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Biomedical subjects

T O Yoshida

Publications and source records attributed to T O Yoshida.

At least 37 records · Page 2Linked to original sources
PubMed1992

A rapid and sensitive method for HLA-DRB1 typing by acridinium-ester-labeled DNA probes.

A rapid and accurate detection of HLA class II antigen is essential for transplantation and for the understanding of disease susceptibility. Recent molecular genetic studies have revealed that the number of class II loci and the number of alleles at these loci are greater than had been previously detected. It is, therefore, of great importance to detect these extensive polymorphisms. A great deal of effort has been made on identification of individual HLA class II specificities at the DNA level, called "DNA typing." What seems to be lacking, however, is handling simplicity. Here we accomplished a simple method for HLA-DRB1 typing based on hybridization of acridinium-ester (AE)-labeled DNA probes to amplified DNA. This method is called hybridization protection assay (HPA). By using 13 AE-labeled probes, 20 homozygous B-cell lines and leukocytes from 80 healthy individuals were typed by HPA. The results were completely consistent with those obtained by polymerase chain reaction--restriction fragment length polymorphism. This method is suitable for mass screening because of its procedural simplicity and swiftness.

Acridines↗
PubMed1992

[The signal transduction mechanism responsible for interferon-gamma-inducible indoleamine 2,3-dioxygenase (IDO) gene expression in T98G cells].

The interferon (IFN)-gamma-induced indoleamine 2,3-dioxygenase (IDO) is implicated in the inhibition of intracellular pathogens, e.g. Chlamydia psittaci and Toxoplasma gondii. The intracellular signaling molecules responsible for the induction of IDO gene expression were investigated by the quantitative polymerase chain reaction. The gene expression was inhibited by a tyrosine kinase inhibitor, genistein. Being consistent with this, IFN-gamma induced increased tyrosine phosphorylation and this was inhibited by genistein. The transcription of IDO gene was not inhibited by protein kinase C (PKC) inhibitors, H-7 and staurosporine, or a calmodulin inhibitor, W-7. Irrelevance of PKC in IDO gene expression was supported by the failure of PMA or PMA + A23187 to induce IDO gene expression. These results all suggest that the tyrosine phosphorylation is a critical event in IFN-gamma-inducible IDO gene expression and PKC is not involved in the gene expression.

Gene Expression Regulation, Enzymologic↗
PubMed1991

[Antibody-producing ability of mononuclear cells from human tonsils: a consideration for immunological pathogenesis and operative indication of recurrent tonsillitis].

Antibody-production of mononuclear cells from human tonsils was examined by enzyme-linked immunosorbent assays in the culture system following polyclonal stimulations with pokeweed mitogen. The results were summarized and discussed as follows; 1) Age-related changes were not observed. 2) Antibody-producing ability in the intermittent phase of recurrent tonsillitis was significantly impaired. 3) Antibody-production in the recrudescent phase of recurrent tonsillitis was increased and might be reactivated probably by stimuli of the recent infection in vivo. 4) It was suggested that the recurrent tonsillitis was due to the low antibody-production ability of tonsillar mononuclear cells. 5) These results gave an immunological basis on the operative indication of recurrent tonsillitis.

Adolescent↗
PubMed1990

Regulation of HLA class II molecule expressions by IFN-gamma. The signal transduction mechanism in glioblastoma cell lines.

We examined the signal transduction mechanism responsible for the IFN-gamma-induced HLA class II molecule expressions on glioblastoma cell lines, T98G and A172. A series of experiments demonstrated that the activation of protein kinase C (PKC) is involved in the DR and DP molecule expressions on T98G cells. In addition to the activation of PKC, calcium influx appeared to be involved in the DR and DP molecule expressions on T98G. Northern blot analyses with actinomycin D or cycloheximide revealed that these second messengers induce the transcription of DRA and B and DPA and B genes without de novo protein synthesis. Furthermore, we examined the region of the DPB gene that is responsible for IFN-gamma-induced gene transcription by gene transfer of a series of 5' and 3' deletion mutants in which the upstream region of the DPB was linked to a reporter gene, chloramphenicol acetyltransferase. By using these deletion mutants, it appeared that the region between -152 and -126 bp contains a critical IFN-gamma-responsive element. Taken together, these results suggest that IFN-gamma activates PKC and stimulates calcium influx, resulting in the induction of transcription of DRA and B and DPA and B genes without de novo protein synthesis. In DPB gene, we speculate that preexiting protein(s) phosphorylated by PKC in the presence of Ca2+ might directly bind or indirectly interact with the region between -152 and -126 bp of the upstream sequence, leading to the induction of the transcription (possibly in concert with other nuclear protein(s) bound to the promoter sequences).

