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T Amagai

Publications and source records attributed to T Amagai.

At least 19 recordsLinked to original sources
PubMed1995

Limited development capacity of the earliest embryonic murine thymus.

Previous studies have demonstrated that murine thymus separates from the pharynx during 11.5-12 days of gestation, and that the proliferation of thymic cells starts at this age. We characterized embryonic day 12 thymus in terms of the surface phenotype of the thymus cells, the function of the lobe in supporting T cell development in organ culture, and the precursor activity of the thymus cells in a mixed culture with deoxyguanosine-treated lobes. The phenotype of the major population of embryonic day 12 thymus cells was HSA+, CD44+, c-kit+, Thy-1-, CD25-, CD4-, CD8-, TcR-, and Sca-1-. In organ culture of embryonic day 12 thymus lobes, most of the lobes did not develop well and failed to generate CD4+CD8+, CD4+CD8-, or CD4-CD8+ cells, even when embryonic day 14 thymus cells were added. However, thymus cells on embryonic day 12 contained T cell precursors that developed into mature T cells in co-culture with deoxyguanosine-treated fetal thymic lobes. The majority of the stromal cells in deoxyguanosine-treated embryonic day 14 thymus lobes expressed the surface molecules I-A and H-2D, whereas these cells in embryonic day 12 thymus lobes were negative for these surface molecules. Thus, our findings suggest that the embryonic day 12 thymus lobe contains T cell precursors, but that the undeveloped thymic stromal cells are insufficient to support full T cell development.

Animals↗
PubMed1995

Oxytocin-producing and vasopressin-producing eosinophils in the mouse spleen: immunohistochemical, immuno-electron-microscopic and in situ hybridization studies.

Oxytocin-like and vasopressin-like immunoreactive cells, and the cells expressing mRNAs for these peptides in the spleen of the C57BL/6 mouse were studied by immunohistochemistry, immuno-electron microscopy and in situ hybridization. Immunoreactive cells were distributed mainly in the splenic cord and marginal zone, whereas there were few in the lymphocyte-packed periarteriolar-lymphoid sheath, lymphoid follicle and germinal center. More numerous vasopressin-positive cells were seen in the splenic cord. The colocalization of oxytocin-like and vasopressin-like immunoreactivity in the same cells was identified by the investigation of mirror sections. By the pre-embedding immuno-electron-microscopic method using antisera against oxytocin and vasopressin, immunopositive reaction products were localized in the matrix around the specific granules, small clear vesicles and mitochondrial membrane of the eosinophils. No immunoreactivity to these peptides was found within the specific granules of the eosinophils. In situ hybridization with synthetic oligonucleotide probes labeled with 32P revealed the presence of mRNAs for oxytocin and vasopressin in the cells of the spleen, the distribution of the mRNAs for these peptides being the same as that of immunopositive cells. These observations suggest that eosinophils synthesize both oxytocin and vasopressin and store them in the matrix. Possible differences in the mechanism of synthesis and storage of these peptides between peripheral eosinophils and hypothalamic neurons are discussed.

Animals↗
PubMed1991

Interleukin-2 receptor gene expression in kidney transplant recipients treated with cyclosporin A.

We examined the effects of cyclosporin A (CsA) administered in vivo on the capacity of peripheral blood mononuclear cells (PBMC) from kidney transplant recipients to express IL-2 receptor (IL-2R) gene at the level of mRNA after mitogen stimulation in vitro. There were no differences in the percentage of IL-2R+ cells among the groups of normal individuals, azathioprine-prednisolone treated, and CsA-prednisolone-treated recipients, using FITC-labelled monoclonal anti-IL-2R antibody (anti-alpha chain): 40.3 +/- 10.1% and 62.8 +/- 11.1% of normal PBMC (n = 18), 37.0 +/- 9.3% and 61.7 +/- 5.8% of PBMC from azathioprine-prednisolone-treated recipients (n = 20), and 37.7 +/- 9.6% and 60.7 +/- 12.7% of PBMC from CsA-prednisolone-treated recipients (n = 20) expressed IL-2R after 24 h and 48 h of phytohaemagglutinin stimulation, respectively. However, in a study of Northern blotting using cDNA for IL-2R (anti-alpha chain specific), both the 3500 and 1400 bp families of IL-2R mRNA were remarkably decreased in PBMC from CsA-prednisolone-treated recipients compared with azathioprine-prednisolone-treated recipients and normal individuals. These studies demonstrated that CsA could inhibit IL-2R gene expression at the level of mRNA at physiological concentration.

Adult↗
PubMed1990

Monoclonal antibody A7 tumor localization enhancement by its F(ab')2 fragments to colon carcinoma xenografts in nude mice.

