Biomedical subjects

M Utsuyama

Publications and source records attributed to M Utsuyama.

At least 37 records · Page 2Linked to original sources

PubMed1997

Effect of restraint stress on immune system and experimental B16 melanoma metastasis in aged mice.

An overnight restraint stress was given to young and old mice and its effect was examined in terms of the number and function of T cells and natural killer (NK) cells in spleen and patterns of lung metastasis of B16 melanoma cells. A great decrease was observed in the number and proliferative activity of splenic T cells in old mice after the stress. The decrease in young mice was rather temporary with a quick recovery. The number of NK cells in spleen was not different between young and old mice before giving the stress, but a significant decrease was observed in the old after the stress. NK activity was always much lower in old than in young throughout the experiment. The pattern of metastasis of B16 melanoma cells was different between young and old mice. Metastatic colonies in lungs were larger in number and bigger in size in young mice than in old mice. After the stress, the number increased and the size unchanged in old mice, while the size increased and the number remained unchanged in young mice. It was shown that the same restraint stress resulted in a more serious influence on the immune cells in old than in young mice and gave rise to a differential effect on the pattern of tumor metastasis between young and old mice.

Aging↗

PubMed1997

Impairment of signal transduction in T cells from old mice.

T cells from old mice showed impaired proliferative response to antigenic stimulation. To understand the mechanism underlying the age-related impairment of T cell functions, the signal transduction pathway was examined and compared between T cells from young and old mice, and between T cell clones established from a young and old mouse. The age-related changes in T cells were as follows: (1) reduction in the expression and the activation of protein tyrosine kinases associated with T cell receptor (TCR) after antigenic stimulation; (2) reduced phosphorylation of phospholipase C gamma 1 (PLC gamma 1); (3) reduced production of second messengers such as inositoltrisphosphate (IP3) and diacylglycerol (DAG); and (4) reduced influx of Ca2+ ion. Thus, a T cell clone established from an old mouse showed impaired proliferation by stimulation with anti-CD3 antibody, but was fully activated to the level of a T cell clone from a young mouse by stimulation with phorbol acetate myristate (PMA) plus ionomycin (INM). However, splenic T cells freshly prepared from old mice did not show full recovery by the same treatment. The results indicate that one major blockade in the signal transduction of T cells from old mice is present in the pathway just after TCR, but besides this, the blockade is also present in multiple sites down-stream, which can not be bypassed by stimulation with PMA plus INM.

Aging↗

PubMed1997

Aging of the recipients but not of the bone marrow donors enhances autoimmunity in syngeneic radiation chimeras.

Young and old mice have been lethally irradiated and injected with syngeneic bone marrow cells from young or old donors to investigate whether self reactivity in old mice results from age-related damage of the radioresistant stromal cells and/or of the bone marrow hematopoietic cells. Thymus and spleen cell repopulations and mitotic responses at 3 months after irradiation are lower in old than in young recipients, suggesting age-related accumulation of stromal cell damage in the thymus as well as in other central and peripheral lymphoid tissues. The same efficiency of bone marrow cells from young and old donors to repopulate the thymus and spleen in recipients of equal age rules out the detrimental effects of aging on stem cells as well as T and B cell precursors. The serum concentration of auto-antibody and glomerular lesions at 3 and 9 months after irradiation were more pronounced in old than in young recipients and displayed no difference in recipients of equal age, regardless of the age of the bone marrow cell donors. These findings support the possibility that age-related damage of stromal cells induces disregulation of the immune system leading to autoimmune phenomena.

Aging↗

PubMed1997

Altered expression of various receptors on T cells in young and old mice after mitogenic stimulation: a flow cytometric analysis.

To understand mechanism underlying the age-related impairment of T cell functions, changes in the expression of cell surface receptors were examined in T cells after mitogenic stimulation by flow cytometry and results were compared between young and old mice. Before stimulation, no significant difference was observed in the density of TCR alpha beta, CD3, CD122 (IL-2R beta), IL-2R gamma, CD28 and CD95 (Fas) of T cells between young and old mice. As for CD25(IL-2R alpha) and CTLA-4, relative intensity and percentage of positive cells were higher in old than in young mice, although the levels were low compared with those after stimulation. After mitogenic stimulation, increased expression of the density was observed in CD25, IL-2R beta, IL-2R gamma, CD28, CTLA-4 and CD95 and the magnitude of increase was more pronounced in T cells from young than those from old mice. The expression of TCR alpha beta and CD3 decreased after mitogenic stimulation, and the degree of expression quickly recovered to the initial level in young mice, but not in old mice. Lower expression of TCR, IL-2 receptors and co-stimulatory molecules in T cells from old mice could be responsible for the impaired proliferation after mitogenic stimulation.

