Deletion mutant of a herpesvirus and vaccine containing said virus

Claim 1

Live deletion mutant of a herpesvirus, the genome of which differs from the genome of the parental strain which consists of about 160,000 nucleotide pairs and is characterized by a restriction map typical for Pseudorabies virus DNA, for example by the restriction map of figure 1, in which the rectangles represent inverted repeats and the vertical lines represent the cleavage sites of the restriction endonucleases HindIII, Kpnl, BamHI and BglII, which genome comprises a small unique sequence U s having a restriction map typical for the small unique sequence of Pseudorabies virus DNA, for example the restriction map depicted in figure 2, in which the arrows represent the cleavage sites of the restriction endonucleases indicated in figure 2, by the presence of one or more of the following deletions: (a) A deletion in the inverted repeats situated between the cleavage sites of KpnI (between fragment E, or fragment H, respectively, and fragment K +.M) and the cleavage sites of BamHI (between BamHI fragments 5 and 8); (b) A deletion in the region which is hatched in the restriction map of the small unique sequence (figure 2); (c) A deletion in the thymidine kinase gene.