Research ArticleImmunology

IL-2Rβ abundance differentially tunes IL-2 signaling dynamics in CD4+ and CD8+ T cells

See allHide authors and affiliations

Science Signaling  19 Dec 2017:
Vol. 10, Issue 510, eaan4931
DOI: 10.1126/scisignal.aan4931
  • Fig. 1 Proliferative responses of CD4 and CD8 T cells to IL-2.

    (A) S phase entry of rested CD4+ and CD8+ T cell blasts was assessed with a 1-hour pulse of 5-ethynyl-2′-deoxyuridine (EdU) after the indicated duration of interleukin-2 (IL-2) stimulation. (B) Cell proliferation after 72 hours of IL-2 stimulation was assessed by dye dilution (CellTrace Violet) compared to undivided cells sustained with low-dose IL-7. Pooled results from seven independent experiments plotted as means ± SEM (A) or representative of three independent experiments (B). Time course (A) compared by repeated-measures analysis of variance (ANOVA) (cell type, time, and interaction, all P < 0.0001) with Bonferroni multiple comparison test (significant P < 0.05: **P < 0.01, ***P < 0.001 for CD4s versus CD8s at a given time point).

  • Fig. 2 Distinct IL-2 signaling dynamics in CD4 and CD8 T cells.

    (A) Rested CD4+ and CD8+ T cell blasts were stimulated with a fourfold titration of IL-2 from 1000 to 0.001 U/ml, and phosphorylated signal transducer and activator of transcription 5 (pSTAT5) was assessed by phosphoflow cytometry. (B) Fraction of responding (pSTAT5+) cells at each concentration of IL-2. EC50 (median effective concentration) CD4 0.35 U/ml [95% confidence interval (CI), 0.29 to 0.42]; EC50 CD8 0.28 U/ml (95% CI, 0.24 to 0.32). (C) Time course of pSTAT5 accumulation in CD4+ and CD8+ T cells after IL-2 stimulation. (D) Quantification of pSTAT5 over time (cell type, time, and interaction, all P < 0.0001). (E) Myc protein accumulation in CD4+ and CD8+ T cells. (F) Quantification of Myc over the first 2 hours of IL-2 stimulation [cell type, P < 0.0001; time, P = 0.045; interaction, not significant (n.s.)]. Representative histograms from 3 (A), 11 (C), or 4 (E) independent experiments. Plotted as mean ± SEM of 3 (B) or 4 (F) independent experiments or mean with 95% CI from 11 independent experiments (D). Time courses compared by repeated-measures ANOVA with Bonferroni multiple comparison test (significant P < 0.05, *P < 0.05: **P < 0.01, ***P < 0.001 for CD4s versus CD8s at a given time point).

  • Fig. 3 Requirements for sustained IL-2 signaling.

    (A) Cells were stimulated for 30 min, and then IL-2 was washed out and pSTAT5 was monitored by phosphoflow cytometry. (B) Quantification of washout. (C and D) Cells were stimulated with IL-2, with a pharmacological inhibitor of JAK3 (JAK3i) added at t = 15 min, and signal decay was monitored (C) and quantified (D). (E and F) Cells were stimulated simultaneously with IL-2 and brefeldin A as pSTAT5 was monitored over time (E) and quantified (F). Cell type, time, and interaction, all P < 0.0001. (G and H) Cells were stimulated simultaneously with IL-2 and cycloheximide as pSTAT5 was monitored over time (G) and quantified (H). In all experiments, cell type, time, and interaction, all P < 0.0001. Data are representative of three independent experiments (A, C, E, and G) or plotted as means ± SEM of three independent experiments (B, D, F, and H). Time courses compared by repeated-measures ANOVA with Bonferroni multiple comparison test (significant P < 0.05: **P < 0.01, ***P < 0.001 for CD4s versus CD8s at a given time point).

  • Fig. 4 IL-2R subunit abundance.

    (A) Representative histograms of IL-2Rα, IL-2Rβ, and IL-2Rγ staining on the surface of CD4+ and CD8+ T cells. (B) Quantification of receptor abundance relative to mean fluorescence intensity (MFI) on CD4+ T cells in each experiment. (C) Representative histograms of IL-2Rα, IL-2Rβ, and IL-2Rγ intracellular staining in CD4+ and CD8+ T cells. (D) Quantification of intracellular receptor abundance relative to MFI on CD4+ T cells in each experiment. (E) Quantification of il2ra, il2rb, and il2rg transcripts in resting CD4+ and CD8+ T cell blasts by qPCR. Data are representative of seven (A) and three (C) independent experiments. Pooled data from seven (B) and three (D) independent experiments, plotted ± SEM. Paired t test: *P < 0.05, **P < 0.01, ***P < 0.001. (E) mRNA from three biological replicates plotted with 95% CI.

