Protection conferred by TrpE fusion proteins containing portions of the C-terminal region of capsid protein VP1 of foot-and-mouth disease virus

Abstract

Major immunogenic sites of foot-and-mouth disease virus (FMDV) have been mapped to the C-terminal third of capsid protein VP1; we studied the immunogenicity of a series of TrpE-FMDV fusion proteins containing this region of FMDV strain O1 Campos. Fusion protein TrpE-dCN, which contains a dimer of VP1 amino acid sequences consisting of amino acids 200 to 213 linked by a diproline spacer to amino acids 141 to 158 (200-213 ~P-P-G ~ 141-158), induced the best response. A single inoculation of guinea-pigs with 100 ~tg TrpE-dCN elicited high levels of neutralizing antibodies and protected all the animals against challenge infection with homologous virus. Although the closely related FMDV strains O1 Campos and O1 Caseros induced high levels of cross-protection, TrpEdCN-vaccinated guinea-pigs were poorly protected against challenge infection with heterologous FMDV strain O1 Caseros. Nucleotide sequence analysis revealed that amino acid differences at residues 149 and 152 were critical for the induction of crossprotection and that neutralizing epitopes not present in TrpE-dCN are likely to be responsible for conferring a high level of cross-protection between FMDV strains O1 Campos and O1 Caseros.

Biosensor characterization of antigenic site A of foot-and-mouth disease virus presented in different vector systems

“…This amount of immunogen is in the same range of that used by other authors (i.e. 4,25,26,28) although the number of injections given to each animal was higher in our case. High ELISA titers were obtained in all guinea pig sera, the highest titers being obtained when animals were immunized with peptide A coupled to OVA and the lowest titers with animals which received M275VP1.…”

Extensive antigenic diversification of foot-and-mouth disease virus by amino acid substitutions outside the major antigenic site

“…However, other evidence suggests that site A may not suffice to evoke a broadly protective response. Unlike a whole-virus vaccine, a recombinant vaccine based on those same antigenic regions of FMDV O~ Campos did not protect against O~ Caseros, whicl'/differed in two amino acids within site A (Giavedoni et al, 1991). Although a different presentation of these sites in the recombinant and the peptide vaccines may account for this, an alternative interpretation of this observation is the participation of regions other than sites A and C in the response to whole-virus vaccines.…”

Biosensor characterization of antigenic site A of foot-and-mouth disease virus presented in different vector systems

“…ELISA data reported in the literature are rarely comparable because different reagents and protocols are used in different laboratories and the results are often expressed in different ways. For example, ELISA titers of FMDV antisera have been reported as the negative logarithm of the serum dilution that gave a response twice that of the background value [25], as an end point dilution [28], as the reciprocal of the serum dilution binding to 50% of 5 pmol of antigen [7] and as the highest serum dilution that gave an absorbance of 1.0. ([13]; this work).…”

“…Another approach for presenting specific epitopes to the immune system consists in expressing peptides as fusion proteins using recombinant technology. The peptide can be fused at one end of the vector protein [25–28] or it can be inserted within the protein [29–31]. In the case of FMDV, tandem repeats of the site A sequence fused to the N‐terminus of β‐galactosidase, when injected in laboratory animals or natural hosts, were able to elicit protection against the virus [25].…”