重组腺病毒rAd-H5HA-EGFP对小鼠免疫保护性的研究

Protective efficacy of a recombinant adenovirus rAd-H5HA-EGFP in mice

将重组腺病毒rAd-H5HA-EGFP以不同免疫剂量接种BALB/c小鼠,通过检测小鼠免疫后的抗体以及抵抗H5N1亚型流感病毒攻击的保护对rAd-H5HA-EGFP的免疫保护性进行了评估。分别以108 TCID50、107 TCID50的rAd5-H5HA-EGFP免疫小鼠,初次免疫后3周进行加强,剂量为2×108 TCID50和2×107 TCID50,同时以接种rAd5-EGFP和PBS的小鼠作为对照。二免后3周,将各组试验小鼠随机分为2组,分别应用106 EID50的SW/FJ/1/01株和CK/HuN/77/05两株H5N1亚型流感病毒进行攻击。结果显示,重组病毒108 TCID50和107 TCID50的免疫剂量均能够诱导高水平的HI抗体生成,rAd-H5HA-EGFP免疫小鼠在受到病毒SW/FJ/1/01和CK/HuN/77/05攻击后,与接种腺病毒rAd-EGFP和PBS的对照组小鼠相比,没有出现明显的体质量减轻,攻毒后病毒在免疫小鼠体内的复制被完全或部分抑制,脏器内检测到的病毒含量明显低于对照组小鼠;免疫小鼠在受到CK/HuN/77/05毒株攻击时,没有出现死亡(0/5),而接种rAd-EGFP和PBS的对照组小鼠均有死亡,死亡比例分别为4/5和5/5。以上结果表明,该重组rAd-H5HA-EGFP对小鼠具有良好的免疫保护性,有望成为1株新型H5N1亚型动物流感疫苗的候选重组毒株。

Protective efficacy of a recombinant adenovirus rAd-H5HA-EGFP was evaluated by detecting HI antibody titer and protection from H5N1 subtype influenza virus induced by different dose of rAd-H5HA-EGFP in BALB/c mice.Mice were primarily immunized with 108 TCID50 and 107 TCID50 of rAd-H5HA-EGFP,respectively,then boosted with 2×108 TCID50 and 2×107 TCID50 of rAd-H5HA-EGFP,respectively,three weeks later.The mice inoculated with rAd-EGFP and PBS were used as control groups for challenge experiment.Three weeks after the booster immunization,each group of mice were challenged with 106 EID50 of SW/FJ/1/01 and CK/HuN/77/05,respectively.High titers of HI antibodies were detected after vaccination with 108 TCID50 and 107 TCID50 of rAd-H5HA-EGFP.Compared to the sharply weight loss in the control mice inoculted with rAd-EGFP and PBS,weight loss was not observed in the mice vaccinated with rAd-H5HA-EGFP.The replication of challenge viruses in the immunized mice was inhibited completely or partially,and the virus titers titrated was significantly decreased in the vaccinated mice.The mice inoculated with rAd-H5HA-EGFP were all survived after challenge with SW/FJ/1/01 and CK/HuN/77/05,while 4 were dead in rAd-EGFP inoculated mice and 5 in PBS inoculated mice after challenge with CK/HuN/77/05,respectively.These results demonstrated that rAd-H5HA-EGFP would be an ideal vaccine candidate for H5N1 subtype animal influenza in the future.