Sensitive methods for evaluation of antibodies for host cell protein analysis and screening of impurities in a vaccine process

Host cell proteins (HCP) should be carefully monitored in vaccine production. To achieve a reliable HCP estimation, a mixture of polyclonal antibodies (pAbs) with broad affinity would be of preference. Sensitive evaluations of the pAbs are therefore of value. Column purification of specific HCPs with affinity to the anti-HCP pAbs was compared with Western blotting of the anti-HCP pAbs binding to filter bound total lysate. The anti-HCP pAbs were used in an HCP quantification analysis using surface plasmon resonance (SPR). Host cell derived impurities from an influenza vaccine process were analyzed using 2-D DIGE analysis. The Western blotting showed a similar HCP binding pattern of anti-HCP pAbs from immunizations using two adjuvants: CFA/IFA and AbISCO®. From the column purification of HCPs, total proteins detectable were similar for all anti-HCP pAbs; however the immune response pattern differed significantly for the anti-HCP pAbs from the AbISCO® immunization. In the SPR HCP quantification assay the standard curve ranged from 0.3 to 40 μg/ml. The advantage of SPR compared with ELISA was the decreased hands on time and that the sample number was not limiting. The 2-D DIGE showed that most of the HCPs were removed at the clarification and virus capture step. Column purification of HCPs with affinity to the anti-HCP pAbs increased the sensitivity of affinity analysis compared with Western blotting and opened the possibility of further analysis. The anti-HCP pAbs did not interact with proteins in the virus; simplifying analysis of process samples using SPR. 2-D DIGE analysis gave a direct study of the impurity profile with the advantage of independence from antibody performance.