Process-related impurities from host cell proteins (HCP) potentially contaminating large molecule biopharmaceutical products must be identified and monitored to guarantee the safety of the material and health of the drug recipient. HCPs may be residual contaminants left behind during the purification process from the expression hosts, such as E.Coli, insect, or mammalian cells and may potentially result in adverse events in patients. To investigate the presence of residual contamination during the bioprocessing purification stream and in the final biopharmaceutical product, the development of customized polyclonal antibody reagents with maximum coverage against native HCP extracts is required.
In the development of an HCP antibody, the immunogenicity and abundance of individual HCPs can vary widely presenting a unique challenge. Highly immunogenic proteins can disguise the effects of other, similar size proteins. Choosing the proper immunization strategy in combination with the validation of the HCP antibody at every step of development are key to ensure good coverage. The implementation of two-dimensional (2D) SDS-PAGE assessment, by which complex protein mixtures are separated according to isoelectric point and molecular weight followed by western blotting, can deliver additional insight into the capability of an anti-HCP polyclonal antibody with respect to immunocoverage of protein components of the host cell lysate. We present generic anti-HCP polyclonal antibodies (generated for bacterial and mammalian proteins) as an alternative to customized reagents that are functional for 2D WB and ELISA.
These HCP antibodies display sensitivity and specificity against a broad range of HCPs, measured by a robust 2D electrophoresis assay, to provide efficient immunocoverage against potential contaminants of biopharmaceutical products.