title: Characterization and identification of alanine to serine sequence variants in an IgG4 monoclonal antibody produced in mammalian cell lines.
abstract: Low levels of alanine to serine sequence variants were identified in an IgG4 monoclonal antibody by ultra/high performance liquid chromatography and tandem mass spectrometry. The levels of the identified sequence variants A183S and A152S, both in the light chain, have been determined to be 7.8-9.9% and 0.5-0.6%, by extracted ion currents of the tryptic peptides L16 and L14, respectively. The A183S variant was confirmed through tryptic map spiking experiments using synthetic peptide, SDYEK, which incorporated Ser at the position of native Ala in the tryptic peptide L16. Both mutations were also observed by endoproteinase Asp-N peptide mapping. The variant level of A183S was also quantified by LC-UV with detection at 280nm and fluorescence detection of tyrosine residues on the tryptic peptides. The results from LC-MS, UV, and fluorescence detection are in close agreement with each other. The levels of the sequence variants are comparable among the antibody samples manufactured at different scales as well as locations, indicating that the variants' levels are not affected by manufacture scale or locations. DNA sequencing of the master cell bank revealed the presence of mixed bases at position 183 encoding both wild and mutated populations, whereas bases encoding the minor sequence variant at position 152 were not detected. The root cause for A152S mutation is not yet clearly understood at this moment.
authors.affiliation: Biologics Manufacturing and Process Development, Global Manufacturing and Supply, Bristol-Myers Squibb, Princeton, NJ 08543, United States. jinmei.fu@bms.com
authors.forename: Jinmei
authors.initials: J
authors.lastname: Fu
authors.forename: Jacob
authors.initials: J
authors.lastname: Bongers
authors.forename: Li
authors.initials: L
authors.lastname: Tao
authors.forename: Dan
authors.initials: D
authors.lastname: Huang
authors.forename: Richard
authors.initials: R
authors.lastname: Ludwig
authors.forename: Yunping
authors.initials: Y
authors.lastname: Huang
authors.forename: Yueming
authors.initials: Y
authors.lastname: Qian
authors.forename: Jonathan
authors.initials: J
authors.lastname: Basch
authors.forename: Joel
authors.initials: J
authors.lastname: Goldstein
authors.forename: Ramji
authors.initials: R
authors.lastname: Krishnan
authors.forename: Li
authors.initials: L
authors.lastname: You
authors.forename: Zheng Jian
authors.initials: ZJ
authors.lastname: Li
authors.forename: Reb J
authors.initials: RJ
authors.lastname: Russell
mesh_terms: D000409:Alanine / Q000032:analysis / Q000737:chemistry* / Q000235:genetics; D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000096:biosynthesis / Q000737:chemistry* / Q000235:genetics; D016466:CHO Cells; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D006224:Cricetinae; D003412:Cricetulus; D018076:DNA, Complementary / Q000235:genetics; D006801:Humans; D007074:Immunoglobulin G / Q000737:chemistry* / Q000235:genetics; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000032:analysis / Q000737:chemistry; D010449:Peptide Mapping / Q000379:methods*; D012694:Serine / Q000032:analysis / Q000737:chemistry* / Q000235:genetics; D053719:Tandem Mass Spectrometry / Q000379:methods; D014357:Trypsin / Q000737:chemistry
chemical_list: D000911:Antibodies, Monoclonal; D018076:DNA, Complementary; D007074:Immunoglobulin G; D010446:Peptide Fragments; D012694:Serine; D014357:Trypsin; D000409:Alanine