Cation exchange versus multimodal cation exchange resins for antibody capture from CHO supernatants: identification of contaminating host cell proteins by mass spectrometry.

We compared classical and multimodal cation exchange resins for the capture of recombinant antibodies from Chinese hamster ovary (CHO) cell culture supernatant. Both Capto S and Capto MMC resins present anionic groups while the multimodal Capto MMC also features a hydrophobic moiety. First we screened optimal binding and elution conditions in microplates with a pure antibody. We validated the results on the lab-scale with columns with a pure antibody and a CHO cell culture supernatant. Both resins achieved good yield and purity for the capture step of an antibody. However, the multimodal resin appeared more efficient and selective. Then we identified proteins in the antibody fraction by mass spectrometry in order to highlight the behavior of host cell proteins (HCPs).