Figure 5

The effect of CXCL12 on cell-mediated cytotoxicity and the accumulation of dendritic cells and MDSC. A) Cell-mediated cytotoxicity against 4T1.2 tumors. BALB/c mice were injected i.m.f.p. with 1 × 10⁵ cells. After approximately 5 weeks, effector cells were prepared for use in a cytotoxicity assay as described in Materials and Methods. *, P < 0.05, significantly different from naïve effectors and effectors from 4T12Ala tumor-bearing mice (Kruskal-Wallis). B-F) CD11c⁺ cell infiltration of tumor-draining lymph nodes. Cryostat sections from inguinal (B, D) and axillary (C, E) draining lymph nodes 6 days post 4T12Ala (B, C) or 4TX12 (D, E) cell injection were stained with anti-CD11c antibody. Magnification: 100×. F) CD11c⁺ cells were enumerated in ten randomly selected high power fields per lymph node. Bars represent the mean number (± SEM) of CD11c⁺ cells per field. n = 3 mice (i.e. 6 lymph nodes) per group from two independent experiments. ***, p < 0.0001 (t test). G-H) Accumulation of MDSC in spleens of tumor-bearing mice. BALB/c mice were injected i.m.f.p. with 1 × 10⁵ cells. Spleens were resected 28 days later and the percentage (G) and the absolute numbers (H) of Gr1⁺CD11b⁺ splenocytes in tumor-bearing and control (naïve) mice was determined by flow cytometry. Bars represent the mean ± SEM of duplicate determinations from 5 mice. ***, P < 0.0001 (t test).