Veterinary World (Sep 2013)
Preparation of Foot and Mouth Disease trivalent vaccine type A, O, SAT2 with determination of the Guinea pig protective dose 50 (GPPD50)
Abstract
Aim: To determine the minimal effective dose of Foot and Mouth disease (FMD) serotypes (A, O, SAT2) according toantigenic content (146S) in order to produce a potent trivalent FMD vaccine.Materials and Methods: Monovalent ISA 206 vaccines were prepared with 3 final concentration of 146S (1.6, 2.2, 2.8μg/dose). The vaccine potency was evaluated by the determination of guinea pig protective dose 50 (GPPD )for each 50concentration of 146S for each type of FMD monovalent vaccine where a fourfold dilution of the vaccines was constructedand each dilution was inoculated as 0.5 ml S/C in each of 5 guinea pigs.Results: The obtained results revealed that by using 1.6 μg of 146S for type O Pan Asia-2, AIran O5 and SAT/EGY/2012, theGPPD was 40.4, 19.75 and 31.6 respectively, while the use of 2.2 μg of 146S resulted in GPPD 78.6, 78.6 and 105.8 for the 50 50three types respectively, and by using 2.8 μg of 146S resulted in GPPD 161.7, 105.8 and 161.7 for the three subtypes (A, O, 50SAT2) respectively. So it is clear that the lowest 146S dilution inducing good protection (more than 72 GPPD ) was 2.2 μg for 50each serotype of used FMD monovalent vaccines. Depending on this result, the trivalent vaccine was formulated as 2.2 μg of146S payload from each virus type/dose with equal volume of montanide ISA206 oil as adjuvant. For more confirmation theprepared trivalent vaccine potency was evaluated by Guinea pig protective dose 50 which was found to be 88 GPPD .Also 50mean SNT antibody titer was detected in serum of the test Guinea pigs 1.56, 1.68 and 1.68 log /ml against FMDVserotype O 10Pan Asia-2, AIran O5 and SAT/EGY/2012 respectively in a higher level than the recommended protective titer (PT=1.2). Alsofor further confirmation the formulated trivalent vaccine which contain 2.2 μg/serotype/dose were evaluated in cattle tomeasure the antibody titer against the three serotypes and the antibody against the three serotypes were found to be higher thanthe recommended titer (1.5) which extended for 32 WPVand these results came in parallel manner to the GPPD and antibody 50titer of the Guinea pigs of the prepared trivalent vaccine with 146S (2.2 μg/serotype/dose).Conclusion: It could be concluded that the minimum content of antigenic 146S of FMDVserotype O pan Asia, AIran O5 andSAT2/EGY/2012 should not be less than 2.2 μg/dose/ from each serotype in the trivalent vaccine aiming to induce thepermissible protection in vaccinated livestock.
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