Figure 1.

Biodistribution of Anti-ICAM/ASM NCs Containing Different ASM Loads

Wild-type (C57BL/6) mice were i.v. injected with anti-ICAM/¹²⁵I-ASM polystyrene NCs containing 0.06, 0.3, or 0.6 mg ASM/kg body weight (all at 1.8 × 10¹³ NCs/kg body weight). (A) The ¹²⁵I content of blood samples taken 1, 15, and 30 min after injection was used to calculate the percent of the injected dose (%ID) in the circulation. (B) Similarly, the ¹²⁵I content in the lungs, liver, and spleen isolated at sacrifice 30 min after injection, was used to determine the biodistribution (percent of the injected dose) in these organs. (C) The specificity index was calculated by normalizing tissue-over-blood accumulation for the targeted (anti-ICAM/ASM NCs) versus naked (ASM) enzyme, at matching ASM doses (see Materials and Methods). (D) The absolute amount of ASM delivered to these organs was calculated from their ¹²⁵I-ASM content and specific radioactivity (counts per minute/milligram) of the enzyme. Data are mean ± SEM (n = 3–6 mice). *Compares formulations to the lowest ASM load; ^#compares highest load formulation to the intermediate ASM load (p ≤ 0.1 by Student’s t test).