In-situ and sensitive stability study of emulsion and aluminum adjuvanted inactivated foot-and-mouth disease virus vaccine by differential scanning fluorimetry analysis

Adjuvants are important to enhance the antigens immunogenicity, but may also alter the structures of antigens. Currently off-line methods for adjuvants induced antigen alteration suffer from incomplete release and possible structural alteration of antigens. Here we investigated the differential scanning fluorimetry (DSF) as an in-situ and high-throughput strategy to analyze the stability of inactivated foot-and- mouth disease virus (iFMDV), known as 146S, in three representative adjuvants including aluminum hydroxide (AH), oil-in-water (O/W) emulsion, and water-in-oil (W/O) emulsion. Under optimized DSF conditions, the T-m referring to 146S dissociation can be detected in all three adjuvants. Using SYBR Green II as fluorescent dye enables detection of iFMDV as low as 5 mu g/mL. By comparing the T-m in different pH, three adjuvants showed different effects on 146S. Screening for excipients was successfully conducted using DSF. Sugars and glycerol increased the T-m of iFMDV in all three adjuvants, but to different degree. The stabilization by 20% (w/v) sucrose and glycerol was further verified by differential scanning calorimetry (DSC) and high performance size exclusion chromatography (HPSEC). DSF is proved also applicative for low-purity iFMDV and pre-adjuvanted iFMDV vaccines. In summary, the DSF can be a powerful tool in formulation study and vaccine quality control for inactivated virus vaccines. (C) 2020 Elsevier Ltd. All rights reserved.