Aims:To evaluate the anti-hepatitis B virus (anti-HBV) effects and mechanisms of recombinant human serum albumin-interferon-α-2b fusion protein (rHSA-IFNα-2b) in vitro and in vivo. Methods: The inhibiting effects on HBV replication were examined in the HepG2 2.2.15 cell line and in ducks, and the expressions of signal transducers and transactivator 1 (STAT1), IFN-stimulated gene factor 3 (ISGF3) and 2′,5′-oligoadenylate synthetase 1 (OAS1) were investigated by the reverse transcription-polymerase chain reaction (RT-PCR) and Western blot analysis. Results: In vitro,at concentrations from 0.075 to 1.2 nmol/l, rHSA-IFNα-2b inhibited the releases of extracellular hepatitis B surface antigen, hepatitis B e antigen and HBV DNA in a dose-dependent manner; rHSA- IFNα-2b also increased the levels of STAT1, ISGF3 and OAS1. In vivo, rHSA-IFNα-2b reduced the levels of alanine aminotransferase, aspartate aminotransferase, total bilirubin and duck hepatitis B virus (DHBV) DNA in the sera of DHBV-infected ducks. Conclusions:We provide the first evidence that rHSA-IFNα-2b significantly inhibits HBV replication in HepG2 2.2.15 cells and in ducks, and that the antiviral effect of rHSA-IFNα-2b in vivo is more potent than that of IFNα-2b. The anti-HBV mechanism probably operates by triggering the JAK-STAT signaling pathway and increasing the expression of OAS1.

The fully synthetic humanized phage antibody library has the advantages including the minimized immunogenicity, which frequently happened in hybridoma cell-based antibody production. In this paper, using the constructed diverse complementarity determining region gene library and the germline gene as the backbone, we constructed eight single-chain antibody libraries and a combinatorial antibody library with a big capacity of 1.41 × 1010. M13EEA helper phage that was engineered from M13KO7 was applied to prepare phage antibody library. The eukaryotic expression of T-cell immune receptor with Ig and ITIM domain (TIGIT) antigen was used as a target antigen for screening. The screening of antigen-specific single-chain Fc-fused protein was performed through evaluation of binding affinity based on ELISA analysis. The IgG antibody was prepared with the screened single-chain protein. Finally, the CB3 antibody was screened out which exhibits the highest binding affinity with TIGIT with the Kd value of 8.155 × 10−10 M.