Abatacept↗

PubMed1997

Induction of thymic hyperplasia and suppression of splenic T cells by lesioning of the anterior hypothalamus in aging Wistar rats.

The effect of destruction of the anterior hypothalamus (AHT) on the immune system was examined in rats 4-50 weeks after the treatment. The thymic weight significantly increased in the experimental group regardless of age, while a significant decrease was observed in the percentage of splenic T cells as well as their proliferative response to phytohemagglutinin (PHA). The increase of thymic weight was observed as long as 24 weeks and the decrease of splenic T cell number was observed as long as 50 weeks after the operation. Hypophysectomy gave rise to atrophy of both thymus and spleen, while either adrenalectomy or gonadectomy resulted in hypertrophy of both thymus and spleen. The results taken together suggest that development and aging of the immune system are under the balance of positive and negative signals from AHT.

Aging↗

PubMed1997

Positive and negative CD4+ thymocyte selection by a single MHC class II/peptide ligand affected by its expression level in the thymus.

The central event in thymic selection of T cells bearing alpha beta TCRs is their interaction with self-peptides bound to self-MHC molecules. With the use of transgenic mouse lines expressing a single peptide/MHC class II complex, we show that CD4+ T cells with the preferential usage of particular TCR V(alpha)s and V(beta)s were selected to mature on this complex in lines with the lower expression, whereas such CD4+ T cells were eliminated in the thymus in a line with the relatively high expression. When a low expressing line was crossed with a high expressing line, the frequency of CD4+ T cells selected by this complex markedly decreased. Thus, these results suggest that a single peptide/MHC class II complex, being affected by its cell surface density in the thymus, can serve as both positively and negatively selecting ligand in vivo.

Amino Acid Sequence↗

PubMed1997

Age-related changes of cytokine production by murine helper T cell subpopulations.

Mouse CD4+ T cells were subdivided into two subsets by cell surface markers: CD44loCD45RBhi (naive) and CD44hiCD45RBlo (memory) T cells. We have reported that CD44loCD45RBhi T cells, which are predominant in young mice, decreased with age, while CD44hiCD45RBlo T cells increased. Among T cells of the same phenotype, however, it remains to be solved whether or not there is a functional difference between young and old. Therefore, we compared old with young T cells by a cytokine production assay (IL-2, IFN-gamma, IL-4 and IL-10). We employed the negative selection method by cell affinity column instead of flow cytometry as it was important to use T cells not reacted with antibodies in the cytokine production assay and as the method is quick enough to preserve the viability of the cells. Then the divided T cells were stimulated with immobilized anti-CD3 epsilon monoclonal antibody (mAb). Young CD4+ T cells produced more IL-2 and IL-4 than aged CD4+ T cells, while aged CD4+ T cells produced more IL-10 than young cells. There was no distinct age-related change in IFN-gamma production. As concerns purified CD4+ T cell subpopulations, young CD44loCD45RBhi T cells produced more IL-2 (5.3-fold higher) than young CD44hiCD45RBlo T cells and much more IL-2 (> 10-fold higher) than both groups of aged T cells. Dramatic IFN-gamma production was found in young and old CD44hiCD45RBlo T cells and young CD44loCD45RBhi T cells; however, IFN-gamma production of old CD44loCD45RBhi T cells was much lower (1/16-1/20) than that of other cell groups. IL-4 production was mainly observed in the CD44hiCD45RBlo T cell group in both young and old mice, although the former produced more IL-4 (5.2-fold higher) than the latter. There was no remarkable difference between young and old mice in the pattern of IL-10 production. These phenomena could reveal functional heterogeneity of aged CD4+ T cell subpopulations under natural conditions. Even if the surface marker is the same, the pattern of cytokine production is different between young and old cells.

Aging↗

PubMed1997

Natural killer cell frequency and serum cytokine levels in monoclonal gammopathies: correlation of bone marrow granular lymphocytes to prognosis.

