Biodistribution of fusion proteins L19–IL-2 and D1.3–IL-2.

(A) Tumor-blood ratio (T/B) of the %ID/g at 3, 6, and 24 hours after intravenous injection of radioiodinated L19–IL-2 and D1.3–IL-2 in F9 teratocarcinoma-bearing mice. Mice with subcutaneously implanted tumors were intravenously injected with 10 μg (4 μC; 0.148 MBq) of protein in 100 μL saline solution. Three animals at each time point were killed and organs were weighed and the radioactivity counted. Vertical bars indicate SE. (B) Microautoradiography of F9 teratocarcinoma 24 hours after injection of radioiodinated L19–IL-2. Radiolabeled L19–IL-2 accumulates around tumoral vascular structures, but not around vessels of normal tissues (data not shown).