Calcium Chloride Treatment Enhances Antigen Production in Foot-and-Mouth Disease Vaccines for Serotypes SAT1 and SAT3.

Foot-and-mouth disease (FMD) is a highly contagious viral infection causing acute and severe vesicular lesions in cattle and pigs, which has prompted global vaccination policies. This study presents a technique for enhancing antigen yield in SAT1 BOT and SAT3 ZIM by treatment with calcium chloride (CaCl 2 ). We tested changes in cell viability in BHK-21 suspension cells treated with varying concentrations of CaCl 2 . The optimal CaCl 2 concentration was determined based on antigen yield. The timing of CaCl 2 supplementation relative to FMD virus inoculation was tested. Finally, the optimal medium for antigen production was identified. We observed a concentration-dependent decrease in BHK-21 cell viability at >7.5 mM CaCl 2 . A CaCl 2 concentration of 3 mM yielded the most antigens. CaCl 2 supplementation relative to FMD virus infection was optimal 2 h before or with viral inoculation. CD-BHK 21 medium supplemented with CaCl 2 was the most productive medium. Specifically, SAT1 BOT and SAT3 ZIM showed improved antigen production in CD-BHK 21 medium with 3 mM CaCl 2 , while Provero-1 and Cellvento BHK-200 media showed no significant enhancement. Overall, CaCl 2 supplementation enhanced FMD antigen productivity. This study provides a useful framework for enhancing antigen production efficiently in the FMD vaccine industry.