1月28日，国际学术杂志PLoS ONE在线发表了上海巴斯德研究所关于异源免疫策略DNA-VLP在抗高致病性禽流感H5N1病毒感染中的保护性作用的研究论文。这项研究成果由周保罗研究员领导的课题组完成。

疫苗接种是预防高致病性流感病毒H5N1大流行的有效途径，但是传统的基于鸡胚制备流感疫苗的方法在用来制备抗H5N1的疫苗时却受到严重限制，这主要是由于H5N1病毒可以杀死鸡胚。有许多新的疫苗制备形式在研究中被尝试于应对高致病性禽流感H5N1病毒，例如DNA和病毒样颗粒(VLP)类疫苗。

在本研究中，研究人员首次将DNA和病毒样颗粒(VLP)结合起来以一种异源初免-加强免疫的接种策略来应对H5N1病毒，并对该免疫策略和另外两种同源免疫策略在小鼠体内诱导出的中和抗体反应和免疫保护效果进行了比较研究。以假病毒为基础的中和抗体检测实验证实DNA-VLP在三种初免-加强免疫接种策略中所诱导出的中和抗体活性最高；而DNA-DNA所诱导出的中和抗体活性要高于VLP-VLP的。研究结果还表明，只有DNA-VLP和DNA-DNA, 而不是 VLP-VLP，能在1,000 MLD50高剂量的同源H5N1病毒攻毒实验中保护小鼠免于死亡。最后，也只有DNA-VLP能在1,000 MLD50的异源H5N1病毒攻毒实验中保护一半的小鼠免于死亡。这些结果表明在针对高致病性禽流感H5N1病毒时，异源DNA-VLP初免-加强免疫接种策略能诱导出更强的中和抗体反应和免疫保护。在未来可能的H5N1流行中，这将为临床上对异源DNA-VLP初免-加强免疫接种策略对公众健康所起的干涉保护作用进行评估提供理论支持。

该研究得到了法国卫生部研究项目、国家自然科学基金委、国家科学和技术重大专项及李嘉诚基金会等项目资助。

原文出处：

PLoS One. 2011 Jan 28;6(1):e16563.

Superior Neutralizing Antibody Response and Protection in Mice Vaccinated with Heterologous DNA Prime and Virus Like Particle Boost against HPAI H5N1 Virus.

Ding H, Tsai C, Gutiérrez RA, Zhou F, Buchy P, Deubel V, Zhou P.

Abstract

BACKGROUND: Although DNA plasmid and virus-like particle (VLP) vaccines have been individually tested against highly pathogenic avian influenza (HPAI) H5N1 viruses, the combination of both vaccines into a heterologous prime-boost strategy against HPAI H5N1 viruses has not been reported before.

METHODOLOGY/PRINCIPAL FINDINGS: We constructed DNA plasmid encoding H5HA (A/Shenzhen/406H/06, subclade 2.3.4) and generated VLP expressing the same H5HA and N1NA. We then compared neutralizing antibody responses and immune protection elicited with heterologous DNA-VLP, homologous DNA-DNA and VLP-VLP prime-boost strategies against HPAI H5N1 viruses in mice. We demonstrate that DNA-VLP elicits the highest neutralizing antibody titers among the three prime-boost strategies, whereas DNA-DNA elicits higher neutralizing antibody titers than VLP-VLP. We show that although all three prime-boost strategies protect mice from death caused by 10 MLD(50) of homologous and heterologous H5N1 challenge, only DNA-VLP and DNA-DNA protect mice from infection as manifested by no weight loss and no lung pathology. In addition, we show that although DNA-VLP and DNA-DNA protect mice from death caused by 1,000 MLD(50) of homologous H5N1 challenge, only DNA-VLP protects mice from infection. Moreover, we show that after 1,000 MLD(50) of heterologous H5N1 challenge, while all mice in PBS, VLP-VLP and DNA-DNA died, 3 of 6 mice in DNA-VLP actually survived. Finally, we show that DNA-VLP completely protects mice from infection after 1,000 MLD(50) of homologous H5N1 challenge even when the challenge was administrated at 60 days post the boost.

CONCLUSIONS/SIGNIFICANCE: These results provide strong support for clinical evaluation of heterologous DNA-VLP prime-boost strategy as a public health intervention against a possible H5N1 pandemic.