An experimental vaccine developed by a Johnson & Johnson (JNJ) unit and the U.S. military protected monkeys against an animal version of the AIDS virus, a study found.
Monkeys that got the vaccine were as much as 83 percent less likely than those that got a dummy shot to become infected with simian immunodeficiency virus, or SIV, researchers from Harvard Medical School and the U.S. Military HIV Research Program said in a study published online in the journal Nature today. They now plan to test the vaccine in humans.
While previous vaccine trials have helped to keep AIDS at bay by controlling the virus in infected monkeys, this is the first to prevent monkeys from becoming infected, said Dan Barouch, a professor of medicine at Harvard’s Beth Israel Deaconess Medical Center who led the study.
“There’s more hope now than ever before that the development of a safe and effective HIV vaccine is indeed possible,” Barouch said in a telephone interview today.
The research builds on the first partially successful HIV vaccine trial in Thailand in 2009, which showed that two inoculations that hadn’t worked on their own offered some patients protection when given in combination. The first prompts the immune system to produce so-called killer T-cells that are primed to hunt and destroy infected cells, and antibodies that go after the virus itself. The second repeats the dose, boosting the body’s defenses.
The results in that trial showed about a 31 percent reduction in infections compared with placebo, though the benefit waned after a year.
The search for a vaccine to prevent HIV has eluded scientists since the early 1980s. While there are treatments for HIV that limit the virus in the body, holding AIDS at bay for years, there is no cure. AIDS, which is caused by HIV, killed 1.8 million people in 2010, and new infections with the virus fell to 2.7 million, according to a November report by the Joint United Nations Programme on HIV/AIDS.
Barouch and colleagues experimented with four different combinations of the so-called prime-boost approach, using disabled cold viruses and pox viruses as Trojan horses to ferry SIV proteins into the monkeys. Unlike other vaccine trials, they then exposed the animals to a strain of the virus that was genetically different to the one used to design the vaccine.
“That’s called stacking the cards against yourself,” said Anthony Fauci, director of the U.S. National Institute of Allergy and Infectious Diseases, part of the National Institutes of Health, which helped to fund the research.
After the first of six exposures, as few as 12 percent of the vaccinated monkeys became infected, compared with 75 percent of those that got a placebo. While most of the animals were infected by the sixth exposure, that doesn’t mean the same would be seen in humans because the virus used in the trial was about 100 times more infectious than that to which humans are typically exposed, Barouch said.
The scientists also found that the vaccines worked best when they contained a viral protein called Env, which is used to build the outer shell of the virus. That indicates
The most promising of the combinations was one that featured a prime vaccine developed by Crucell NV, the Leiden, Netherlands-based company that Johnson & Johnson, of New Brunswick, New Jersey, bought last year, and a booster developed by the U.S military and NIAID. The researchers plan to test that combination in people “in the near future” Barouch said.
The research was funded by the National Institutes of Health, the U.S. military, the Bill and Melinda Gates Foundation and the Ragon Institute at Harvard, the Massachusetts Institute of Technology and Massachusetts General Hospital. (Bloomberg)
<한글 기사>
"원숭이에이즈바이러스 백신 실험 성공"
미국에서 에이즈 바이러스(HIV)의 동물 버전인 원숭이에이즈바이러스(SIV) 감염을 예방하는 백신 실험이 성공함에 따라 HIV 백신 개발에 대한 기대가 높아지고 있다.
하버드대 의대 연구진과 미 국방부 HIV 연구프로그램은 4일(현지시간) 과학 학술지 네이처 온라인판에 실은 논문을 통해 SIV 예방 백신 테스트 결과를 발표하면서 백신을 맞은 원숭이들이 가짜 백신을 접종한 원숭이에 비해 SIV 감염 비율이 83% 낮 았다고 밝혔다.
연구팀은 예방 백신을 접종한 원숭이들을 SIV 바이러스에 6차례 노출시킨 후 감 염 여부를 확인한 결과 실험 대상 중 12%만이 감염된 것으로 나타났다고 전했다. 반 면 가짜 백신을 접종한 원숭이의 경우 같은 조건에서 75%의 감염률을 보였다.
과거 실험은 SIV에 감염된 원숭이의 바이러스를 통제하는 것을 목표로 했지만 이번 실험은 감염 자체를 막은 것이라고 연구를 주도한 댄 바로치 하버드대 `베스 이스라엘 디코네스' 의료센터 교수가 말했다.
바로치 교수는 "안전하고 효과적인 HIV 백신 개발이 실제로 가능하다는 희망이 이전 어느 때 보다 커졌다"고 자평했다.
연구팀은 또 이번에 실험을 거친 백신에 Env로 불리는 바이러스성 단백질이 더해졌을 때 가장 큰 효과를 발휘한다는 것을 발견했다.
연구진은 내년 1월부터 인간을 대상으로 이 백신의 효능을 테스트할 예정이다.
학계는 이번 연구가 HIV에 대한 면역 시스템의 핵심을 식별해내는데 도움을 줄 것이라며 환영하고 있다.
이번 연구는 2009년 태국에서 진행된 HIV 백신 실험의 성과를 토대로 이뤄졌다.
당시 태국인 1만6천여명을 상대로 3년여에 걸쳐 임상시험을 진행한 미 육군의 제롬 킴 대령 등은 혼합 백신을 활용, HIV 감염 위험을 31% 이상 감소킬 수 있다고 발표했다.
