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Role of different T cell receptors in the development of pre-T cells.

Buer J, Aifantis I, DiSanto JP, Fehling HJ, von Boehmer H - J. Exp. Med. (1997)

Bottom Line: The development of pre-T cells with productive TCR-beta rearrangements can be mediated by each the pre-T cell receptor (pre-TCR), the TCR-alphabeta as well as the TCR-gammadelta, albeit by distinct mechanisms.The TCR-alphabeta appears to be much less effective than the pre-TCR because of the paucity of TCR-alpha proteins in TCR-beta-positive precursors since an early expressed transgenic TCR-alphabeta can largely substitute for the pre-TCR.In evolution this double function of the TCR-alphabeta may have been responsible for the maturation of alphabeta T cells before the advent of the pre-TCR-alpha chain.

View Article: PubMed Central - PubMed

Affiliation: Institut Necker, Institut National de la Sante et de la Recherche Medicale, Paris, France.

ABSTRACT
The development of pre-T cells with productive TCR-beta rearrangements can be mediated by each the pre-T cell receptor (pre-TCR), the TCR-alphabeta as well as the TCR-gammadelta, albeit by distinct mechanisms. Although the TCR-gammadelta affects CD4-8- precursor cells irrespective of their rearrangement status by TCR-beta mechanisms not involving TCR-beta selection, both the pre-TCR and the TCR-alphabeta select only cells with productive TCR-beta genes for expansion and maturation. The TCR-alphabeta appears to be much less effective than the pre-TCR because of the paucity of TCR-alpha proteins in TCR-beta-positive precursors since an early expressed transgenic TCR-alphabeta can largely substitute for the pre-TCR. Thus, the TCR-alphabeta can assume a role not only in the rescue from programmed cell death of CD4+8+ but also of CD4-8- thymocytes. In evolution this double function of the TCR-alphabeta may have been responsible for the maturation of alphabeta T cells before the advent of the pre-TCR-alpha chain.

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Comparision of surface phenotype of  thymocytes from TCR-αβ pTα−/− vs. TCR-αβ  transgenic mice. (Top) total thymocytes were double stained for CD4 (FITC-conjugated anti-CD4)  and CD8 (RED613-conjugated anti-CD8) surface  antigens as described. Percentages and absolute  numbers of thymocytes (in brackets) are given.  TCR-αβ pTα−/− transgenic mice contained approximately one-half of the number of thymocytes  found in TCR-αβ transgenic mice (2,870 × 104  vs. 4,720 × 104 cells). (Bottom) cells were stained  with FITC-conjugated CD4 and CD8 antibodies  in combination with biotinylated CD44 and PEconjugated anti-CD25 antibodies. Biotin was detected with a streptavidin–PE conjugate. The expression of CD25 and CD44 was analyzed by  three-color flow cytometry, using electronic gating  to exclude FITC-positive cells. The percentages of  cells in each quadrant are indicated.
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Figure 3: Comparision of surface phenotype of thymocytes from TCR-αβ pTα−/− vs. TCR-αβ transgenic mice. (Top) total thymocytes were double stained for CD4 (FITC-conjugated anti-CD4) and CD8 (RED613-conjugated anti-CD8) surface antigens as described. Percentages and absolute numbers of thymocytes (in brackets) are given. TCR-αβ pTα−/− transgenic mice contained approximately one-half of the number of thymocytes found in TCR-αβ transgenic mice (2,870 × 104 vs. 4,720 × 104 cells). (Bottom) cells were stained with FITC-conjugated CD4 and CD8 antibodies in combination with biotinylated CD44 and PEconjugated anti-CD25 antibodies. Biotin was detected with a streptavidin–PE conjugate. The expression of CD25 and CD44 was analyzed by three-color flow cytometry, using electronic gating to exclude FITC-positive cells. The percentages of cells in each quadrant are indicated.

