Production of PPR vaccine using attenuated strain in cell culture.

Peste des petits ruminants (PPR) is a contagious, fatal viral disease of sheep and goats which has been controlled in Iran for many years by rinderpest vaccine since the global rinderpest eradication program in Iran, the usage of rinderpest vaccine has been forbidden. Therefore,the application of a PPR homolog vaccine is vital in controlling and eradicating programs of the disease . For this purpose, PPR vaccine in limited rate and costly are imported and used only in high risk areas because of many difficulties in importation and proper transportation of this vaccine. In this study PPR vaccinal strain of Nigeria 75/1 was propagated in vero cell culture. It was identified by RT-PCR and titrated by Macro method. Master and working seeds were prepared from early passages in proper titer, then the vaccine pilot production was accomplished in two series. The bulks of vaccine were formulated with adequate amounts of preservative lactal and sucrose and lyophilized with proper cycle .Quality control tests were carried out in all stages of production. Clinical trials (safety and potency) of the vaccine were performed on 24 animals (lambs and kids) in 4 groups of 6 Groups 1,2 and 3 were inoculated with 0,1¡ 1 and 100 dose respectively. The last one as a control weren't inoculated. Clinical observations for 14 days and sero neutralization (SN) tests carried out 21 days after inoculations. Results showed that the highest virus titer in cell culture was 10 6¡8 TCID50 and vaccinal dose consists 10 3 TCID50 of the virus is a minimal immunogenic dose. Increase temperature and appearance of clinical signs weren't observed in all animal inoculants included 0¡1,1and 100 doses groups. Lowest and highest Antibody titers in lamb test groups and kid test groups were (1¡10, 1¡14) and (1¡10, 1¡52), respectively. In conclusion, this vaccine is completely safe and able to induce proper immunity in sheep and goats, although it induces higher titer of antibody in goats.