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

Figure 6

Autoradiography analysis of ⁸⁹Zr-mAbs depicted as normalized intensity versus normalized length profiles: ⁸⁹Zr-amatuximab (2.96 MBq) was coinjected with (a) 10 µg and (b) 60 µg amatuximab. ⁸⁹Zr-B3 (2.22 MBq) was coinjected with (c) 15 µg and (d) 60 µg B3. The results demonstrate that the normalized radioactivity of ⁸⁹Zr-amatuximab at the tumor core and the periphery was similar with the low dose of amatuximab but the relative ⁸⁹Zr intensity at the tumor periphery was higher as the injection dose was increased to 60 µg. In contrast, the radioactivity profile of ⁸⁹Zr-B3 was not affected by the B3 dose between 15 and 60 µg B3 and the radioactivity preferentially accumulated in the tumor periphery.

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