Effects of adenine arabinoside on lymphocytes infected with Epstein-Barr virus

Abstract

Low concentrations of adenine arabinoside inhibited growth of two Epstein-Barr virus producer cell lines in culture, while not significantly affecting a nonproducer cell line and a B-cell-negative line. These observations were extended to include freshly infected cells. Mitogen-stimulated human umbilical cord blood lymphocytes were unaffected by the drug at concentration levels that inhibited [3H]thymidine incorporation into the DNA of Epstein-Barr virus-stimulated cells. DNA synthesis in Epstein-Barr virus-superinfected Raji cells was also adversely affected by adenine arabinoside. However, these same low concentrations of adenine arabinoside in the triphosphate form produced less effect on DNA synthesis in nuclear systems and DNA polymerase assays than on growth or DNA synthesis in whole cells. Therefore the effects reported here of low concentrations of the drug on whole cells may be only in part related to DNA polymerase inhibition. The work reported here suggests that adenine arabinoside has multiple sites of action in infected cells. The synthesis of 9-fp-D-arabinofuranosyladenine (adenine arabinoside, or ara-A) as a potential anticancer agent was first reported in 1960 (18). Since then ara-A has been reported to have antitumor and antiviral effects for tissue culture cells and laboratory animals and in clinical use in treatment of certain virally caused diseases. Reports between 1964 and 1968 have shown that ara-A has specific antiviral effects in tissue culture for herpes, pox, and Rous sarcoma viruses (11, 29, 32; R. W. Sidwell, G. Arnett, and G. J. Dixon, Program Abstr. Intersci. Conf. Antimicrob. Agents Chemother., 7th, Chicago, Ill., Abstr. no. 64, 1967). Furthermore, inhibition of mammalian ribonucleotide reductase and DNA polymerase by ara-A were demonstrated (12, 22). Certain studies have shown that mammalian a polymerases are sensitive to ara-A (23-25;

Sedimentation characteristics of newly synthesized Epstein-Barr viral DNA in superinfected cells

“…Concentrations of 20 and 100 ng/ml (sufficient to inhibit replication of covalently closed supercoiled plasmids [6,11,17]) inhibited EBV DNA synthesis at the 10 to 17% level. It has previously been shown that inhibition of EBV DNA synthesis leads to a decline in VCA production (4,5,7,14,18). The percentage of cells in the P3HR-1 producer cell line expressing VCA declined with increasing concentration of ethidium bromide proportionately to the observed inhibition of DNA synthesis; i.e., 500 ng of ethidium bromide per ml yielded a 50% inhibition of both DNA and VCA production.…”

“…x 10' cells/ml. The infection was allowed to proceed at 350C for an additional 4 h, after which the cells were pelleted, washed twice in phosphate-free minimal essential medium, and then suspended in phosphatefree minimal essential medium containing 1% heatinactivated (dialyzed) fetal calf serum to a concentration of 5 x 105 to 1 x 106 cells/ml. At this time [methyl-3H]thymidine (Schwarz/Mann; 18 Ci/mmol) was added as indicated (see figure legends).…”

Immunofluorescence Microscopy and Flow Cytometry Characterization of Chemical Induction of Latent Epstein-Barr Virus

“…The cells were maintained in RPMI 1640 medium containing 10% fetal bovine serum with 100 U of penicillin per ml, 100 U of streptomycin per ml, 2.5 g of amphotericin B per ml, and 2 mM glutamine at 37°C in a humidified atmosphere with 5% CO 2 . Raji and B95-8 cells show a lag in growth for approximately 24 h after splitting, followed by exponential growth peaking at 5 days and, finally, a subsequent decrease in the cell count (4,5). For these studies two subpopulations of Raji and X50-7 cells were maintained in 25-cm 2 flasks for at least 2 weeks prior to chemical induction: cultures designated fast growing were split 1:1 with fresh medium twice per week (1st and 4th days), and cultures designated slow growing were split 1:1 with fresh medium once per week.…”

Inhibition of Epstein-Barr Virus Replication by a Benzimidazole l -Riboside: Novel Antiviral Mechanism of 5,6-Dichloro-2-(Isopropylamino)-1-β- l -Ribofuranosyl-1H-Benzimidazole

“…Compounds that inhibit replication of EBV in vitro include adenine arabinoside (3,11), phosphonoformic acid, and phosphonoacetate (16,60,63,77), a class of halogenated nucleoside analogs exemplified by FIAC [1-(2-fluoro-2-deoxy-␤-D-arabinofuranosyl)-5-iodocytosine] (42,46), BVDU [E-5-(2-bromovinyl)-2Ј-deoxyuridine) (43,44), ganciclovir (39), acyclovir (ACV) (12,24,45), and the phosphonated nucleoside analogs HPMPC {(S)-1-[(3-hydroxy-2-phosphonylmethoxy)propyl]cytosine} and related compounds (40,41). Nucleoside analogs and the pyrophosphate analogs phosphonoformic acid and phosphonoacetate inhibit replication of most or all of the herpesviruses.…”