Complementation with ts mutants of herpes simplex virus.

Tests to detect complementation between ts mutants of herpes simplex virus types 1 and 2 infectious centre and yield of virus assay were investigated. Progeny analysis of both intratypic and intertypic complementation showed a considerable proportion of recombinant or ts+ virus in the progeny; this was more marked in the infectious centre tests. Virus of intermediate temperature-sensitivity was produced in intratypic as well as intertypic complementation. Reduction in the input multiplicity of one of the two mutants in the test to extremely low levels did not prevent complementation, suggesting that non-infectious particles probably contribute to complementation. Demonstration of virus DNA synthesis in mixedly-infected cells at the non-permissive temperature was used to detect complementation between DNA-negative mutants.