Fig. 5.

In vivo imaging of 4T1 tumors under anti-PD-L1 therapy. (a) Measured tumor volumes over a period of 9 days. In the early course of treatment, no significant differences between the treatment groups receiving anti-PD-L1 (grey) and the control group (IgG-isotype control, black) were measurable. (b) S100A9-specific in vivo imaging revealed a significant decrease of fluorescence intensities under anti-PD-L1 treatment compared to the first imaging before therapy start, whereas no significant changes were detected in the control group.