Biological Transport↗
PubMed1990

Organ-specific and systemic autoimmune diseases originate from defects in hematopoietic stem cells.

Transplantation of bone marrow cells from nonobese diabetic (NOD) mice, a model for type 1 diabetes mellitus, to C3H/HeN mice, which express I-E alpha molecules and have aspartic acid at residue 57 of the I-A beta chain, induced insulitis followed by overt diabetes in the recipient C3H/HeN mice more than 40 weeks after bone marrow transplantation. When cyclosporin A, which perturbs T-cell functions, was injected intraperitoneally into [NOD----C3H/HeN] chimeric mice daily for 1 month, the chimeric mice developed insulitis and overt diabetes within 20 weeks following bone marrow transplantation. Transplantation of bone marrow cells from (NZW x BXSB)F1 mice, which develop lupus nephritis, myocardial infarction, and idiopathic thrombocytopenic purpura, into C3H/HeN or C57BL/6J mice induced in the recipient strains both lupus nephritis and idiopathic thrombocytopenic purpura more than 3 months after transplantation. Transplantation of a stem-cell-enriched population from (NZW x BXSB)F1 mice into normal mice also induced autoimmune disease in the recipients. These results indicate that both systemic autoimmune disease and organ-specific autoimmune disease originate from defects that reside within the stem cells; the thymus and environmental factors such as sex hormones appear to act only as accelerating factors.

Animals↗
PubMed1990

The unique nucleotide sequence of the A beta gene in the NOD mouse is shared with its nondiabetic sister strains, the ILI and the CTS mouse.

It is generally held that one of the recessive genes controlling diabetes in the NOD mouse is linked to the major histocompatibility complex (MHC). Unique substitution of Asp57 with Ser in the A beta chain is considered to make the A beta gene the MHC-linked susceptibility gene. We therefore analysed the nucleotide sequences of the A beta second exon in ILI, CTS, and NON mice, which are nondiabetic inbred strains but are derived from the same Jcl-ICR mice as the NOD mouse. The DNA sequence analyses revealed that the A beta second exon sequences in the ILI and CTS mice, but not in the NON mouse, are identical to that of the NOD mouse. Possible roles of Ser57 of the A beta chain in the nondiabetic sister strains are discussed.

Amino Acid Sequence↗
PubMed1989

Restriction fragment length polymorphism analysis of major histocompatibility complex genes in the non-obese diabetic mouse strain and its non-diabetic sister strains.

It has been suggested that one of the recessive genes controlling diabetes in non-obese diabetic mice is linked to the major histocompatibility complex. We, therefore, performed restriction fragment length polymorphism studies of major histocompatibility complex genes (class I, II, and III) in non-obese diabetic mice in comparison with those of their non-diabetic sister strains, non-obese non-diabetic, cataract, and ILI mice which were derived from the same Jcl-ICR mice as the non-obese diabetic mouse was. When class II and III probes and a minimum of four restriction enzymes were used, class II and III genes of non-obese diabetic mice were indistinguishable from those of cataract and ILI mice but totally different from those of non-obese non-diabetic mice. The studies also indicated that A beta, E beta, and C4-Slp genes of non-obese diabetic, cataract, and ILI mice, and A alpha, A beta, E beta and C4-Slp genes of non-obese non-diabetic mice are different from those of BALB/c and C57BL/6 mice, respectively. While non-obese non-diabetic mice expressed the E alpha gene, non-obese diabetic, cataract, and ILI mice appeared to carry a deletion in the 5' end of the E alpha gene resulting in failure to transcribe the E alpha gene. When class I probe was used, cataract mice showed very different band patterns from those of the other ICR-derived mice. It is suggested that non-obese diabetic, non-obese non-diabetic, and ILI mice contain only a single class I D region gene.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

The tumor rejection antigen separated from Rous sarcoma virus-induced murine fibrosarcoma exhibits a molecular weight of approximately 60 kD but differs from functional pp60src.

