Effect of herpes simplex virus on the DNA of human papillomavirus 18

Some types of human papillomaviruses (HPV) appear to be associated with carcinoma of the cervix or other tissues, but patients infected with HPV do not necessarily develop carcinoma. Some epidemiological studies of risk factors for cervical carcinoma have indicated the involvement of herpes simplex virus (HSV). To study the effect of HSV on the genome of HPV, total DNAs were extracted and analyzed after HeLa cells, or A431 cells, transiently transfected with HPV18 DNA, were infected with HSV-1 or -2 for 24 hours. In HeLa cells, integrated HPV18 DNA was amplified almost threefold. In A431 cells, HPV 18 DNA fragments, sensitive to the restriction enzyme Mbo I, indicated newly replicated DNA. Replication intermediates were detected when the DNA was resolved by two-dimensional gel electrophoresis. This study showed that HSV caused some amplification of HPV and indicated the possibility of HSV involved in the integration and amplification of HPV in host cells.