Efficient removal of antibody aggregates using TOYOPEARL MX-Trp-650M mixed-mode resin under salt or pH gradient elution

Background: TOYOPEARL MX-Trp-650M is a mixed-mode resin (Tosoh Bioscience, Japan), which mediates both cation exchange and hydrophobic interactions. While mixed-mode resins are generally effective at removing antibody aggregates, reports specifically evaluating the application of MX-Trp-650M for this purpose remain limited. A previous study suggested that effective separation of monomeric and aggregated antibodies using MX-Trp-650M was achieved only under dual-gradient elution with pH and salt. Objective: This study aimed to further evaluate MX-Trp-650M’s aggregate separation potential under various elution conditions. Methods: In an antibody purification case where aggregates were the predominant byproducts, both Capto MMC ImpRes and MX-Trp-650M were evaluated as the first polishing step following Protein A capture. Aggregate separation was monitored and assessed using native gel electrophoresis and size-exclusion chromatography-high-performance liquid chromatography. Results: MX-Trp-650M marginally outperformed Capto MMC ImpRes and achieved excellent aggregate clearance under either salt or pH mono-gradient elution. Conclusion: Combining the results from prior studies, the current data confirm the strong aggregate separation capability of MX-Trp-650M. The results also suggest that the optimal elution conditions for efficacious separation may vary across different antibody purification scenarios.