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【medical-news】'Trojan Horse' vaccines for malaria, TB and
By Mike Nagle
The scientists, led by Prof Adrian Hill from the University of Oxford, have developed so called 'Trojan horse' vaccines that use virus DNA to get into a cell. However, the virus is genetically modified so that, once inside a cell, instead of reproducing and spreading, it produces both disease-killing antigens and other molecules designed to boost the immune system.
There are hundreds of millions of new cases of Malaria, TB and AIDS every year, resulting in nearly 8m deaths, according to the World Health Organisation (WHO).
These diseases are most prevalent in the developing world, yet many vaccines need to be kept frozen during transportation and storage. The WHO estimates that nearly half of all global vaccines are wasted, partly because they are stored improperly and therefore it is often very difficult for vaccines to be readily available to sufferers.
With his new vaccine in development, Prof Hill realised that, for it to be truly useful, he needed to make the vaccines easier to transport and store. He approached Cambridge Biostability to help solve the problem.
Howard Smith, technical and commercial manager at Cambridge Biostability told DrugResearcher.com: “The virus in the vaccine is extremely fragile; it normally has to be stored at –80°C.”
“We can take an otherwise labile vaccine and embed it in a solid glass formulation. We remove the water and the vaccine becomes thicker and then solid. It is then as stable as the glass itself, which is totally inert,” he said, describing the first step in the process.
“We can control the density of the glass and create a vaccine in powder form.”
The next step is to add a non-reactive, non-water liquid to turn the powder into a readily injectable form. The vaccines are then so stable, they can be preloaded into syringes or other injection devices. Indeed, Cambridge Biostability has data showing the vaccines are stable at 37°C for up to three years (and for 14 months at 55°C).
Smith added: “If something is going to degrade, it'll do it quite quickly and so if it has kept going that long, it's not going anywhere.”
The new technology isn't limited by what is in the vaccine and Cambridge Biostability are also working with Panacea Biotec, India's second largest vaccine producer, to develop vaccines against diphtheria, tetanus, whooping cough, hepatitis B and haemophilus influenza B (a major cause of bacterial meningitis and pneumonia in children).
Most vaccines cause the immune system to produce antibodies to fight off infection. However, many pathogens live inside cells where they avoid being attacked because the antibodies can't get to them.
Not only can this new type of virus-vectored vaccine get inside the cell, it also contains genes that produce molecules designed to stimulate, or adjuvant, the body's natural immune system to elicit a stronger, more prolonged response.
“The virus-vectored vaccine is priming the immune system to recognise a part of the virus so that if you later get the disease, the immune system kicks in and stops the virus from becoming established,” said Smith.
The research is part of a global collaboration that also includes scientists from the University of Sheffield, UK and the US-based Wistar Institute. The Bill & Melinda Gates Foundation has given $10m (?7.7m) towards the research and the group's first aim is to proceed to Phase I trials of the most promising malaria candidate vaccine. 'Trojan Horse' vaccines for malaria, TB and AIDS
疟疾、结核以及爱滋病'木马'疫苗
By Mike Nagle
作者
The scientists, led by Prof Adrian Hill from the University of Oxford, have developed so called 'Trojan horse' vaccines that use virus DNA to get into a cell. However, the virus is genetically modified so that, once inside a cell, instead of reproducing and spreading, it produces both disease-killing antigens and other molecules designed to boost the immune system.
There are hundreds of millions of new cases of Malaria, TB and AIDS every year, resulting in nearly 8m deaths, according to the World Health Organisation (WHO).
科学家们在牛津大学Adrian Hill教授带领下，已经研制出一种“木马”疫苗，即有DNA病毒转染细胞获得。该病毒一经进入细胞内就被修饰而不复制和传播，可以产生除病抗原和增强免疫系统反应的物质。
据世界卫生组织(WHO)报道，每年都有上千万计新发的疟疾、结核以及爱滋病患者，大约有8百万死亡。
These diseases are most prevalent in the developing world, yet many vaccines need to be kept frozen during transportation and storage. The WHO estimates that nearly half of all global vaccines are wasted, partly because they are stored improperly and therefore it is often very difficult for vaccines to be readily available to sufferers.
这些疾病在发展中国家非常普遍。由于很多疫苗在运输和储存时要保持冰冻状态。据WHO估计全球一半的疫苗被浪费掉了，很大原因在于储存方法不正确，致使很多疫苗不能使患者真正受益。
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作者:admin@医学,生命科学 2011-02-28 17:11
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