Figure 5.

Effects of G-MDSCs and mature PMN on tumor growth. (A and B) Isolated G-MDSCs or PMN from bone marrow bands III and IV of melanoma-bearing mice were intratumorally injected (i.t.) into recipient mice that bore melanoma tumors (tumor size ~ 100 mm³) for three consecutive days (days 12, 13, and 14). Tumor growth was recorded (A) and tumor infiltrated T cells were analyzed on day 15 (B). (C) B16 cells were co-cultured with PMN in the absence or presence of PMA for 18 h. (D and E) Bone marrow PMN (band IV) isolated from healthy or tumor-bearing mice were intratumorally injected into recipient melanoma tumors. To activate PMN, a set of mice were given the second injections of a mixture of PMA, zymosan and fMLP. These procedures were performed three times (d 12, 13, and 14). Tumor growth (D) and the overall survival rates (E) were analyzed. Demonstrated data (A–D) represent at least three independent experiments with five or six mice per experiment. Data in B and C are presented as mean ± SEM. The significant differences between the tested groups were calculated by one-way ANOVA followed by Dunnett’s Multiple Comparison test. *p ≤ 0.05; **p ≤ 0.01; ***p ≤ 0.001.