Clodrolip depletes macrophages in F9-teratocarcinoma bearing mice. (A) Size distribution of control and clodrolip tumors at day 10, 17 and 23 after treatment initiation. (B) Upper panel: HE staining of a control tumor section (left) and a clodrolip treated tumor section (right), magnification 2.5×. Note the large necrotic center in the clodrolip treated tumor (right panel). Panels: Immunohistochemical analysis of CD68+ (red) and F4/80+ (green) density in control (left) and clodrolip treated (right) tumors, magnification 10×. Overlay of double-positive macrophages is shown in orange (lower panel); scale bar = 0.2 mm. Macrophage-rich regions are delineated by white lines. Macrophage magnification of 100 × is displayed in each picture at the upper right corner; scale bar = 0.02 mm. Nuclei were stained with DAPI (blue). (C) Quantitative analysis of F4/80+ (left) and CD68+ (right) cell density in control and clodrolip treated tumors; n = 3/group, bars: means ± SEM; *P < 0.05, unpaired t-test. (D) Relative gene expression (mRNA levels) of Cd68 and Csfr-1 in clodrolip treated vs. control tumors; n = 6, bars: means ± SEM.