A mandatory role for the IL-17A–IL-17RA pathway in the efficacy of chemotherapy. (A) Mice bearing established MCA205 sarcomas were treated with local PBS (filled symbols) or DX (open symbols) 7 d after tumor inoculation and with systemic neutralizing antibodies against mouse IFN-γ (left), IL-17A (right), or control Ig (CIg) i.p. every 2 d (3 injections, 200 µg/mouse) starting on the day of DX. (B–E) WT (circles or squares) or IL-17A^−/− (triangles) mice bearing established MCA205 sarcomas (B), MCA2 (C), EG7 (D), or CT26 (E) tumors were treated with PBS (B-E, solid symbols), DX (B and C, open symbols), or OX (D and E, open symbols) together with systemic administration of neutralizing antibodies against IL-17RA (squares) or CIg. Tumor sizes are plotted as mean ± SEM for 5–15 mice/group, and each experiment was repeated at least 2 times, yielding similar results. *, P < 0.05; **, P < 0.01.