Creation of a broadly reactive E. coli HCP detection ELISA suitable for K Strain and B Strain Platforms

ELISA is a workhorse method of measuring host cell protein (HCP) impurities throughout downstream bioprocessing, monitoring HCP removal and thereby helping to ensure consistency in manufacturing of biopharmaceutical products. ELISA also acts in conjunction with, and orthogonally to, other analytical methods such as 2D Western blot and mass spectrometry.

Escherichia coli (E. coli), is among the most commonly used host organisms for scientific research and biotechnological applications, with approximately 30% of biopharmaceuticals being produced in E. coli. With respect to biotechnology, there are two major E. coli strain types which have application specific advantages. E. coli B strains have been optimized for fast growth and highly controllable protein expression and are most often used for recombinant protein expression. E. coli K-12 strains have greater genetic stability but lack some features for protein expression and are thus most commonly used for the generation of plasmids to support gene therapy programs. The use of bacterial cells, such as E. coli, in the generation of therapeutic biologics and genetic material requires the monitoring of impurities, which can include host cell proteins, host cell DNA, as well as growth media components.

Here we present the development of a new E. coli HCP antibody reagent and the corresponding validated ELISA for detection of E. coli HCP impurities in downstream bioprocessing. This E. coli HCP ELISA has been qualified for monitoring HCPs at all steps in the bioprocessing workflow for both recombinant proteins (produced by E. coli B strains) and for plasmid production that support gene therapies (produced by E. coli K-12 strains).