The monoclonal antibody A7 (MoAb A7), which belongs to IgG1, was digested with pepsin to yield F(ab')2 fragments. The maximum binding to the human colon cancer cell line, SW1116, was 27% with 125-I labeled whole MoAb A7 and 24% with 125-I labeled F(ab')2 fragments using an in vitro binding assay. The results showed that the binding activity of F(ab')2 to SW1116 was practically the same as that of whole MoAb A7. The preferred localization of the fragments to tumor tissue, compared with normal mouse tissue, was demonstrated in mice carrying SW1116 xenografts. The tumor:blood ratio three days after injection was 2.64:18.5 for whole MoAb A7:F(ab')2, respectively. The tissue:blood ratios for the F(ab')2 fragments showed a value of 18.5 in tumors, whereas its was a value less than 1.0 in normal organs. The tumor accumulation of F(ab')2 fragments was also dependent on the antigenic expression of each tumor among xenografts of colon carcinoma SW1116 and WiDr, and squamous cell carcinoma KB. In kinetic experiments with whole MoAb A7 and its F(ab')2 fragments, whole MoAb A7 was lost, with a half-life of 4 days, in both blood and tumors, whereas F(ab')2 fragments were rapidly lost with a half-life of 1.5 days. These results suggested that the F(ab')2 fragments were cleared from the blood faster than was whole MoAb A7.

Animals↗
PubMed1989

Immunochemical characterization of the antigen recognized by the murine monoclonal antibody A7 against human colorectal cancer.

The nature of the antigen recognized by the murine monoclonal antibody A7 (Mab A7) against human colorectal carcinoma was investigated using immunochemical and biochemical techniques. Binding activity of 125I-labeled Mab A7 was examined using various human cancer cell lines. Mab A7 gave the highly specific binding to colon cancer cell lines, SW1116 and WiDr, and gave only a very weak or no reactivity to gastric cancer cell lines, pancreas cell lines or lung cancer cell lines. SDS-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting of the extractable antigen from SW1116 showed a single band at approximately 45,000 dalton formed by 125I-labeled Mab A7. Treatment of SW1116 with sodium periodate, pronase and ficin resulted in the loss of antigenic activity. These data strongly suggest that the antigen recognized by Mab A7 is composed of glycoprotein. Competitive binding analysis to the surface of the colon cancer cell line using polyclonal anti-CEA and Mab A7 as well as immunoblotting analysis using monoclonal anti-CEA and Mab A7 suggested that the antigen recognized by Mab A7 was different from CEA. Moreover, this antigen was also found in surgical specimens of colorectal cancer patients and its molecular property was identical to the antigen extracted from SW1116.

Animals↗
PubMed1989

[Surgical treatment of esophageal stenosis with recessive dystrophic epidermolysis bullosa--esophageal dilatation using balloon catheter method].

We report the details of our treatment of 5 patients with recessive dystrophic epidermolysis bullosa (RDEB). Good results were obtained by esophageal dilatation using the balloon catheter method. Prior to the operation, we corrected the patients' nutritional status with oral supplementation of Hinex-R as well as intravenous drip infusion of Intra-lipid, based on the nutrition index obtained by body weight, serum albumin, rapid turnover proteins, and blood minimum essence. After sufficient anesthesia of the nasopharyngeal mucosa with xylocain spray, we inserted a Microvasive Rigiflex Balloon Dilator into the stenotic region while scanning the upper GI. Then we dilated gradually by barium injection. The patients' condition improved after this treatment and follow up X-ray examination revealed no recurrence of stenosis. There were several advantages to this method: 1) It was safer and could be done repeatedly. 2) It caused less stress for patients. 3) Its effectiveness appeared rapidly. We analyzed the frequency and severity of esophageal stenosis of 12 cases with EB in our department. Ten out of 12 cases complained of subjective esophageal symptoms. Esophageal stenosis was observed in all 8 cases examined by esophagogram. We concluded that this surgical procedure for esophageal stenosis was as important as digit reconstruction in the management of RDEB.

Adolescent↗
PubMed1988

Functional differentiation and repertoire diversification of T cells derived from single progenitor cells.

