基于假病毒的人乳头瘤病毒小鼠感染模型的建立及HPV16VLP疫苗保护性评价

Establishment of human papillomavirus pseudovirion infection model in mouse for potency evaluation of HPV16 VLP Vaccine

目的建立基于假病毒的人乳头瘤病毒(human papillomavirus,HPV)小鼠感染模型并应用于HPV16 VLP疫苗的保护性评价。方法利用293FT细胞制备携带Luc报告基因的HPV16假病毒,纯化后检测HPV16假病毒滴度和性质;利用醋酸甲羟孕酮和β-雌二醇处理雌性BAL B/c小鼠,然后用壬苯醇醚-9(N-9)化学损伤BALB/c小鼠阴道,6 h后用HPV16假病毒感染小鼠阴道,48 h后使用活体检测仪检测小鼠阴道中Luc报告基因的表达情况;最后,利用该感染模型评价HPV16 VLP疫苗的保护能力。结果获得了含有Luc报告基因的HPV16假病毒,建立了HPV假病毒纯化方法;Western blot结果显示HPV16假病毒中含有L1和L2蛋白;建立了HPV假病毒感染小鼠模型,并通过不同剂量的假病毒感染实验表明,该感染模型所需的最低假病毒剂量是1.7×104TRLU;利用该模型获知HPV16 VLP疫苗具有较强的抵抗HPV16假病毒感染的能力,当中和抗体滴度为256时即可阻碍HPV假病毒感染。结论本研究成功地建立了HPV假病毒小鼠感染模型,并运用该模型评价了HPV16 VLP疫苗的保护作用,为HPV中和抗体研究和候选疫苗的免疫保护评价提供了有效工具。

Objective To establish a mouse model of genital human papillomavirus（ HPV） pseudovirion（ Ps V） transmission and evaluate the protective potency of HPV16 VLP vaccine. Methods HPV16 Ps V with the encapsidated luciferase expressing plasmid Luc were generated from 293 FT cells and purified by size-exclusion chromatography. The endpoint titers of HPV16 Ps V-Luc were determined on 293 FT cells,denoted as TRLU / m L. For in vivo genital challenge,mice were synchronized in a diestrus-like status by a subcutaneous injection with 0. 1 μg β-estradiol and then with 3mg Depo Provera after 24 hours. Six hours prior to HPV16 Ps V-Luc challenge,deeply anesthetized mice were intravaginally pretreated with 50 μL of 4%nonoxynol-9（ N-9）. HPV16 Ps V-Luc was thoroughly mixed with 20 μL solution containing 4% carboxymethylcellulose（ CMC） and intravaginally instilled using a positive-displacement pipette. Forty-eight hours after Ps V-Luc challenge,mice were anesthetized and D luciferin was intravaginally instilled. After 3 minites,bioluminescence was measured with a cryogenically cooled Xenogen IVIS camera system. Then,the murine genital challenge model was used to determine the potency that HPV16 VLP vaccine is efficient at preventing HPV infection. Results HPV16 Ps V-Luc was generated and purified from 293 FT cells. HPV16 Ps V-Luc was verified to containe L1 and L2 protein by Western blot. HPV 16 Ps V-Luc successfully infected vaginal epithelial cells of mouse and the murine genital challenge model was established. To achieve consistent bioluminescence,the minimal dose of HPV16 Ps V-Luc was 1. 7 × 104 TRLU. The protective potency of HPV16 VLP vaccine was shown using this murine model. Our data showed that immune serum with over neutralizing antibody titer of 256-fold was sufficient to confer protection against HPV Ps V genital infection. Conclusion The murine genital challenge model of HPV16 was successfully established,and the model is used to evaluate the potency of HPV16 VLP vaccine against in vivo genital HPV16 Ps V challenge. Our model will benefit for the investigation of HPV neutralization and the potency evaluation of the HPV vaccine.