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【drug-news】疟疾疫苗？
The most severe form of malaria hits pregnant women and children the hardest. A joint study between Karolinska Institutet in Sweden and Makerere University in Uganda has now produced some important findings on how the malaria parasite conceals itself in the placenta.
Plasmodium falciparium is the name of by far the most virulent of the four malaria parasites that infect man. It is particularly dangerous in that it also infects the placenta of pregnant women, with fatal consequences for both her and the foetus. This, combined with the often feeble medical resources of malaria-stricken countries, can lead to such serous complications that the mother dies during delivery.
"For some reason, women in their first pregnancy lose the semi-immunity that is normally found in adults," explains Niloofar Rasti, a KI graduate student who has been working with the study. "The placenta seems to be an anatomically favourable environment for a subpopulation of the parasites."
The research group from Karolinska Institutet, under the leadership of Professor Mats Wahlgren, has been working with colleagues from KI's partner university in Uganda to study in detail how the parasite infects the placenta. Their results, which are published in the American scientific journal PNAS, can enable the development of vaccines and therapies to combat severe malarial infections.
During one particular phase of its lifecycle, the parasite enters human red blood cells, where it produces proteins that attach themselves to receptors in the wall of the blood vessels. This causes the red blood cells to accumulate in organ capillaries, and gives rise to life-threatening symptoms. Adults who have been infected several times can become partly immune as their defence system gradually starts to recognise the parasite's proteins. When the placenta is formed, however, a new environment is introduced with a different set of receptors. This means that a new growth niche is made available to a subpopulation of the parasites.
Earlier studies have suggested that each protein from the parasite attaches to only one specific protein, a receptor, in the placenta. Ms Rasti and her colleagues suspected, however, that the natural mechanisms are more complex than laboratory studies have shown. They therefore collected and analysed placentas on site in Uganda.
"Most of the parasites we studied could bind to three different receptors in the placenta," she says. "This would mean that a future vaccine cannot be based on the principle of one protein-one receptor, as was previously believed."
Now that scientists know that several placental receptors are involved in the binding mechanism, attention will be shifted to the parasite itself, and whether it produces many different surface proteins or if one and the same protein is able to bind to many host receptors. 认领了 认领，试一试
New findings could lead to vaccine for severe malaria
有助于研制恶性疟疾疫苗的新发现
The most severe form of malaria hits pregnant women and children the hardest. A joint study between Karolinska Institutet in Sweden and Makerere University in Uganda has now produced some important findings on how the malaria parasite conceals itself in the placenta.
最严重的疟疾对怀孕妇女和小孩的影响最大。瑞典Karolinska医学院和乌干达Makerere大学开展了一项联合研究，对疟疾寄生虫如何隐藏在胎盘中的已有了相当程度的重要发现。
Plasmodium falciparium is the name of by far the most virulent of the four malaria parasites that infect man. It is particularly dangerous in that it also infects the placenta of pregnant women, with fatal consequences for both her and the foetus. This, combined with the often feeble medical resources of malaria-stricken countries, can lead to such serous complications that the mother dies during delivery.
Plasmodium falciparium是目前为止感染人类的疟原虫中4种致病力最强的疟疾寄生虫的总称。疟原虫能够感染孕期妇女的胎盘，这是非常危险的，可对孕妇和胎儿都有可能产生致命的危害。同时，疟疾肆虐的国家医疗条件简陋，在分娩过程有可能导致孕妇血液并发症而致死。
"For some reason, women in their first pregnancy lose the semi-immunity that is normally found in adults," explains Niloofar Rasti, a KI graduate student who has been working with the study. "The placenta seems to be an anatomically favourable environment for a subpopulation of the parasites."
“由于某些原因，妇女在初次怀孕中失去了成人通常具有的半免疫力。”参与这项研究的Karolinska医学院研究生Niloofar Rasti解释说，“对感染疟疾寄生虫的人来说，在解剖学上看来胎盘似乎提供了寄生虫生长的有利环境。”
The research group from Karolinska Institutet, under the leadership of Professor Mats Wahlgren, has been working with colleagues from KI's partner university in Uganda to study in detail how the parasite infects the placenta. Their results, which are published in the American scientific journal PNAS, can enable the development of vaccines and therapies to combat severe malarial infections.
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作者:admin@医学,生命科学 2011-01-15 05:14
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