Figure 2.

α–CTLA-4 increases the number of tumor-specific CD4⁺ T eff and T reg cells in lymph nodes while preventing intratumoral T reg cell accumulation. Mice were challenged with 1.5 × 10⁵ B16-BL6 on day 0, adoptively transferred with 5 × 10⁴ CD4⁺CD45.1⁺ Trp1 T on day 3, and treated with GVAX or GVAX+α–CTLA-4 on day 3, 6, and 8. (A) Foxp3 expression by CD4⁺Vβ14⁺ cell isolated from Trp1 SJL RAG tan mice before transfer. (B and C) Absolute cell numbers and Foxp3 expression by CD4⁺CD45.1⁺ Trp1 T cells from the lymph node (B) and tumor (C). (D) Foxp3 expression by intratumoral CD4⁺CD45.1⁺ Trp1 T cells. Mice were treated as described above, but were also left untreated or treated with α–CTLA-4 monotherapy. n = 5 mice per group. *, P < 0.05; **, P < 0.01; ***, P < 0.001. Experiments were repeated two times.