Functions of T cells derived from single progenitor cells were investigated. B10. Thy-1.1 recipient mice were either whole body-irradiated and marrow reconstituted or thymus-shielded, irradiated and marrow reconstituted, and limited numbers (3 x 10(3) or 6 x 10(3] of a 1:1 mixture of bone marrow cells from C57BL/6 and B6.Lyt-2.1 mice were transferred intrathymically (i.t.). Donor-type (Thy-1.2+) cells of the thymus of a small portion of recipients which expressed the phenotype of either Ly-2.2 or Ly-2.1 but not both were regarded to be a clone of T cells derived from a single progenitor cell, and such clones were assayed for polyclonal helper (Th) and polyclonal cytolytic (CTL) activities as well as alloantigen-specific proliferative (mixed lymphocyte reaction; MLR) and CTL activities. Clones taken 4 weeks after transfer (4-week-old clones) which were generated in the thymus of whole body-irradiated recipients showed polyclonal CTL but not polyclonal Th activity, whereas 4-week-old clones generated in the thymus of thymus-shielded recipients showed both polyclonal CTL and Th activities. Similarly, 4-week-old clones generated in whole body-irradiated recipients responded with CTL to alloantigens when induced in the presence of T cell growth factors but not with MLR, whereas 4-week-old clones generated in thymus-shielded recipients showed both MLR and CTL to alloantigens. Repertoire diversification of 4-week-old clones, however, was incomplete, since clones generated in whole body-irradiated recipient did not necessarily respond with CTL to all alloantigens examined, and those generated in thymus-shielded recipients did not necessarily respond with MLR to all the antigens. On the other hand, T cell clones were shown to fully mature by 7 weeks after transfer in terms of cell function as well as repertoire diversification.

Animals↗
PubMed1988

Immortalization of murine leukocytes by oncogenes. II. Phenotypic characterization of transformants immortalized by v-src or Ha-ras oncogenes: expression of B220, a B-cell lineage specific antigen.

In the course of study to obtain murine dendritic cell lines using oncogenic retroviruses, we have established several immortalized cell lines with characteristics different from those of dendritic cells. The transformants were mainly round nonadherent cells, capable of growing in soft agar, and negative for nonspecific esterase activity. Profiles of cell surface antigens were examined by indirect immunofluorescence technique. The cell lines were positive for Fc receptor (2.4G2), J11d (J11d.2), and B220 (RA3-3A1/6.1) antigens and negative (or dull positive in small percentages) for Ia (M5/144.15.2), IL-2 receptor (3C7), Thy-1 (B5-5), Mac-1 (M1/70.-15.11.5), and macrophage (F4/80) antigens. They were negative for both surface and cytoplasmic immunoglobulins. Several clones were established from these transformant cell lines and cell surface antigens were examined. Antigenic profiles of these clones were very similar to those of the parental cell lines. Some of these clones, however, seemed to increase their Ia antigen expression. The results suggest that the transformants originated from early B-lineage cells.

Animals↗
PubMed1988

[Problems and difficulties in adapting period in infants and children after massive intestinal resection].

In the period of intestinal adaptation following massive resection of intestine, patients have several difficulties and problems. This study was done in 17 survivals of 31 infants and children received massive intestinal resection (residual intestine; less than 75 cm) between 1966-1987 to define these problems and difficulties. 1) Postoperative hepatic dysfunction occurred in 11 of the 17 survivals. The relationship between relapsing frequency of hepatic dysfunction and length of remaining ileal segment suggested that the reduced ileal length may be one of the etiologic factors of the hepatic dysfunction. 2) Evaluation of serum bile acid levels suggested that the disturbance of bile acid reabsorption and its rapid turn over might still remain even after catch-up growth of these patients. 3) Abnormal levels of serum minerals (Ca, InP, Mg, Zn and Cu) were observed in 4 cases during TPN, and these abnormalities disappeared by discontinuation of parenteral nutrition and beginning of oral feeding. 4) Serum vitamin levels (Vit.A, Vit.E, 25-OH-D3, and Vit.B12) still remained in abnormal even after the patients reached school age. These results suggested that very long-term nutritional cares, especially in lipid and vitamin nutrition, are necessary for the children with massive intestinal resection.

Bile Acids and Salts↗
PubMed1988

Suppression of genetic resistance to bone marrow grafts and natural killer activity by administration of fat emulsion.

Graft rejection is one of the major obstacles to successful bone marrow transplantation (BMT). If resistance to marrow grafting could be avoided, BMT could be used widely in treatment of hematological and immunological disorders. There has been evidence that natural killer (NK) cells play a major role in genetic resistance to BMT and that macrophages are also involved in genetic resistance. Agents toxic to macrophages such as silica and carrageenan have been found to have a suppressive effect on genetic resistance to BMT. Parenteral fat emulsions are known to accumulate in macrophages and to impair various functions of macrophages and those of the reticuloendothelial system. We show here that the administration of a fat emulsion, Intralipos 20%, to recipient mice can suppress genetic resistance to bone marrow grafts and NK cell activity probably through the impairment of the macrophage function. The administration of the fat emulsion might be a new tactic in conditioning protocols for human BMT in the future.

