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Impact of the TCR signal on regulatory T cell homeostasis, function, and trafficking.

Kim JK, Klinger M, Benjamin J, Xiao Y, Erle DJ, Littman DR, Killeen N - PLoS ONE (2009)

Bottom Line: Using an Ox40-cre allele that is prominently expressed in Treg cells, and a conditional allele of the gene encoding p56(Lck), we have examined the importance of TCR signaling in Treg cells.Inactivation of p56(Lck) resulted in abnormal Treg homeostasis characterized by impaired turnover, preferential redistribution to the lymph nodes, loss of suppressive function, and striking changes in gene expression.Abnormal Treg cell homeostasis and function did not reflect the involvement of p56(Lck) in CD4 function because these effects were not observed when CD4 expression was inactivated by Ox40-cre.The results make clear multiple aspects of Treg cell homeostasis and phenotype that are dependent on a sustained capacity to signal through the TCR.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology and Immunology, University of California San Francisco, San Francisco, CA, USA.

ABSTRACT
Signaling through the T cell antigen receptor (TCR) is important for the homeostasis of naïve and memory CD4(+) T cells. The significance of TCR signaling in regulatory T (Treg) cells has not been systematically addressed. Using an Ox40-cre allele that is prominently expressed in Treg cells, and a conditional allele of the gene encoding p56(Lck), we have examined the importance of TCR signaling in Treg cells. Inactivation of p56(Lck) resulted in abnormal Treg homeostasis characterized by impaired turnover, preferential redistribution to the lymph nodes, loss of suppressive function, and striking changes in gene expression. Abnormal Treg cell homeostasis and function did not reflect the involvement of p56(Lck) in CD4 function because these effects were not observed when CD4 expression was inactivated by Ox40-cre.The results make clear multiple aspects of Treg cell homeostasis and phenotype that are dependent on a sustained capacity to signal through the TCR.

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Ox40-cre-mediated inactivation of p56Lck in T cells.A. Selective inactivation of p56Lck in CD4+ T cells in lymph nodes of Ox40-cre mice carrying a conditional  allele of the Lck gene. The histograms show intracellular p56Lck detected with the 1F6 monoclonal antibody in B cells, CD4+ and CD8+ T cells in mice of the indicated genotypes. B. Intracellular p56Lck (as in A.) in T cells of the indicated phenotypes (regulatory, memory and naïve) from Lck/Fyn mice. C. Increased frequency of Treg cells that had not undergone Ox40-cre-mediated recombination in mice carrying the conditional  Lck allele compared to mice carrying the ROSA26-YFP allele. The graph shows the frequencies of YFP− or p56Lck-positive (1F6+) CD25+ Treg cells in individual mice of the indicated genotypes.
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pone-0006580-g002: Ox40-cre-mediated inactivation of p56Lck in T cells.A. Selective inactivation of p56Lck in CD4+ T cells in lymph nodes of Ox40-cre mice carrying a conditional allele of the Lck gene. The histograms show intracellular p56Lck detected with the 1F6 monoclonal antibody in B cells, CD4+ and CD8+ T cells in mice of the indicated genotypes. B. Intracellular p56Lck (as in A.) in T cells of the indicated phenotypes (regulatory, memory and naïve) from Lck/Fyn mice. C. Increased frequency of Treg cells that had not undergone Ox40-cre-mediated recombination in mice carrying the conditional Lck allele compared to mice carrying the ROSA26-YFP allele. The graph shows the frequencies of YFP− or p56Lck-positive (1F6+) CD25+ Treg cells in individual mice of the indicated genotypes.

Mentions: Ox40-cre-dependent loss of p56Lck expression could be visualized by intracellular flow cytometry using the 1F6 p56Lck-specific monoclonal antibody (Figure 2). Whereas CD4+ T cells from control or Fyn mice showed equivalent staining with this antibody, there was selective loss of immunoreactivity in CD4+ T cells from Lck or Lck/Fyn mice (Figure 2A). Inactivation of p56Lck could be detected in a small fraction of phenotypically naïve CD4+ T cells, a larger fraction of memory-phenotype CD4+ T cells, and the majority of FoxP3+ T cells (Figure 2B). These observations were largely consistent with the expected pattern of expression of Ox40-cre based on the analysis of mice carrying the YFP reporter (Figure 1 and data not shown). We noted, however, that the frequency of Treg cells that retained wild-type p56Lck was two-to-four-fold higher than the YFP analysis predicted in the lymph nodes and spleen respectively (Figure 2C). This disparity raised the possibility that Treg cell homeostasis was disturbed by inactivation of p56Lck.


