Objective IFN-? is a pleiotropic cytokine with potent immunomodulatory effects and antiviral activity. To study the mechanism of IFN-? clearing duck hepatitis B virus (DHBV) in ducks, it is essential to establish a method to quantify expression of DuIFN-? in immune response. In the present study,a semi-quantitative competitive RT-PCR was developed to quantify expression of duck IFN-?(DuIFN-?) mRNA by PBMCs. Methods Based on ?-actin consensus sequence, fishing the ?-actin gene as house keeping gene from duck PBMC by RT-PCR. A competitive internal control was constructed and the competitive RT-PCR system could be used to quantify the transcription of DuIFN-? mRNA. Results After duck PBMCs were stimulated in vitro with PHA, the peak of DuIFN-? expression was at 24-36h. Then RT-PCR method was applied to detect DuIFN-? mRNA transcription by PBMCs from DHBV infected ducks immunized with DuIFN-? plasmid plus DNA vaccine or DNA vaccine alone. Results showed that expression of DuIFN-? in ducks co-immunized with DuIFN-? plasmid were higher than other groups immunized without DuIFN-? plasmid as adjuvant. Conclusions The results indicated that DuIFN-? gene could be a useful adjuvant to develop vaccines. The semi-quantitation of DuIFN-? mRNA by competitive RT-PCR provides the basis for future study of the mechanism of IFN-? in duck hepatitis B virus persistent infection.

Objective To identify the role of RNA-editing enzyme ADAR1 (adenosine deaminase acting on RNA) in EV71 infection and virus mutation.Methods RNAi technology was applied to establish ADAR1 knock-down stable cell lines.Then the cells were served to evaluate the role of ADAR1 in EV71 infection by MTT assay for detecting virus-induced cell viability,virus plaque assay for quantification of the virus titer and the cellular susceptibility to the virus,and Western blot for virus protein expressions.ADAR1-mediated RNA editing can result in the genetic A-G and T-C mutations.To further determine whether the effects of ADAR1 on EV71 infection were correlated with ADAR1-mediated EV71 RNA editing and therefore increased the viral mutations during the infection,the characteristics of EV71 mutation were analyzed based on the different full-length viral genomes from epidemic regions.The viral genome was also sequenced from the infected ADAR1 knock-down cells.Results After ADAR1 knock-down,the cell viability decreased quickly after the virus infection,and formed much more and larger sizes of plaques than the control cells.The virus capsid protein VP1 expressions and virus titer in the cells culture media were both increased in ADAR1 knockdown cells.Statistic analysis showed that A-G and T-C mutations were the major mutations of EV71,which were believed to be the hot sites for RNA-editing.However,the results of viral RNA genomic sequencing data indicated that ADAR1 did not edit EV71 genome directly.Conclusions ADAR1 was a restriction factor for controlling EV71.However,ADAR1 does not directly edit EV71 genome.