徳島大学 教育・研究者情報データベース(EDB)

1. 安友 康二([徳島大学.大学院医歯薬学研究部.医学域.医科学部門.病理系.生体防御医学])

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2. (英) Lucas Bruno

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3. (英) Germain N Ronald

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(英) TCR signaling for initiation and completion of thymocyte positive selection has distinct requirements for ligand quality and presenting cell type

(英) Thymocyte selection involves signaling by TCR engaging diverse self-peptide:MHC molecule ligands on various cell types in the cortex and medulla. Here we separately analyze early and late stages of selection to better understand how presenting cell type, ligand quality, and the timing of TCR signaling contribute to intrathymic differentiation. TCR transgenic CD4+CD8+ thymocytes (double positive (DP)) from MHC-deficient mice were stimulated using various presenting cells and ligands. The resulting CD69high cells were isolated and evaluated for maturation in reaggregate cultures with wild-type or MHC molecule-deficient thymic stroma with or without added hemopoietic dendritic cells (DC). Production of CD4+ T cells required TCR signaling in the reaggregates, indicating that transient recognition of self-ligands by DP is inadequate for full differentiation. DC bearing a potent agonist ligand could initiate positive selection, producing activated thymocytes that matured into agonist-responsive T cells in reaggregates lacking the same ligand. DC could also support the TCR signaling necessary for late maturation. These results argue that despite the negative role assigned to DC in past studies, neither the peptide:MHC molecule complexes present on DC nor any other signals provided by these cells stimulate only thymocyte death. These findings also indicate that unique epithelial ligands are not necessary for positive selection. They provide additional insight into the role of ligand quality in selection events and support the concept that following initiation of maturation from the DP state, persistent TCR signaling is characteristic of and perhaps required by T cells.

1. (英) Animals
2. (英) Antigen-Presenting Cells
3. (英) Antigens, CD
4. (英) Antigens, CD4
5. (英) Antigens, CD8
6. (英) Antigens, Differentiation, T-Lymphocyte
7. (英) CD4-Positive T-Lymphocytes
8. (英) Cell Aggregation
9. (英) Cell Differentiation
10. (英) Cell Survival
11. (英) Cells, Cultured
12. (英) Cytochrome c Group
13. (英) Dendritic Cells
14. (英) Histocompatibility Antigens Class II
15. (英) Immunophenotyping
16. (英) Lectins, C-Type
17. (英) Ligands
18. (英) Lymphocyte Activation
19. (英) Major Histocompatibility Complex
20. (英) Mice
21. (英) Mice, Inbred C57BL
22. (英) Mice, Knockout
23. (英) Mice, Transgenic
24. (英) Peptides
25. (英) Proto-Oncogene Proteins c-bcl-2
26. (英) Receptors, Antigen, T-Cell
27. (英) Signal Transduction
28. (英) Stromal Cells
29. (英) T-Lymphocyte Subsets
30. (英) Thymus Gland
31. (英) Up-Regulation

1. (英) Article.PublicationTypeList.PublicationType: Journal Article

2. (英) Article.PublicationTypeList.PublicationType: Research Support, Non-U.S. Gov't