TABLE 1.
Overview of Currently Available Preclinical Checkpoint Imaging Studies (for PD-L1)
| Targeting molecule | Radioisotope | Chelator | Animal model | Tumor model | Accumulation time | Study |
| PD-L1 | ||||||
| Murine mAb PD-L1.3.1 | 111In | DTPA | BALB/c nude mice | MDA-MB-231, SK-Br-3, SUM149, MCF-7, BT474 | 0, 1, 3, 7 d | (49) |
| Atezolizumab | 111In | DTPA | NSG mice | CHO-PDL1, CHO, H2444, H1155, MDA-MB-231, SUM149 | 24, 48, 72, 96, 120 h | (67) |
| Murine anti-PD-L1 antibody | 111In | DTPA | Neu-N transgenic mice | NT2.5 | 72 h | (53) |
| Antimouse PD-L1 antibody | 111In | DTPA | C57BL/6 mice | B16F10 | 24, 72 h | (54) |
| Antimurine anti-PD-L1 antibody α-PD-L1 (10F.9G2) | 64Cu | NOTA | C57BL/6N mice | B16F10 | 24 h | (55) |
| Anti-PD-L1 antibody C4 | 89Zr | DFO | nu/nu mice, C57 BL/6J mice | H1975, PC3, A549 | 8, 24, 48, 72, and 120 h | (51) |
| Atezolizumab | 64Cu | DOTAGA | NSG mice | CHO-hPD-L1, MDA-MB-231, CHO, SUM149 | 24, 48 h | (57) |
| Avelumab | 89Zr | DFO | Athymic nude mice | MDA-MB-231 | 1, 2, 3, 6 d | (56) |
| Antimurine anti-PD-L1 antibody 10F.9G2 | 89Zr | DFO | C57BL/6 mice | MEER, B16F10 | 48 h + 96 h | (59) |
| AntihPD-L1, clone PD-L1.3.1, antimPD-L1, clone 10F.9G2 | 111In | DTPA | BALB/c, C57BL/6, and NSG mice | Renca, 4T1, CT26, B16F1, LLC1 | 1, 3, 7 d | (52) |
| Atezolizumab | 89Zr | Df | Athymic nude mice | H460, A549 | 1, 6, 12, 24, 48, 72, 96 h | (60) |
| ZPD L1_1 Affibody | 18F-AlF | NOTA | SCID beige mice | LOX, SUDHL6 | 30–90 min | (65) |
| KN035 domain antibody containing Fc tail fused to 2 single domains (antihuman PD-L1) | 89Zr | DFO | BALB/c nude mice, nonhuman primates | LN229 | 1, 6, 24, 48, 72, 120 h | (61) |
| PD-L1 specific Fab fragment | 64Cu | NOTA | Athymic nude mice | — | 5, 15, 45 min | (62) |
| Anti-PD-L1 adnectin BMS-986192 | 18F | Athymic nude mice | HT-29, L2987 | 90–120 min | (66) | |
| Peptide WL12 | 64Cu | DOTAGA | NSG mice | CHO, hPD-L1 | 10, 30, 60, 120 min | (50) |
| Peptide WL12 | 68Ga | DOTAGA | NSG mice | hPD-L1, CHO, MDA-MB-231, SUM149 | 15, 60, 120 min | (68) |
| Peptide WL12 | 18F | NSG mice | hPD-L1, CHO, H226, H1155, MDA-MB-231, SUM149 | 10, 60, 120 min | (69) | |
| Single-domain antibodies C3, C7, E2 and E4 | 99mTc | C57BL/6 mice | HEK293T | 1 h | (63) | |
| Single-domain antibody Nb109 | 68Ga | NOTA | BALB/c nude mice | A375-hPD-L1, MCF-7 | 1, 2, 4 h | (64) |
DFO = deferoxamine.