title: Improved detection of host cell proteins (HCPs) in a mammalian cell-derived antibody drug using liquid chromatography/mass spectrometry in conjunction with an HCP-enrichment strategy.
abstract: BACKGROUND
  Host cell proteins (HCPs), which are process-related impurities typically present at low levels in recombinant biopharmaceutical products, are often measured using an immunological technique, such as an enzyme-linked immunosorbent assay (ELISA). In contrast to ELISA which only provides the total amount of HCP, liquid chromatography/mass spectrometry (LC/MS) can provide both qualitative and quantitative information about the major HCP species. In this study, an HCP-enrichment step was optimized and combined with LC/MS to identify and determine the relative abundance of HCPs present in a monoclonal antibody (mAb) drug product.
  
  
  METHODS
  An NS0 (mouse myeloma) cell-derived mAb drug product, whose total HCP level was less than 100 ng/mg of protein, was subjected to analysis by LC/MS. One-dimensional and two-dimensional chromatography options, together with the off-line HCP enrichment strategy based on Protein A chromatography, were evaluated for optimal HCP detection.
  
  
  RESULTS
  With this approach, nineteen HCPs were detected from a therapeutic mAb, an improvement over the detection of only one HCP without depletion.
  
  
  CONCLUSIONS
  Compared with other published HCP studies with LC/MS, the HCP-enrichment step in our method enables a more practical and relevant application to approved protein therapeutics, which are mostly mammalian cell-derived products with HCPs present at very low levels.
authors.affiliation: MedImmune, One MedImmune Way, Gaithersburg, MD, 20878, USA.
authors.forename: Jenny Heidbrink
authors.initials: JH
authors.lastname: Thompson
authors.forename: Wai Keen
authors.initials: WK
authors.lastname: Chung
authors.forename: Min
authors.initials: M
authors.lastname: Zhu
authors.forename: Liu
authors.initials: L
authors.lastname: Tie
authors.forename: Yali
authors.initials: Y
authors.lastname: Lu
authors.forename: Nabila
authors.initials: N
authors.lastname: Aboulaich
authors.forename: Robert
authors.initials: R
authors.lastname: Strouse
authors.forename: Wenjun David
authors.initials: WD
authors.lastname: Mo
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry* / Q000378:metabolism; D045744:Cell Line, Tumor; D002853:Chromatography, Liquid / Q000379:methods*; D013058:Mass Spectrometry / Q000379:methods*; D051379:Mice; D010446:Peptide Fragments / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D011506:Proteins / Q000032:analysis* / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry* / Q000378:metabolism; D014357:Trypsin
chemical_list: D000911:Antibodies, Monoclonal; D010446:Peptide Fragments; D011506:Proteins; D011994:Recombinant Proteins; D014357:Trypsin