科学家认为罹患阿兹海默症的原因，是由于患者脑中沈积着淀粉样蛋白，日本国立长寿医学中心研究所的专家，目前正在研发可以去除这种淀粉样蛋白的疫苗，疫苗在施用于实验小鼠身上后，发现具有恢复智慧的功效。
这种新研发的疫苗，是在不具病原性的病毒壳内注入可制造淀粉样蛋白质的基因，以口服方式摄取的话，可出现「伪病毒」的反应，淋巴球能制造出攻击淀粉样蛋白质的抗体，此抗体附着在沈积在脑中的淀粉样蛋白上面，并将此蛋白剥除。
研究小组利用基因技术，让28只实验小鼠罹患阿兹海默症，在发病的情况下，让其中的14只服用疫苗，其余不服用。
结果，服用疫苗的小鼠在三个月后，几乎都能通过记忆力、学习能力等四种智力测验，恢复到等同于阿兹海默病发病前的程度。另一方面，未服用疫苗的小鼠之认知能力丧失了一大半。这次研发的疫苗并非利用直接注射蛋白质等的方式，所以安全性高、可量产，只要饮用药液即可，比较简单。
科学家表示，如果整个疫苗的研发作业完成后，就可以解决目前欧美正在研发的疫苗所遭遇的难题，也就是安全性及成本等问题。日本的研究人员希望可以很快地进行下个阶段的研究，针对少数的阿兹海默患者进行临床实验。
(资料来源 : Reuters)
英文原文：
Alzheimer's vaccine works on mice: Japan scientist
Thu Mar 29, 2007 2:04PM EDT
By Isabel Reynolds
TOKYO (Reuters) - Japanese scientists have developed an oral vaccine for Alzheimer's disease that has proven effective and safe in mice, the director of a research institute behind the project said on Thursday.
The team is preparing to move to small-scale clinical trials in humans, possibly this year, said Takeshi Tabira, director of the National Institute for Longevity Sciences in Aichi, central Japan.
"We hope the Phase I trials go well," Tabira said. "Animals are able to recover their functions after developing symptoms, but humans are less able to do so. It may be that this only works in the early stages of the disease, when symptoms are light."
When administered to mice suffering from the disease, which causes dementia and is currently incurable, the vaccine reduced the amount of amyloid plaques in the brain and improved mental function.
Amyloid plaques are believed to be at the root of Alzheimer's -- a growing problem for aging populations around the world. The disease affects five million in the United States alone, the Alzheimer's Association said in a report last week.
The treatment did not cause inflammation or bleeding in the brains of the mice, Tabira said.
The vaccine is made by inserting amyloid-producing genes into a non-harmful virus. When taken orally, the virus stimulates the immune system to attack and break down the amyloid proteins in the brain, Tabira said.
The treatment was tested on 28 mice genetically modified to develop Alzheimer's disease. Half the animals were given a dose of the vaccine at the age of 10 months, while the control group were not treated.
Three months later, tests showed mental function in the treated mice had returned to levels close to those before they developed Alzheimer's symptoms.
U.S. drugmaker Wyeth and its Irish partner Elan Corp have an Alzheimer's vaccine called ACC-001 in early stage human trials.
The Japanese research, carried out in conjunction with scientists at Nagoya University and others, is to be published by the Federation of American Societies for Experimental Biology in July.
