Tumor-Shed Antigen Affects Antibody Tumor Targeting: Comparison of Two ⁸⁹Zr-Labeled Antibodies Directed against Shed or Nonshed Antigens

Figure 2

Effects of total injection dose of mAb on the BD of ⁸⁹Zr-mAb in nude mice ( = 4-5 per group) with A431/H9 tumor: (a) the BD data from ⁸⁹Zr-amatuximab (111 kBq) with different injection doses of amatuximab (2 µg, 10 µg, and 60 µg) are compared at 24 h p.i. in nude mice with tumor sizes , , and  mm³ for 2, 10, and 60 µg amatuximab. The results demonstrate that tumor uptake and blood retention significantly increased whereas liver uptake decreased as the antibody dose was increased; (b) the BD data from ⁸⁹Zr-B3 (74 kBq) with different injection doses of B3 (2 µg, 15 µg, and 60 µg) are compared at 24 h p.i. in nude mice with tumor sizes , , and  mm³ for 2, 15, and 60 µg. The results demonstrate that tumor uptake, blood retention, and liver uptake were not affected by the antibody dose. The data are mean ± SD. Analysis of statistical significance in each organ uptake data compared to the data from 2 µg injection: , , and ; column: mean; bar: SD.

(a)

(b)