Protective immunity against foot-and-mouth disease virus induced by a recombinant vaccinia virus

We report the construction of a recombinant vaccinia virus expressing the p recursor for the four structural proteins of FMD virus (FMDV) (P1) strain C 3Arg85 using a procedure for isolation of recombinant vaccinia viruses base d solely on plaque formation. Adult mice vaccinated with this recombinant v accinia virus elicited high titers of neutralizing antibodies against both the homologous FMDV and vaccinia virus, measured by neutralization assays. Liquid phase blocking sandwich enzyme-linked immunosorbent assays (ELISAs) using whole virus as antigen showed high total antibody titers against homo logous FMDV, similar to those induced by the conventional inactivated vacci ne. When ELISAs were carried out with heterologous strains A79 or O1Caseros as antigens, sera from animals vaccinated with the recombinant virus cross -reacted. Mice boosted once with the recombinant vaccinia virus were protec ted against challenge with infectious homologous virus. These results indic ate that recombinant vaccinia viruses are efficient immunogens against FMDV when used as a live vaccine in a mouse model. (C) 2000 Elsevier Science Lt d. All rights reserved.