Figure 5.

SUREK reduces the Cd4/Cd8 ratio and leads to activation of Cd4+ and Cd8+ tumor-infiltrating T cells in an immunocompetent murine model for neuroblastoma minimal residual disease. (A) Schematic representation of experimental design and time point of analysis. A/J mice were intravenously (+) injected with 1×10⁶ viable NXS2 cells into a lateral tail vein. Mice received a single intraperitoneal (i.p.) injection of 10 µg SUREK (n=7) or PBS only (n=5) 17 days (d) later. Five days after antibody treatment, mice were sacrificed to tumor infiltrating T cells and splenic T cells. (B) Representative dot plots indicating gating strategy to select tumor infiltrating T cells and determine Cd4/Cd8 ratio in spleen and tumor by flow cytometry. Quantification of (C) Cd69 and (D) Cd25 expression by flow cytometry on Cd4+ and Cd8+ T cells isolated from spleen and tumor. Results are pooled from two independent experiments. Mann-Whitney test; **p<0.01; *p<0.05; n.s., not significant. PBS, phosphate-buffered saline.