Consequences of herpes simplex virus type 2 and human cell interaction at supraoptimal temperatures

The consequences of herpes simplex virus type 2 (HSV-2) and human embryonic fibroblast cell interaction at different temperatures (37, 40, and 42 degrees C) were investigated. Incubation at 37 or 40 degrees C was permissive for HSV-2 inhibition of host DNA synthesis, induction of virus-specific DNA replication, and infectious virus production. The amount of [methyl-3H]thymidine incorporated into viral DNA and the final yield of new infectious virus were significantly reduced at 40 degrees C compared to 37 degrees C. At 42 degrees C, detectable virus-specific DNA synthesis was totally blocked. Maximum stimulation of host cell DNA synthesis at 42 degrees C was measured after a multiplicity of infection of 0.5 to 1.0 PFU/cell. By autoradiography, data indicated that HSV-2 stimulates host cell chromosomal DNA synthesis. Stimulation of thymidine kinase activity with thermostability properties in common with a virus enzyme was detected during the first 24 h of infection at 42 degrees C, after 24 h the enhanced thymidine kinase activity had properties in common with host cell isozymes. The data obtained during this investigation indicated that stimulation of host cell DNA synthesis does not require viral DNA synthesis.