BBC News—2007，06，23

　　科学家表示，一个存在已久的关于HIV是怎样慢慢衰竭身体的免疫系统的理论是错误的。 

　　HIV侵袭人体免疫细胞，即辅助性T细胞，通常需要几年的时间将T细胞渐渐耗尽。被感染的细胞曾被认为会制造更多的HIV粒子并导致机体内更多的T细胞活化，从而T细胞被感染杀死。 

　　由联合国和美国研究人员的模拟实验显示：若上述都是正确的，细胞在数月内就会全部死亡，而无需几年的时间。 

　　由亚特兰大埃默里大学和伦敦的儿童健康协会指导的研究在《公共科学图书馆.医学》杂志上已有报道。 

　　研究人员用一个数学模型来表示T细胞被制造和死亡的过程。利用这个模型，他们证明目前的理论：T细胞的不受控制的循环，感染，HIV复制和细胞死亡的“逃亡”假说是有瑕疵的。他们下结论：无法解释在HIV感染过程中T细胞耗尽的速度如此缓慢。如果理论是正确的，T细胞数目在数月内将会下降到一个非常低的水平，而无需几年。 

　　缺乏必然性 

　　来自伦敦大帝国学院的Jaroslav Stark教授说：“科学家在T细胞被HIV消耗的全过程方面从没有一个完整的理解，因此他们不能彻底解释为什么HIV破坏T细胞的速率是如此的慢。”

　　“我们新的跨学科研究对流行的理论，即HIV是怎样影响T细胞的，提出严重的质疑。这意味着为理解HIV减慢细胞破坏的过程背后的独特结构，还需要更进一步的研究。”

　　研究者认为一个可能的解释是：可能病毒会慢慢的适应其感染的过程。但他们强调还需进一步的分析以证实这个替代的理论。 

　　Stark教授说：“如果HIV消耗这种白细胞的过程是可以被确认，那么它可能会为潜在的新治疗方法奠定基础。” 

　　Roger Pebody为席金斯基金会的治疗顾问，表示：“HIV是一个极为复杂的病毒，研究需继续努力并精确的确定它的机制。”“在能够清楚的下结论之前，我们需要在这个领域做更多的研究。” 

韩冠斌    一校    

杨悦      二校

HIV infection theory challenged

BBC News - June 23, 2007

A longstanding theory of how HIV slowly depletes the body's capacity to fight infection is wrong, scientists say. 

HIV attacks human immune cells, called T helper cells. Loss of these cells is gradual,often taking many years. 

It was thought infected cells produced more HIV particles and that this caused the body to activate more T cells which in turn were infected and killed. 

Modelling by UK and US researchers suggeststhat, if that was true, cells would die out in months not years. 

The study, led by Emory University in Atlanta and the Institute of Child Health in London, was published in the journal PLoS Medicine. 

The researchers used a mathematical model of the processes by which T cells are produced andeliminated. 

Using this they showed that the current theory of an uncontrolled cycle of T cell activation, infection, HIV production and cell destruction - dubbed the "runaway" hypothesis - was flawed.

They concluded that it could not explain the very slow pace of depletion that occurs in HIV infection. 

If the theory were correct, then T helper cell numbers would fall to very low levels over a number of months, not years. 

Lack of certainty 

Researcher Professor Jaroslav Stark, from Imperial College London, said: "Scientists have never had a full understanding of the processes by which T helper cells are depleted in HIV, and therefore they've been unable to fully explain why HIV destroys the body's supply of these cells at such a slow rate. 

"Our new interdisciplinary research has thrown serious doubt on one popular theory of how HIV affects these cells, and means that further studies are required to understand the mechanism behind HIV's distinctive slow process of cellular destruction." 

The researchers think one possible explanation could be that the virus slowly adapts itself over the course of the infection. 

But they stress that further analysis is needed to verify this alternative theory. 

Professor Stark said: "If the specific process by which HIV depletes this kind of white blood cell can be identified, it could pave the way for potential new approaches to treatment." 

Roger Pebody, a treatment advisor at HIV charity Terrence Higgins Trust, said: "HIV is an incredibly complex virus and research is ongoing to try and establish exactly how it works. 

"We need more studies in this area before we can draw any clear conclusions."