Monoclonal antibodies (mAbs) consist of variable domain, interacting with the antigen, and a constant domain, necessary for an immune response via Fcγ receptors, as well as for mAb half-life by interaction with the neonatal Fc receptor (FcRn). Therefore, it is important to study the affinity of mAbs and their proteoforms with these receptors. Common approaches, such as SPR, provide an overall affinity response for all different mAb proteoforms rather than in a proteoform specific manner. In this presentation, we want to show an innovative approach based on sheathless CE-MS to study relative affinities of different mAb proteoforms with the FcRn and FcyRIIa receptor. To determine the separation was performed using ammonium acetate pH 6 or 6.8 for FcRn or FcyRIIa, respectively. We will show that we are able to determine the affinity of mAb proteoforms as a consequence of their different mobility shifts, using different amounts of FcR in the background electrolyte. Hyphenation to MS allowed us to detect the mAb alone as well as in complex with one or two FcRs.
- Zaal 2
- SAC CE