The tumor antigen capable of inducing tumor resistance (tumor rejection antigen; TRA) was obtained in a solubilized form by sodium dodecyl sulfate (SDS) extraction of plasma membrane fraction from Rous sarcoma virus (RSV)-induced CSA1M fibrosarcoma cells (BALB/c origin). Analyses by Sephacryl S-300 gel filtration and SDS-polyacrylamide gel electrophoresis revealed that TRA activity was recovered in the fraction with a molecular weight of approximately 60 kD. Unfractionated crude SDS-solubilized preparation contained gp70 as detected by rabbit anti-gp70 antiserum, whereas such reactivity was lost in the fraction exhibiting the molecular weight of about 60 kD. Since this fraction retained pp60src activity, the relation of TRA to pp60src was further investigated. pp60v-src was also obtained from the lysate of v-src-expressing yeast transformant. Immunization of BALB/c mice with such pp60v-src-containing lysate failed to induce any significant tumor protection. The above 60 kD fraction of CSA1M solubilized antigens was allowed to bind to Sepharose beads coupled with anti-pp60src monoclonal antibody and separated into the bead-bound and bead-unbound fractions. The bead-bound fraction that was recovered from pp60src-binding beads (pp60src-positive fraction) did not exhibit the TRA activity. In contrast, immunization with the fraction depleted of pp60src activity (bead-unbound fraction) resulted in potent tumor protection. These results indicate that the solubilized membranous component(s) of CSA1M with a molecular weight of approximately 60 kD, which is distinct from functional pp60src, functions as the TRA against RSV-induced CSA1M tumor cells.

Animals↗
PubMed1988

Mechanism of target cell lysis by cytotoxic T lymphocytes (CTL) employing RSV-induced H-2 congenic and recombinant mouse tumor cells: demonstration of soluble mediators released from H-2-restricted CTL clones.

The secretion and the specificity of cytotoxic mediators from H-2-restricted cytotoxic T lymphocytes (CTL) were examined using non-virus-producing target tumor cells induced by the Schmidt-Ruppin strain of Rous sarcoma virus (SR-RSV) in B10 congenic and recombinant mice. By using rat concanavalin A supernatant, two H-2-restricted CTL clones were established from cytotoxic effector cells of B10.A(5R) mice primed with SR-RSV-induced syngeneic tumor Cell-free supernatants from the H-2-restricted CTL clones cocultured with syngeneic tumor cells had selectively high cytotoxic activity for syngeneic and H-2-compatible tumor cells, but not for H-2-incompatible tumor cells. YAC-1 cells, and B10.A(5R) blasts as defined in the 5-hr 51Cr-release assay. The cytotoxic activity was detected in the cell-free supernatants from the CTL clones cocultured with the CTL-sensitive syngeneic and H-2-compatible tumor cells, but not with the CTL-insensitive tumor cells and YAC-1 cells. The cytotoxic activity of the cell-free supernatant could be adsorbed by the syngeneic tumor cells, but not by YAC-1 and L(s) cells. Thus, the H-2-restricted CTL clones against SR-RSV-induced tumor cells were capable of releasing cytotoxic mediators by coculturing with syngeneic or H-2-compatible tumor cells, and the cytotoxic mediators showed a certain H-2-restricted manner in killing the target cells. These results suggest that the lysis of RSV-induced tumor cells by H-2-restricted CTL can at least in part be mediated by cytotoxic factors.

Adsorption↗
PubMed1988

Calcium influx and the Ca2+-calmodulin complex are involved in interferon-gamma-induced expression of HLA class II molecules on HL-60 cells.

Interferon gamma (IFN-gamma) induces HLA-DR and -DQ molecules and causes an accumulation of transcripts in HL-60 cells. Experiments were, therefore, designed to investigate the intracellular signaling molecules regulating the appearance of HLA class II molecules. The expression of HLA class II (DR and DQ) molecules induced by IFN-gamma was blocked by a calmodulin antagonist, W7, but not by a protein kinase C inhibitor, H7. Furthermore, a direct activator of protein kinase C, phorbol 12-myristate 13-acetate, was unable to induce HLA class II (DR) molecule expression. These results suggest that IFN-gamma induces HLA class II molecules on HL-60 cells by way of a calcium-calmodulin pathway and not by way of a protein kinase C pathway. Calmodulin is activated by a transient rise in the cytosolic free calcium. In fact, IFN-gamma evoked a calcium influx into HL-60 cells, whereas depletion of Ca2+ from culture medium resulted in a failure of IFN-gamma to induce DR expression. Furthermore, the calcium ionophore A23187 by itself induced DR molecule expression. These results suggest that IFN-gamma stimulates calcium influx by a so-called receptor-mediated calcium channel and activates the calmodulin branch of the calcium messenger system, resulting in the induction of DR molecules on the surface of HL-60 cells.