The percent of granular lymphocytes of total bone marrow lymphocytes was 12.5% in controls, 15% in myeloma and 27% in monoclonal gammopathy of undetermined significance (MGUS). A good correlation was found between the percent of granular lymphocytes in the bone marrow lymphocytes at diagnosis (Y) and the years of survival (X) from the diagnosis of either the IgG- or IgA-type myeloma. The linear regression equation calculated for the IgG-type myeloma was Y = 1.6X + 7.42, and for the IgA-type myeloma Y = 4.25X + 4.75. For the purpose of analyzing in detail the granular lymphocyte behavior, two-color analyses of peripheral blood mononuclear cells and the serum levels of cytokines were performed. The absolute number of CD3+ cells, CD4+CD45RA+ cells and CD4+CD29+ cells was lower in the multiple myeloma (MM) cases than that of MGUS or controls (p < 0.01). The CD57+CD16+ natural killer (NK) cells were lower in MM cases than in MGUS cases. The serum levels of IL-1, which may activate NK cells, were higher in the MGUS cases than in either myeloma cases or controls (p < 0.01). The IL-10 levels, which may inhibit the proliferation of NK cells, were higher in the myeloma cases than in the MGUS cases (p < 0.05). Detailed understanding of the cytokine network of myeloma patients and their NK cell frequency may be important for the investigation of M proteinemias and for the future strategic planning of biological modulation therapies of myeloma patients.

Aged↗

PubMed1996

Retardation of the age-associated decline of immune functions in aging rats under dietary restriction and daily physical exercise.

Wistar rats were subjected to dietary restriction and daily physical exercise for 21 months, starting from 2 months of age. At the age of 23 months, the rats were sacrificed and examined for various indices including immunological functions. Body weight was almost the same between rats fed ad libitum (Group A) and those (Group B) fed 80% of the diet consumed by Group A. The body weights of Groups A and B were significantly heavier than that of rats (Group C) fed 60% of the diet consumed by Group A and those (Group D) which were subjected to physical exercise and fed 80% of the diet consumed by Group A. Highly proliferative response of T cells to mitogens was observed in 5 out of 13 rats in group D. Some enhancement of B cell proliferation was also observed in the same rats. Present results suggested that enduring physical exercise together with dietary restriction can retard the age-related decrement of immunological functions.

Aging↗

PubMed1995

Expression of ZAP-70 gene in the developing thymus and various nonlymphoid tissues of embryonic and adult mice.

The full length of cDNA encoding murine ZAP-70 was obtained from a cDNA library of embryonic mouse thymus. Northern blot analysis indicated that the expression of ZAP-70 mRNA was most pronounced in the thymus and spleen and also slightly in the brain. Analysis by in situ hybridization revealed that the mRNA was expressed not only in T cells in the thymus and spleen, but also in nerve cells of the brain. In the thymus, the distribution of positive cells was different between newborn and young adult mice. In the newborn thymus, positive signal in thymocytes was localized in the subcapsular layer as well as in the medulla, while in the young adult thymus, it was localized exclusively in the medulla. Furthermore, the in situ hybridization revealed that positive signal was also seen in the liver, intestine, and lung of embryonic mice. These findings have suggested that ZAP-70 plays an important role in growth, differentiation, and function of not only T cells but also nerve cells and several embryonic tissues.

Amino Acid Sequence↗

PubMed1995

Differential expression of protein tyrosine kinases in the cortical and medullary thymic epithelial cell lines.

Expression of protein tyrosine kinase (PTK) was evaluated and compared between cortical and medullary thymic epithelial cell (TEC) lines, TEC 14C18 and TEC1C6, respectively. Reverse transcription-polymerase chain reaction (RT-PCR) methods using degenerate primers for conserved sequence in catalytic domain of PTK revealed the expression of 13 kinds of PTKs in these cell lines. These PTKs included 6 receptor and 7 non-receptor types. In the next step, we compared the intensity of mRNA expression level of these kinases between cortical and medullary TEC lines. Tyrosine kinases of receptor type were differentially expressed between cortical and medullary TEC lines; e.g., mRNA expression of flg was observed more intensively in the cortical TEC line than in the medullary one, while mRNA expression of bek, met and sky was vice versa. On the other hand, expression of non-receptor tyrosine kinases, including four JAK-tyk family members, are comparable in both lines. These results suggested that these PTKs, especially of receptor type, might play an important role in the development of the thymic microenvironment.

Amino Acid Sequence↗

PubMed1995

Differential effects of gonadectomy on thymic stromal cells in promoting T cell differentiation in mice.

