Immune Response of Foot and Mouth Disease Virus Type A87/irn Inactivated Vaccine by Gamma Irradiation on Guinea Pig in Iran

Foot and Mouth Disease (FMD) is the most contagious disease of cloven-hoofed animals, causing significant economical losses in livestock animals. In this study FMD Virus type A87/IRN was cultured and multiplied on BHK21 cells. The FMD virus was titrated by the Tissue Culture Infection Dose50 method (TCID50 /ml), the virus titration was 10. The FMD virus samples were irradiated and inactivated by gamma ray from a Co source at -20 °C. A safety test was done by the IBRS2 monolayer cell culture method, also antigenicity of irradiated and un-irradiated virus samples was studied by Complement Fixation Test. The Dose/Survival curve for irradiated FMDV was drawn. According to the curve and D10 Value factor, the optimum dose range for the inactivation of FMDV type A87/IRN and unaltered antigenicity was obtained (40-44 kGy). The inactivated virus samples by irradiation and ethyleneimine (EI) were formulated respectively as a vaccine with Al (OH) 3 gel and other substances. The vaccines were inoculated to Guinea pigs and the results of the Sero-Neutralization Test for both the normal vaccine and radio-vaccine showed protective titre after 8 months. The potency test of the inactivated vaccines was done, Protective Dose50 Value (PD50 Value) of the vaccines were calculated to be 7.06 and 5.6 for the inactivated vaccine by EI and gamma irradiation respectively.