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Expression of the transcription factor cKrox in peripheral CD8 T cells reveals substantial postthymic plasticity in CD4-CD8 lineage differentiation.

Jenkinson SR, Intlekofer AM, Sun G, Feigenbaum L, Reiner SL, Bosselut R - J. Exp. Med. (2007)

Bottom Line: It is, however, unclear whether the CD4-CD8 differentiation of postthymic T cells retains some level of plasticity or is stably maintained by mechanisms distinct from those that set lineage choice in the thymus.To address this issue, we examined if coreceptor or effector gene expression in mature CD8 T cells remains sensitive to the zinc finger transcription factor cKrox, which promotes CD4 and inhibits CD8 differentiation when expressed in thymocytes.These observations reveal a persistent degree of plasticity in CD4-CD8 differentiation in mature T cells.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Immune Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.

ABSTRACT
Most T cells belong to either of two lineages defined by the mutually exclusive expression of CD4 and CD8 coreceptors: CD4 T cells are major histocompatibility complex (MHC) II restricted and have helper function, whereas CD8 T cells are MHC I restricted and have cytotoxic function. The divergence between these two lineages occurs during intrathymic selection and is thought to be irreversible in mature T cells. It is, however, unclear whether the CD4-CD8 differentiation of postthymic T cells retains some level of plasticity or is stably maintained by mechanisms distinct from those that set lineage choice in the thymus. To address this issue, we examined if coreceptor or effector gene expression in mature CD8 T cells remains sensitive to the zinc finger transcription factor cKrox, which promotes CD4 and inhibits CD8 differentiation when expressed in thymocytes. We show that cKrox transduction into CD8 T cells inhibits their expression of CD8 and cytotoxic effector genes and impairs their cytotoxic activity, and that it promotes expression of helper-specific genes, although not of CD4 itself. These observations reveal a persistent degree of plasticity in CD4-CD8 differentiation in mature T cells.

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cKrox-induced Eomes repression mediates in part its reduction of IFN-γ production. (A) cKrox represses Eomes but not T-bet expression. Sorted GFP+CD8+ cells were analyzed as in Fig. 2 A for Eomes and T-bet gene expression. (B) cKrox- or control-transduced CD4-depleted splenocytes were analyzed by flow cytometry for CD122 and CD127 surface expression. Two parameter dot plots are gated on all live cells. Numbers represent mean fluorescence intensity of CD122 or CD127 expression in GFP+ cells. Results are representative of three experiments. (C and D) CD4-depleted splenocytes were cotransduced with Eomes-NGFR and cKrox-GFP viruses. 3 d later, flow cytometric analysis of CD8, NGFR, and GFP expression distinguishes CD8 cells infected with either the Eomes or cKrox virus, with both viruses (both), and uninfected CD8 cells (none), as depicted in Fig. S4 A. (C) Analyses of IFN-γ production by intracellular cytokine staining are shown as single-parameter histograms gated on each population. Numbers represent the percent of cells producing IFN-γ. (D) Perforin gene expression was analyzed by RT-PCR on sorted cells from each population and is expressed relative to uninfected cells (set to 1 arbitrarily). Results in each panel are representative of two separate transductions.
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fig3: cKrox-induced Eomes repression mediates in part its reduction of IFN-γ production. (A) cKrox represses Eomes but not T-bet expression. Sorted GFP+CD8+ cells were analyzed as in Fig. 2 A for Eomes and T-bet gene expression. (B) cKrox- or control-transduced CD4-depleted splenocytes were analyzed by flow cytometry for CD122 and CD127 surface expression. Two parameter dot plots are gated on all live cells. Numbers represent mean fluorescence intensity of CD122 or CD127 expression in GFP+ cells. Results are representative of three experiments. (C and D) CD4-depleted splenocytes were cotransduced with Eomes-NGFR and cKrox-GFP viruses. 3 d later, flow cytometric analysis of CD8, NGFR, and GFP expression distinguishes CD8 cells infected with either the Eomes or cKrox virus, with both viruses (both), and uninfected CD8 cells (none), as depicted in Fig. S4 A. (C) Analyses of IFN-γ production by intracellular cytokine staining are shown as single-parameter histograms gated on each population. Numbers represent the percent of cells producing IFN-γ. (D) Perforin gene expression was analyzed by RT-PCR on sorted cells from each population and is expressed relative to uninfected cells (set to 1 arbitrarily). Results in each panel are representative of two separate transductions.

Mentions: The inhibition by cKrox of IFN-γ production was unexpected, as CD4 T cells can differentiate into type 1 (Th1) effectors that produce IFN-γ. Two T-box transcription factors, eomesodermin (Eomes) and T-bet, control T cell expression of IFN-γ (14–16). Both factors are expressed in CD8 T cells, whereas T-bet is primarily responsible for Th1 CD4 T cell commitment (17). Thus, we considered the possibility that cKrox was impairing IFN-γ production in CD8 T cells by repressing Eomes. Indeed, cKrox transduction in CD8 T cells reduced Eomes mRNA levels to <25% of those in control-transduced cells but had essentially no effect on T-bet expression (Fig. 3 A). Furthermore, cKrox transduction reduced expression of IL-2Rβ (CD122), a target of Eomes in CD8 T cells (18) (Fig. 3 B). In contrast, cKrox did not affect expression of IL-7Rα (CD127), a receptor normally expressed on both CD4 and CD8 T cells (Fig. 3 B).