Mentions: The fact that in the absence of the pre-TCR the generation of CD4+8+ cells by the TCR-αβ is rather inefficient, i.e., 240 × 104 versus 2,880 × 104 in pTα−/− TCR-δ−/− versus wild-type mice, could depend on the fact that the TCR-αβ is inefficiently formed in CD4−8− cells due to the late TCR-α rearrangement and/or the fact that TCR-αβ can only inefficiently replace the pre-TCR. To analyze this question in some more detail we studied mice that express a transgenic TCR-αβ early in development on CD4−8− cells, i.e., TCR-αβ transgenic pTα−/− mice. The transgenic TCR-αβ could indeed overcome the cellular deficiency in the CD4+8+ compartment as TCR-αβ transgenic pTα−/− mice contained approximately one-half the number of thymocytes found in TCR-αβ transgenic pTα+ mice and many more than the number found in nontransgenic pTα−/− mice (Fig. 3). However, there was a subtle difference between TCR-αβ transgenic pTα+ and TCR-αβ transgenic pTα−/− mice in that the latter, but not the former, contained a discrete subset of CD25+ cells, indicating that in spite of the presence of the transgenic TCR-αβ, the preTCR had its role in the exit from this compartment. This could be due to the lack of expression of the transgenic TCR-αβ in a fraction of cells in the CD25+ compartment of the TCR-αβ transgenic, pTα−/− mice. This was in fact confirmed by cytoplasmic staining: while only nine percent of CD25+ cells in TCR-αβ transgenic pTα−/− mice expressed the transgenic TCR-α chain the majority of these cells expressed the transgenic TCR-β chain suggesting that expression of the two transgenes is differentially regulated (Fig. 4). Thus, in TCR-αβ transgenic pTα+ mice it is the combined action of the pre-TCR and the TCR-αβ (mice that have only a TCR-β transgene still exhibit a significantly larger CD25+ compartment than TCR-αβ transgenic mice, not shown) that reduce the number of CD25+ cells while in TCR-αβ transgenic pTα−/− mice this compartment is bigger in size because of the absence of the preTCR. From these data it would appear that the TCR-αβ can at least partially mimic the function of the pre-TCR and that in normal mice the contribution of the TCR-αβ to the generation of the CD4+8+ compartment is limited due to relatively late expression of most TCR-α chains (1, 2).


Role of different T cell receptors in the development of pre-T cells.

Buer J, Aifantis I, DiSanto JP, Fehling HJ, von Boehmer H - J. Exp. Med. (1997)

Comparision of surface phenotype of  thymocytes from TCR-αβ pTα−/− vs. TCR-αβ  transgenic mice. (Top) total thymocytes were double stained for CD4 (FITC-conjugated anti-CD4)  and CD8 (RED613-conjugated anti-CD8) surface  antigens as described. Percentages and absolute  numbers of thymocytes (in brackets) are given.  TCR-αβ pTα−/− transgenic mice contained approximately one-half of the number of thymocytes  found in TCR-αβ transgenic mice (2,870 × 104  vs. 4,720 × 104 cells). (Bottom) cells were stained  with FITC-conjugated CD4 and CD8 antibodies  in combination with biotinylated CD44 and PEconjugated anti-CD25 antibodies. Biotin was detected with a streptavidin–PE conjugate. The expression of CD25 and CD44 was analyzed by  three-color flow cytometry, using electronic gating  to exclude FITC-positive cells. The percentages of  cells in each quadrant are indicated.
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Related In: Results  -  Collection

