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Crucial role of Jak3 in negative selection of self-reactive T cells.

Saijo K, Park SY, Ishida Y, Arase H, Saito T - J. Exp. Med. (1997)

Bottom Line: In spite of the severely reduced number of lymphocytes in Jak3-deficient mice, the differentiation profile of thymocytes was normal and mature T cells accumulated in the periphery with age.All peripheral T cells were in the activation state and thus were unable to be activated further, as demonstrated by the failure of eliciting Ca2+ response upon T cell receptor (TCR) stimulation.These findings demonstrate a crucial function of Jak3 in the negative selection of autoreactive T cells and the maintenance of functional peripheral T cells.

View Article: PubMed Central - PubMed

Affiliation: Center for Biomedical Science, Chiba University School of Medicine, Inohana, Chuo-ku, Japan.

ABSTRACT
Jak3 mediates growth signals through cytokine receptors such as interleukin-2 (IL-2), IL-4, and IL-7, and its deficiency results in autosomal recessive SCID in mice and humans. In spite of the severely reduced number of lymphocytes in Jak3-deficient mice, the differentiation profile of thymocytes was normal and mature T cells accumulated in the periphery with age. However, we found that self-reactive T cells were not deleted in the thymus and the peripheral tissues in Jak3-deficient mice. All peripheral T cells were in the activation state and thus were unable to be activated further, as demonstrated by the failure of eliciting Ca2+ response upon T cell receptor (TCR) stimulation. From the analysis of TCR-transgenic Jak3-deficient mice, only self-reactive T cells appeared to be in the activated state and anergic. These findings demonstrate a crucial function of Jak3 in the negative selection of autoreactive T cells and the maintenance of functional peripheral T cells.

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Functional analysis  of thymocytes and splenic T cells  from Jak3-deficient mice. (A)  Proliferation of splenic T cells  upon mitogenic stimulation.  Splenocytes (2 × 105) from Jak3  homozygous (−/−), heterozygous (+/−) mutant mice, and  wild-type littermates (+/+)  were stimulated with anti-CD3ε  mAb (145-2C11, 10 μg/ml),  Con A (2.5 μg/ml), IL-2 (40 U/ ml), Staphyloccocal enterotoxin  B (10 μg/ml), and the combination of PMA (5 ng/ml) and  A23187 (100 ng/ml). Cells were  cultured for 48 h and pulsed  with [3H]thymidine for 8 h. (B)  IL-2 production of thymocytes  and splenic T cells upon mitogenic stimulation. Thymocytes  and splenic T cells from Jak3homozygous (−/−), and heterozygous (+/−) mutant mice,  and wild-type littermates (+/+)  were stimulated with 145-2C11,  Con A, and PMA plus A23187  as described in (A). All results  were presented as mean ± SD  from triplicate cultures.
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Figure 3: Functional analysis of thymocytes and splenic T cells from Jak3-deficient mice. (A) Proliferation of splenic T cells upon mitogenic stimulation. Splenocytes (2 × 105) from Jak3 homozygous (−/−), heterozygous (+/−) mutant mice, and wild-type littermates (+/+) were stimulated with anti-CD3ε mAb (145-2C11, 10 μg/ml), Con A (2.5 μg/ml), IL-2 (40 U/ ml), Staphyloccocal enterotoxin B (10 μg/ml), and the combination of PMA (5 ng/ml) and A23187 (100 ng/ml). Cells were cultured for 48 h and pulsed with [3H]thymidine for 8 h. (B) IL-2 production of thymocytes and splenic T cells upon mitogenic stimulation. Thymocytes and splenic T cells from Jak3homozygous (−/−), and heterozygous (+/−) mutant mice, and wild-type littermates (+/+) were stimulated with 145-2C11, Con A, and PMA plus A23187 as described in (A). All results were presented as mean ± SD from triplicate cultures.

Mentions: Since splenic T cells in Jak3−/− mice are in the activated state, we asked whether these T cells might be functionally unresponsive to further stimulation. Indeed, splenic T cells from Jak3−/− mice failed to proliferate upon stimulation with either Con A or anti-CD3ε mAb crosslinking, regardless of the presence of exogenous IL-2. Furthermore, these T cells did not proliferate even after stimulation with PMA and Ca2+ ionophore (Fig. 3 A). In contrast with the splenic T cells, thymocytes from Jak3−/− mice responded to both anti-CD3ε cross-linking and stimulation with PMA plus Ca2+ ionophore (15). As shown in Fig. 3 B, thymocytes from Jak3−/− mice secreted a considerable amount of IL-2 compared with normal thymocytes, while splenic T cells from Jak3−/− mice produced very little. Cell surface staining revealed no difference in TCR expression between Jak3−/− and wild-type mice (15). These data demonstrated that splenic T cells in Jak3−/− mice possess defects in the signal transduction pathway leading to IL-2 production upon TCR stimulation, in addition to growth signal defects.


