Fab antibody fragment
titer improvement
Challenge
- A partner was developing a Fab fragment to quickly neutralize a therapeutic substrate
- Their E. coli platform generated low Fab titer and meaningful supply was needed for clinical development
- A cost effective process required titers >2 g/L
Solution
- Hundreds of toolbox strains screened at 96-well scale to identify optimized expression of assembled and active Fab
- Fermentation at 2L scale achieved Fab titers > 4 g/L
SCREENING WORKFLOW
- 800 unique expression strains screened at 96-well scale
- Down-selected strains assessed at 2L scale for Fab titer under multiple induction conditions (pH, temp; induction OD, time, and inducer concentration)
- Fab enriched from selected fermentation pastes via affinity chromatography
- Enriched Fab quality assessed for intact mass
- >4g/L of active Fab produced
Key Results
- 2L fermentations produced assembled Fab over 96-hour induction time
- Active Fab titers from lysate >4 g/L (SDS-CGE and BLI)
2L Fermentation Lysate Samples
One strain, one induction condition shown; triplicate analytical samples (0 – 48 hours post induction; SDSCGE, non-reduced)