Figure 2.

Fab fragment fusions of M60-A02 (anti-EGFR) and C06 (anti-IGF1R) were produced with HSA fused to the C-term of M60-A02 heavy chain (HC1-HSA) and GFP fused to the N-term of C06 light chain (GFP-LC2). The EFab is substituted for the CH1 domain of M60-A02 in the EFab-containing expressions. The schematic shows possible pairing options. Correct pairing of constructs produces bands at 114 and 74 kDa. Incorrect pairing results in bands at 47 and 141 kDa. The SDS-PAGE non-reducing gel shows that approximately equal amounts of correctly paired and incorrectly paired Fabs result when both Fabs have the WT CH1. EFab eliminates the incorrect pairing.