Crucial role of Jak3 in negative selection of self-reactive T cells.

Saijo K, Park SY, Ishida Y, Arase H, Saito T - J. Exp. Med. (1997)

Functional analysis  of thymocytes and splenic T cells  from Jak3-deficient mice. (A)  Proliferation of splenic T cells  upon mitogenic stimulation.  Splenocytes (2 × 105) from Jak3  homozygous (−/−), heterozygous (+/−) mutant mice, and  wild-type littermates (+/+)  were stimulated with anti-CD3ε  mAb (145-2C11, 10 μg/ml),  Con A (2.5 μg/ml), IL-2 (40 U/ ml), Staphyloccocal enterotoxin  B (10 μg/ml), and the combination of PMA (5 ng/ml) and  A23187 (100 ng/ml). Cells were  cultured for 48 h and pulsed  with [3H]thymidine for 8 h. (B)  IL-2 production of thymocytes  and splenic T cells upon mitogenic stimulation. Thymocytes  and splenic T cells from Jak3homozygous (−/−), and heterozygous (+/−) mutant mice,  and wild-type littermates (+/+)  were stimulated with 145-2C11,  Con A, and PMA plus A23187  as described in (A). All results  were presented as mean ± SD  from triplicate cultures.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2196119&req=5

Figure 3: Functional analysis of thymocytes and splenic T cells from Jak3-deficient mice. (A) Proliferation of splenic T cells upon mitogenic stimulation. Splenocytes (2 × 105) from Jak3 homozygous (−/−), heterozygous (+/−) mutant mice, and wild-type littermates (+/+) were stimulated with anti-CD3ε mAb (145-2C11, 10 μg/ml), Con A (2.5 μg/ml), IL-2 (40 U/ ml), Staphyloccocal enterotoxin B (10 μg/ml), and the combination of PMA (5 ng/ml) and A23187 (100 ng/ml). Cells were cultured for 48 h and pulsed with [3H]thymidine for 8 h. (B) IL-2 production of thymocytes and splenic T cells upon mitogenic stimulation. Thymocytes and splenic T cells from Jak3homozygous (−/−), and heterozygous (+/−) mutant mice, and wild-type littermates (+/+) were stimulated with 145-2C11, Con A, and PMA plus A23187 as described in (A). All results were presented as mean ± SD from triplicate cultures.
Mentions: Since splenic T cells in Jak3−/− mice are in the activated state, we asked whether these T cells might be functionally unresponsive to further stimulation. Indeed, splenic T cells from Jak3−/− mice failed to proliferate upon stimulation with either Con A or anti-CD3ε mAb crosslinking, regardless of the presence of exogenous IL-2. Furthermore, these T cells did not proliferate even after stimulation with PMA and Ca2+ ionophore (Fig. 3 A). In contrast with the splenic T cells, thymocytes from Jak3−/− mice responded to both anti-CD3ε cross-linking and stimulation with PMA plus Ca2+ ionophore (15). As shown in Fig. 3 B, thymocytes from Jak3−/− mice secreted a considerable amount of IL-2 compared with normal thymocytes, while splenic T cells from Jak3−/− mice produced very little. Cell surface staining revealed no difference in TCR expression between Jak3−/− and wild-type mice (15). These data demonstrated that splenic T cells in Jak3−/− mice possess defects in the signal transduction pathway leading to IL-2 production upon TCR stimulation, in addition to growth signal defects.

Bottom Line: In spite of the severely reduced number of lymphocytes in Jak3-deficient mice, the differentiation profile of thymocytes was normal and mature T cells accumulated in the periphery with age.All peripheral T cells were in the activation state and thus were unable to be activated further, as demonstrated by the failure of eliciting Ca2+ response upon T cell receptor (TCR) stimulation.These findings demonstrate a crucial function of Jak3 in the negative selection of autoreactive T cells and the maintenance of functional peripheral T cells.

View Article: PubMed Central - PubMed

Affiliation: Center for Biomedical Science, Chiba University School of Medicine, Inohana, Chuo-ku, Japan.

ABSTRACT
Jak3 mediates growth signals through cytokine receptors such as interleukin-2 (IL-2), IL-4, and IL-7, and its deficiency results in autosomal recessive SCID in mice and humans. In spite of the severely reduced number of lymphocytes in Jak3-deficient mice, the differentiation profile of thymocytes was normal and mature T cells accumulated in the periphery with age. However, we found that self-reactive T cells were not deleted in the thymus and the peripheral tissues in Jak3-deficient mice. All peripheral T cells were in the activation state and thus were unable to be activated further, as demonstrated by the failure of eliciting Ca2+ response upon T cell receptor (TCR) stimulation. From the analysis of TCR-transgenic Jak3-deficient mice, only self-reactive T cells appeared to be in the activated state and anergic. These findings demonstrate a crucial function of Jak3 in the negative selection of autoreactive T cells and the maintenance of functional peripheral T cells.

Show MeSH
Related in: MedlinePlus