Impact of the TCR signal on regulatory T cell homeostasis, function, and trafficking.

Kim JK, Klinger M, Benjamin J, Xiao Y, Erle DJ, Littman DR, Killeen N - PLoS ONE (2009)

Ox40-cre-mediated inactivation of p56Lck in T cells.A. Selective inactivation of p56Lck in CD4+ T cells in lymph nodes of Ox40-cre mice carrying a conditional  allele of the Lck gene. The histograms show intracellular p56Lck detected with the 1F6 monoclonal antibody in B cells, CD4+ and CD8+ T cells in mice of the indicated genotypes. B. Intracellular p56Lck (as in A.) in T cells of the indicated phenotypes (regulatory, memory and naïve) from Lck/Fyn mice. C. Increased frequency of Treg cells that had not undergone Ox40-cre-mediated recombination in mice carrying the conditional  Lck allele compared to mice carrying the ROSA26-YFP allele. The graph shows the frequencies of YFP− or p56Lck-positive (1F6+) CD25+ Treg cells in individual mice of the indicated genotypes.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2719063&req=5

pone-0006580-g002: Ox40-cre-mediated inactivation of p56Lck in T cells.A. Selective inactivation of p56Lck in CD4+ T cells in lymph nodes of Ox40-cre mice carrying a conditional allele of the Lck gene. The histograms show intracellular p56Lck detected with the 1F6 monoclonal antibody in B cells, CD4+ and CD8+ T cells in mice of the indicated genotypes. B. Intracellular p56Lck (as in A.) in T cells of the indicated phenotypes (regulatory, memory and naïve) from Lck/Fyn mice. C. Increased frequency of Treg cells that had not undergone Ox40-cre-mediated recombination in mice carrying the conditional Lck allele compared to mice carrying the ROSA26-YFP allele. The graph shows the frequencies of YFP− or p56Lck-positive (1F6+) CD25+ Treg cells in individual mice of the indicated genotypes.
Mentions: Ox40-cre-dependent loss of p56Lck expression could be visualized by intracellular flow cytometry using the 1F6 p56Lck-specific monoclonal antibody (Figure 2). Whereas CD4+ T cells from control or Fyn mice showed equivalent staining with this antibody, there was selective loss of immunoreactivity in CD4+ T cells from Lck or Lck/Fyn mice (Figure 2A). Inactivation of p56Lck could be detected in a small fraction of phenotypically naïve CD4+ T cells, a larger fraction of memory-phenotype CD4+ T cells, and the majority of FoxP3+ T cells (Figure 2B). These observations were largely consistent with the expected pattern of expression of Ox40-cre based on the analysis of mice carrying the YFP reporter (Figure 1 and data not shown). We noted, however, that the frequency of Treg cells that retained wild-type p56Lck was two-to-four-fold higher than the YFP analysis predicted in the lymph nodes and spleen respectively (Figure 2C). This disparity raised the possibility that Treg cell homeostasis was disturbed by inactivation of p56Lck.

Bottom Line: Using an Ox40-cre allele that is prominently expressed in Treg cells, and a conditional allele of the gene encoding p56(Lck), we have examined the importance of TCR signaling in Treg cells.Inactivation of p56(Lck) resulted in abnormal Treg homeostasis characterized by impaired turnover, preferential redistribution to the lymph nodes, loss of suppressive function, and striking changes in gene expression.Abnormal Treg cell homeostasis and function did not reflect the involvement of p56(Lck) in CD4 function because these effects were not observed when CD4 expression was inactivated by Ox40-cre.The results make clear multiple aspects of Treg cell homeostasis and phenotype that are dependent on a sustained capacity to signal through the TCR.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology and Immunology, University of California San Francisco, San Francisco, CA, USA.

ABSTRACT
Signaling through the T cell antigen receptor (TCR) is important for the homeostasis of naïve and memory CD4(+) T cells. The significance of TCR signaling in regulatory T (Treg) cells has not been systematically addressed. Using an Ox40-cre allele that is prominently expressed in Treg cells, and a conditional allele of the gene encoding p56(Lck), we have examined the importance of TCR signaling in Treg cells. Inactivation of p56(Lck) resulted in abnormal Treg homeostasis characterized by impaired turnover, preferential redistribution to the lymph nodes, loss of suppressive function, and striking changes in gene expression. Abnormal Treg cell homeostasis and function did not reflect the involvement of p56(Lck) in CD4 function because these effects were not observed when CD4 expression was inactivated by Ox40-cre.The results make clear multiple aspects of Treg cell homeostasis and phenotype that are dependent on a sustained capacity to signal through the TCR.

Show MeSH