Strains of varicella-zoster virus resistant to 1-beta-D-arabinofuranosyl-E-5-(2-bromovinyl)uracil

Abstract

Strains of varicella-zoster virus resistant to 1-p-D-arabinofuranosyl-E-5-(2-bromovinyl)uracil (BV-araU) were isolated from varicella-zoster virus-infected Vero cells which were pulse-treated with 5-iododeoxyuridine or 5-bromodeoxyuridine or both and then treated with BV-araU. These BV-araU-resistant strains (BVaraUr) could not be isolated from varicella-zoster virus-infected cells treated with BV-araU alone and had reduced viral thymidine kinase activity. Two offive BV-araUr strains were also resistant to 5-icdodeoxyuridine and 5-bromodeoxyuridine, whereas other BV-araUr strains were relatively susceptible to these drugs.All clones from the BV-araUr strain were susceptible to 1-p-D-arabinofuranosylcytosine and phosphonoacetic acid, but 7 of 10 clones from the BV-araUr strain were resistant to 1-p-D-arabinofuranosyladenine. The possible mechanisms of induction of BV-araU resistance are discussed.Molecular analysis of the viral genome and its relation to viral replication has been extensively studied in herpes simplex virus (HSV), Epstein-Barr virus, and cytomegalovirus of the family Herpetoviridae (8,10,12,20,22,25,30). Dubbs ahd Kit (9) have reported a mutant strain of HSV that is deficient in viral thymidine kinase-inducing activity, and recently, many kinds of mutant strains of HSV have been reported (4,5,15,29).Until recently, the study of the molecular properties of varicella-zoster virus (VZV) has been greatly hampered due to problems in the isolation offree virions with high infectivity and in the purification of viral DNA. A few results on the susceptibility and resistance of VZV to anti-herpesvirus agents have been reported (7,26,32). Yokota et al. (32) have isolated a mutant strain of VZV, which was deficient in viral thymidine kinase-inducing activity, from cells persistently infected with VZV in the presence of 5-bromo-2'-deoxyuridine. Recently, Machida et al. (18,19) University, Osaka, Japan. The YS strain was isolated in our laboratory on HEL cells from vesicular fluid of a patient with varicella (H. Kawai, T. Sakuma, K. Sasaki, M. Sato, H. Watanaloe, M. Honda, S. Ozaki, and M. Azuma, manuscript in preparation). BV-araU-resistant (BV-araUr) strains YSR, 03, 07, 018, and 026 were obtained as follows. Vero cell sheets (30-by 50-mm bottle) were infected with the stocked YS-infected cells (cell-to-cell infection) at a multiplicity of 0.1. After adsorption for 1 h at room temperature, the cell sheets were refed with maintenance medium containing 10 to 20 ,ug of IUdR or BUdR or both per ml and incubated for 24 h at 37°C. The cell sheets were washed with phosphate-buffered saline solution (pH 7.4), replenished with fresh maintenance medium, and incubated for 48 h at 370C. Then, 0.1 to 1 jig of BV-araU (200 to 2,000 times the MIC for parent YS strain) per ml was added and cultivated until a cytopathogenic effect (CPE) was apparent. One or a few small plaque-like CPE was observed on the Vero cell sheets about 7 days after infection, and after an additional 2 or 3 days, the CPE was dominant. The virus-in...

Inhibition of varicella-zoster virus-induced DNA polymerase by a new guanosine analog, 9-[4-hydroxy-2-(hydroxymethyl)butyl]guanine triphosphate

“…Several of these triphosphates act selectively on the DNA polymerase level. Many HSV-1 and VZV strains that are resistant to various nucleoside analogs have been described (4,5,7,9,21,24,(26)(27)(28). We and others have previously shown that VZV strains with deficient TK activities have a decreased susceptibility to acyclic guanosine analogs like ACV and 2HM- Cytomegalovirus, which lacks a virus-induced TK, is not susceptible to these compounds but is susceptible to other modified nucleosides that can be phosphorylated by cellular enzymes (15).…”

Efficacies of antiherpesvirus nucleosides against two strains of herpes simplex virus type 1 in Vero and human embryo lung fibroblast cells

“…In the many reports about resistant mutants to antiherpesvirus drugs, almost all had mutations for the induction of or for the affinity to TK or DNA polymerase (5,6,10,17,25). In this study, we have revealed that in addition to the difference in viral TK activities, the size of the thymidine and thymidine phosphate pools and TS activity in HSVinfected cells are also important to the susceptibility of HSV to antiherpesvirus drugs.…”

Drug Susceptibilities of Isolates of Varicella‐Zoster Virus in a Clinical Study of Oral Brovavir

“…In this study, however, drug-resistant mutations of VZV were not detected at this time during the interval studied. In addition, the drug susceptibility was observed to be generally comparable for isolates obtained before and during brovavir therapy, and VZV has been shown to be relatively unlikely to become drug-resistant through mutation (10). Viral mutation is unlikely to occur at least during such a short period of brovavir treatment for zoster conducted in the present clinical study, although idoxuridine and acyclovir have been found to induce drug-resistant mutants in the treatment of herpes simplex (2, 9).…”