A newly published AIDS study could open another front in the battle against HIV infection by showing that gene therapy can be us

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问题      A newly published AIDS study could open another front in the battle against HIV infection by showing that gene therapy can be used to stop infected cells from spreading the deadly virus, researchers said.
     In a test-tube experiment believed to be the first of its kind, researchers based at Children’s Hospital of Philadelphia were able to block the operation of the" tat "gene that allows HIV to spread throughout the body from infected cells.
     Up to now, genetic AIDS research has concentrated on finding ways to help healthy cells withstand the ravages of the HIV virus that infects an estimated 16, 000 new victims a day, mainly in the developing world.
     But by working with human cells already infected with HIV, the team was able to reduce the tat gene’s virus-replicating functions by 80 percent to 90 percent, according to findings published in the journal Gene Therapy.
     That, researchers said, raises the possibility of a new gene therapy approach capable of supplementing the current drug-based treatment known as highly active anti-retroviral therapy, or HAART, which is used to stop HIV infection from becoming full-blown AIDS.
     In recent studies, HAART has proved to be a costly drug regimen that poses serious side effects for HIV patients while delivering questionable results.
     "This is proof of the concept that HIV replication could be inhibited by a genetic approach, though we’re not at 100 percent yet, "said Dr. Stuart Starr, a study coauthor and chief of immunologic infectious diseases at Children’s Hospital.
     "Everyone thinks of an antiviral approach, or an immunologic approach to HIV. This adds another option into the equation that could become more important as other options prove not to be totally successful."
     Key to the study was an artificially produced" antitat" gene provided by the Washington-based Research Institute for Genetic and Human Therapy.
     Children’s Hospital researchers used a mouse retrovirus to deliver the antitat gene into HIV-infected U-1 and ACH-2 cells, which were developed in the lab from the tissues of living HIV patients.
     They found that when the antitat protein combined with the tat gene, it successfully inhibited the gene’s operation without disturbing healthy cells or causing toxic side-effects.
     The study, funded by a private foundation, also found that the introduction of the antitat gene prolonged the survival of immune-system cells called CD4 + T lymphocytes.
     Start said researchers have entered preliminary discussions with a New England-based primate center ,where animal experiments could be carried out on infected macaque monkeys.
     If animal experiments proved successful, the Children’s Hospital team would hope to have a gene therapy treatment ready for human clinical trials in three to four years.
The researchers found that______.

选项 A、the gene therapy could be verified by animal experiments
B、the antitat gene may be artificially produced
C、antitat protein functions without causing any side-effects
D、antitat gene enhances the human immune system

答案D

解析 研究人员发现:A 基因疗法被动物实验所证明,文章中提到“researchers have...macaque monkeys.”但只是说,研究人员已经同New England-based primate center进行了初步的探讨,准备在受感染的短尾猿上作实验,并没有说已经被动物实验所证明,故A 错误。B 反tat基因可能被人工制造,文章中并没有提及。C 反tat基因的蛋白质能够在不引起任何副作用的基础上起作用,文章中只是说它不会引起有毒的副作用,而不是任何副作用。只有D 反tat基因可以赠强人体的免疫系统符合题意。
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