Construction of a defective adenovirus vector expressing the pseudorabies virus glycoprotein gp50 and its use as a live vaccine.

The gene encoding the pseudorabies virus glycoprotein gp50 was cloned at the very left end of the genome of adenovirus type 5 to give a recombinant adenovirus (Ad-gp50) defective for the E1A gene. Ad-gp50 expressed high levels of gp50 in cells which either complemented (293 cells) or did not complement (Vero and HeLa cells) the E1A gene. Surprisingly, over an extended period, higher levels of gp50 were produced in HeLa cells which lack the E1A gene. Rabbits and mice inoculated with Ad-gp50 showed a strong antibody response against gp50. Some of them were protected from a virulent challenge with pseudorabies virus.