G. Darby, H. Field, S. Salisbury
1981
Citations
2
Influential Citations
204
Citations
Quality indicators
Journal
Nature
Abstract
Acyclovir (9-[2-hydroxyethoxymethyl]guanine or ACV) is a nucleoside analogue with considerable potential for the treatment of herpes simplex virus (HSV) infections in man1,2. Two virus-coded enzymes are important in the mechanism of action of this drug: thymidine kinase (TK) which initiates its activation by converting it to the monophosphate3 and DNA polymerase whose action is inhibited by ACV triphosphate4. Changes in either gene may confer resistance5–7, but all reported mutations in the TK gene have resulted in failure of the resistant virus to induce appreciable levels of the enzyme. Such TK− mutants arise readily in tissue culture systems8,9 where the enzyme is non-essential for virus replication10, but in animals they show considerably reduced pathogenicity and neurovirulence7,11–14. We now describe the isolation of a resistant mutant which induces a TK of altered substrate specificity and we show that this virus retains pathogenicity for mice with only a slight attenuation of neurovirulence.