모기 이용 말라리아 백신 개발 실험



출처 : 연합뉴스 2010/08/30 17:06 
http://www.yonhapnews.co.kr/international/2010/08/30/0606000000AKR20100830189000009.HTML?template=3397

(베를린 dpa=연합뉴스) 독일 과학자들이 말라리아 병원충을 옮기는 모기에 물리게 해 말라리아 면역력을 갖게 하는 방법을 연구하고 있다고 밝혔다.

   베를린 소재 막스 플랑크 감염생물학 연구소의 카이 마튜세프스키박사 연구팀은 항생제를 투여하면서 말라리아 병원충에 물리게 해 면역력을 지니게 하는 동물 실험을 실시했다.

   이들은 말라리아 병원충을 가진 모기가 운반하는 종충을 실험용 쥐에게 감염시켰다.

   이 종충들은 쥐의 간으로 이동해 대량 증식하면서 혈액 속 적혈구를 파괴해 말라리아를 일으키는 낭충으로 성장했다.

   하지만 이 쥐에 말라리아 발병을 억제하는 항생제를 동시에 투입한 결과 낭충의 적혈구 침입이 억제돼 적혈구가 보존되고 말라리아가 발병하지 않는 사실이 확인됐다.

   이 쥐들은 이후 계속된 실험에서 항생제를 투입하지 않아도 말라리아에 걸리지 않을 만큼의 면역력을 얻게 되는 것으로 나타났다.

   이번 실험에 쓰인 항생제는 클린다마이신과 아지스로마이신으로 모두 싼값에 구할 수 있는 복제의약품이다.

   연구팀은 이들 항생제를 이용해 내년 여름 이전에 아프리카 사하라사막 이남 지역에서 임상실험 실시를 추진하고 있다.

   이번 연구 결과는 전문지 사이언스 병진 의학(Science Translational Medicine)에 발표됐다.

   maroonje@yna.co.kr

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German scientists discover ‘needle-free’ malaria vaccine

Medicine | 09.08.2010
http://www.dw-world.de/dw/article/0,,5879942,00.html


By combining antibiotics and malaria-infected mosquitos, researchers find that mice are protected. Human clinical trials will be just around the corner.

Deep in a lab, in carefully sealed incubators, mosquitos, which normally are malaria carriers, may this time actually be part of the solution.

Kai Matuschewski and his research team from the Max Planck Institute for Infection Biology in Berlin used mosquitoes to infect test mice with malaria. At the same time, they gave the mice antibiotics for three days and the mice showed no signs of the disease.

Matuschewski says this means that he and his research team may have discovered the first so-called “needle-free” malaria vaccine. Their research was published last month in the journal Science Translational Medicine.

If successful, the vaccine would use a combination of drugs and the mosquito itself to prevent the onset of malaria. It could be a boon to billions of people worldwide who are at risk for the disease, which mainly affects people living in temperate climates.

Matuschewski said the idea behind their research was to “combine a classical prophylaxis aspect – which is antibiotic treatment – (that travelers use to protect themselves against malaria), together with a natural exposure.”

“The mosquito is our sort of syringe that delivers the pathogen and we stop the parasite from growing in the liver through antibiotic prophylaxis,” he said.

‘The mice don’t get sick’

While feeding, a malaria-carrying mosquito injects something called a sporozoite, which is the cell form that infects the new host.

In this case, that would be the mouse. In the real world, it could be a human. The sporozoites migrate to the liver, where they replicate massively and mature to the disease-causing blood stage cells called merozoites.

In this new German study, the merozoites continued to develop in the liver cells, but the antibiotics prevented them from infecting the red blood cells, which meant that the mice didn’t get malaria symptoms.

With this treatment the mice not only didn’t get sick, but they also developed long-term immunity.

The mice were infected with sporozoites again after 40 days, four months, and six months, this time without adding antibiotics, and all the animals had complete protection against malaria.

Antibiotic resistance

The antibiotics the scientists used were clindamycin and azithromycin, that are both generic, cheap and readily available. This is good news for poorer countries, but Dr. Michael Knappik, from the Berlin Center for Tropical and Travel Medicine, pointed out that there are drawbacks with using antibiotics in the long term.

“We have growing resistance against the malaria drugs we use at the moment,” he said, “and that’s a big problem especially in Southeast Asia, and this of course can also arise in these new antibiotic treatments.”

Matuschewski and his team hope to reduce the likelihood of antibiotic resistance by administering the drugs once a year – at the onset of the rainy season. He added that antibiotic resistance isn’t as pronounced in Africa as it is in Western countries, so the benefits could outweigh the concerns.

Clinical trials to begin next year

If successful, this new treatment could dramatically lower the one million deaths worldwide from malaria every year.

Around 600 Germans contract the disease each year, and Sebastian Hofmann was one of the unlucky ones. Seven years ago at age 19, Hofmann went backpacking across West Africa, and, despite the usual malaria prevention measures – including medicine, insect repellent and mosquito nets – he still contracted the disease.

“I was hallucinating. I was sweaty,” he remembered, “I thought I was somehow in the state of being really drunk and having a really bad flu.”

Hofmann contracted the worst strain of malaria and fell into a coma for three days, although he eventually recovered. While this new treatment isn’t targeted at travelers in general – because you need to be infected with malaria first for it to work – it could make a big difference for people living in severely affected regions.

“In endemic areas in Kenya, in East Africa, people live there for 20 years, get infected probably sometimes 100 times a year and they always develop parasites,” Matuschewski said. “So to achieve something like anti-parasitic sterile immunity is almost impossible. So what we want is to protect against disease.”

Put another way, even if children living in malaria regions are protected daily with bed nets, according to Matuschewski all this does is delay their potential exposure to the disease and subsequent symptoms and complications.

So rather than trying to prevent all mosquito bites – which is virtually impossible – this new treatment uses the infection as a part of the solution in combination with the antibiotic.

Because the antibiotics are readily available, Matuschewski and his research team hope that clinical trials could start in sub-Saharan Africa, as early as the beginning of summer next year.

While they’re excited about their findings, scientists like Dr Johannes Friesen from the Max Planck Institute for Infection Biology in Berlin, were careful to point out that their research is just “one component to fight the disease.”

Author: Cinnamon Nippard


Editor: Cyrus Farivar

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참고 : 말라리아를 예방하는 항생제
http://radar.ndsl.kr/tre_View.do?cn=GTB2010070554

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말라리아는 이탈리아어로 나쁜(또는 미친)의 뜻을 가진 ‘Mal’과 공기를 뜻하는 ‘aria’가 결합한 용어로, 19세기 말엽까지도 말라리아가 나쁜 공기를 통해 전파된다고 믿어서 그런 이름이 붙었다.

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감염된 모기(학질모기)가 사람을 물면 모기의 침샘에 있던 말라리아 원충이 혈액 내로 들어간다. 이렇게 들어간 원충은 사람의 간으로 들어가서 성장하며 잠복기가 끝나면 사람의 적혈구로 침입하여 발열하게 된다. 원충이 적혈구에서 다시 성장하면서 암수 생식모체라는 것이 만들어지는데 이 때 말라리아 매개모기인 중국 얼룩날개모기가 사람의 피를 흡혈하면 이들이 다시 모기를 감염시킴으로서 점차 전파된다.