| Autor: |
Borgulya, P., Kishi, H., Müller, U., Kirberg, J., von Boehmer, H. |
| Zdroj: |
The EMBO Journal; April 1991, Vol. 10 Issue: 4 p913-918, 6p |
| Abstrakt: |
T cells bearing the alpha beta T cell receptor (TCR) can be divided into CD4+8‐ and CD4–8+ subsets which develop in the thymus from CD4+8+ precursors. The commitment to the CD4 and CD8 lineage depends on the binding of the alpha beta TCR to thymic major histocompatibility complex (MHC) coded class II and class I molecules, respectively. In an instructive model of lineage commitment, the binding of the alpha beta TCR, for instance to class I MHC molecules, would generate a specific signal instructing the CD4+8+ precursors to switch off the expression of the CD4 gene. In a selective model, the initial commitment, i.e. switching off the expression of either the CD4 or the CD8 gene would be a stochastic event which is then followed by a selective step rescuing only CD4+ class II and CD8+ class I specific T cells while CD4+ class I and CD8+ class II specific cells would have a very short lifespan. The selective model predicts that a CD8 transgene which is expressed in all immature and mature T cells should rescue CD4+ class I MHC specific T cells from cell death. We have performed experiments in CD8 transgenic mice which fail to support a selective model and we present data which show that the binding of the alpha beta TCR to thymic class I MHC molecules results in up‐regulation of the TCR in the CD4+8+ population. Therefore, these experiments are consistent with an instructive model of lineage commitment. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
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