Compared to Aluminum Hydroxide Adjuvant, Montanide ISA ۲۰۶ VG Induces a Higher and More Durable Neutralizing Antibody Response against FMDV in Goats

Foot-and-mouth disease (FMD) has a high prevalence in cloven-hoofed animals. It is also highly contagious and remains a serious threat to livestock worldwide. Despite the widespread vaccination program in Iran, outbreaks of FMD continue to occur. Vaccination is one of the most effective methods of preventing FMD. The vaccines used in Iran are of the inactivated type and contain several serotypes. Since inactivated vaccines without adjuvants do not induce a high and durable antibody response, it is necessary to use adjuvants. Montanide ISA ۲۰۶ VG is a mineral oil-based adjuvant that produces a water-in-oil-in-water (w:o:w) emulsion in vaccine preparations. However, a large number of manufacturers in Iran and around the world still use alum adjuvant (with or without saponin) to produce the FMD vaccine. This study used Montanide ISA ۲۰۶ and alum adjuvants to administer the O۲۰۱۰ serotype of the FMD virus to goats. A total of six goats were divided randomly into three groups. Vaccines were administered subcutaneously twice, at a one-month interval. Blood sampling was done at different times, and the micro-neutralization method was used to measure the neutralizing antibody titer in each serum. Seven days after the second vaccination, the alum group’s antibody titer was higher but not statistically significant. However, from the ۲۸th day after the second injection until the end of the study, the Montanide ISA ۲۰۶ group’s antibody titer was significantly higher than that of the alum group. Six months after the second injection, the antibody titer in the ISA ۲۰۶ group remained at the peak level, while in the alum group, it decreased and reached the minimum protective level. Nine months after the second injection, the antibody titer remained at its peak level in the ISA ۲۰۶ group, whereas it dropped significantly in the alum group. Based on the findings, ISA ۲۰۶ VG is capable of generating long-term humoral immunity in goats against the FMD serotype O۲۰۱۰ and could replace aluminum hydroxide adjuvants in FMD vaccine preparations.