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An essential role for nuclear factor kappaB in promoting double positive thymocyte apoptosis.

Hettmann T, DiDonato J, Karin M, Leiden JM - J. Exp. Med. (1999)

Bottom Line: However, the numbers of peripheral CD8(+) T cells were significantly reduced in these animals.The mIkappaB-alpha thymocytes displayed a marked proliferative defect and significant reductions in interleukin (IL)-2, IL-3, and granulocyte/macrophage colony-stimulating factor production after cross-linking of the T cell antigen receptor.Apoptosis of wild-type DP thymocytes after in vivo administration of alpha-CD3 mAb was preceded by a significant reduction in the level of expression of the antiapoptotic gene, bcl-xL.

View Article: PubMed Central - PubMed

Affiliation: Departments of Medicine and Pathology, University of Chicago, Chicago, Illinois 60637, USA.

ABSTRACT
To examine the role of nuclear factor (NF)-kappaB in T cell development and activation in vivo, we produced transgenic mice that express a superinhibitory mutant form of inhibitor kappaB-alpha (IkappaB-alphaA32/36) under the control of the T cell-specific CD2 promoter and enhancer (mutant [m]IkappaB-alpha mice). Thymocyte development proceeded normally in the mIkappaB-alpha mice. However, the numbers of peripheral CD8(+) T cells were significantly reduced in these animals. The mIkappaB-alpha thymocytes displayed a marked proliferative defect and significant reductions in interleukin (IL)-2, IL-3, and granulocyte/macrophage colony-stimulating factor production after cross-linking of the T cell antigen receptor. Perhaps more unexpectedly, double positive (CD4(+)CD8(+); DP) thymocytes from the mIkappaB-alpha mice were resistant to alpha-CD3-mediated apoptosis in vivo. In contrast, they remained sensitive to apoptosis induced by gamma-irradiation. Apoptosis of wild-type DP thymocytes after in vivo administration of alpha-CD3 mAb was preceded by a significant reduction in the level of expression of the antiapoptotic gene, bcl-xL. In contrast, the DP mIkappaB-alpha thymocytes maintained high level expression of bcl-xL after alpha-CD3 treatment. Taken together, these results demonstrated important roles for NF-kappaB in both inducible cytokine expression and T cell proliferation after TCR engagement. In addition, NF-kappaB is required for the alpha-CD3-mediated apoptosis of DP thymocytes through a pathway that involves the regulation of the antiapoptotic gene, bcl-xL.

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Reduced cytokine  production by mIκB-α transgenic thymocytes. Cultured thymocytes from wild-type (white  bars) and transgenic IκB-αA32/36  mice (black bars) were stimulated  with immobilized α-CD3 plus  α-CD28 antibodies (16 μg/ml).  The levels of IL-2, GM-CSF,  and IL-3 in the culture supernatants were assayed by ELISA  48 h after stimulation.
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Figure 5: Reduced cytokine production by mIκB-α transgenic thymocytes. Cultured thymocytes from wild-type (white bars) and transgenic IκB-αA32/36 mice (black bars) were stimulated with immobilized α-CD3 plus α-CD28 antibodies (16 μg/ml). The levels of IL-2, GM-CSF, and IL-3 in the culture supernatants were assayed by ELISA 48 h after stimulation.

Mentions: Many cytokine genes including IL-2, IL-3, and GM-CSF are potential targets for NF-κB (60). However, the role of NF-κB in regulating activation-specific cytokine expression in vivo, particularly the expression of the IL-2 gene, remains controversial. Therefore, we compared cytokine production by the wild-type and mIκB-α thymocytes after activation with α-CD3 plus α-CD28 mAbs (Fig. 5). As compared with wild-type thymocytes, the mIκB-α thymocytes displayed significantly decreased production of IL-2, IL-3, and GM-CSF after α-CD3 plus α-CD28 activation (Fig. 5). IL-2 production was most significantly reduced (28% of wild-type levels), whereas GM-CSF and IL-3 production were less dramatically inhibited (Fig. 5). Taken together, these experiments demonstrated that NF-κB is required both for the induction of multiple cytokines and for normal thymocyte proliferation after TCR cross-linking.


