The Combination of a Low-Dose Chemotherapeutic Agent, 5-Fluorouracil, and an Adenoviral Tumor Vaccine Has a Synergistic Benefit on Survival in a Tumor Model System
Figure 5
Effect of depleting MDSCs from variously vaccinated tumor-bearing mice on survival and tumor-specific T lymphocyte responses.
A. Tumor-bearing mice were treated with multiple i.p. doses of RB6-8C5 (as described in materials and methods section) and draining lymph node and spleen cells were isolated after 6 days of depletion (day 12 post-tumor challenge) and stained for the presence of gMDSCs (CD11b+Ly6C+lowLy6G+) and mMDSCs (CD11b+Ly6C+hiLy6G−). Data is presented as a percentage of total lymph node or spleen populations. Student T-test was used to determine statistical significance. B. Survival analysis: C57BL/6 mice were challenged with E.G7 and then, 7 days post tumor challenge, were treated as indicated. Survival curve represents pooled data from 2 independent experiments where a total of n = 8 mice/treatment group were used. Statistical analysis (Log-rank (Mantel-Cox) test) of survival data revealed that only the Ad5-OVA plus 5-FU treatment to be significantly different from all other treatments (*** P<0.001). C. Two weeks post-treatment the levels of OVA-specific CD8+ T cells, as a percentage of total CD8+CD3+ cells, was determined using a fluorescently-tagged OVA tetramer (see materials and methods for further details), in PBLs. Results displayed represent pooled data from 2 independent experiments and were performed in conjunction with the survival studies (see above (B.)). Statistical significance was determined using an ANOVA one way analysis of variance (with Tukey post-test) (*P<0.05). All error bars represent standard error of the mean.