3.4 89Zr-IP150 cell uptake and affinity
test
The in vitro binding assay of 89Zr-P150 to the MUC18
(+) cell line A375 demonstrated a Kd of 2.431 nM and an
R2 of 0.9718 (Figure 2H).
The time-dependent uptake of 89Zr-IP150, which could
be blocked by the unconjugated IP150 mAb, was observed in MUC18 (+)
A375, SK-Mel-28 and HMVII cells, but no uptake of89Zr-IP150 was observed in MUC18 (-) A549 cells
(Figure 2I). At 240 min, the cell uptake was 10.96±1.11 vs. 1.13±0.22
IA%/2×105 cells in A375, 10.76±0.77 vs. 0.75±0.11 in
the IA%/2×105 SK-Mel-28 cells, 9.49±0.66 vs.
1.05±0.15 in the IA%/2×105 HMVII cells, respectively
(p <0.001). Moreover, at 240 min (Figure 2J), the uptake
of 89Zr-IP150 by MUC18 (-) A549 cells (0.43±0.05
IA/2×105 cells) was significantly lower than that by
the three MUC18 (+) cell lines (p <0.001).