the IL-2 activity in the culture supernatant of IL-1-stimulated YAC-1 cells. Further, the culture supernatant of IL-1-stimulated YAC-1 cells augmented the NK activity in mouse spleen cells. The role of the IL-2 activity in the culture supernatant of IL-1-stimulated YAC-1 cells on augmentation of the NK activity is discussed.

Animals↗
PubMed1990

Aerosol vaccination with a sendai virus temperature-sensitive mutant (HVJ-pB) derived from persistently infected cells.

Experimental infections of mice with a Sendai virus temperature-sensitive (ts) mutant (HVJ-pB) were studied. Infection with the ts mutant induced the priming effect of interferon production and both humoral and cellular immune responses, although the ts mutant virus neither multiplied satisfactorily in the respiratory tracts of mice nor caused appreciable histopathologic lesions. Inoculation with the ts mutant protected mice from subsequent challenge with a parental wild-type virus. The efficacy of this protection began as little as 1 day after vaccination and continued for at least 12 weeks. It is suggested that serum antibodies were efficacious in the nasal turbinates, while specific immune spleen cells act more protectively in the lungs.

Aerosols↗
PubMed1990

Titer and specificity of autoantibody to beta 2-microglobulin in sera from patients with rheumatic disease.

Sera from patients with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and mixed connective tissue disease (MCTD) possessed higher titer of antibody to human beta 2-microglobulin (beta 2m) than those from healthy controls and patients with Behçet's disease in the enzyme-linked immunosorbent assay. It was also confirmed by the immunoprecipitation method. Anti-beta 2m antibody in sera from those patients immunoprecipitated free beta 2m but not beta 2m in association with major histocompatibility complex class I antigen heavy chain. It was suggested that anti-beta 2m antibody in sera from either patients or healthy controls might be directed mainly against free beta 2m. The relationship between the anti-beta 2m antibody and anti-lymphocytotoxic antibody found in those patients is discussed.

Adult↗
PubMed1990

Demonstration of lipid A-binding proteins on murine lymphoma cells using R-mutant gram-negative bacteria as a detector.

Some R-mutant Escherichia coli and Salmonella heavily adhered to murine lymphoma cells of B cell and T cell lineages. This adhesion was primarily mediated by membrane-localized proteins on tumor cells, which bind the polymyxin B-reactive hydrophilic structure of lipis A on bacteria. SDS-PAGE analysis of tumor cell membranes showed that proteins or glycoproteins of MW = around 45Kd, 25-35Kd and around 15Kd preferentially bind lipid A. Various lymphoma cell lines binding the bacteria at different levels possessed lipid A-binding proteins of slightly different compositions. We conclude that lymphoma cells carry not a single but a group of lipid A-binding proteins in their membranes.

Animals↗