But in most people they studied, the virus in the blood did not match the sequence in the CD4 cells, indicating that HIV was hiding elsewhere.

但根据大部分人的研究表明，血液中的病毒序列并不和CD 4细胞内的相匹配，这就预示着HIV病毒可能另有藏身之处。

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For example, HIV enters cells of the immune system by binding to a receptor called CD4.

比如,HIV通过与CD4的受体结合,进入到免疫系统细胞中

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Two specific types of immune system cell that attack invaders - CD4 T-cells and natural killer cells - increased in number with age, with a higher rate of increase in women than in men.

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This consists of two sugar-protein molecules known as gp120 and gp41 that react with a protein called CD4, which is found on the surface of certain cells of the immune system.

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