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Aim: To determine the minimal effective dose of Foot and Mouth disease (FMD) serotypes (A, O, SAT2) according to antigenic 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, 2.8 µg/dose). The vaccine potency was evaluated by the determination of guinea pig protective dose 50 (GPPD )for each 50 concentration of 146S for each type of FMD monovalent vaccine where a fourfold dilution of the vaccines was constructed and 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, A Iran O5 and SAT/EGY/2012, the GPPD 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 50 three 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, 50 SAT2) respectively. So it is clear that the lowest 146S dilution inducing good protection (more than 72 GPPD ) was 2.2 µg for 50 each serotype of used FMD monovalent vaccines. Depending on this result, the trivalent vaccine was formulated as 2.2 µg of 146S payload from each virus type/dose with equal volume of montanide ISA 206 oil as adjuvant. For more confirmation the prepared trivalent vaccine potency was evaluated by Guinea pig protective dose 50 which was found to be 88 GPPD .Also 50 mean SNT antibody titer was detected in serum of the test Guinea pigs 1.56, 1.68 and 1.68 log /ml against FMDV serotype O 10Pan Asia-2, A Iran O5 and SAT/EGY/2012 respectively in a higher level than the recommended protective titer (PT=1.2). Also for further confirmation the formulated trivalent vaccine which contain 2.2 µg/serotype/dose were evaluated in cattle to measure the antibody titer against the three serotypes and the antibody against the three serotypes were found to be higher than the recommended titer (1.5) which extended for 32 WPV and these results came in parallel manner to the GPPD and antibody 50 titer 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 FMDV serotype O pan Asia, A Iran O5 and SAT2/EGY/2012 should not be less than 2.2 µg/dose/ from each serotype in the trivalent vaccine aiming to induce the permissible protection in vaccinated livestock.

Foot-and-mouth disease (FMD) vaccine does not afford early effective protection until adaptive immune protection caused by the vaccination occurs. Therefore, an alternative prophylactic application of antiviral agents for inhibition of the FMD virus is needed, and this is the scope of this study. In this study, we tested nine adamantane-pyrazole derivatives that could exhibit antiviral activity against FMDV infection either in vitro through baby hamster kidney cells (BHK-21 cells) infected with FMD virus serotypes O pan Asia. Cytotoxicity Concentration 50 (CC 50) activity of pyrazole derivatives (1, 2, 3, 4, 5a,b, 6a-c) were detected on BHK-21 cells and ranged between 500 to 3000µg/ml. Inhibitory Concentration 50 (IC 50) on BHK-21 was achieved only for the most promising three derivatives 6a-c and exhibited an antiviral activity with a therapeutic index of 30, and that was reflected on the antiviral activity response in baby mice with different concentrations where a concentration of 50 µg/ml for pyrazole derivatives 6a and 6c compounds and 40 µg/ml for bis-tolyl pyrazole 6b that achieve 100% protection and this results was as effective as 50 µg/ml of amantadine. Specifically, diaryl pyrazole derivatives 6a-c that protected for six days following FMDV challenge. These results suggested that pyrazole derivatives 6a-c could be used as an effective antiviral agent against FMD virus infection. Molecular docking simulation of the target compounds 6a-c had good binding energy and the tested compounds recommended being an excellent 3C protease inhibitor compared to Amantadine and Ribavirin. These findings may explain the antiviral activity of the target compounds.

Aim:The present work deals with different methods for foot and mouth disease virus (FMDV) inactivation for serotypes O/pan Asia, A/Iran05, and SAT-2/2012 by heat, gamma radiation, and ultraviolet (UV) in comparison with the traditional methods and their effects on the antigenicity of viruses for production of inactivated vaccines.Materials and Methods:FMDV types O/pan Asia, A/Iran05, and SAT-2/2012 were propagated in baby hamster kidney 21 (BHK21) and titrated then divided into five parts; the first part inactivated with heat, the second part inactivated with gamma radiation, the third part inactivated with UV light, the fourth part inactivated with binary ethylamine, and the last part inactivated with combination of binary ethylamine and formaldehyde (BEI+FA). Evaluate the method of inactivation via inoculation in BHK21, inoculation in suckling baby mice and complement fixation test then formulate vaccine using different methods of inactivation then applying the quality control tests to evaluate each formulated vaccine.Results:The effect of heat, gamma radiation, and UV on the ability of replication of FMDV “O/pan Asia, A/Iran05, and SAT-2/2012” was determined through BHK cell line passage. Each of the 9 virus aliquots titer 108 TCID50 (3 for each strain) were exposed to 37, 57, and 77°C for 15, 30, and 45 min. Similarly, another 15 aliquots (5 for each strain) contain 1 mm depth of the exposed samples in petri-dish was exposed to UV light (252.7 nm wavelength: One foot distance) for 15, 30, 45, 60, and 65 min. Different doses of gamma radiation (10, 20, 25, 30, 35, 40, 45, 50, 55, and 60 KGy) were applied in a dose rate 0.551 Gy/s for each strain and repeated 6 times for each dose. FMDV (O/pan Asia, A/Iran05, and SAT-2/2012) were inactivated when exposed to heat ≥57°C for 15 min. The UV inactivation of FMDV (O/pan Asia and SAT-2) was obtained within 60 min and 65 min for type A/Iran05. The ideal dose for inactivation of FMDV (O/pan Asia, A/Iran05, and SAT-2/2012) with gamma radiation were 55-60 and 45 kGy, respectively. Inactivation of FMDV with binary was 20, 24 and 16 hr for O/pan Asia, A/Iran05, and SAT-2/2012, respectively while inactivation by (BEI+FA) was determined after 18, 19 and 11 hr for O/pan-Asia, A/Iran 05, and SAT-2/2012, respectively. The antigenicity of control virus before inactivation was 1/32, it was not changed after inactivation in case of gamma radiation and (BEI+FA) and slightly decrease to 1/16 in case of binary and declined to 1/2, 1/4 in case of heat and UV inactivation, respectively. The immune response induced by inactivated FMD vaccines by gamma radiation and (BEI+FA) lasted to 9 months post-vaccination, while the binary only still up to 8 months post-vaccination but heat and UV-inactivated vaccines were not effective.Conclusion:Gamma radiation could be considered a good new inactivator inducing the same results of inactivated vaccine by binary with formaldehyde (BEI+FA).