These tests assay serum for the presence of
either neutralising antibodies or antibody to whole virus by
ELISA and they cannot distinguish carrier animals from uninfected
vaccinates. This serious shortcoming prevents detection
of asymptomatic carrier animals that can be found
in vaccinated herds. Consequently, OIE regulations specify
that vaccinated animals must be destroyed before a country
can regain disease-free status [1]. A synthetic subunit vaccine
for FMDV has long been sought as an antigenic marker
vaccine and for the safety advantages of a product that does
not use virus in its manufacturing process.
The prominent G–H loop of the VP1 capsid protein of
FMDV, spanning residues 134–158, has been identified
as the major immunogenic site for neutralising antibodies
[2–5]. This has formed the basis for the peptide approach
to vaccination against FMD [3,6,7]. The successful protection
of susceptible hoofed species by administration of
G–H loop synthetic peptides has not been achieved due
to the limited immunogenicity of the peptides. The VP1
region itself lacks T helper (Th) cell epitopes for promiscuous
recognition by porcine and bovine MHC alleles [8,9].
Thus, a fully protective VP1 loop peptide vaccine needs