Effect of Ad-39-kD on the plasma clearance of¹²⁵I-Xa and ¹²⁵I-X. As described in the Materials and Methods, mice were injected with 10 pmol of plasma-derived ¹²⁵I-Xa (A) or recombinant¹²⁵I-Xa (B) or ¹²⁵I-X (C) with (○) or without (•) preinjection of 4 × 10¹¹ particles of Ad-39-kD 5 days previously. Blood samples were collected at the indicated times and trichloroacetic acid-insoluble radioactivity was determined.