Twenty-six week-old BDF1 mice were gonadectomized and grafted with thymus from irradiated (8.5 Gy) newborn, 6-week-old, or 26-week-old mice. One month later, grafted thymuses were recovered and examined in terms of thymocyte numbers, subpopulations and proliferative responses to Concananavlin A (Con A). The growth of the irradiated thymus was significantly higher in gonadectomized (Gx) than in sham-operated (Sham) mice and the magnitude of thymic growth was apparently age-dependent, as it was greater for newborns than for older mice. Con A response of thymocytes was also significantly higher in Gx mice than in Sham mice, and the magnitude of the response declined with advancing age of the thymus donors. Flow cytometric analysis revealed that a significant increase in the percentage of CD4+CD8- was observed in thymus grafts showing high Con A responses. However, this effect of Gx on the thymus graft was dependent on age of the thymus donor. Namely, newborn thymus grafts could grow equally well in both Gx and Sham recipients, whereas thymus grafts from 6- and 26-week-old mice could grow well only in Gx, but not in Sham recipients. The number of thymocytes was comparable in thymus grafts from 6- and 26-week-old mice, but the proliferative response to Con A was higher in the former than in the latter graft. Collectively, Gx appeared to promote immigration of thymocyte precursors into the thymus and to enhance proliferation and differentiation of thymocytes towards CD4+CD8- T cells, in an age-related manner.

Aging↗

PubMed1995

A novel type of cell death of lymphocytes induced by a monoclonal antibody without participation of complement.

A monoclonal antibody, RE2, raised by immunizing a rat with cell lysate of a mouse T cell clone, was found to directly kill interleukin 2-dependent T cell clones without participation of serum complement. Fab fragments of RE2 had no cytolytic activity, while the cross-linking of Fab fragments with anti-rat immunoglobulin reconstituted the cytotoxicity. The cytotoxicity was temperature dependent: the antibody could kill target cells at 37 degrees C but not at 0 degrees C. Sodium azide, ethylenediaminetetraacetic acid, and forskolin did not affect the cytolytic activity of RE2, while the treatment of target cells with cytochalasin B and D completely blocked the activity. This suggested that the cell death involves a cytoskeleton-dependent active process. Giant holes on the cell membrane were formed within 5 minutes after the treatment with RE2, as observed by scanning electron microscopy. There was no indication of DNA fragmentation nor swelling of mitochondria during the cytolysis, suggesting that the cell death is neither apoptosis nor typical necrosis. The antibody also killed T cell lymphomas and T and B cell hybridomas only when these cells were preactivated with concanavalin A, lipopolysaccharide, or phorbol myristate acetate. Preactivated peripheral T and B cells were sensitive to the cytotoxicity of RE2, while resting T and B cells were insensitive. These results provide evidence for a novel pathway of cell death of activated lymphocytes by membrane excitation.

Animals↗

PubMed1995

The role of thymus in the aging of Th cell subpopulations and age-associated alteration of cytokine production by these cells.

Mouse CD4+ T cells were subdivided into two subpopulations, naive (CD44low CD45RBhigh) and memory (CD44high CD45RBlow) T cells, by flow cytometric analysis. Examination of spleen and peripheral blood of C57BL/6 mice of various ages revealed that there was a reciprocal age-associated change in these two subpopulations, i.e. naive T cells predominant in young mice decreased with age, while memory T cells increased. In order to investigate the role of the thymus in the age change of naive and memory T cells, we employed two experimental systems: radiation bone marrow chimeras constructed between young and old mice, and grafting of young or old thymus into nude mice. Data from these two experiments suggested that the young thymus has a greater ability to provide naive T cells than the old thymus, while the old thymus favors the maintenance of memory T cells rather than naive T cells. In reference to cytokine production by enriched naive and memory T cells, young naive T cells produced mainly IL-2 and young memory T cells mainly IL-4. On the other hand, in old mice, memory T cells produced twice as much IL-2 than naive T cells, although the level was significantly lower than that of young mice. In addition, old naive T cells produced twice as much IL-4 than old memory T cells. These results suggested a distinct age change in the profile of cytokine production and functional heterogeneity of two Th cell subpopulations.

Age Factors↗

PubMed1995

The characterization of the monoclonal antibody Th-10a, specific for a nuclear protein appearing in the S phase of the cell cycle in normal thymocytes and its unregulated expression in lymphoma cell lines.

