Abstract:
The effective control of foot-and-mouth disease (FMD) relies strongly on the separation of
susceptible and infected livestock or susceptible livestock and persistently infected wildlife, vaccination, and veterinary sanitary measures. Vaccines affording protection against multiple serotypes
for longer than six months and that are less reliant on the cold chain during handling are urgently
needed for the effective control of FMD in endemic regions. Although much effort has been devoted
to improving the immune responses elicited through the use of modern adjuvants, their efficacy
is dependent on the formulation recipe, target species and administration route. Here we compared and evaluated the efficacy of two adjuvant formulations in combination with a structurally
stabilized SAT2 vaccine antigen, designed to have improved thermostability, antigen shelf-life and
longevity of antibody response. Protection mediated by the Montanide ISA 206B-adjuvanted or
Quil-A Saponin-adjuvanted SAT2 vaccines were comparable. The Montanide ISA 206B-adjuvanted
vaccine elicited a higher SAT2 neutralizing antibody response and three times higher levels of systemic IFN-γ responses at 14- and 28-days post-vaccination (dpv) were observed compared to the
Quil-A Saponin-adjuvanted vaccine group. Interestingly, serum antibodies from the immunized
animals reacted similarly to the parental vaccine virus and viruses containing mutations in the VP2
protein that simulate antigenic drift in nature.
