【摘要】 目的　观察乙型肝炎病毒S基因表达质粒 (PS)诱导小鼠体液免疫及对HBV转基因(Tg)小鼠血清HBsAg的影响。方法　将S基因插入到pcDNA3 1+的BamH1位点上构建了PS。体外证实PS表达HBsAg。再分别免疫BALB/C小鼠和Tg小鼠各 10只。另用pcDNA3 1+免疫 4只BALB/C小鼠。每只小鼠每次肌肉注射纯化质粒 10 0 μg ,共 3次。用ELISA检测每份血清抗 HBs的效价。结果　PS免疫BALB/C小鼠 ,2～ 4周时出现抗 HBs,第 8周时平均为 135IU/L。该PS免疫Tg鼠多在 6～ 8周时出现抗体 ,平均 39IU/L。其中 4只HBsAg阳性的Tg鼠免疫后HBsAg转阴。结论　PS不仅能够有效地诱导BALB/C和Tg小鼠的体液免疫 ,还能抑制Tg鼠HBsAg的产生更多还原

【Abstract】 Objective To study the DNA immunization of a plasmid expressing HBsAg in BALB/C mice and HBVtransgenic (Tg) mice Methods The S gene obtained by polymerase chain reaction was ligated with pGEMTeasy vector and then subcloned into pcDNA 31+ to construct a new plasmid (PS), whose fidelity was verified through sequencing The ability to express HBsAg was demonstrated by transfection of PS into P815 cells The PS was then used to immunize 10 BALB/C mice and 10 Tg mice by way of injection 4 mice were immunized with pcDNA31+ Each mouse was injected intramuscularly with one of those plasmids in the same total dose of 300 μg divided into 3 times Another 6 BALB/ C mice were injected with HBsAg protein as control All mice were bled before the immunization and biweekly thereafter Sera of the mice were detected for antiHBs with ELISA Results 8 of the 10 mice immunized with PS had detectable antiHBs The average level of antiHBs is 135 IU/L While in the Tg mice, antiHBs occurred during 6 to 8 weeks after injection The average level is 39 IU/L HBsAg became negative in all the 4 mice with sera positive for HBsAg before immunization Conclusion PS is effective to elicit a positive humoral immune response in BALB/C mice PS can also stimulate an immune response in Tg mice, which seems to be responsible for the disappearance of HBsAg更多还原