Fusion Proteins with Multiple Copies of the Major Antigenic Determinant of Foot-and-Mouth Disease Virus Protect both the Natural Host and Laboratory Animals

Abstract

SUMMARYProteins consisting of one, two or four copies of the amino acid sequence 137 to 162, which contains the major immunogenic site of VP1 of foot-and-mouth disease virus, attached to the N-terminus of fl-galactosidase have been expressed in Escherichia coli cells. In guinea-pigs the protein containing one copy (P71) of the viral determinant elicited only low levels of neutralizing antibody whereas protective levels were elicited by the proteins containing two (P72) or four (P74) copies of the determinant. Single inoculations of the P72 and P74 proteins containing as little as 2 ~tg or 0-8 gg of peptide respectively were sufficient to protect all the animals against challenge infection. Moreover, the equivalent of 40 gg of peptide in P74 protected pigs against challenge infection after one inoculation.

Heterotypic Lymphoproliferative Response in Pigs Vaccinated With Foot-and-mouth Disease Virus. Involvement of isolated Capsid Proteins

“…Consequently, considerable effort is being focused on the development of new, safer and broadly protective vaccines (for review, see Brown, 1989). Immunization with VP1 and fragments of this protein, including synthetic peptides, elicited neutralizing antibodies and resulted in natural hosts becoming protected against virus challenge (Laporte et al, 1973;Bachrach et al, 1975;Kleid et al, 1981 ;Bittle et al, 1982;Strohmaier et al, 1982;Francis et al, 1985;DiMarchi et al, 1986;Broekhuijsen et al, 1987); however, the immunity induced was poor. The immunogenicity of synthetic peptides modelled after the main antigenic sites of VP1 was increased when fused with hepatitis B virus core protein (Clarke et al, 1987).…”

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

“…Our results showed that the most immunogenic of the TrpE-FMDV fusion proteins was TrpE-dCN (Table 1). VP1 sequences in TrpE~tCN are also present in TrpE-VP1 and TrpE-CN, therefore it is likely that the increased immunogenicity of the former resulted from either the presentation of multiple copies of the VP1 epitope (Broekhuijsen et al, 1987;Kleid et al, 1985) or an enhancing effect of linking amino acids 200 to 213 and 141 to 158 by a diproline spacer (DiMarchi et al, 1986). It has been shown that the contribution of peptide 200-213 to the immunogenicity of the domain is not due to the induction of antibodies directed against its sequence but rather to the highly immunogenic configuration assumed by such a 40 residue peptide (Doel et al, 1988).…”

Serological Prospects for Peptide Vaccines against Foot-and-Mouth Disease Virus

“…The antibody preparations to the (137-162)4-/~-galactosidase construct allowed this hypothesis to be tested. The fusion protein is highly immunogenic (Broekhuijsen et al, 1987) and its polyclonal antiserum and MAb had very similar specificities, which were intermediate between those of the 135-160C and 141-160C peptide antisera. ELISA titrations indicated that the MAb bound to a linear epitope which was located around amino acids 140 to 143.…”

“…The major problem remaining in the development of peptide vaccines against FMDV is that none so far reproducibly elicits a high-titre antibody response in cattle. The use of multiple copies of epitopes enhances immunogenicity (Broekhuijsen et al, 1987), and expressing the peptide as a fusion protein on the surface of hepatitis B core antigen particles enhances it by many orders of magnitude (Clarke et al, 1987b), although the latter preparation has yet to be evaluated in cattle. From studies of the responses to FMDV peptides in different strains of mice, Francis et al (1987b) demonstrated that restriction of these responses occurred at the T cell level, and this could be overcome with peptides which incorporated both the specific B cell epitope and 'foreign' T helper cell epitope sequences.…”

“…Antisera to each antigen were collected from five guinea-pigs and pools of an equal volume were used for specificity testing. Antisera raised against a fusion protein consisting of four copies of the 137--162 sequence linked to a/J-galactosidase molecule (Broekhuijsen et al, 1987) and a neutralizing murine monoclonal antibody (MAb) to this protein, produced at the TNO Laboratory, Rijswijk, The Netherlands, were also used.…”