The topoisomerase I inhibitor, camptothecin, inhibits equine infectious anemia virus replication in chronically infected CF2Th cells.
Camptothecin (CPT), a topoisomerase I-specific inhibitor, was found in this study to inhibit the replication of equine infectious anemia virus (EIAV) in chronically infected CF2Th cells (designated CF2Th/EIAV). By measuring viral reverse transcriptase activity in the culture medium, we demonstrated that treatment for 1 h with noncytotoxic doses of this drug inhibited production by 32 to 52%, whereas continuous exposure to this drug resulted in an 85 to 92% inhibition. No effect on the viability or growth rate of the cells was detected in any of these treatments. Indirect immunofluorescence analysis of the CPT-treated CF2Th/EIAV cells with anti-p26 capsid protein antibodies showed 60 to 85% reduction in the immunofluorescence-positive cells following drug treatment, and radioimmunoprecipitation analysis of these cells showed a comparable decrease of the pr55gag precursor protein. These data suggest that CPT acts as an anti-EIAV agent to block virus replication in the chronically infected cells.
Priel
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Laboratory of Molecular Oncology, National Cancer Institute Frederick Cancer Research and Development Center, Maryland.
Showalter
S D
SD
Roberts
M
M
Oroszlan
S
S
Blair
D G
DG
D000818:Animals; D000956:Antigens, Viral / Q000096:biosynthesis; D002166:Camptothecin / Q000494:pharmacology*; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D005455:Fluorescent Antibody Technique; D004860:Infectious Anemia Virus, Equine / Q000187:drug effects* / Q000201:enzymology / Q000276:immunology / Q000502:physiology; D015531:Radioimmunoprecipitation Assay; D059004:Topoisomerase I Inhibitors; D014779:Virus Replication / Q000187:drug effects*
D000956:Antigens, Viral; D059004:Topoisomerase I Inhibitors; D002166:Camptothecin