Animals↗
PubMed1987

Dysfunction of irradiated thymus for the development of helper T cells.

The development of cytotoxic T cells and helper T cells in an intact or irradiated thymus was investigated. C57BL/6 (H-2b, Thy-1.2) mice were whole body-irradiated, or were irradiated with shielding over either the thymus or right leg and tail, and were transferred with 1.5 X 10(7) bone marrow cells from B10.Thy-1.1 mice (H-2b, Thy-1.1). At various days after reconstitution, thymus cells from the recipient mice were harvested and a peanut agglutinin low-binding population was isolated. This population was further treated with anti-Thy-1.2 plus complement to remove host-derived cells and was assayed for the frequency of cytotoxic T cell precursors (CTLp) and for the activity of helper T cells (Th). In the thymus of thymus-shielded and irradiated mice, Th activity reached normal control level by day 25, whereas CTLp frequency remained at a very low level during these days. In the thymus of whole body-irradiated mice, generation of CTLp was highly accelerated while that of Th was retarded, the period required for reconstitution being 25 days and more than 42 days for CTLp and Th, respectively. Preferential development of CTLp was also seen in right leg- and tail-shielded (L-T-shielded) and irradiated recipients. Histological observation indicated that Ia+ nonlymphoid cells were well preserved in the thymus of thymus-shielded and irradiated recipients, whereas in L-T-shielded and irradiated recipients, such cells in the medulla were markedly reduced in number. These results suggest strongly that the generation of Th but not CTLp is dependent on radiosensitive thymic component(s), and that such components may represent Ia+ cells themselves in the medulla or some microenvironment related to Ia+ cells.

Animals↗
PubMed1987

Cell surface membrane antigen present on neuroblastoma cells but not fetal neuroblasts recognized by a monoclonal antibody (KP-NAC8).

Neuroblastoma (NB) arises from primitive sympathetic neuroblasts in the adrenal gland or the sympathetic ganglion. NB in situ, sometimes observed in the adrenal glands of autopsied infants, is considered to be a premalignant lesion that may develop into NB. Little is understood about the morphological and biochemical changes that accompany this malignant progression. In this study, a unique monoclonal antibody, KP-NAC8, raised against a human NB cell line is described. This binds to NB cells but not to fetal neuroblasts. The antibody recognizes a Mr 200,000 surface protein on NB cells. KP-NAC8 binds to 15 of 17 human NB cell lines and all 26 fresh NB samples either from tumor tissues or from marrow aspirates involved with tumor. The antibody was found to cross-react with some other tumor cell lines, namely, Ewing's sarcoma (1 of 2), melanoma (1 of 4), lung cancer (3 of 3), and leukemia (2 of 14) cell lines. However, KP-NAC8 did not bind to any rhabdomyosarcoma (0 of 4), Wilms' tumor (0 of 4), retinoblastoma (0 of 2), glioma (0 of 4), and gastric cancer (0 of 2) cell lines examined. Among fetal tissues, KP-NAC8 did not react with normal neuroblasts in the adrenal glands of 5 fetuses. In a further study, the membrane phenotype of fetal adrenal neuroblasts was analyzed by a panel of 12 monoclonal antibodies including KP-NAC8. A comparison of the binding of the same panel of antibodies to fresh NB revealed that antibodies UJ13A, UJ127:11, PI153/3, anti-Thy-1, A2B5, BA-1, BA-2, HSAN1.2, and Leu-7 bound to both fetal adrenal neuroblasts and NB cells. Monoclonal antibodies OKIa-1 and J5 did not bind to either tissues. The only antibody that could distinguish fetal adrenal neuroblasts from NB cells was KP-NAC8. KP-NAC8 may, therefore, define a differentiation-related antigen that may prove helpful in understanding the biological nature of NB and NB in situ.

Adrenal Glands↗
PubMed1987

Production of a monoclonal antibody with specificity for the pellicle of Pneumocystis carinii by hybridoma.

This study reports the establishment of cloned hybridomas between mouse myeloma cells (P3-X63-Ag8, 6.5.3) and spleen cells from BALB/c mice immunized with lung homogenates of nude mice (BALB/c nu/nu) heavily infected with Pneumocystis carinii. A hybridoma subclone, designated 1E12-8, produced antibodies of an IgG1 subclass. Using indirect immunofluorescent antibody techniques, the monoclonal antibody was found to be directed toward the pellicle antigen of air-dried P. carinii both in trophozoite and cyst forms, and to recognize the P. carinii antigen not only from nude mice but also from rats. The antibody did not cross-react with other components of the infected host lung tissue and showed little cross-reactivity with fungi examined. The monoclonal antibody should be useful in the isolation and identification of corresponding antigenic substances of P. carinii and may provide a useful tool in epidemiology, taxonomy, and diagnosis of this organism.

