Figure 1. Transfer of tumor-specific Th9 cells prevents the relapse of variant tumors.

(A) TRP-1-specific Th1, Th17, Th9 cells (CD45.2⁺, regular dose, 2.5×10⁶), high dose Th1 (2×10⁷), or high dose Th17 cells (7.5×10⁶) were transferred i.v. into CD45.1⁺ B6 mice bearing 10-day large established B16 tumors (1×10⁶ B16 cells challenged s.c. 10 days before T cell transfer). Adjuvant cyclophosphamide (CTX, i.p.) and DC vaccination (2.5×10⁵, i.v.) were administered to some mice as indicated. (B) Tumor responses to TRP-1 cell transfer are shown (n=5/group). The description of tumor-free survival is summarized from several independent studies. (C-D) Tumors were harvested from No-T-cell-treated mice, Th1 or Th17-cell-treated mice. Images of representative tumors are shown in (C). Tumor tissue lysates were analyzed for TRP-1 expression by western-blot (D). (E) Intracellular staining of TRP-1 in B16^10%TRP-1-KO and B16^TRP-1-KO tumor cells. (F) B16^10%TRP-1-KO tumor (contain 10% B16^TRP-1-KO ALVs)-bearing mice were treated similarly to Fig. 1A. Surviving mice in the Th9-cell-treated group were rechallenged with 2×10⁶ ALVs (B16^TRP-1-KO) on day 60. Tumor responses are shown (n=5/group). Representative results from one of two repeated experiments are shown (total # of mice/group ≥ 20 in B; ≥ 10 in F).