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The common cytokine receptor gamma chain and the pre-T cell receptor provide independent but critically overlapping signals in early alpha/beta T cell development.

Di Santo JP, Aifantis I, Rosmaraki E, Garcia C, Feinberg J, Fehling HJ, Fischer A, von Boehmer H, Rocha B - J. Exp. Med. (1999)

Bottom Line: Interleukin (IL)-7 interactions with its cognate receptor complex (IL-7Ralpha coupled to the common cytokine receptor gamma chain, gammac) play a dominant role in early thymopoiesis.We demonstrate that gammac-dependent cytokines do not appear to be required for normal pre-TCR function, and that the rate-limiting step in alpha/beta T cell development in gammac- mice does not involve TCR-beta chain rearrangements, but rather results from poor maintenance of early thymocytes.Thus, a series of overlapping signals derived from cytokine and T cell receptors guide the process of alpha/beta thymocyte development.

View Article: PubMed Central - PubMed

Affiliation: Institut National de la Santé et de la Recherche Médicale (INSERM) U429, Hôpital Necker-Enfants Malades, F-75743 Paris, France. disanto@nexker.fr

ABSTRACT
Intracellular signals emanating from cytokine and antigen receptors are integrated during the process of intrathymic development. Still, the relative contributions of cytokine receptor signaling to pre-T cell receptor (TCR) and TCR-mediated differentiation remain undefined. Interleukin (IL)-7 interactions with its cognate receptor complex (IL-7Ralpha coupled to the common cytokine receptor gamma chain, gammac) play a dominant role in early thymopoiesis. However, alpha/beta T cell development in IL-7-, IL-7Ralpha-, and gammac-deficient mice is only partially compromised, suggesting that additional pathways can rescue alpha/beta T lineage cells in these mice. We have investigated the potential interdependence of gammac- and pre-TCR-dependent pathways during intrathymic alpha/beta T cell differentiation. We demonstrate that gammac-dependent cytokines do not appear to be required for normal pre-TCR function, and that the rate-limiting step in alpha/beta T cell development in gammac- mice does not involve TCR-beta chain rearrangements, but rather results from poor maintenance of early thymocytes. Moreover, mice double mutant for both gammac and pre-Talpha show vastly reduced thymic cellularity and a complete arrest of thymocyte differentiation at the CD44(+)CD25(+) cell stage. These observations demonstrate that the pre-TCR provides the gammac-independent signal which allows alpha/beta T cell development in gammac- mice. Thus, a series of overlapping signals derived from cytokine and T cell receptors guide the process of alpha/beta thymocyte development.

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Early thymocyte development in control and γc− mice. (A) Thymocytes from 3–4-wk-old γc-deficient mice and their littermate controls  were stained using CD4-PE and CD8β-FITC, and absolute numbers of DN, DP, CD4 SP, and CD8 SP cells were calculated (mean ± SD from 10 mice  of each genotype). (B) Thymocytes were stained with a combination of FITC-conjugated antibodies (CD3, CD4, CD8β, TCR-α/β, TCR-γ/δ, B220,  DX5, and Gr-1), CD44-PE, and CD25-biotin followed by streptavidin-TRI. CD44 versus CD25 expression is shown on electronically gated FITC−  TN thymocytes. Absolute numbers were calculated (mean ± SD) from six mice of each genotype.
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Figure 1: Early thymocyte development in control and γc− mice. (A) Thymocytes from 3–4-wk-old γc-deficient mice and their littermate controls were stained using CD4-PE and CD8β-FITC, and absolute numbers of DN, DP, CD4 SP, and CD8 SP cells were calculated (mean ± SD from 10 mice of each genotype). (B) Thymocytes were stained with a combination of FITC-conjugated antibodies (CD3, CD4, CD8β, TCR-α/β, TCR-γ/δ, B220, DX5, and Gr-1), CD44-PE, and CD25-biotin followed by streptavidin-TRI. CD44 versus CD25 expression is shown on electronically gated FITC− TN thymocytes. Absolute numbers were calculated (mean ± SD) from six mice of each genotype.

Mentions: We analyzed intrathymic development in γc− mice to better define the nature of any developmental blocks resulting from the absence of γc. When comparing absolute numbers of CD4−CD8− double negative (DN) cells, CD4+CD8+ double positive (DP) cells, and CD4+CD8− and CD4−CD8+ single positive (SP) mature T cells, the DN and CD8 SP populations were more affected by the absence of γc (Fig. 1 A). While both DP and CD4 SP cells were reduced by 15–20-fold (similar to the overall decrease in thymic cellularity), the DN and CD8 SP subsets were reduced almost 40-fold. The DN compartment contains both early thymocyte precursors (CD3−) as well as mature CD3+ TCR-γ/δ and TCR-α/β cells. While γ/δ T cells do not develop in γc− mice (4, 28), DN α/β T cells are present (32). To specifically evaluate γc− TCR− thymocyte progenitors, we studied CD44 and CD25 expression on CD3−CD4−CD8− (TN) thymocytes by four-color immunofluorescence analysis. Previous studies have demonstrated that these cells differentiate through the following stages: CD44+CD25− → CD44+CD25+ → CD44−CD25+ → CD44−CD25− (33; for a review, see reference 34).


