Analysis of thymic stromal cell subpopulations grown in vitro on extracellular matrix in defined medium. II. Cytokine activities in murine thymic epithelial and mesenchymal cell culture supernatants.

Eshel, Ilana; Savion, Naphtali; Shoham, Jacob

doi:10.4049/jimmunol.144.5.1563

Cited by 25 publications

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“…Thymic epithelial cells, as well as other stromal elements, have been suggested to be intimately involved in the many facets of T-cell differentiation [14,15]. We have demonstrated that stromal cells exert their effects by both direct contact and by the secretion of soluble factors [16][17][18][19][20][21]. However, the mechanism that underlies these activities is poorly understood.…”

Section: Introductionmentioning

confidence: 99%

Induction of Apoptosis and p53 Expression in Immature Thymocytes by Direct Interaction with Thymic Epithelial Cells

et al. 1996

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Apoptosis of normal thymocytes was shown to be triggered by several mechanisms (e.g. glucocorticoids, gamma-irradiation). In the present study the authors report on thymocyte apoptosis that is induced by thymic epithelial cells. The thymocytes undergo a massive apoptotic death within 24 h of cocultivation with thymic epithelial cell monolayers derived from primary cultures (PTEC) or from a thymic epithelial cell line (TEC). Non-thymic monolayers were inactive. Apoptosis induction in this experimental model requires direct contact between the thymocytes and the thymic epithelial monolayer and can be blocked by anti-CD2 and anti-LFA-1 antibodies. The immature CD3-/+dull CD4+CD8+ thymocytes were the cells which undergo apoptosis. The fact that the authors are dealing with a massive apoptotic process of immature cells in the absence of exogenous antigen suggests that it involves the nonselected thymocytes. The apoptotic pathway selected by thymocytes following their culturing on TEC involves p53 expression. Indeed it was found that TEC-induced apoptosis, led to the accumulation of p53 protein that preceded the step of DNA fragmentation in freshly isolated thymocytes as well as in a glucocorticoid resistant thymoma cell line. Since glucocorticoid-induced thymocyte apoptosis is p53-independent, glucocorticoids are conceivably not involved in TEC-induced thymocyte death. The in vitro experimental model presented here may reflect the physiological sequence of events leading to thymocyte death in the thymus.

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Section: Introductionmentioning

confidence: 99%

Induction of Apoptosis and p53 Expression in Immature Thymocytes by Direct Interaction with Thymic Epithelial Cells

et al. 1996

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Thymic epithelial cell culture

Røpke

1997

Microsc. Res. Tech.

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Culture of epithelial cells from the thymus of children and laboratory animals has been used for more than two decades to evaluate both the nature of these cells and their importance in the selection and maturation of functional T cells. Especially by the use of serum‐free cultures and by establishment of cell lines from cultured thymic epithelial cells (TEC), it has been possible to obtain basic information on morphology of subpopulations of TEC, including surface determinants of importance for interactions with T‐cell precursors, and on the repertoire of cytokines secreted by different types of TEC. The available information, obtained by co‐culture of pre‐T cells and TEC, on the effects of TEC on the fate of pre‐T cells suggests that cultured TEC/TEC lines are able both to secrete needed cytokines for T‐cell development, and to deliver signals needed for T‐cell selection. In vivo results showing cross‐talk between TEC and T cells indicate that more careful evaluation of interactions between well‐defined subtypes of cultured TEC and co‐cultured subpopulations of pre‐T cells (as well as macrophages/dendritic cells) will be of importance in evaluation of the function of the thymus. Microsc. Res. Tech. 38:276–286, 1997. © 1997 Wiley‐Liss, Inc.

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The role of vitamin E in T‐cell differentiation and the decrease of cellular immunity with aging

Moriguchi

1998

BioFactors

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The purpose of this study is to investigate the effects of vitamin E on both the decrease of cellular immunity with aging (Section 2) and the differentiation of T-cells in thymus (Section 3). In Section 2, spontaneously hypertensive rats (SHR) as a model for aging were used in this experiment and fed regular (50 IU/kg diet) or a high vitamin E (500 IU/kg diet) diet for 6 weeks. At 12 weeks old, they were killed and assayed. Although proliferation of thymic lymphocytes was significantly decreased in SHR fed the regular diet compared to that of Wistar Kyoto rats (WKY) fed the same diet, the high vitamin E diet induced higher proliferation of thymic lymphocytes in SHR, which was almost the same as that of WKY fed the regular diet. In addition, the expressions of both CD4 and CD8 antigens on CD4+ CD8+ T-cells were also decreased in SHR, which was significantly improved by a high vitamin E diet. These results suggest that a high vitamin E diet enhances thymic lymphocyte proliferation through increased T-cell differentiation in the thymus. Then, the effect of vitamin E on T-cell differentiation in the thymus was investigated by using male Fisher rats. Rats were divided into three groups; vitamin E-free, regular and high vitamin E groups and fed a diet containing various levels of vitamin E (0, 50 and 500 IU/kg diet) for 7 weeks. Although the proportions of CD4+ CD8- and CD4- CD8+ T-cells in thymocytes were significantly greater in the high vitamin E group, the proportion of CD4+ CD8- T-cells inversely decreased in the vitamin E-free group compared to that of the regular group. We have tried to investigate the mechanism on the increased T-cell differentiation in the thymus of rats fed the high vitamin E diet through cytokine production, thymic epithelial cell (TEC) and macrophage functions. As their results, we have found that vitamin E enhances T-cell differentiation through the increase of not macrophage but TEC function in the thymus, which is associated with the increased binding capacity of TEC to immature T-cells via increased expression of the adhesion molecule, ICAM-1. These results suggest that vitamin E is a potent nutrient for promoting health in the aged via the improvement of cellular immunity decreased with aging.

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Analysis of thymic stromal cell subpopulations grown in vitro on extracellular matrix in defined medium. II. Cytokine activities in murine thymic epithelial and mesenchymal cell culture supernatants.

Cited by 25 publications

References 0 publications

Induction of Apoptosis and p53 Expression in Immature Thymocytes by Direct Interaction with Thymic Epithelial Cells

Induction of Apoptosis and p53 Expression in Immature Thymocytes by Direct Interaction with Thymic Epithelial Cells

Thymic epithelial cell culture

The role of vitamin E in T‐cell differentiation and the decrease of cellular immunity with aging

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