Inactivation of foot and mouth disease virus for vaccine production

Inactivation is the loss by a virus of ability to reproduce and infect susceptible animals while retaining its antigenic properties. In this paper, the effectiveness of aminoethylethanolamine when used as an FMDV inactivant is shown. The inactivation rates under selected parameters, effect of aminoethylethanolamine on virus stability during inactivation and on vaccine immunogenicity after storage at 2–8 °С were determined. The method for calculation of 50% aminoethylethanolamine inactivating concentration (IC50) which enables to determine quality parameters of the virus-containing suspension, to compare the inactivating agent activities and their ability to ensure the vaccine innocuity within the given period of time is presented. It was established that IC50 for purified and non-purified virus-containing suspensions was identical (0.0045%), and its safety after 12 h of inactivation was one TCID50 per 109–1011 L of the virus containing suspension. It was also found that double increase in inactivation time increased the virucidal activity of aminoethylethanolamine by a factor of 1.8 for serotype O and 2.4 for serotype A. At the same time, the removal of cell debris had no significant effect on the inactivation process. Aminoethylethanolamine does not destroy 146S virus particles and it was confirmed by immunogenicity testing of the vaccines during storage. This means that 15% aqueous solution of aminoethylethanolamine, manufactured by Russian Company OOO “BIOKHIMRESURS” (Vladimir) complies with high quality standards. Immunogenicity test of bivalent FMD vaccine for cattle by challenging demonstrated that its potency was 10.08 protective doses per 2 cm3 of the vaccination dose.