Egr2 deletion leads to resistance to SEB-induced anergy in vivo and enhanced anti-tumor immune response. (A) Deletion of Egr2 gene in T cells from CD4-Cre × Egr2^flox/flox was confirmed by immunoblot. (B) CD4-Cre × Egr2^flox/flox and control B6 mice were intraperitoneally injected with SEB (20 µg/mouse) or PBS. 7 d later, equal numbers of Vβ8⁺ cells were stimulated with SEB and T cell–depleted irradiated splenocytes. IL-2 production was assessed 48 h later. (C) Cre adenovirus-mediated Egr2 deletion was confirmed by intracellular staining/flow cytometry. (D) EV- or Cre-transduced cells were adoptively transferred into OT-1 TCR Tg × Rag2^−/− mice, which were intraperitoneally injected with SEB or PBS the next day. Rechallenge was conducted as described in B. (E–G) CD4-Cre × Egr2^flox/flox and control B6 mice were implanted with 2 × 10⁶ B16. SIY cells subcutaneously. Tumor size was measured on the indicated days (E). After 14 d, the mice were sacrificed and the percentage of SIY-specific CD8⁺ T cells was determined by SIY-K^b pentamer staining. OVA-K^b pentamer was used as a negative control (F). The SIY-specific functional T cell response was analyzed by IFN-γ ELISPOT from splenocytes. Data are represented as mean ± SEM, and are representative of two to three independent experiments. n = 5–7 mice per group per experiment. *, P < 0.05; **, P < 0.01; n.s., not statistically significant.