  • Fig. 5 Comparative dynamics of IL-7 and IL-15.

    (A) Schematic of IL-2, IL-7, and IL-15 receptor components. Note that IL-15 is typically presented in trans from IL-15Rα on a neighboring cell. (B) Representative time course histograms of pSTAT5 in CD4+ T cells stimulated with IL-7 or IL-15. (C) Fraction of pSTAT5+ cells in response to IL-7 and IL-15. Cytokine, time, and interaction, all P < 0.0001. (D) Representative time course histograms of pSTAT5 in CD8+ T cells stimulated with IL-7 or IL-15. (E) Quantification of pSTAT5 in response to IL-7 or IL-15. Cytokine, n.s.; time, P < 0.0001; interaction, P = 0.0004. Data are representative of (B and D) or pooled from (C and E) three independent experiments. Plotted ± SEM in (C) and (E). Time courses compared by repeated-measures ANOVA with Bonferroni multiple comparison test (significant P < 0.05: **P < 0.01, ***P < 0.001 for IL-7 versus IL-15 at a given time point).

  • Fig. 6 Knockdown of IL2RB in CD8 T cell blasts.

    (A) Effect of expressing four different shRNAs targeting IL2RB relative to scrambled shRNA on surface IL-2Rβ abundance in CD8+ T cells, as assessed by fluorescence-activated cell sorting (FACS). (B) pSTAT5 over time in IL-2–treated CD8+ T cells expressing the scrambled IL2RB shRNA or IL2RB shRNA #2. (C) Fraction of pSTAT5+ cells over time. [Repeated-measures ANOVA: shRNA, P < 0.0001; time, P < 0.0001; interaction, P = 0.0097. Bonferroni posttest of scramble shRNA versus shRNA #1: 0.25 to 3 hours (P < 0.001); versus shRNA #2: 0.75 and 1 hour (P < 0.001); versus shRNA #3: 0.75 hour (P < 0.05), 1 hour (P < 0.001); all other comparisons to scramble (n.s.).] (D) S phase entry, assessed by EdU incorporation, after 13 hours of IL-2 stimulation in briefly rested CD8+ T cell blasts expressing the indicated shRNAs (GFP+) or untransduced (GFP) cells. ***P < 0.001 by one-way ANOVA with Bonferroni multiple comparison test relative to scramble shRNA. Data are representative of (B) or pooled from four (A) or three (B to D) independent experiments. Plotted as means ± SEM.

  • Fig. 7 Treg IL-2Rβ abundance and IL-2 signaling dynamics.

    (A) Representative intracellular staining for IL-2Rβ in CD4+ T cell blasts, CD4+Foxp3+ Tregs, and CD8+ T cell blasts. (B) Quantification of IL-2Rβ abundance relative to CD4+ T cell blasts. (C) Representative histograms of STAT5 phosphorylation over time after IL-2 stimulation of CD4+Foxp3+ Tregs in freshly isolated splenocytes, quantified in (D). All graphs plotted as mean ± SEM. In (B), Tregs are from four separate mice, and blasts are from four separate preparations. ***P < 0.001 by one-way ANOVA with Bonferroni multiple comparison test. In (D), data are pooled from five mice.

Supplementary Materials

  • Supplementary Materials for:

    IL-2Rβ abundance differentially tunes IL-2 signaling dynamics in CD4+ and CD8+ T cells

    Geoffrey A. Smith, Jack Taunton, Arthur Weiss*

    *Corresponding author. Email: arthur.weiss{at}ucsf.edu

    This PDF file includes:

    • Fig. S1. STAT5 phosphorylation in IL-2–stimulated CD4+ and CD8+ T cells.
    • Fig. S2. PI3K-mTOR signaling in IL-2–stimulated CD4+ and CD8+ T cells.
    • Fig. S3. IL2RB shRNAs.
    • Table S1. FACS antibodies.
    • Table S2. qPCR assays.
    • Table S3. IL2RB shRNAs.

    [Download PDF]

    Technical Details

    Format: Adobe Acrobat PDF

    Size: 1.11 MB


    Citation: G. A. Smith, J. Taunton, A. Weiss, IL-2Rβ abundance differentially tunes IL-2 signaling dynamics in CD4+ and CD8+ T cells. Sci. Signal. 10, eaan4931 (2017).

    © 2017 American Association for the Advancement of Science

Navigate This Article