In order to obtain polyclonal antibodies against the fibrillar(Fiber)protein of fowl ade-novirus serotype 11(FAdV-11)and investigate its cross-reactivity to different serotypes of FAdV Fiber,the gene encoding the FAdV-11 Fiber protein was cloned into a prokaryotic expression vec-tor pET-32a by homologous recombination technology,then the plasmid was transformed into BL21(DE3)receptor cells,and the purified recombinant protein was used as an immunogen to im-munize rabbits to prepare polyclonal antibody after induced expression,and the cross-reactivity of the polyclonal antibody against different serotypes of FAdV Fiber proteins was identified by West-ern blot and indirect immunofluorescence(IFA).The results showed that the His-FAdV-11-Fiber recombinant protein was mainly expressed as inclusion bodies and was well expressed.Western blot and IFA showed that the prepared polyclonal antibody reacted with the Fiber proteins of FAdV-8a,FAdV-8b,and FAdV-11,but did not with the 2 Fiber of FAdV-4(Fiber 1 and Fiber 2)proteins.In conclusion,in this study,we successfully prepared rabbit polyclonal antibodies against FAdV-11 Fiber and showed that it specifically recognized the Fiber proteins of FAdV-8a,FAdV-8b and FAdV-11,which lays the foundation for further establishment of serological differential diag-nosis of FAdV-11.

In order to obtain a recombinant fusion protein of porcine β-defensin-2 and interferon αwith broad-spectrum antibacterial and antiviral activities at the same time,the genes encoding both proteins were fused in series and inserted into the pPICZαA vector.This construct was then elec-trotransferred into Pichia pastoris KM71H cells to construct an engineered strain.Following methanol-induced expression,the recombinant protein was concentrated and isolated.The cytotox-icity of the protein was assessed using the MTT assay and a porcine red blood cell hemolysis test.Subsequently,the in vitro antibacterial and antiviral activities of the recombinant fusion protein were evaluated.The results showed that the engineered strain pPICZαA-PBD2-IFNα-KM71H of Pichia pastoris was successfully obtained,and the fusion protein PBD2-IFN-α was obtained by concentrating and purifying the fermentation broth after fermentation induction and expression.Its concentration was 1.116 g/L and molecular weight was 25 kDa.When the concentration of fusion protein was lower than 4-4 g/L,it had no obvious toxicity to PK-15 cells and porcine red blood cells.The diameter of the inhibition zone produced by the fusion protein on the mixed plate of Escherichia coli and Staphylococcus aureus was(15.0±0.9)mm,which had obvious antibacterial activity.The antiviral activity of the fusion protein against VSV in PK-15 cells was 8.89 × 105 U/mL measured by Reed-Muench method.This study laid a theoretical foundation for further develo-ping the recombinant fusion protein as an antibacterial and antiviral product.

In order to obtain a recombinant fusion protein of porcine β-defensin-2 and interferon αwith broad-spectrum antibacterial and antiviral activities at the same time,the genes encoding both proteins were fused in series and inserted into the pPICZαA vector.This construct was then elec-trotransferred into Pichia pastoris KM71H cells to construct an engineered strain.Following methanol-induced expression,the recombinant protein was concentrated and isolated.The cytotox-icity of the protein was assessed using the MTT assay and a porcine red blood cell hemolysis test.Subsequently,the in vitro antibacterial and antiviral activities of the recombinant fusion protein were evaluated.The results showed that the engineered strain pPICZαA-PBD2-IFNα-KM71H of Pichia pastoris was successfully obtained,and the fusion protein PBD2-IFN-α was obtained by concentrating and purifying the fermentation broth after fermentation induction and expression.Its concentration was 1.116 g/L and molecular weight was 25 kDa.When the concentration of fusion protein was lower than 4-4 g/L,it had no obvious toxicity to PK-15 cells and porcine red blood cells.The diameter of the inhibition zone produced by the fusion protein on the mixed plate of Escherichia coli and Staphylococcus aureus was(15.0±0.9)mm,which had obvious antibacterial activity.The antiviral activity of the fusion protein against VSV in PK-15 cells was 8.89 × 105 U/mL measured by Reed-Muench method.This study laid a theoretical foundation for further develo-ping the recombinant fusion protein as an antibacterial and antiviral product.