Optimization of Enzymatic Antibody Fragmentation for Yield, Efficiency, and Binding Affinity.

Enzymatic antibody fragmentation has been well studied for various hosts and isotypes, but fragmentation patterns also vary unpredictably by clone, and optimizing Fab or F(ab')2 production by trial and error consumes large quantities of antibodies. Here, we report a systematic strategy for optimizing functional F(ab')2 production via pepsin digestion from small quantities of IgG. We tested three key parameters that affect fragmentation, pH, enzyme concentration (% pepsin w/w), and reaction time, and found that pH had the greatest impact on fragmentation yield and efficiency. We then developed a systematic approach to obtaining acceptable yields, digestion efficiency, and binding affinity. Three case studies are described to illustrate the approach. We anticipate that this work will provide a quick and cost-effective method for researchers to produce antibody fragments from whole IgG, avoiding haphazard trial and error.