In vitro divergence of HSV-1 populations propagated in different cell lines.

To investigate how the structure of a virus population is influenced by the particular cell types in which the virus is propagated, laboratory populations of HSV-1 have been serially passaged onto a number of different cell lines, differing either in species or in tissue specificity. After a limited number of in vitro passages, several of the daughter virus populations have diverged in the expression of at least one phenotype, suggesting that different cell types have selected different variants contained in the parental virus population.