基于PCR的乙型肝炎病毒体外中和试验

A new PCR-based in vitro neutralization assay of hepatitis B virus

目的 建立一种新的基于PCR的乙型肝炎病毒(HBV)体外中和试验,将其用于HBV中和抗体的检测,为新型HBV疫苗的评估提供一种体外模型。方法 待检免疫血清与已知HBV作用后接种HepG2 细胞,吸附、洗涤、培养后提取细胞核酸,PCR检测HBVDNA以判断中和试验结果。结果 免疫血清与10倍最小PCR感染剂量的HBV作用后接种细胞,培养2 4h后检测表明,其中和滴度高,结果稳定。市售疫苗免疫小鼠血清、多数抗HBsELISA阳性人血清和2份含HBVS区的新型候选疫苗的免疫血清中和试验阳性,而正常小鼠血清、戊型肝炎病毒重组蛋白免疫血清和抗 HBs阴性人血清中和试验阴性。结论 基于PCR的HBV体外中和试验简单、快速、经济,具有良好的特异性和敏感性,可以用于新型HBV疫苗免疫效果的评估。

Objective To establish a PCR-based neutralization assay of hepatitis B virus (HBV), which may be applied for detecting neutralizing antibodies against HBV and used as an in vitro model to screen new HBV vaccines. Methods Immune serum was mixed with HBV stock. The mixture was incubated and then inoculated onto Hep G 2 cell monolayers. After adsorption, washing and incubation, HBV DNA was extracted from the cells and detected by PCR. The neutralization effect was determined based on the PCR results. Results Two HBV stocks suitable for the neutralization assay were selected from 18 serum samples collected from patients with hepatitis B. The neutralization assay was optimized in the conditions of using 10 infectious doses of the HBV stock and incubating the cell culture for 24 hours prior to PCR detection. Four immune sera obtained from mice immunized with commercial HBV vaccine and 2 serum specimens from mice immunized with 2 new HBV vaccine candidates definitely blocked the in vitro HBV adsorption. However, 4 sera obtained from normal mice and 2 sera from mice immunized with 2 hepatitis E virus vaccine candidates did not show any neutralizing activity. Conclusion The established new PCR-based in vitro HBV neutralization assay is a simple, rapid and economic assay. It may be used as a model for primary evaluation for HBV vaccine candidates prior to primate assay.