Fig. 2

32A9 scFv-mPE24 and 42A1 scFv-mPE24 showed different antitumor activities in vitro and in vivo. A Schematic diagram of 32A9 (blue), 42A1 (red) antibody and GPC3 molecule (brown). B Flow cytometry to detect the antibody-binding activity and specificity to A431-GPC3 cells. Gray: Negative control, blue: 32A9, red: 42A1. C Flow cytometry to detect internalized Alexa 488-labeled 32A9 (blue) and 42A1 (red). D Schematic diagram of 32A9 scFv-mPE24 and 42A1 scFv-mPE24. PE: Pseudomonas exotoxin A. E SDS‒PAGE to show the purified scFv-mPE24. R: reducing. NR: nonreducing. F WST assay to detect the cytotoxicity of 32A9 scFv-mPE24 and 42A1 scFv-mPE24. The dashed line indicates the IC₅₀ value. Values represent the mean ± SD, n = 3 individual tests. Nude mice were subcutaneously injected with five million A431-GPC3 cells and then treated with 5 mg/kg (G) or 2.5 mg/kg (H) immunotoxin every day. Arrow indicated individual injections. Body weight of the mice was recorded, n = 5/group, Values represent mean ± SEM, with *P < 0.05, **P < 0.01 (paired Student’s t-test). Tumor growth after immunotoxin treatment was monitored by measuring tumor size. n = 5/group. Values represent the mean ± SEM, with *P < 0.05, **P < 0.01 (paired Student’s t-test)