Immune response in pigs to Aujeszky's disease viruses defective in glycoprotein g1 or gX

Abstract

Two Aujeszky's disease virus glycoprotein genes, gX and gl, have been used to produce deletion mutants which have then been developed into vaccines. These deletions then allow differentiation between pigs infected with wild type virus and those given the vaccine. It is not clear whether the glycoproteins encoded for by these genes are needed to induce a full protective immune response, in which case deletion mutants would suffer from lack of potency. To test this, commercially available Aujeszky's virus vaccines which lacked either gX or gl were compared and isogenic constructs were made which differed only in the absence or presence of gX and, or, g1. These constructs and vaccines were used to vaccinate the natural host of Aujeszky's disease, the pig, and potency was measured using challenge with wild type virus. In all cases vaccines which lacked gl performed significantly less well than those in which gl was present, whereas deletions of gX had no significant effect on vaccine performance.