Comparable quality attributes of hepatitis E vaccine antigen with and without adjuvant adsorption-dissolution treatment

Abstract

Most vaccines require adjuvants for antigen stabilization and immune potentiation. Aluminum-based adjuvants are the most widely used adjuvants for human vaccines. Previous reports demonstrated the preservation of antigen conformation and other antigen characteristics after recovery from adjuvanted Hepatitis B and human papillomavirus vaccines. In this study, we used a combination of various physiochemical and immunochemical methods to analyze hepatitis E vaccine antigen quality attributes after recovery from adjuvants. All biochemical and biophysical methods showed similar characteristics of the p239 protein after recovery from adjuvanted vaccine formulation compared to the antigen in solution which never experienced adsorption/desorption process. Most importantly, we demonstrated full preservation of key antigen epitopes post-recovery from adjuvanted vaccine using a panel of murine monoclonal antibodies as exquisite probes. Antigenicity of p239 was probed with a panel of 9 mAbs using competition/blocking ELISA, surface plasmon resonance and sandwich ELISA methods. These multifaceted analyses demonstrated the preservation of antigen key epitopes and comparable protein thermal stability when adsorbed on adjuvants or of the recovered antigen post-dissolution treatment. A better understanding of the antigen conformation in adjuvanted vaccine will enhanced our knowledge of antigen-adjuvant interactions and facilitate an improved process control and development of stable vaccine formulation.

The development of a recombinant hepatitis E vaccine HEV 239

“…24,25,[28][29][30][31] Epitope mapping using cross-inhibitory ELISA, surface plasmon resonance biosensor chip based binding assay, and sandwich ELISA using HEV 239 specific mAbs were used to assure vaccine potency. 20,26,27 Overall, our findings showed that the antigen production process is robust and scalable in Hecolin Ò manufacturing. A successful and robust scale-up (i.e., 50-fold) in the production process (1.0 L, 10 L and 50 L) was demonstrated.…”

“…20,27 The most prominent band on the SDS-PAGE gel showed an apparent molecular weight of 29.4 kDa. All three lots exhibited similar MWs by MALDI-TOF-MS, with a mean MW of 25,561.5 § 1.5 Da (Table 1), which is consistent with the theoretical MW of HEV 239.…”

“…20 The thermal unfolding of the VLP antigen was analyzed using DSC by monitoring the T m values of all HEV 239 lots, all of which ranged from »75-76 C. These results showed good cross lot product consistency as reflected by the thermal stability of the recombinant protein antigen during heat-induced unfolding. 20,27 In addition, the propensity for the protein to aggregate under thermal stress was assessed using cloud point analysis. The heatinduced unfolding or aggregation profiles of the VLPs were highly comparable among all 6 lots, as determined by both DSC and cloud point ( Table 2).…”

“…17,24,25 A large panel of monoclonal antibodies (mAbs) against the HEV capsid protein were developed to improve the understanding of HEV virology and to analyze the CQAs of the vaccine during bioprocessing and in the lot release and stability testing. 14,15,20,26,27 Key epitopes of the particulate antigen were analyzed using a panel of murine anti-HEV mAbs against different epitopes, analogous to the approach used for other vaccines. 24,25,[28][29][30][31] Epitope mapping using cross-inhibitory ELISA, surface plasmon resonance biosensor chip based binding assay, and sandwich ELISA using HEV 239 specific mAbs were used to assure vaccine potency.…”

Prophylactic Hepatitis E Vaccines: Antigenic Analysis and Serological Evaluation

“…In addition, based on two-site binding, a highly sensitive and robust sandwich ELISA with the mAb 3A11 as the capture antibody and the mAb 8C11 as the detection antibody was developed for routine antigenicity testing. Comparable antigenicity of p239 pre-or post-dissolution treatment was determined, showing no change in epitopes after proper dissolution treatment with adjuvants [48]. Meanwhile, multiple lots of hepatitis E vaccines retained antigenicity after 36 months of storage [46].…”