艾滋病疫苗研究
时间：2019-01-08 作者：英语课 分类：VOA2005（上）--环境科学探索
艾滋病疫苗研究
Two years ago, Jason Brenchley took part in an HIV vaccine trial sponsored by the U.S. National Institutes of Health. An NIH researcher himself, Mr. Brenchley says he volunteered to show others that the vaccine which contained no actual viruses, only bits of the organism's genetic 3 code was safe.
Mr. Brenchley: It is called a DNA 4 vaccine. They gave me DNA, which can code for proteins for HIV. Never in any circumstance is there a possibility to become infected with HIV from the vaccine.
Safe, yes but effective?
Anthony Fauci: There was no protection among those who received the vaccine versus 5 those that received a placebo 6.
Anthony Fauci directs infectious disease research at the National Institutes of Health, which is spearheading U.S. efforts to develop an HIV vaccine that works.
Dr. Fauci: Thus far there have been two [vaccine] candidates that have gone all the way through an efficacy trial, but unfortunately shown not to be effective in preventing HIV infection.
Dr. Fauci says the problems of combating HIV are myriad 7. For one thing, the virus has the ability to insert itself into the nucleus 8 of a human cell in effect "hiding" from an immune response. In addition the virus replicates 10 rapidly, often with mutations that make it difficult to target. But the obstacles do not end there.
Dr. Fauci: [With] Other viruses, such as smallpox 11 and measles 12, and polioneuromere the majority of people mount an immune response even if they never been vaccinated 13 that clears the natural infection. With HIV, there are virtually no incidents of a person who has completely cleared the virus from their body, which means that although some people can control the virus better than others, the body is having trouble making a protective immune response.
In other words, HIV vaccines 14 trigger an immune response. But that response has proven inadequate 15, just as the body's natural immune response to HIV infection does not eradicate 16 the virus. Dr. Fauci says the challenge is to create a vaccine that brings about an immune response far stronger than the virus would generate on its own.
Dr. Fauci: That is a formidable scientific obstacle and task.
Despite setbacks, vaccine trial volunteer Jason Brenchley says the initiatives are worthwhile.
Mr. Brenchley: You do experiments in science because you do not know what the answer is. And if the answer is not "yes it works," then you can learn something, you can learn how to improve on that product.
The inability to develop a vaccine with any measurable efficacy has some researchers looking in other directions. At Britain's National Institute for Medical Research, virology director Jonathan Stoye thinks it may be possible to combat HIV through gene 2 therapy.
Dr. Stoye: To take cells and try to convert them to being resistant 17 to infection by HIV. One would then put those cells back into the individual and hope that the cells would provide a barrier [to the virus].
Dr. Stoye says a gene has been discovered that helps both humans and Rhesus monkeys fight viruses. But the monkey gene has one molecule 18 that differs from its human counterpart. That difference, according to Dr. Stoye, appears to account for Rhesus monkeys' natural resistance to HIV. Altering the molecule in human cells might block further progression of the virus in those already infected, or could potentially provide a degree of immunity 19 for those who are HIV-negative.
Dr. Stoye acknowledges such a treatment would take years to develop and be prohibitively expensive for most people.
Dr. Stoye: If there were a vaccine that worked, I would not be suggesting this kind of approach. But we do not have a vaccine that works, and it is not clear when or if we will get such a vaccine.
Yet the quest for a vaccine continues, with several new formulations in various stages of testing. The relative low-cost of producing vaccines and the ease of administering them make them an ideal means of combating infectious disease with one important caveat 20, according to the NIH's Anthony Fauci.
Dr. Fauci: When a vaccine works, it is one of the greatest public health measures you can have. When it works.
Michael Bowman, VOA news, Washington.
注释：
vaccine [5vAksi:n] n. 疫苗
circumstance [5sE:kEmstEns] n. 环境
spearhead [5spiEhed] v. 充当先锋
infection [in5fekFEn] n. 感染
inadequate [in5Adikwit] adj. 不充分的
- 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。
- A single gene may have many effects.单一基因可能具有很多种效应。
- The targeting of gene therapy has been paid close attention.其中基因治疗的靶向性是值得密切关注的问题之一。
- It's very difficult to treat genetic diseases.遗传性疾病治疗起来很困难。
- Each daughter cell can receive a full complement of the genetic information.每个子细胞可以收到遗传信息的一个完全补偿物。
- DNA is stored in the nucleus of a cell.脱氧核糖核酸储存于细胞的细胞核里。
- Gene mutations are alterations in the DNA code.基因突变是指DNA密码的改变。
- The big match tonight is England versus Spain.今晚的大赛是英格兰对西班牙。
- The most exciting game was Harvard versus Yale.最富紧张刺激的球赛是哈佛队对耶鲁队。
- The placebo has been found to work with a lot of different cases.人们已发现安慰剂能在很多不同的病例中发挥作用。
- The placebo effect refers to all the observable behaviors caused by placebo.安慰剂效应是指由安慰剂所引起的可观察的行为。
- They offered no solution for all our myriad problems.对于我们数不清的问题他们束手无策。
- I had three weeks to make a myriad of arrangements.我花了三个星期做大量准备工作。
- These young people formed the nucleus of the club.这些年轻人成了俱乐部的核心。
- These councils would form the nucleus of a future regime.这些委员会将成为一个未来政权的核心。
- The DNA of chromatin must replicate before cell division.染色质DNA在细胞分裂之前必须复制。
- It is also easy to replicate,as the next subsection explains.就像下一个小节详细说明的那样，它还可以被轻易的复制。
- The bluetongue virus replicates in the insect. 蓝舌病病毒在这种昆虫体内繁殖。
- The chameleon's skin replicates the pattern of its surroundings. 变色龙的皮肤可随环境的模式而改变颜色。
- In 1742 he suffered a fatal attack of smallpox.1742年，他染上了致命的天花。
- Were you vaccinated against smallpox as a child?你小时候打过天花疫苗吗？
- The doctor is quite definite about Tom having measles.医生十分肯定汤姆得了麻疹。
- The doctor told her to watch out for symptoms of measles.医生叫她注意麻疹出现的症状。
- I was vaccinated against tetanus. 我接种了破伤风疫苗。
- Were you vaccinated against smallpox as a child? 你小时候打过天花疫苗吗？
- 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。
- The supply is inadequate to meet the demand.供不应求。
- She was inadequate to the demands that were made on her.她还无力满足对她提出的各项要求。
- These insects are very difficult to eradicate.这些昆虫很难根除。
- They are already battling to eradicate illnesses such as malaria and tetanus.他们已经在努力消灭疟疾、破伤风等疾病。
- Many pests are resistant to the insecticide.许多害虫对这种杀虫剂有抵抗力。
- They imposed their government by force on the resistant population.他们以武力把自己的统治强加在持反抗态度的人民头上。
- A molecule of water is made up of two atoms of hygrogen and one atom of oxygen.一个水分子是由P妈̬f婘̬ 妈̬成的。
- This gives us the structural formula of the molecule.这种方式给出了分子的结构式。
- The law gives public schools immunity from taxation.法律免除公立学校的纳税义务。
- He claims diplomatic immunity to avoid being arrested.他要求外交豁免以便避免被捕。