为了在病毒中分离这种“非变异”成分，内伯尔和他的同事们使用一个两步接种过程。

To get at these non-mutating parts of the virus, Nabel and his colleagues used a two-step vaccination process, called "prime-boost."

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IOF是一个于1987年在瑞士伯尔尼注册的国际性组织，它在世界范围内的83个国家、地区拥有167个国家学会团体。

IOF is an international organization registered in Berne, Switzerland in 1987. It has a committee of 167 national Societies in 83 countries, territories and regions.

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