Differential MHC expression requirements for positive selection of separate TCR Vb families
| Autor: | Jan Böhme, N. Brenden |
|---|---|
| Rok vydání: | 1999 |
| Předmět: |
CD4-Positive T-Lymphocytes
Genetically modified mouse Receptors Antigen T-Cell alpha-beta Immunology Clonal Deletion Bone Marrow Cells Mice Transgenic Thymus Gland CD8-Positive T-Lymphocytes Major histocompatibility complex Clonal deletion Autoimmune Diseases Mice Mice Inbred NOD T-Lymphocyte Subsets mental disorders Genetics medicine Animals Gene Rearrangement beta-Chain T-Cell Antigen Receptor Bone Marrow Transplantation NOD mice biology T-cell receptor Histocompatibility Antigens Class II Molecular biology Epithelium Mice Inbred C57BL Diabetes Mellitus Type 1 medicine.anatomical_structure Radiation Chimera biology.protein Female Bone marrow CD8 |
| Zdroj: | Immunogenetics. 49:1-6 |
| ISSN: | 1432-1211 0093-7711 |
| DOI: | 10.1007/s002510050457 |
| Popis: | Positive selection has been proposed to be involved in protection from diabetes. We examined positive selection by fluorescence-activated cell sorter analyses in thymocytes of protected and susceptible E-transgenic and non-transgenic NOD mice. Three Vb families showed positive selection in E-transgenic mice. Vb6(+)CD4(+) and Vb10(+)CD4(+) thymocytes were found at higher frequencies in both protected NOD-Ea and susceptible NOD-DY mice. The increased frequencies of Vb13(+)CD8(+) thymocytes were found in protected NOD-Ea mice only, and not in susceptible NOD-DY transgenic mice. These three Vb families were further examined in bone-marrow chimeras between NOD-Ea and non-transgenic NOD mice, where we could examine the contribution of E-expressing bone-marrow-derived cells in positive selection. We find that NOD-Ea--NOD-Ea chimeras have an increased positive selection of Vb13(+)CD8(+) cells and that positive selection is more efficient when both thymic epithelium and bone-marrow-derived cells express the E molecule. This was also seen for Vb6(+)CD4(+) cells. However, for Vb6, bone-marrow-derived cells alone were also capable of positive selection. Positive selection of Vb10(+)CD4(+) cells was restricted to E-expressing thymic epithelium only. For Vb13(+)CD8(+ )cells, we found that positive selection is most efficient with E-expression on both thymic epithelium and bone-marrow-derived cells, although positive selection also occurs with E-positive epithelium only. For Vb6(+) CD4(+) cells, the dominating selecting cells are bone-marrow-derived cells, and Vb10(+)CD4(+ )cells seem to be selected exclusively by the thymic epithelium. Thus, the conditions for positive selection seem to vary considerably between different Vb families. |
| Databáze: | OpenAIRE |
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