Animals↗
PubMed1987

Specific cell surface labels in the visual centers of Xenopus laevis tadpole identified using monoclonal antibodies.

Monoclonal antibodies (MAbs) against the optic tectum of Xenopus tadpoles were generated and screened by the immunofluorescent staining of frozen sections of tadpole brains. MAb-A5 stains the 8th and 9th plexiform layers of the optic tectum, whereas MAb-B2 stains all but the eighth and ninth plexiform layers of the optic tectum. MAb-A5 antigen is also detectable in the nucleus of Belonci, the corpus geniculatum thalamicum, the pretectal area, and the basal optic nucleus, all targets of the optic nerve, but is not detectable in the optic nerve or the optic tract. On the other hand, MAb-B2 does not stain any of these visual centers, though many fibers surrounding them are stained. Eye-enucleation experiments showed that MAb-A5 antigen is expressed in the optic tectum even when it is not innervated by optic nerves. Staining of viable brains with these MAbs indicates that these antigens are cell surface molecules. Immunoadsorption followed by SDS-PAGE suggests that proteins are constituents of these antigens. The MAb-A5 antigen in the diencephalon and the mesencephalon is not detectable at stage 35/36, but is detectable at stage 39 when the optic nerves begin to innervate the optic tectum. The spatial as well as the temporal patterns of the expression of the MAb-A5 antigen suggest that this molecule may be involved in the target recognition of optic nerve fibers.

Animals↗
PubMed1987

Concanavalin A-mediated polyclonal helper assay of normal thymocytes and its use for the analysis of ontogeny.

A concanavalin A (Con A)-mediated polyclonal helper assay system was established by using the thymus cells or splenic T cells as a source of helper T cells. When splenic B cells were cocultured with thymus cells or splenic Lyt-2- T cells in the presence of an optimal dose of Con A, B Cells were polyclonally activated and differentiated into immunoglobulin-secreting cells. This Con A-mediated helper activity was completely inhibited by the addition of alpha-methyl-D-mannoside and could not be substituted by culture supernatant of Con A-stimulated thymocytes or splenic T cells. Almost all the activity of the thymus cells was carried by peanut agglutinin low binding population. Genetic restriction between T and B cells was not observed in this helper function. In ontogeny, Con A-mediated helper activity in the thymus was first detected at a few days after birth and reached the adult level at about 1 week of age. The polyclonal helper assay system developed in the present study provides a sensitive system to analyse the helper function of thymus cells and also to delineate the early phase of the differentiation of helper T cell population.

Age Factors↗
PubMed1986

Limiting dilution analysis of the stem cells for T cell lineage.

Stem cell activities of bone marrow, spleen, thymus, and fetal liver cells for T cell lineage were studied comparatively by transferring the cells from these organs through i.v. or intrathymus (i.t.) route into right leg- and tail-shielded (L-T-shielded) and 900 R-irradiated recipient mice, which were able to survive without supplying hemopoietic stem cells. Cells from B10.Thy-1.1 (H-2b, Thy-1.1) mice were serially diluted and were transferred into L-T-shielded and irradiated C57BL/6 (H-2b, Thy-1.2) mice, and 21 days later the thymus cells of recipient mice were assayed for Thy-1.1+ cells by flow cytofluorometry. The percentage of recipient mice possessing donor-type T cells was plotted against the number of cells transferred, and the stem cell activity in each cell source was expressed as the 50% positive value, the number of donor cells required for generating donor-type T cells in the thymuses of 50% of recipient mice. In i.v. transfer experiments, the activity of bone marrow cells was similar to that of fetal liver cells, and about 100 times and nearly 1000 times higher than those of spleen cells and thymus cells, respectively. In i.t. transfer experiments, the number of cells required for generating donor-type T cells was much lower than that in i.v. transfer experiments, although the ratio in 50% positive values between i.v. and i.t. transfers differed among cell sources. In i.t. transfers, the 50% positive value of bone marrow cells was five times, 400 times, and 500 times higher than that of fetal liver cells, spleen cells, and thymus cells, respectively. Our previous finding that stem cells are enriched in the spleens of mice which were whole body-irradiated and marrow-reconstituted 7 days earlier was confirmed also by the present limiting dilution assay carried out in i.v. as well as i.t. transfers.

Animals↗