Antiviral effects of two antisense phosphorothioate oligodeoxynucleotides against Japanese encephalitis virus strain SA--14 in cultured BHK21 cells

摘要

To investigate the potential utility of nuclease--resistant oligodeoxynucleotides (S-ODN) as anew class of antiviral agents. Methods: Two antisense phosphorothioate analogues (20--iner) complementary to thesequences of the first AUG codon and 5’ terminus of NSS of JEV SA--14 genome have been synthesized and their effects on CPE, viral antigen expression and virus plaque formation were tested in vitro. Results: The resultsshowed that 1. 0 pmol/L of S-ODN greatly deferred the onset of CPE in cultured BHKZI cells for at least 48 h.Addition of 5. 0 pmol/L or more S--ODN to culture medium fluid, 2 h prior to 100TCID,,virus inoculum, notablysuppressed viral antigen expression in the cells by making it lower than the limit of EIA detection in 48 h. The inhibition lasted more than 96 h. Viral plaque assay results demonstrated that S-ODN were most effect’ive within 18h with plaque inhibition rate over 90% by 5. 0 pmol/L S--ODNI. The inhibitory activity soon faded in 24 h. In addition, high concentrations (up to 80. 0 pmol/L) of S--ODN did not show any obvious cytotoxicity in 6 d by usingtrypan blue dye exclusion method. Conclusion: The specific synthetic S--ODN transitorily inhibited JEV replicationin BHK--ZI cells with characteristics of specificity and S--ODN dose--dependence.