title: Towards protein crystallization as a process step in downstream processing of therapeutic antibodies: screening and optimization at microbatch scale.
abstract: Crystallization conditions of an intact monoclonal IgG4 (immunoglobulin G, subclass 4) antibody were established in vapor diffusion mode by sparse matrix screening and subsequent optimization. The procedure was transferred to microbatch conditions and a phase diagram was built showing surprisingly low solubility of the antibody at equilibrium. With up-scaling to process scale in mind, purification efficiency of the crystallization step was investigated. Added model protein contaminants were excluded from the crystals to more than 95%. No measurable loss of Fc-binding activity was observed in the crystallized and redissolved antibody. Conditions could be adapted to crystallize the antibody directly from concentrated and diafiltrated cell culture supernatant, showing purification efficiency similar to that of Protein A chromatography. We conclude that crystallization has the potential to be included in downstream processing as a low-cost purification or formulation step.
authors.affiliation: Institute of Pharmaceutical Biotechnology, Biberach University of Applied Sciences, Biberach, Germany. zang@hochschule-bc.de
authors.forename: Yuguo
authors.initials: Y
authors.lastname: Zang
authors.forename: Bernd
authors.initials: B
authors.lastname: Kammerer
authors.forename: Maike
authors.initials: M
authors.lastname: Eisenkolb
authors.forename: Katrin
authors.initials: K
authors.lastname: Lohr
authors.forename: Hans
authors.initials: H
authors.lastname: Kiefer
mesh_terms: D000818:Animals; D000906:Antibodies / Q000737:chemistry* / Q000302:isolation & purification; D000911:Antibodies, Monoclonal / Q000737:chemistry / Q000302:isolation & purification; D016466:CHO Cells; D006224:Cricetinae; D003460:Crystallization / Q000379:methods*; D007074:Immunoglobulin G / Q000737:chemistry / Q000302:isolation & purification; D011485:Protein Binding; D011506:Proteins / Q000737:chemistry* / Q000302:isolation & purification; D013205:Staphylococcal Protein A / Q000737:chemistry / Q000378:metabolism
chemical_list: D000906:Antibodies; D000911:Antibodies, Monoclonal; D007074:Immunoglobulin G; D011506:Proteins; D013205:Staphylococcal Protein A