Figure 6. SOCS3 is elevated and contributes to paralyzed phenotype of CD4⁺ T cells during strong immune stimulation.

(A) Microarray showing clustering of genes differentially expressed in naïve CD4 and CD8⁺ T cells in all T cell populations. (B) Naïve and memory CD4 and CD8⁺ T cell populations were sorted from splenocytes of control or immunotherapy treated mice and fold change in SOCS3 gene expression was quantified by qPCR. Expression of SOCS3 in flow cytometry-sorted naïve CD4⁺ T cells from (C) immunotherapy or (D) LPS treated mice at indicated time points. Naïve T cells were purified from (E) human PBMCs or (F) murine splenocytes using magnetic bead separation and incubated with high dose rhIL-2. At indicated time points, Socs3 expression was quantified by qPCR (bars) and ELISA (red lines). (G) Magnet purified murine, naïve CD4⁺ T cells were transfected with scrambled GFP tagged siRNA or Socs3 siRNA, incubated in high dose IL-2, and subjected to MLR (1:1). (H) Purified naïve CD4⁺ T cells from control or immunotherapy treated SOCS3^fl/fl or Socs3^fl/flcre^ΔLck mice were subjected to MLR. All graphs indicate mean±SEM. Data are representative of 2–4 independent experiments with 2–3 mice per group for murine studies or 5 human samples for human studies. Statistical analysis was performed using One or Two-Way ANOVA with Bonferroni's post-test where appropriate. *p<0.05, **p<0.01, ***p<0.001. See also supplemental figures S6–7.