Background and Aims: Foot-and-Mouth Disease (FMD) is a highly contagious infectious disease of livestock which has made a barrier to hygiene causing severe loss in livestock and their products. The aim of this study was the assessment of antibody response against foot and mouth disease virus  types A13, A15 , O2010, after injection of FMD vaccine candidate produced by Razi Institue.
Materials and Methods: twenty non-vaccinated healthy calves were purchased and their health was evaluated. In order to ensure the absence of antibodies against FMD virus of all types, the blood of animal was sampled and subjected to serum neutralization test (SNT).
The SNT method was performed by the micro-neutralization test. Serum samples were tested before and after vaccination. Six wells of dilutions, 1/8 to 1/256 of serum were prepared and after adding the FMD virus they were incubated and then were added to the cell culture. After 48 hours the CPE was checked.
Results: The mean serum titers of antibodies against all three viral type Average A13, A15 and O2010 prior to vaccination was equal to 0.6. One week after the injection, the antibody titer increased especially against A15 in a significant difference (p value=0.017) compared to two other types. The serum antibody titers increase in the three virus types were continued one month after injection. Since then the A13 and A15 type antibody titer underwent increasing but declined against O2010 type. In the second month after the injection, the titer against A13 and A15 remained in stationary state and declined against O2010 type. The statistical analysis showed that the antibody level against the viral types was significantly different in 7 days, 1, 2, 4, 6 and 7 months after the injection.
Conclusions: The FMD vaccine produced by Razi institute showed the ability to protect animals become dependent on test conditions, the type O2010 for 6 months and for the type A15 and A13 for 7 months after vaccination.