Figure 5.

Axitinib reduces the suppressive capacity of splenic CD11b⁺Ly6C^highLy6G^- cells. CD11b⁺Ly6C^highLy6G^- (moMDSCs) and CD11b⁺Ly6C^intLy6G⁺ (grMDSC) cells were sorted from the spleens of subcutaneous MO4-bearing mice on the 7th day of treatment with axitinib at 25 mg/kg bid or vehicle by oral gavage and were used in a suppression assay. Controls included T cells cultured in the absence of MDSCs with and without T-cell stimulation. CD11b⁺Ly6C^highLy6G^- cells sorted out of axitinib-treated mice had a reduced suppressive capacity. This effect was observed in a 1:1 (CD11b⁺Ly6C^highLy6G^- cell: T cell) ratio (A.) and was more distinct on CD8⁺ T cells (A. right panel) (A.) Overview of the percentage suppression of CD4⁺ T-cell proliferation (left panel) and CD8⁺ T-cell proliferation (right panel) cultured in the presence of different ratios of Ly6C^highLy6G^- MDSC (moMDSC) and (B.) in the presence of different ratios of Ly6C^intLy6G⁺ MDSC (grMDSC). (C.) IFNγ, TNFα, and IL-2 production by splenocytes was determined after 3 d of co-culture with different ratios of Ly6C^highLy6G^– MDSC (moMDSC) and (D.) in the presence of different ratios of Ly6C^intLy6G⁺ MDSC (grMDSC). Three independent experiments were performed (4 mice per group, spleens were pooled per group before cell sorting) and results are presented as mean ± SEM.