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@#Objective To express glycoprotein H(gH)of pseudorabies virus(PRV)in mammalian cells and detect its immunogenicity.Methods The gH gene fragment of PRV-XiangA strain was amplified by PCR and inserted into mammalian cell expression vector pIRES-neo3 to construct recombinant expression plasmid pIRES-gH,which was transfected to HEK-293F cells and cultured in suspension for 5 d. The cell culture supernatant was identified by Western blot and purified by nickel ion chromatography column. The purified gH was emulsified with ISA 201 VG adjuvant to immunize 8 female ICR mice,and 8 mice in control group were immunized with the same amount of adjuvant,which was strengthened at 5 and 8weeks after the first dose respectively. The blood samples were collected at 4,7 and 10 weeks after the first dose and detected for the titer of specific antibody and neutralizing antibody in serum of mice;The mice were challenged with PRVXiangA strain(1. 5 × 104TCID50)by nasal drops 2 d after the third blood collection,and observed for the morbidity and mortality daily.Results The recombinant expression plasmid pIRES-gH was constructed correctly as identified by sequencing. The gH protein was successfully expressed and modified by glycosylation in mammalian cells with good reactivity,and about 625 μg purified protein was obtained under 100 mL culture volume. After three times of immunization,mice produced high level of specific antibody and showed the effect of neutralizing PRV,and the titer of neutralizing antibody reached 1∶256. In the challenge test,all the mice in control group became ill and died,while half of the mice in gH immunized group did not get sick with a survival rate of 50%.Conclusion PRV gH was successfully expressed in mammalian cells,and its immune protection was confirmed for the first time,which provided experimental basis for the further research and application of gH,and also provided a new idea for the development of PRV subunit vaccine.
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@#Objective To express recombinant human interferon λ1(rhIFNλ1)by transient transfection in HEK-293F cells and identify it. Methods Two signal peptides[T cell receptor(TCR)and nature signal peptide(NSP)],three vectors[pcDNA3.4,ubiquitous chromatin opening element(UCOE)and PFR]and the target gene rhIFNλ1 were used to construct recombinant plasmids of six signal peptide-vector combinations. Using HEK-293F as host cells,the recombinant plasmids were transfected transiently to express rhIFNλ1 on a shake flask scale. The recombinant plasmid UCOE-Q46-λ with low glycosylation rhIFNλ1 was constructed by using NSP and vector UCOE,and transfected transiently into HEK-293F cells. The expressed product was purified by cation exchange chromatography(HiTrap SP FF),blue gel chromatography(HiTrap Blue HP)and gel filtration chromatography(Sephacryl S-100 HR),which was then analyzed by Western blot and reversed-phase HPLC,and determined for its molecular mass and N-terminal amino acid sequence by mass spectrometry. Results Six recombinant plasmids were constructed correctly as identified by double enzyme digestion and sequencing. With the extension of transfection time,the expression levels of the six expressed products increased gradually,and reached the highest level of10 ～ 20 mg/L at the 6th day of transfection. Double enzyme digestion and sequencing identification proved that the recombinant plasmid UCOE-Q46-λ with low glycosylation rhIFNλ1 was constructed correctly. The recombinant plasmid UCOE-Q46-λwas transfected into HEK-293F cells for 6 d. The purified product of cell culture supernatant showed a relative molecular mass of about 27 800 and a purity of 97. 372%,which showed specific binding to mouse anti-human IL-29/IFNλ1 monoclonal antibody;Two peaks were detected by reversed-phase HPLC,and the peak was showed at 15. 6 min and 20. 0 min respectively;The mass spectrometry molecular mass was about 24 000;The N-terminal five amino acids were G-P-V-P-T.Conclusion The rhIFNλ1 expressed by HEK-293F cells has high purity,which lays a foundation of further study of the protein.