Identification and characterization of host cell protein product-associated impurities in monoclonal antibody bioprocessing

Biotechnol Bioeng. 2014 May;111(5):904-12. doi: 10.1002/bit.25158. Epub 2013 Dec 11.


Downstream processing of monoclonal antibodies (mAbs) has evolved to allow the specific process for a new product to be developed largely by empirical specialization of a platform process that enables removal of impurities of different kinds. A more complete characterization of impurities and the product itself would provide insights into the rational design of efficient downstream processes. This work identifies and characterizes host cell protein (HCP) product-associated impurities, that is, HCP species carried through the downstream processes via direct interactions with the mAb. Interactions between HCPs and mAbs are characterized using cross-interaction chromatography under solution conditions typical of those used in downstream processing. The interacting species are then identified by two-dimensional gel electrophoresis and mass spectrometry. This methodology has been applied to identify product-associated impurities in one particular purification step, namely protein A affinity chromatography, for four therapeutic mAbs as well as the Fab and Fc domains of one of these mAbs. The results show both the differences in HCP-mAb interactions among different mAbs, and the relative importance of product association compared to co-elution in protein A affinity chromatography.

Keywords: host cell protein impurities; mAb process development; protein A affinity chromatography; protein-protein interactions.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Antibodies, Monoclonal / isolation & purification*
  • CHO Cells
  • Chromatography, Affinity / methods*
  • Cricetinae
  • Cricetulus
  • Electrophoresis, Gel, Two-Dimensional
  • Proteins / analysis*
  • Proteins / chemistry*
  • Recombinant Proteins / isolation & purification*


  • Antibodies, Monoclonal
  • Proteins
  • Recombinant Proteins