Inhibition of hepatitis B virus replication by pokeweed antiviral protein in vitro

AIM: To explore the inhibitory effects of pokeweed antiviral protein seed (PAP-S) and PAP encoded by a eukaryotic expression plasmid on hepatitis B virus (HBV) replication in vitro. METHODS: HepG2 2.2.15 cells in cultured medium were treated with different concentrations of PAP-S. HBsAg, HBeAg and HBV DNA in supernatants were determined by ELISA and fluorescent quantitative PCR respectively. MTT method was used to assay for cytotoxicity. HepG2 were cotransfected with various amounts of PAP encoded by a eukaryotic expression plasmid and replication competent wild-type HBV 1.3 fold over- length plasmid. On d 3 after transfection, HBsAg and HBeAg were determined by using ELISA. Levels of HBV core-associated DNA and RNA were detected by using Southern and Northern blot, respectively. RESULTS: The inhibitory effects of PAP-S on HBsAg, HBeAg and HBV DNA were gradually enhanced with the increase of PAP concentration. When the concentration of PAP-S was 10 μg/mL, the inhibition rates of HBsAg, HBeAg and HBV DNA were 20.9%, 30.2% and 50%, respectively. After transfection of 1.0 μg and 2.0 μg plasmid pXF3H-PAP, the levels of HBV nucleocapside- associated DNA were reduced by 38.0% and 74.0% respectively, the levels of HBsAg in the media by 76.8% and 99.7% respectively, and the levels of HBeAg by 72.7% and 99.3% respectively as compared with controls. Transfection with 2 μg plasmid pXF3H-PAP reduced the levels of HBV nucleocapside-associated RNA by 69.0%.CONCLUSION: Both PAP-S and PAP encoded by a eukaryotic expression plasmid could effectively inhibit HBV replication and antigen expression in vitro, and the inhibitory effects were dose-dependent.

Development of Novel Therapeutics for Chronic Hepatitis B

Chronic infection of hepatitis B virus (HBV) presents one of the serious public health challenges worldwide. Current treatment of chronic hepatitis B (CHB) is limited, and is composed of interferon and nucleoside/nucleotide reverse transcriptase inhibitors (NRTI). Interferon is poorly tolerated and is only responsive in a small fraction of CHB patients and NRTIs often face the problem of emergence of drug resistance during long-term treatment. The current treatment of CHB can be improved in several ways including genotyping mutations associated with drug resistance before treatment to guide the choice of NRTIs and suitable combinations among NRTIs and interferon. It is important to continue research in the identification of novel therapeutic targets in the life cycle of HBV or in the host immune system to stimulate the development of new antiviral agents and immunotherapies. Several antiviral agents targeting HBV entry, cccDNA, capsid formation, viral morphogenesis and virion secretion, as well as two therapeutic vaccines are currently being evaluated in preclinical studies or in clinical trials to assess their anti-HBV efficacy.

Effect of Eliminated the Breeding Pigs with Unqualified CSFV Antibody on Sows' Reproductive Performance and Pigs' Growth Performance

[Objective] The aim was to explore the effect of eliminated the breeding pigs with unqualified CSFV antibody on sow's reproductive performance and pig's growth performance so as to provide a scientific basis for the eliminating of the breeding pigs with unqualified CSFV antibody in large-scale pig farms.[Method] Serum samples from three scale pig farms were collected and tested with HerdChek CSFV-ELISA kit,then provided a certain scientific basis for scale pig farm to eliminate the unqualified(antibody blocking rate<50%)breeders after booster immunization.[Result ] After eliminating the breeding pigs with unqualified CSFV antibody,the average litter number of piglet in three pig farms(A,B,C)were increased by 0.29(P<0.05),0.40(P<0.01),0.39(P<0.01)respectively;the average number of survival piglets were increased by 0.54(P<0.01),0.35(P<0.01),0.62(P<0.01)respectively;the average litter number of weaned piglets were increased by 0.65(P<0.01),0.71(P<0.01),0.81(P<0.01)respectively.The difference in weight gain of piglet at 30-60 d of age was extremely significant(P<0.01),but inconspicuousness for the swine pregnancy rate,the survival rate of weaned piglet and piglet at 30-60 d of age.[Conclusion] The eliminating the breeding pigs with unqualified CSFV antibody can significantly improve the performance of breeder and piglets.