Reliable identification of herpes simplex viruses by DNA restriction endonuclease analysis with EcoRI.

A simple procedure that permits the rapid identification of clinical isolates of herpes simplex virus (HSV, type 1 or type 2) on the basis of stable and type-specific differences in the EcoRI restriction endonuclease patterns of the HSV-1 and HSV-2 genomes was tested for reliability. Complete concordance was first obtained for 298 HSV isolates typed by standard laboratory procedures and by analysis of the DNA profiles. Two other HSV isolates showing intermediate biologic, immunologic, and/or biochemical properties were unambiguously identified by restriction endonuclease analysis of their genomes. Identical diagnostic results were also obtained by independent laboratories for another series of 150 HSV isolates after analysis of the EcoRI digestion products. As compared with other restriction enzymes, little intratypic variation in the DNA fragments selected for immediate identification of the isolates was found with EcoRI. The procedure used here, which does not require the purification and/or the radiolabeling of viral DNA, thus appears as most appropriate for the unambiguous typing of large numbers of HSV clinical isolates.