Protein L resins bind to the antibody kappa light chain and can be used for purifying, for example, domain antibodies (dAbs) and antigen-binding fragments (Fabs), as well as to remove product-related impurities from bsAbs at capture. Unlike protein A resins, protein L resins bind to the free antibody light chain, which is then co-eluted with the antibody. This can be seen as a disadvantage as the light chain is often overexpressed during cell culture.
In this study, a buffer screening is performed to find alternative elution buffers for MabSelect™ VL resin. The focus was to increase elution pH and resolution between bsAb and its product-related impurities. The separation of a mAb and its overexpressed light chain will also be shown to demonstrate the selectivity.