Lack of Evidence for lntertypic Recombinants in the Pathogenesis of Recurrent Genital Infections with Herpes Simplex Virus Type 1

Clinical observations indicate that herpes simplex virus type 1 (HSV-1) is significantly less likely than herpes simplex virus type 2 (HSV-2) to establish latency in (or reactivate from) sacral ganglionic tissue. In an effort to identify viral functions associated with latency, we analyzed HSV-1 isolates from three patients with established recurrent genital herpes and sought evidence of DNA sequences and proteins similar to those found in HSV-2. By restriction endonuclease cleavage patterns and by DNA hybridization analysis using either whole HSV-2 DNA or several cloned segments of HSV-2 DNA as probes, we found that the three HSV-1 isolates from patients with recurrent genital herpes showed no unusual homology to HSV-2 as compared with other HSV-1 isolates. Similarly, the proteins of these isolates could not be distinguished from those of other HSV-1 isolates and were distinct from those of HSV-2. At this level of resolution, there was no evidence to suggest that these recurrent genital HSV-1 isolates were intertypic recombinants, nor did they show any other unusual similarity to HSV-2.