Comparison of different inactivation methods on the stability of Indian vaccine strains of foot and mouth disease virus

- Inactivation of FMDV is a critical step in the FMD vaccine preparation.
- Efficiency of BEI, BEI + FA and BEI + GTA in the inactivation of FMDV is evaluated.
- BEI + FA inactivant combination out performed in the inactivation of FMDV.
- No change in the 146S content of the serotypes studied during inactivation process.
- A region of 1D gene of FMDV could be amplified from inactivated samples.

In this study, the efficiency of binary ethyleneimine (BEI) in combination with formaldehyde (FA) and glutaraldehyde (GTA) in inactivating the Indian FMDV vaccine strains is compared. The acceptable safety of virus inactivation was faster and the inactivation rates were increased many-folds with combination of inactivants than BEI alone. FMDV A was inactivated rapidly than the other two serotypes with BEI + FA combination. Inactivation plots were linear for all the serotypes irrespective of inactivation process. Further, the integrity studies on 146S using serotype specific ELISA indicated no significant change in the antigenic mass of all the serotypes throughout the inactivation process. However, the loss of 146S antigen occurred in the subsequent steps of downstream processing. Further, the studies on intactness of viral RNA using real time PCR indicated the amplification of 1D gene sequences in all the preparations of timed samples irrespective of serotypes/inactivation process. Further, inactivated virus preparation (146S) was more stable at lower temperatures for all the serotypes/inactivation process. Among the combinations of inactivants, BEI + FA out performed compared to BEI + GTA and BEI in terms of inactivation rates, 146S yield and its storage stability, irrespective of the serotypes.