Demonstration of the ability of AdNK4 to inhibit tumor vascularization.

For immunohistochemical evaluations for CD31, BALB/c mice were injected subcutaneously in the right flank with 2 × 10⁵ Colon-26 cells (day 0). On day 8, tumor-bearing mice were treated by intratumoral injection of 10⁹ pfu of AdNK4 (A), AdNull (B), or PBS alone (no transduction, C). On day 11, tumors were dissected, and frozen tumor sections were stained using 12.5 μg/mL rat anti–mouse CD31 antibody, or isotype-matched control rat IgG followed by visualization with FITC-conjugated anti–rat IgG antibody. Nuclei were stained with DAPI (original magnification × 400). The number of CD31⁺ vessels per 10 random high-power fields is indicated in the lower right corner of each left panel.