Nature of the Antibody Response to the Foot-and-Mouth Disease Virus Particle, its 12S Protein Subunit and the Isolated Immunizing Polypeptide VP1

Abstract

SUMMARYInoculation of inactivated 146S foot-and-mouth disease virus particles into guineapigs elicited the formation of neutralizing antibody and the serum had a 10-fold higher titre in radioimmunoassay (RIA) with 146S particles than with the 12S virus subunit. In contrast, a single inoculation of the 12S subunit or the isolated polypeptide VP1 elicited the formation of antibody having a much lower titre in RIA with the 146S particle than with the 12S subunit and low or undetectable neutralizing activity. However, sera from guinea-pigs given two or more inoculations of the 12S subunit or VP1 had neutralizing activity. The level in the anti-VP1 serum was lower than that in the anti-12S serum and both were much lower than that in animals receiving two inoculations of the 146S particle. The neutralizing activity elicited by the three antigens was absorbed by the homologous antigen. In contrast, neither the 12S subunit nor VP1 absorbed the anti-146S neutralizing antibody and VPI did not absorb the anti-12S subunit neutralizing antibody. However, the 12S subunit partly absorbed the neutralizing activity elicited by VP 1. The results are compatible with a model in which the 146S particle elicits a spectrum of neutralizing antibodies which are completely absorbed by the homologous particle but only partially by the 12S subunit or VP1. The results are discussed in relation to the structural features required for the production of neutralizing antibody.

Qualitative and Quantitative Differences in the Immune Response to Foot-and-Mouth Disease Virus Antigens and Synthetic Peptides

“…This indicates that the amino acid sequence 130 to 160 within VP1 is not recognized by the peptide-primed immune system when it is present on intact but denatured VP1. This is in agreement with published data on the antigenicity and immunogenicity of this viral protein (Bachrach et aL, 1975;Cartwright et al, 1982;Meloen & Barteling, 1986a, b). Low level priming by peptide for the 12S virus subunit suggests that the major epitope may adopt a more linear conformation on the sub-viral particles.…”

An Epitope Located at the C Terminus of Isolated VP1 of Foot-and-Mouth Disease Virus Type O Induces Neutralizing Activity but Poor Protection

“…In contrast, a single dose of vaccine containing a few ~tg of intact virus particles is sufficient to induce protection. A possible clue to this observation was provided by earlier results indicating that the neutralizing ability of anti-VP1 sera differed qualitatively from that of sera induced by intact virus (Meloen & Briaire, 1980;Cartwright et al, 1982). Moreover anti-VP1 type O1 sera were shown to neutralize both serotypes O1 and A10 in contrast to anti-140S sera which do not cross-neutralize heterologous serotypes.…”

Characterization and Specificity of Humoral Immune Responses to Theiler's Murine Encephalomyelitis Virus Capsid Proteins

“…Studies employing isolated capsid proteins have yielded similar results. Poliovirus and foot-and-mouth disease virus (FMDV) bear neutralization epitopes on VP1, as immunization with purified VP1 protects animals from live virus challenge (Bachrach et al, 1975 ;Blondel et al, 1982;Cartwright et al, 1982;Chow & Baltimore, 1982;Dernick et al, 1983;Emini et al, 1983;Laporte et al, 1973;Meloen et al, 1979;van der Marel et al, 1983). Similarly, only VP 1 from Mengo virus is capable of generating neutralizing antibody as measured by a plaque reduction assay (Lund et al, 1977).…”