The common cytokine receptor gamma chain and the pre-T cell receptor provide independent but critically overlapping signals in early alpha/beta T cell development.

Di Santo JP, Aifantis I, Rosmaraki E, Garcia C, Feinberg J, Fehling HJ, Fischer A, von Boehmer H, Rocha B - J. Exp. Med. (1999)

Early thymocyte development in control and γc− mice. (A) Thymocytes from 3–4-wk-old γc-deficient mice and their littermate controls  were stained using CD4-PE and CD8β-FITC, and absolute numbers of DN, DP, CD4 SP, and CD8 SP cells were calculated (mean ± SD from 10 mice  of each genotype). (B) Thymocytes were stained with a combination of FITC-conjugated antibodies (CD3, CD4, CD8β, TCR-α/β, TCR-γ/δ, B220,  DX5, and Gr-1), CD44-PE, and CD25-biotin followed by streptavidin-TRI. CD44 versus CD25 expression is shown on electronically gated FITC−  TN thymocytes. Absolute numbers were calculated (mean ± SD) from six mice of each genotype.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2192922&req=5

Figure 1: Early thymocyte development in control and γc− mice. (A) Thymocytes from 3–4-wk-old γc-deficient mice and their littermate controls were stained using CD4-PE and CD8β-FITC, and absolute numbers of DN, DP, CD4 SP, and CD8 SP cells were calculated (mean ± SD from 10 mice of each genotype). (B) Thymocytes were stained with a combination of FITC-conjugated antibodies (CD3, CD4, CD8β, TCR-α/β, TCR-γ/δ, B220, DX5, and Gr-1), CD44-PE, and CD25-biotin followed by streptavidin-TRI. CD44 versus CD25 expression is shown on electronically gated FITC− TN thymocytes. Absolute numbers were calculated (mean ± SD) from six mice of each genotype.
Mentions: We analyzed intrathymic development in γc− mice to better define the nature of any developmental blocks resulting from the absence of γc. When comparing absolute numbers of CD4−CD8− double negative (DN) cells, CD4+CD8+ double positive (DP) cells, and CD4+CD8− and CD4−CD8+ single positive (SP) mature T cells, the DN and CD8 SP populations were more affected by the absence of γc (Fig. 1 A). While both DP and CD4 SP cells were reduced by 15–20-fold (similar to the overall decrease in thymic cellularity), the DN and CD8 SP subsets were reduced almost 40-fold. The DN compartment contains both early thymocyte precursors (CD3−) as well as mature CD3+ TCR-γ/δ and TCR-α/β cells. While γ/δ T cells do not develop in γc− mice (4, 28), DN α/β T cells are present (32). To specifically evaluate γc− TCR− thymocyte progenitors, we studied CD44 and CD25 expression on CD3−CD4−CD8− (TN) thymocytes by four-color immunofluorescence analysis. Previous studies have demonstrated that these cells differentiate through the following stages: CD44+CD25− → CD44+CD25+ → CD44−CD25+ → CD44−CD25− (33; for a review, see reference 34).

Bottom Line: Interleukin (IL)-7 interactions with its cognate receptor complex (IL-7Ralpha coupled to the common cytokine receptor gamma chain, gammac) play a dominant role in early thymopoiesis.We demonstrate that gammac-dependent cytokines do not appear to be required for normal pre-TCR function, and that the rate-limiting step in alpha/beta T cell development in gammac- mice does not involve TCR-beta chain rearrangements, but rather results from poor maintenance of early thymocytes.Thus, a series of overlapping signals derived from cytokine and T cell receptors guide the process of alpha/beta thymocyte development.

View Article: PubMed Central - PubMed

Affiliation: Institut National de la Santé et de la Recherche Médicale (INSERM) U429, Hôpital Necker-Enfants Malades, F-75743 Paris, France. disanto@nexker.fr

ABSTRACT
Intracellular signals emanating from cytokine and antigen receptors are integrated during the process of intrathymic development. Still, the relative contributions of cytokine receptor signaling to pre-T cell receptor (TCR) and TCR-mediated differentiation remain undefined. Interleukin (IL)-7 interactions with its cognate receptor complex (IL-7Ralpha coupled to the common cytokine receptor gamma chain, gammac) play a dominant role in early thymopoiesis. However, alpha/beta T cell development in IL-7-, IL-7Ralpha-, and gammac-deficient mice is only partially compromised, suggesting that additional pathways can rescue alpha/beta T lineage cells in these mice. We have investigated the potential interdependence of gammac- and pre-TCR-dependent pathways during intrathymic alpha/beta T cell differentiation. We demonstrate that gammac-dependent cytokines do not appear to be required for normal pre-TCR function, and that the rate-limiting step in alpha/beta T cell development in gammac- mice does not involve TCR-beta chain rearrangements, but rather results from poor maintenance of early thymocytes. Moreover, mice double mutant for both gammac and pre-Talpha show vastly reduced thymic cellularity and a complete arrest of thymocyte differentiation at the CD44(+)CD25(+) cell stage. These observations demonstrate that the pre-TCR provides the gammac-independent signal which allows alpha/beta T cell development in gammac- mice. Thus, a series of overlapping signals derived from cytokine and T cell receptors guide the process of alpha/beta thymocyte development.

Show MeSH
Related in: MedlinePlus