FIGURE 7.

Blockade of IL‐17A from tumor‐associated neutrophil‐polarized IL‐17A‐producing Th subsets inhibits tumor growth and GC progression in vivo. (A and B) GC cells were stimulated with the culture supernatants from autologous peripheral CD4⁺ T cells and tumor‐derived neutrophils plus control IgG or IL‐17A neutralizing antibody, or the culture supernatants from autologous peripheral CD4⁺ T cells and TTCS‐conditioned neutrophils plus control IgG or IL‐17A neutralizing antibody, or exposed to IL‐17A as described in Methods. The proliferation of GC cells was analyzed by using CCK‐8 Kits (A) and Ki‐67 staining (B) (n = 3). **P < 0.01 for groups connected by horizontal lines. (C) Mice were injected with human SGC‐7901 cells, as described in Section 2. The control animals received no further injections. The experimental treatments entailed injections with CD4⁺ T cells in combination with NTCS‐conditioned neutrophils (NCN) or with CD4⁺ T cells in combination with TTCS‐conditioned neutrophils (TCN), followed sequentially injecting with IL‐17A blocking antibody or control IgG. The illustrated data represent tumor volumes (5 mice in each group). The day of tumor cell injection was counted as day 0. **P < 0.01, for groups injected with CD4⁺ T cells in combination with TCN and anti‐IL‐17A antibody, compared with groups injected with CD4⁺ T cells in combination with TCN and control IgG. The tumors were excised and photographed 22 days after injecting the tumor cells. (D) The proliferating cell nuclear antigen (PCNA) and IL‐17A expressions (brown) in tumors were analyzed. Scale bars: 100 microns. The arrowheads indicated PCNA positive or IL‐17A positive cells. (E) Mice were injected with human SGC‐7901 cells, as described in Methods. The experimental treatments entailed injections with CD4⁺ T cells in combination with TTCS‐conditioned neutrophils (TCN) plus B7‐H2 blocking antibody or control IgG. The illustrated data represent tumor volumes (5 mice in each group). The day of tumor cell injection was counted as day 0. **P < 0.01, for groups injected with CD4⁺ T cells in combination with TCN plus B7‐H2 blocking antibody, compared with groups injected with CD4⁺ T cells in combination with TCN plus control IgG. The tumors were excised and photographed 22 days after injecting the tumor cells. (F) The proliferating cell nuclear antigen (PCNA) and IL‐17A expressions (brown) in tumors were analyzed. Scale bars: 100 microns. The arrowheads indicated PCNA positive or IL‐17A positive cells