VOA标准英语2011--Scientists Target Antibodies That Work A

Scientists Target Antibodies That Work Against Many HIV Mutations

The search for a vaccine¹ against HIV/AIDS has been disappointing, in part because the virus cleverly changes to elude² the antibodies of the human immune system. Now, scientists have identified antibodies that may be effective against a broad range of HIV mutations.
Vaccines³ work by stimulating⁴ the body's own immune system to mount a defense⁵ against disease. But the human immune system just isn't very good at fighting off an HIV infection, in part because the virus is constantly mutating. That's been a big obstacle to developing an HIV vaccine, as Laura M. Walker of the Scripps Research Institute in California says.
"For HIV, current vaccines, because of the variability of the virus, don't induce antibodies that are able to recognize many different virus strains. And therefore, they usually are not very effective in preventing infection or preventing disease."
But Walker and her colleagues identified rare antibodies that were effective against a large number of the virus variations in circulation.
In the lab, they mixed those antibodies with HIV and saw that the virus was neutralized⁶, and a relatively⁷ small amount of antibodies did the trick.
"What's special about these antibodies is that they're able to inactivate⁸ the viruses at very low concentrations, which means that if you could induce these antibodies by a vaccine, you wouldn't need very much of them to provide some protection, which we think is very hopeful in terms of vaccine design," Walker says.
The researchers isolated⁹ specific molecules¹⁰ from the antibodies that attacked new targets in the virus. Walker says these molecules might be used as what she calls templates for potential vaccines.
"Then, hopefully you can develop vaccine candidates that can induce these types of antibodies in a large population of people."
Walker is cautiously optimistic that her work may lead to an effective HIV vaccine. However, she says her approach may help protect people who are newly exposed to HIV, but probably won't benefit those who already carry the virus.

1 vaccine   

n.牛痘苗，疫苗；adj.牛痘的，疫苗的

参考例句：

• The polio vaccine has saved millions of lives.脊髓灰质炎疫苗挽救了数以百万计的生命。
• She takes a vaccine against influenza every fall.她每年秋季接种流感疫苗。

2 elude   

v.躲避，困惑

参考例句：

• If you chase it,it will elude you.如果你追逐着它， 它会躲避你。
• I had dared and baffled his fury.I must elude his sorrow.我曾经面对过他的愤怒，并且把它挫败了；现在我必须躲避他的悲哀。

3 vaccines   

疫苗，痘苗( vaccine的名词复数 )

参考例句：

• His team are at the forefront of scientific research into vaccines. 他的小组处于疫苗科研的最前沿。
• The vaccines were kept cool in refrigerators. 疫苗放在冰箱中冷藏。

4 stimulating   

adj.有启发性的，能激发人思考的

参考例句：

• shower gel containing plant extracts that have a stimulating effect on the skin 含有对皮肤有益的植物精华的沐浴凝胶
• This is a drug for stimulating nerves. 这是一种兴奋剂。

5 defense   

n.防御，保卫；[pl.]防务工事；辩护，答辩

参考例句：

• The accused has the right to defense.被告人有权获得辩护。
• The war has impacted the area with military and defense workers.战争使那个地区挤满了军队和防御工程人员。

6 neutralized   

v.使失效( neutralize的过去式和过去分词 )；抵消；中和；使（一个国家）中立化

参考例句：

• Acidity in soil can be neutralized by spreading lime on it. 土壤的酸性可以通过在它上面撒石灰来中和。 来自《简明英汉词典》
• This strategy effectively neutralized what the Conservatives had hoped would be a vote-winner. 这一策略有效地冲淡了保守党希望在选举中获胜的心态。 来自《简明英汉词典》

7 relatively   

adv.比较...地，相对地

参考例句：

• The rabbit is a relatively recent introduction in Australia.兔子是相对较新引入澳大利亚的物种。
• The operation was relatively painless.手术相对来说不痛。

8 inactivate   

v.使…不活跃

参考例句：

• We put bacteria in an environment at low temperature to inactivate them.我们将细菌置於低温的环境中使之失去活性。
• Food processing destroys some nutrients,but can also inactivate toxins and increase the availability of other nutrients.食物加工破坏一些营养物质，但也可以灭活毒素，并增加其他营养物质的可用性。

9 isolated   

adj.与世隔绝的

参考例句：

• His bad behaviour was just an isolated incident. 他的不良行为只是个别事件。
• Patients with the disease should be isolated. 这种病的患者应予以隔离。

10 molecules   

分子( molecule的名词复数 )

参考例句：

• The structure of molecules can be seen under an electron microscope. 分子的结构可在电子显微镜下观察到。
• Inside the reactor the large molecules are cracked into smaller molecules. 在反应堆里，大分子裂变为小分子。