Tumor Invasion of Salmonella enterica Serovar Typhimurium Is Accompanied by Strong Hemorrhage Promoted by TNF-α
Figure 1
Time course of bacterial accumulation in different organs and bacterial colonization of solid CT26 tumors.
Tumor bearing mice were infected i.v. with S. Typhimurium SL7207. (a) 2 h, 6 h, 12 h, 24 h and 48 h p.i. tumor and spleen were homogenized. Tumor, spleen and blood were plated and the CFUs per total organ were determined. (b) Non-invasive in vivo imaging of bacterial bioluminescence. Tumor-bearing mice were infected with S. Typhimurium expressing the luxCDABE operon of Photorhabdus luminescens under the control of the β-Lactamase promoter. Arrows show sites of high bacterial accumulation. Images were taken at the indicated time points. (c) High magnification images of tumor cryosections at the indicated time points p.i. with S. Typhimurium SL7207. In all pictures, bacteria are stained in green, blood vessel endothelial cells are stained in blue and neutrophilic granulocytes are stained in red. White arrows point at individual Salmonella. White bars correspond to 10 µm in all pictures. (d) Overviews of CT26 tumor cryosections at the indicated time points p.i. with S. Typhimurium SL7207. Stainings are described in (c). White bars correspond to 100 µm in all pictures. Experiments were repeated at least three times with identical results.