A simple and practical method for typing and strain differentiation of herpes simplex virus using infected cell DNAs

A simple and practical method for typing and strain differentiation of herpes simplex virus (HSV) isolates, based upon analysis of the restriction endonuclease cleavage patterns of viral DNAs, was established by using unlabeled infected cell DNAs. The preparation of infected cell DNA is technically easier than that of purified viral DNA or of radiolabeled viral DNA. The method provides a powerful and practical tool for epidemiological and clinical studies of HSV infection, which can be performed in most diagnostic laboratories. In order to select suitable restriction endonucleases for the study of HSV isolates, the cleavage patterns of viral DNAs (strains MacIntyre, HF, UW-268, and SAV) with 12 enzymes were analyzed. Several enzymes, Bam HI, Kpn I, Pst I, Sal I, Sst I, and Xho I, were found to be useful for both typing and strain differentiation. With this method, HSV isolates from different individuals and from the same individual were analyzed by digestion of their infected cell DNAs with Bam HI. Six isolates from epidemiologically unrelated individuals were readily typed and differentiated from each other. Three isolates from the same individual showed very similar patterns. However, there was a small degree of difference between the first two isolates and the third isolate.