Vaccine potential of a live avirulent herpes simplex virus.

We previously described a herpes simplex intertypic recombinant that is completely and specifically non-neurovirulent following intracranial inoculation. In this report the vaccine potential of this mutant (RE6) is analyzed. It is shown that RE6 replicates to wild type levels at the peripheral site of inoculation (the mouse footpad) but, unlike its virulent parental strains, does not replicate to detectable levels in lumbosacral ganglia. A single vaccination with RE6 is sufficient to completely protect mice against subsequent challenge with either HSV-1 or HSV-2. However, this agent establishes latent infections efficiently, and is fully neurovirulent for newborn mice.