Expression of t antigen fusion protein of JC virus and preparation of its polyclonal antibody / 中华传染病杂志

Objective To construct prokaryotic expression vector carrying jc virus(JCV)t-antigen gene,express and purify this fusion protein.Methods The JCV t-antigen gene from a cerebrospinal fluid sample was amplified using polymerase chain reaction(PCR)method.After sequencing.the gene was cloned into plasmid pET32a(+)to construct recombinant prokaryotic expression vector pET32a(+)-t.The t-antigen fusion protein was expressed by isopropy-~D-thiogalactoside(IPTG)induction and prepared in large scale,then purified by Ni+affinity column chromatography.The polyclonal antibody was obtained from the BAI.B/C mouse immunity by the purified protein.Results The relative molecular nlass of recombinant protein expressed by pET32a(+)-t was about 41 000.Sodium dodeeylsulfate-polyaerylamide gel electrophoresis(SDS-PAGE)showed that the fusion protein W&S highly expressed after 3.5～20.Oh of IPTG induction.The antigenicity of the purified protein Was well confirmed by Western blot.The anti-mousepolyclonal antibody was obtained successfully from immunized BALB/c mice.Conclusions The prokaryotic expression vector pET32a(+)-t is successful constructed and the fusion protein is expressed and purified.Furthermore,the antibody of JCV small envelop protein t is successfully prepared.This work provides vMuable information for further study on epidemiology and biological function of t antigen.

Establishment and further identification of immortalization human hepatocyte lines / 中华传染病杂志

Objective To establish immortalized human hepatocyte lines for studies of bioartificial liver,hepatocyte transplantation,and drug metabolism in vitro.Methods Primary human hepatocytes were isolated by 4-step perfusion technique with collagenase and transfected with recombinant retrovirus containing Simian virus 40 large T antigen(SV40 LT).Subsequently,immortalized human hepatocytes were evaluated by analysis of gene expression and functional characteristics in vitro.Results Two immortalized human hepatocyte lines,HepLi2 and HepLi3,were obtained after primary human hepatocytes being infected by SV40 LT containing recombinant retrovirus for 3-4 weeks.The immortalized human hepatocytes showed classical appearance of hepatocyte observed by phase contrast microscope.The protein expression of SV40 LT in HepLi2 and HepLi3 cells were detected by Western blotting.The mRNA expressions of albumin(Alb),glutathione S-transferase(GST-p),human blood coagulation factor X(HBCF-X)and β-actin in HepLi2 and HepLi3 cells were detected by reverse transcription polymerase chain reaction(RT-PCR),and the mRNA expressions of cytochrome(CY)450 subtypes(CYP3A5,CYP2E1,CYP2C8-19 and CYP3A4)in HepLi2 and HepLi3 cells were also observed by RT-PCR.Levels of alanine transaminase (ALT),lactate dehydrogenase(LDH)and Alb were detected in the supernatant of immortalized human hepatoeyte culture.Conclusions The immortalized human hepatocyte lines have the biological characteristics of primary human hepatocytes and have the CYP450 functions of hepatocytes,which may be heIDful for the studies of bioartificial liver,heoatocvte transplantation and drug metabolism in vitro.

Transfection of normal human melanocytes with SV40 T antigen gene / 中华皮肤科杂志

Objective To investigate the immortalization of human melanocytes by transfection with SV40 T antigen ( SV40T ). Methods By using SofastTM,a gene transfection reagent, the reconstructed eukaryotic expression vector SV40T-pEGFP was stably transfected into cultured primary human melanocytes, then the positive cells were selected with G418. After the positive cells were expanded in culture, the expression of SV40T gene was detected by RT-PCR and PCR, and the protein expression of SV40T by Western blotting. Results The genome DNA and total RNA were isolated from the positive cell clones, and a 288 bp fragment, which was specific for the SV40T antigen gene, was amplified. The results of immunohis-tochemistry and Western blotting confirmed the expression of SV40T protein in transfected cells. Conclusion SV40T antigen gene can successfully induce the immortalization of human melanocytes.