Two related glycoproteins (G and GNs ) encoded in the bovine ephemeral fever virus (BEFV) genome were expressed from recombinant vaccinia viruses (rVV). Both proteins were detected in lysates of rVV-infected cells by labelling with D-[6-3H]glucosamine or by immuno-blotting. The recombinant G protein (mol. mass 79 kDa) appeared slightly smaller than the native G protein but reacted with monoclonal antibodies directed against all defined neutralizing antigenic sites (G1, G2, G3a, G3b and G4). The recombinant G~s protein (mol. mass 90 kDa) was identical in size to the native GNs protein and failed to react by immunofluorescence with anti-G protein monoclonal or polyclonal antibodies. Antisera raised in rabbits against rVV-G or rVV-GNs both reacted strongly by immunofluorescence and immuno-electron microscopy with BEFV-infected cells. The G protein was localized intracellularly in the endoplasmic reticulum/Golgi complex and at the cell surface associated with budding and mature virus particles. The GNs protein also localized intracellularly in the endoplasmic reticulum/Golgi complex; however, at the cell surface it was associated with amorphous structures and not with budding or mature virions. Rabbits vaccinated with rVV-G developed high levels of antibodies which neutralized BEFV grown in either mammalian or insect cells. Cattle vaccinated with rVV-G also produced neutralizing antibodies and were protected against experimental BEFV infection. In contrast, rW-GNs vaccinated rabbits and cattle failed to produce neutralizing antibodies and, after challenge, BEFV was isolated from two-thirds of the vaccinated cattle.

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Sheep were immunized with a protective recombinant antigen (45W) from the cestode parasite Taenia ovis using three different vaccine delivery systems, either alone or in different combinations. The DNA encoding 45W was cloned into the expression plasmid pcDNA 3 and an ovine adenovirus to create nucleic acid and recombinant viral vector vaccines, respectively. Sheep received two vaccinations with various combinations of these two delivery systems and/or purified recombinant 45W protein in a conventional vaccine formulation containing Quil A as adjuvant (protein/Quil A vaccine). Sheep receiving two inoculations of either the nucleic acid or the recombinant adenovirus alone, demonstrated only low levels of 45W-specific antibody. However, immunization with either nucleic acid or recombinant adenovirus primed animals to mount an enhanced immune response after a subsequent vaccination with the protein/ Quil A vaccine. The most striking result was that sheep initially immunized with the nucleic acid vaccine and boosted with the recombinant adenovirus, mounted IgG1 responses > 65 fold higher than those of sheep receiving either vaccine alone. The level of antibody in these sheep was commensurate with that observed in animals vaccinated twice with the protein/Quil A adjuvanted vaccine. In both cases, host-protection from experimental challenge infection with T. ovis was obtained.