OBJECTIVETo establish a high efficient human coagulation factor VIII (FVIII) eukaryotic stable expression system using lentiviral vector, and determine its biosafety.

METHODSLentiviral transfer plasmid carrying human B-domain-deleted FVIII(BDDhFVIII)-IRES-GFP(BDDhFVIII/pXZ9)or IRES-GFP(pXZ9) was constructed. Lentivirus particles were produced by transiently co-transfected 3-plasmids into 293FT cells and further concentrated via ultracentrifugation. CHO cells were infected, 72h later, the FVIII antigen (FVIII:Ag) concentration in the medium was examined by ELISA, the activity was detected via one stage coagulation,and the transcription of FVIII in the infected CHO cells was determined by RT-PCR.Virus infection ability in the medium and the gag gene in CHO cells were determined to evaluate the model's biosafety.

RESULTSLentiviral transfer plasmid BDDhFVIII-IRES-GFP(BDDhFVIII/pXZ9)carrying human B-domain-deleted FVIII or IRES-GFP (pXZ9) was successfully constructed, and high titer lentiviruses has been prepared. The lentivirus could infect CHO cells efficiently, after an additional 72 h, the FVIII:Ag concentration had up to (1724.9±283.7) mU/ml, the FVIII:C level increased to (10.58±1.55)%, and transcripts of BDDhFVIII mRNA could be measured by RT-PCR. Neither the gag gene nor the virus in the supernatant was detected.

CONCLUSIONLentivirus-mediated human coagulation factor VIII could be expressed efficiently in CHO cells. The system couldn't produce offspring virus, proving a good biosafety.