Expression of the transcription factor cKrox in peripheral CD8 T cells reveals substantial postthymic plasticity in CD4-CD8 lineage differentiation.

Jenkinson SR, Intlekofer AM, Sun G, Feigenbaum L, Reiner SL, Bosselut R - J. Exp. Med. (2007)

cKrox-induced Eomes repression mediates in part its reduction of IFN-γ production. (A) cKrox represses Eomes but not T-bet expression. Sorted GFP+CD8+ cells were analyzed as in Fig. 2 A for Eomes and T-bet gene expression. (B) cKrox- or control-transduced CD4-depleted splenocytes were analyzed by flow cytometry for CD122 and CD127 surface expression. Two parameter dot plots are gated on all live cells. Numbers represent mean fluorescence intensity of CD122 or CD127 expression in GFP+ cells. Results are representative of three experiments. (C and D) CD4-depleted splenocytes were cotransduced with Eomes-NGFR and cKrox-GFP viruses. 3 d later, flow cytometric analysis of CD8, NGFR, and GFP expression distinguishes CD8 cells infected with either the Eomes or cKrox virus, with both viruses (both), and uninfected CD8 cells (none), as depicted in Fig. S4 A. (C) Analyses of IFN-γ production by intracellular cytokine staining are shown as single-parameter histograms gated on each population. Numbers represent the percent of cells producing IFN-γ. (D) Perforin gene expression was analyzed by RT-PCR on sorted cells from each population and is expressed relative to uninfected cells (set to 1 arbitrarily). Results in each panel are representative of two separate transductions.
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Related In: Results  -  Collection

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fig3: cKrox-induced Eomes repression mediates in part its reduction of IFN-γ production. (A) cKrox represses Eomes but not T-bet expression. Sorted GFP+CD8+ cells were analyzed as in Fig. 2 A for Eomes and T-bet gene expression. (B) cKrox- or control-transduced CD4-depleted splenocytes were analyzed by flow cytometry for CD122 and CD127 surface expression. Two parameter dot plots are gated on all live cells. Numbers represent mean fluorescence intensity of CD122 or CD127 expression in GFP+ cells. Results are representative of three experiments. (C and D) CD4-depleted splenocytes were cotransduced with Eomes-NGFR and cKrox-GFP viruses. 3 d later, flow cytometric analysis of CD8, NGFR, and GFP expression distinguishes CD8 cells infected with either the Eomes or cKrox virus, with both viruses (both), and uninfected CD8 cells (none), as depicted in Fig. S4 A. (C) Analyses of IFN-γ production by intracellular cytokine staining are shown as single-parameter histograms gated on each population. Numbers represent the percent of cells producing IFN-γ. (D) Perforin gene expression was analyzed by RT-PCR on sorted cells from each population and is expressed relative to uninfected cells (set to 1 arbitrarily). Results in each panel are representative of two separate transductions.
Mentions: The inhibition by cKrox of IFN-γ production was unexpected, as CD4 T cells can differentiate into type 1 (Th1) effectors that produce IFN-γ. Two T-box transcription factors, eomesodermin (Eomes) and T-bet, control T cell expression of IFN-γ (14–16). Both factors are expressed in CD8 T cells, whereas T-bet is primarily responsible for Th1 CD4 T cell commitment (17). Thus, we considered the possibility that cKrox was impairing IFN-γ production in CD8 T cells by repressing Eomes. Indeed, cKrox transduction in CD8 T cells reduced Eomes mRNA levels to <25% of those in control-transduced cells but had essentially no effect on T-bet expression (Fig. 3 A). Furthermore, cKrox transduction reduced expression of IL-2Rβ (CD122), a target of Eomes in CD8 T cells (18) (Fig. 3 B). In contrast, cKrox did not affect expression of IL-7Rα (CD127), a receptor normally expressed on both CD4 and CD8 T cells (Fig. 3 B).

Bottom Line: It is, however, unclear whether the CD4-CD8 differentiation of postthymic T cells retains some level of plasticity or is stably maintained by mechanisms distinct from those that set lineage choice in the thymus.To address this issue, we examined if coreceptor or effector gene expression in mature CD8 T cells remains sensitive to the zinc finger transcription factor cKrox, which promotes CD4 and inhibits CD8 differentiation when expressed in thymocytes.These observations reveal a persistent degree of plasticity in CD4-CD8 differentiation in mature T cells.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Immune Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.

ABSTRACT
Most T cells belong to either of two lineages defined by the mutually exclusive expression of CD4 and CD8 coreceptors: CD4 T cells are major histocompatibility complex (MHC) II restricted and have helper function, whereas CD8 T cells are MHC I restricted and have cytotoxic function. The divergence between these two lineages occurs during intrathymic selection and is thought to be irreversible in mature T cells. It is, however, unclear whether the CD4-CD8 differentiation of postthymic T cells retains some level of plasticity or is stably maintained by mechanisms distinct from those that set lineage choice in the thymus. To address this issue, we examined if coreceptor or effector gene expression in mature CD8 T cells remains sensitive to the zinc finger transcription factor cKrox, which promotes CD4 and inhibits CD8 differentiation when expressed in thymocytes. We show that cKrox transduction into CD8 T cells inhibits their expression of CD8 and cytotoxic effector genes and impairs their cytotoxic activity, and that it promotes expression of helper-specific genes, although not of CD4 itself. These observations reveal a persistent degree of plasticity in CD4-CD8 differentiation in mature T cells.

Show MeSH
Related in: MedlinePlus