Calcimycin↗
PubMed1987

Regulation of HLA class II antigen expression: intracellular signaling molecules responsible for the regulation by IFN-gamma and cross-linking of Fc receptors in HL-60 cells.

The cross-linking of Fc receptors (FcR) on HL-60 cells inhibited the ability of recombinant IFN-gamma to induce HLA class II antigens. This appeared to be correlated with intracellular mRNA level. HL-60 lacked detectable HLA class II mRNA. IFN-gamma led to appearance of these transcripts, which were canceled by the cross-linking of FcR. Therefore, experiments were designed to investigate the intracellular signaling molecules regulating the appearance of HLA class II molecules or transcripts. The expression of HLA class II antigen induced by IFN-gamma was blocked by a calmodulin antagonist, W-7, but not by a protein kinase C (PKC) inhibitor, H-7. Furthermore, a direct activator of PKC, phorbol myristate acetate, was not able to induce the HLA class II antigen expression. These results suggest that IFN-gamma induces HLA class II antigens on HL-60 cells via a calcium-calmodulin pathway and not via a PKC pathway. Calmodulin is activated by a transient rise in the cytosolic free calcium. In fact, the measurement of calcium influx into HL-60 cells showed that a remarkable and time-dependent calcium accumulation was caused by IFN-gamma, and that depletion of Ca2+ from culture medium resulted in failure of IFN-gamma to induce class II antigen expression. Furthermore, calcium ionophore, A23187, by itself induced HLA class II antigen expression. These results suggest that IFN-gamma stimulates calcium influx and activates the calmodulin branch of the calcium messenger system, resulting in the induction of class II antigen expression on HL-60 cells. On the other hand, cross-linking of FcR elicited the accumulation of intracellular cAMP, which appeared to suppress the IFN-gamma-induced calcium influx, resulting in annulling HLA class II antigen-inducing activity of IFN-gamma. These intracellular events of HL-60 regulate the expression of HLA class II transcripts and molecules.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1987

Recognition of Rous sarcoma virus-induced tumor antigens by cytotoxic T lymphocytes (CTL): studies on specificity of killing by CTL employing H-2 congenic and recombinant mouse tumor cells.

The specificities of cytotoxic T lymphocytes (CTL) were studied for the analysis of CTL against tumor-specific cell surface antigen(s) (TSSA) of non-virus-producing tumor cells induced by the Schmidt-Ruppin strain of Rous sarcoma virus (SR-RSV) in B10 congenic and recombinant mice. Eight CTL clones were established from immune spleen cells of B10.A(5R) mice. These clones demonstrated six patterns of cytotoxic reactivity in vitro: Two clones showed H-2 restriction in tumor cell lysis. Two other clones had the capacity to lyse syngeneic, H-2K-compatible B10 and H-2-incompatible B10.A(4R) tumor cells, but not YAC-1 cells. One clone had cytotoxic activity against syngeneic, H-2D-compatible B10.D2 tumor cells and YAC-1 cells, but not against H-2-incompatible tumor cells. One clone had cytotoxic activity against syngeneic and YAC-1 tumor cells, but not against either H-2-compatible or H-2-incompatible tumor cells. One clone had lytic activity to syngeneic, H-2-compatible, H-2-incompatible, and YAC-1 tumor cells. Another clone killed H-2-incompatible B10.A(4R) tumor and YAC-1 cells, but not syngeneic or H-2-compatible tumor cells. All these clones strongly expressed surface Thy-1.2 antigens, whereas the expression of Lyt-1.2 and Lyt-2.2 antigens was different from clone to clone. These results demonstrate heterogeneity of both lytic specificity and phenotype of CTL against RSV-induced mouse tumor cells, suggesting the existence of multiple antigenic sites on the RSV TSSA recognized by CTL populations.

Animals↗
PubMed1987

The role of transfected HLA-DQ genes in the mixed lymphocyte reaction-like condition.

