Different batches of attenuated BRSV vaccine was examined for Safety and sterility. Identity of the BRSV vaccine was ensured using RT-PCR and its titration on MDBK cell line was done using IFAT.
The six evaluated vaccine batches gave 105.3, 105.2,105, 104,104.3 and 104.6 TCID50/ml titers respectively. Potency of the attenuated BRSV vaccines was evaluated in vaccinated calves using SNT and ELISA. Protective serum neutralizing antibody titer started at 3 weeks post vaccination for 1st, 2nd, and 3rd batches, and persisted till 18 weeks post vaccination, while the 4th, 5th and 6th batches did not give protective serum neutralizing antibody titer till the 4th week post vaccination. All the results of SNT were confirmed by using ELISA. It was concluded that evaluation of BRSV vaccines via RT-PCR and its titration on MDBK cell line using IFAT beside identification and safety tests, were more
economic, rapid and safe giving a good guide for the effectiveness of the vaccine used. |
