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Vaccine Aims at Fly Host of Disease Parasite
新型疫苗直接對付寄生蟲的宿主
Leishmaniasis is a sometimes fatal disease marked by skin ulcers, fever, and spleen and liver problems. It currently affects about 12 million people, mostly in the developing world, with about 2 million new infections annually. It’s caused by a parasite, which is spread by sand flies.
利什曼病有時候是致命的——其主要特征為皮膚潰瘍、發(fā)燒以及脾臟和肝臟問題。目前大約有1200萬人深受其害，大多患者集中在發(fā)展中國家。而且每年約有200萬新的感染者。它由一種寄生蟲引發(fā)，而這種寄生蟲是由沙蠅傳播的。
There is not yet a good vaccine against leishmaniasis. But researchers have shown that it may be worthwhile to target not the parasite—but its fly host. The report good results in non-human primates in the journal Science Translational Medicine.
目前還沒有哪種疫苗能夠很好的對抗利什曼病。但是研究人員表示，可以考慮不直接對付該寄身蟲，而是去對付它的宿主——沙蠅。該研究在非人類靈長動物身上取得了良好效果。這項研究結(jié)果發(fā)表在《科學(xué)轉(zhuǎn)化醫(yī)學(xué)》雜志上。
Vaccines usually trigger our immune systems to rally against a pathogenic agent. If that agent should actually show up, the immune system can disarm it.
疫苗通常會觸發(fā)我們的免疫系統(tǒng)去對抗病原體。如果病原體出現(xiàn)了，免疫系統(tǒng)就可以將其鏟除。
But in this case, scientists aimed at the carrier—the sand fly. When an infected fly bites a victim, it injects parasites and its own saliva. So the researchers subjected monkeys to repeated bites from uninfected sand flies, then to bites from infected sandflies. And the monkeys bitten first by uninfected flies were partially protected when confronted with the leishmaniasis parasite. Seems that exposure to fly saliva alone could elicit an immune response.
但是針對這種疾病，科學(xué)家將目標(biāo)鎖定為該寄生蟲的載體——沙蠅。當(dāng)一個受到感染的沙蠅咬傷受害者時，它就會在受害者體內(nèi)注入寄生蟲以及它自己的唾液。因此，研究人員先讓猴子多次被未受感染的沙蠅叮咬，然后再被受到感染的沙蠅叮咬。起初被未受感染的沙蠅叮咬過的猴子，在面對利什曼病寄生蟲的時候獲得了部分保護(hù)。由此可見，被未受寄生蟲感染的沙蠅叮咬是可以引起免疫反應(yīng)的。
The researchers then determined that one particular protein in the sand fly’s saliva kicked the immune system into action. A vaccine based on that protein offered partial protection, with 7 of 10 monkeys that got it developing smaller ulcers and a stronger immune response than their unvaccinated peers when infected with the parasite.
最終研究人員斷定：沙蠅唾液中一種特定的蛋白質(zhì)刺激免疫系統(tǒng)起了作用。一種以這一蛋白質(zhì)為基礎(chǔ)的疫苗似乎可以提供部分保護(hù)——在實驗中，10個接種了這種疫苗的猴子里面有7個長出了較小的潰瘍，并且與未接種疫苗的猴子相比，當(dāng)感染了這種寄生蟲時它們擁有更強(qiáng)的免疫反應(yīng)。
This protein can be generated and purified easily from E. coli, which means that it’s possible to get large quantities of it to produce a potential future human vaccine against leishmaniasis. Which would make this saliva-based protection nothing to spit at.
大腸桿菌可以很容易地生成并凈化這種蛋白質(zhì)。這就意味著我們能夠獲得大量這種蛋白質(zhì)，用以生產(chǎn)可對抗利什曼病的疫苗——一種有潛力在未來適用于人類的疫苗。而這將使這種以唾液為基礎(chǔ)的蛋白質(zhì)不再被蔑視。