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Figure 3: Comparision of surface phenotype of thymocytes from TCR-αβ pTα−/− vs. TCR-αβ transgenic mice. (Top) total thymocytes were double stained for CD4 (FITC-conjugated anti-CD4) and CD8 (RED613-conjugated anti-CD8) surface antigens as described. Percentages and absolute numbers of thymocytes (in brackets) are given. TCR-αβ pTα−/− transgenic mice contained approximately one-half of the number of thymocytes found in TCR-αβ transgenic mice (2,870 × 104 vs. 4,720 × 104 cells). (Bottom) cells were stained with FITC-conjugated CD4 and CD8 antibodies in combination with biotinylated CD44 and PEconjugated anti-CD25 antibodies. Biotin was detected with a streptavidin–PE conjugate. The expression of CD25 and CD44 was analyzed by three-color flow cytometry, using electronic gating to exclude FITC-positive cells. The percentages of cells in each quadrant are indicated.
Mentions: The fact that in the absence of the pre-TCR the generation of CD4+8+ cells by the TCR-αβ is rather inefficient, i.e., 240 × 104 versus 2,880 × 104 in pTα−/− TCR-δ−/− versus wild-type mice, could depend on the fact that the TCR-αβ is inefficiently formed in CD4−8− cells due to the late TCR-α rearrangement and/or the fact that TCR-αβ can only inefficiently replace the pre-TCR. To analyze this question in some more detail we studied mice that express a transgenic TCR-αβ early in development on CD4−8− cells, i.e., TCR-αβ transgenic pTα−/− mice. The transgenic TCR-αβ could indeed overcome the cellular deficiency in the CD4+8+ compartment as TCR-αβ transgenic pTα−/− mice contained approximately one-half the number of thymocytes found in TCR-αβ transgenic pTα+ mice and many more than the number found in nontransgenic pTα−/− mice (Fig. 3). However, there was a subtle difference between TCR-αβ transgenic pTα+ and TCR-αβ transgenic pTα−/− mice in that the latter, but not the former, contained a discrete subset of CD25+ cells, indicating that in spite of the presence of the transgenic TCR-αβ, the preTCR had its role in the exit from this compartment. This could be due to the lack of expression of the transgenic TCR-αβ in a fraction of cells in the CD25+ compartment of the TCR-αβ transgenic, pTα−/− mice. This was in fact confirmed by cytoplasmic staining: while only nine percent of CD25+ cells in TCR-αβ transgenic pTα−/− mice expressed the transgenic TCR-α chain the majority of these cells expressed the transgenic TCR-β chain suggesting that expression of the two transgenes is differentially regulated (Fig. 4). Thus, in TCR-αβ transgenic pTα+ mice it is the combined action of the pre-TCR and the TCR-αβ (mice that have only a TCR-β transgene still exhibit a significantly larger CD25+ compartment than TCR-αβ transgenic mice, not shown) that reduce the number of CD25+ cells while in TCR-αβ transgenic pTα−/− mice this compartment is bigger in size because of the absence of the preTCR. From these data it would appear that the TCR-αβ can at least partially mimic the function of the pre-TCR and that in normal mice the contribution of the TCR-αβ to the generation of the CD4+8+ compartment is limited due to relatively late expression of most TCR-α chains (1, 2).

Bottom Line: The development of pre-T cells with productive TCR-beta rearrangements can be mediated by each the pre-T cell receptor (pre-TCR), the TCR-alphabeta as well as the TCR-gammadelta, albeit by distinct mechanisms.The TCR-alphabeta appears to be much less effective than the pre-TCR because of the paucity of TCR-alpha proteins in TCR-beta-positive precursors since an early expressed transgenic TCR-alphabeta can largely substitute for the pre-TCR.In evolution this double function of the TCR-alphabeta may have been responsible for the maturation of alphabeta T cells before the advent of the pre-TCR-alpha chain.

View Article: PubMed Central - PubMed

Affiliation: Institut Necker, Institut National de la Sante et de la Recherche Medicale, Paris, France.

ABSTRACT
The development of pre-T cells with productive TCR-beta rearrangements can be mediated by each the pre-T cell receptor (pre-TCR), the TCR-alphabeta as well as the TCR-gammadelta, albeit by distinct mechanisms. Although the TCR-gammadelta affects CD4-8- precursor cells irrespective of their rearrangement status by TCR-beta mechanisms not involving TCR-beta selection, both the pre-TCR and the TCR-alphabeta select only cells with productive TCR-beta genes for expansion and maturation. The TCR-alphabeta appears to be much less effective than the pre-TCR because of the paucity of TCR-alpha proteins in TCR-beta-positive precursors since an early expressed transgenic TCR-alphabeta can largely substitute for the pre-TCR. Thus, the TCR-alphabeta can assume a role not only in the rescue from programmed cell death of CD4+8+ but also of CD4-8- thymocytes. In evolution this double function of the TCR-alphabeta may have been responsible for the maturation of alphabeta T cells before the advent of the pre-TCR-alpha chain.

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