DR gene products are commonly thought to be involved in the induction of the mixed lymphocyte reaction (MLR). However, very little is known about the role of HLA-DQ antigens in the MLR. To address this question, we introduced DQ alpha and beta chain genes into mouse L cells, a human T-cell line, and a human premonocytoid cell line using a liposome-mediated transfer technique. The DQ alpha and DQ beta genomic clones were isolated from a DR2 DQw1 and a DR3 DQw2 phage library, respectively. The pSV2-Neo gene was introduced as a selection marker with both DQ alpha and DQ beta. The resultant transfected cells were able to bind several HLA class II monoclonal antibodies. In addition, these cells were found to be efficient in stimulating peripheral blood lymphocyte proliferation under MLR-like conditions, implying a role for HLA-DQ molecules in HLA-D typing differences.

Animals↗
PubMed1987

Low molecular weight factors displaying augmenting activity for human antibody production in vitro.

Dialyzable low molecular weight antibody-augmenting factors (LMAAF) were found in the culture supernatant of human tonsillar lymphocytes which were not stimulated by antigen and/or mitogen in vitro. Phagocyte-depleted nylon wool-adherent lymphocytes (M-Ny+ cells) were responsible for the release of the LMAAF. Marbrook's culture system was adopted to assay for the LMAAF. The M-Ny+ cells, which were cultured without antigen and/or without mitogen in the reservoir of Marbrook's diffusion culture vessel, released the LMAAF, which diffused across a dialysis membrane and significantly augmented the pokeweed mitogen (PWM)-induced plaque-forming cell (PFC) response of phagocyte-depleted lymphocytes (M-cells) cultured in the inner vessel. Phagocyte-depleted nylon wool-passed lymphocytes (M-Ny- cells) cultured in the reservoir could not augment the PWM-induced PFC response of the M- cells cultured in the inner vessel. The exuded fluid, which was the dialysate of the culture supernatant of the M-Ny+ cells ultrafiltrated with dialysis tubing, also enhanced the PFC response of M- cells cultured in 24-well multi plates. The exuded fluid also augmented the total IgM and IgG production of human tonsillar and peripheral blood lymphocytes measured by enzyme-linked immunosorbent assay (ELISA) systems. Gel filtration chromatography on Sephadex G-25 Superfine column showed that the LMAAF activity was demonstrated in the fractions corresponding to a molecular weight (m.w.) of 362 to 1,355 and a m.w. of 3,560 to 5,700, with a peak activity at about 4,500 dalton. The LMAAF were inactivated by treatment with proteinase K, but not by trypsin, alpha-chymotrypsin, RNase, and DNase, and were stable when treated at 56 C for 60 min. The dialysates of culture supernatants from two out of seven Epstein-Barr virus (EBV)-transformed M-Ny+ cell lines showed LMAAF-like activity. These results indicate that phagocyte-depleted nylon wool-adherent lymphocytes, possibly B cells, release low molecular weight factors displaying augmenting activity for human antibody production in vitro.

Antibody Formation↗
PubMed1987

The interaction of recombinant IL-2 with human resting lymphocytes: blocking effects of monoclonal antibodies to IL-2 receptors.

Several lines of evidence suggest that subsets of resting lymphocytes naturally express interleukin-2 receptors (IL-2.R). Recombinant IL-2 (rIL-2) induced the enhancement of natural killer (NK) activity, the generation of activated killer (AK) cells, the proliferation of resting lymphocytes, and the production of interferon-gamma (IFN-gamma) in lymphocyte cultures. The subsets of lymphocytes mediating these responses appeared to be heterogeneous, but reside predominantly in nylon wool-passed non-T, non-B cells ("null cells" or T3- cells); in response to rIL-2, only Leu 11+T3- cells showed enhanced NK activity, and both Leu 11+T3- and Leu11-T3- cells showed predominantly AK activity, proliferation and production of IFN-gamma. These findings suggest that the T3- fraction (null cell fraction) contains predominantly cells expressing IL-2.R at the resting state. Unlike the case with activated T cells, however, none of these responses was blocked by any of three monoclonal antibodies to IL-2.R, including anti-Tac antibody at any dilution. These results indicate that IL-2.R on the resting T3- cells possess unique biological features compared to those on activated T or B cells. A most likely explanation is that T3- cells possess higher affinity IL-2.R than activated T or B cells. Other possibilities are also discussed.

Antibodies, Monoclonal↗