An essential role for nuclear factor kappaB in promoting double positive thymocyte apoptosis.

Hettmann T, DiDonato J, Karin M, Leiden JM - J. Exp. Med. (1999)

Reduced cytokine  production by mIκB-α transgenic thymocytes. Cultured thymocytes from wild-type (white  bars) and transgenic IκB-αA32/36  mice (black bars) were stimulated  with immobilized α-CD3 plus  α-CD28 antibodies (16 μg/ml).  The levels of IL-2, GM-CSF,  and IL-3 in the culture supernatants were assayed by ELISA  48 h after stimulation.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC1887697&req=5

Figure 5: Reduced cytokine production by mIκB-α transgenic thymocytes. Cultured thymocytes from wild-type (white bars) and transgenic IκB-αA32/36 mice (black bars) were stimulated with immobilized α-CD3 plus α-CD28 antibodies (16 μg/ml). The levels of IL-2, GM-CSF, and IL-3 in the culture supernatants were assayed by ELISA 48 h after stimulation.
Mentions: Many cytokine genes including IL-2, IL-3, and GM-CSF are potential targets for NF-κB (60). However, the role of NF-κB in regulating activation-specific cytokine expression in vivo, particularly the expression of the IL-2 gene, remains controversial. Therefore, we compared cytokine production by the wild-type and mIκB-α thymocytes after activation with α-CD3 plus α-CD28 mAbs (Fig. 5). As compared with wild-type thymocytes, the mIκB-α thymocytes displayed significantly decreased production of IL-2, IL-3, and GM-CSF after α-CD3 plus α-CD28 activation (Fig. 5). IL-2 production was most significantly reduced (28% of wild-type levels), whereas GM-CSF and IL-3 production were less dramatically inhibited (Fig. 5). Taken together, these experiments demonstrated that NF-κB is required both for the induction of multiple cytokines and for normal thymocyte proliferation after TCR cross-linking.

Bottom Line: However, the numbers of peripheral CD8(+) T cells were significantly reduced in these animals.The mIkappaB-alpha thymocytes displayed a marked proliferative defect and significant reductions in interleukin (IL)-2, IL-3, and granulocyte/macrophage colony-stimulating factor production after cross-linking of the T cell antigen receptor.Apoptosis of wild-type DP thymocytes after in vivo administration of alpha-CD3 mAb was preceded by a significant reduction in the level of expression of the antiapoptotic gene, bcl-xL.

View Article: PubMed Central - PubMed

Affiliation: Departments of Medicine and Pathology, University of Chicago, Chicago, Illinois 60637, USA.

ABSTRACT
To examine the role of nuclear factor (NF)-kappaB in T cell development and activation in vivo, we produced transgenic mice that express a superinhibitory mutant form of inhibitor kappaB-alpha (IkappaB-alphaA32/36) under the control of the T cell-specific CD2 promoter and enhancer (mutant [m]IkappaB-alpha mice). Thymocyte development proceeded normally in the mIkappaB-alpha mice. However, the numbers of peripheral CD8(+) T cells were significantly reduced in these animals. The mIkappaB-alpha thymocytes displayed a marked proliferative defect and significant reductions in interleukin (IL)-2, IL-3, and granulocyte/macrophage colony-stimulating factor production after cross-linking of the T cell antigen receptor. Perhaps more unexpectedly, double positive (CD4(+)CD8(+); DP) thymocytes from the mIkappaB-alpha mice were resistant to alpha-CD3-mediated apoptosis in vivo. In contrast, they remained sensitive to apoptosis induced by gamma-irradiation. Apoptosis of wild-type DP thymocytes after in vivo administration of alpha-CD3 mAb was preceded by a significant reduction in the level of expression of the antiapoptotic gene, bcl-xL. In contrast, the DP mIkappaB-alpha thymocytes maintained high level expression of bcl-xL after alpha-CD3 treatment. Taken together, these results demonstrated important roles for NF-kappaB in both inducible cytokine expression and T cell proliferation after TCR engagement. In addition, NF-kappaB is required for the alpha-CD3-mediated apoptosis of DP thymocytes through a pathway that involves the regulation of the antiapoptotic gene, bcl-xL.

Show MeSH
Related in: MedlinePlus