Figure 2. Effect of NADPH oxidase in local and systemic accumulation of MDSCs in tumor-bearing mice.

A) Representative quantification of MDSCs. Splenocytes from WT and p47^phox−/− mice at day 42 and 90 after MOSEC administration were analyzed for MDSC accumulation. Gating on myeloid (CD11b⁺) cells, the proportion of monocytic MDSCs (R1; Ly6C⁺Ly6G⁻) and granulocytic MDSCs (R2; Ly6G⁺Ly6C^Low) significantly increased at day 90 versus day 42. All gates were set based on isotypes. This approach was used to quantify MDSCs in PECs, lymph nodes, and spleens. B) Proportion of MDSCs in myeloid PECs on day 42 and 90. The proportion with granulocytic and monocytic MDSC markers was greater in advanced (day 90) versus early (day 42) stage tumor burden in both genotypes. C) In draining lymph nodes, there was a trend toward increased monocytic MDSC accumulation in p47^phox−/− versus WT mice at day 42 but not at day 90. There was no effect of NADPH oxidase on granulocytic MDSC accumulation at either time point. D) In spleens, there was an increased accumulation of MDSCs, particularly granulocytic MDSCs, in mice with advanced versus early disease, but no effect of mouse genotype. Data (± SEM) are from at least 3 mice per genotype per time point, and are representative of 3 separate experiments. Comparison between genotypes: p = NS.