Fig. 2. CASTAT5 CD4+ T cell-mediated tumor rejection is dependent on host CD8+ T cells and associated with antigen epitope spreading and DC activation.
(A) CASTAT5 CD4+ T cells mediate complete rejection of advanced tumors. Following the experimental time line depicted in Fig. 1A, mice with established A20HA tumors were randomly assigned into four groups to receive the specified treatments. Tumor growth curves of mice in each group are shown. The number of mice in each group is given. (B) Representative images of tumors in mice before treatment and at different time points after treatment. (C) Host CD8+ T cells contribute to CASTAT5 CD4+ T cell-mediated tumor rejection. The schema depicts the timeline of experimental procedures. Tumor growth curves indicate the impact of host CD8+ T cells on CASTAT5 CD4+ T cell-mediated tumor rejection. The numbers denote the number of tumor-free mice out of all treated mice. (D) Host CD8+ T cells are reactive to HA and other tumor-associated antigens. Following the timeline depicted in the schema, purified, violet dye-labeled host CD8+ T cells were incubated with equal number of irradiated A20HA, A20WT or MOPC315 cells. 6 days later, CD8+ T cells were evaluated for cell division (violet dye dilution) and activation (CD25 and CD44) by flow cytometry. Representative dot plots are shown. The numbers indicate the percentage of cells in the corresponding quadrant. The frequencies of divided CD8+ T cells under each culture condition are summarized in bar graphs and shown as mean ± s.d. of triplicate cultures. Data shown are representative of two independent experiments. (E) Frequencies of CD8α+CD103+CD11c+ dendritic cells in mice after treatment. Tumor-bearing mice were treated as described in Fig. 1A. 10 days after T cell transfer, mice were sacrificed to collect tumor draining lymph nodes (dLNs) and spleens for flow cytometry analysis. Representative dot plots are shown. The results are summarized in the bar graph shown as mean ±s.d. of three sample per group. Date are representative of two independent experiments. **p < 0.01, ***p < 0.001.