A monoclonal antibody (Th-10a) specific for the nuclear protein appearing in the S phase of the cell cycle in normal mouse thymocytes was derived by immunizing Wistar rats with a murine thymic lymphoma (TIGN), and its isotype was rat IgG2a and had kappa light chain. Immunohistochemical staining of frozen sections of B10.Thy1.1 newborn thymus and embryonic intestine revealed that this monoclonal antibody reacted strongly with the nuclear proteins of subcortical thymocytes and the basal layer of the mucosa, where many cells were dividing, but not with that of the thymic medullary area. To evaluate the expression of the nuclear proteins during the cell cycle in detail, the results of an immunofluorescence analysis of the thymocytes from hydroxyurea-treated B10 mice using Th-10a monoclonal antibody were compared with those of DNA synthesis of these cells with the use of the FITC-conjugated anti-BrdUrd monoclonal antibody. The results indicated that the nuclear protein detected by Th-10a monoclonal antibody was highly expressed in the S phase of normal thymocytes, while the cells in G1, G2 and M phases exhibited a low level of the expression. Moreover, the variations in expression of the nuclear proteins in the thymocytes at different times after hydroxyurea treatment were observed to correspond with the frequency of DNA synthesizing cells. In contrast, the high level and unregulated expression of the nuclear protein detected by Th-10a monoclonal antibody was observed throughout the cell cycle of the mouse lymphoma cell lines examined. Since Th-10a monoclonal antibody does not react with the nuclear proteins derived from human, hamster or rat proliferating cells, this antibody may recognize a murine specific epitope of the nuclear protein. To further characterize the nuclear proteins, we extracted them from normal thymocytes or thymic lymphomas, and analysed them by immunoblotting or immunoprecipitation followed by SDS-polyacrylamide gel electrophoresis. The nuclear protein(s) detected by Th-10a monoclonal antibody was mostly 95 kDa and also 83 kDa polypeptide. The results also indicated that the 95 kDa nuclear protein was phosphorylated in vivo.

Animals↗

PubMed1994

Understanding the mechanism of the age-change of thymic function to promote T cell differentiation.

Immunological functions peak at around puberty and gradually decline thereafter with advancing age. The immunological decline mainly occurs in the T cell-dependent immune system and is generally associated with an increase in not only susceptibility to infections but also incidence of autoimmune phenomena. The age-related changes in T-cell dependent immune functions can be mainly ascribed to the physiological thymic involution which starts in the early phase of life. The age-related thymic involution can be ascribed to either extrinsic or intrinsic factors. Bone marrow stem cells can be one of the extrinsic factors for the thymic involution, but their role is estimated to be marginal as compared with alteration of the thymic microenvironment. With advancing age, the thymic capacity to promote T-cell differentiation declines together with a change in the composition of T-cell subsets produced. Such an alteration of the thymic environment is responsible for the age-related change in peripheral T cells in number and in composition. Age change is observed in several intrinsic factors in the thymic environment which influence proliferation of thymocytes. These thymic intrinsic factors can either promote or inhibit proliferation of thymocytes, and promoting factors generally decrease with age with a concomitant increase in inhibitory factors. Various endocrine hormones are important extrinsic factors influencing the thymic function. In fact, physiological thymic involution can be intervened by manipulation of the endocrine system, sometimes resulting in rejuvenation of immune functions to a certain extent.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗

PubMed1994

Changes in the subsets of CD4+ T cells in Trypanosoma musculi infection: delay of immunological cure in young mice and the weak ability of aged mice to control the infection.

After a 3 week course (approximately), during which there is marked lymphoid hyperplasia, Trypanosoma musculi infections in young-adult mice are cured by an immune mechanism involving antibodies of the IgG2a isotype. Both the lymphoid hyperplasia and IgG2a antibody response are T-cell-dependent events and both processes appear to be defective in aged mice. The purpose of the studies reported here was to elucidate the effects of T. musculi infection on subsets of T cells for two reasons: (i) to gain insight into the probable roles of selected cytokines (IL-2, IL-4 and IFN-gamma) in facilitating the production of curative, IgG2a antibodies, and (ii) to examine the hypothesis that aging affects the competence of CD4+ T cells to participate in immunological control of infections. The major conclusions from these studies are that: (i) T. musculi infection of mice induces rapid change in the CD4+ T cell population toward predominance of the activated or memory (CD45RBloCD44hi) phenotype, cells which produce IFN-gamma, II-3, IL-4 and IL-5, accompanied by profound inhibition of IL-2 production, and (ii) in the old mice these changes are superimposed on the natural age-associated changes in the same direction (i.e. toward predominance of CD45RBloCD44hi T cells). Thus, in the old animals, the combined changes of aging and infection, moving in the same direction, are devastating, resulting in the aged animals being unable, or barely able, to control infection.

Aging↗

PubMed1994

Epithelial class II MHC antigen normally expressed by submandibular glands of elderly people.

Immunohistochemical studies were made on 81 submandibular glands obtained from over 60-year-old autopsy cases. Those patients who had had either sialolithiasis or autoimmune diseases were not included in this study. HLA-DR expression was observed in the great majority (95.1%) of the aged submandibular glands, especially on the serous acinar cells and the intercalated duct cells, regardless of the appearance of focal lymphocytic infiltration. The incidence of HLA-DP expression was slightly lower (85.2%) and HLA-DQ was much lower (42.0%) than that of HLA-DR. These data support the proposal that epithelial expression of class II antigens in aged glands is a focal sign of age-related immunological disorders.

Aged↗